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Amvrakikos Gulf and its surrounding coastal lagoons are of primary importance for the local biodiversity and fishing activities. Fish species inhabited the coastal lagoons based on the seasonal ongoing migration movements of fry and adult fish individuals from the sea towards the lagoons. Information on the early stages of fish and decapod species in the Amvrakikos Gulf is limited only to the planktonic ontogenetic stages and reproduction biology, respectively. The aim of this study was to describe the spatial distribution of fry from commercially important fish and decapod species in the coastal zone of Amvrakikos Gulf. The seasonal appearance of the early stage of the most commercially important fish species caught in the coastal zone of the gulf ranged from one to four seasons, depending on the species. Individuals of all ontogenetic stages (fry, juveniles, and adults) were reported for several species (A. boyeri, A. fasciatus, S. abaster, S. tyfle, and B. ocellaris), indicating that these species may be regarded as residents in the coastal zone, providing habitats for their entire life cycle. The average relative abundance of the species/genera exhibited no differences compared to other Greek brackish waters. The species composition in the Amvrakikos Gulf at 10 cm and above was in agreement with the transitional nature of the area, with permanent and occasional species present. The present study emphasizes the importance of the coastal zone as a nursery habitat for commercially important species. [ABSTRACT FROM AUTHOR]

Historically, the Antillean manatee (Trichechus manatus manatus) was distributed along the coastline comprised by the five Mexican states that border the Gulf of Mexico. However, the few healthy populations that currently exist in Mexico are now limited to relatively isolated regions with very specific habitat characteristics. In the state of Veracruz, a limited number of individuals are found in the Alvarado Lagoon System (ALS), located in the coastal zone of southern central Veracruz. The aim of this study was to characterize manatee habitat in the ALS. Transects were established in the ALS and 503 points selected and sampled along these transects, producing data pertaining to salinity, depth, dissolved oxygen, total dissolved solids, surface water temperature, pH, bottom type, and conductivity. A total of 45 outings were conducted, with a total sampling effort of 332.36 h. The average physicochemical parameters found were as follows: salinity 3.33 ppm, total dissolved solids 0.51 g/l, temperature 26.29 °C, dissolved oxygen 0.51%, pH 7.55, and oxidation–reduction potential 417.04 mV. Thirteen manatees were observed, mostly (84.6%) during the cold, where the parameters of electrical conductivity, salinity, total dissolved solids, dissolved oxygen, temperature, and oxidation–reduction potential showed differences between the sampled seasons, and in the lagoons with a presence of the floating and submersible vegetation species that form part of manatees' diet. This study shows that the ALS presents lagoons that favor the presence of the Antillean manatee, further narrowing the distribution of the species within the same ALS in the southern central zone of the state of Veracruz. [ABSTRACT FROM AUTHOR]

Mexico has a great variety of aquatic ecosystems; however, most of them present significant contamination levels. Despite the efforts to monitor toxic and bioaccumulative persistent pollutants, they are still insufficient and outdated data from Mexican coasts, especially in polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs), due to the number of aquatic bodies that have received little or no attention. In this regard, the Mexican Pacific's coastal zones and their aquatic ecosystems monitoring PCBs and PAHs in biota is critical because it allows us to estimate the potential risk to human health. This work aimed to determine the total concentration of polychlorinated biphenyls (SPCBs) and total polyaromatic hydrocarbons (SPAHs) in the muscle of fish collected in two coastal lagoons of the central Mexican Pacific and to determine the noncarcinogenic risk ratio (HQ) based on the monthly per capita consumption of national fish and the consumption of fish associated with fishing communities in Mexico. It was found that the potential risk for fishing communities is considerably higher and correlates to the rate of fish consumption, highlighting their vulnerability to these contaminants. [ABSTRACT FROM AUTHOR]

This contribution presents estimates of nutrient fluxes and net metabolism in a pristine coastal lagoon of the Gulf of California. During spring, water variables were sampled in the lagoon and the adjacent sea. The biogeochemical model proposed by the LOICZ program (Land-Ocean Interactions in the Coastal Zone) estimated the nutrient fluxes and the net metabolism of the ecosystem. The water renewal rate was 3 days. The El Soldado lagoon functioned as a source of nitrogen (+61 mol day-1) and as a phosphorus basin (-42 mol day-1). The net metabolism was autotrophic (73 mmol C m² month-1) and dominated nitrogen fixation. These observations in the El Soldado lagoon, help to understand the biogeochemical processes and show the importance of their monitoring throughout the annual cycle, as well as in long term periods. [ABSTRACT FROM AUTHOR]

