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Lagoon sludge is a by-product of pig production in North Carolina. Sludge contains nutrients, minerals, and cellular biomass. Sustainable management of sludge is crucial to avoid accumulation impacts on lagoon performance. This study investigated sonication as a potential pre-treatment for sludge. The impact of sonication on sludge bio-methane potential and degradation kinetics was evaluated. At sonication energy dosage of 20,400 kJ.kg TS −1, the dissolved total carbon (DOC) and soluble chemical oxygen demand (SCOD) increased from 446 to 1055 mg L−1 and from 2297 to 9239 mg O2 L−1, respectively. In the bio-methane potential (BMP) study, cumulative biogas and bio-methane yield increased from 21.0 to 28.4 mL biogas.g VS −1 and from 15.0 to 21.3 mL CH4.g VS −1 due to sonication. Sonicated sludge reached 95% of its experimental biomethane yield more than 10 days earlier compared to raw sludge. The first order kinetics equation showed the highest co-efficient of determination (R 2 ) and least root mean square error (RMSE) when fitted to raw sludge bio-methane production, while transference model was the best fit for sonicated sludge bio-methane production. The transference model substantially overestimated the maximum gas production rate for sonicated sludge. A significantly higher hydrolysis constant (p -value < 0.05) was observed for sonicated sludge (0.6 day−1) in comparison to raw sludge (0.08 day−1). Findings suggest sonication is a promising tool to aid organic matter and nutrient fractionation, and energy recovery pathway but the high energy inputs are still a barrier. • Sludge sonication increased organic matter and nutrients in dissolved fraction. • Sonicated sludge degradation yielded higher bio-methane in shorter retention time. • First-order kinetics and transference model best explained sludge's degradation. • High energy input may challenge wider adoption of sonication treatment. [ABSTRACT FROM AUTHOR]

Subtidal circulation patterns were studied along an elongated hypersaline system. Month-long data were collected using three acoustic Doppler current profilers. These profilers were moored at depths of around 15 m in three locations: 10 km inland from the mouth of the lagoon, within the central region, and near the head of the lagoon. The variability of temporal and spatial subtidal circulation was explored using Empirical Orthogonal Functions analysis, which explained 93% of the variability through the first three modes. The first mode was influenced by tidal advection, resulting in a tidally-driven residual circulation for elongated channels, with inflows occurring over the shoals and outflows in the deeper channel sections. During the neap-tide cycle, inverse density gradients became relevant, coinciding with the peaks of mode 2 amplitude that accounted for 15% of the total variability. The gravitational circulation exhibited its highest intensity near the head, characterized by a vertically sheared flow with inflow occurring near the surface and outflow underneath. Predominant onshore wind stresses had a significant impact on the subtidal circulation and displayed a strong correlation with the mode 3 amplitude, explaining 11% of the total variability. Wind-driven circulation exhibited a vertically sheared profile, characterized by downwind near-surface flow and upwind flow underneath in the lagoon mouth and head, and a homogeneous downwind profile in the central part of the lagoon. It is concluded that tidal stresses governed the subtidal circulation, followed by density gradients, and wind stresses modified spatial circulation patterns induced by tides and density gradients. This research provides new observational evidence on tidal residuals in long channels and contributes to the understanding of the interactions between the main subtidal circulation drivers in hypersaline lagoons. • Tidal advection governed the subtidal circulation of a hypersaline coastal lagoon. • Density gradients became relevant during neap tide and dominated the circulation near the head. • Wind-driven flow appeared during strong wind conditions and displayed a vertically sheared profile near the mouth. [ABSTRACT FROM AUTHOR]

This study investigates for the first time the contamination of water and sediment of the Venice Lagoon by twenty Contaminants of Emerging Concern (CECs): three hormones, six pharmaceutical compounds (diclofenac and five antibiotics, three of which are macrolides), nine pesticides (methiocarb, oxadiazon, metaflumizone, triallate, and five neonicotinoids), one antioxidant (BHT), and one UV filter (EHMC). Water and sediment samples were collected in seven sites in four seasons, with the aim of investigating the occurrence, distribution, and possible emission sources of the selected CECs in the studied transitional environment. The most frequently detected contaminants in water were neonicotinoid insecticides (with a frequency of quantification of single contaminants ranging from 73% to 92%), and EHMC (detected in the 77% of samples), followed by BHT (42%), diclofenac (39%), and clarithromycin (35%). In sediment the highest quantification frequencies were those of BHT (54%), estrogens (ranging from 35% to 65%), and azithromycin (46%). Although this baseline study does not highlight seasonal or spatial trends, results suggested that two of the major emission sources of CECs in the Venice Lagoon could be tributary rivers from its drainage basin and treated wastewater, due to the limited removal rates of some CECs in WWTPs. These preliminary results call for further investigations to better map priority emission sources and improve the understanding of CECs environmental behavior, with the final aim of drawing up a site-specific Watch List of CECs for the Venice Lagoon and support the design of more comprehensive monitoring plans in the future. [Display omitted] • The first investigation of twenty CECs in water and sediment of the Venice Lagoon. • The most frequently quantified contaminants in water were neonicotinoids and EHMC. • Estrogens and BHT had the higher quantification frequencies in sediment samples. • The major emission sources turned out to be tributary rivers and treated wastewater. • The study provides baseline knowledge to draft a Watch List for the Venice Lagoon. [ABSTRACT FROM AUTHOR]

This study has carried out a systematic review of 36 scientific papers (reporting 63 case studies) published in the last 15 years about the treatment of industrial, agri-food and municipal wastewater in lagoons. A concentration of studies from a few countries (Italy, Algeria and Iran) and about municipal wastewater (70% of papers) was revealed by the bibliographic analysis. Aeration was supplied in more than 50% of case studies; the storage capacity of lagoons (adopted as a measure of size) was extremely variable (over seven orders of magnitude), while their depth was generally lower than a few metres. The efficiency of lagoon treatments at removing COD was in a wide range (25–98%). Very few studies analysed the energy intensity of treatments in lagoons. The meta-analysis applied to a further selection of 10 papers with 29 case studies revealed significant differences in pH and dissolved oxygen concentration, due to aeration or type of treated wastewater. Treatment efficiency was higher in aerated lagoons compared to non-aerated systems, and did not depend on the type of treated wastewater. Based on the analysis of the reviewed papers, an urgent research need on this topic arises, mainly due to the oldness of most analysed studies. Practical suggestions are given to optimise the depuration performances of lagoons: (i) application of intermittent and night aeration; (ii) reduced air flow rates; (iii) adaptation of microbial biomass to high contents of inhibiting compounds in wastewater; (iv) construction of baffles to keep the planned hydraulic retention time avoiding short-circuit; (v) integration of lagoons with other treatments (e.g., constructed wetlands); (vi) ferti-irrigation of crops with lagoon effluents rather than disposal into water bodies. • A systematic review of 36 scientific papers (reporting 63 case studies) is presented. • The efficiency of lagoons at removing organic compounds was in a wide range (25–98%). • Treatment efficiency was higher in aerated lagoons compared to non-aerated systems. • This efficiency did not depend on the type of treated wastewater. • Practical suggestions are given to optimise the depuration performances of lagoons. [ABSTRACT FROM AUTHOR]

Pit recharge systems (PRS) control odor by managing organic solids in swine manure. However, there needs to be more understanding of PRS's effect on the microbiome composition and its impact on odor formation. A study was conducted to understand how recharge intervals used in PRS impact manure microbiome and odor formation. Bioreactors dynamically loaded simulated recharge intervals of 14, 10, and 4 days by diluting swine manure with lagoon effluent at varying ratios. Treatment ratios tested included 10:0 (control), 7:3 (typical Korean PRS), 5:5 (enhanced PRS #1), and 2:8 (enhanced PRS #2). Manure microbial membership, chemical concentrations, and odorant concentrations were used to identify the interactions between microbiota, manure, and odor. The initial microbial community structure was controlled by dilution ratio and manure barn source material. Firmicutes and Proteobacteria were the dominant microbial phyla in manure and lagoon effluent, respectively, and significantly decreased or increased with dilution. Key microbial species were Clostridium saudiense in manure and Pseudomonas caeni in lagoon effluent. Percentages of these species declined by 8.9% or increased by 17.6%, respectively, with each unit dilution. Microbial community composition was controlled by both treatment (i.e., manure dilution ratio and barn source material) and environmental factors (i.e., solids and pH). Microbiome composition was correlated with manure odor formation profiles, but this effect was inseparable from environmental factors, which explained over 75% of the variance in odor profiles. Consequently, monitoring solids and pH in recharge waters will significantly impact odor control in PRS. [Display omitted] • Initial microbial community composition was controlled by barn source and dilution. • Firmicutes were the dominant phylum in manure and Proteobacteria in lagoon effluent. • Manure microbial membership was impacted by solids, pH, dilution, and barn source. • Manure properties and microbes affect odor but unraveling their roles is a challenge. • Manure solids are the key manure property to monitor and control. [ABSTRACT FROM AUTHOR]

This work concentrates on the processes of stratification and turbulent mixing in a choked shallow lagoon, Xiaohai Lagoon, by using a three-dimensional hydrodynamic model. The model results were processed to derive buoyancy frequency, shear production, gradient Richardson number, and buoyancy flux during the tidal cycles. The parameters regarding stratification and turbulent mixing exhibited significant heterogeneity within the lagoon. Shear production primarily occurred in the downstream region with complex shoreline and bed morphology, whereas stratification was predominantly developed in the flat upstream region by tidal strain and baroclinic strain, especially during the ebb tide. The salinity mixing indicated by buoyancy flux was thus mainly confined during the ebbs in the downstream region and the middle-lower layer of the upstream region. In addition, the distribution of the gradient Richardson number indicated dominances of shear instability and buoyancy effects in the downstream and upstream regions, respectively. By simulating various combinations of river discharges and offshore tidal ranges, we examined the variations of stratification and turbulent mixing within the lagoon's parameter space. The results revealed the influence of the interaction between tidal and runoff forces through a modulation of the salinity interface's moving range. Further investigation of the buoyancy balance underlying the variation in stratification revealed the dominance of straining and mixing, while advection played a secondary role. Straining dominance appeared at locations with sufficient streamwise density gradients in the upstream region during the ebb. The contribution of advection was essential, as straining and mixing largely counteracted each other's effects through their persistent competition. A conceptual model for the stratification and mixing patterns in choked lagoons during the tidal cycle was then proposed. This conceptual model clarifies the process of the interaction between stratification and turbulent mixing in the distinctive hydrological and geomorphic environments of choked lagoons and could serve as a conference for investigating other lagoon systems in the world. • Stratification, shear production, and their balance differ spatially within the lagoon. • Salinity interface's movement affects stratification and mixing intensity. • During ebbs, Straining surpasses mixing upstream with large density gradients. • Straining-mixing competition and advection contribute equally to buoyancy balance. • A conceptual model of stratification-mixing patterns in choked lagoons is proposed. [ABSTRACT FROM AUTHOR]

