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Brackish water ecosystems often have high primary production, intermediate salinities, and fluctuating physical conditions and therefore provide challenging environments for many of their inhabitants. This is especially true of the Baltic Sea, which is a large body of brackish water under strong anthropogenic influence. One freshwater species that is able to cope under these conditions in the northern Baltic Sea is the vendace (Coregonus albula), a small salmonid fish. Here, we review the current knowledge of its ecology and fishery in this brackish water environment. The literature shows that, by competing for resources with other planktivores and being an important prey for a range of larger species, C. albula plays a notable role in the northern Baltic Sea ecosystem. It also sustains significant fisheries in the coastal waters of Sweden and Finland. We identify the need to better understand these C. albula populations in terms of the predator–prey interactions, distributions of anadromous and sea spawning populations and other putative (eco)morphs, extent of gene exchange between the populations, and effects of climate change on their future. In this regard, we recommend strengthening C. albula‐related research and management efforts by improved collaboration and coordination between research institutions, other governmental agencies, and fishers, as well as by harmonization of fishery policies across national borders. [ABSTRACT FROM AUTHOR]

Breeding program in order to increase genetic improvement in blue tilapia have not been widely carried out at brackish water ponds. This study aimed to evaluate the increase in growth and genetic gain of F-4 blue tilapia from family selection in ponds with 25-30 gL-1 salinity. The parent used for the formation of F-4 is the selected parent F-3 and as a control using the non-selected parent F-3. Spawning was carried out in a full-sib mating design using the family selection method. The ratio of male and female broodstock is 1: 2. Spawning and nursery activities of F-4 blue tilapia are carried out in freshwater. The enlargement test was carried out in the net cage 5m x2.5m x1 m which was installed in the ponds with a salinity of 25-35 g l-1 for 120 days, at a stocking density of 10 fish m-2. At the end of maintenance, a selection process is carried out on the weight traits. Parameters observed included growth, survival, and genetic values. The results showed that the growth and survival in the F-4 blue tilapia population, male and female selected populations, had a higher value than in the non-selected population. The realized heritability value of the population growth character of the F-4 blue fish is in the high category. The difference in the average weight of the selected blue tilapia and the control was equivalent to an increase in genetic value added by 15.06% (male population) and 17.92% (female population). [ABSTRACT FROM AUTHOR]

Copyright of Revue de Micropaleontologie is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This hydrochemical study of the surface and groundwater in Khan AL-Baghdadi area, western Iraq, included the interpretation of physical, chemical, and biological properties. Water samples were collected from wells (14 samples) and surface water of Euphrates River (6 samples) for the dry and wet periods of October 2018 and April 2019, respectively. The stable isotopes analysis was performed for the dry period only. The surface water samples were characterized by slightly alkaline, fresh, excessively mineralized, Ca-chloride type, and hard to very hard water class. While the groundwater samples were characterized by slightly alkaline, brackish, excessively mineralized, Ca-chloride and Na-Chloride type, and hard to very hard water class. The stable isotopic analysis was used in studying the interaction between water resources of Euphrates River and groundwater. Stable isotopes (δD and δ18O) were used to study the hydrological aspects of water resources in the study area. The results showed that surface and groundwater samples have similar source with a correlation relationship between them, in addition to the clear effect of river recharge on groundwater. The variation in δ2H and δ18O signature of groundwater in the study area is caused mainly by variation in isotopic composition of recharge water zone and mixing water. Using the δ 2H and δ 18O diagram, all surface and groundwater samples were plotted below the global meteoric water line (GMWL) and Local Meteoric Water line (LMWL), indicating the influences of the evaporation processes and seasonal variation. [ABSTRACT FROM AUTHOR]

Highlights • We evaluated C dynamics in a created marsh having salinity of 10–30 psu. • The marsh was a net C sink and fixed 1.85 g C m−2 day−1 by plants. • 41–46% of the fixed C remained in plants while 8.6–13.2% was transformed to soil. • CO 2 credit of $30.76–$47.90 USD per hectare was realized from this project. Abstract Carbon (C) sequestration through accumulated plant biomass and storage in soils can potentially make wetland ecosystems net C sinks. Here, we collected GHG flux, plant biomass, and litter decomposition data from three distinct vegetation zones (Spartina alterniflora , Juncus roemerianus and Spartina patens) on a 7-year-old created brackish marsh in North Carolina, USA, and integrate these data into an overall C mass balance budget. The marsh fixed an average of 1.85 g C m−2 day−1 through plant photosynthesis. About 41–46% of the fixed C remained in plants, while 18.4% of the C was decomposed and released back to the atmosphere as CO 2 and CH 4 , and 8.6–13.2% of the decomposed C was stored as soil C. In all, this created marsh sequestered 28.7–44.7 Mg CO 2 year−1 across the 14 ha marsh. Because the brackish marsh emitted only small amounts of CH 4 and N 2 O, the CO 2 equivalent emission of the marsh was −0.87 to −0.56 g CO 2-eq m−2 day−1, indicating the marsh has a net effect in reducing GHGs to the atmosphere and contributes to cooling. However, resultant CO 2 credit (through the increment of soil C) would be worth only $30.76–$47.90 USD per hectare annually, or $431–$671 per year for the project, which, coupled with other enhanced ecosystem services, could provide landowners with some additional economic incentive for future creation projects. Nevertheless, C mass balance determinations and radiative cooling metrics showed promise in demonstrating the potential of a young created brackish marsh to act as a net carbon sink. [ABSTRACT FROM AUTHOR]

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

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

Saemangeum Reservoir in South Korea is an estuarine system enclosed by a dyke construction, where seawater inflow and retained water outflow are managed by the opening/closing of sluice gates installed in the southern part of the dyke. An exchange of the reservoir water can cause spatiotemporal fluctuations in the salinity and trophic state, which are major drivers determining variation in the composition of biological communities in estuarine systems. Here, we investigated the seasonal and spatial variability in the copepod community and environmental conditions (water temperature, salinity, transparency, chlorophyll a concentration, total nitrogen, total phosphorus and Carlson’s trophic state index) based on seasonally conducted field monitoring in the Saemangeum Reservoir from July 2013 to January 2018. In addition to the role of temperature, salinity and chlorophyll a concentration in structuring the copepod community and diversity, the biological indices of copepods with respect to salinity range and trophic state, were evaluated. The spatiotemporal variability in the salinity and trophic state variables showed contrasting patterns, and chlorophyll a concentration was negatively affected by salinity, indicating that the reservoir water was being highly exchanged with opening of the sluice gates. The mean trophic state index values, however, were constant in the eutrophic state (50―70). Dominant copepods were Acartia (A. hudsonica, A. sinjiensis, Acartia spp.) and Oithona (O. davisae and Oithona spp.), which are common species in eutrophic neritic water. Variation in the copepod community was mainly associated with the seasonal succession of the dominant species rather than a spatial gradient (from around the estuary to the sluice gates); however, site-specific differences in frequencies of several non-dominant species could be detected around the estuary (Sinocalanus tenellus) and the sluice gates (Centropages spp., Tigriopus spp. and Labidocera rotunda). The copepod diversity increased with species-richness from around the estuary to the sluice gates, which could result from variation in the site-specific location of non-dominant species. The frequency of particular species was also able to discriminate in terms of the salinity range (oligohaline: A. pacifica, S. tenellus and A. sinjiensis; mesohaline: Pseudodiaptomus inopinus; and polyhaline: C. abdominalis and Centropages spp.) and the trophic state (mesotrophic: C. abdominalis, Calanus sinicus and Centropages spp.; and hypereutrophic: S. tenellus, P. inopinus and Sinocalanus spp.). The findings from this study not only identify the factors determining spatiotemporal variation in the copepod community in the Saemangeum Reservoir, but also expand the applicability of copepods as biological indicators of conditions associated with salinity range and trophic state in other enclosed estuarine systems. [ABSTRACT FROM AUTHOR]