Evaluating the sources of nutrient inputs to coastal lagoons is required to understand the functioning of these ecosystems and their vulnerability to eutrophication. Whereas terrestrial groundwater processes are increasingly recognized as relevant sources of nutrients to coastal lagoons, there are still limited studies evaluating separately nutrient fluxes driven by terrestrial groundwater discharge and lagoon water recirculation through sediments. In this study, we assess the relative significance of these sources in conveying dissolved inorganic nutrients (NO 3 − , NH 4 + and PO 4 3− ) to a coastal lagoon (La Palme lagoon; France, Mediterranean Sea) using concurrent water and radon mass balances. The recirculation of lagoon water through sediments represents a source of NH 4 + (1900–5500 mol d −1 ) and PO 4 3− (22–71 mol d −1 ), but acts as a sink of NO 3 − . Estimated karstic groundwater-driven inputs of NO 3 − , NH 4 + and PO 4 3− to the lagoon are on the order of 200–1200, 1–12 and 1.5–8.7 mol d −1 , respectively. A comparison between the main nutrient sources to the lagoon (karstic groundwater, recirculation, diffusion from sediments, inputs from a sewage treatment plant and atmospheric deposition) reveals that the recirculation of lagoon water through sediments is the main source of both dissolved inorganic nitrogen (DIN) and phosphorous (DIP) to La Palme lagoon. These results are in contrast with several studies conducted in systems influenced by terrestrial groundwater inputs, where groundwater is often assumed to be the main pathway for dissolved inorganic nutrient loads. This work highlights the important role of lagoon water recirculation through permeable sediments as a major conveyor of dissolved nutrients to coastal lagoons and, thus, the need for a sound understanding of the recirculation-driven nutrient fluxes and their ecological implications to sustainably manage lagoonal ecosystems. [ABSTRACT FROM AUTHOR]

A large proportion of estuaries along microtidal wave-dominated coastlines worldwide have entrances that intermittently close to the ocean when tidal currents and fluvial discharge are insufficient to erode sediment delivered onshore by waves. In this study, these systems are termed "intermittently open/closed estuaries" (IOCE) in order to include all estuaries which intermittently close to the ocean. IOCE do not fit neatly into existing generalized estuary classification models and have been traditionally recognized as a single estuary type that constitute a rare subset of wave-dominated estuaries. In this study, 111 estuaries in Victoria, Australia, are used to develop a classification model that delineates between different IOCE types. This was undertaken using historic aerial imagery and quantification of the estuary channel width, catchment area, lagoon dimensions and tidal prism derived from remotely sensed data. Field surveying of entrance morphology was undertaken for a subsample of 35 IOCE characteristic of each section of the coast and which had detailed entrance condition records. Using this subset, IOCE were classified into three distinct types using multiple methods of statistical delineation (non-metric multidimensional scaling, hierarchical cluster analysis and distribution analysis). These three types are: (1) Type A, the largest IOCE which both close and open infrequently but for the longest durations; (2) Type B, medium sized IOCE which open and close several times per year for weekly to monthly durations; and (3) Type C (tidal creeks), the smallest IOCE located specifically in high rainfall, mountainous catchments and which exist in a predominantly open state. The three types of IOCE showed an order of magnitude difference in entrance closure duration as controlled by variations in the catchment area, tidal prism volume, dimensions of the estuarine lagoon and the entrance channel at the mouth. The classification is also applicable to wave-dominated coastlines internationally where IOCE are present. [ABSTRACT FROM AUTHOR]

The challenges associated with managing systems of shallow coastal lagoons along a rapidly evolving coastline are illustrated in a case study of small lagoon systems in Ghana where these important structures are relied on by a range of different stakeholders for a variety of different purposes including fishing, tourism and salt production. Results of some water quality measurements are presented, showing that these lagoons have poor ecological status where they experience either a lack of flushing by the tide, or large amounts of anthropogenic inputs, or both. A vulnerability assessment is applied to the lagoons in question and this reveals a varying degree of threat from climate change to the operation and use of the lagoons. Our understanding of these systems suggests that a set of 1D hydrodynamic models, underpinned by an understanding of the local coastal sediment transport in each case, is appropriate, and could then be used to inform stakeholders and management in decision making. Integrated, broad-ranging management strategies must adapt to the realities of climate change in order to allow the sustainable use of these lagoons in providing economic benefits, ecosystem services, and elements of coastline protection for the benefit of the local and regional population and its economy. [ABSTRACT FROM AUTHOR]

