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Abstract: The effects of tidal flushing on the abundance, productivity, and community structure of phytoplankton in response to eutrophication were examined every 2–3 months for more than 2 years in Tapong Bay, a tropical lagoon with only 1 tidal inlet connecting it to the sea in southern Taiwan. Water flushing time ranged from 4–12 d (8–25% d-1) in the outer region subject to fast flushing to 8–24 d (4–12% d-1) in the inner region subject to poor flushing. Chlorophyll a, cell number, and gross production (GP) rate of phytoplankton were significantly greater in the inner region than in the outer region. However, while GP rate was normalized by chlorophyll a (PB) and was expressed as photosynthetic intensity, no significant differences were detected among the study sites. These parameters exhibited a unimodal seasonal pattern across all study sites, with greater values in summer and lower values in winter. No significant differences in species richness or Shannon–Wiener diversity were detected among the study sites. Nevertheless, diversity indices were significantly higher in winter and lower in summer. Classification of phytoplankton communities showed that the grouping patterns were primarily determined by sampling time. Ordination by non-metric multidimensional scaling (MDS) revealed a clear temporal continuum of changes in species composition across all study sites, suggesting that the communities were primarily structured by time, but that it was little affected by study site. Analyses of similarities (ANOSIM) showed that phytoplankton communities sampled in winter could be separated from those in summer, but others were barely separable at all. In summer, the most frequently observed species were the diatom Skeletonema costatum and the cyanobacterium Oscillatoria sp., and these shifted to the diatoms S. costatum and Cylindrotheca closterium in winter. Our results suggest that tidal flushing is an important factor for regulating responses of phytoplankton abundance and productivity to eutrophication in tropical lagoons, but the community structure was little affected due to horizontal mixing by the tidal circulation. [Copyright &y& Elsevier]

Abstract: Current distribution of Atherina lagunae poses an interesting biogeographical problem as this species inhabits widely separate circum-Mediterranean lagoons. Statistical analyses of 87 biometric parameters and genetic variation in a portion of the cytochrome b gene were examined in four populations of A. lagunae from Tunisian and French lagoons. The results suggested a subdivision into two distinct Atherinid groups: one included the French lagoonal sand smelts and the second included the Tunisian ones. Tunisian lagoonal sand smelts were distinguished from the French ones by the lower number of lateral line scales, vertebrae, pectorals and first dorsal fin rays and the higher number of lower and total gillrakers. In addition, A. lagunae from Tunisian lagoons are characterised by short preorbital length, developed operculum, broad interorbital space, larger head, robust body and a relatively small first dorsal fin which is positioned backwards. In addition, intraspecific sequence variation in a portion of the cytochrome b gene was examined in 87 individuals from Tunisia and France. The high correlation between the results of the molecular phylogenetic tree and biometric statistical data analysis suggested that two different sibling species or at least sub-species or semi-species have colonised the lagoons. In addition, our analyses suggested that the evolution of A. lagunae probably occurred in two steps including marine sympatric speciation within the large Atherina boyeri complex and a post-Pleistocene colonisation of the lagoons. [Copyright &y& Elsevier]

Mangrove ecosystems may be a source of organic carbon and nutrients to adjacent coastal systems on one hand and provide a sedimentary sink for organic carbon on the other. The balance between these two functions may be sensitive to both natural and anthropogenically induced variability, yet these effects have not been thoroughly evaluated in mangrove ecosystems. We determine organic matter sources and carbon burial rates over the past 160 years in three lagoons on the Yucatan Peninsula, Mexico. Carbon isotopes and C/N elemental ratios are utilized to trace the three sources contributing to sedimentary organic matter, mangroves, seagrasses and phytoplankton, while nitrogen isotopes are used to elucidate potential post-depositional biogeochemical transformations in mangrove lagoon sediments. All three organic matter sources contribute to organic carbon burial. Phytoplankton and mangroves are the dominant sources of organic matter in lagoon bank sediments and seagrasses are a significant source to central lagoon sediments. Organic carbon burial rates are higher at the lagoon fringes, where mangrove vegetation dominates, than in seagrass-dominated mid-lagoon areas. A reduction in mangrove contribution to the sedimentary organic matter pool concurrent with reduced total organic carbon burial rates is observed in the recent past at all three lagoons studied. Natural cycles in sediment organic matter source over the past 160 years are observed in a high-resolution core. These fluctuations correspond to climatic variability in this region, as recorded in deep-sea foraminiferal assemblages. Additional work is required in order to differentiate between recent anthropogenic perturbations and natural variability in organic carbon sources and burial rates within these ecosystems. [Copyright &y& Elsevier]

The Vaccarès Lagoon (Camargue Biosphere Reserve), a complex brackish ecosystem, is the natural habitat for numerous freshwater, marine and euryhaline species forming a particularly intricate food web. The main objectives of this study were to describe its trophic relations and investigate factors influencing its structure and dynamics. The combined stable C and N isotope method was used to establish a quantitative assessment of the trophic status of Vaccarès organisms. Although the levels of δ15N and δ13C showed large intraspecific and interspecific variations, the isotopic signatures of the species assessed revealed a general trend of 15N enrichment with trophic level. Distribution of the biota into four trophic compartments—depositivore, zooplanktivore, predator, and top-predator—was corroborated by the general analysis of the relationship between δ13C and δ15N. Analysis of seasonal and annual isotopic variations showed that natural environmental changes (increase in food abundance, climatic and salinity variations) as well as individual metabolic capacities would affect the relative stability of an organism''s trophic position. No significant correlation was found between isotopic variation and size and growth in fishes except for the eel population where the positive correlation between these two parameters confirmed intra-population trophic variations. Finally, separately examined species exhibited significant, although incoherent, correlation between their isotopic signature and lipid content. This study confirms the efficiency of the isotopic approach in trophic studies and highlights the need for further investigations of anthropic environmental modifications occurring in this protected area and frequently disturbing its food web. [Copyright &y& Elsevier]

We measured benthic and water column fluxes in a hypersaline coastal system (Baffin Bay, Texas) in 1996–1997, a period of decreasing salinity (increased freshwater input) and turbidity. Salinity decreased from a mean of 60 to 32 practical salinity units (psu) and turbidity decreased from a mean of 78 to 25 NTU over the study period. Associated with hydrological changes, there were important changes in nutrient fluxes and metabolism. There was a shift of total respiration from the water column to the sediments and an increased amount of the benthic metabolism (2–67%) was attributed to sulfate reduction in this system when salinity was lowest, perhaps a consequence of increased benthic light levels and photosynthetic production of labile carbon in the sediments. The sediments were a large sink for both N and P. Sediment particulate C:N (9.8) and C:P (119) ratios were lower than those in the water column. However, ammonium:phosphate fluxes increased coincident with increased sulfate reduction rates and porewater sulfide concentrations. Efficient N-retention mediated through dissimilative nitrate reduction to ammonium, and high rates of N-fixation in shallow, hypersaline systems may facilitate transitions from N-limitation to P-limitation. During the most hypersaline period, seston exhibited some of the most extreme nutrient ratios ever reported for a marine ecosystem (C:N 10–37 and C:P 200–1200) and suggest that plankton are likely to be P-limited or are very well adapted to low P availability. When salinity and N:P and C:P ratios were highest, the plankton was dominated by a brown tide alga (Aureoumbra lagunensis), supporting evidence that this organism is adapted to low P, long residence time systems. [Copyright &y& Elsevier]

The fish and macro-crustacean community of the Vaccare`s lagoon (Rhoˆne River delta, South France) was sampled monthly from 1993 to 2002. The lagoon salinity shifted from 15 in 1993 to 5 in 1994–1997 and went back to 15 in 1999–2002. Connections with the sea also varied during the study period with larger openings in 1996–1997. During the study period, the community changed to revert in 2002 to a state similar to 1993. These changes consisted of a sequence of increased and decreased patterns of freshwater species and some marine species. Typical lagoon species tended to resist to salinity changes. Freshwater species colonised the lagoon when the salinity was low. Marine species may have varied both in relation to connections with the sea and to indirect effects of freshwater outflow. This study shows that community changes following environmental variations can be delayed in time, and emphasises the need for long-term studies. [Copyright &y& Elsevier]

The horizontal and vertical variation of ichthyoplankton assemblages in continental shelf waters of the Southern Gulf of Mexico was studied during an annual cycle (1994–1995) at 22 stations distributed across four transects located off the main fluvio-lagoon systems of the area. Samples were collected from five levels of the water column, from the surface to a depth of 105 m. The Bray–Curtis Dissimilarity Index identified five assemblages: Coastal, Inner Neritic, Outer Neritic, Oceanic and a Transition Group. The main species of each assemblage reflected the habitat, season, and spawning area of adult organisms. The Coastal Assemblage occupied the uppermost water column levels of the most nearshore stations. The Oceanic Assemblage was restricted to the deepest samplings of the stations of the outer shelf and the Neritic Assemblages were located on the continental shelf between the Coastal and Oceanic Assemblages, embracing all the sampling levels in some periods. Variation in composition, location and abundance of larvae in each assemblage was determined by a series of physical processes that act at different temporal and spatial scales, especially the mixing process generated by the wind stress and continental water discharges acting at a mesoscale that influences the distribution of the assemblages along the whole continental shelf as well as a fine scale affecting the composition and vertical distribution of organisms in a more reduced area of just tens of meters in the water column. Canonical Correspondence Analysis revealed that the depth of the sample, the potential energy, and the temperature generated the greatest variability in the system. Vertical and horizontal salinity gradients play a determinant role in delimiting the Coastal and Neritic Assemblages. [Copyright &y& Elsevier]