In response to shoreline erosion and potentially more severe storm damage due to climate change and sea level rise, armouring of shorelines using traditional hard structures is likely to increase. An emerging alternative to seawalls and other hard structures is to create 'living shorelines' where natural habitats are incorporated into a resilient shoreline stabilization design. Research has shown that functional, multiuse living shorelines provide options for reducing erosion rates and sustaining shoreline stability while supporting intertidal and nearshore habitat. Drawing upon the scientific literature, shoreline management best practices, and the results from an expert opinion survey, we propose a spatial decision framework for multiclass suitability analysis of generic shoreline stabilization options with a focus on the unique challenges and opportunities of South Florida. The results have been incorporated into a web application that can facilitate decision-making in support of nature-based stabilization infrastructure. [ABSTRACT FROM AUTHOR]

Nitrite is a well-known toxicant in aquaculture, produced as intermediate in nitrification. Two nitrite-oxidizing bacterial consortia, one from marine environment and the other from brackish water, were developed by enrichment technique at National Centre for Aquatic Animal Health, for removal of nitrite from recirculating aquaculture systems. In the present study, bacterial diversity of the consortia was assessed based on 16S ribosomal RNA and the functional gene analysis. Clone libraries of 16S ribosomal RNA gene and nitrite oxidoreductase A gene were constructed, and amplified ribosomal DNA restriction analysis was carried out to cluster the clones. Dendrograms generated through molecular characterization showed 29 and 27 clusters in marine and brackish water consortia, respectively. Phylogenetic analyses of representative clones from each cluster depicted profound diversity in the consortia consisting autotrophic nitrifiers belonging to Proteobacteria, anaerobic ammonia oxidizers, Actinobacteria, Bacteroidetes and heterotrophic denitrifiers. Functional gene analysis corroborated with the presence of specific nitrite oxidizers. Quantitative polymerase chain reaction showed the abundance of nitrite oxidizers in the order of 1.51 ± 0.38 × 109/g and 4.88 ± 0.42 × 107/g in marine and brackish water consortia, respectively. Diversity indices and pattern of distribution of organisms within the consortia were analyzed using Geneious, VITCOMIC, Mega 5 and Primer software. The marine nitrite-oxidizing consortium showed higher Shannon-Wiener diversity and mean population diversity than brackish water consortium, suggesting that the former was having more diverse flora and higher potential to be used as startup cultures for activating nitrifying bioreactors subsequent to acclimatization to the required salinity. [ABSTRACT FROM AUTHOR]

The major part of the north polar region is intensely rising by postglacial crustal movement. This process gives rise to the separation of different basins from seas and oceans, which affects a combination of freshwater and marine organisms. Gradually losing contact with the seas, many near-shore lakes of the Arctic are mostly desalted and form bogs. Fungi as decomposers play an important role in all ecosystems. However, the diversity and role of fungi in Arctic aquatic ecosystems is largely unknown. It is also not clear how the taxonomic structure of the fungal community is affected by the process of gradual desalinization and waterlogging. We investigated the diversity of filamentous culturable fungi in different parts of the brackish Kislo-Sladkoe Lake (White Sea, Russia). Annually, 42 samples of the bottom and coastal soils have been collected at the lake from which fungi were recovered on standard and selective media. Based on morphological and molecular markers, a total of 127 taxa have been identified. The fungal community appeared to be influenced by its sea origin and comprised both marine (Paradendryphiella salina, Acremonium spp.) and terrestrial soil species of Penicillium, Talaromyces, Mucor, Umbelopsis, Cladosporium, Cadophora, Sistotrema, Helotiales, Pleosporales, sphagnum moss destructors (Oidiodendron spp.) and insect-associated species of Tolypocladium. The results indicate that the composition of the fungal community in the rising polar White Sea region reflects the dynamics of global changes in physical-chemical parameters and animal and plant associations because of separation from the sea. [ABSTRACT FROM AUTHOR]

The shells of some freshwater and brackish-water gastropods, including species of Pleuroceridae, Vivipalidae, and Neritidae, show considerable deterioration while their inhabitants are still alive and reproductively active, giving them the appearance of dead or empty shells. Although the worn-out appearance of these shells may be an inevitable outcome of their tendency to dissolve in calcium-poor water, it is possible that the gastropods adjust their investment in shell calcification to allow for moderate shell corrosion. The habitats where gastropods live retain many old, empty shells, and, by mimicking these disused shelters in appearance and texture, gastropods with corroded shells may avoid detection by predators using visual and tactile cues to locate prey. A similar behaviour, whereby animals use niche construction by conspecific antecedents to masquerade as old deserted dwellings, may also be found in other animal groups, such as leaf-rolling caterpillars, leaf beetles and land snails on limestone habitats. [ABSTRACT FROM AUTHOR]

This case study examines the livelihood of small-scale fish farmers in the state of Kedah, Malaysia, with emphasis on their asset possession, livelihood strategies performed and livelihood outcomes achieved. The relationship between these livelihood elements was also analyzed in order to identify the triggering factors contributing to their sustainable livelihood. Data were obtained through systematic socio economic survey of 216 smallscale freshwater and brackish-water pond fish farmers using stratified random sampling. The Structural Equation Modelling method was applied to analyze the relationship between the three elements of the fish farmers' livelihood. The results show that there are significant differences between freshwater and brackish-water systems, particularly in terms of profitability and contribution to the livelihood of farmers due to their involvement level in the activity. Human and financial assets are important components in the livelihood of small-scale fish farmers based on their positive influence on the level of Good Aquaculture Practices, species cultured, total household income and social impact variables. Thus, measures related to the enhancement of farmer's knowledge and their financial status should be emphasized in order to improve the livelihood of small-scale fish farmers in Malaysia. [ABSTRACT FROM AUTHOR]