Little is known about composition, diversity, and abundance of microbial communities in environments affected by primary soil salinization, such as coastal lagoon systems. The main objective of this study was to investigate the impact of lagoon salinity, soil type, and land-use on inland soil and groundwater quality, and soil microbial community structure, diversity, and gene abundance, as evaluated by T-RFLP (terminal-restriction fragment length polymorphism) and qPCR (quantitative polymerase-chain-reaction). For this purpose, four sites oriented along a groundwater salinity gradient ( Fogliano lagoon, central Italy) were studied under different recreational, grazing, and land-use conditions. Spatial variability in groundwater attributes was observed depending on salinity and soil electrical conductivity, both influenced by salt intrusion. A comparison of community abundance and number of phylotypes of bacteria, archaea, and fungi across varying soil depths pointed out marked differences across soils characterized by different soil type, land-use, and salinity. The latter significantly affected the microbial population richness and diversity and showed a dominance in terms of bacteria species. Our study provides a comprehensive overview of the spatial relationship between soil microbial community and soil degradation processes along a relatively underexplored environmental gradient in a coastal system, coming to the conclusion that salinity acts differently as a driver of microbial community structure in comparison with other saline environments. [ABSTRACT FROM AUTHOR]

This study reports the concentrations of the priority pesticides (PPs) in 14 surface sediments and 21 layers of a sediment core from Óbidos Lagoon, a shallow Portuguese coastal lagoon. Results show that the PPs are confined to the upper part of the lagoon that receives most of the inputs from surface runoff of the surrounding agricultural fields and from small tributaries. Past and recent applied PPs were registered in sediments, aluminum normalized concentrations varying between 0.05 × 10 − 7 and 6.85 × 10 − 7 . The PP risk assessment based on sediment quality guidelines like the “Probable Effect Level” (PEL) shows no biological effects in either sediments or aquatic organisms of Óbidos Lagoon, except for dieldrin, lindane, DDT, heptachlor epoxide and its parent compound heptachlor. [ABSTRACT FROM AUTHOR]

Coastal lagoons are ubiquitous along coastlines worldwide. Here, we compare the abundance of epifauna, seagrass-associated macroinvertebrates, and small fish across a gradient of seagrass cover in shallow coastal lagoons of the northern Gulf of Mexico. Two of the lagoons had little or no seagrass cover (0-18.8 %), and four had high cover (83.8-97.5 %). All of the lagoons were partially covered with fringing marsh. We hypothesized that, due to habitat redundancy between seagrass beds and fringing marshes, seagrass-associated fish and macroinvertebrates would not be largely reduced despite the large differences in seagrass cover among the lagoons. Our results support this hypothesis. For most sampling dates, we did not find significant differences in fish and macroinvertebrate abundance among the lagoons and, when we did, several highly vegetated lagoons did not have larger abundances than sparsely vegetated lagoons. The extreme shallowness of the lagoons studied (<1 m) may also provide further protection from large predatory fishes in the absence of seagrasses. Our results also suggest that marsh detritus, by providing habitat for epifauna and helping maintain prey availability, may further temper reductions in seagrass-associated fishes and macroinvertebrates following seagrass decline. The results highlight the importance of marsh-bordered, shallow lagoons as habitat for small fish and macroinvertebrates regardless of seagrass cover. This study contributes to the characterization of habitat redundancy in coastal ecosystems and pinpoints the importance of considering all habitats in concert for the proper understanding and management of coastal ecosystems. [ABSTRACT FROM AUTHOR]