Dzilam Lagoon, located in the central coast of Yucatan, Gulf of Mexico, is a shallow water body with average depth of 0.6 m and area of 9.4 km2. Numerous groundwater inputs are distributed along the system representing a continuous source of nitrates and silicates. Due to scarce anthropogenic activity, it is well preserved. Such pristine conditions suggest that changes on nutrient dynamics are mostly related to natural behavior. Monthly samples were taken from September 1998 to August 1999. Physicochemical parameters, inorganic nutrients and chlorophyll-a were measured in nine stations. A multivariate analysis showed salinity gradient and nutrient concentration as the most significant variables in describing lagoon hydrologic heterogeneity. On the basis of those critical parameters, classification analysis of Dzilam Lagoon identified three hydrological affinity zones (HAZ); East and West Zone characterized by higher water residence time and lower salinities during the rainy season; Central Zone with lower residence time and lower inorganic nutrients concentration. Dzilam Lagoon was a NO3− sink and a net source for NO2− and NH4+. Soluble reactive phosphorus was slightly defined and soluble reactive silica was close to conservative condition. [Copyright &y& Elsevier]

Six synoptic sampling events were conducted in the Indian River Lagoon (IRL) between April and June, 1997 to collect TSS (total suspended solids), color (dissolved organic matter), chl a (chlorophyll a), and light (photosynthetically active radiation (PAR)) data. These data were used to develop our understanding of light attenuation dynamics in the IRL and for verification of a numerical light model.Data from our study show that tripton (non-algal particulate matter calculated from TSS and chl a corrected for pheophytin) has a dominant effect on light attenuation in the IRL. For each synoptic event, there exists a positive correlation between the event-averaged downwelling light attenuation coefficient, Kd(PAR), and event-averaged tripton concentration. A negative correlation is found between the event-averaged Kd(PAR) and the event-averaged color, while a positive correlation is found between event-averaged Kd(PAR) and event-averaged chl a concentration. The correlation between event-averaged tripton and event-averaged Kd(PAR) is the only one of the three to show significance at the 0.05 level. Relative contributions of color, chl a, and tripton to light attenuation were found to be 5–25%, 10–26%, and 59–78% of Kd(PAR), respectively. These values depend on the method for partitioning Kd(PAR) and the method for obtaining average value of relative partitioned Kd(PAR) from all the data points. These values show that tripton has a more dominant influence on light attenuation in the IRL than in Tampa Bay and Charlotte Harbor, but comparable to that in Florida Bay. The effect of suspended chlorophyll on light attenuation in the IRL is less than that in Tampa Bay, comparable to Charlotte Harbor, but more than that in Florida Bay.A numerical process-based light attenuation model has been developed to calculate Kd(PAR) based on measured or simulated values of TSS, color, and chl a. The model was found to give reasonable estimates of Kd(PAR) throughout the IRL. [Copyright &y& Elsevier]

Lagoa de Araruama in the state of Rio de Janeiro, Brazil, is a hypersaline lagoon with salinity varying spatially from 45 to 56. We collected water samples during monthly cruises throughout the lagoon, and along the streams feeding the system, from April 1991 to March 1992. Nutrients and other water quality parameters exhibited great spatial and temporal variations. Mass balance calculations indicate large amounts of anthropogenic nutrient inputs. The data indicate that the lagoon currently is oligotrophic but is in a state of transition to become a mesotrophic system. Molar dissolved inorganic nitrogen:dissolved inorganic phosphorus (DIN/DIP) varied between 2.2:1 and 659:1 with a volume-weighted average of 22:1. The high DIN/DIP ratio contrasts with that found in nearby lagoons, suggesting that phytoplankton primary production is limited by phosphorus in Lagoa de Araruama. The major loss of DIP is apparently driven by biological assimilation and diagenic reactions in the sediments. Calculations indicate that the lagoon is slightly net autotrophic at +0.9 mol C m−2 yr−1. This suggests that the biomass of the primary producers is restricted by phosphorus availability. Phosphorus retention in the sediment and the hypersaline state of the lagoon prevent changes in autotrophic communities and the formation of eutrophic conditions. [Copyright &y& Elsevier]

The Huizache–Caimanero coastal lagoon complex on the Pacific coast of Mexico supports an important shrimp fishery and is one of the most productive systems in catch per unit area of this resource. Four other less important fish groups are also exploited. In this study, we integrated the available information of the system into a mass-balance trophic model to describe the ecosystem structure and flows of energy using the Ecopath approach. The model includes 26 functional groups consisting of 15 fish groups, seven invertebrate groups, macrophytes, phytoplankton, and a detritus group. The resulting model was consistent as indicated by the output parameters. According to the overall pedigree index (0.75), which measures the quality of the input data on a scale from 0 to 1, it is a high quality model. Results indicate that zooplankton, microcrustaceans, and polychaetes are the principal link between trophic level (TL) one (primary producers and detritus) and consumers of higher TLs. Most production from macrophytes flows to detritus, and phytoplankton production is incorporated into the food web by zooplankton. Half of the flow from TL one to the next level come from detritus, which is an important energy source not only for several groups in the ecosystem but also for fisheries, as shown by mixed trophic impacts. The Huizache–Caimanero complex has the typical structure of tropical coastal lagoons and estuaries. The TL of consumers ranges from 2.0 to 3.6 because most groups are composed of juveniles, which use the lagoons as a nursery or protection area. Most energy flows were found in the lower part of the trophic web. [Copyright &y& Elsevier]

The non-linear tidal interactions in the narrow, shallow coastal lagoon Yavaros Bay are investigated using a vertically integrated two-dimensional numerical model. The model sea surface elevations and currents are validated by comparison of computed tidal harmonics against those derived from harmonic analysis of the sea surface and current time series. Calculations show that tides become mixed, mainly semidiurnal in the lagoon. MK3, MS4, and M4, generated by advection and non-linear continuity, are the most energetic shallow water constituents. A large, half-basin clockwise eddy was found, whose source of energy is the M2 tidal energy flux. The size of the shoal where the eddy occurs is almost the same as the maximum tidal excursion length (∼3 km). [Copyright &y& Elsevier]

In a recent study of the mesotidal Ria Formosa, a coastal lagoon in southern Portugal, water temperature in the channels ranged from 12 °C in winter to 27 °C in summer and salinity from 13 to 36.5, although much higher values were observed in saltpans. Conditions in the Ria Formosa were not homogeneous despite a large tidal exchange of water; the inner channels of the Ria Formosa were brackish in winter but hypersaline in summer. Water in inner areas of lagoon had significantly different temperature and salinity characteristics compared to the inflowing coastal water, both in winter and in summer. Areas with these differences in temperature and salinity were detectable both at low water and at high water neaps. Deterioration of water quality is therefore more probable in these areas. The waters went through a complex heating and cooling cycle in summer with diurnal difference of ∼6 °C and 2 in temperature and salinity, respectively. The lack of freshwater input and high insolation meant the outflowing water of the lagoon was more saline that the inflowing coastal waters. In summer, the temperature controlled density with the least dense waters also being the most saline, whereas in winter salinity was the major density controlling parameter. The effects of these freshwater inputs were localised to the vicinity of the Gila˜o River. No evidence was found of persistent or widespread temperature or salinity stratification in the Ria Formosa and so this shallow lagoon appears to be vertically well mixed. Vertical mixing does not allow a dense, stagnant, bottom layer of water to form that would aggravate a deterioration of water quality. The net effect of these processes is a parcel of water that moves through the lagoon with minimal dilution and potentially receiving waste discharges. [Copyright &y& Elsevier]

We generated photosynthesis–irradiance (P–E) and phytoplankton absorption data for a coastal lagoon of northwestern Baja California. This was done for different seasons and tidal conditions. Using the vertical attenuation coefficient of light we partitioned the lagoon into two regions to run the 14C incubation experiments: an outer and an inner region. Since there is substantial variability within data sets, we conclude that it is not possible at this time to predict fine time-and-space scale variations in photosynthetic parameters. For simple primary production models, we recommend working averages for each of the two regions. There were no significant differences of the photosynthetic parameters average values for the same region and for different tidal conditions or seasons. The mean and standard error for the assimilation number were 14.6 and 2.6 mg C mg Chl−1 h−1, for the outer region, and 7.7 and 1.8 for the inner region, respectively. The mean and standard error for the initial slope were 0.036 and 0.008 mg C mg Chl−1 h−1 (μmol quanta m−2 s−1)−1, for the outer region, and 0.019 and 0.005 for the inner region, respectively. Average values of maximum photosynthetic quantum yield were 0.082 and 0.053 mol C (mol quanta)−1, for the outer and inner regions, respectively. Its standard error was the same for both regions (0.012). These average values should be used only for non-El Nin˜o years. [Copyright &y& Elsevier]

Grazing of the copepods Acartia clausi and Pseudodiaptomus hessei on natural particles was studied from on board experiments during several 24 h time series performed between 1993 and 1997 in four sites of the Ebrie´ Lagoon (Coˆte d'Ivoire). Ingestion rates of both species increased linearly with food concentration until a concentration threshold (5.5×109 μm3 l−1 for A. clausi and 5.2×109 mm3 l−1 for P. hessei) beyond which the relation presented a plateau. Both species poorly selected the peak of available particles (range 3–6 mm equivalent spherical diameter, ESD) but A. clausi seek preferentially smaller particles (6–21 μm ESD) than P. hessei (9–33 μm ESD). When the proportion of the preferred particles in the food offered decreased, A. clausi extended its selectivity towards both smaller and larger particles whereas P. hessei extended its selectivity towards larger particles only. As a consequence of these patterns, the useful particle concentration (UPC) was higher for A. clausi than for P. hessei. In addition, the ratio of the UPC for the two species showed a positive relationship with the ratio of their respective biomass. The significance of these results for the adaptation capacities of the two species and for the ecosystem functioning are discussed. A. clausi which is more suited than P. hessei to exploit smaller particles (3–6 μm) which dominate the seston, has a food competitive advantage. The inadequacy between the seston food-size composition and the selective patterns of the two main zooplankton species of the Ebrie´ Lagoon explains that they could be food limited despite the high trophic level of the lagoon. It could also partly explain the low transfer efficiency between phytoplankton and zooplankton in this ecosystem. [Copyright &y& Elsevier]

Examines the influence of bottom water hypoxia on manganese, iron and sulfur biogeochemistry in sandy sediment from the shallow coastal lagoon, Fællesstrand, Denmark. Description of the organic-poor sediment, which experiences occasional coverage of floating macroalgae and variable degrees of hypoxia at the sediment-water interface, resulting in dramatic changes in metal behavior; Metal reduction-oxidation cycles; Presence of Mn and Fe pools in sediment.