Estuaries, coastal lagoons and other transition ecosystems tend to become the ultimate reservoirs of pollutants transported by continental runoff, among which pesticides constitute the class of most concern. High amounts of dissolved and particulated organic matter greatly contribute to the accumulation of pesticides that eventually become trapped in sediments or find their way along food chains. Perhaps not so surprisingly, it is common to find elevated levels of pesticides in estuarine sediments decades after their embargo. Still, it remains challenging to address ecotoxicity in circumstances that invariably imply mixtures of contaminants and multiple factors affecting bioavailability. Despite advances in methods for detecting pesticides in waters, sediments and organisms, chemical data alone are insufficient to predict risk. Many researchers have been opting for ex situ bioassays that mimic the concentrations of pesticides in estuarine waters and sediments using a range of ecologically relevant model organisms, with emphasis on fish, molluscs and crustaceans. These experimental procedures unravelled novel risk factors and important insights on toxicological mechanisms, albeit with some prejudice of ecological relevance. On the other hand, in situ bioassays, translocation experiments and passive biomonitoring strive to spot causality through an intricate mesh of confounding factors and cocktails of pollutants. Seemingly, the most informative works are integrative approaches that combine different assessment strategies, multiple endpoints and advanced computational and geographical models to determine risk. State-of-art System Biology approaches combining high-content screening approaches involving “omics” and bioinformatics, can assist discovering and predicting novel Adverse Outcome Pathways that better reflect the cumulative risk of persisting and emerging pesticides among the wide range of stressors that affect estuaries. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the brackish ecosystem of the Gulf of Riga, the calanoid copepod Eurytemora affinis is a key species, but recently a new non-indigenous species Eurytemora carolleeae was discovered in the region. In the present study, we aimed to validate the presence of E. carolleeae in the southern part of the Gulf of Riga five years after its first discovery. The study area is the closest region to the Rīga harbour — the main source of non-indigenous species arrival in the Gulf. Recent studies have predicted the possible potential of E. carolleeae invasion due to its physiological plasticity. Male and female specimens of Eurytemora were collected in spring, summer, and autumn of 2013, and analysed based on three morphological indicators. Despite the higher reproduction rate of E. carolleeae, this intrusive species does not seem to have succeeded in establishing during the five-year period after its first discovery in the Gulf of Riga, and hence does not present a threat to the native E. affinis population in the study area. [ABSTRACT FROM AUTHOR]

Objectives: Report the exploratory study results of the performance of a conventional solar still prototype using seawater and brackish water (river and well) at three locations in northern Chile at different geographical heights. Materials and methods: A solar still with an effective distillation area of 0.54 é was used. Three tests were performed with seawater, 1 with river water and 1 with well water. The temperatures and environmental parameters were measured every 10 minutes for 36 continuous hours. The efficiency was evaluated in terms of seawater and the capacity to remove natural contaminants from brackish water. Results and discussion: The productivity in the three selected areas was 3 and 4 L/é for seawater and brackish water, respectively. The removal of boron and arsenic complies with the regulations of the country. Conclusion: The results obtained are of exploratory character for the zones, where the geographic height and the total dissolved solids are factors that determine the performance of a passive solar still, which is higher when water is used with low concentrations of solids. [ABSTRACT FROM AUTHOR]

The Mississippi coastal region has two major rivers and four smaller rivers influencing the estuaries that make up the Mississippi Sound. The islands off Mississippi create a barrier which allows the area to be a widespread, productive estuarine region. With such a dependence on discharge from the drainages, it is important to understand the effect of salinity regimes on fish communities. Drought conditions in other regions have been shown to dramatically change the fish community structure. We used the long running Interjurisdictional Fisheries Program database (2006-2014) within Mississippi state waters and compared yearly fish communities between drought and non-drought years. Non-metric Multidimensional Scaling (nMDS), Analysis of Similarity (ANOSIM), and Indicator Species Analysis (ISA) were used to compare drought and non-drought conditions in the Mississippi Sound. During 2006 and 2007, which were identified as drought years by the Palmer Drought Severity Index (PDSI), differences in fish community structure were identified and compared to non-drought years (2008-2009 and 2011-2014). The ISA identified a total of eight species that were significantly influenced by drought years. Of the eight species, the abundance of seven species significantly decreased while the abundance of one species significantly increased. With an increasing human population in central and south Mississippi, pressure on freshwater resources is likely to increase, resulting in possible changes in the fish community dynamics of the Mississippi Sound. Understanding the influence of decreased river discharges will assist managers in determining the impacts of freshwater withdrawals during base flow periods. [ABSTRACT FROM AUTHOR]

Bioavailable dissolved organic carbon (B DOC ), nitrogen (B DON ) and their degradation rate constants were measured for the Chilika Lagoon, India. Long-term laboratory incubation experiments (90 days) were conducted at a constant temperature (25 °C) to quantify the bioavailable dissolved organic matter (DOM) and the possible degradation rate coefficients. The results showed that 41 ± 12% of dissolved organic carbon (DOC) and 47 ± 17% of dissolved organic nitrogen (DON) were B DOC and B DON respectively, with their stoichiometry found to be higher than the Redfield ratio. A first order exponential non-linear fitting routine was used to estimate pool sizes. The degradation rate constant (k) for the B DOC varied from 0.127–0.329 d −1 and B DON from 0.043–0.306 d −1 during the study period. Half-lives of the B DOC and B DON ranged from 2.1–5.4 and 2.2–15.9 days, respectively. Overall, the results showed that a fraction of the labile DON was transported from the lagoon to the adjacent coastal sea. [ABSTRACT FROM AUTHOR]

Literature data, museum collections as well as fieldwork were used to produce an up-to-date distribution map and a list of records of Sympetrum tibiale, a species restricted to the semi-deserts of Russia, Kazakhstan, Uzbekistan, Mongolia and western China. The type locality is in Xinjiang province, China, and the type specimens are preserved in the Zoological Museum of Hamburg, Germany (ZMUH). Language barriers, publication in obscure journals and poor data exchange meant S. tibiale was little-known to non-Russian speaking odonatologists for a long time. Yet, it has been confirmed to breed in the steppes of the Kuma-Manych Depression on the western shore of the Caspian Sea, situated in the southern part of European Russia, making the species a genuine member of the European fauna. This article addresses these European sites, hitherto neglected in non-Russian language literature, and establishes the correct westernmost limit of the species' range. In addition, all currently certified records are mapped. Available knowledge on the species' ecology - a summer species with a larval preference for brackish water - is summarized. Identification characters of adults and larvae are provided; its closest relative is identified as Sympetrum depressiusculum. [ABSTRACT FROM AUTHOR]