Engineering solutions are widely conducted to restore coastal lagoons against environmental deterioration for climatic and anthropogenic impacts. To investigate hydrodynamic responses to phasic restoration projects, Qilihai Lagoon is set as a representative object for its typical riverine and marine hydrological regimes. The numerical modelling is based on three engineering stages under real-world conditions. The numerical results demonstrate that the improvement of local connectivity strengthens tide currents, and enhances local water exchange effectively. In adjacent water areas of tidal inlet and streams, local water exchange capacity turns out to be superior because of intensive inflows. The first-stage project optimizes system-wide water exchange capacity by 43% in terms of the half-life exchange rate for dredging basin, while the system requires much more time for water exchange for excessive water volume at the second stage after removing aquaculture ponds. Moreover, based on influence mechanisms of system-wide water exchange capacity, a fast-estimation method is established by initial water volume, tidal prism and stream discharge, where flow re-entrainment and hydrodynamic effects are included. The method can be applied to optimize subsequent engineering implementations and risk managements for coastal lagoons and lagoon-like systems in a morphodynamic equilibrium state. • Impacts of phasic restoration projects on hydrodynamic characteristics are investigated. • Seasonal inflows and flow re-entrainment are considered together for coastal lagoons. • Hydrodynamic effects of riverine and tidal actions are emphasized for water exchanges. • A fast-estimation method is established for assessments on system-wide water exchange capacity. [ABSTRACT FROM AUTHOR]

Thermohaline and current variability for a certain period in the first ∼40 km off the western Yucatan Peninsula were analyzed, from five hydrographic campaigns carried out between 2017 and 2018, and 2.5 years of two moored current meters and satellite wind observations. Three different coastal environments in the study region create local particularities important to the thermohaline variations: mangrove forests, coastal lagoons, and river or groundwater discharges. The thermohaline variability presented a seasonality marked principally by the salinity balances and by the temperature heating/cooling cycles. Seawater was commonly saltier near the coast, principally in spring (dry epoch) when there is an increase in evaporation. The type of waters identified were modified versions of the Caribbean water masses, where precipitation/evaporation balances, along with the wind forcing, mixed them with the near-coastal local fluxes. Dimensional analysis showed that bottom friction was not negligible (Ek > 1), and that water column stratification constrained the flow (Ri > 1). Currents off Campeche and Sisal flowed west-southwest and showed low coherency between sites, due to the different coastline orientations. Their predominant force was the wind stress, but bottom friction affected them, supported by the Ekman surface and bottom layers intersection. Ekman surface layer was commonly deeper than the actual depth, therefore Ekman spiral cannot develop completely, hence currents had an angle to the right of the direction of the winds of 72° (42°) in Campeche (Sisal). These flows were moderately coherent and in phase with the wind stress, at periods of 5 (18) days, respectively. • Water masses over the shelf are modified versions of the Caribbean water masses. • Continental contributions and the precipitation/evaporation balances mixed them. • Currents showed low coherency between sites due to the coastline orientation. • Wind stress is their predominant forcing, but bottom friction is important. • Winds and currents flow preferentially towards the same direction. [ABSTRACT FROM AUTHOR]

During the 1970s and 2010, the population of Anguilla anguilla declined significantly, and the species is now classified as a critically endangered species by the International Union for Conservation of Nature (IUCN). Considering its social, economic, and ecological importance, it is necessary to understand the biological mechanism that controls population dynamics, in particular the passage from the resident phase to the migratory phase. During this phase of their life cycle, the environment plays a key role in the maturation of the spawners which will eventually undertake a long spawning migration to the Sargasso Sea. An assessment of the morphological characteristics of eels during their silvering process and reproductive activity was conducted by collecting 1513 female eels from seven lagoons in the North Adriatic Sea. Morphometric analyses show that eels classified as pre-migratory according to the Silver Index are histologically (65% of eels with oocytes in the most advanced stage of development) and morphologically ready to migrate. Accordingly, pre-migrant eels treated with hormone induction performed similarly to migrant eels. They mated and spawned spontaneously in the tank with a percentage of 81.0%, and 88.2% of them produced viable eggs. The results showed how the North Adriatic lagoons could present favourable conditions that permit the fast development of females with high reproductive potential. This data can be used to develop successful strategies to conserve and manage eel populations. • New achievements on knowledge in European eel biology and ecology. • Reproductive activity of pre-migrant eels is in line with migrant eels. • North Adriatic lagoons present favourable growth conditions. [ABSTRACT FROM AUTHOR]

Coastal lagoons are highly productive and biologically diverse landscape features that sustain a range of valuable natural services to societies. Acting as an interface between land and sea, they evolve naturally, but are also vulnerable to various forms of human activity. Based on old cartographic material, LiDAR elevation data, Holocene sea level histories, and shoreline modelling, we study the development of coastal lagoons on the postglacially uplifting, tideless coast of the brackish water Baltic Sea. Ecological succession of habitats along the path from bays to semi-enclosed lagoons, coastal lakes or bogs is discussed utilizing community structure analysis of habitat building bottom vegetation. There are about 600 lagoons in Estonia, but they are typically small (bigger ones up to 6 km2) and mostly <1 m deep. Due to ongoing postglacial uplift (1.5−3.4 mm/a), lagoons are just a relatively short (50−500-years long) transitional phase in a long (up to ∼10 000-years) succession. Locating at an altitude of up to 20−30 m, some older, more resilient palaeolagoons can be nowadays distinguished as lakes or bogs, while smaller ones have blended into the surrounding landscape. The contemporary lagoons are ephemeral too, because the emerging terrain has already been flattened by erosion and sedimentation. After separation from the sea, the brackish water habitat is gradually replaced with freshwater habitat and both biodiversity and plants coverage usually increases. As organic deposits build up, low-growth shores are replaced with high-growth vegetation; reedbeds expand. Detached from their marine past, communities typical for lakes, fens, bogs or forests are finally formed. As a result of eutrophication, ongoing climate change and sea level rise, the balance between emergence of new lagoons and their disappearance due to distancing and swamping has shifted over the past 100 years. [Display omitted] • Postglacial uplift is the main shaper of lagoons; barrier formation the secondary. • "Coastal lagoon" is a relatively brief phase in a long succession path. • Successional changes in habitat forming bottom vegetation are studied with ANOSIM. • Uplift driven distancing and overgrowing directs: bay – lagoon – lake – bog. • Many inland lakes and bogs up to 20–30 m altitude are palaeolagoons in Estonia. [ABSTRACT FROM AUTHOR]

Microplastic pollution has affected every region of the marine environment and every level of the food chain. The potential health risks associated with the consumption of seafood products affect the worldwide seafood industry. Crustaceans are the fastest-growing fisheries industry. However, due to their predatory feeding behavior and benthic habitats, crabs are at higher risk of consuming MPs than other marine organisms. This is especially true for blue crabs (Callinectes sapidus) who spent most of their lives in coastal environments (such as lagoons and estuaries), which are among the most burdened environments by microplastic pollution. This study evaluated the occurrence of MPs within juvenile blue crabs from Antinioti lagoon, Greece. The findings showed an average abundance of 0.28 MPs/Ind with MPs being identified as nylon and polyethylene (PE), by Raman microscopy. Hence, blue crabs are affected by microplastic pollution from the early stages of their lives. [Display omitted] • The first study to confirm the presence of MPs in blue crab juveniles. • The abundance of crab-ingested MPs was determined 0.28 MPs/Ind. • The investigated MPs were identified as Nylon and Nexar particles. • The crab-ingested MPs originated from fishing and touristic activities • The ingestion of MPs is influenced by their abundance in the water column. [ABSTRACT FROM AUTHOR]

Marine transitional environments play an important role in human sustainability. Around these ecosystems, coastal lagoons are subject to high anthropogenic pressure from population growth. The increased demand for goods and services is associated with the elevated discharge of untreated and treated wastewater into lagoon systems. The absence of benthic organisms in lagoon environments has been linked to extreme natural conditions and severe anthropogenic impact at both spatial and temporal scales. However, the mechanisms that lead to the presence of azoic sediments in lagoon environments have yet to be studied. This study aimed to determine the vertical variability of textural groups, geochemistry, and benthic foraminiferal fauna to understand how natural and anthropogenic components generate a vertical sediment sequence with low or absent benthic foraminifera in a subtropical coastal lagoon in the southwestern end of the Gulf of California. A 41 cm-long sediment core was collected from La Paz Lagoon at a 1-m depth. The core was sectioned every centimeter, and sediment subsamples were dried and homogenized for grain size, calcium carbonate, elemental and isotopic carbon and nitrogen analyses, and benthic foraminifera quantification. Muds with fine sands towards the core's base characterized the sedimentary sequence. Organic carbon and total nitrogen increased from the base (1.4% and 0.06%, respectively) to the core-top (CT, 3.0% and 0.14%, respectively), significant from the 27 cm interval. Calcium carbonate content was very low (<0.8%). The relationship of δ13C vs. C:N ratio indicated that sedimentary organic carbon was derived from the marine and sewage source mixture. The δ15N of organic matter increased by 3.7‰, starting from the 27 cm interval towards the CT. The nitrogen sewage input source was relatively more significant than nitrogen fixation. The few individuals (<18 ind. in 10 g) and genera (Ammonia and Elphidium), as well as the absence of foraminifera in 19 of 41 intervals in the core, indicated that environmental conditions were unfavorable, even for colonization of environmentally stress-tolerant genera. The frequency of azoic sediments was higher from the 25 cm interval to the CT vs. from the base to the 25 cm interval. Moreover, the AEI revealed severe to moderate hypoxia in the study area. The limited presence of benthic foraminifera and calcium carbonate preservation corroborated that the quality of the lagoon's environment has deteriorated along with population growth, which requires strategic programs to sustain this transitional ecosystem. • Muds with high organic carbon content and very low calcium carbonate. • Few individuals and only two genera: Ammonia and Elphidium in sediment core. • Absence of foraminifera in 19 of 41 intervals in the sediment core. • AEI revealed severe to moderate hypoxia in the lagoon. • Nitrogen sewage input source was more significant than nitrogen fixation. [ABSTRACT FROM AUTHOR]