Sea-level rise (SLR) poses a particularly ominous threat to human habitations and infrastructure in the coastal zone because 10% of the world's population lives in low-lying coastal regions within 10 m elevation of present sea level. There has been much discussion about projected (and the sources of projection) vs. measured SLR rates. Which rates should coastal scientists and managers apply in their studies, and what is the degree of confidence of such forecasts, are still open questions. This paper reviews the patterns and effects of relative SLR (RSLR) in coastal lagoons. Three main components are presented in the review: (a) a summary of the main approaches used in predicting medium- to long-term trends in RSLR, (b) a summary of the main evolutionary trends of coastal lagoons and the tools used to examine such trends, and (c) an identification of future research needs. The review reveals that the major source of uncertainty is how and when RSLR will manifest itself at different spatio-temporal scales in coastal lagoon systems, and how its effects can be mitigated. Most of the studies reviewed herein articulate a natural ‘defence’ mechanism of barriers in coastal lagoons by landward barrier retreat through continuous migration, and a gradual change in basin hypsometry during the retreat process. So far, only a relatively small number of detailed studies have integrated and quantified human impacts and coastal lagoon evolution induced by RSLR. We conclude that much more research about adaptation measures is needed, taking into consideration not only the physical and ecological systems but also social, cultural, and economic impacts. Future challenges include a downscaling of SLR approaches from the global level to regional and local levels, with a detailed application of coastal evolution prediction to individual coastal lagoon systems. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrate communities and environmental conditions were studied in two intermittently closed and open coastal lakes and lagoons (ICOLLs), located in southern Algarve (Foz do Almargem e Salgados), with the purpose of evaluating the effects of organic pollution, originated mainly from wastewater discharges, and the physical stress caused by the irregular opening of the lagoons. Most of the year, lagoons were isolated from the sea, receiving the freshwater inputs from small rivers and in Salgados, also from the effluents of a wastewater plant. According to environmental and biotic conditions, Foz do Almargem presented a greater marine influence and a lower trophic state (mesotrophic) than Salgados (hypereutrophic). Benthic macroinvertebrate communities in the lagoons were distinct, just as their relations with environmental parameters. Mollusca were the most abundant macroinvertebrates in Foz do Almargem, while Insecta, Oligochaeta and Crustacea were more relevant in Salgados. Corophium multisetosum occurred exclusively in Salgados stations and, just as Chironomus sp., other Insecta and Oligochaeta, densities were positively related to total phosphorus, clay content and chlorophyll a concentration in the sediment, chlorophyll a concentration in water and with total dissolved inorganic nitrogen. Abra segmentum, Cerastoderma glaucum, Peringia ulvae and Ecrobia ventrosa occurred only in Foz do Almargem, with lower values of the above mentioned parameters. Both lagoons were dominated by deposit feeders and taxa tolerant to environmental stress, although in Salgados there was a greater occurrence of opportunistic taxa associated to pronounced unbalanced situations, due to excess organic matter enrichment. [ABSTRACT FROM AUTHOR]

Coastal lagoons have long been subjected to anthropogenic disturbances due to the increasingly urbanization pressure along the margins. As a result, the composition, structure and distribution of macrozoobenthic communities are strongly affected by environmental gradients and harsh ecological conditions. This study address the first signs changes in the Piratininga-Itaipu lagoon system, located in the southeastern Brazilian coastline, state of Rio de Janeiro, after the opening of a tidal channel in the most deteriorated area of Piratininga lagoon in April 2008, as part of restoration measures concerning the severe eutrophication of this system. In order to observe changes in environmental conditions and community structure before and after the channel opening, sampling of the benthic macrofauna and abiotic variables were conducted in seven sites, from August 2007 to March 2009. According to statistical tools, no significant differences were shown in both environmental characteristics and community structure before and after the channel at the distinct locations. Nevertheless, local changes in the abundance and composition of species were detected particularly in Piratininga, in the site where the tidal channel was constructed. A remarkable loss in abundance of most opportunistic species and the appearance of six new taxa in Piratininga after the opening of the channel was related to habitat regeneration in virtue of the intrusion of marine waters into the lagoon. However, marine inflow seems to be restricted since no clear evidence of the channel influence was felt in the remaining sites of Piratininga and in Itaipu. Macrobenthic communities were heterogeneous between both lagoons throughout the sampling period, characterized by low diversity and evenness indices. A general increase in salinity and redox potential were observed in Piratininga. Both variables allied to dissolved oxygen appeared to play a major role in structuring the benthic communities. This study is the first contribution to knowledge of taxonomic biodiversity of macrozoobenthic assemblages of Piratininga-Itaipu lagoon system and pioneer in describing apparent ecosystem ameliorations after the channel opening. Therefore, continuous monitoring ought to be carried out in order to evaluate the effectiveness of the tidal channel and follow further recovery of this ecosystem. Macrobenthos were quite heterogeneous between both lagoons throughout the sampling period, with biological attributes showing a remarkable loss in species abundance, mostly opportunistic. The appearance of new taxa, Polydora cornuta, after the opening of the channel was related to improvement of better oxygenation of water and sediments, causing regeneration of habitat. Other resilient taxa with persistant bioturbation activities, such as Allita, Streblospio, Capitella and oligochaetes, dominated the early stages of recovery. This study is the first contribution to knowledge of taxonomic biodiversity of macrozoobenthic assemblages of Piratining-Itaipu lagoon system and pioneer in describing apparent ecosystem ameliorations after the channel opening. Therefore, continuous monitoring ought to be carried out in order to follow further recovery of this ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Coastal lagoons are very heterogeneous systems covering a wide range of physiographical and hydrological characteristics. The hypothesis of the present investigation was that physiographical and hydrological characteristics of coastal lagoons affect their physico-chemical properties and their buffering capacity against nutrient enrichment. We compared data collected during a complete annual cycle in six coastal lagoons which were representative of the different lagoon types proposed by Kjerfve (1986) and were subjected to different anthropogenic pressures. The greater exchange of water with the sea in the leaky lagoon of Ria Formosa (type 3) reduced the seasonal differences in the physico-chemical variables and increased the buffer capacity against nutrient enrichment when compared to the restricted (type 2) and chocked (type 1) lagoon types. The lagoon types also showed important differences regarding nutrient limitation, with types 1 and 2 being P-limited and type 3 being N-limited. Our approach can be applied to other coastal lagoons representative of transitional water types in order to provide a general framework for the rational management and policy strategies of coastal lagoons. [Copyright &y& Elsevier]

