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Taxonomic Sufficiency (TS), the use of coarser taxonomic resolution in monitoring plans, has been receiving increasing attention in last years. A comprehensive dataset of macrobenthos from 18 Italian lagoons in a range of different latitude, typology, salinity and surface area, was analysed in order to test the efficiency of TS, in terms of correlation between patterns at level of species and patterns resulting from different levels of taxonomic aggregation. First, TS was applied on a range of univariate indices, providing complementary information on macrobenthic community, in order to test the efficiency, in a contest of different taxonomic composition, and different number of lower taxa belonging to the same higher taxon in each lagoon. Then, TS was applied on multivariate analyses, in order to test whether the efficiency changes between two different scales: local (comparison of sites nested within each lagoon) and regional (comparison among lagoons), and with different data transformation. The patterns resulting from univariate indices and multivariate analyses, at both local and regional scales, were retained till family level, despite the different levels of taxonomic composition and different number of lower taxa belonging to the same higher taxon of different lagoons. Nevertheless, the correlation values among matrices and the effect of data transformation differed between regional and local scales. Our results support the efficiency of TS until family level, but at the same time underline the need of scale- and region-specific baseline knowledge prior application of TS in lagoons., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Lagoons are naturally enriched habitats, with unstable environmental conditions caused by their confinement, shallow depth and state of saprobity. The frequent fluctuations of the abiotic variables cause severe changes in the abundance and distribution of biota. This relationship has been studied extensively for the macrofaunal communities, but not sufficiently so for the bacterial ones. The aim of the present study was to explore the biodiversity patterns of bacterial assemblages and to examine whether these patterns are associated with biogeographic and environmental factors. For this purpose, sediment samples were collected from five lagoons located in the Amvrakikos Gulf (Ionian Sea, Western Greece). DNA was extracted from the sediment and was further processed through 16S rRNA pyrosequencing. The results of this exploratory study imply that salinity is the environmental factor best correlated with the bacterial community pattern, which has also been suggested in similar studies but for macrofaunal community patterns. In addition, the bacterial community of the brackish lagoons is differentiated from that of the brackish-marine lagoons. The findings of this study indicate that the studied lagoons have distinct bacterial communities., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The present work, which has been carried out in the framework of EEA project BLUE-GREENWAY, is a contribution to the study of the evolution of hypoxia/ anoxia in Aitoliko lagoon, Greece. The study area suffers from anoxia which is a very important environmental problem lately mainly due to anthropogenic activities. Unpublished data from two measurement campaigns (2013–2014, 2023) have been used, and a 3D ocean model (SINMOD) has been configured for the region, that couples hydrodynamics, biochemistry and ecology. The analysis of model results includes monthly, annual and interannual variability of fields of dissolved oxygen, temperature, salinity, density, currents and wind as well as Brunt-Väisala frequency and Richardson number. Main results concerning oxygen are: a) the lagoon shows anoxic behavior at 5–7 m depth with a seasonal dependence, b) the seasonal variability in the upper water column with deeper ventilation during winter when the surface stratification is weaker than that during summer, c) anoxic water is reaching the surface of the lagoon for a short period of time. [ABSTRACT FROM AUTHOR]

Rapid changes in sea ice extent and changes in freshwater inputs from land are rapidly changing the nature of Arctic estuarine ecosystems. In the Beaufort Sea, these nearshore habitats are known for their high productivity and mix of marine resident and diadromous fishes that have great subsistence value for Indigenous communities. There is, however, a lack of information on the spatial variation among Arctic nearshore fish communities as related to environmental drivers. In summers of 2017–2019, we sampled fishes in four estuarine ecosystems to assess community composition and relate fish abundance to temperature, salinity, and wind conditions. We found fish communities were heterogeneous over larger spatial extents with rivers forming fresh estuarine plumes that supported diadromous species (e.g., broad whitefish Coregonus nasus), while lagoons with reduced freshwater input and higher salinities were associated with marine species (e.g., saffron cod Eleginus gracilis). West–East directional winds accounted for up to 66% of the community variation, indicating importance of the wind-driven balance between fresh and marine water masses. Salinity and temperature accounted for up to 54% and 37% of the variation among lagoon communities, respectively. Recent sea ice declines provide more opportunity for wind to influence oceanographic conditions and biological communities. Current subsistence practices, future commercial fishing opportunities, and on-going oil and gas activities benefit from a better understanding of current fish community distributions. This work provides important data on fish spatial distributions and community composition, providing a basis for fish community response to changing climatic conditions and anthropogenic use. [ABSTRACT FROM AUTHOR]

Although the effect of salinity on phytoplankton community structure has been studied in many coastal lagoons at different times, it has not been studied simultaneously in different lagoons that are not on the same delta but are geographically close to each other. In the present study, the effect of temporal and spatial changes in salinity on the phytoplankton biovolume, species richness, diversity, and species composition was investigated seasonally in 2020 and 2021 in 6 coastal lagoons of Marmara Basin (Türkiye). In more saline lagoons, phytoplankton biovolume, species richness, diversity, and the total number of species were lower. In lagoons which salinity values were approximate, the species composition was similar. Although the salinity in the lagoons did not show significant change seasonally, biovolume values were lower in Mert lagoon in the fall of 2020 when the salinity values were higher compared to the spring of 2021. Moreover, the considerable decrease in salinity shifted the dominant species structure from high salinity optima species to low salinity optima species in this lagoon. Other effective parameters in the seasonal distribution of dominant species were detected as temperature, dissolved oxygen, alkalinity, and nitrate nitrogen. [ABSTRACT FROM AUTHOR]

Araruama Lagoon is one of the world's largest permanent hypersaline lagoons, and knowledge about the reproduction of fish assemblages is very scarce. This study aimed to evaluate the reproductive functionality of fishes of the Araruama Lagoon in the seasons of 2011, using functional diversity metrics. We also assessed the influence of abiotic factors (salinity, temperature, dissolved oxygen, and pH) on the distribution of sexes and reproductive stages of fish assemblages. Gonads were analyzed in 709 fish across 18 species, mainly females and juveniles. In winter, when there was a lower abundance of species, the highest reproductive incidence (gonadal development/maturation) and high salinity occurred. Summer and spring corresponded with the highest percentage of juveniles. Salinity was the abiotic factor behind the structuring of the community, while the temperature set off the start of the reproductive cycle in autumn. Thus, Araruama Lagoon played a crucial role as a nursery and reproductive area for the fish assemblage. Reproduction in Araruama Lagoon (2011). The vertical arrows indicate the main abiotic variables: temperature and salinity, which structure the fish community. Colors indicate larger (darker) and smaller (lighter) numerical values. The graphs show the percentage of juveniles, males and females, in the seasons corresponding to each season: spring (green), summer (yellow), autumn (orange), and winter (gray). The number of fish next to each graph indicates fish abundance in season, and fish colors indicate diversity. [ABSTRACT FROM AUTHOR]