Urbanization has increased the spread of antibiotic resistance genes (ARGs) impacting urban aquatic ecosystems and threatening human health. However, an overview of the antibiotic resistome in artificial coastal lagoons formed by coastal seawall construction is unclear. This study investigated the resistome of sediment in a coastal lagoon, established for over 60 years and found that the composition of the resistome in the lagoon sediments associated with the seawall significantly differed from that of marine sediment external to the seawall. Moreover, the diversity, number, relative abundance, and absolute abundance of the antibiotic resistome in the lagoon sediments were significantly higher compared to marine sediment. Network analyses revealed that more co-occurrences were found in lagoon sediment between bacterial communities, ARGs and mobile genetic elements (MGEs) than in marine sediments, suggesting that bacteria in lagoon sediments may be associated with multiple antibiotic resistances. Random forest and structural equation models showed that an increase in the absolute abundance of MGEs had a concomitant effect on the absolute abundance and diversity of ARGs, whereas increasing salinity decreased the absolute abundance of ARGs. This study provides a basis to assess the risk of resistome diffusion and persistence in an artificial coastal lagoon. • Higher abundance of ARGs in lagoon sediments due to prolonged seawall blockage. • The spread of ARGs in artificial lagoons was mainly due to horizontal gene transfer. • More co-occurrences in lagoon sediment between bacterial communities and resistome. • Increased salinity significantly reduced the absolute abundance of ARGs and MGEs. [ABSTRACT FROM AUTHOR]

Managed aquifer recharge (MAR) offers a potential innovative solution for addressing groundwater resource issues, enabling excess surface water to be stored underground for later abstraction. Given its favourable hydrogeological properties, the Pliocene sand and gravel (Crag) aquifer in Suffolk, UK, was selected for a demonstration MAR scheme, with the goal of supplying additional summer irrigation water. The recharge source was a 4.6 km drainage channel that discharges to the River Deben estuary. Trialling the scheme in June 2022, 12,262 m3 of source water were recharged to the aquifer over 12 days via a lagoon and an array of 565 m of buried slotted pipes. Groundwater levels were raised by 0.3 m at the centre of the recharge mound with an approximate radius of 250 m, with no detrimental impact on local water features observed. The source water quality remained stable during the trial with a mean chloride concentration (133 mg L−1) below the regulatory requirement (165 mg L−1). The fraction of recharge water mixing with the groundwater ranged from 69% close to the centre and 5% at the boundary of the recharge mound, leading to a reduction in nitrate-N concentration of 23.6 mg L−1 at the centre of the mound. During July–September 2022, 12,301 m3 of recharge water were abstracted from two, 18 m boreholes to supplement surface irrigation reservoirs during drought conditions. However, the hydraulic conductivity of the Crag aquifer (∼10 m day−1) restricted the yield and thereby reduced the economic viability of the scheme. Construction costs for the MAR system were comparatively low but the high costs of data collection and securing regulatory permits brought the overall capital costs to within 18% of an equivalent surface storage reservoir, demonstrating that market-based mechanisms and more streamlined regulatory processes are required to incentivise similar MAR schemes. [Display omitted] • MAR developed in a sand and gravel aquifer to augment irrigation water resources. • 12,262 m3 of water were recharged, although aquifer conductivity limited recovery. • Water quality requirements were met for storing recharge source water underground. • Capital costs for a MAR scheme were within 18% of an equivalent storage reservoir. • Market-based mechanisms needed to incentivise MAR schemes on privately owned land. [ABSTRACT FROM AUTHOR]

Coastal lagoons have long been subject to continuous changes caused by mutual interactions with human activities. Monitoring such changes becomes critical, particularly when modifications in landscape and land cover classes can affect their capacity to ensure Ecosystem Services (ESs). In the Venice lagoon, some confined areas called "valli da pesca" supply provisioning ESs, namely aquaculture and hunting, but also other ESs important for the entire lagoon, such as regulating and cultural ones. Being heavily modified ecosystems under human control, valli da pesca underwent considerable morphological evolution depending on the maximized ES and the applied management. Using remote sensing data from different sources, we reconstructed changes in land cover and landscape elements in valli da pesca over the last century. By calculating landscape indicators related to land, saltmarshes, and water, we found that landscape features were initially similar for all the valli da pesca. Then, a process began between 1975 and 1987, in which management devoted to maximizing different ESs shaped the land cover in specific patterns. This study confirms the importance of these areas in the context of the entire lagoon and suggests the need to monitor their land cover changes to avoid the depletion of their capacity to conserve landscape elements and the related ESs. In this task, remote sensing data represents an important source of historical data that can deepen the knowledge about human-Nature interactions, capable of tracing the landscape evolution and the dynamics in the ESs supply as responses to human interventions. [Display omitted] • Aquaculture and hunting reserves of the Venice lagoon changed through the years. • Remote sensing data allows for multi-temporal landscape analyses. • Landscape indicators were effective in describing the valli da pesca evolution. • Human interventions influenced the landscape structure in order to maximize different ecosystem services. • Fish production and hunting cause different landscape arrangements to arise. [ABSTRACT FROM AUTHOR]

Climate change poses challenges to agricultural water resources, both in terms of quantity and quality. As an adaptation measure, the new European Regulation (EU) 2020/741 establishes different water quality classes for the use of reclaimed water in agricultural irrigation. Italy is also working on the definition of a new regulation on reclaimed water reuse for agricultural irrigation (in substitution of the current one) that will also include the specific requirements imposed by the European one. Nature-based Solutions (NBS) can be a cost-effective and environmentally friendly way to facilitate water reclamation and reuse. The present study reports the outcomes of a long-term monitoring campaign of two NBS (e.g., a constructed wetland (CW) and a lagoon system (LS)) comparing influent and effluent concentrations of different contaminants (e.g., E. coli , BOD 5 , TSS, TN and TP) with the threshold values imposed by the new regulations. The results showed that in both the case studies, E. coli (about 100 CFU 100 mL−1) and BOD 5 (lower than 25 mg L−1) mean effluent concentration need to be further reduced in reclaimed water to be suitable for unlimited reuse. As a negative aspect, in both the monitored NBS, an increase in TSS mean concentration in the effluent was observed, up to 40 mg L−1 in the case of the LS, making reclaimed water unsuitable for agricultural reuse. The CW has proven to be more effective in nitrogen removal (the effluent mean concentration was 3.4 mg L−1), whereas the LS was better at phosphorus removal (with an effluent mean concentration of 0.4 mg L−1). Based on the results, recommendations were made to further improve the performance of both systems in order to have adequate water quality, even for class A. Furthermore, the capacity of reclaimed water to meet crop water and nutrient needs was analyzed, and total nitrogen removal rate coefficients were calculated for the design of future LSs. • NBS can facilitate water reclamation and reuse in agriculture. • Long-term monitoring gives better insight into NBS treatment performance. • Treated wastewater can contribute to meet crop water and nutrient needs. • The NTIS model can be exploited for modelling of TN removal in NBS. [ABSTRACT FROM AUTHOR]

A two-dimensional, non-linear, finite difference, hydrodynamic model was applied to the San Pedro channel (Cadiz bay) to study the changes on tidal current asymmetries along its course due to the reconnection of its main channel to a wide tidal lagoon that was artificially desiccated in the mid of 20th century. Results of both experimental in-situ data and model simulations show changes from a flood-dominance of current asymmetries when the channel was isolated, to a stronger and ebb-directed asymmetry after the reconnection to the upper lagoon. The influence of the upstream intertidal flats is revealed on the configuration of tidal current asymmetries induced by the mutual phase-lags between the M2 and M4 tidal constituents, as well as in the tide-induced residual currents. These effects were found to be stronger during spring tides. The impacts of current asymmetry reversal on the morphodynamics of coastal tidal environments and on water quality and pollutants transport are discussed. • Changes in tidal currents asymmetries are analyzed in a human-modified creek. • A real case is evaluated by field measurements and hydrodynamic modeling. • The isolation of the creek from upper marshes causes weak flood-asymmetry. • The creek re-connected to upper tidal flats presents stronger ebb-asymmetry. [ABSTRACT FROM AUTHOR]

1. Coastal lagoons are generally assumed to be naturally stressed environments. They are expected to be uniform ecosystems, dominated by r-strategist species. 2. There is increasing evidence that they are complex, with strong self-regulatory mechanisms and homeostatic capacity based on diversified trophic networks. 3. We here show a small coastal lagoon, with strong urban influences, yet with relatively complex communities enclosed in algal balls structured by Valonia aegagropila C. Agardh. 4. These balls were colonized by several algae and invertebrates living inside, constituting a biocenosis with a remarkable species richness and functional and structural diversity. 5. The results showed that the meiofaunal biomass from Valonia balls is not directly controlled by their size or total volume. Rather, the ability to produce its biomass and regulate its energy depends mainly on the characteristics of its diversity, either due to its species richness or the abundance of the fauna that inhabits this system. 6. Consequently, the biological productivity of the groups could be maintained in balance with the energy flow of the ecosystem in a context of a highly anthropized partially enclosed lagoon ecosystem. • Valonia balls harbour a biodiversity community. • These balls create a unique ecosystem in terms of biomass and productivity. • Coastal conservation actions need to consider this community. [ABSTRACT FROM AUTHOR]

The rapid decline in both quality and availability of freshwater resources on our planet necessitates their thorough assessment to ensure sustainable usage. The growing demand for water in industrial, agricultural, and domestic sectors poses significant challenges to managing both surface and groundwater resources. This study tests and proposes a hybrid evaluation approach to determine Groundwater Quality Indices (GQIs) for irrigation (IRRI), seawater intrusion (SWI), and potability (POT), finalized to the spatial distribution of groundwater suitability involving water quality indicator along with hydrogeological and socio-economic factors. Mean Decrease Accuracy (MDA) and Information Gain Ratio (IGR) were used to state the importance of chosen factors such as level of groundwater above the sea, thickness of the aquifer, land cover, distance from coastline, silt soil content, recharge, distance from river and lagoons, depth to water table from ground, distance from agricultural wells, hydraulic conductivity, and lithology for each quality index, separately. The results of both methods showed that recharge is the most important parameter for GQI IRRI and GQI POT , while the distance from the coastline and the rivers, are the most important for GQI SWI. The spatial modelling of GQI IRRI and GQI POT in the study area has been achieved applying three machine learning (ML) algorithms: the Boosted Regression Tree (BRT), the Random Forest (RF), and the Support Vector Machine (SVM). Validation results showed that RF has the highest prediction for GQI IRRI , while the SVM model has the highest prediction for the GQI POT index. It is worth to mention that the future utilization and testing of new algorithms could produce even better results. Finally, GQI IRRI and GQI POT were combined and compared using two combine and overlay methods to prepare a hybrid map of multi-GQIs. The results showed that 69% of the study area is suitable for irrigation and potable use, due to both geogenic and anthropogenic activities which contribute to make some water resources unsuitable for either use. Specifically, the northern, western, and eastern portions of the study area are in the "very high and high quality" classes while the southern portion shows "very low and low quality" classes. In conclusion, the developed map and approach can serve as a practical guide for enhancing groundwater management, identifying suitable areas for various uses and pinpointing regions requiring improved management practices. [Display omitted] • Groundwater suitability for human utilization has been assessed in the Campania region (South Italy) using a combined approach. • Three machine learning methods (RF, BRT, and SVM) have been tested to identify the areas related to potable and irrigation indicators. • The results show as almost 80% of resources are suitable for human utilization while the remaining 20% could benefit a preliminary treatment. [ABSTRACT FROM AUTHOR]