Abstract: The analysis of the contribution of a food source to a consumer''s diet or the trophic position of a consumer is highly sensitive to the variability of the isotopic values used as input data. However, little is known in coastal lagoons about the spatial variations in the isotopic values of primary consumers considered ‘end members’ in the isotope mixing models for quantifying the diet of secondary consumers or as a baseline for estimating the trophic position of consumers higher up in the food web. We studied the spatial variations in the δ13C and δ15N values of primary consumers and sedimentary organic matter (SOM) within a selected area of the Cabras lagoon (Sardinia, Italy). Our aim was to assess how much of the spatial variation in isotopic values of primary consumers was due to the spatial variability between sites and how much was due to differences in short distances from the shore. Samples were collected at four stations (50–100 m apart) selected randomly at two sites (1.5–2 km apart) chosen randomly at two distances from the shore (i.e. in proximity of the shore –Nearshore – and about 200 m away from the shore –Offshore). The sampling was repeated in March, May and August 2006 using new sites at the two chosen distances from the shore on each date. The isotopic values of size-fractionated seston and macrophytes were also analyzed as a complementary characterization of the study area. While δ15N did not show any spatial variations, the δ13C values of deposit feeders, Alitta (=Neanthes) succinea, Lekanesphaera hookeri, Hydrobia acuta and Gammarus aequicauda, were more depleted Offshore than Nearshore. For these species, there were significant effects of distance or distance × dates in the mean δ13C values, irrespective of the intrinsic variation between sites. SOM showed similar spatial variations in δ13C values, with Nearshore-Offshore differences up to 6‰. This indicates that the spatial isotopic changes are transferred from the food sources to the deposit feeders studied. In contrast, δ13C and δ15N values of suspension feeders, Ficopomatus enigmaticus and Amphibalanus amphitrite, did not show major variations, either between sites, or between Nearshore and Offshore. These different patterns between deposit feeders and suspension feeders are probably due to a weaker trophic link of the latter with SOM. We suggest that the Nearshore-Offshore gradient might be an important source of isotopic variation that needs to be considered in future web studies in coastal lagoons. [Copyright &y& Elsevier]

Abstract: Global climate change is a reality that is rendering the concept of ‘background conditions’ meaningless. We can no longer attempt to maintain the environmental status quo. What we can do is to attempt to maintain ecosystem services despite climate-driven environmental change. There is a pressing need for proactive management that purposefully changes ecosystems to maintain ecosystem services before uncontrolled, detrimental changes occur. Such management would go beyond the bounds of current management efforts and could include, for example, introduction of species, bioengineering, and physical engineering. I suggest that this approach be applied first to coastal lagoons as they are clearly defined geographic areas where this approach can, hopefully, be demonstrated such that it can be applied more widely – when it is accepted, which unfortunately will most probably not occur until the adverse impacts of global climate change become much more apparent. [Copyright &y& Elsevier]