Introduction: Heterotrophic protists colonizing microbial mats have received little attention over the last few years, despite their importance in microbial food webs. A significant challenge originates from the fact that many protists remain uncultivable and their functions remain poorly understood. Methods: Metabarcoding studies of protists in microbial mats across high-altitude lagoons of different salinities (4.3-34 practical salinity units) were carried out to provide insights into their vertical stratification at themillimeter scale. DNA and cDNA were analyzed for selected stations. Results: Sequence variants classified as the amoeboid rhizarian Rhogostoma and the ciliate Euplotes were found to be common members of the heterotrophic protist communities. They were accompanied by diatoms and kinetoplastids. Correlation analyses point to the salinity of the water column as a main driver influencing the structure of the protist communities at the five studied microbial mats. The active part of the protist communities was detected to be higher at lower salinities (<20 practical salinity units). Discussion: We found a restricted overlap of the protist community between the different microbial mats indicating the uniqueness of these different aquatic habitats.On the other hand, the dominating genotypes present inmetabarcoding were similar and could be isolated and sequenced in comparative studies (Rhogostoma, Euplotes, Neobodo). Our results provide a snapshot of the unculturable protist diversity thriving the benthic zone of five athalossohaline lagoons across the Andean plateau. [ABSTRACT FROM AUTHOR]

Coastal zones have great environmental and economic importance, since anthropogenic activities are very intense, and consequently, their water quality can be affected. Spatial and temporal variations in physicochemical parameters [temperature, pH, electrical conductivity (EC), salinity, dissolved oxygen (DO) and turbidity] in the surface water from the São Lourenço Watershed, a coastal zone in southern Brazil, were investigated. The influence of Patos Lagoon on the watershed in dry periods was confirmed by the increase in salinity and EC of up to 6.43 and 10,810.00 µS cm−1, respectively. In addition, the DO content with low values at the mouth in some samplings, below the Brazilian legislation, calls attention for the water quality. The principal component analysis showed considerable differences in the lower course by comparison with the upper course and the middle course due to climatic and anthropogenic factors. Results from the monitoring enabled to understand fluvial dynamics involving the system of a watershed that contributes to disposal in coastal lagoons through seasonal and climatic factors. Besides, from a managerial point of view, the obtained results support effective decision-making for the preservation of coastal ecosystems. [ABSTRACT FROM AUTHOR]

Short-term zooplankton grazing experiments in bottles were conducted with water from 12 Danish brackish lakes covering a large gradient in salinity (0.3-17.4 ppt) as well as from mesocosms conducted in the same area with various salinities (0.5-12 ppt), two nutrient levels and low fish density (14). However, the ongoing climate change along with the already experienced extremes and a number of anthropogenic activities have increased their salinity at places and/or increased the amplitude of the salinity changes (Lengyel et al., [13]; B-Béres et al., [1]; Cortez et al., [5]). Also, in lentic environments of a drying coastal plain of Southeast Brazil, a comparison between stenohaline (i.e. narrow salinity tolerance ranges) and euryhaline (i.e. wide salinity tolerance ranges) fish species showed non-random patterns of community composition. Incubation under a range of salinities (5-57 ppt) indicated lower photosynthetic performance at increased salinity for both species, which increased their organic osmolyte contents with rising salinity stress. [Extracted from the article]

Mediterranean coastal lagoons are particularly vulnerable to increasing direct anthropogenic threats and climate change. Understanding their potential responses to global and local changes is essential to develop management strategies adapted to these ecosystems. Salinity is a fundamental structuring factor for phytoplankton communities; however, its role under climate change is understudied. We hypothesized that salinity variations imposed by climate change and/or management actions could disturb Mediterranean lagoons' phytoplankton communities. To test our hypothesis, we performed two 5-day microcosm experiments in which natural phytoplankton assemblages from the Santa Giulia lagoon (Corsica Island) were subjected to three increasing (53–63–73) and decreasing (33–26–20) levels of salinity, to mimic strong evaporation and flash flooding, respectively. Results indicate that over-salinization inhibited growth and modified the assemblages' composition. Freshening, on the contrary, showed feeble effects, mainly boosting microphytoplankton abundance and depleting diversity at lowest salinity. In both experiments and under freshening in particular, initially rare species emerged, while photosynthetic activity was degraded by salinity increase only. We demonstrated that phytoplankton communities' structure and metabolism are strongly altered by the predicted implications of climate change. Such impacts have to be considered for future management of coastal lagoons (control of sea exchanges and watershed fluxes). This work constitutes a priority step towards the proactive adapted management and conservation of such as-yet-neglected ecosystems in the context of climate change. [ABSTRACT FROM AUTHOR]

Coastal lagoons are unique ecosystems in terms of their phytoplankton community structure, due to their unstable environment in terms of biological, chemical, and physical conditions as a result of flooding and seasonality. Seasonal and spatial variations in phytoplankton are controlled by various biotic and abiotic factors. In this study, temporal and spatial changes in the phytoplankton biovolume, species richness, diversity, and Reynolds functional groups (FGs) with the effect of different environmental variables were investigated seasonally in 2020 and 2021 for seven coastal lagoons of Kızılırmak Delta (Samsun, Türkiye). Phytoplankton biovolume and species richness were lower in more saline lagoons. Moreover, their species composition was significantly different compared to lagoons with lower salinity. Phytoplankton biovolume, species richness, and diversity were generally recorded lower in spring periods. During the studied periods, 14 FGs (C, D, J, Lo, M, MP, P, S1, S2, SN, W1, W2, X1, and X2) were prominent in the total biovolume. Three FGs (C, P, and SN) were only found as dominant in Karaboğaz, Gıcı, and Cernek lagoons, and their distributions were affected by pH, nitrate–nitrogen, and low light availability (high Zmix/Zeu). Due to the seasonality and hydrology, environmental parameters and dominant FGs were generally segregated into flooding (spring), drying (summer), and transition (fall) periods. [ABSTRACT FROM AUTHOR]

The interaction between tide, river runoff, and wind in coastal lagoons induces complex salinity gradients, which are remarkable when the meteorological forcing is exacerbated. This work aims to characterize the salinity structure under extreme freshwater and wind events in the Ria de Aveiro coastal lagoon (Portugal). The Delft3D model was implemented and validated in 3D mode and used to perform simulations forced with extreme freshwater and wind scenarios. Results show that forcing conditions determine salinity stratification intensity and location. Generally, stratification increases as the freshwater increases, while the salinity intrusion moves downstream. Extreme wind tends to destroy stratification but fails to promote full-depth mixing, which is also dependent on the wind direction, as shown for the Espinheiro channel. The salinity intrusion is also impacted by wind events, being NW storms responsible for an upstream salt transport along the Mira channel and a downstream transport along the Espinheiro channel, and SW storms for an upstream displacement of the salinity intrusion along the São Jacinto channel. Finally, it is observed that the advection of a freshwater plume from the Vouga River into the middle of the São Jacinto channel under high freshwater scenarios causes an unusual local salinity pattern. This plume can either be pushed upstream or prevented from entering the channel, depending on the wind direction. [ABSTRACT FROM AUTHOR]