In order to meet the land use requirements of the treated wastewater from high density polyethylene (HDPE) membrane-enclosed anaerobic lagoons, the physical and chemical properties of the wastewater in an HDPE membrane-enclosed anaerobic lagoon were measured. The total nitrogen content (TN) in wastewater treated in membrane-enclosed anaerobic lagoons is 3165 and 1510 mg/L in winter and summer respectively. The wastewater can be used as liquid organic fertilizer, partly replacing chemical fertilizer. The safety dosage of the wastewater was 21.48 t/ha for rice and 9.54 t/ha for corn, respectively. Meanwhile, the wastewater has the characteristics of high salt (conductivity>16.0 mS/cm) and high organic matter content (COD>16,900 mg/kg). Therefore, the potential negative effects of the wastewater on soil salinity and pH should be assessed. 16S rRNA was used to investigate the bacterial population structure and assess potential biological risks of land use of the wastewater. The wastewater from lagoon has the least and the most bacterial abundance in summer and winter, respectively. The bacterial diversity of wastewater samples from lagoon is the most. 21 and 24 phyla were detected in winter and summer samples respectively. Clostridium is the absolute dominant bacteria in the summer water samples and the absolute dominant bacteria is Trichococcus in winter water samples. Several animal and plant bacterial pathogens such as Campylobacter , Corynebacterium , Facklamia and Erysipelothrix can be detected in the wastewater samples. More than 70% of pathogenic bacteria such as Campylobacter , Facklamia , Erysipelothrix and Acholeplasma can be removed by lagoon in summer, but only about 99% of Corynebacterium is still in the lagoon (XYH). While more than 60% of Corynebacterium , Facklamia and Erysipelothrix are not removed in winter. So the biological risk of land use of anaerobic pond wastewater needs to be considered. [Display omitted] • The treated wastewater can be land used as liquid organic fertilizer. • Caution should be exercised due to the effect of salt and low pH on soil and crops. • Recommended amount for paddy and corn field is 21.48 and 9.54 t/hm2, respectively. • Attention should be paid to biological safety of the treated wastewater. [ABSTRACT FROM AUTHOR]

Vegetation colonisation is an important process in the geomorphic development of atoll lagoon islands and understanding how plants establish may help model how these islands will respond to eustatic sea-level rise. The recent morphodynamics of two lagoon island forms, Maaodagalaa, a sand cay, and Mahutagalaa, a forested island, in Huvadhoo Atoll, Republic of the Maldives, provided an exceptional opportunity to examine processes of plant colonisation over annual to decadal time scales. Maaodagalaa sand cay migrated on the reef platform between June 2019 and February 2020 resulting in a new plant-free surface close to sea-level. During this period the new island surface was colonised by 10 species of marine-dispersed plant species. Seedlings were found across the highest surfaces formed in that period (0.62 m above local datum and 0.48 m above the highest tides recorded between 1987 and July 2020). An inundation event in February 2020 stranded debris up to 0.50 m above spring high tide, 15 m inland of the northern margin of the island. Our results indicate wave events, resulting from local, fetch-limited waves, in combination with spring high tides, can strand seeds of marine-dispersed plants on sand cays and around the margins of forested islands. Seedling survival is enhanced if seeds are stranded during peak perigean spring high tides during a local 7-month spring tide cycle. Lagoon islands in the Maldives are still being formed and colonised by plants despite local and ongoing sea-level rise. • The deposition of seeds results from a combination of wave run-up and spring high tides. • Seedling survival is related to the 7-month perigean tidal cycle in the Maldives. • Lagoon sand cays are rapidly re-colonised by plants during periods of island migration. • Sand cay colonisation does not appear to be propagule limited. [ABSTRACT FROM AUTHOR]

Phthalate esters (PAEs) due to their ability to leach from plastics, widely used in our daily life, are intensely accumulating in wastewater water treatment plants (WWTP) and rivers, before being exported to downstream situated estuarine systems. This study aimed to investigate the external sources of eight plasticizers to the largest European lagoon (the Curonian Lagoon, south-east Baltic Sea), focusing on their seasonal variation and transport behaviour through the partitioning between dissolved and particulate phases. The obtained results were later combined with hydrological inputs at the inlet and outlet of the lagoon to estimate system role in regulating the transport of pollutants to the sea. Plasticizers were detected during all sampling events with a total concentration ranging from 0.01 to 6.17 μg L−1. Di(2-ethylhexyl) phthalate (DEHP) was the most abundant PAEs and was mainly found attached to particulate matter, highlighting the importance of this matrix in the transport of such contaminant. Dibutyl phthalate (DnBP) and diisobutyl phthalate (DiBP) were the other two dominant PAEs found in the area, mainly detected in dissolved phase. Meteorological conditions appeared to be an important factor regulating the distribution of PAEs in environment. During the river ice-covered season, PAEs concentration showed the highest value suggesting the importance of ice in the retention of PAEs. While heavy rainfall impacts the amount of water delivered to WWTP, there is an increase of PAEs concentration supporting the hypothesis of their transport via soil leaching and infiltration into wastewater networks. Rainfall could also be a direct source of PAEs to the lagoon resulting in net surplus export of PAEs to the Baltic Sea. [Display omitted] • DEHP, DiBP and DBP are the main PAEs discharged to the Curonian Lagoon. • Long-alkyl chain PAEs are preferentially attached to suspended matter. • The Curonian Lagoon acts as a source of PAEs for the Baltic Sea. • Ice cover could play an important role in retention of PAEs in environment. • Effluents from residential WWTPs have a different PAEs composition compared to industrial WWTP. [ABSTRACT FROM AUTHOR]

The seasonal and interannual variabilities in the water‒air net carbon dioxide (CO 2) flux were investigated in the lower zone of the Patos Lagoon Estuary (PLE), the largest choked lagoon worldwide. The studied region experienced periods of CO 2 ingassing (outgassing) during ocean-dominated (riverine-dominated) conditions. During ocean-dominated conditions (summer/autumn), CO 2 uptake was an average of −15 mmol m–2 d–1, whereas under riverine-dominated conditions (winter/spring), CO 2 emissions prevailed, reaching an average of 22 mmol m–2 d–1. The magnitude of CO 2 uptake in summer/autumn was comparable to the CO 2 released to the atmosphere in winter/spring in the mesomixohaline zone. However, the CO 2 uptake in summer/autumn was 4-fold higher than the CO 2 released in winter/spring in the euhaline zone of the PLE. Unlike most estuarine systems, the PLE acted as a net CO 2 sink, with a net CO 2 uptake of −2 mmol m–2 d–1 during the period investigated (May 2017 to June 2021). The water‒air CO 2 exchanges are modulated mainly by the balance between continental freshwater discharge and the inflow/outflow of seawater. However, the combined effect of wind speed, biological activity, and water residence time adds complexity to understanding the carbon exchanges in this region. The higher concentration of organic matter entails the highest estuarine CO 2 concentration during autochthonous production, which indicates heterotrophy in estuarine waters. Part of this carbon produced in the estuary is likely exported to the coast, as suggested by the high CO 2 concentration in the estuary mouth. The CO 2 export from the PLE to the coastal zone appears to make the lagoon resilient to regional anthropogenic CO 2 build-up. Owing to the water‒air net CO 2 flux range associated with complex PLE biogeochemistry dynamics, further investigations as a long-term time-series program will improve knowledge of regional CO 2 exchanges in the context of climate and elucidate the role of large estuaries and coastal bays in the global carbon budget. • The lower zone of the Patos Lagoon Estuary (PLE) was an annual net CO 2 sink zone between 2017 and 2021. • The CO 2 uptake during the ocean-dominated scenario was nearly twofold higher than the CO 2 emissions under the riverine-dominated situation in the surface waters of the PLE. • Autochthonous CO 2 production dominates the carbon dynamics in the PLE. [ABSTRACT FROM AUTHOR]

In the Gulf of Lion (NW Mediterranean), fish species such as gilthead sea bream Sparus aurata , European seabass Dicentrarchus labrax , and salema Sarpa salpa show seasonal occupation of coastal lagoons, presumably as feeding grounds during their adult life stage. The role of the lagoons in these species' life cycles remains unknown, particularly with respect to their residency, space-use, and inter-annual fidelity. Using acoustic telemetry, the movements of 72 seabream, 58 seabass, and 81 salema were monitored over four years within Prévost Lagoon (Hérault Department, Occitania Region), to characterize (1) the main seasonal patterns of space use inside the lagoon and (2) their annual migrations between the lagoon and the sea. Overall, all three species were highly resident in the lagoon during the spring/summer foraging season; seabass was the only species that also displayed high residency to the lagoon throughout the winter breeding season. The three species showed differences in their space use, although they all mainly inhabited the deep lagoon centre and adjacent shellfish farms, with very small individual home ranges (mean ± SD, 0.12 ± 0.06 km2 over all species). All species showed some inter-annual fidelity to the lagoon (>43% at minimum for seabream) although these fidelity rates were probably underestimated due to fishing mortality, which is probably high during the winter breeding season. Overall, this study reveals that coastal lagoons are key foraging habitats for these species in the Gulf of Lion. The high residency and inter-annual fidelity suggest that any increase of anthropogenic pressure within the lagoon could negatively impact these fish populations. Therefore, protection of such productive habitats could be beneficial for long-term management of emblematic coastal species and the fisheries that they support. [ABSTRACT FROM AUTHOR]

Coastal lagoons and estuaries in southeastern Australia mainly occupy lowstand incised valley systems that have been impounded by post-glacial sea-level rise. Most previous research has focused on larger estuarine and deltaic systems but the Swan Lake deposits record the geomorphic evolution of a small perched saline coastal lagoon that has remained in a youthful stage of estuary infilling with very slow progradation of the bayhead delta and slow accumulation of the central basin mud facies. This can be attributed to the relatively small catchment that is covered with natural vegetation. Marine influences at the flood-tide delta have been restricted by the perched nature of the lagoon and the high wave energy on the coast that rapidly closes the entrance with sand. Comparison with other similar lagoons along the NSW coast between Sydney and Batemans Bay illustrates the general geomorphic evolution of saline coastal lagoons. Such lagoons are also very similar to small perched lagoons in South Africa and to a lesser extent with those on the east coast of South America. [ABSTRACT FROM AUTHOR]