Since 1996, the invasive Conrad's false mussel Mytilopsis leucophaeata (Conrad) has been recorded in brackish water bodies in the Ponto-Caspian region, which includes the basins of the Black Sea, Azov Sea, and Caspian Sea. In the Azov-Black Sea basin, where the number of records is increasing, its range currently includes the Dniester, Dnieper-Southern Bug, and Don River estuarine systems, and the mouth of the Tuapse River near the town of Tuapse. In the Caspian Sea basin, M. leucophaeata is present in areas near the mouths of the Volga and Ural rivers, and in the south Caspian Sea, near Bandar Anzali town. The present study analyses new records from this region as well as previously published records. All sites in the Azov-Black Sea basin with records of living specimens of M. leucophaeata were characterized by changes in the hydrological regime due to the effect of hydraulic engineering (mostly along deep-water shipping canals or for fish ladders). The most probable vector for long-distance dispersal of M. leucophaeata is transatlantic shipping to the Black Sea basin; while for secondary spread, coastal and inland shipping across adjacent ports is likely. Introduction of this species to the Caspian Sea could have resulted from specimens first present in the Black Sea or from independent long-distance transfer. [ABSTRACT FROM AUTHOR]

Excretion of nutrients by zooplankton is a complex process crucial for the functioning of aquatic ecosystems. Most of the available literature data concern excretion in freshwater or marine ecosystems, but little is known about the nutrients regeneration in brackish water bodies, and the described research results are often inconclusive. Therefore, the aim of this study was to investigate the intravital release of nitrogen and phosphorous in brackish water bodies and to analyze the effect of salinity levels on the process of excretion. Studies on excretion were based on laboratory experiments. In 2010, the rate of intravital release of nutrients by zooplankton sampled from the natural environment of the Vistula Lagoon and Lake Łebsko was analyzed in order to estimate the rate of excretion of nitrogen and phosphorus depending on the salinity level. A similar experiment was also carried out on monocultures of Brachionus calyciflorus. Results from studies on natural populations revealed variable rates of nutrients excretion for different levels of salinity. This correlation, however, was not statistically significant. Experiments on B. calyciflorus monocultures showed a significant (p < 0.05) linear correlation between salinity and excretion. The study demonstrated that higher concentrations of salts dissolved in water accelerate the rate of nutrients regeneration by zooplankton. The investigated process is determined by many factors, and for the reliable estimation of the excretion rate a multivariate analysis should be performed. [ABSTRACT FROM AUTHOR]

The widely distributed snail species Theodoxus fluviatilis (Linneaus, 1758) is rather diverse in shell size and patterning. It has formed regional subgroups in northern Germany that appear separate in either fresh- or brackish water, yet, according to literature, are indistinguishable by morphology, anatomy or mtRNA markers. Tolerance towards challenging salinities, however, is distinct. The question as to whether the observed difference in salinity tolerance is a result of local adaptation or of phenotypic plasticity remains. In this study, physiological limits to salinity stress and tolerance shift abilities were compared between individuals from both subgroups in a salinity transfer experiment and acclimation regime followed by a survival analysis. Brackish water animals struggled in freshwater but performed much better than freshwater individuals when directly transferred into higher salinities. With acclimation to their challenging salinities, individuals of both subgroups achieved shifts in the slopes of their reaction norms and were able to survive salinity levels otherwise lethal to them. Even with this shift freshwater animals were not able reach the tolerance levels of brackish water individuals. The results indicate that phenotypic plasticity as well as genetic adaptation may determine osmotolerance in regional subgroups of T. fluviatilis. [ABSTRACT FROM AUTHOR]

Although brackish marsh has been the subject of decades of research, tidal freshwater regions are still poorly understood. To provide insight into spatial and temporal dynamics of nutrients, physical conditions, and the plankton community in freshwater tidal habitat, we investigated from 2011 to 2014 a remnant freshwater tidal slough complex located in the Sacramento-San Joaquin Delta region of the San Francisco Estuary. Our results suggest that the tidal slough complex showed different seasonal nutrient, physical, and biological conditions when compared to a relatively homogenous adjacent large river channel, the Sacramento River. The tidal slough complex also showed substantial spatial variability in habitat conditions compared to nearby main river channels. Nutrient dynamics in the tidal slough complex appear to be driven by a complex suite of factors, including inflow from upstream tributaries and tidal flows from the downstream reach of the Sacramento River. Chlorophyll a in the tidal sloughs responded more strongly to upstream flow pulses than other environmental variables. The tidal slough complex generated significantly higher levels of chlorophyll a than other freshwater regions of the Delta. The 2011 and 2012 results were especially notable because unusually large flow pulses through the tidal slough complex appear to have contributed to rare phytoplankton blooms in downstream areas of the Delta during the fall months. Moreover, the 2012 flow pulse stimulated higher trophic levels, because significantly higher levels of zooplankton were in the tidal slough complex after the flow event. These results have important implications for our understanding of the functioning of freshwater tidal habitat, and for the design of potential restoration projects in these regions. [ABSTRACT FROM AUTHOR]

Understanding the distribution and abundance of organisms can be exceedingly difficult for pelagic fish species that live in estuarine environments. This is particularly so for fish that cannot be readily marked and released or otherwise tracked, such as the diminutive delta smelt, Hypomesus transpacificus, endemic to the San Francisco Estuary. The environmental factors that influence their distribution operate at multiple scales, from daily tidal cycles and local perceptual fields to seasonal and annual changes in dominant environmental gradients spanning the entire San Francisco Estuary. To quantify scale-specific patterns and factors shaping the spatiotemporal abundance dynamics of adult delta smelt, we fit a suite of models to an extensive, spatially resolved, catch survey time series from 13 annual cohorts. The best model included cohort-specific abundance indicators and daily mortality rates, a regional spatial adjustment, and haul-specific environmental conditions. The regional adjustment identified several density hot spots that were persistent across cohorts. While this model did include local environmental conditions, the gain in explained variation was relatively slight compared to that explained by the regional adjustment. Total abundance estimates were derived by multiplying habitat volume by catch density (design-based) and modeled density (model-based), with both showing severe declines in the population over the time period studied. The design-based approaches had lower uncertainty but potentially higher bias. We discuss the implications of our results for advancing the science and improving management of delta smelt, and future data collection needs. [ABSTRACT FROM AUTHOR]

