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da Silva, Renan B., Giovanni A. P. Dos Santos, Ana Luiza L. de Farias, Débora A. A. França, Raianne Amorim Cavalcante, Eliete Zanardi-Lamardo, Jose Roberto Botelho de Souza, and Andre M. Esteves. "Effects of PAHs on meiofauna from three estuaries with different levels of urbanization in the South Atlantic." PeerJ 10 (December 2, 2022): e14407. http://dx.doi.org/10.7717/peerj.14407.
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Estuarine environments are suggested to be the final receivers of human pollution and are impacted by surrounding urbanization and compounds carried by the river waters that flow from the continent. Polycyclic aromatic hydrocarbons (PAHs) are among the contaminants that can reach estuaries and can directly affect marine conservation, being considered highly deleterious to organisms living in these environments. This research investigated the meiofauna of three estuaries exposed to different levels of urbanization and consequently different levels of PAH concentrations, in order to assess how these compounds and environmental factors affect the distribution, structure and diversity of these interstitial invertebrates. A total of 15 major meiofauna groups were identified, with Nematoda being the dominant taxon (74.64%), followed by Copepoda (9.55%) and Polychaeta (8.56%). It was possible to observe significant differences in all diversity indices studied in the estuaries. With the exception of average density, the diversity indices (richness, Shannon index and evenness) were higher in the reference estuary, Goiana estuarine system (GES). On the other hand, the Timbó estuarine system (TES) had the lowest Shannon index value and richness, while the Capibaribe estuarine system (CES) had the lowest evenness value. The latter two estuaries (TES and CES) presented intermediate and high levels of urbanization, respectively. The ecological quality assessment (EcoQ) in the studied estuaries was classified from Poor to Moderate and the estuary with the lowest demographic density in its surroundings, GES, showed a better ecological quality (Moderate EcoQ). A significant distance-based multivariate linear modelling regression (DistLM) was observed between the environmental variables and the density of the meiobenthic community, where PAHs and pH were the main contributors to organism variation. The sediments were characterized by predominance of very fine sand and silt-clay in the most polluted environments, while the control site environment (GES) was dominated by medium grains. The highest concentrations of PAHs were found in the most urbanized estuaries, and directly affected the structure of the interstitial benthic community. The metrics used in the present study proved to be adequate for assessing the environmental quality of the investigated estuaries.
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O'Mara, K., A. Miskiewicz, and M. Y. L. Wong. "Estuarine characteristics, water quality and heavy metal contamination as determinants of fish species composition in intermittently open estuaries." Marine and Freshwater Research 68, no. 5 (2017): 941. http://dx.doi.org/10.1071/mf15409.
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Estuaries are critical aquatic environments that are used by many fish during their life cycle. However, estuaries often suffer from poor water quality as a result of anthropogenic activities. Fish diversity studies in estuaries are common, although few have examined whether correlations exist between water quality, metal contamination and fish assemblages. In the present study we investigated the effect of abiotic conditions, heavy metals and estuary characteristics on the abundance, diversity and composition of fish in four intermittently open estuaries along the Illawarra coast of south-eastern Australia. The heterogeneity of environmental conditions was reflected in the fish assemblages in each estuary. Environmental variables predicted fish species composition, and estuaries in particularly poor condition contained few species (estuarine residents) in high abundance, indicating their ability to acclimatise and survive in conditions that are hostile to other species. Overall, these findings demonstrate that estuarine fish assemblages may be useful indicators of estuary condition and reveal the importance of managing anthropogenic activities in the surrounding catchment to improve water quality so that biodiversity of fish can be restored in these estuarine environments.
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Nayak, Ganapati Narayan. "Changing Tropical Estuarine Sedimentary Environments with Time and Metals Contamination, Cest Coast of India." Journal of The Indian Association of Sedimentologists 38, no. 2 (December 31, 2021): 63–78. http://dx.doi.org/10.51710/jias.v38i2.141.