During an annual cycle (2002–2003), spatio-temporal differences and/or similarities in phytoplankton communities and their relationship with physical and chemical characteristics were determined in two coastal lagoons on the Mexican South Pacific coast: Chantuto-Panzacola (CHP) and Carretas-Pereyra (CP), Chiapas. Phytoplankton assemblages, characteristic of the two main seasons (dry and wet), were identified using principal component analysis (PCA), while canonical correspondence analysis (CCA) was used to examine environmental variables that may explain the patterns of variation of the phytoplankton community. The results show that both systems have similar characteristics because they have the same physical forcing (river discharge, seawater intrusion and, in general, weather). Spatial variability is especially important because it favors, during each season, the development of two different functional zones: a marine influence zone (MIZ) and a freshwater influence zone (FIZ). Phytoplankton distribution, composition and abundance were influenced by this environmental variation. Based on PCA results, during the dry season, assemblages in these lagoons are mainly comprised of neritic diatoms such as Coscinodiscus spp. and Skeletonema costatum distributed in the MIZ, whereas dinoflagellates of the genus Protoperidinium spp., and brackish diatoms such as Cyclotella sp., Entomoneis alata and Surirella spp., make up FIZ assemblages. CCA analysis indicates that salinity, temperature, dissolved oxygen and ammonium were the most relevant environmental factors affecting the variation in the distribution of these assemblages. On the other hand, during the rainy season, assemblages were correlated with silicate and orthophosphate concentrations, while their composition was dominated by freshwater groups mainly in the FIZ, whereas in the MIZ centric diatoms were dominant. In summary, in CHP and CP coastal lagoons, phytoplankton assemblages undergo changes in species composition and community structure during each season in response to environmental variation, which allows the development of associations specifically adapted to prevailing conditions. [ABSTRACT FROM PUBLISHER]

Abstract: Drana Lagoon, located at the NW site of Evros River Delta, was drained in 1987 and re-flooded in 2004 within the framework of an integrated wetland restoration project. This study presents the results of a monitoring program of the lagoon''s oceanographic, water quality and fish fauna characteristics, during the pre- and post-restoration period. Results depict the presence of high salinity water (up to 41) due to seawater intrusion, strong evaporation in its interior and inadequate freshwater inflows. Overall, nutrient levels were low depicting local changes. Tidal variability at the mouth was approximately 0.2m, producing high velocity tidal currents (up to 0.75m/s). Eleven fish fauna species were collected; seven species were caught in both the inlet channel and the lagoon during the pre-restoration period and nine species in the post-restoration period. Atherina boyeri (37.6%) and Pomatoschistus marmoratus (31.7%) dominated the lagoon during the post-restoration period. Most of the A. boyeri specimens (88.5%) were caught inside the lagoon, while P. marmoratus had an almost equal distribution in the inlet channel and the lagoon (56.3% and 43.7% respectively). The presence of species of the Mugilidae family (5.2% total average catches after lagoon re-flooding) was mainly in the inlet channel (12.6% of the average catches) and not inside the lagoon (only 1.3% of the average catches). The small number of fish species inhabiting the lagoon might be the result of the recent restoration or it could be related with the increased water flow observed at the lagoon mouth during the flood and ebb tidal phases, and also in the presence of a smooth bank in the concrete waterspout that connects the entrance channel with the lagoon. The limited presence of the Mugilidae juveniles inside the lagoon could be related to the prevailing tidal inlet dynamics (i.e. strong ebb flow at lagoon inlet), thus preventing the species to enter the lagoon. In order to restore the lagoon environment, careful and gradual steps should be undertaken under the basis of continuous monitoring of hydrologic, environmental and fisheries system''s status. [Copyright &y& Elsevier]