Coastal lagoons are dynamic transitional water ecosystems hosting valuable biological communities, including rich and diverse macrophyte assemblages. Aquatic macrophytes must cope with large fluctuations of environmental conditions on a spatial and seasonal scale. Salinity is one of the most variable parameters, changing from nearly freshwater to hypersalinity, and it is known to have a strong influence on the composition and structure of macrophyte assemblages. This study is focused on the effect of salinity on macrophyte communities of the eight most important coastal lagoons of Apulia (south-eastern Mediterranean Sea). A set of eleven transitional water body types (sensu Water Framework Directive) were allocated in a range of meso- to hyperhaline lagoons. Macrophyte sampling was carried out between 2011 and 2019, and a total of 324 samples (18 sampling stations × 2 seasons × 9 years) was analyzed. Then, macrophyte occurrence in each transitional water body (T-WB) was expressed as frequency values (%) and assemblages were compared to assess any similarity in relation to four salinity classes (mesohaline, polyhaline, euhaline and hyperhaline). Species richness varied according to the salinity class, being much higher in polyhaline and euhaline T-WBs and strongly decreasing at the extremes of the salinity range (mesohaline and hyperhaline T-WBs). Moreover, the statistical analysis showed a high resemblance of macrophyte assemblages of T-WBs within the same salinity class, which shared a great number of species. Four distinct macrophyte communities were distinguished, reflecting the salinity conditions of different T-WB types and confirming the effectiveness of a lagoon typology based on this descriptor. [ABSTRACT FROM AUTHOR]

The purpose of this work was to investigate the physical and chemical dynamics of Lake Nokoué for its efficient management. For this purpose, two sampling campaigns per month from five stations (North, South, Central, East and West) were conducted for a period of one year (November 2020 to November 2021). Physic and chemical parameters (temperature, salinity, depth, water transparency, pH, dissolved oxygen and total dissolved solids) were measured and wet substrate samples were collected to study the granulometry. Data analysis revealed that Lake Nokoué is mainly affected by two regimes: flooding and low water. Flooding, which is not directly related to rainfall, did not begin until one month after the major rainy season in June. The sources that contributed to the flooding of Lake Nokoué were the freshwater tributaries coming mainly from the Ouèmé River and the flow of the Sô River from August to November. The inflow of fresh water contributed to the decrease in salinity and transparency of the lake from the east to the south. During the low water period (from December to July), Lake Nokoué is characterized by an increase in salinity and transparency from the south to the northeast due to the massive intrusion of sea water into the lake. The highest dissolved oxygen levels are observed in the south and center (5.92 ± 0.46 mg/L) while it varies greatly in the north and west (Eichhornia crassipes concentration zone) during flooding. The average annual depth of Lake Nokoué was 1.47 ± 0.66 m with an average annual pH of 6.85 ± 0.56. [ABSTRACT FROM AUTHOR]

Shallow coastal habitats are ruled by fluctuating environmental conditions, which lead to shifts in fish communities. Functional groups of habitat use and trophic strategy were used to address the responses of fish composition and diversity, since comparisons of rich tropical systems are often complex through species-based approaches. We hypothesized that fish groups will have specific affinities in response to the prevailing environmental conditions, especially those reflecting the prevalence of oceanic or estuarine conditions, where guilds of habitat use would perform better as indicators. Despite the importance of other environmental factors (i.e. temperature and transparency), salinity was the key structuring factor irrespective of the coastal lagoon. Although harbouring the greatest biomass of piscivores, the harsh environmental conditions at Araruama lagoon were related to low diversity. A great number of indicator species, typically of marine affinity, was found at the Saquarema lagoon, probably due to the continuous and broad connection to the sea leading to the predominance of euhaline conditions. Despite the presence of non-native species (i.e. Oreochromis niloticus), the Maricá lagoon function as an important refuge for freshwater groups. Our results stressed the key role played by coastal lagoons of varied water conditions in supporting fish diversity at regional levels. [ABSTRACT FROM AUTHOR]

River estuaries are characterized by mixing processes between freshwater discharge and marine water masses. Since the first are depleted in heavier stable isotopes compared with the marine realm, estuaries often show a linear correlation between salinity and water stable isotopes (δ18O and δ2H values). In this study, we evaluated spatial and seasonal isotope dynamics along three estuarine lagoon transects, located at the northern German Baltic Sea coast. The data show strong seasonality of isotope values, even at locations located furthest from the river mouths. They further reveal a positive and linear salinity‐isotope correlation in spring, but ‐in two of the three studied transects‐ hyperbolic and partially reverse correlations in summers. We conclude that additional hydrological processes partially overprint the two‐phase mixing correlation during summers: aside from the isotope seasonality of the riverine inflows, the shallow inner lagoons in the studied estuaries are influenced by evaporation processes. In contrast the estuarine outflow regions are under impact of significant salinity and isotope fluctuations of the Baltic Sea. Deciphering those processes is crucial for the understanding of water isotope and salinity dynamics. This is also of relevance in context of ecological studies, for example, when interpreting oxygen and hydrogen isotope data in aquatic organisms that depend on ambient estuarine waters. [ABSTRACT FROM AUTHOR]

On the quest of discovering novel local strains of microalgal species that can be effectively cultured with industrial perspectives, two cyanobacterial strains Anabaena sp. and Cyanothece sp. were isolated from the lagoonal and saltworks waters of the Messolonghi lagoon (W. Greece). They were batch cultured at 20–21.5 °C in six combinations of three salinities (20, 40 and 60 ppt) and two light intensities (2000 and 8000 lux) resulting in: (a) Anabaena grew best at 20 and 40 ppt at high light of 8000 lux. (b) Cyanothece grew best at 40 and 60 ppt at high light. (c) Low light of 2000 lux resulted in much reduced growth in all treatments. (d) Maximal biomass yield was 1.27 and 1.77 g d.w./L for Anabaena and Cyanothece, respectively. Overall, both species have culture potential yielding biomass comparable to the average (or above) relevant values reported in the literature for various cultured cyanobacteria. [ABSTRACT FROM AUTHOR]

The Salinas de Chilca are located at km 65 of the Panamericana Sur highway, represented by three lagoons: La Milagrosa (main lagoon and salt ponds), La Mellicera and La Encantada. The environment of these lagoons belongs to the Subtropical Desert (d-ST) life zone. The objective of the present study was to determine the influence of environmental variables on changes in the macroinvertebrate community structure in the Salinas de Chilca, Lima, Peru. Four collection campaigns were carried out from January to September 2018, establishing twelve sampling stations, three stations for each lentic environment. The sample was collected through sweeps with a 500 µm mesh opening type D network on the shore of each lagoon. The physicochemical parameters of the water presented different values in each lagoon and formed a descending salinity gradient from the saline pools (with hypersaline values) towards the La Encantada lagoon (with mesosaline values). 42 genera of macroinvertebrates were collected, with the most influential genera in community patterns: Heleobia, Larsia, Trichocorixa, Ephydra and Artemia, these organisms represented 83.85 % of the total abundance. The environmental gradient generated by salinity determined two very different groups, a group of species that do not tolerate high salinity values (mesosaline lagoons) from another group of species that support extreme salinity values (hypersaline lagoons); however, predation, anthropic alterations, habitat structure, among other factors, would also be influencing changes in the community structure [ABSTRACT FROM AUTHOR]