The aim of this work was to analyze the thermal responses of Odontesthes nigricans, Eleginops maclovinus and diadromous Galaxias maculatus, key species in estuarine areas of the Beagle Channel (Tierra del Fuego, Argentina), under a climate change scenario. We hypothesized that in the southernmost limit of the species’ distribution, individuals are more likely to be affected by indirect consequences of climate change rather than direct temperature mortality. Their thermal tolerance limits were assessed using the Critical Thermal Methodology and their preferred temperatures, using a thermal gradient. Additionally, the Fulton’s condition factor and the energy density of individuals were analyzed as a proxy of the condition of fishes acclimated to different temperatures. Results showed that species analyzed have the ability to acclimate to the different temperatures, intermediate to large tolerance polygons and positive relationships between preferred and acclimation temperatures, indicating their eurythermic nature. Thus, O. nigricans, E. maclovinus and diadromous G. maculatus populations from Tierra del Fuego could experience enhanced performances because of moderate warming being and, as it was hypothesized, be influenced by indirect consequences of climate change (habitat degradation or changes in trophic structure) since they are living in environments that are widely cooler than their maximum tolerance. [ABSTRACT FROM AUTHOR]

Progressive salinization of freshwater wetlands is likely to trigger significant changes in associated animal communities. Understanding how salinization affects fundamental natural history characteristics, like diet, is necessary to predict consequences of environmental change. We analyzed dietary patterns of Hyla cinerea (Green Treefrog), a generalist frog species known to inhabit freshwater and brackish wetlands. The stomach contents of coastal (e.g., brackish) and inland (e.g., freshwater) H. cinerea differed in both species variety and abundance of prey items. We also observed nematodes, a common anuran gut parasite, in inland individuals but did not observe any nematodes in coastal individuals. Our study shows differences in resource use and parasite load in H. cinerea, suggesting that wetland salinization may impact trophic dynamics and infectious disease in anuran amphibians. [ABSTRACT FROM AUTHOR]

The most suitable sturgeon species for culture in artificial systems are freshwater and non-migratory species: sterlet - Acipenser ruthenus - and Siberian sturgeon - Acipenser baerii, recently introduced in Romania. The experiment aimed at establishing the age and salinity thresholds to be taken into account in attempting to rear (Siberian sturgeon - Acipenser baerii) in a recirculating system using Black Sea water. From the point of view of adaptability in general, in about a week the individuals adapted to the captive breeding conditions of NIMRD's recirculating system. The specimens also easily adapted to manipulation during measurements, showing calm handling behavior. The food used was very easily accepted, the active feeding behavior being observed even in the presence of the staff. Throughout the experiment, the fish were active. The survival rate was 100%. However, adaptability to the brackish environment has posed problems. The experimental batch became more sedentary and ingested significantly less food compared to the control group, when salinity exceeded 3‰. Upon reaching the 7‰ threshold, all individuals were already completely refusing food, which is why it was decided to stop sea water input. The return to freshwater caused the resumption of feeding behavior in just a week, calling for further research on the osmoregulatory mechanisms of A. baerii. [ABSTRACT FROM AUTHOR]

The aim of this work was to assess the adaptive capabilities of the spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) in the open coastal waters of the Baltic Sea. The results could help to predict the likely further expansion of this species and its colonization of brackish waters. The following aspects were discussed in the paper: the occurrence of the species in the Polish coastal zone of the Baltic Sea, the plasticity demonstrated in the body size of individual crayfishes, food preferences, hemolymph osmolality and reproduction in waters of different salinities, which enable the species to colonize brackish waters. In the Vistula Lagoon (salinity 2-3 PSU), where the population of O. limosus is stable, the length of individuals ranged from 77 to 118 mm. These crayfish mostly fed on fodder; the second and the third food preferences were crayfish abdominal muscle and green algae. O. limosus is a hyper-regulator in freshwaters and at low salinities (up to 13 PSU), and a hyporegulator at higher salinities (14, 21, 28, 35 PSU). Laboratory studies showed that the embryonic development of O. limosus at salinities of 3 and 7 PSU was normal and a high level of reproductive success was achieved. Salinity of 3 PSU is more favorable for the development of juveniles than 7 PSU. It seems to be just a matter of time before this crayfish starts to form populations in the brackish, coastal waters of the Baltic Sea. [ABSTRACT FROM AUTHOR]

The present study aimed to assess whether environmental 1-nitropyrene (1-NP) concentration will induce genotoxicity and oxidative damages in tilapia, lives in estuarine and brackish water. Tilapia were exposed to waterborne 1-NP. Cellular antioxidant enzyme activity of glutathione peroxidase and oxidative damage, i.e., lipid peroxidation, protein and DNA oxidation were used as biomarkers of oxidative stress, while the micronucleus test was used for evaluation of chromosomal damage and was used as an indication of genotoxicity. Results showed that all biomarkers for oxidative stress positively responded, and micronucleus and other nuclear abnormalities frequencies significantly increased ( p < 0.001). This study showed that environmentally relevant 1-NP concentration in test water (0.15 ng/L) and in fish (3 ng/kg) induced genotoxicity and oxidative stress. Micronuclei and other nuclear abnormalities were probably formed as a result of oxidative stress. In conclusion, exposure to lower waterborne 1-NP concentration can pose a risk to freshwater and estuarine organisms through accumulation. [ABSTRACT FROM AUTHOR]

The West Coast of the United States experienced variable and sometimes highly unusual oceanographic conditions between 2012 and 2015. In particular, a warm mass of surface water known as the Pacific Warm Anomaly (popularly as “The Blob”) impinged on southern California in 2014, and warm-water conditions remained during the 2015 El Niño. We examine how this oceanographic variability affected delivery and individual characteristics of larval spotted sand bass (Paralabrax maculatofasciatus) to an estuarine nursery habitat in southern California. To quantify P. maculatofasciatus settlement patterns, three larval collectors were installed near the mouth of Mission Bay, San Diego CA, and retrieved weekly from June–October of 2012–2015. During ‘Blob‘ conditions in 2014 and 2015, lower settlement rates of spotted sand bass were associated with higher sea surface temperature and lower wind speed, chlorophyll a (chl a) and upwelling. Overall, the number of settlers per day peaked at intermediate chl a values across weeks. Individual characteristics of larvae that settled in 2014–2015 were consistent with a poor feeding environment. Although settlers were longer in length in 2014–15, fish in these years had slower larval otolith growth, a longer larval duration, and a trend towards lower condition, traits that are often associated with lower survival and recruitment. This study suggests that future settlement and recruitment of P. maculatofasciatus and other fishes with similar life histories may be adversely affected in southern California if ocean temperatures continue to rise in the face of climate change. [ABSTRACT FROM AUTHOR]