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Estuaries are one of the major sub-environments of the coastal zone wherein freshwaters interact and mix with saline waters, and facilitate deposition of finer sediments, organic matter, and metals. Intertidal mudflat and mangrove sediment cores collected from estuaries along the central west coast of India were investigated for various sedimentological and geochemical parameters to understand the changes in the sedimentary depositional environments and various factors influencing the processes. Additionally, estuarine biota was examined to understand the bioaccumulation of metals with respect to bioavailability. The results indicated considerable changes in the depositional environments with time owing to sea-level changes; geomorphology of the estuaries; rainfall and river runoff; anthropogenic activities including construction of dams and bridges. The sediments in the estuaries are considerably polluted by metals and pose toxicity risks to the estuarine biota due to high metal bioavailability. Marine gastropods and mangrove plants act as prospective bio-indicators, and the bioremediation potential of mangroves for contaminated sediments was identified. Metal bioaccumulation in edible benthic biota can be harmful to the human health.
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McCall, Grant S., Russell Greaves, Robert Hitchcock, Brian Ostahowski, Sherman W. Horn, and Muhammad I. Rehan. "The Estuarine Ecological Knowledge Network: Future Prospects." Marine Technology Society Journal 55, no. 3 (May 1, 2021): 122–23. http://dx.doi.org/10.4031/mtsj.55.3.31.
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Abstract Estuaries are profoundly rich, diverse, and complex ecosystems, and crucial to the overall health of Earth's oceans. Estuarine ecological complexity is matched by tremendous human cultural diversity. In the United States, millions of people live in estuarine environments from the Gulf of Mexico to the Arctic—many of whom directly depend on the productivity of marine resources in both commercial and subsistence fishing activities. Yet, estuaries are also among Earth's most threatened landscapes against the backdrop of global warming, sea-level rise, agricultural and industrial pollution, habitat loss, overfishing, and so on. This represents a looming disaster for our oceans at a global scale. The Estuarine Ecological Knowledge Network (EEKN) is based on the idea that fishing communities living within major estuaries are the key to ensuring the health of global oceans. Coastal fishing communities have vast accumulations of ecological knowledge about the functioning of estuarine ecosystems and interact with those ecosystems in intimate ways on a daily basis. This network is designed to connect coastal communities in monitoring the health of estuarine ecosystems and in using traditional ecological knowledge to develop strategies for enhancing ecosystem health and resilience.
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GIMENEZ, BARBARA C. G., and PAULO LANA. "Functional redundancy in polychaete assemblages from a tropical Large Marine Ecosystem (LME)." Zoosymposia 19, no. 1 (December 28, 2020): 72–90. http://dx.doi.org/10.11646/zoosymposia.19.1.11.
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Functional redundancy assumes a critical relevance nowadays due to the serious threats that affect marine life worldwide. We assessed and compared levels of functional redundancy in polychaete assemblages from the continental shelf and from estuarine environments along the South Brazil Shelf Large Marine Ecosystem (SBSLME). To quantify functional redundancy, we used functional originality (FOri) and functional uniqueness (FUni). We found 57 and 47 polychaete taxa distributed in 48 and 41 functional entities (i.e., a unique combination of trait values) in continental shelf and estuarine environments, respectively. Results suggest a low level of functional redundancy in both environments. However, FOri was higher in the estuarine environment, whereas FUni was higher in the continental shelf. As expected, estuarine polychaetes have fewer unique combinations of trait values, but these combinations are more original and adequate to the varying conditions imposed by estuarine environmental drivers.
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Gleire Rodrigues de Menezes, Francisca, Soraya Silva Neves, Rafael Dos Santos Rocha, Oscarina Viana Sousa, Marina Teresa Rodriguez Torres, Rodrigo Maggioni, Ernesto Hofer, and Regine Helena Silva dos Fernandes Vieira. "PATHOGENIC POTENTIAL OF Vibrio parahaemolyticus ISOLATED FROM TROPICAL ESTUARINE ENVIRONMENTS IN CEARÁ, BRAZIL." Revista de Patologia Tropical / Journal of Tropical Pathology 49, no. 2 (July 13, 2020): 94–104. http://dx.doi.org/10.5216/rpt.v49i2.61338.