Coastal lagoon is critical habitat for human and provides a wide range of ecosystem services. These vital habitats are now threatened by waste discharge and eutrophication. Previous studies suggest that the pollution mitigation of coastal lagoon relies on the water exchange with open sea, and the role of microbial processes inside the lagoon is overlooked. This study takes the Pinqing Lagoon which is the largest coastal lagoon in Chinese mainland as example. The distribution of nutrients, microbial activity of nitrogen removal and community structure of denitrifying bacteria in sediment are analyzed. The results showed that the nutrient in sediment represented by DIN (1.65–12.78 mg kg−1), TOM (0.59–8.72 %) and TN (0.14–1.93 mg g−1) are at high levels and are enriched at the terrestrial impacted zone (TZ). The microbial nitrogen removal is active at 0.27–19.76 μmol N kg−1 h−1 in sediment and denitrification is the dominate pathway taking 51.44–98.71 % of total N removal. The composition of the denitrifying microbial community in marine impacted zone (MZ) is close to that of ocean and estuary, but differs considerably with those of TZ and transition zone (TM). The denitrification activity is mainly controlled by salinity and pH, and the denitrifying bacterial community composition related to the nutrient parameters of TN, TOM, etc. Our study suggested that the distribution of nutrients, microbial activity of nitrogen removal and community structure in Lagoon are the combined effects of terrestrial input and exchange with open sea. The microbial processes play important role in the nitrogen removal of coastal lagoon. • Pinqing Lagoon sediment nutrients were mainly from the terrestrial input. • Pinqing Lagoon nitrogen removal activity was at a high level and was mainly dominated by the denitrification pathway. • Pinqing Lagoon denitrification activity was affected largely by pH and salinity. [ABSTRACT FROM AUTHOR]

Large lagoons usually show a salinity gradient due to fresh water tributaries with inner areas characterized by lower mean values and higher fluctuation of salinity than seawater-dominated areas. In the Venice Lagoon, this ecotonal environment, characterized in the past by oligo-mesohaline waters and large intertidal areas vegetated by reedbeds, was greatly reduced by historical human environmental modifications, including the diversion of main rivers outside the Venice Lagoon. The reduction of the fresh water inputs caused a marinization of the lagoon, with an increase in salinity and the loss of the related habitats, biodiversity, and ecosystem services. To counteract this issue, conservation actions, such as the construction of hydraulic infrastructures for the introduction and the regulation of a fresh water flow, can be implemented. The effectiveness of these actions can be preliminarily investigated and then verified through the combined implementation of environmental monitoring and numerical modeling. Through the results of the monitoring activity carried out in Venice Lagoon in the framework of the Life Lagoon Refresh (LIFE16NAT/IT/000663) project, the study of salinity is shown to be a successful and robust combination of different types of monitoring techniques. In particular, the characterization of salinity is obtained by the acquisition of continuous data, field campaigns, and numerical modeling. [ABSTRACT FROM AUTHOR]

Salinity changes in transitional water ecosystems are a natural feature, but anthropogenic direct or indirect impacts are drastically altering their equilibrium and, therefore, their biological communities. Females of three species of Palaemonidae shrimps (the invasive Palaemon macrodactylus and the native P. adspersus and P. elegans) were collected in nature and kept in laboratory at salinities 20 and 30. For each species, the reproductive strategy (investment devoted to reproduction) and the reproductive performance (larval output and hatching success) were determined. Significant differences were observed comparing the three species, highlighting an opportunistic r-strategy in P. macrodactylus and P. elegans, while P. adspersus resulted to produce fewer and larger eggs. Palaemon elegans showed a lower hatching success than the other two species, and the size-adjusted larval output appeared to be highly sensitive to salinity variations, with a strong increase under euhaline conditions (salinity 30), while this increase was limited in the other two species. The selected species were used as model organisms to understand which could be the shift in biological communities due to salinity variations. Data suggest that a shift towards euhaline conditions will favor the native populations, while a shift towards mesohaline waters could determine an increase of the invasive shrimps. [ABSTRACT FROM AUTHOR]

The lack of knowledge on the morphological variability in hydrozoan populations has resulted in numerous misidentifications over history. Cladonema radiatum Dujardin, 1843 is characterized by presenting different morphologies in different localities of the world, which has caused many taxonomic confusions within the group. In this study, the morphological variability in a population of C. radiatum is analyzed. The material came from a coastal lagoon in the southern Gulf of Mexico. The samplings were carried out for 3 months in 2017. Salinity, dissolved oxygen, and temperature were recorded at each sampling site. Cladonema radiatum was more abundant and bigger when the lagoon showed the lowest levels of salinity. Six different morphologies were recognized. The presence of gelatinous papillae on the abaxial surface of marginal bulbs and an abaxial arrangement of nematocysts in the shortest branches of the tentacles are features recorded for the first time in the species. These considerations enrich the taxonomic description of C. radiatum and contribute to the knowledge on the taxonomy of Hydrozoa in Mexico. The taxonomy of Cladonema continues to be confusing, and the present work sets a basis for further integrative studies clarifying the morphological boundaries of the genus. However, only integrative works based on the morphology and molecular analyses of the species would be able to decode its cryptic nature. [ABSTRACT FROM AUTHOR]

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Biogeochemical and ecological responses to limited external nutrient loading are poorly understood in tropical semi-enclosed coastal lagoons which are highly influenced by hydrological and salinity regimes. With objectives towards ecosystem sustainability via better management of the nutrient inputs, investigations were carried out to estimate the water, salt, and nutrient budget of "Pulicat" hypersaline coastal lagoon for the year 2018–2019. The budget revealed that the annual rate of precipitation and evaporation are the major driving factors regulating the annual residual flow in the lagoon. Limited exchange of water and material had resulted in a hypersaline condition with high spatial and temporal variation in salinity ranging from 20 to 103. In the absence of external loading, nutrient enrichment by internal compensation had resulted in DIN enrichment. DIN constituents are mainly contributed by ammonia, indicative of remineralisation through benthic regeneration. The extended water residence time and enhanced primary production has converted the inner lagoon into a limited phosphate system. The TRIX index also indicates a decline in the trophic status transforming the lagoon from a mesotrophic to a eutrophic system. [ABSTRACT FROM AUTHOR]