The distribution biomass and photosynthesis of three species of rooted macrophytes, Ruppia cirrhosa (Petagna) Grande, Potamogeton pectinatus L. and Zostera noltii Hornem and a floating macroalgaChaetomorpha linum Ku¨tz, were studied in Buda lagoon (River Ebro delta, NE Spain) during spring (May), summer (July) and autumn (October) 1995. Buda lagoon was characterized by a marked gradient of conductivity due to freshwater discharges from rice fields from June to October and by seawater input due to the regression of the delta of the River Ebro during the last 10 years. A typical spatial distribution was observed: monospecific stands of P. pectinatus developed near freshwater inputs in the inner part of the lagoon and mixed stands of R. cirrhosa and P. pectinatus developed in transitional zones between freshwater and seawater influence. The part of the lagoon where the influence of seawater was highest was covered by dense mixed stands of Z. noltii, R. cirrhosa and C. linum. Maximum biomass and production of P. pectinatus were reached in July (biomass of 501 gDW m−2, and maximum photosynthetic rates, Pm, of 14 mgO2 g−1 DW h−1 ). Maximum biomass of R. cirrhosa and Z. noltii (456·5 and 250 gDW m−2 respectively) and photosynthetic rate of R. cirrhosa (23·9 mgO2 g−1DW h−1) occurred in May, whereas no significant differences in production were detected between May and July in Z. noltii. Maximum C. linum production was reached in October (5·4 mgO2 g−1DW h−1). In OctoberP. pectinatus coverage and production decreased, which was related to high turbidity and density of benthivorous fish due to freshwater inflows. Implications of lower freshwater inflow and higher seawater intrusion in the spatial distribution of aquatic macrophytes in this coastal lagoon are discussed. [Copyright &y& Elsevier]

Phytoplankton dynamics in the Indian River Lagoon was examined from the point of view of several key controlling factors, including: nutrient limitation, light availability, temperature, wind, hydrodynamic restriction and grazing. Water was collected at eight sampling sites in the lagoon on a monthly basis for a two and a half year period. Samples were analysed for nutrient content and phytoplankton abundance. Site measurements of salinity and light extinction were made at all sites. Regional data on rainfall, wind and water temperature was obtained for correlation analyses. Bioassays were performed to determine nutrient limiting status and a series of preliminary grazing experiments were carried out on selected samples. The results indicate that the Indian River Lagoon is a nutrient-rich environment where phytoplankton standing crops are often held below their potential by several key loss functions, including hydraulic flushing and grazing. Spatial patterns of phytoplankton abundance generally reflected the degree of restriction to water turnover in different regions of the lagoon, with higher mean abundances in restricted regions. Spatial and temporal patterns of nutrient content and limitation suggest that patterns of external nutrient loading also play a significant role in phytoplankton dynamics. High phosphorus levels in the southern portion of the lagoon contribute to the predominance of nitrogen limitation in the region. In contrast, relatively high N/P ratios in the northern portions of the lagoon contribute to greater potential for phosphorus limitation of phytoplankton growth. As might be expected from the subtropical location of the lagoon, temporal patterns of phytoplankton abundance appear to be less strictly dependent on season than in temperate habitats, and more closely linked to variations in weather conditions, like rainfall (including storm events). The latter considerations bring into play issues like temporal variation in salinity and wind-induced mixing. The high light flux and shallow depth in the lagoon also presents the potential for photoinhibition. [Copyright &y& Elsevier]

Recruitment patterns of crabs and other benthic invertebrates with planktonic larvae are determined by a combination of pre- and post-settlement factors. Recruitment is considered settlement limited when there is a positive correlation between the postlarvae available in the water column and the number of recruits, and regulated when abundance of individuals is mainly affected by post-settlement factors, such as competence and inter or intraspecific predation. Temperate southwestern Atlantic saltmarshes are inhabited by Cyrtograpsus angulatus and Chasmagnathus granulata, two intertidal grapsid crabs. These crabs are considered key species in the ecosystem in Mar Chiquita coastal lagoon, Buenos Aires, Argentina. In this work, we compare the recruitment pattern of Cyrtograpsus angulatus and Chasmagnathus granulata on the basis of a 3-year sampling programme. Furthermore, we examine experimentally, in laboratory and field, settlement and postsettlement processes that can help explain these patterns: habitat selection, intra- and inter-cohort cannibalism and predator avoidance behaviour. Finally, we integrate our results with the previous knowledge about distribution, growth and reproductive biology of both species, to propose a model of recruitment of each species. Both species had a consistent recruitment pattern through 3 years. Recruitment of both species started at the beginning of summer, and continued to autumn, but recruits were present until the beginning of spring. Densities of recruits and juveniles of C. angulatus were not correlated, whereas, there was a relationship between abundance of recruits and juveniles of C. granulata. In the field, recruits of C. angulatus suffered high mortality caused by intra- and inter-cohort cannibalism. Megalopae of C. angulatus selected a substrate (crevices inFicopomatus enigmaticus reef) that gave them refuge against cannibals. First crabs of C. granulata selected adult conspecific substrate (mud from adult habitats). Recruits of C. angulatus avoided adults of either species. A qualitative model of recruitment of both species is proposed. Post-settlement processes strongly affects the recruitment pattern and, consequently, both species have regulated recruitment. The degree of such regulation, however, is more intense in C. angulatus than in C. granulata. [Copyright &y& Elsevier]

Biogeochemical processes and budgets of carbon, nitrogen and phosphorus from the semi-enclosed Chiku Lagoon were constructed through periodic observations and modelling. During the investigation, samples were mostly collected bimonthly, and hydrochemical properties, inorganic and organic nutrients (DIN, DON, DIP, DOP, Dsi (dissolved silica)) and organic carbon (DOC, POC) from waters associated with the lagoon were measured. The water exchange time of Chiku Lagoon ranges from 1·0 d (June 1997) to 8·5 d (January 1997) with an annual mean of 5·0 d. The residence time of nutrients varies with water exchange time, and is about 2–5 d longer than the water exchange time. Terrestrial inputs and lagoon distributions of nutrients varied in time and space based on the time scale of sampling. Thus, carbon and nutrient budgets were prepared for each sampling period and then combined to form annual budgets, which differed significantly from those modelled from annual means of various parameters. The annual removal of terrestrial nutrient inputs to the lagoon system is 69·4, 47·0, 27·7 and 42·0%, respectively, for DIN, DON, DIP and DOP. Consequently, the nonconservative flux of dissolved inorganic phosphorus (ΔDIP) from the lagoon is around −0·1 mole m−2 yr−1, that is equivalent to an internal organic carbon sink of 11 mol C m−2 yr−1. This organic carbon budget indicates that the lagoon is an autotrophic system where photosynthesis exceeds respiration (p-r> 0). This carbon sink is one of largest reported from world''s lagoons, and its large size may result from the abundant nutrients in the lagoon. However, although the Chiku Lagoon is estimated to remove 4·7 mol C m−2 yr−1 carbonate through oyster calcification, it emits an equivalent amount of CO2 into the system. Despite net nitrogen fixation being observed during some periods, denitrification exceeds nitrogen fixation throughout the period of observation [(nfix-denit)=−1·4 mole N m−2 yr−1]. [Copyright &y& Elsevier]

The Quark Archipelago, in the northernmost part of the Baltic Sea, provides valuable reproduction areas for coastal fish such as pike (Esox lucius L.). Here, pike stocks are still in good condition compared to the southern Baltic Sea, where pike stocks have declined. Hence, this area offers a unique opportunity to study the underlying causes of successful pike reproduction and to identify a productive pike reproduction habitat. This study suggests that the key factor defining suitable reproduction habitats for pike in the Quark Archipelago was the level of shelter. The more sheltered a habitat, in terms of morphology and level of isolation of the site and the site's exposure to wave action and shoreline density, the better the reproduction habitat was for pike. Gloes, which are the most isolated successional stages of coastal lagoons, represented the most sheltered habitat type and showed the highest pike larvae abundance. Additionally, sheltered bays and flads, less isolated successional stages of coastal lagoons compared to gloes, were also used as reproduction habitats by pike but with a lower abundance of larvae compared to the gloes. Gradually increasing salinity and the occurrence of sticklebacks (Gasterosteidae) reflected the morphology of the site. Pike larvae were observed in locations without sticklebacks and with low salinity. Pike larvae were found mostly amongst fallen reed (Phragmites australis) and in areas with moss (Fontinalis sp.) growth, which supports earlier findings. This study provides valuable new knowledge on larval pike habitats and highlights the significance of sheltered bays and gloes in the northern Baltic Sea. The information can be utilised for planning conservation and the restoration of pike reproduction habitats to protect and restore pike populations on both a regional and larger scale. [Display omitted] - The increase of shelter provided by a habitat improves the reproduction habitat for common coastal predatory fish species such as pike. - Shelterness of the habitat was best described by the morphology and level of isolation of the site and the site's exposure to wave action and shoreline density. - Salinity and occurrence of sticklebacks reflect the morphology of the studied habitats, i.e. sheltered bays, pre-flads, flads and gloes. - Pike prefer fallen reed (Phragmites australis) mats and areas with moss (Fontinalis sp.) growth for spawning. [ABSTRACT FROM AUTHOR]

In this article, based on the example of the Toliara lagoon in Madagascar, we identified the major impacts of the two main drivers of the water renewal in a typical channel lagoon: the tide and the swell breaking on the reef. For this purpose, we applied the numerical model Croco which is based on ROMS-AGRIF and uses a realistic and high-resolution configuration. The validation was performed with in situ ADCP data, then, realistic and sensitivity simulations were run to infer tides and waves role in ocean-lagoon exchanges and to estimate water age and water origin. The modelling approach adopted enabled an understanding of the effects of swell and tide on the water renewal. During low wave conditions, tide and waves counteract each other on cross-reef flow: the cross-reef inflow tends to increase with waves breaking on the reef, whereas cross-reef flow tends to decrease or to be outflowing with tidal action. Hence, the lagoon-ocean exchange is reduced and is at a minimum when wave height reaches 0.85 m and the tide has minimum amplitude. During high wave conditions, both tide and waves increase ocean-lagoon exchanges by increasing the cross-reef inflow, whereas during low wave conditions, the cross-reef flow is mainly outward with increase with tidal amplitude and decrease with wave height until the threshold of 0.85 m. • From numerical experiments carried up on Toliara lagoon, we examine: • Tide and waves breaking on the coral reef barrier drive the hydrodynamic circulation on typical channel lagoons. • During wavy events, the main part of the water entering the lagoon is cross-reef water. • During low-wave events, the main part of the water entering the lagoon is through passage water. • During wavy events, the water age decreases with both tidal range and wave height. •During low swell episodes, the water age decreases with tidal range but increases with wave height. [ABSTRACT FROM AUTHOR]