Life history, seasonal population dynamics and spatial distribution pattern of the opossum shrimp Neomysis americana (Mysinae) were investigated during an annual cycle in the intermittently open coastal lagoon, Laguna de Rocha, Uruguay. Mysids were sampled by day with an epibenthic sled during the four seasons from January to November 2013. The study included estimates of the N. americana abundance and biomass distribution and its population structure (stages, sex ratio and size). Main environmental conditions were recorded at each period together with chlorophyll- a , and zooplankton abundance. All biotic estimations were converted to carbon units. N. americana occurred throughout the year with higher abundances in spring and its population was dominated by females. Results indicated that N. americana reproduces during all the year within the lagoon as juveniles were recorded along the sampled period with the occurrence of highest proportions in summer. Highest proportions of gravid females were recorded in spring. Wide tolerance and sustained reproduction under varying environmental conditions, as well as potential behavioural plasticity are traits prone to favour the further extension of the species to estuaries worldwide. Image 1 • Neomysis americana actively reproduced the whole year under contrasting conditions of salinity and temperature. • N. americana populations supports wide thermal and haline tolerance. • Its abundance was positively associated to salinity and water turbidity. • Preference for turbid waters may minimize mortality due to visual predators in shallow estuaries. • Its wide environmental tolerance and behavioural plasticity favour its expansion to other regions. [ABSTRACT FROM AUTHOR]

Eutrophication is a major driver of the degradation of transitional waters worldwide, especially in environments with a restricted connection to the sea, such as coastal lagoons. In recent decades, intensive agriculture and urban water inputs around the Mar Menor coastal lagoon (Western Mediterranean) have disturbed this originally oligotrophic aquatic system. The nutrient input into the lagoon has triggered its eutrophication, leading to dystrophic crises and mass mortality events for aquatic biota, transforming it into one of the most eutrophication-impacted transitional waters in the Mediterranean basin. In this study, we applied a fish-based indicator to assess the ecological quality of shallow waters under different eutrophication-mediated environmental stress scenarios (from pre-eutrophic reference periods to critical eutrophic periods), as well as to explore the role of confinement (i.e., water renewal time) and shoreline anthropogenic pressure as factors modulating the indicator response. Despite the high magnitude of the eutrophication impact on the lagoon, the ecological quality of the shallow waters decreased only slightly after the mass mortality events. The level of confinement also had slight effects on the ecological quality of the most confined shallow areas in the summer during eutrophic periods. Hence, shallow waters could play a critical role as refuge habitats, both for fish assemblages and other aquatic taxa, by buffering euxinic conditions during eutrophication processes.". In fact, shallow waters could act as critical habitats, allowing for the recolonisation of aquatic biota from more impacted areas in the lagoon. This attribute further reinforces the need to properly manage and protect the shoreline areas of transitional waters, particularly under eutrophication scenarios. • A fish-based index was applied to assess the ecological quality of the Mar Menor. • No major temporal changes were found between reference and eutrophic periods. • The ecological quality of more confined areas was particularly affected in warmer seasons. • Shallow waters buffered eutrophication-mediated impacts by providing refuge habitats. • This alternative role should be considered into coastal lagoon restoration. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is a well-known bioinvasion hotspot, with an increasing number of non-indigenous species spreading and becoming established. Among them, the blue crabs Callinectes sapidus and Portunus pelagicus have recently called the attention due to their notable ecosystem impacts but also potential economic importance. We hereby first tackled these species through interdisciplinary approaches along the Africa's Mediterranean coast (Bizerte Lagoon, Tunisia). Molecular analyses assigned C. sapidus specimens to the Lineage 1 sensu Windsor et al. (2019), while revealed uncertainties, mismatches, and low genetic distances within the P. pelagicus species complex, suggesting that multilocus or complete mitogenomes approaches are still needed to shed light on the taxonomy and distribution of these species worldwide. Replies to questionnaires and participatory monitoring confirmed the scattered literature data available and revealed that both species have already colonized the Bizerte Lagoon and showed similar distributions, although P. segnis is more abundant and is presumably sustained by the presence of nursery grounds. Awareness campaigns strongly contributed improving the level of engagement of the local community, with low catch discards and crab taste ranked as "good" to "excellent" mostly during the second phase of the project. Crab abundances significantly affected the general perception of the fishermen in considering these species as new promising fishing targets, although educational background also played a major role among the other investigated variables. As the Bizerte Lagoon hosts a wide and native biological diversity that historically sustained local communities through small scale fishery activities and aquaculture, ecosystem-based management strategies are urged ahead of the proliferation of alien species. • Molecular taxonomy revealed uncertainties and mismatches in blue swimming crabs. • Callinectes sapidus and Portunus segnis are now invading the Bizerte Lagoon. • Questionnaires and participatory approaches are highly effective in monitoring NIS. • Awareness campaigns and exchange of experiences raise the engagement in fishermen. • Ecosystem-based management is urged to tackle blue crabs in the Bizerte Lagoon. [ABSTRACT FROM AUTHOR]

The wine-making industry drives tourism and rural revitalization in several countries. Meanwhile, winemaking generates wastewater at all production stages, mainly from cleaning of equipment, floors, vessels, and bottles. This review presents a comprehensive analysis with statistical characteristics on the overall quality and generation rate of winery wastewater since 2007, identifies the technologies used by wineries in pilot- and full-scale wastewater treatment systems, and offers insights on practical wastewater treatment at small wineries. The median wastewater generation rate has been reduced to 1.58 L/L-wine, with a weekly peaking factor of 1.6–3.4 and monthly peaking factor of 2.1–2.7. Winery wastewater is acidic and of high organic strength. The organic substances are largely biodegradable and constituent concentrations do not exceed 50% inhibitory levels for biological treatment. However, the small ratios of nitrogen and phosphorus to biochemical oxygen demand indicate substantial needs to supplement nutrients for aerobic biological treatment. The frequency of processes used to pretreat winery wastewater was in the order of sedimentation > coarse screening > equalization > neutralization. The most frequently reported treatment methods were constructed wetland, activated sludge process, membrane bioreactor, and anaerobic digestion. Advanced oxidation processes have been pilot tested for polishing. The best wastewater management practice at small wineries is physical pretreatment, followed by land-based treatment systems. Covered anaerobic lagoons and underground digesters are practicable anaerobic digestion designs to reduce organic loading to land-based treatment systems. Research is needed to develop sufficient design criteria for the best practicable treatment processes and compare land-based treatment systems at pilot and full scales. • Water quality and generation rate of winery wastewater are statistically visualized. • Practical pretreatment & treatment technologies at pilot & full scale are assessed. • Winery wastewater generation rate decreased to a median of 1.58 L/L-wine after 2007. • Winery wastewater is acidic and of high strength in readily biodegradable organics. • Physical pretreatment & land-based treatment is most practicable for small wineries. [ABSTRACT FROM AUTHOR]

The coast of the Yucatan Peninsula (Mexico) has undergone numerous changes over the last century as a result of population growth, shifts in land use, establishment of industries, and storm impacts. To understand how the mollusc fauna responded to these changes over time, paleoecological studies were conducted to compare historical and modern data, and to reveal information on past environmental conditions. We analyzed mollusc assemblages in sediment cores from Río Lagartos coastal lagoon, which span the last ∼70 years. Mollusc assemblages in the sediment cores were compared to a modern inventory of Mollusca fauna, which was compiled to assess species distributions associated with multiple environmental variables. Mollusc assemblages from the sediment cores (17,089 specimens), which represent 19 bivalve and 43 gastropod species, and modern inventory datasets possess the same ubiquitous species and the same feeding guilds, i.e., groups that exploit the same food resources. Nearly twice as many species were identified in the sediment cores as in the modern inventory. This finding probably reflects the fact that the mollusc community changed through time at the core sites in response to shifting environmental conditions. Nevertheless, we encountered a number of taxa in the modern survey samples, which were absent from the sediment cores. This was probably a consequence of the limited spatial coverage of the cores and small diameter of the core barrels, which precluded sampling of large taxa. We report differences in mollusc abundance and taxonomic composition in the cores across space and time, which may be related to salinity changes in the lagoon and modifications of the nearby terrestrial environment. • Mollusc identified in sediment cores from Río Lagartos coastal Lagoon increased the total number of taxa previously registred • The number of mollusc species in sediment cores is nearly double that from the present-day inventory of taxa. • Stratigraphic shifts in sedimented molluscs assemblages revealed past environmental changes. • Mollusc species composition in sediment cores revealed differences across space and through time. [ABSTRACT FROM AUTHOR]

Migration is an important yet dangerous phase in the life of numerous animals, including the European eel (Anguilla anguilla), which migrates thousands of kilometers between its growing habitats and spawning area. The behaviors and mechanisms involved in the migration of silver eels to their spawning area have been extensively documented in rivers, estuaries and marine environments but rarely in Mediterranean lagoons, despite the high abundance of eels in lagoons. To fill this gap, we used an ARIS 1800 acoustic camera to monitor silver eel migration (escapement) in a channel that connects the Bages-Sigean lagoon (South of France) to the Mediterranean Sea. The camera was deployed over 905 days from October 2018 to April 2022 and coupled with the monitoring of 10 environmental parameters. Silver eel escapement mainly occurred in the first hours of the night, between October and December, and to a lesser extent in March and April during a few mass migration episodes. Interestingly, silver eels that escaped from October to December were mostly males, shorter than 45 cm, whereas silver eels that escaped in March and April were mostly females (>45 cm). The night migration of silver eels and their tendency to migrate in large groups is likely a strategy to limit their risk of predation. They escaped principally when the water flowed seaward, which limits their energy demand for migration. Finally, we emphasized that knowledge gaps on the behavior of males silver eels at sea need to be addressed as a priority to improve the understanding of eel ecology. [Display omitted] • Mediterranean lagoons are key but understudied habitats for European eel. • We monitored silver eel escapement from a lagoon using an acoustic camera. • Silver eel escaped from October to December and in March–April during night. • They escaped principally when the water flow was directed to the sea. • This behavior could limit the risk of predation and the energy demand for migration. [ABSTRACT FROM AUTHOR]