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Reconstructing pre-industrial hurricane activity and aridity from natural archives places modern trends within the context of long-term natural variability. The first reconstruction of Atlantic hurricane activity in Jamaica was based on a sediment record previously obtained from a coastal lagoon. Specifically, an Extended Hurricane Activity (EHA) index was developed from high-resolution geochemical data that linked fluctuations in lake-level changes to rainfall variability associated with hurricane activity. Here, we analyse the same sediment core from which the EHA index was developed to assess the response of biological indicators, namely fossil diatom assemblages and sediment chlorophyll a (chl- a) concentrations, to hydrometeorological events (tropical cyclone-induced precipitation and droughts) over the past ~1500 years. The diatom assemblages responded sensitively to changes in salinity associated with lake-level changes driven by the balance of precipitation and evaporation. Aquatic production (inferred from sediment chl- a, which includes its main diagenetic products) and salinity (inferred from ITRAXTM µXRF chlorine counts) vary inversely following ca. 1300 CE, likely due to enhanced nutrient delivery from freshwater runoff during periods of elevated precipitation. Although the temporal resolution of our biological data is less-well resolved than that of the geochemical record, it generally tracks long-term trends in rainfall variability inferred by the EHA index over the past millennium. This further demonstrates the potential of using biological proxies from coastal lagoons to track past hurricane activity and aridity. [ABSTRACT FROM AUTHOR]

Seven species of seagrass have been found in the Indian River Lagoon (IRL), making it an unusually diverse location at the global scale. From 1994 to 2019, the lagoon-wide distribution of these species reflected variations in temperature, salinity, and the availability of light at depth, which were related to latitudinal differences in hydrology and hydrodynamics along the IRL. In general, species richness was higher near the four southern inlets, and fewer species were found in areas with longer residence times for water. At a finer scale, the distribution of species varied among depths, with the greatest number of species found at mid-depths (~0.4-0.9 m). Prior to 2011, these patterns remained relatively consistent for ~ 40 years, but several, intense and prolonged phytoplankton blooms disrupted them. The areal extent of all seagrasses decreased by over 50%, the offshore ends of canopies moved shoreward and shallower, distributions of species along gradients of latitude and depth were disrupted, and mean percent cover decreased. Major changes in distribution and abundance of seagrasses arose when salinity, temperature, and availability of light at depth exceeded limits derived for each species. These substantial and widespread changes engendered concerns for recovery or rehabilitation of seagrasses in the lagoon. [ABSTRACT FROM AUTHOR]

Anthropogenic impacts in estuarine systems can influence marine mammal habitat use, population dynamics, fitness, and mortality events. The objective was to examine habitat use among the resident common bottlenose dolphin (Tursiops truncatus) population inhabiting the Indian River Lagoon, Florida, and the influences of variation in environmental factors and prey availability in 2003–2015. We utilized photo‐identification surveys, stratified random samples of prey, and environmental variables collected monthly. Kernel density estimation was used to determine the magnitude‐per‐unit area of dolphins across the IRL by wet and dry seasons each year, the values were used as a response variable in classification and regression tree analyses with fish community and environmental variables as predictors. Spatial patterns in dolphin density in the IRL were associated with salinity and dissolved oxygen levels, which are in part associated with freshwater discharges of nutrient and algae laden waters from the region's storm water management system. These findings isolate locations of concern for management of dolphin habitat, and anthropogenic drivers of dolphin distributions requiring further research. [ABSTRACT FROM AUTHOR]

The ongoing debate on the causes and modalities of the Messinian Salinity Crisis (MSC) from 5.971 Ma needs to be implemented by an in-depth knowledge of the events and changes, on a global to regional scale, that have preceded its onset. Here we use palynological (pollen and dinocysts) and micropaleontological (foraminifers and calcareous nannoplankton) quantitative analyses from the Govone sedimentary succession (Northern Italy, western Mediterranean) to reconstruct the cyclical changes in atmosphere, surface, and deep-water hydrographic conditions during the Late Miocene, prior to the onset of the MSC (from ca 6.6 Ma) and across it (up to 5.96 Ma). On land, plant communities were dominated by arboreal life forms typical of warm and humid conditions. However, mid- to high altitude coniferous taxa attest to a sequence of cold to cool conditions, some coinciding with glacial obliquity-controlled phases, notably those across the MSC onset (i.e. TG34 and TG32). Dominant trees were Taxodioideae, especially in freshwater swamps, during warm and humid phases. The latter alternate with relatively less warm, and less humid phases characterised by the reduction of Taxodioideae, according to the precession-controlled sedimentary cyclicity (sapropel-marl couplets). The absence of any significant expansion in the herbaceous cover is evidence of no substantial increases in aridity at insolation minima. In the marine realm, the precession-controlled cycles correspond to prevalent alternations between warm water, oligotrophic (sapropel, insolation maxima) and cool water, eutrophic (marls, insolation minima) conditions. The progressive decrease of oceanic/outer neritic dinocyst taxa, along with a more continuous occurrence of the inner neritic ones, confirm the progressive restriction of Mediterranean and Atlantic connections, despite oceanic influxes, the latest at 6.14 Ma and 6.05 Ma. On the other hand, the occurrence of freshwater episodes, according to dinocysts, does not exclude possible connections with Paratethys, at 6.18 Ma and 6.07 Ma. All calcareous nannoplankton and foraminifera apparently disappear from the sedimentary record before the onset of the MSC, at ca 6.02 Ma; however, dinocysts allow the documentation of the history of pre-evaporitic conditions up to the beginning of the MSC onset, when lagoons, marked by frequent salinity changes, expanded in the inner neritic zone of the Govone intermediate depth basin, during ca 60 kyrs. Plant assemblages attest a long-lasting increase of seasonality (from 6.2 Ma) as well as a peculiar inversion in the dominant vegetal patterns of the sapropel-marl couplets, between ca 6.02 Ma and 5.96 Ma, corresponding to the uppermost four cycles. The significant restriction of the marine environment, after 6.02 Ma, possibly promoted atmospheric changes marked by reduced vs enhanced activity of the Mediterranean storm-track in phase with precession. This, in turn, regulated the amounts of runoff in the Northern Italian sectors from the Alps. • Humid conditions persist across the MSC in the northern Mediterranean. • Broad-leaved evergreen-warm mixed forests extended north of 42°N in the Mediterranean. • Calcareous microfossils vanished from sediments 50 ka before the MSC onset. • Dinocysts trace the aquatic environmental changes across the MSC onset. • Nannobarbophora , a warm acritarch, marks the MSC onset. [ABSTRACT FROM AUTHOR]