Abstract: The effects of a disturbance by sandbar opening on the zooplankton community were evaluated through a long-term study in an eutrophic and oligohaline system, Imboassica Lagoon, Rio de Janeiro, Brazil. Zooplankton samples and limnological data were collected monthly from March 2000 to February 2003. Before the sandbar was opened in February 2001, the lagoon showed eutrophic conditions, with high mean nutrient concentrations and low salinity (total nitrogen – TN=190.28μM, chlorophyll a content – Chl. a =104.60μg/L and salinity=0.87′). During this period, the zooplankton species present, such as the rotifers Brachionus calyciflorus and Brachionus havanaensis, were typical of freshwater to oligohaline and eutrophic environments. After the sandbar opening, the lagoon changed to a lower trophic status and increased salinity (TN=55.11μM, Chl. a =27.56μg/L and salinity=19.64′). As a result, the zooplankton community came to consist largely of the rotifer Brachionus plicatilis, marine copepods and meroplanktonic larvae, mainly Gastropoda. Salinity was the main force structuring the zooplankton community after the sandbar opening. Two years after this episode, the prior zooplankton community had not reestablished itself, indicating a low resilience to this disturbance. The conditions developed prior to a sandbar opening can be crucial to the community responses in the face of this disturbance and for the capacity of the original zooplankton community to re-establish itself. [Copyright &y& Elsevier]

We present 137Cs profiles for three low lying coastal lagoons in Southwest England that show a decline in activity with sediment depth. 137Cs inventories are lower than expected by comparison with local reference inventories despite the fact that sampling was undertaken in the deep-water zone of each lake where sediment and 137Cs focusing would be expected. At all three locations, lake sediment 7Be and unsupported 210Pb (210Pbun) inventories are not significantly lower than the local reference inventory. 137Cs inventories in the study cores range from 38 to 95% of local reference inventories. The standing water level and mud: water interface at two sites are below maximum tide level and, at all three sites, salinity increases significantly in the water columns between low and high tide and in the pore waters of the underlying sediments. We suggest that the difference in hydrostatic pressure between sea level and standing water levels in the lagoons forces salt water up through the sediment column and that monovalent cations (especially Na+ and K+) replace 137Cs on exchange sites leading to the upward migration and loss of 137Cs. Rising sea levels may therefore contribute to remobilisation and release of 137Cs to the aquatic environment from the sediments of coastal lagoons. [ABSTRACT FROM AUTHOR]

The mouth dynamics of small temporary open estuaries play a key role in their overall functioning. Intermittent breaching of the sand barriers of these systems leads to large changes in the physico-chemical environment, which in turn triggers major biological responses. The breaching process can also cause significant morphological changes because the strong breach outflows can scour large quantities of accumulated sediments from an estuary. Simple laboratory experiments are reported that aim to understand what determines the size of a breach in the sand barrier. The experiments were specifically designed to test the influence of storage volumes on the breaching process. They suggest a remarkably simple result that the breach width scales on the 1/3 power of the total volume of water that flows through the breach. This scaling is shown to be consistent with breaching at actual estuaries (or coastal lagoons) where storage volumes are six orders of magnitude higher than the models. Furthermore, a review of data from earth dam failures also reveals a broad consistency with the scaling deduced from these model tests. [ABSTRACT FROM AUTHOR]

Polychiorinated biphenyl (PCB) congener concentrations and organic matter content were determined in 84 samples of suspended and settled sediments collected from six different locations in the Ria Formosa lagoon (Portugal). Total PCB (tPCB) concentrations were higher in the suspended matter (1.00-39.80 ng g-1 dw) than in the sediments (0.10-2.10 ng g-1 dw) and, in general, the same was true for the organic matter. Partial least squares (PLS) analysis using the suspended sediments as signatures indicated that they better explained the settled sediment pattern compared to the reverse. This suggests a suspended sediment source outside the lagoon as source of these PCBs. PLS analysis also indicated that Aroclor 1242 best explained the congener pattern in the sediments, but lower fits were obtained for the suspended matter. The tri- and tetra-chlorinated biphenyls were the most abundant congeners (about 60% of tPCB), followed by the hexa- (20%), penta- (11%) and hepta + octa-chlorobiphenyls (9%). The principal congener differences between the suspended and settled sediments were for the smaller tri- and tetra- chlorinated biphenyls, which were preferentially accumulated in the settled sediments. In contrast, congener 49 was significantly more abundant in the suspended phase and may be formed through the anaerobic UV degradation pathway either in suspension or on the surface of strongly anoxic sediments at low tide. [ABSTRACT FROM AUTHOR]