Coastal ecosystems are particularly vulnerable to terrestrial inputs from human-impacted areas. The prevalence of wastewater treatment plants, unable to remove contaminants such as pharmaceuticals (PhACs), leads to their continuous input into the marine environment. In this paper, the seasonal occurrence of PhACs in a semi-confined coastal lagoon (the Mar Menor, south-eastern Spain) was studied during 2018 and 2019 by evaluating their presence in seawater and sediments, and their bioaccumulation in aquatic organisms. Temporal variation in the contamination levels was evaluated by comparison to a previous study carried out between 2010 and 2011 before the cessation of permanent discharges of treated wastewater into the lagoon. The impact of a flash flood event (September 2019) on PhACs pollution was also assessed. A total of seven compounds (out of 69 PhACs analysed) were found in seawater during 2018–2019, with a limited detection frequency (<33%) and concentrations (up to 11 ng/L of clarithromycin). Only carbamazepine was found in sediments (ND–1.2 ng/g dw), suggesting an improved environmental quality in comparison to 2010–2011 (when 24 and 13 compounds were detected in seawater and sediments, respectively). However, the biomonitoring of fish and molluscs showed a still remarkable accumulation of analgesic/anti-inflammatory drugs, lipid regulators, psychiatric drugs and β-blocking agents, albeit not higher than in 2010. The flash flood event from 2019 increased the prevalence of PhACs in the lagoon, compared to the 2018–2019 sampling campaigns, especially in the upper water layer. After the flash flood the antibiotics clarithromycin and sulfapyridine yielded the highest concentrations ever reported in the lagoon (297 and 145 ng/L, respectively), alongside azithromycin in 2011 (155 ng/L). Flash flood events associated with sewer overflows and soil mobilisation, which are expected to increase under climate change scenarios, should be considered when assessing the risks posed by pharmaceuticals to vulnerable aquatic ecosystems in the coastal areas. [Display omitted] • Lower pharmaceutical concentrations were found in Mar Menor lagoon (SE Spain) in 2018–2019 than in 2010–2011. • Reuse of WWTP effluents (since 2015) has likely contributed to the observed decrease in pharmaceutical levels. • A flash flood episode in 2019 increased the presence of pharmaceuticals in the upper seawater layer. • Biomonitoring more informative than grab water regarding pharmaceutical presence in the lagoon. [ABSTRACT FROM AUTHOR]

Biodiversity is a multidimensional concept encompassing many scales of variation, originally partitioned into three components: alpha, the number of species in a single sampling unit, beta, the variation in species identities from site to site, and gamma, the overall number of species within a defined geographical area. Investigations on macrobenthic assemblages in transitional waters have been traditionally focused on alpha- and gamma-diversity, largely neglecting beta-diversity. The aim of the work was to identify patterns of variation of macrobenthic invertebrates in transitional waters from 18 different Italian lagoons (central Mediterranean) at three different scales (site, lagoon and region), combining classical and multivariate measures for partitioning diversity. Classical alpha, beta and gamma diversity were calculated, together with measures considering also relative species abundances. The highest variability of macrobenthic assemblages was observed at the intermediate scale (among lagoons), with significant variations in terms of both alpha and beta diversity. At the smallest analysed scale (among sites) the variability was mainly in terms of beta diversity, whereas at the biggest scale (among regions), the variability was mainly in terms of alpha diversity. At the intermediate scale (among lagoons) alpha diversity was influenced by the regional species pool, with one exception (Grado-Marano lagoon) where the habitat heterogeneity and beta diversity played a major role. Beta diversity, measured as variability of dispersion with Jaccard resemble measure, was consistent with results obtained with the original formulation of Whittaker. Considering alpha diversity, a different pattern of variability was observed considering relative abundances, whereas considering beta diversity, no significant differences were observed in terms of relative species abundances. The patterns of macrobenthic assemblages among lagoons in terms of both alpha and beta diversity resulted from the complex interaction of different drivers acting in a framework of geographical variability. Alpha diversity was mainly influenced by salinity, but other factors (size, confinement, trophic status and sediment composition) were likely to contribute. Beta diversity was mainly influenced by habitat heterogeneity, deriving from different environmental parameters, such as trophic condition and water confinement. Our results support the usefulness of portioning diversity in alpha, beta and gamma components, and of combining different univariate and multivariate measures of dispersion, to consider patterns of richness and relative abundances separately. [ABSTRACT FROM AUTHOR]

This study represents the first example in which benthic heterotrophic and photoautotrophic microbial communities (prokaryotes and microphytobenthos-MPB, respectively) were simultaneously investigated. To explore how they synergistically respond to multiple natural and anthropogenic stressors, in the framework of the Project RITMARE four lagoons of the Po River Delta were sampled in May 2016: two with more marine features, i.e. Scardovari (SC) and Caleri (CL), and two more directly affected by the Po River flow, i.e. Canarin (CN) and Vallona-Marinetta (MV). The abundance and structure of benthic communities were related to physical-chemical parameters i.e. grain-size, total N, total organic C, stable C and N isotopes, and synthetic organic contaminants. Stations were gathered into three distinct groups (R ansosim = 0.540 p < 0.001) according to their different physical-chemical features: outer, inner-freshwater and inner-marine sites. Contamination levels did not seem to severely affect the microbial abundances that were overall stimulated by the combined effect of high organic and nutrient loads: prokaryotes up to +42% and MPB up to +93%. Bacteria and Archaea displayed high densities at sites directly influenced by the freshwater input and anthropogenically derived nitrogen. Delta- (30.8%), Alpha- (12.8%), Gamma- (11.8%) and Beta-Proteobacteria (7.1%) were the dominant classes at all sites. For both communities, a significant inter-lagoonal (among different lagoons) and intra-lagoonal (among stations within the same lagoon) pattern was highlighted by PERMANOVA. nMDS and SIMPER analyses revealed distinct assemblages in the inner and outer parts of the lagoons. We applied a novel functional approach based on diatom life modes. At inner and outer sites, different diatom living forms developed: epipsammic (on sand) nearby the lagoonal mouths, epipelic (on mud) at the innermost sites and non-benthic forms (planktonic, tychopelagic and epiphytic) at sites directly influenced by freshwater. Distance-based Linear Models further indicated that salinity, clay and temperature were the significant drivers of the prokaryotic spatial distribution whereas clay, PAHs, PCBs and salinity best explained the MPB structure. The dominance of non-benthic diatom life modes in the more polluted lagoon (CN) suggests a negative influence of contamination on the MPB structure. Two diatom keystone species likely contribute to restore the oxic gradient in sediments frequently exposed to anoxia, allowing the subsequent microbial aerobic degradation and the recolonization of higher trophic organisms. The capacity of re-oxygenation after anoxia has important ecological and economic implications in lagoons exploited for aquaculture. • We simultaneously studied Prokaryotes and MicroPhytoBenthos in four Po River lagoons. • Organic and nutrient loads stimulated Prokaryotes (+42%) and MPB (+93%) densities. • We found significant inter- and intra-lagoonal patterns for both Prokaryotes and MPB. • Salinity, clay and temperature best explained prokaryotic spatial distribution. • Clay, PAHs, PCBs and salinity were significant drivers of MPB composition. [ABSTRACT FROM AUTHOR]

Annual-scale environmental and ecosystem changes since the mid-19th century were reconstructed in a seasonally frozen lagoon, Lake Mokoto, located along the Okhotsk Sea coast of Hokkaido, northern Japan. X-ray fluorescence (XRF) and diatom analyses of laminated sediment were conducted to determine the impact of short-term climate oscillations and anthropogenic eutrophication on the lagoon ecosystem. In this lagoon, eutrophication has progressed since the early 20th century due to deforestation and human activity in the catchment area, such as development of the cattle industry and field agriculture. In particular, the sedimentation rate of Lake Mokoto and potassium and phosphorus contents of lake sediment have increased rapidly since 1970, in association with an increase in the number of cattle. In addition, the Lake Mokoto ecosystem shows interannual and decadal cyclic fluctuations that are separate from the anthropogenic effects. Prior to anthropogenic eutrophication, the nutrient condition of Lake Mokoto showed a close relationship with the Pacific decadal oscillation (PDO). The growth of seagrass, inferred from epiphytic diatom abundance, showed a clear decadal cycle following variation in solar irradiance. [ABSTRACT FROM AUTHOR]

Seagrass decline due to a variety of stressors has been observed worldwide. In the shallow Vaccarès lagoon, Camargue, France, the dominant macrophyte species, Zostera noltei , has suffered two major declines since 1996. The first decline was well explained by salinity and turbidity variations, while the second one could not be explained by these parameters. Other stressors such as chemical contamination, eutrophication or temperature increase could be explanatory variables for this most recent decline. The aim of our study was to understand, via scientific monitoring from 2011 to 2015, the influence of chemical contamination and its possible interactions with other biological and environmental pressures, on seagrass physiology and population dynamics in the Vaccarès lagoon. Multi-contamination by organic contaminants and trace metals was detected in the water and sediments, and their concentrations often exceeded environmental standards, particularly where seagrass regression was observed. Spatial variations in biological, environmental and chemical parameters in the lagoon were investigated by co-inertia analysis, which revealed significant relationships between environmental data, more particularly between contaminants, seagrass dynamics indices and biomarkers. Seagrass dynamics indices were negatively correlated with the concentrations of some herbicides in water (2,4-MCPA and bentazon) and with trace metals in sediments (arsenic). Rhizome starch contents in winter were negatively correlated with those herbicides and with several metals (arsenic, zinc, copper) in water and/or sediments. These results suggest that environmental contamination may play a role in seagrass decline. However, complementary investigations, such as monitoring over longer periods and additional toxicity tests, are required to address the causal link between contamination and seagrass decline. [ABSTRACT FROM AUTHOR]

Abstract Coastal lagoon sediments are important for the biogeochemical carbon cycle at the land-ocean transition, as they form hotspots for organic carbon burial, as well as potential sites for authigenic carbonate formation. Here, we employ an early diagenetic model to quantify the coupled redox cycling of carbon, iron and sulphur in the sediments of the shallow Ghar El Melh (GEM) lagoon (Tunisia). The model simulated depth profiles show a good correspondence with available pore water data (dissolved inorganic carbon, NH 4 +, total alkalinity, Ca2+, Fe2+ and SO 4 2−) and solid phase data (organic matter, pyrite, calcium carbonate and iron (oxyhydr)oxides). This indicates that the model is able to capture the dominant processes influencing the sedimentary biogeochemical cycling. Our results show that sediment of the GEM lagoon is an efficient reactor for organic matter breakdown (burial efficiency < 10%), with an important role for aerobic respiration (32%) and sulphate reduction (61%). Despite high rates of sulphate reduction, free sulphide does not accumulate in the pore water, due to a large terrestrial input of reactive iron oxides and the efficient sequestration of free sulphide into iron sulphide phases. High pyrite burial (2.2 mmol FeS 2 m−2 d−1) prevents the reoxidation of reduced sulphide, thus resulting in a low total oxygen uptake (4.7 mmol m−2 d−1) of the sediment and a relatively high oxygen penetration depth. The formation of pyrite also generates high amounts of alkalinity in the pore water, which stimulates authigenic carbonate precipitation (2.7 mmol m−2 d−1) and leads to alkalinity release to the overlying water (3.4 mmol m−2 d−1). Model simulations with and without an N-cycle reveal a limited influence of nitrification and denitrification on overall organic matter diagenesis. Overall, our study highlights the potential role of coastal lagoons for the global carbon and sulphur cycle, and their possible contribution to shelf alkalinity, which increases the buffering capacity of the coastal ocean for CO 2 uptake. [ABSTRACT FROM AUTHOR]