Ologe and Badagry Lagoons are important tropical lagoons in Lagos, Nigeria. The water quality and heavy metal concentration were studied for a period of 2 years (Aug. 2016 to Jul. 2018) using standard methods. The least temperature obtained was 28.70±0.05 °C in Ologe Lagoon during the wet season and the maximum recorded was 29.41±0.08 in in Badagry Lagoon during the dry season. During the wet season (May-October) the temperature was steady and similar between the two connecting tropical lagoons. The salinity values vary at different stations in both Lagoon, 0.06 to 0.44 % in Ologe Lagoon and 0.08 to 0.28 % in Badagry Lagoon. Badagry Lagoon showed significant higher values in conductivity, total dissolved solid, chemical oxygen demand, biological oxygen demand, total suspended solid and total hardness across seasons. Heavy metal results showed that except for lead (0.25±0.10 mg/L), Ologe Lagoon had higher concentrations of all examined heavy metals (Zinc, copper, iron, chromium, lead, cadmium, manganese and cobalt) than Badagry Lagoon across season. Furthermore, cadmium, manganese and cobalt were not detected in Badagry Lagoon across season. The two studied connecting Lagoons especially Ologe Lagoon is exposed to dramatic deterioration in its water quality due to different wastes that discharge into the water body. These lagoons are clearly polluted by metals for various utilizations. As a result, the study suggests enforcing the controls on waste discharged into lagoons. [ABSTRACT FROM AUTHOR]

Lagoon systems are more heavily impacted by hurricanes, whereas the relevant storm surge modeling studies have been paid little attention to lagoon systems and the storm-induced exchange in lagoon systems is even less understood. To address this gap, a three-dimensional unstructured grid-based model was configured for the Maryland Coastal Bays, a typical lagoon system with two unique inlets (Ocean City Inlet (OCI) and Chincoteague Inlet (CI)), to investigate how Hurricane Sandy impacted inlet dynamics. A nesting model framework was applied to provide the necessary remote forcing from a large model domain and maintain the intricate shoreline and bathymetry of an inner model domain. Results indicated that the flux patterns varied in response to the change in wind direction and rising/falling high water levels from the coastal ocean, rather than a single flow pattern during the passage of Sandy. From October 29 05:00 to 17:00 UTC, mild (> 10 m/s) and strong (> 15 m/s) northerly winds accompanied by the rising high water level from the coastal ocean promoted a mean inflow pattern at the OCI and a mean outflow pattern at the CI. Strong southwesterly winds (> 15 m/s) dominated in the bays from October 30 03:00 to 15:00 UTC. Under strong southwesterly winds and falling high water levels from the coastal ocean, flux was transported landward at the CI and seaward at the OCI. Sensitivity experiments on various storm temporal scales showed that a net inflow pattern occurred in the bays, and the net exchange amounts became smaller in response to longer storm durations. Residual effect of relatively high river flow from Sandy could still influence the salinity at the OCI, whereas the CI salinity was not affected by river flow owing to a long distance between the CI and river locations. [ABSTRACT FROM AUTHOR]

Coastal tropical shallow lagoons are located at the Central Pacific Coast, South America. Standard cyanobacterial and microalgae collections at Puerto Viejo wetland (Grande lagoon, north of the wetland), Lima department with physical -chemical parameters were registered irregularly between 2005 -2010. Planktic natural populations of Rhabdoderma lineare Schmidle et Lauterborn from summer and fall seasons showed cell and colonial morphological variations. R.lineare bloomed in eutrophic saline conditions, associated with the unicellular rodophyte Porphyridium purpureum (Bory) Drew &Ross. They colonized habitats with temperature range of 25 - 33 °C, salinity gradients between 13 - 20 ppt (NaCl), pH range from 8 to 9. Cyanobacterial and rodophyte phenotypic plasticity and, its distributional patterns (planktic and benthic) in the shallow lagoon are related for viable life strategy for successful colonization of coastal lagoons exposed to the annual fluctuating hydrological regime with flooding and desiccation periods. Rhabdoderma lineare y Porphyridium purpureum are new records for Peruvian flora. [ABSTRACT FROM AUTHOR]

This research explores the Messinian record in a western Mediterranean basin at the eastern end of the Betic Cordillera (the Garruchal section, southern sector of the Bajo Segura basin). Sedimentary facies development and foraminiferal assemblages were used as palaeoenvironmental proxies to characterize the palaeoceanographic evolution of the basin's progressive restriction. Therefore, a succession of palaeoenvironmental phases can be established as follows. The "start phase" (until ~ 6.72 Ma) records the first ecological evidence of the restriction, evidenced by the sudden appearance of common benthic stress markers. The "amplification phase" of the restriction (up to ~ 6.35 Ma) marks a progressive increase in low bottom oxygen levels related to water-mass stratification in the evolution from upper epibathyal to outer shelf environments. The "consolidation phase" (until the intra-Messinian discontinuity ~ shortly after 6.03 Ma) records basin shallowing (from outer to inner shelf environments) in a context of a restricted basin. And lastly, the "climax phase" (until the end-Messinian discontinuity) records coastal sedimentation (marine coastal lagoon and sandy beaches). The findings of this research reveal that the Garruchal section is a good illustration of the sedimentary and palaeoenvironmental response of the peripheral basins to the progressive restriction of the Mediterranean before the Messinian Salinity Crisis. Finally, since it is widely accepted that the Mediterranean marine restriction has been developed in a stepwise mode, we here propose to establish the following terms for implementation at Mediterranean regional level: "start," "amplification," and "consolidation" phases, which finally led to the "climax" phase, that is, the Messinian Salinity Crisis stricto sensu. [ABSTRACT FROM AUTHOR]

This study establishes the season for the immigration (recruitment) of Penaeus setiferus and P. duorarum postlarvae into Términos Lagoon, México, as well as the hydrological conditions that occur during this event. The abundance of postlarvae of both species was used to infer the reproductive period for each species. The zooplankton collection was carried out monthly for three years. The nets used were 50 cm in diameter, 1.5 m in length and 505 µm mesh size, and temperature and salinity were measured with an YSI. The fluvial discharges were taken from Comisión Nacional del Agua (CONAGUA). The harmonic pattern variation (HPV) was analyzed for each variable (density of postlarvae, salinity, temperature and fluvial discharge). A cycle was analyzed and divided into two episodes (rise and descent) to estimate the HPV of each postlarval species. The entrance of both postlarval species starts from June to September, with higher density in August, which decreases from October to May, with the lowest density in March. The first episode was established from June to August and the second episode in September. During the first episode the hydrological conditions were: high salinity (34), a warm temperature (30°C) and low accumulated fluvial discharge (2,828 m³ s-1), while, in the second, they were low salinity (28), a moderately warm temperature (29°C) and high accumulated fluvial discharge (3,934 m³ s-1). [ABSTRACT FROM AUTHOR]