Brackish water coastal lagoons are least understood with respect to the seasonal and temporal variability in their sedimentary bacterial communities. These coastal lagoons are characterized by the steep environmental gradient and provide an excellent model system to decipher the biotic and abiotic factors that determine the bacterial community structure over time and space. Using Illumina sequencing of the 16S rRNA genes from a total of 100 bulk surface sediments, we investigated the sedimentary bacterial communities, their spatiotemporal distribution, and compared them with the rhizosphere sediment communities of a common reed; Phragmites karka and a native seagrass species; Halodule uninervis in Chilika Lagoon. Spatiotemporal patterns in bacterial communities were linked to specific biotic factors (e.g., presence and type of macrophyte) and abiotic factors (e.g., salinity) that drove the community composition. Comparative assessment of communities highlighted bacterial lineages that were responsible for segregating the sediment communities over distinct salinity regimes, seasons, locations, and presence and type of macrophytes. Several bacterial taxa were specific to one of these ecological factors suggesting that species-sorting processes drive specific biogeographical patterns in the bacterial populations. Modeling of proteobacterial lineages against salinity gradient revealed that α - and γ - Proteobacteria increased with salinity, whereas β - Proteobacteria displayed the opposite trend. The wide variety of biogeochemical functions performed by the rhizosphere microbiota of P. karka must be taken into consideration while formulating the management and conservation plan for this reed. Overall, this study provides a comprehensive understanding of the spatiotemporal dynamics and functionality of sedimentary bacterial communities and highlighted the role of biotic and abiotic factors in generating the biogeographical patterns in the bacterial communities of a tropical brackish water coastal lagoon. [ABSTRACT FROM AUTHOR]

Calanoid copepods play an important role in the functioning of marine and brackish ecosystems. Information is scarce on the behavioral toxicity of engineered nanoparticles to these abundant planktonic organisms. We assessed the effects of short-term exposure to nonfunctionalized gold nanoparticles on the swimming behavior of the widespread estuarine copepod Eurytemora affinis . By means of three-dimensional particle tracking velocimetry, we reconstructed the trajectories of males, ovigerous and non-ovigerous females. We quantified changes in their swimming activity and in the kinematics and geometrical properties of their motion, three important descriptors of the motility patterns of zooplankters. In females, exposure to gold nanoparticles in suspension (11.4 μ g L −1 ) for 30 min caused depressed activity and lower velocity and acceleration, whereas the same exposure caused minimal effects in males. This response differs clearly from the hyperactive behavior that is commonly observed in zooplankters exposed to pollutants, and from the generally lower sensitivity of female copepods to toxicants. Accumulation of gold nanoparticles on the external appendages was not observed, precluding mechanical effects. Only very few nanoparticles appeared sporadically in the inner part of the gut in some samples, either as aggregates or as isolated nanoparticles, which does not suggest systemic toxicity resulting from pronounced ingestion. Hence, the precise mechanisms underlying the behavioral toxicity observed here remain to be elucidated. These results demonstrate that gold nanoparticles can induce marked behavioral alterations at very low concentration and short exposure duration. They illustrate the applicability of swimming behavior as a suitable and sensitive endpoint for investigating the toxicity of nanomaterials present in estuarine and marine environments. Changes in swimming behavior may impair the ability of planktonic copepods to interact with their environment and with other organisms, with possible impacts on population dynamics and community structure. [ABSTRACT FROM AUTHOR]

This study reports descent of Atlantic salmon Salmo salar fry from their natal streams to brackish waters of the Baltic Sea and their use of this environment as an alternative rearing habitat before ascending back to freshwater streams. To the authors' knowledge, residency in a brackish environment has not previously been demonstrated in S. salar fry. Recruitment success and evolutionary significance of this alternative life-history strategy are presently not known. [ABSTRACT FROM AUTHOR]

Species richness in freshwater bony fishes depends on two main processes: the transition into and the diversification within freshwater habitats. In contrast to bony fishes, only few cartilaginous fishes, mostly stingrays (Myliobatoidei), were able to colonize fresh water. Respective transition processes have been mainly assessed from a physiological and morphological perspective, indicating that the freshwater lifestyle is strongly limited by the ability to perform osmoregulatory adaptations. However, the transition history and the effect of physiological constraints on the diversification in stingrays remain poorly understood. Herein, we estimated the geographic pathways of freshwater colonization and inferred the mode of habitat transitions. Further, we assessed habitat-related speciation rates in a time-calibrated phylogenetic framework to understand factors driving the transition of stingrays into and the diversification within fresh water. Using South American and Southeast Asian freshwater taxa as model organisms, we found one independent freshwater colonization event by stingrays in South America and at least three in Southeast Asia. We revealed that vicariant processes most likely caused freshwater transition during the time of major marine incursions. The habitat transition rates indicate that brackish water species switch preferably back into marine than forth into freshwater habitats. Moreover, our results showed significantly lower diversification rates in brackish water lineages, whereas freshwater and marine lineages exhibit similar rates. Thus, brackish water habitats may have functioned as evolutionary bottlenecks for the colonization of fresh water by stingrays, probably because of the higher variability of environmental conditions in brackish water. [ABSTRACT FROM AUTHOR]

The incomplete spatial coverage of CO2 partial pressure (pCO2/ measurements across estuary types represents a significant knowledge gap in current regional- and global-scale estimates of estuarine CO2 emissions. Given the limited research on CO2 dynamics in large estuaries and bay systems, as well as the sources of error in the calculation of pCO2 (carbonic acid dissociation constants, organic alkalinity), estimates of air--sea CO2 fluxes in estuaries are subject to large uncertainties. The Estuary and Gulf of St. Lawrence (EGSL) at the lower limit of the subarctic region in eastern Canada is the world's largest estuarine system, and is characterized by an exceptional richness in environmental diversity. It is among the world's most intensively studied estuaries, yet there are no published data on its surface-water pCO2 distribution. To fill this data gap, a comprehensive dataset was compiled from direct and indirect measurements of carbonate system parameters in the surface waters of the EGSL during the spring or summer of 2003-2016. The calculated surface-water pCO2 ranged from 435 to 765 μatm in the shallow partially mixed upper estuary, 139--578 μatm in the deep stratified lower estuary, and 207-478 μatm along the Laurentian Channel in the Gulf of St. Lawrence. Overall, at the time of sampling, the St. Lawrence Estuary served as a very weak source of CO2 to the atmosphere, with an area-averaged CO2 degassing flux of 0.98 to 2.02 mmol Cm-2 d-1 (0.36 to 0.74 molCm-2 yr-1/. A preliminary analysis revealed that respiration (upper estuary), photosynthesis (lower estuary), and temperature (Gulf of St. Lawrence) controlled the spatial variability in surface-water pCO2. Whereas we used the dissociation constants of Cai and Wang (1998) to calculate estuarine pCO2, formulations recommended for best practices in open ocean environments may underestimate pCO2 at low salinities, while those of Millero (2010) may result in overestimates. [ABSTRACT FROM AUTHOR]