Mexico has two main types of coasts, an Amero-trailing-edge coast along the Gulf of Mexico and a collision coast along the Pacific, each of which determine the characteristics of their coastal lagoons. The lagoons along the Gulf of Mexico are extensive, tropical and rich in seagrass beds and mangroves, and among these Laguna Madre has 84 species of fishes. In contrast, the lagoons along the Pacific are small, closed, mostly oligohaline and usually lack seagrass beds, and among these Laguna Salinas del Padre has 19 species of fishes. This marked difference in species richness, in turn, has a direct effect on the size and value of the fisheries, as these are regional in the first case and local and seasonal in the second. Copyright 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]

The dynamics of macrophytic and macrozoobenthic communities were studied during two consecutive years in three French lagoons with differing degrees of eutrophication: (1) Arcachon Bay, a macrotidal lagoon on the Atlantic coast; (2) the fishponds of Certes, an almost enclosed system adjacent to Arcachon Bay; and (3) the Etang du Prévost, a highly eutrophic Mediterranean lagoon experiencing summer dystrophic crises. Two stations were sampled seasonally in each system. The intertidal area of Arcachon Bay was covered by a dense, stable seagrass (Zostera noltii) bed. In terms of abundance, macrofauna were dominated by oligochaetes, which could be related to the high below-ground plant biomass, including slow-decaying debris; faunal biomass remained relatively constant, throughout the study period. In the Certes lagoons, which were intermediate between the other two systems in terms of eutrophication, vegetation was dominated by another rooted phanerogam (Ruppia cirrhosa) with fairly constant biomass, while sporadic development of green macroalgae occurred in spring; both biomass and species richness of macrofauna were low. In the Prévost lagoon, macrophytes were opportunistic macroalgae that first proliferated and then disappeared over a short period in summer; this seasonal crisis resulted in a marked decrease in both biomass and abundance of macrozoobenthos. Macrobenthic dominance shifted after the first summer from suspension-feeding bivalves to subsurface deposit-feeding annelids. The differences in structure and seasonal dynamics of benthos in the three systems may have significant effects on higher trophic levels. [ABSTRACT FROM PUBLISHER]

Gialova Lagoon, a coastal marine ecosystem in the Ionian Sea, suffered the impact of an oil spill incident in October 1993, leading to the extensive fish deaths when the oil tanker “Iliad” hit bottom in the entrance of the neighbouring Navarino Bay. A multidisciplinary study investigating the structure and functioning of Gialova Lagoon for the development of an integrated economic, social, and environmental management policy consistent with its conservation was carried out on a seasonal basis during 1995/1996. One of the research priorities was to investigate the structure and dynamics of the macrozoobenthic communities and assess whether these communities had recovered from the impact of the oil spill. The various methods applied (abundance/biomass comparison, distribution of species in geometric abundance and geometric size classes) revealed no detectable disturbance of the macrobenthic communities due to anthropogenic impact. However, it was proved that the lagoonal macrofauna suffered extreme natural disturbance due to a dystrophic crisis that occurred during autumn although they successfully recovered in subsequent seasons. Different sets of environmental factors were found to be highly correlated with the temporal and spatial distribution pattern of the macrobenthic communities and are discussed in detail. The coenocline observed in Gialova Lagoon appears to be strongly correlated with the degree of water exchange with adjacent marine and continental environments. [ABSTRACT FROM PUBLISHER]

Coastal lagoons and dunes are of great ecological importance, not only for providing habitats for rare flora and fauna, but also for protecting coastal areas from rising sea levels and storms, etc. Even though these features are unique for sustainable development and are extremely important to the natural environment and economy, they are one of the most vulnerable and threatened ecosystems due to their small size. The western coasts of Naxos (central Aegean Sea) represent an example of such phenomena, with various wetlands bordered by low-lying sand dunes. The aim of our study is to assess the vulnerability and pressures of the western coasts of Naxos Isl. by taking into consideration both natural and anthropogenic factors. We used a variety of approaches for the environmental and geomorphological study of the coastal zone to achieve this goal, including: (a) study of aerial photography from 1960 until today, (b) systematic seasonal aerial monitoring by drone, since 2015, (c) use of DGPS for the mapping of the coastal zone and for obtaining detailed topographic sections, and (d) dune mapping. Our findings reveal the vulnerability of the western coasts of Naxos due to sea level rise, tectonic subsidence, and a variety of anthropogenic pressures, such as uncontrolled parking, vegetation uprooting, sand extractions, and heavy touristic traffic. Therefore, the protection of the sand dunes, their restoration where they have been eroded, the definition of a zone of control, and restriction of human activities must be a key priority. [ABSTRACT FROM AUTHOR]