The arsenic (As) contents of sediment cores from the Patos Lagoon in southern Brazil were measured to better understand the biogeochemical cycling of As in the estuary. Sediment cores (ca. 60 cm) were obtained from three locations within the estuary to capture possible changes in As content across the salinity gradient (i.e., where saline, brackish, and freshwater dominated). Two sediment cores were collected at each location, one beneath open water and the other from the fringing salt marsh. Along with As, we quantified the particle size; redox potential (Eh); manganese (Mn), iron (Fe), total organic carbon (TOC), and free (dissolved) sulfide concentrations; and acid volatile sulfide (AVS) and chromium reducible sulfide (CRS) contents. Bioturbation supports oxygen penetration to depths between 20 and 30 cm below the salt marsh surface, where an As- and Fe-rich zone was identified (3-fold higher As than mean As contents of the sediments). A similar subsurface peak of As, Fe, and Mn occurs in the open-water cores, albeit at greater depths between 40 and 50 cm below the surface. The subsurface peak has As concentrations that are 2-fold higher than the average for each core. Vertical profiles of Eh, free sulfides, and CRS for the shallow open-water cores showed similar distribution at depths of 50 cm, suggesting that pyrite formation is an important sink for As in the open-water cores. The data demonstrate clear differences in the geochemical conditions for salt marshes and shallow open waters that can have important implications for As distribution in estuarine sediments. [ABSTRACT FROM AUTHOR]

Chilika Lagoon is divided in to four geographical sectors depending on the flora, fauna and water quality parameters. The water quality is described on its physical, chemical and biological characteristics. Physico-chemical parameters like temperature, depth, transparency, salinity, dissolved oxygen and pH of water samples collected from four different sectors of Chilika Lagoon were documented for two years. From overall analysis, it was observed that there was a lot of fluctuation in the physico chemical parameters of water which were under permissible limit and fluctuated widely according to seasons and sectors. [ABSTRACT FROM AUTHOR]

In April 2014, Ukraine has stopped the supply of Dnieper river water in the North Crimean Canal, bringing began to a salinity increase in the Gulf of Sivash (the Sea of Azov). Expeditions, which were conducted on Sivash in 2013-2015, have made it possible to evaluate the occurred changes in salinity, the concentration of total suspended solids (TSS), dissolved organic matter, as well as in macro- and meiobenthos, and plankton. Particular attention was paid Harpacticoida taxocene. In the 2014-2015, salinity was 40-70 g/L, it is significantly higher than in previous years (average 22 g/L). In 2014-2015, the concentration of TSS was three times higher than in 2013. Significant changes have occurred in benthos and plankton. Floating mats of green filamentous algae have developed intensively along coast, which noted the high number of meiobenthic Harpacticoida. In 2014-2015, species composition of Harpacticoida taxocene in the Sivash was differed from that in 2013; all of the marked species (8) were observed only in the plankton, there were only 2 species in mats, and 3 – on soft bottom. The authors conclude that the Sivash ecosystem moves into a new state

• Good response of the Lagrangian layer models to small lagoons. • A prediction of the water fluxes in the studied lagoons was obtained. • Lagoons presented higher evaporation ratios with higher Surface/Volume ratios. • Differences in water circulations caused different salinities in summer. • High-salinity water from the aquifer returned to the lagoons during autumn cyclonic storm events. Coastal wetlands are among the most productive and fluctuating ecosystems of the world. These ecosystems, however, are affected by human activities that may change their nutrient dynamics and water regime, causing the degradation of water quality, the disappearance of lagoons and wetlands, or the establishment of invasive species. In this context, the La Pletera salt marsh is composed of several coastal lagoons and wetlands that were affected by the incomplete construction of an urban development in 1987. This area has been the focus of two LIFE restoration projects aimed at recovering its ecological functionality, and protecting a threatened endemic fish species (Aphanius iberus). Thanks to these projects, a new lagoon was created in 2002 simply by excavating below sea level, which ensured water permanency all year round. Between 2014 and 2017, samples were regularly taken to measure temperature, salinity and water levels in the lagoons of the La Pletera salt marsh. In this study we focus on two natural lagoons (Life A and Life B), and the one created in 2002 (Life C). Using the one-dimensional General Lake Model (GLM), we evaluated water inflows and outflows and evaporation fluxes, since water circulation determines the resultant salinity in these lagoons. This model is an open source model that, to our knowledge, is being used for the first time in such small lagoons. The study focuses mainly on dry periods, when the lagoon inflow is low and evaporation is high. Results show that Life A and Life B are more affected by evaporation and that lagoon water circulation was higher in Life-C. From a management point of view, the maintenance of salinity conditions is fundamental for the protection of Aphanius iberus , a species adapted to high salinity fluctuations but strongly affected by competition from the invasive Eastern mosquitofish (Gambusia holbrooki) when water salinity is not high enough or variable. Between 2014 and 2018, additional lagoons were created in the La Pletera salt marsh as part of a new LIFE project. Knowledge of the hydrology and the resultant water salinity in the new lagoons are essential to ensure the continued survival of Aphanius iberus in the area. [ABSTRACT FROM AUTHOR]

• We studied seagrass responses to water and sediment variability in a coastal lagoon. • Both studied species were found along the environmental gradients in the lagoon. • H. wrightii focused phenotypic responses at the meadow/shoot and biochemical level. • R. maritima focused phenotypic responses at the biochemical level. • The study provides baseline data for monitoring these seagrass meadows. As seagrasses decline worldwide, determining their phenotypic variability in response to human altered environmental factors becomes important to better understand their acclimation strategies. Many studies have reported seagrass responses to environmental gradients of single parameters, using either single or multiple metrics. However, studies of species' phenotypic variations along environmental gradients that include several environmental factors are rather scarce. In this study, we evaluated and compared the responses of Halodule wrightii and Ruppia maritima at different organizational levels (meadow/shoot, leaf and biochemical level) to key environmental factors, such as urbanization, light availability, salinity and sediment characteristics in a subtropical Brazilian coastal lagoon. Both species tolerated the variable environmental conditions across the lagoon, but showed species-specific differences in the adjustments at certain organizational levels. Halodule wrightii , an opportunistic species, expressed phenotypic responses mostly at the meadows/shoot and biochemical level, while the colonizer R. maritima exhibited phenotypic variability mostly constrained to the biochemical level. Also, determinations on a few selected meadows showed species-specific photosynthetic responses to environmental conditions. These differences might be related to the species' life history, with R. maritima performing adjustments at organizational levels with a fast response time, while the longer life span of H. wrightii makes also investments in modifications at the shoot and meadow level useful. Thus, this study demonstrates differences in seagrass acclimation strategies in response to environmental variability and, as a first study in this region, it also provides useful baseline data that will allow detecting potential changes and/or deterioration of the habitat. [ABSTRACT FROM AUTHOR]