Both effective population size and life history may influence the efficacy of purifying selection, but it remains unclear if the environment affects the accumulation of weakly deleterious nonsynonymous polymorphisms. We hypothesize that the reduced energetic cost of osmoregulation in brackish water habitat may cause relaxation of selective constraints at mitochondrial oxidative phosphorylation (OXPHOS) genes. To test this hypothesis, we analyzed 57 complete mitochondrial genomes of Pungitius pungitius collected from brackish and freshwater habitats. Based on inter- and intraspecific comparisons, we estimated that 84% and 68% of the nonsynonymous polymorphisms in the freshwater and brackish water populations, respectively, are weakly or moderately deleterious. Using in silico prediction tools (MutPred, SNAP2), we subsequently identified nonsynonymous polymorphisms with potentially harmful effect. Both prediction methods indicated that the functional effects of the fixed nonsynonymous substitutions between nine- and three-spined stickleback were weaker than for polymorphisms within species, indicating that harmful nonsynonymous polymorphisms within populations rarely become fixed between species. No significant differences in mean estimated functional effects were identified between freshwater and brackish water nine-spined stickleback to support the hypothesis that reduced osmoregulatory energy demand in the brackish water environment reduces the strength of purifying selection at OXPHOS genes. Instead, elevated frequency of nonsynonymous polymorphisms in the freshwater environment ( Pn /Ps = 0.549 vs. 0.283; Fisher's exact test p = .032) suggested that purifying selection is less efficient in small freshwater populations. This study shows the utility of in silico functional prediction tools in population genetic and evolutionary research in a nonmammalian vertebrate and demonstrates that mitochondrial energy production genes represent a promising system to characterize the demographic, life history and potential habitat-dependent effects of segregating amino acid variants. [ABSTRACT FROM AUTHOR]

Wittrockiella is a small genus of filamentous green algae that occurs in habitats with reduced or fluctuating salinities. Many aspects of the basic biology of these algae are still unknown and the phylogenetic relationships within the genus have not been fully explored. We provide a phylogeny based on three ribosomal markers (ITS, LSU, and SSU rDNA) of the genus, including broad intraspecific sampling for W. lyallii and W. salina, recommendations for the use of existing names are made, and highlight aspects of their physiology and life cycle. Molecular data indicate that there are five species of Wittrockiella. Two new species, W. australis and W. zosterae, are described, both are endophytes. Although W. lyallii and W. salina can be identified morphologically, there are no diagnostic morphological characters to distinguish between W. amphibia, W. australis, and W. zosterae. A range of low molecular weight carbohydrates were analyzed but proved to not be taxonomically informative. The distribution range of W. salina is extended to the Northern Hemisphere as this species has been found in brackish lakes in Japan. Furthermore, it is shown that there are no grounds to recognize W. salina var. kraftii, which was described as an endemic variety from a freshwater habitat on Lord Howe Island, Australia. Culture experiments indicate that W. australis has a preference for growth in lower salinities over full seawater. For W. amphibia and W. zosterae, sexual reproduction is documented, and the split of these species is possibly attributable to polyploidization. [ABSTRACT FROM AUTHOR]

This paper documents the arrival of the non-native bivalve Rangia cuneata in a shallow-water basin of Pärnu Bay, north-eastern Gulf of Riga, Baltic Sea, Estonia. The bivalve was collected for the first time in October 2016. The species occurred at low densities along a 25-km stretch of coastline. The size distribution suggests R. cuneata is established in the study area. This species represents the first obligatory suspension-feeding soft bottom bivalve in this low salinity area. Consequently, R. cuneata has a potential to intensify benthic-pelagic coupling as well as to improve the overall water quality of the bay. As Pärnu Bay is the northernmost location of the species' geographic range, winter temperature likely controls the species survival and further spread in the region. [ABSTRACT FROM AUTHOR]

Many shoreline studies rely on historical change rates determined from aerial imagery decades to over 50 years apart to predict shoreline position and determine setback distances for coastal structures. These studies may not illustrate the coastal impacts of short-duration but potentially high-impact storm events. In this study, shoreline change rates (SCRs) are quantified at five different sites ranging from marsh to sediment bank shorelines around the Albemarle-Pamlico estuarine system (APES) for a series of historical (decadal to 50-year) and short-term (bimonthly) time periods as well as for individual storm events. Long-term (historical) SCRs of approximately −0.5 ± 0.07 m year are observed, consistent with previous work along estuarine shorelines in North Carolina. Short-term SCRs are highly variable, both spatially and temporally, and ranged from 15.8 ± 7.5 to −19.3 ± 11.5 m year at one of the study sites. The influence of wave climate on the spatial and temporal variability of short-term erosion rates is investigated using meteorological observations and coupled hydrodynamic (Delft3D) and wave (SWAN) models. The models are applied to simulate hourly variability in the surface waves and water levels. The results indicate that in the fetch-limited APES, wind direction strongly influences the wave climate at the study sites. The wave height also has an influence on short-term SCRs as determined from the wave simulations for individual meteorological events, but no statistical correlation is found for wave height and SCRs over the long term. Despite the significantly higher rates of shoreline erosion over short time periods and from individual events like hurricanes, the cumulative impact over long time periods is low. Therefore, while the short-term response of these shorelines to episodic forcing should be taken into account in management plans, the long-term trends commonly used in ocean shoreline management can also be used to determine erosion setbacks on estuarine shorelines. [ABSTRACT FROM AUTHOR]

With declining availability of fresh surface water, brackish groundwater is increasingly used for irrigation in the arid and semi-arid southwestern United States. Brackish water can be desalinated by reverse osmosis (RO) but RO results in a highly saline concentrate. Disposal of concentrate is a major problem hindering augmentation of inland desalination in arid areas. The objective of this study was to determine the effect of texture and saline water irrigation on the physiology of six species (Atriplex canescens(Pursh) Nutt.,Hordeum vulgare L., Lepidium alyssoidesA. Gray,Distichlis stricta (L.)Greene,Panicum virgatum L., and ×TriticosecaleWittm. ex A. Camus [Secale × Triticum]). All species were grown in two contrasting soils and irrigated with the same volume of control water (EC 0.9 dS/m), brackish groundwater (4.1 dS/m), RO concentrate (EC 8.0 dS/m). Several plant physiological measurements were made during the growing season including height, number of stem nodes, average internodal length, number of leaves, leaf length, photosynthetic rates, stomatal conductance rates, transpiration rates, leaf temperatures, stem water potential, and osmotic potential.P. virgatumwas the only species that showed significant decrease in plant height and growth with texture and irrigation water salinity. Except forA. canescensandL. alyssoides, number and length of leaves decreased with increasing salinity for all species. No significant differences were observed for photosynthetic, stomatal conductance, and transpiration rates by soil texture or irrigation water salinity. Stem water potential and osmotic potential did show some significant influence by soil texture and irrigation water salinity. Based on the results, RO concentrate can be reused to grow all six species in sand; however, growth of all species showed some limitations in clay. Local reuse of RO concentrate along desert margins with regular soil and environmental quality monitoring can accelerate implementation of inland desalination for sustaining food security. [ABSTRACT FROM PUBLISHER]