Abstract Climate change is likely to increasingly impact estuarine fish populations. Changes in water temperature or salinity can have deleterious effects on fish growth and behaviour. A decrease in the abundance of freshwater fish in the northern areas of the Curonian Lagoon has been attributed to increased salinity of inflowing water from the Baltic Sea. Thus, this study investigated the effects of possible changes in environmental salinity and temperature on the growth and behaviour of perch (Perca fluviatilis L.). Laboratory experiments revealed that brackish water (salinity 3 and 6) has neither a negative nor a positive effect on growth rates among perch young-of-the-year, when compared to freshwater (salinity 0). In contrast, results from behavioural experiments demonstrated that perch prefer to remain in brackish water (salinity 6) when given a choice between brackish and freshwater, and in warm water (18 °C) when given a choice between warm and cold water (12 °C). For this reason, the temperature rather than the salinity of inflowing colder brackish water from the Baltic Sea will be the most likely driver of short-term changes in fish distribution in the Curonian Lagoon. Highlights • Brackish water (salinity 3 and 6) has no effect on perch YOY growth rates. • Perch prefer to remain in brackish (salinity 6) water compared to fresh (0) water. • Perch prefer to remain in warm (18 °C) water compared cold (12 °C) water. • Temperature is the driver of changes in fish distribution in the Curonian Lagoon. [ABSTRACT FROM AUTHOR]

Abstract The natural high productivity of river lagoons has always attracted human activities of high economic value such as aquaculture. Notwithstanding, these environments are also prone to contamination, excessive organic enrichment and hypoxic/anoxic events due to the synergy between natural (e.g. fluctuations of oxygen, temperature and salinity) and anthropogenic factors (e.g. accumulation of pollutants carried by the river). In order to minimize any economic loss and potential risk for human health, river lagoons are kept under surveillance by means of monitoring campaigns that rarely include foraminifera and nematoda despite their suitability as ecological indicators. In May 2016, these two assemblages were investigated within the framework of the project RITMARE in four lagoons of the Po Delta system (Adriatic Sea) in terms of taxonomic composition, biodiversity and biological traits. Dominated by a few tolerant taxa (Ammonia tepida and Haynesina germanica for foraminifera; Daptonema , Tershellingia and Sabatieria for nematoda), both assemblages seemed adapted to conditions of environmental instability mainly ascribable to natural disturbance factors rather than to anthropogenic contamination, as indicated by the DISTLM outputs. Furthermore, the stochastic occurrence of abnormal tests and the presence of numerous organisms in subsurface sediment levels confirmed a limited effect of synthetic organic compounds (e.g. aromatic hydrocarbons and polybrominated diphenyl ethers) and trace metals on foraminifera. Focusing on nematoda, the assemblage seemed more sensitive in reflecting the peculiar environmental conditions of each lagoon and the degree of confinement, as indicated by the significant intra- and inter-lagoon variability detected for the majority of the tested metrics. In particular the significantly less biodiverse assemblage dominated by r-strategist (i.e. pioneer) organisms at the inner and middle stations of Scardovari may represent the nematoda response to recent hypoxic/anoxic conditions that often occur in the inner areas of this lagoon because of its low water renewal. Both assemblages showed to be suitable for the implementation of monitoring programs; from the study of foraminifera, a relatively low chemical contamination was inferred while, from that of nematodes, recent events of oxygen deficiency were detectable. Highlights • Foraminifera and nematoda were synoptically studied in 4 lagoons of the Po Delta. • Foraminifera were scarcely impacted by organic contaminants and trace metals. • Responses to hypoxic events were detected for nematoda but not for foraminifera. • Disturbance factors were natural and mainly ascribable to lagoon hydrodynamics. • The study of both assemblages may implement monitoring actions in riverine lagoons. [ABSTRACT FROM AUTHOR]

Abstract Few organisms can live in harsh transitional waters due to highly variable and rapid changeable physicochemical conditions. Fortunately, connecting the community structure of such fauna to specific environmental parameters can be used in tracing past and recent environmental changes. Herein, we analyzed the benthic communities in the Manzala lagoon (Nile–Delta), a region very impacted by the construction of the High–Dam at Aswan, along the inshore-offshore gradient. Approx. 3000 specimens belonging to 31 species sampled in 54 sampling sites were identified. The environmental and biological data were subjected to multivariate data analyses. Hierarchical clustering and non–metric multidimensional scaling identified three biotopes along a gradient of water salinity and sediment grain–size. The epifaunal/infaunal ratio was negatively correlated with salinity (R2 = – 0.72, p < 0.01). The low salinity–stations with a high content of silt and clay sediments were dominated by deposit-feeders, opportunistic gastropods. In contrast, the suspension–feeding bivalves dominated the more saline water and sand-sized sediments (R = 0.83, p < 0.001) near the Mediterranean outlets. The general low diversity and high dominance in the lagoon indicate high environmental stress and biodiversity loss as the background freshwater species have declined and only a few opportunistic taxa have flourished. In addition, a specific salinity-range was estimated at both species and community level. The results confirm that salinity and substrate type are major determinants for the structure of the molluscan community (feeding habit and life–mode) in marginal marine environments. Consequently, the feeding habit and life–mode of the mollusks, which have a continuous and very complete fossil record, can be used as a robust indicator for paleosalinity and paleo-hydrodynamics. Graphical abstract Image 1 Highlights • The biotic/abiotic interactions in the Nile-largest lagoon were quantitatively assessed. • Molluscan feeding habit and life-mode can predict salinity and sediment grain-size and vice versa. • Epifaunal/infaunal ratio was negatively correlated with salinity and sediment grain-size. • In contrast, suspension/deposit feeder ratio was positively correlated. • A specific salinity range was estimated for every species and faunal association. [ABSTRACT FROM AUTHOR]

Abstract Short-term bioassays were conducted in Biguglia lagoon (Corsica) to study the physiological and behavioral responses of phytoplankton to N- and P-availability. Natural communities were collected in two stations representative of the two sub-basins, at three periods with contrasting environmental characteristics to address the impact of seasonal variability. These samples were separately enriched with a full N and P enrichment, and with enrichments minus N or minus P. Phytoplankton size structuration, diversity, and growth of the total phytoplankton, the micro-, nano- and ultraphytoplankton were evaluated using spectrofluorimetry, and optical microscopy. Results showed that the communities were fueled by NO 3 − in the wet periods (autumn and spring) and NH 4 + in summer. The phytoplankton communities displayed highest cell size in autumn, with high abundances of nanoflagellates, and smallest cell size in summer with a large dominance of phycocyanin-rich picocyanobacteria. Blooms of dinoflagellates also occurred during the wet periods, coinciding with high N:P ratios. The full enrichment has not stimulated phytoplankton growth in autumn, suggesting the importance of other controlling factors such as light, a possible NH 4 + inhibition or the use of mixotrophic abilities. In spring, communities have displayed single P-limitation in the northern basin and different N and P co-limitations in the southern basin. In summer, the full enrichment consistently stimulated the growth of all cell sizes. The communities showed high N and P co-limitations, which is consistent with growing observations in aquatic ecosystems, and reflects the different functional responses of phytoplankton communities to the nutrient availability. Graphical abstract Chlosrophyll a (Chl a) concentration, DIN:DIP ratio, main taxa/morphotypes, response to the full nutrient enrichment, and N- and/or P-limitation during the three bioassay periods in the two stations representatives of the Northern and the Southern basins of Biguglia lagoon. Image 1 Highlights • Freshwater inputs from the watershed strongly influenced the phytoplankton of Biguglia lagoon. • Nanoflagellates dominated phytoplankton communities in autumn and spring with high N:P ratios. • Phycocyanin-rich picocyanobacteria bloomed in the sampling in September with low N:P ratios. • Phytoplankton showed differential responses to nutrient enrichments and induced limitations. • Phytoplankton was generally co-limited by N and P, with exceptions depending on seasons. [ABSTRACT FROM AUTHOR]

Abstract Coastal lagoons are a dynamic habitat, with varying marine and freshwater inputs determining the presence and extent of stratification, and the physical and chemical environment of the epi- and hypolimnion. As a result, the biotic assemblages that thrive in such environments are a diverse mix of species, with wide ranges of tolerances. While annual succession and vertical distribution of phytoplankton assemblages in marine and freshwater ecosystems are well documented, few data are available which describe the spatial and temporal variability of phytoplankton in coastal lagoons, even though these are a protected habitat under the European Union's Habitat Directive. In this study, high frequency monitoring (HFM) of chlorophyll fluorescence (ChlF) using a vertical profiling sonde was used to describe the variation in algal biomass over six annual cycles and through the water column of Lough Furnace, a perennially stratified coastal lagoon on the west coast of Ireland. Spot sampling, and species enumeration of phytoplankton were used to confirm the patterns observed in the fluorescence data, which indicated a general pattern of increasing biomass starting in spring, and a deepening of the deep chlorophyll maximum (DCM) over the summer. Typical of a stratified system, the DCM was often situated below the surface mixed layer, in saline hypoxic water. The best predictors of daily maximum ChlF were the depth of the surface mixed layer and daily solar radiation. We conclude that HFM allows an unprecedented glimpse into the substantial variability and complexity of phytoplankton distributions, a key biotic variable. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract The sediment in Laguna de Términos, the largest and shallowest system in the Southwest portion of the Gulf of Mexico features a broad range of ecological and hydrobiological characteristics driven by annual weather cycles (dry and wet seasons), causing large salinity gradients during the wet season due to large river discharges. Four sampling campaigns were carried out during the wet and the dry seasons in 2009 and 2010 on a selection of 13 out of 35 stations. Measurements of Sediment Oxygen Demand (SOD) and nutrient fluxes at the sediment-water interface were performed using lab incubations with 15 cm diameter sediment cores. SOD fluctuated between 1327 ± 161 and 2248 ± 359 μmol m−2 h−1 for dry and wet seasons respectively. Silicate effluxes were also significantly higher during the wet seasons (89.4 ± 15.9 μmol m−2 h−1) than during the dry season (46.5 ± 11.4 μmol m−2 h−1). PO 4 fluxes were low all over the study period without seasonal trend. No significant difference was measured for DIN fluxes but there was a tendency for DIN uptake during the wet season (−2.9 ± 18.8 μmol m−2 h−1) and conversely an efflux during the dry season (24.3 ± 7.3 μmol m−2 h−1). SOD correlated to organic matter and chloropigment content of the sediments while silicate fluxes responded to enhanced chloropigments in the sediments. During both seasons, total benthic nutrient fluxes overwhelmed largely riverine inputs and benthic carbon mineralization rates approximated a significant proportion of the pelagic organic carbon production. We conclude that benthic processes in Laguna de Términos are largely driven by weather variability and that they contribute substantially to carbon and nutrient budgets in this shallow sub-tropical system. [ABSTRACT FROM AUTHOR]