Coastal marsh lagoons are of high ecological relevance playing a key role in the carbon cycle but are threatened to disappear due to global change effects. Restoration practices can counteract this process. This study compares the microbial heterotrophic functioning in three "new" man-made lagoons (created in 2016) to that in three "old" lagoons (two natural plus one created in 2002) from a Mediterranean coastal marsh. The activity of a range of microbial extracellular enzymes, the functional diversity, and the dissolved organic matter (DOM) quality, together with microbial biomass and water physic-chemistry were analysed seasonally in the water column of the six lagoons during 2017. Seasonality was a key driver for the lagoons microbial functioning mainly characterized by lowest microbial activities in winter when DOM was highly aromatic after storm events and an increase in organic matter degradation capabilities from winter to summer probably due to a rise in temperature and DOM input from primary production. Significant differences among lagoons appeared when they were less connected (summer and autumn), and old lagoons showed a greater utilization of proteinaceous and polysaccharidic compounds than new lagoons probably linked to their greater algal biomass (chlorophyll content), which may be supported by their larger phosphorus content. In autumn, there was also a greater use of allochthonous plant material in the old lagoons (higher XYL, and XYL/GLU ratio) probably related to their greater development of riparian vegetation. The functional diversity was the lowest in autumn when the lagoons showed distinct functional fingerprints and the lagoon created in 2002 was grouped with the new ones and distinguished from the natural ones, suggesting that it did not achieve complete restoration. Results indicate that microbial functional parameters related to organic matter use are a relevant and sensitive tool to study lagoon restoration processes, reflecting whole ecosystem nutrient and carbon cycling. [Display omitted] • Microbial functioning in Mediterranean lagoons is mainly driven by season. • Microbial functioning of man-made and natural lagoons differs in summer and autumn. • Natural lagoons show high microbial utilization of nitrogen and carbon sources. • Microbial functional parameters are a sensitive tool to monitor lagoon restoration. [ABSTRACT FROM AUTHOR]

Open anaerobic lagoons are widely used for liquid manure storage and treatment, with excess greenhouse gas (GHG) and odor emissions. In this study, liquid manure was valorized through hybrid nitrogen and phosphorous recovery as value-added products using an airlift reactor. Also, the organic load of liquid manure was reduced before discharging into anaerobic lagoons, which simultaneously mitigated GHG emissions. The results showed that 14.5% of total nitrogen (TN) was recovered as ammonium sulfate, while 38.8% of TN and 79.3% of total phosphorus (TP) were recovered as phosphorus-rich sludge. After the pre-treatment in the reactor, the odor could be controlled effectively due to a 94.2% decrease in total VFAs. In addition, 59.0% of COD was removed, which decreased the theoretical modeled GHG emissions by 51.7% compared to the traditional direct discharging. The application is promising for upgrading anaerobic lagoons of liquid manure. [Display omitted] • Anaerobic lagoon of animal liquid manure could be upgraded through airlift reactors. • 79.3% of TP and 38.8% of TN were recovered as Phosphorus-rich sludge. • 14.5% of TN was recovered as ammonium sulfate. • GHG emissions reduction from the suggested modification was estimated to be 51.7%. • COD and total VFAs were removed by 59.0% and 94.2%, respectively. [ABSTRACT FROM AUTHOR]

Chronic hypoxia and anoxia have strong impacts on coastal ecosystems worldwide. In shallow coastal ecosystems, such situations are essentially driven by high benthic oxygen (O 2) demand resulting from organic matter mineralization in surface sediment and amplified by a low mixing of the water column. However, the benthic O 2 demand may greatly vary according to the O 2 availability, sediment biogeochemical properties, and bioturbation by macrobenthic fauna. Here we examined how the sediment O 2 demand varies in response to seasonal and long-lasting (pluri-decadal) hypoxia in the Berre lagoon, a coastal ecosystem impacted by chronic hypoxia events since 60 years. Oxygen penetration depth, diffusive and total O 2 fluxes were measured in situ using a microelectrode autonomous profiler and benthic chamber deployments at three sites impacted by quite-permanent (PA), seasonal (PI) and occasional (PO) hypoxia in August 2016. They were seasonally repeated at site PI between August 2015 and August 2016. Additional physical and chemical characteristics were also measured in surface sediment. Sediment profile images and characteristics of benthic macrofauna communities enabled to estimate the quality of the benthic ecosystem. The highest benthic O 2 demand was observed after seasonal anoxia in relation to the important accumulation of reduced chemical species in surface sediment. Interestingly, both pluri-decadal hypoxia and normoxia produced relatively high benthic O 2 demand related to a higher accumulation of organic matter and to the presence of reduced chemical species at site dominated by hypoxia, and to the presence of fresher organic matter and active bioturbating macrofaunal communities in normoxic site. The low benthic O 2 demand at site seasonally impacted by hypoxia likely resulted from the degraded state of the macrofaunal community and from the lower accumulation of reduced chemical species. The occurrence of hypoxia and anoxia situations in the Berre lagoon was predicted from the competition between kinetics of benthic O 2 demand and water column reoxygenation events induced by strong wind. The good agreement between the measured and predicted hypoxia/anoxia occurrence clearly indicates that the chronic deoxygenation events in the Berre lagoon, and the resulting degraded ecological state of the benthic ecosystem are driven both by the benthic O 2 demand and by the intensity and duration of the water column stratification. • The benthic oxygen demand (BOD) varies with seasonal and long-lasting deoxygenation events. • BOD is firstly driven by oxygen availability in the water column. • Hypoxia generates highest BOD for the oxidation of accumulated reduced chemical species. • Long-lasting normoxia generates high BOD because of high bioturbation and fresher organic matter. • BOD and water column stratification are responsible of the chronic deoxygenation in the Berre lagoon. [ABSTRACT FROM AUTHOR]

A constant and intense debate in South American archaeology stands on the origin and patterns of food production of ancient populations and the correlation of both aspects with demographic growth and social complexity. Some studies associated population growth with the shift from foraging to agricultural practices in hotspots on the continent. This association has been confronted by a number of studies performed in recent years that reconstructed dietary patterns for several tropical and subtropical areas of eastern South America. However, there is still a lack of information on the diet for Late Holocene populations in the wetlands of the Pampa Biome. In order to access the paleodiet of earthen-mound builders from southern Patos Lagoon (Brazil), this study combined bulk collagen stable carbon and nitrogen isotopes analysis of faunal and human remains with Bayesian Stable Isotope Mixing Models. The paleodiet of 20 human and one dog remains from six sites was reconstructed. The Bayesian mixing model on collagen δ 13C and δ 15N values revealed variable subsistence strategies with high consumption of marine/estuarine protein for some individuals. Other individuals' diets relied on terrestrial/freshwater resources as protein sources. In southeastern South America, such patterns reinforce the resource-rich aquatic environment as a facilitator for the endurance of mixed economies. In addition, our results suggest that the Patos Lagoon surroundings was a "hub of interactivity" characterised by a remarkable intra-site dietary variability. • Diet of Late Holocene mound builders in southern Brazil investigated. • Stable isotopes and Bayesian Mixing Models used for the first time in the region. • Aquatic resources played a major role as sources of dietary proteins and calories. • Mixed economies, not agriculture, fuelled population growth in the region. [ABSTRACT FROM AUTHOR]

The present paper is specifically focused on enclosed or semi-enclosed basins where the wind is the dominant driver of water surface tilting, leading to the so-called wind tide contributing to water levels rise. Wind-induced free surface tilting is studied using the 1-D steady form of the depth-averaged shallow water (Saint-Venant) momentum equation which reflects the depth-averaged local balance between surface slope and wind stress. Two contrasted field sites, the Berre and Vaccarès lagoons, have been monitored providing water level data along a reference axis. This study highlighted the occurrence of wind tides at the two field sites. The bimodal wind exposure ensured the robustness of the observations, with non-linear but symmetric behaviors patterns observed in winds from opposite directions. It is observed that the higher the wind speed, the steeper the slope of the free surface in accordance with the well known basic trend. In addition, a significant effect of depth is observed, with greater surface tilting in the shallower lagoon. The data analysis confirmed the robustness of such a simple approach in the present context. Using the additional assumption of constant, i.e. wind-independent, drag coefficients (C D) allowed a good match with the observations for moderate wind speeds for both sites. However, the depth effect required the C D to be increased in the shallower basin. Classical empirical wind-dependent C D parameterizations provide better wind-tide predictions than the constant- C D approach in very strong wind conditions but totally failed in predicting surface tilting in the shallower site, suggesting that physical parameters other than wind speed should be taken into account for the C D parameterization in very shallow lagoons. • A comparative experimental study of wind-tides in two coastal shallow lagoons. • Wind effects are well predicted using 1-D steady depth-averaged momentum balance theoretical estimation. • Constant surface drag coefficients show a better performance than wind-dependent formulations. • Depth-effect affects surface processes, affecting the drag and the wind-tide amplitude. [ABSTRACT FROM AUTHOR]