Non-indigenous jellyfish species (NIJS) Blackforida virginica have recently been introduced to the Guadiana Estuary. A modelling approach was used for the assessment of the species-specific impact on the native community, during the medusa phase. The novel interactions between NIJS and the native community are assessed through biomass variation including hydrodynamic and climatic variables. Sensitivity analysis shows that both native species, as well as NIJS highly depend on the water discharge regime, nutrient contribution and the amount of detritus production. Abiotic factors such as the Northern Atlantic Oscillation, water discharge, nutrient load and detritus production are the most influential factors for the dynamics of the estuarine ecosystem demonstrated by the model. Low water discharge and low nutrient retention rate appear to be the most favourable conditions for B. virginica . The species is a non-selective predator able to integrate into the system effectively and has caused a decrease in the biomass of other organisms in the estuarine ecosystem throughout the summer after dam removal. The B. virginica significant impact can be evaluated only when the jellyfish detritus food pathway is involved. The B. virginica predatory impact potential, as well as food preference, appears to be the most influential factors for the overall biomass variation. On the contrary, winter freshwater pulses reduce the survival rate of jellyfish polyps which results in a decrease of medusa during summer. The model presents a strong ecohydrology movement where the fluctuation of organism biomass strongly depends on the hydrological conditions including the amount of nutrient load. [ABSTRACT FROM AUTHOR]

Currently, there is limited knowledge on how benthic communities function in relation to changing environmental conditions in tropical estuaries. This study contributes to filling this knowledge gap by analysing structural and functional community patterns within two tropical estuaries in the northeast of Brazil. Replicate macrofaunal samples were taken in different environmental zones along the estuary, together with physico-chemical measurements. The faunal analysis focussed on the trait analysis of polychaete and mollusc communities as both of these groups have an important role in regulating the functioning of aquatic systems. The separate analyses of polychaetes and molluscs allowed evaluating the way in which each group responded to the environmental gradients. The results demonstrate that community functioning for the polychaetes depended greatly on the spatial environmental gradients within these systems, with generally higher functional diversity in the lower zones suggesting increased diversity in resource use strategies, whereas the upper zones showed very little functional diversity due to the prevalence of environmental filtering. In the case of the molluscs, their functioning remained more similar along the estuarine gradient, with low taxonomic and functional diversity throughout the estuaries. In general, polychaetes displayed higher levels of taxonomic and functional diversity, suggesting that compared to the molluscs, they potentially utilised the available resources more efficiently, which may enhance the processes and overall functioning of these systems. We advocate that more studies are needed to obtain a generalised pattern of estuarine function within and across biogeographical regions. [ABSTRACT FROM AUTHOR]

One new genus and two new species of hypotrich ciliates isolated from brackish-water habitats in China were investigated. The new genus Polystichothrix gen nov. is defined by having a continuous adoral zone and more than 18 frontal-ventral-transverse cirri; undulating membranes in Oxytricha-pattern; three clearly differentiated frontal cirri; frontal and ventral cirri aligned in rows; one marginal cirral row on each side of the cell; more than three dorsal kineties; buccal cirrus and transverse cirri present. Polystichothrix monilata sp. nov. can be recognized by having a citrine-brownish cell colour caused by its citrine-yellow cortical granules; two frontal rows with a frontoventral cirrus to the left of them; four or five postoral ventral cirri; four or five short ventral rows; five dorsal kineties; about eight moniliform macronuclear segments. Lamtostyla ovalis sp. nov. is characterized by an ovoidal, flexible body; an amphisiellid median cirral row comprising about 11 cirri; about four frontoventral cirri; two pretransverse ventral and five transverse cirri; three dorsal kineties. We also provide the first record of the small subunit ribosomal RNA gene sequences for the genera Lamtostyla and Polystichothrix gen. nov. Phylogenetic analyses show that Pol. monilata sp. nov. is a member of the family Oxytrichidae, and that L. ovalis sp. nov. should be assigned to the family Amphisiellidae, although neither family is monophyletic. [ABSTRACT FROM AUTHOR]

Species compositions in highly seasonal habitats often exhibit predictable patterns through time. However, the roles that ecological interactions play in shaping the sequence of species phenologies through a season are largely unexplored. Across the tundra on the Hudson Bay Lowlands, extensive foraging by lesser snow goose populations has been driving alterations to the landscape. Here, I show that this widespread and dramatic disturbance increases evaporation rates of ephemeral ponds and consequently constricts the temporal availability of seasonal aquatic habitats for larval mosquitoes. I also show that this constriction decreases the temporal diversity of closely related univoltine mosquito species that have varying emergence schedules. Three species of mosquitoes emerged through the season from four sampled ephemeral ponds associated with no goose grubbing; only one species emerged, early in the season, from the four ponds that experienced heavy grubbing. This study demonstrates a mechanism for temporal composition change in a ubiquitous and abundant group of arthropods on the tundra. It does not show life history evolution of emergence time of mosquitoes; however, it highlights the rather unexplored role of ecological interactions in altering the diversity of phenologies across seasonal time. [ABSTRACT FROM AUTHOR]

The morphology, ciliary pattern and small subunit rDNA (SSU rDNA) sequences of two new cyrtophorian ciliates, Aegyria foissneri sp. n. and Lynchella minuta sp. n., isolated from brackish waters in southern China, were investigated. Aegyria foissneri sp. n. is characterized as follows: cell size 85–170 × 45–80 μm in vivo; body inverted oval with a protrusion and a dark pigment spot on anterior left part; 42–77 somatic kineties; one preoral and three to six circumoral kineties; five to eight transpodial segments; 31–44 nematodesmal rods; 12–16 contractile vacuoles; and single oval macronucleus. Lynchella minuta sp. n. is distinguished from its congeners by having a cell size of 20–30 × 15–20 μm in vivo, oval body outline; four preoral and 14 or 15 postoral kineties, three circumoral kineties; ca. 11 nematodesmal rods; one finger-like tentacle on the ventral side; and two diagonally located contractile vacuoles. Molecular phylogenetic analyses support the genus assignment of Aegyria foissneri sp. n. and indicate the monophyly of the genus. While Lynchella minuta sp. n. clusters with Coeloperix species, which indicates that Lynchella is non-monophyletic. [ABSTRACT FROM AUTHOR]