Foraminiferal propagule banks occur in fine sediment fractions that contain small individuals of benthic foraminifera. These sediments include locally sourced juveniles and propagules, as well as allochthonous propagules that have dispersed from surrounding areas. Such propagules can remain viable even under unfavorable local conditions. When exposed to more favorable conditions, they may grow to adult stages. Accordingly, during environmental changes, propagule banks have the potential to function as species pools and allow quick assemblage reactions. The propagule method was designed to study responses of foraminiferal assemblages by exposing propagule banks to controlled conditions in the laboratory, an approach that is applicable to a variety of ecological questions. Therefore it is important to understand the nature and dynamics of propagule banks, including local and seasonal influences. To obtain insights into the composition of local propagule banks, we studied experimentally grown assemblages from two shallow-water lagoons on Corfu Island in western Greece, and compared the results with in situ assemblages. We sampled in spring and autumn of 2017 and experimental treatments included the use of different substrates in our experiments to account for potential effects on assemblage compositions. Results revealed that sediments from each lagoon contained a distinct propagule bank. We found abundant allochthonous taxa among specimens grown in all experimental treatments, indicating dispersal of propagules, and possibly also juveniles, from adjacent regions into both lagoons. The time of sampling had a significant effect on experimental assemblages, indicating that the composition of propagule banks can vary throughout the year. However, no significant differences were found in assemblages grown in different substrata, suggesting a stronger influence of water variables (e.g., temperature or salinity) on assemblage compositions. Moreover, the experimental set-ups favored small, fast-growing, sediment-dwelling species tolerant of relatively high organic content. Our findings highlight the potential of propagule banks as species pools and will help to refine and improve future applications of the method. [ABSTRACT FROM AUTHOR]

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

Summary: Sivash Bay is the largest hypersaline lagoon in the world. In 1963-1975 the North Crimean Canal was constructed, with water from the River Dnieper and discharge of drainage water collected from agricultural lands into Sivash Bay. Salinity in Sivash Bay began to drop, resulting in a new brackish water ecosystem. The political decision to stop supplying water from the River Dnieper to the Canal was made in 2014, and the discharge of fresh water into the lagoon ended, resulting in an increase in salinity up to 60-75 g l−1. This study showed that the abundance of meiobenthos increased, with Nematoda dominating. The composition of nematode species in the lagoon has not previously been studied. Using samples from 1979, 2013 and 2015, 50 nematode species and forms were identified in 1979, 32 in 2013 and 21 in 2015. The species composition of nematodes at different periods was significantly different. The average abundance of nematodes was 134 198 ind. m−2 in 2013 and 606 660 ind. m−2 in 2015. [ABSTRACT FROM AUTHOR]

The effects of salinity and temperature on the photosynthetic and growth performance of the seagrasses Cymodocea nodosa and Ruppia cirrhosa were studied to understand their local seasonality and distribution. Cymodocea nodosa shoots were collected from Cape Vrasidas, and R. cirrhosa shoots from the coastal lagoon Fanari, all from the Eastern Macedonian and Thrace Region, Greece. Effective quantum yield (ΔF/Fm′), leaf chlorophyll-a content (mg g−1 wet mass) and growth (% of maximum) were tested at different temperatures (10–40°C) and salinities (5–60). The results showed that: (a) R. cirrhosa was more euryhaline (5–55/60) than C. nodosa (10–50), (b) the upper thermal tolerance of C. nodosa (34–35°C) was higher than that of R. cirrhosa (32–34°C), (c) C. nodosa could not tolerate 10°C, whereas R. cirrhosa could, and (d) the growth optimum of C. nodosa was 30°C and that of R. cirrhosa 20–30°C. The thermal optima and tolerances of growth and photosynthesis confirm the seasonal patterns of R. cirrhosa but not of C. nodosa. However, the sensitivity of C. nodosa to low salinities and temperatures may explain its absence from shallow coastal lagoons. Ruppia cirrhosa could be vulnerable to future climate change. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyze water circulation in an estuary located in Boca del Río, Veracruz, Mexico. The diagnosis is based on the most representative flux records for the Jamapa River during the dry and rain seasons, that is, April and September, respectively. Tidal conditions, temperature, and water density were taken into account. For the diagnosis, a three-dimensional model (Delft3D) was applied. The seasonal circulation governing the estuary was evaluated using barotropic and baroclinic pressure levels. During the dry season, estuarine circulation was governed by the tides, and water circulation in the Mandinga lagoons was induced by baroclinic conditions. During the rainy season, the estuarine system was governed by discharge from the Jamapa River, and water circulation in the Mandinga lagoons is influenced by barotropic gradients. [ABSTRACT FROM AUTHOR]

This study compares living (LA) and dead (DA) benthic foraminiferal assemblages and identifies different factors that possibly cause differences in the distribution of both assemblages in the Aveiro Continental Shelf (Portugal). A total of 44 sediment samples was collected during summers of 1994 and 1995 along transects (east-west direction) and between 10 and 200 m water depth. Complex statistical analyses allow us to compare the abundance and composition of the LAs and DAs in function of depth, grain-size and total organic matter in all studied stations even in those where the numbers of individuals were rare in one or both assemblages. The highest densities and diversities of the LAs are found in the middle continental shelf on gravel deposits (coarse and very coarse sands) mostly due to the substrate stability, reduced deposition of fine sedimentary particles, availability of organic matter with high quality related to oceanic primary productivity likely induced by upwelling events, and oxygenated porewaters conditions. The DAs have, in general, higher densities and diversities than the LAs. In the outer continental shelf, the dissimilarity between both assemblages is higher due to the accumulation of tests, low dilution by sedimentary particles and scarcity of living foraminifera. Based on the comparison of LAs and DAs and considering the characteristics of the study area and the species ecology, it has been possible to understand the cause of temporal deviation between the LAs and DAs of benthic foraminifera. This deviation is much more pronounced in the inner shelf where the energy of the waves and the currents induce very dynamic sedimentary processes preventing the development of large LAs and the preservation of DAs. Some deviation also occurs in the middle shelf due to the seasonal loss of empty tests. The most well-preserved time-averaged DAs were found in the outer continental shelf. [ABSTRACT FROM AUTHOR]

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

Since 2001, water main drainage of sugarcane farms located in the east side of Karoon River has been deviated to Shadegan lagoon. The average discharge and salinity of the drain water in spring and summer were 20 and 20.5 m3 sec-1 and 17.1 and 13.3 dS m-1, respectively. Therefore, there have been considerable changes in the lagoon water quality when compared to the time before entering the drain water. Therefore, an experiment was performed to investigate the effects of sugarcane waste water on the quality of Lagoon’s water. The results showed that the average salinity was increased significantly before and after the entrance of the drainage into different points. The average salinity in the sample point No.2 (along the entrance of the drainage) in summer was changed from 17.7 to 51.5 dS m-1. The results, therefore, revealed that after the entrance of drainage water to Lagoon, during summer time, water salinity and mineral concentrations were increased for all locations except the points of 1 (on the northern margin of Lagoon) and 3 (influenced by Jarahi River). Phosphate ion concentration was increased at all investigated locations, but the highest phosphate concentrations were observed at the location points of 1 and 2 in summer. Given the important role of this lagoon in the protection of animal and plant spices, it is essentially important for sugarcane production companies to adopt a special measure for the protection of Lagoon from any source of pollution. [ABSTRACT FROM AUTHOR]