Characterizing energy flow and trophic linkages is fundamental to understanding the functioning and resilience of Arctic ecosystems under increasing pressure from climate change and anthropogenic exploitation. We used carbon and nitrogen stable isotopes to examine trophic dynamics and the relative contribution of terrestrial organic matter, water column phytoplankton, and phytobenthos (benthic micro- and macro-autotrophs as well as sea ice algae) to the food webs supporting 45 macroconsumers in three Arctic coastal lagoon ecosystems (Krusenstern, Sisualik, Akulaaq) and the adjacent Kotzebue Sound with varying degrees of connectivity in Cape Krusenstern National Monument, Alaska. A two-source (water column particulate organic matter and benthic sediment organic matter), two-isotope trophic dynamics model informed by a Bayesian isotope mixing model revealed that the Lagoon-Kotzebue Sound coastal ecosystem supported consumers along a trophic position continuum from primary consumers, including amphipods, copepods, and clams to trophic level five predators, such as seastars, piscivorous fishes, seals, and seabirds. The relative contribution of the three primary producer end members, terrestrial organic matter (41 ± 21%), phytoplankton (25 ± 21%), and phytobenthos (34 ± 23%) varied as a function of: 1) consumer foraging ecology and 2) consumer location. Suspension feeders received most of their carbon from food webs based on phytoplankton (49 ± 11%) and terrestrial organic matter (23 ± 5%), whereas herbivores and detritivores received the majority of their carbon from phytobenthos-based food webs, 58 ± 10% and 60 ± 8%, respectively. Omnivores and predators showed more even distributions of resource reliance and greater overall variance among species. Within the invertebrates, the importance of terrestrial organic matter decreased and phytobenthos increased with increasing trophic position. The importance of terrestrial organic matter contribution increased with lagoon proximity to major rivers inputs and isolation from Kotzebue Sound. Several taxa with cultural and subsistence food importance to local communities showed significant reliance (30–90% of baseline carbon) on food chains linked to fresh terrestrial organic matter. Our study indicates that terrestrial-marine linkages are important to the function of Arctic coastal lagoon ecosystems and artisanal fisheries. These linkages are likely to strengthen in the future with regional changes in erosion and runoff associated with climate change and anthropogenic disturbance. [Display omitted] • Strong terrestrial-marine coupling is important to Arctic coastal lagoon food webs. • Coastal Alaskan lagoons were characterized by long food chains. • Importance of terrestrial organic matter varied by foraging ecology and location. • Subsistence target fishes relied on terrestrial organic matter-based food webs. [ABSTRACT FROM AUTHOR]

Mercury in the aquatic environment can lead to exposure of the human population and is a known toxic metal due to its capacity for accumulation in organs. We aimed to evaluate the mercury level in the blood and urine of fishermen and correlate it with the level of oxidative stress in blood cells. We show in this case-control study that the fishermen of the exposed group (case) of Mundaú Lagoon (Maceió - Alagoas, Brazil) have higher concentrations of total mercury in the blood (0.73–48.38 μg L−1) and urine (0.430–10.2 μg L−1) than the total mercury concentrations in blood (0.29–17.30 μg L−1) and urine (0.210–2.65 μg L−1) of the control group. In the blood cells of fishermen, we observed that the lymphomononuclear cells produced high levels of reactive oxygen species (61.7%), and the erythrocytes presented increased lipid peroxidation (151%) and protein oxidation (41.0%) and a decrease in total thiol (36.5%), GSH and the REDOX state (16.5%). The activity of antioxidant system enzymes (SOD, GPx, and GST) was also reduced in the exposed group by 26.9%, 28.3%, and 19.0%, respectively. Furthermore, hemoglobin oxygen uptake was decreased in the exposed group (40.0%), and the membrane of cells presented increased osmotic fragility (154%) compared to those in the control group. These results suggest that mercury in the blood of fishermen can be responsible for causing impairments in the oxidative status of blood cells and is probably the cause of the reduction in oxygen uptake capacity and damage to the membranes of erythrocytes. • Fishermen's blood that living around Mundaú lagoon (Brazil) has a higher Hg level. • Fishermen's lymphomononuclear cells produced 61.7% more reactive oxygen species. • In erythrocytes of fishermen, mercury induces oxidative damage in biomolecules. • The enzymatic antioxidant system was no efficient in erythrocytes of fishermen. • Fishermen's oxygen uptake and membrane integrity of erythrocytes were compromised. [ABSTRACT FROM AUTHOR]

Element-to-calcium ratios of bivalve shells are potentially useful proxies for environmental change, provided the relationship between the environmental variable and element ratio are calibrated using modern specimens. In this study we investigate the utility of trace elemental ratios in the estuarine micromollusc Arthritica helmsi as (palaeo)environmental proxies. Sr/Ca, Mg/Ca and Ba/Ca ratios were measured in waters (n = 137) and live bivalves (n = 125) were collected along a salinity gradient from fresh to hypersaline in the Coorong Lagoon and Lake Alexandrina, at the terminus of the Murray River, South Australia. Water Mg, Sr and Ca exhibited linear relationships with salinity, while Ba showed no relationship. Mg/Ca and Sr/Ca in water both showed positive logarithmic responses to increasing salinity, while the response of Ba/Ca was best explained by a negative power function. The Sr concentration and Sr/Ca of water collected between 2016 and 2018 were elevated compared to a previous study conducted between 2007 and 2008, possibly due to a higher river flow regime in the more recent period. The range of Sr/Ca, Mg/Ca and Ba/Ca measured in A. helmsi were in agreement with previous studies, as were the range of partition coefficients. However, the incorporation of Sr/Ca, Mg/Ca and Ba/Ca did not correlate with water elemental ratios, temperature, salinity or pH and are therefore likely to be more heavily influenced by biological processes. As a consequence, while the elemental composition of other carbonate fossils within the Coorong system may hold potential to reconstruct past climate and environmental change, the trace element geochemistry of A. helmsi aragonite shells, and possibly other similar micro-bivalve molluscs, should be treated with caution as a palaeoenvironmental tracer. • Mg/Ca in the Coorong Lagoon waters were stable in comparison to previous studies. • Sr/Ca and Ba/Ca in the Coorong Lagoon waters were influenced by changes in hydrological regime. • Elemental incorporation into Arthritica helmsi was not controlled by temperature, salinity or water element ratios. • Element ratios and element partitioning in Arthritica helmsi were in good agreement with previous studies. [ABSTRACT FROM AUTHOR]

The genus Caulerpa has attracted much attention because many of its species were introduced into non-native regions and became notoriously invasive. This is the case of Caulerpa prolifera that has been rapidly expanding in Ria Formosa lagoon, taking over the deeper unvegetated soft bottoms and competing with seagrass meadows in the shallower areas. Here we address how C. prolifera invasion may affect the support of biodiversity, and specifically, the provision of habitat and nursery for commercial species by the native habitats of this coastal lagoon. Even though no significant differences in total species richness, diversity and evenness were found between C. prolifera and the native unvegetated habitat, the dissimilarity between these two habitats was highest, mostly driven by the extreme reduction of the gastropod Bittium reticulatum and of the tanaid Apseudopsis formosus. This may implicate changes in the trophic interactions of the ecosystem, for example decreasing the tanaid food source for seahorses, which are presently endangered in the lagoon. On the other hand, the fauna species richness, diversity and evenness were significantly higher in the native seagrass habitat than in C. prolifera. Juveniles of valuable flat and sparid fish were only observed in unvegetated sediments and seagrass meadows, respectively. The aggressive spread of C. prolifera in Ria Formosa may alter the structure of native faunal communities, with likely negative implications on fisheries. Nevertheless, the global biodiversity of the lagoon will not be likely drastically affected unless the seaweed takes over the seagrass meadows. • Caulerpa prolifera takeover in Ria Formosa will alter the structure of native faunal communities. • Nursery services for valuable flat and sparid fishes are negatively affected by Caulerpa prolifera spread. • The species richness and diversity is significantly reduced compared to seagrass meadows, but not to unvegetated habitats. • Caulerpa prolifera spread in Ria Formosa is expected to have economic implications. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) are a potential solution for wastewater treatment due to their capacity to support native species and provide tertiary wastewater treatment. However, CWs can expose wildlife communities to excess nutrients and harmful contaminants, affecting their development, morphology, and behavior. To examine how wastewater CWs may affect wildlife, we raised Southern leopard frogs, Lithobates sphenocephalus, in wastewater from conventional secondary lagoon and tertiary CW treatments for comparison with pondwater along with the presence and absence of a common plant invader to these systems – common duckweed (Lemna minor) - and monitored their juvenile development for potential carryover effects into the terrestrial environment. The tertiary CW treatment did not change demographic or morphological outcomes relative to conventional wastewater treatment in our study. Individuals emerging from both wastewater treatments demonstrated lower terrestrial survival rates than those emerging from pondwater throughout the experiment though experiment-wide survival rates were equivalent among treatments. Individuals from wastewater treatments transformed at larger sizes relative to those in pondwater, but this advantage was minimized in the terrestrial environment. Individuals that developed with duckweed had consistent but marginally better performance in both environments. Our results suggest a potential trade-off between short-term benefits of development in treated effluent and long-term consequences on overall fitness. Overall, we demonstrate that CWs for the purpose of wastewater treatment may not be suitable replicates for wildlife habitat and could have consequences for local population dynamics. • Frogs that developed in wastewater were bigger than those from pondwater. • Development in wastewater yielded slower growth and lower survival. • Frogs developed similarly in secondary and tertiary treated wastewater. • Constructed wetlands for wastewater treatment may negatively affect wildlife. [ABSTRACT FROM AUTHOR]

After visual analysis of more than 3000 satellite images for 2013–2020, it was found that the presence of recurring (stationary or stable) polynyas in coastal lagoons in the Northern Hemisphere of the boreal and polar climate zones of the Atlantic, Pacific and Arctic Oceans was quite common. At least 115 out of 246 lagoon-type coastal objects demonstrated this (47%). Polynyas were primitively classified into two types: the flowing polynya (due to a river inflow in a lagoon), and the inlet polynya (with three subtypes: the inward, outward and «window» ones) attached to the lagoon inlet. The geographical distribution of the lagoons with polynyas was discussed. Some comments on different mechanisms (thermal and mechanical) that guided the polynyas' appearance in the lagoons were presented. It was noted that statistical distributions of the number of the polynyas by polynya areas or relative size of polynya areas (ration of polynya areas to lagoon areas) could be expressed by lognormal distribution function. • Recurring polynyas in coastal lagoons were quite common, at least 115 out of 246 lagoons demonstrate this (47% of lagoons). • Typology: the inlet polynya with three subtypes – the inward, outward, «window» polynyas and the flowing polynya. • Zoning by the presence of the recurring polynyas were made for coasts of the Atlantic, Pacific and Arctic Oceans. • Recurring polynyas are the manifestations of thermal or mechanical mechanisms guided the polynya origin and support. • Statistical distributions of the normalized areas and relative sizes of the polynyas are expressed by lognormal function. [ABSTRACT FROM AUTHOR]