Abstract Batticaloa is a large (135.5 km2), semi-enclosed, micro-tidal lagoon that formed by barrier deposits in eastern Sri Lanka and has a unique geographic position due to its tropical monsoonal climate and absence of tectonics. The recent soft bottom sediments of Batticaloa lagoon were studied on the basis of geochemistry and grain size distribution in order to interpret their characteristics and provenance. Poor to moderately sorted medium sands are the dominant sedimentary deposits for the lagoon; therefore, a medium energy condition is suggested for sediment deposition. The average silt and clay fraction of the lagoon sediments is less than 3%, indicating medium or high energy flows. Coarser deposits are restricted to channel and lagoon mouths. The scatter plots of Nb, Zr, Cr and Sc vs. Th and Cr/V vs. Y/Ni show a felsic provenance for the sediments. The normalized diagrams of major element oxides and trace elements for the regional rocks (Vijayan Complex of Sri Lanka) indicate high country rock influence for the sedimentation for the semi-enclosed setting. The enrichment and distribution of Zr, Th, Nb, Cr and TiO 2 suggest the possibility of mineral sands that are fractionated with hydrodynamic setting of the lagoon. [ABSTRACT FROM AUTHOR]

Abstract This work concerns the modelling and numerical simulation of the 3D salinity and current distribution in a very shallow Mediterranean lagoon subject to strong winds which create intensive resuspension of polluted bottom sediments. We consider wind speeds of 10 m/s and 20 m/s in the two dominant wind directions (N-NW and S-SE). This study is made for different scenarios of flow exchanges with the surrounding hydrosystems: a brackish lagoon on the North (the Etang de Berre), the Cadiere River on the East, and a brackish channel on the South (the Rove channel). The bottom shear stress (B S S) are compared to the B B S threshold given in the literature in terms of the bottom roughness. It permits to determine which kind of bottom sediments (muds and sands) will be resuspended by each wind. The bottom currents permit to predict in which direction the suspended sediments will be moved and where are the sedimentary deposit zones. It provides a guide for the specialists of remediation of the lagoon for a mechanical extraction of sediments in such zones. In addition, numerical experiments have been performed to understand how the salinity distribution depends on the flow exchanges with the two brackish surrounding hydrosystems. This new knowledge will permit the owner of this lagoon to know how to maintain efficiently the level of salinity in the suitable range. [ABSTRACT FROM AUTHOR]

Abstract Inland and coastal water bodies around the world are susceptible to eutrophication due to inputs of anthropogenic nutrients, such as nitrogen (N) and phosphorus (P). Studies related to quantification of uptake rates of these nutrients and the factors governing these rates are limited in tropical aquatic systems, leading to inadequate understanding of N and carbon (C) cycling in these environments. Here, we report the rates of dissolved inorganic N (DIN) uptake and N 2 fixation along with N isotopic composition of particulate organic matter (δ15N POM) in Asia's largest brackish water lagoon (Chilika, India). The experiments were carried out at sixteen different locations in the lagoon where NO 3 − and NH 4 + uptake rates varied from 0.004 to 1.42 μmol N L−1h−1 (average ∼ 0.51 ± 0.51 μmol N L−1h−1) and 0.19–1.76 μmol N L−1h−1 (average ∼ 1.11 ± 0.43 μmol N L−1h−1), respectively. In general, NH 4 + was preferred substrate in the lagoon as depicted from relative preference index (RPI NH4+ >1). Despite higher DIN concentrations, the lagoon showed diazotrophic activity as evidenced by considerable N 2 fixation rates at majority of stations. Preliminary calculations of the lagoon-wide N budgeting indicate N 2 fixation and atmospheric deposition to be significant sources of new N to the lagoon. δ15N POM in the lagoon ranged from 1.34 to 8.31‰ (average ∼ 3.99 ± 1.68‰) indicating contributions from marine and terrestrial sources along with N 2 fixation to the organic matter pool. [ABSTRACT FROM AUTHOR]

Abstract Aquatic macrophytes play an important role in the structure and functioning of lagoon ecosystems. We assessed the importance of biotic and abiotic environmental factors in controlling spatial patterns of charophyte occurrence and coverage in the Curonian Lagoon. The relationships among five charophyte species, abiotic and biotic environmental factors were assessed using canonical correspondence analysis and multivariate regression trees. Salinity and wave exposure were the most important environmental factors explaining the occurrence and coverage of charophytes species in the estuarine part of the lagoon. The salinity gradient restricted the occurrence of brackish water species (especially Chara baltica and Tolypella nidifica) and freshwater species (especially Nitellopsis obtusa). The occurrence and coverage of C. contraria and T. nidifica were positively associated with the wave exposure and related factors (the bottom slope and grain size of sediments). The cover of N. obtusa could be suppressed by shading and/or space limitation by dense stands of Potamogeton perfoliatus. Relatively low explained variation in the occurrence and coverage (respectively, 28 and 19%) of charophytes by environmental factors highlights the need for analysis of other important factors (e. g. chemical content of sediments, dynamics of propagule bank and herbivory), and better resolution in linking macrophyte community composition with environmental data. Highlights • Biotic and abiotic factors influence the distribution of charophytes in the lagoon. • Salinity and wave exposure were the most important explanatory factors. • Occurrence of brackish and freshwater species were restricted by salinity of 0.4. • Chara contraria and Tolypella nidifica were positively related to wave exposure. • Competitive interactions due to stands of pondweeds limited Nitellopsis obtusa cover. [ABSTRACT FROM AUTHOR]

Abstract Astronomic tides and nonlinear tidal dispersion were assessed for the Indian River lagoon system, a tropical coastal estuary (located in central east Florida) with engineered features (causeways). The four inlets, which choke the tides entering the system, together with the expansive size and shallowness of the estuary (and the associated energy dissipation) are the prominent mechanisms leading to the microtidal environment of the lagoon. Inside the shallows, there are 12 causeway abutments that cause a compartmentalization of the waters into separate basins, whereby the causeway openings act mechanistically as acceleration-inducing throttles to promote local regions of high kinetic energy (velocities). The causeways lead to a furthered decay of tidal amplitudes, phase lags in the tides and an enhanced generation of harmonic overtides and tidal residuals relative to the natural domain (i.e., fully open—no causeways). Numerical modeling of astronomic tidal flows (Advanced Circulation—ADCIRC) employed an unstructured, triangular mesh that resolved the entire scale of the lagoonal system with element sizes of 10–100 m and captured its many intricate domain features, including: the causeways in Indian River lagoon proper and Banana River lagoon; over 150 km of sinuous channels in Mosquito lagoon; and the hydraulic connections of the individual lagoons—one of which, Haulover Canal, is only 55 m wide. The model performed well with an index of agreement of (on average) 94% when compared with tidal data from 23 stations located throughout the system. Tides in the shallows are small at just millimeters in range; the model captured the tidal signal at the stations located there with an index of agreement of (at worst) 79%. Considering previous tidal studies of the Indian River lagoon system and tropical coastal estuaries in general, this level of domain definition and model validation of astronomic tide behavior is unprecedented and provides a benchmark for numerical simulation of lagoonal tidal flow. [ABSTRACT FROM AUTHOR]

Abstract Foz do Almargem and Salgados are two small, intermittently closed and open lakes and lagoons (ICOLLs) located in the Portuguese southern coast, both remaining isolated from the sea throughout great part of the year. Based on environmental and biotic parameters, the first lagoon was classified as mesotrophic, with a greater marine influence, while the second one was classified as hypereutrophic. The plankton relations and seasonal variation were examined in both lagoons aiming at understanding the biological patterns here present and relating them with the environmental conditions, as well as inferring possible top-down or bottom-up control in the communities, determining also in which alternative trophic state they are: a clean water lagoon, with submerged macrophyte vegetation; or a turbid water lagoon, with only phytoplankton as primary producer. The plankton community greatly differs in the two lagoons. Salgados lagoon presented extremely high concentrations of phytoplankton, which form blooms throughout the year, mostly composed by potential harmful organisms. This lagoon also had very high densities of zooplankton. Phytoplankton and zooplankton density was always lower in Foz do Almargem. Rotifera, Ostracoda and Cladocera dominated the Zooplankton community in Salgados. In Foz do Almargem, Rotifera also dominates, together with other groups, such as annelids, crustaceans and mollusks larvae, which denotes a stronger marine influence. In both lagoons, organisms with body size inferior to 100 μm mainly composed the zooplankton. In Salgados lagoon, excess nutrient load induced a high density of phytoplankton, which is utilized by a high density of zooplankton, following a bottom-up control model. The lagoon clearly showed a permanent turbid-water alternative state due to excess nutrients. On Foz do Almargem, the frequent openings of the inlet throughout the wet season caused strong physical disturbance, which prevented the development of a stable planktonic community. Highlights • Foz do Almargem and Salgados are two ICOLLs that remain isolated from the sea part of the year. • The first lagoon is mesotrophic, while the other is hypereutrophic. • Salgados is in a permanent turbid state, with characteristics of bottom-up control. • In Almargem, the frequent openings of the inlet cause strong physical disturbance. • These disturbances prevent the development of a stable planktonic community. [ABSTRACT FROM AUTHOR]

Abstract Brackish lagoons, on the edge between marine and freshwater ecosystems, are vulnerable aquatic environments that act as nursery grounds for several of the most commercially exploited fish families. We used long-term passive gear data, to investigate whether the moon and tides affected fish movement between inner and outer habitats in a Northern Mediterranean coastal lagoon. In particular, we used multivariate, threshold and non-linear correlation analyses to explore the relationship between fish catches and moon and tide variables in transitional habitats, accounting for the presence of potential prey and other major temporal and environmental variables. Fish movements between habitats were influenced by moon and tide factors, which had effects comparable to annual and seasonal variations, respectively. Overall, the magnitude of effects related to the moon parameters were smaller than most environmental parameters examined, but still larger than e.g. the presence of invertebrate prey (lagoon shrimp) or some of the tide factors. European flounder catches were positively correlated with disk illumination, while sand and black goby were influenced by the moon phase. Other benthic and pelagic species showed no significant correlation. Tide direction affected negatively the movement of boxlip mullet and tide amplitude prior to sampling had far more effect than tide amplitude during sampling. Water temperature, salinity and the presence of invertebrate prey (grey shrimp) had significant but contrasting effects on some, but not all, of the species examined. Ultimately, this information could improve the understanding of the drivers in these ecosystem as well as potentially provide useful insights for improved fisheries management. Highlights • Juvenile fish movement in a brackish lagoon were influenced by moon and tide factors. • Moon and tide factors had effects comparable to annual and seasonal variations, respectively. • The magnitude of moon effects was smaller than most environmental parameters examined. • Some of the tide effects were smaller than moon effects. • Water temperature, salinity and invertebrate prey had significant but contrasting effects. [ABSTRACT FROM AUTHOR]