Spatial variability of ciliates in relation to environmental variables and abundance of heterotrophic prokaryotes, picoeukaryotes, nanoeukaryotes, microphytoplankton and mesozooplankton were studied in the Gulf of Gabes- Boughrara lagoon system in the surface layer and at the water-sediment interface between 9 and April 15, 2017. Results revealed a striking difference between the two ecosystems, with higher temperature and salinity and high availability of nitrite and total nitrogen concentrations in the Boughrara lagoon, probably generated by limited exchanges of water with the Gulf of Gabes associated with disturbed areas in the lagoon. Ciliates abundance was slightly higher in the Gulf of Gabes (16–19 × 102 cells l−1) than in the Boughrara lagoon (13–16 × 102 cells l−1), but the species richness was significantly higher in the Boughrara lagoon (40 taxa in the surface layer and 35 taxa at the water-sediment interface) than in the Gulf of Gabes (35 taxa in the surface layer and 33 taxa at the water-sediment interface). The ciliate community was characterized by the predominance of Spirotrichea. Tintinnids were more abundant than naked ciliates in both sampled ecosystems, except in a few stations. Some tintinnid species, such as Tintinnopsis radix , T. nana and T. parvula , showed high abundance, indicating their tolerance to environmental pollution. The dominant species T. beroidea , T. nana and Strombidium compressum showed significant relationships with nutrient concentrations, illustrating their affinity for highly eutrophic sites. Regression and correlation analyses suggest food dependence of Spirotrichea and tintinnids up on picoeukaryotes, whereas naked ciliates appeared more controlled by the availability of nanoeukaryotes and microphytoplankton. Metazooplankton abundance showed no significant relationships with ciliate abundance. • Ciliate community composition was dominated by tintinnids. Naked ciliates were dominated by Spirotrichs. • Temperature showed negative effect on the structure of total ciliates and Spirotrichea. • Ciliate diversity, in the Boughrara lagoon, was more important than in the Gulf of Gabes. [ABSTRACT FROM AUTHOR]

Benthic foraminifera are deemed sensitive indicators of environmental conditions. Triggers and magnitudes of faunal response to environmental changes are yet poorly constrained. Benthic foraminiferal faunas were monitored annually at Ria Formosa (Algarve, Portugal) coastal lagoon since 2013. Distinct environmental changes were recognised during the monitoring period. The relocation of a tidal inlet in winter 2015 effected faster flushing, higher tidal levels, and stronger currents in the Esteiro do Ancão tidal channel. The epibenthic foraminiferal species Asterigerinata mamilla increased in abundance and the population densities of the whole fauna were double as high as before inlet relocation. Enhanced sediment redeposition was recorded and extensive polychaete colonies successively replaced firmground patches with oysters. The standing stock of the foraminiferal fauna declined in the next year due to food impoverishment, while the high hydraulic energy levels and high percentages of Asterigerinata mamilla maintained. Benthic foraminifera responded much faster to environmental perturbations than macroorganisms identifying them as powerful proxies in environmental studies. [Display omitted] • Foraminifera responded faster to environmental perturbations than macroorganisms. • Population densities doubled and Asterigerinata mamilla bloomed under stronger flow. • Excess of threshold values and changes to new ecosystems induce acme occurrences. [ABSTRACT FROM AUTHOR]

Modelled and observed tendencies of temperature and salinity are investigated to assess the factors governing the heat and salt in the Pulicat lagoon, a hypersaline (>3.5%) lagoon along the south east coast of India. The salinity of the lagoon is extremely fluctuating, shifting regimes from fresh to hypersaline on seasonal scales. Examination of the spatio-temporal variability of the salinity of the lagoon shows certain regions of the lagoon remain hypersaline during most of the year. Hydrology and vertical solar heat fluxes constitute the major governing factors of the salt and heat of the lagoon respectively, while advection by hydrodynamics is important in specific regions during particular time of the year. Extremely high salinities higher than previously reported values, exceeding those during severe drought conditions were observed during this study period. A first account of meromixis with high heliothermic subsurface temperature and salinity during winter months November to February of different years in an embedded region of the lagoon is reported. • Tendency equations for temperature and salinity are examined. • Extreme salinities exceeding earlier records are reported for the first time. • Middle-inlet of the lagoon observed to be meromictic and heliothermic for the first time. • Impact of hydrodynamics on salinity and temperature is limited to specific seasons and regions. [ABSTRACT FROM AUTHOR]

To predict the responses of organisms to changes in intensity and frequency of heatwaves, it is essential to gain a thorough understanding of how organisms respond to temperature exposure. Species-specific curves are more informative, yet more difficult to ascertain, than the generic heatwave definition (five days or more at a temperature above the 90% percentile) when addressing mortality risk and should be included when predicting thermal risks. The thermal tolerance of organisms is dictated by a combination of exposure intensity and duration: the aim of this study was to build a 'tolerance landscape' model, based on exposure thresholds to a potentially stressful temperature range, for the commercially important clam Ruditapes philippinarum using ten years of summer temperature time series in four lagoons in the Northern Adriatic, where this species is being commercially farmed. The model is based on a log-linear relationship between LT 50 and exposure time. The two model parameters, i.e. the lethal temperature at 1 min exposure (CT max), and the temperature sensitivity parameter (z) were estimated on the basis of a systematic literature search. Best-fitting values, i.e. CT max = 54.5 (±2.3) and z = - 5.72 °C (±0.66) are within the ranges found for other bivalves. Results show that the mortality threshold was exceeded for most lagoons in summertime in 2015, 2017 and 2018 suggesting that the risk of exceeding the mortality threshold is increasing, due to an increase in frequency and duration of extreme temperature events. Comparisons with the generic 'marine heatwave' definition showed that, while in some occasions 'heatwaves' occurred that were not risky for R. philippinarum , in one case the model identified a time period of mortality risk that would not have been classified under the generic 'heatwave' definition. These mismatches suggest that tolerance curves can be a good addition to productivity and site selection models, incorporating a metric of species-specific risk that can be used to predict the consequences of climate change on fishery and aquaculture, and can find their place in conservation and restoration toolkits for forecasting changes in habitat suitability under future climate scenarios. [Display omitted] • Literature data were used to build a tolerance landscape model for R. philippinarum. • 50% mortality threshold was exceeded for most lagoons in 2015, 2017 and 2018. • Mortality risk was not always adequately described by the heatwave concept. [ABSTRACT FROM AUTHOR]

Coastal lagoons are resilient and productive ecosystems that support high biological and habitat diversity, but are increasingly affected by several threats due to human exploitation. Many resident species of these environments show a restricted geographical range and a strict association with specific habitats, thus they could represent ecological indicators of these ecosystems. Data on the genetic variability distribution in populations of these species are crucial to identify the presence of different evolutionary units across their geographical distribution ranges and to plan actions for their management and conservation. In this context, the assessment of the genetic variability and structure of Italian specimens of the Adriatic dwarf goby Knipowitschia panizzae, a brackish species endemic in the Adriatic Sea, and included among the species of Community interest in Annex II of Habitats Directive, was carried out. To this purpose, goby samples were collected both from Italian sites where the species is native (Adriatic) and non-native (Tyrrhenian), probably introduced due to the practice of stocking lakes and coastal lagoons with juvenile of euryhaline species to sustain local fisheries. Results show the presence of high values of haplotype diversity, and no shared haplotypes between fish from sites where the species is native or introduced. Moreover, in Tyrrhenian Italian lagoons we identified an allochthonous species of Knipowitschia , previously undetected in Italy: the Corfu dwarf goby K. goerneri. This species was originally described as endemic to the Korission Lagoon catchment on Corfu Island, but recently found also in Butrinti lagoon in Albania. The presence of this species, that almost totally replaced Adriatic dwarf goby in the Tyrrhenian lagoons under study, can be ascribed to the stockings of wild fry of commercially important species originating from Balkan countries. • Coastal lagoons support high biodiversity and habitats but are increasingly threatened. • Genetic data of a species are crucial for conservation actions. • Molecular tools represent an easy resource to support classical taxonomy. • Non-native species can be translocated by stocking coastal lagoons. • Fish introductions might compromise the survival and integrity of local populations. [ABSTRACT FROM AUTHOR]

Lagoons and coastal marine zones are very productive and useful ecosystems, but they are threatened by the effects of global change and anthropogenic pressures. These effects have a negative impact on the zooplankton, weakening its function of phytoplankton consumer, leading to uncontrolled proliferation of microalgae in case of eutrophication. In this study we test the hypothesis that tidal exchanges with the sea can counteract these deleterious effect, by renewing the zooplankton community and by enhancing its top-down control of phytoplankton through selective retention of zooplankton grazers. Our study focused on the southern region of the Gulf of Gabes and the Boughrara lagoon which presents the highest tidal range in the Mediterranean. During two field campaigns (October 2016 and April 2017) we have analyzed zooplankton descriptive (taxonomic composition, abundance; biomass) and functional (ingestion rate, grazing pressure) variables and environmental variables during time series at a fixed station during ebb-flood sequences and at 8 stations along a sea-lagoon transect and during different tidal amplitude periods. Multivariate analyses of both environmental parameters and zooplankton taxa showed the existence of three distinct zones along the sea-lagoon transect, but also the influence of tidal circulation and water mixing on the renewal of the zooplankton community up to the innermost zones of the lagoon. Time series gave clear patterns for the input/output of marine/lagoon species and show a net import for different taxa and for the total zooplankton abundance and biomass (mean flood/ebb ratio = 2.2 for the total abundance and 2.4 for the biomass), leading to differential retention of zooplankton in the lagoon and to an increase in the potential grazing pressure on phytoplankton (mean flood/ebb ratio = 2.8). We also estimated that the grazing pressure in the lagoon was twice higher during the periods of high tidal amplitudes (at or close to spring tide) compared to periods with low amplitude (neap tides), clearly showing that the retention of zooplankton significantly increases the grazing impact on phytoplankton. These results highlight the importance of the tidal forcing for maintaining the good status of the zooplankton structure and function in strongly anthropized coastal and lagoon ecosystems. • Tidal circulation is a major forcing for coastal and lagoon ecosystems. • Tidal forcing maintains zooplankton diversity and community structure. • Tidal exchanges with the sea drive selective retention of zooplankton. • Zooplankton retention increases grazing impact on phytoplankton. • Tidal circulation may limit anthropization effects. [ABSTRACT FROM AUTHOR]

The Vistula Lagoon is an almost closed basin at the southern coast of the Baltic Sea. Its mild salinity gradient provides a unique environment for the coexistence of freshwater and marine bacteria. This study employs catalysed reporter deposition-fluorescence in situ hybridisation (CARD-FISH) to investigate seasonal dynamics of marine (SAR11 clade I/II) and freshwater (SAR11 clade IIIb (LD12), Limnohabitans clades B, C, D, Burkholderiales (former Betaproteobacteria)) bacterial groups. Samples were collected from below the ice in February, and then monthly from April to October 2011 from three stations with different salinity. The abundance of SAR11 clade I/II strongly positively correlated with salinity, with the highest abundance in autumn at time of inflows of saline waters from the Baltic Sea. Two groups (spring-summer and autumn-winter) were distinguished within this clade, based on a scatter chart between SAR11-I/II abundance and salinity. Salinity explained 69% of the variability of the spring-summer group and 77% of the autumn-winter group. This suggests that the presence of marine SAR11-I/II in the Vistula Lagoon was caused by passive inflow with waters from the open Baltic Sea, and this environment is not suitable for its regular existence. The abundance of the freshwater SAR11 clade IIIb was similar to that of SAR11-I/II. However, it depended on temperature, organic and inorganic phosphorous, and not on salinity, suggesting that SAR11-IIIb found a regular niche in the eutrophic Vistula Lagoon. Burkholderiales positively correlated with temperature, chlorophyll-a, organic and inorganic phosphorous, and heterotrophic nanoflagellates, suggesting that their role in the Vistula Lagoon may be similar to that in lakes. Interestingly, Burkholderiales had the highest relative abundance under ice in February. Finally, the abundance of Limnohabitans clades B, C, D positively depended on temperature, chlorophyll-a and negatively on salinity. This together with positive correlation with Cryptophytes and with heterotrophic nanoflagellates emphasis its importance in this ecosystem. These results show that the conditions in the Vistula Lagoon are rather inappropriate for typical marine bacteria, while freshwater bacteria may find their niches despite slightly elevated salinity. • Marine SAR11-I/II was passively brought to the Lagoon with waters inflowing from the Baltic Sea. • Freshwater SAR11-IIIb and Limnohabitans are active members of the bacterial community in the Vistula Lagoon. • Burkholderiales had the highest relative abundance under ice cover in winter. [ABSTRACT FROM AUTHOR]

We studied the potential of zebra mussel farming for nutrient retention in a eutrophic lake. Duplicate experimental long-line cultivation units were deployed and mussel growth and nutrient retention were quantified after 28 months. Mussels grew well at shallow water depth (<3 m) and our 625 m2 (lake area) experimental units produced 507 and 730 kg dry biomass, respectively, of which 94% were shells. These yields corresponded to an average retention of 92.7 ± 23.1 kg C, 6.1 ± 0.68 kg N, and 0.43 ± 0.04 kg P retention, or 742 kg C, 49 kg N, and 3.5 kg P for a full-size (0.5 ha) mussel farm. We estimate that concentrating the long-lines to a depth of 2.5 m would probably have doubled these yields, based on the differences in mussel growth among depths. We further estimate that a full-size cultivation unit (0.5 ha) thus could compensate for the annual total-P run-off from 23 ha, or the biologically available P from approximately 49 ha of agricultural soils. As traditional measures have proven insufficient, decision-makers need to facilitate novel approaches to mitigate the negative effects of cultural eutrophication. We envision that zebra mussel farming, within their invaded range, provides a promising approach to invert nutrient losses in lakes and coastal lagoons. • Zebra mussel cultivation units produced between 507 and 730 kg dry biomass, of which 94% shells. • 0.5 ha of mussel cultivation can compensate for the bioavailable P from 49 ha of agricultural soils. • Zebra mussel farming is a promising approach to invert nutrient losses to lakes and coastal lagoons. • Zebra mussel can only be applied in the species' invaded range. Zebra mussel cultivation efficiently traps highly bioavailable nutrients, thereby inverting the flux of nutrient from land to water, alleviating cultural eutrophication, and improving water quality. [ABSTRACT FROM AUTHOR]

Many studies about the susceptibility of coastal systems to flood hazard have been carried out using similar methodological approaches, based on the spatial integration of structural and dynamical variables. However, although the general framework fits well to most exposed coastal sectors, few examples can be found in the literature regarding the proposal of dynamical descriptors (variables of process) particularly relevant to the analysis of the physical vulnerability of sheltered coastal systems, such as lagoons. The aim of this study was to propose a methodology to assess the physical vulnerability to sea-level rise due to climate change which was tested in the Conceição Lagoon, located in Santa Catarina (Brazil), based on dynamic descriptors obtained from numerical modeling. After implementing a numerical model calibrated to satisfactorily reproduce the hydrodynamic characteristics of the studied system, we simulated different sea-level rise scenarios proposed by the Intergovernmental Panel on Climate Change (IPCC), using optimistic and pessimistic scenarios for the years 2050 and 2100. Results were classified following the often-adopted scheme of very low to very high vulnerability. The maximum variations in the lagoon level calculated by the model showed the importance of winds and tides (both astronomical and meteorological) as the main triggering processes of level oscillation. The final physical vulnerability spatial distribution, obtained by the integration of maximum lagoon level variations associated with future projections, allowed the recognition of the sectors within the lagoon system which are more prone to suffering impacts. Most of the system was considered to have an intermediate vulnerability to sea-level rise. However, sectors with high vulnerability were also identified, mostly located at the northern and southern shores of the lagoon (due to wind influence), as well as along its inlet margins (due to ocean dynamics). The proposed framework based on the variations of the water level can be widely adopted as a descriptor that synthesizes the main dynamic processes responsible for the physical vulnerability of sheltered systems, fitting to lagoons and bays with different physiographic characteristics. The determination of the spatial distribution of areas with different degrees of susceptibility can be a valuable tool for coastal planning and management actions to be performed in sheltered systems, which has been overlooked comparing to those applied in open coasts. • Few studies have proposed physical vulnerability dynamical descriptors of flood hazard in sheltered areas. • Maximum water levels in a subtropical lagoon were simulated using numerical modeling and sea-level scenarios. • Very high physical vulnerability to sea-level rise was found in 58.88% of system's margins. • Worst case scenario anticipated for 2100 a maximum level increment of 2.23 m in some sectors. • Water level variation efficiently summarizes dynamic processes responsible for physical vulnerability in sheltered systems. [ABSTRACT FROM AUTHOR]

Anguillicola crassus , a haematophagous nematode infecting the eel swim bladder, was introduced into Europe from Asia in the early 1980s with imported Anguilla japonica. It spread rapidly after establishment in the native European eel Anguilla anguilla. A long-term dataset shows the dynamics of A. crassus in eels of the Comacchio Lagoon from 1997 to 2019, and reveals the factors that influence its prevalence. A sample of 339 eels showed 19 parasitized by adult A. crassus , with one to five parasites per infected host and a mean abundance of 0.09 ± 0.45. Prevalence ranged from 2.14% (minimum value reached in 2005/06) to 11.9% (maximum reached in 1997). No significant temporal trend in the occurrence of A. crassus was detected over the period of the investigation, which was characterized by low levels of infection compared to that in eel populations from other coastal lagoons or estuaries. No influence of A. crassus on condition factor, hepatosomatic and gonadosomatic index and swim bladder integrity (evaluated through the Swim bladder Degenerative Index) was found, suggesting a minimal impact of the parasite on the eel population health. Anguillicola crassus , although established in Comacchio Lagoon, has not become invasive. The possible reasons for this, among which high salinity, will be discussed. Management of the lagoon for the past 30 years has also contributed to parasite containment through avoidance of restocking the eel population from external sources. • Infection rate of A. anguilla by the nematode A. crassus was low over 20 years. • The parasite had a very low impact on the eel population health. • High salinity contributed to limit parasite occurrence. • Conditions in and management of lagoons may strongly influence A. crassus. [ABSTRACT FROM AUTHOR]

The pollution of beach litter was seasonally evaluated in a selected beach in the West Mediterranean Region of Turkey between December 2019 and September 2020. Beach litter survey was carried out seasonally according to 'Guidance on Monitoring of Marine Litter in European Seas' published by European Marine Strategy Framework Directive Technical Subgroup on Marine Litter. During the study, a total of 2.324 items and 105.44 kg were collected. The average litter density was 581.0 ± 60.04 items/m2 and 26.36 ± 0.85 g/m2. The results indicated that the most common type of litter were plastic/polystyrene (35%), unidentifiable (18%) followed by cloth/textile (16%). Litter density showed significant seasonal differences with the highest in summer (P < 0.05). Homa beach was classified as "dirty" according to Clean Coast Index. It was observed that the litter in the region averagely consisted of mixed packaging litter (24.25%), fisheries related litter (19%) and unclassified litter (15.25%) items. Our results show that the coast of Homa Lagoon exposed to a significant amount of marine litter pollution originated from land-based sources. This study provides further evidence that there is a significant litter pollution in the West Mediterranean Sea of Turkey and that the main component are plastics, which pose a great treat to the Mediterranean Sea environments. • The main source of marine litter in the Mediterranean is households. • A large proportion of marine litter is plastics. • Marine litter pollution dominantly originated from land-based sources. • Foreign origin litter originated from predominantly neighbouring countries. [ABSTRACT FROM AUTHOR]

Invasive ecosystem engineers change habitat attributes and species abundance, affecting the structure of invaded communities. In the Mar Chiquita coastal lagoon (37° 40′S, 57° 23°W), the invasive reef-building polychaete Ficopomatus enigmaticus (Fauvel, 1823) generates a heterogeneous environment with habitats of variable complexity: the reefs themselves (high complexity), the sediment surrounding the reefs (low complexity), and the substrate from the areas without reefs (intermediate complexity). Our objective was to compare the macrofaunal assemblages along the whole complexity gradient. We hypothesized that individuals' abundance, diversity, species richness, and evenness of the macrofaunal assemblages increase with habitat complexity, since more complex habitats may represent greater availability of suitable spaces. The composition of the species assemblage was compared through monthly field samplings in each of the three habitats. Results showed that individuals' abundance increased with habitat complexity. In addition, amphipods were the most abundant group in the reefs, while ostracods were the most abundant group in the sediment surrounding the reefs and that from reef-free areas. However, community parameters were occasionally similar between the reefs and the sediment from reef-free areas, depending on the month considered. Our study suggests that the invasion of F. enigmaticus changed the macrofaunal assemblages and the individuals' abundances by providing a high complexity substrate, but also, and less predictably, by increasing habitat heterogeneity, highlighting the importance of including both dimensions of habitat structure in the study of invasions by ecosystem engineers. • Macrofauna abundance was higher in F. enigmaticus reefs, intermediate in reef-free sediment, and lower in the reef-sediment. • Community parameters were similar between reefs and reef-free sediment. • Overall, soft-bottoms' contribution to the community could be equivalent to F. enigmaticus reefs. [ABSTRACT FROM AUTHOR]

Aquatic metabolism is an important descriptor of ecosystem functioning. The metabolism of ponds and confined coastal lagoons has been poorly studied in comparison to other aquatic systems, in which the metabolic dynamics are better understood. In this study, we described the ecosystem metabolism of two confined Mediterranean coastal lagoons located in La Pletera salt marsh (NE Iberian Peninsula), which is dominated by flooding-confinement patterns. We estimated the metabolic rates by applying Bayesian models to three years of high-frequency open water oxygen data. Our aim was to test if nutrients and other environmental variables (the temperature, conductivity, light and water level) that registered as important drivers of metabolism in the literature were the primary drivers of metabolic variation in confined coastal water bodies. We observed clear seasonal patterns in the metabolic rates, with extremely high oxygen variability during the summer season ranging from supersaturation (saturations > 200% were recorded) to anoxia (<5%). Despite the high rates of production registered during the summer, periods of anoxia could prevail for several days during that season. Thus, although the aerobic production and respiration were quite balanced in the lagoons during the study period, these lagoons are probably more heterotrophic since their anaerobic respiration has not been estimated. Because the studied lagoons are rich in nutrients, we expected a low response in the metabolic rates to nutrient increases, since the physiological response of primary producers to nutrient loading is usually low in nutrient-saturated ecosystems; our results supported this hypothesis. The temperature was the primary driver, highlighting the importance of seasonality in these highly productive ecosystems. Our results also showed an uncoupling between the metabolic rates, which were higher in the summer, and the standardized ones, after removing the temperature and irradiance effects, which were higher in the winter and negatively related to the conductivity. This finding suggests that potential productivity (standardized rates) is more sensitive to winter inputs and, in contrast, the actual productivity is more related to summer concentration processes due to confinement. Image 1 • Metabolic rates in confined lagoons vary seasonally, with high values in summer. • Summer periods are characterized by extended anoxia. • Nutrient concentrations do not drive metabolism in these ecosystems. • Standardized rates show the potential productivity of these lagoons during winter. [ABSTRACT FROM AUTHOR]

This study reports on the spatiotemporal distributions of zooplankton assemblages during two harmful algal blooms (ΗΑΒs) and a dystrophic crisis in Papas lagoon (W Greece, E Mediterranean), a water body with a long history of eutrophication phenomena. The main focus is placed on the impact of toxic microalgae on the metazooplankton community structure under contrasting environmental conditions including an anoxic event. Towards this aim, we recorded environmental parameters and sampled different size components of plankton communities (microalgae, microzooplankton and mesozooplankton) over the course of a year, in order to assess the metazooplankton assemblages (using nMDS, PERMANOVA and CCA) within a more comprehensive framework, considering lower trophic levels. HABs had a detrimental impact on all key holoplankton and meroplankton taxa regardless of environmental conditions, while their co-occurrence with anoxia resulted in the collapse of zooplankton populations. Recovery of zooplankton abundances after the compounded effects of HABs and anoxia was significantly slower in relation to the sole impact of HABs. Concerning holoplankton, dominance of egg-spawning calanoid copepods (Acartia clausi, Paracartia latisetosa) prior to the compounded extreme events shifted to smaller egg-carrying harpacticoids (Euterpina acutifrons) and cyclopoids (Oithona nana) in the recovered assemblages while in meroplankton, bivalvia larvae were largely replaced by cirripedia nauplii. These results suggested that the cumulative effects of HABs and dystrophic crises may significantly alter the taxonomic composition and size-structure of metazooplankton communities with possible harmful consequences for ecosystem functioning and fish and shellfish recruitment. • The effect of HABs on zooplankton populations was detrimental regardless of environmental conditions. • HABs and anoxia resulted in the collapse of zooplankton abundances. • Compounded effects of HABs and anoxia altered species composition and size structure of zooplankton assemblages. • Zooplankton recovery was faster after the sole impact of HABs in comparison to their cumulative effects with anoxia. [ABSTRACT FROM AUTHOR]

Sludge is nutrient and mineral rich residue of anaerobic treatment that is often utilized as a fertilizer. Sludge management is crucial to maintain the function of anaerobic treatment lagoons and ensure efficient nutrient utilization. Intensive livestock production has resulted in accumulation of sludge residue in regions where nutrients are in surplus. This situation adversely impacts the sustainability of livestock production. Alternative uses of sludge needs to be developed and adopted to reduce the negative impacts associated with the nutrients accumulation on farms and nearby crop fields. A thorough understanding of sludge composition is necessary to identify appropriate end use. This review explores swine lagoon sludge (SLS) in relation to its composition, sampling techniques, management approaches, fertilizer value, challenges and opportunities for further development. • A review of swine lagoon sludge sampling, characterization and use is presented. • Lagoon sludge sampling techniques are not standardized. • Sludge composition in swine lagoons varies considerably. • Elevated P, Cu, Zn contents in sludge limits its application as a fertilizer. • Composting and drying are promising sludge processing techniques. [ABSTRACT FROM AUTHOR]

Blooms of jellyfishes are perceived to have increased during the last decades causing interference with human activities of both recreational and professional type. Those blooms seem to hold correlation with human impacts and environmental changes such as overfishing, the increase of temperature, eutrophication or habitat modification. In this study we perform the first simultaneous analysis of population dynamics from three scyphozoan jellyfishes, Aurelia sp. (Linnaeus, 1758), Cotylorhiza tuberculata (Macri, 1778) and Rhizostoma pulmo (Macri, 1778). The effect of temperature, salinity, ichthyoplankton, nutrients and chlorophyll a concentration have been studied. These three species are present in the Mar Menor coastal lagoon where they show a spatial and temporal segregation of their populations and life cycles that allows them to reduce interspecific competition. Temperature and its seasonal cycle have been determined to be a key factor regulating the populations, triggering the strobilation process either by an increase in temperature (C. tuberculata) or by a decrease in it (Aurelia sp.). Such segregation has a decisive effect on the ecosystem, since it allows a continuous temporal succession of top-down control on the lagoon trophic network. • Life cycle and populations of the three jellyfish are spatio-temporally segregated. • Reproductive strategies differ in timing and aggregation behaviour. • Temperature seasonal cycle is the key factor regulating growth and population dynamics. • Sudden changes in temperature were the main triggering factor for the strobilation. • Segregatopm allows a continuous temporal succession of top-down control on the lagoon trophic network. [ABSTRACT FROM AUTHOR]

Dark carbon fixation is a combination of processes performed by microorganisms to fix inorganic carbon driven the energy generated by chemical reactions. Our study quantified microbial primary and secondary production rates to evaluate the relative importance of dark carbon fixation in relation to photosynthetic rates and heterotrophic bacterial production and their contribution to the carbon cycle in a tropical eutrophic and human-impacted lagoon (Rodrigo de Freitas Lagoon, Brazil). Samples were collected daily at a fixed point to assess short-term temporal variations and at six different stations to assess spatial variability. Water samples were incubated using 14C-bicarbonate at 100% of light and in the dark to quantify photosynthesis and dark carbon fixation, respectively; and 3H-leucine incubations were performed to measure bacterial production. Environmental parameters (temperature, salinity, dissolved oxygen, dissolved organic carbon and inorganic nutrients) were measured to characterize the hydrology of the studied area, and to evaluate their influence on the microbial production rates. There were no significant changes in production rates over time or within different depths. Bacterial production rates varied significantly over space, and were correlated with nitrogen compounds, temperature, salinity and pH. However, a short rainfall event, although not strong or extreme, promoted rapid changes in the shallow water column, such as a decrease in temperature and nitrogen compounds, inducing responses to microbial production rates, such as higher rates of dark carbon fixation and bacterial production at the bottom and lower rates of photosynthesis. Heterotrophic bacterial production was significantly higher than dark and light carbon fixation, being the most important carbon-cycling process in Rodrigo de Freitas Lagoon, possibly favored by the high allochthonous organic matter and nutrient inputs. This study showed that, on average, dark carbon fixation accounted for 30% at the surface and 43% near the bottom of the total primary production and up to 10% of heterotrophic production in the water column, which may be related to the availability of ammonia and methane. We concluded that, even for this short-term temporal and spatial assessment, dark carbon fixation is relevant, although usually disregarded, and this process should be taken into account when evaluating carbon budgets, metabolic balance and ecosystem functioning in tropical coastal lagoons. • Heterotrophic bacterial production prevailed in tropical coastal lagoon. • Bacterial production rates increased with increasing nutrients. • Primary production did not change significantly over short time periods. • Dark carbon fixation contributed between 30 and 43% of primary production. [ABSTRACT FROM AUTHOR]