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Vibrio parahaemolyticus is a potentially pathogenic bacterium that occurs naturally in estuarine environments worldwide. This research aimed to investigate the occurrence of Vibrio parahaemolyticus in estuarine environments and determine the virulence profile in aquaculture environment by molecular techniques and conventional microbiological methods. The analysis included 64 samples of water (n=32) and sediment (n=32) collected in estuaries. The samples yielded 64 strains suspected to be V. parahaemolyticus. The isolates were submitted to biochemical identification using a dichotomous key and PCR for the detection of the species-specific gene tl. Virulence was assessed by testing for urea hydrolysis and ?-hemolysis in erythrocytes (Kanagawa phenomenon) and simultaneous detection of the genes tdh and trh. All but one of the isolates (63/64) were confirmed to be V. parahaemolyticus by genotypic detection of tl. The genes tdh and trh were detected in 57 and 19 isolates, respectively. The Kanagawa test was positive for 51 isolates. Only one isolate was positive for urease. The incidence of tdh/trh-positivity was very high in strains isolated from the environment. The present study demonstrates that the necessity to improve the knowledge of the ecology and pathogeny of V. parahaemolyticus.
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Silva Junior, Milton Goncalves, Antonio Carlos Leal Castro, and Ulrich Saint-Paul. "Comparative Analysis of Distribution of Intertidal Fish Assemblages in Different Estuarine Systems on Northern Coast of Brazil." Journal of Sustainable Development 10, no. 2 (March 30, 2017): 26. http://dx.doi.org/10.5539/jsd.v10n2p26.
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The northern coast of Brazil has more than 30 estuaries distributed along 650 km of coastline. These conditions favor the presence of relatively large fish communities in estuarine environments, but published information on the fish fauna in tidal creeks in northern Brazil is only available for some mangrove systems, and comparative studies between fish estuarine communities in different tidal creeks are less common. The choice of the study area was based on the fact that it has been poorly investigated with regard to estuarine fish fauna in comparison in mangrove tidal creeks using the same fishing gear. The objective of the present study was to compare the composition of the relative biomass of taxonomic, functional and ecological guilds of fish assemblages occurring in estuarine systems along the northern coast of Brazil. The study area of the present comparative analysis extended from the southeastern edge of the Marajoara Gulf to the western edge of the Maranhense Gulf. A comparative analysis among different estuarine systems was performed using data from other studies. The abundance of juveniles was greater in the Caeté, Curuçá and Cururuca estuaries than other estuaries. Cluster analysis separated the estuaries into two distinct groups and significant differences between these groups only exist in relation to geographical proximity. The present investigation indicates that the coastal region between the states of Pará and Maranhão is characterized by high dynamics and environmental heterogeneity, particularly with regard to changes in river discharge and tidal fluctuations. The present results underscore the importance of ecological information on ichthyofauna in tropical estuaries in order to include appropriate descriptors in conservation or restoration processes of marine communities and habitats.
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Cunjak, R. A., R. L. Saunders, and E. M. P. Chadwick. "Seasonal Variations in the Smolt Characteristics of Juvenile Atlantic Salmon (Salmo salar) from Estuarine and Riverine Environments." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 4 (April 1, 1990): 813–20. http://dx.doi.org/10.1139/f90-094.
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Smolt characteristics such as lipid-moisture dynamics, ATPase activity, salinity tolerance, and condition factor were determined for Atlantic salmon parr (Salmo salar) moving to, or residing in, estuaries of two rivers in eastern Canada. Lipid and water content and gill Na+K+-ATPase activity of these parr differed markedly from river-resident parr. ATPase activity, sex ratio, and condition factor indicated more similarity between estuarine parr and smolts. Estuarine parr were unable to tolerate high salinities in spring, summer, or autumn, but there was an indication of an autumnal increase in salinity tolerance which coincided with maximum levels in ATPase activity and a secondary downstream movement of parr and smolt-like salmon in the autumn. The data suggest that the largest estuarine parr are essentially presmolts which utilize the estuary as a rearing environment prior to subsequent emigration seaward when environmental conditions are again amenable to a reopening of the 'smolt window.' These observations also highlight some inadequacies in applying existing criteria for the smoking process and for modelling life histories of salmonids.
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Mohajerin, T. Jade, George R. Helz, and Karen H. Johannesson. "Tungsten–molybdenum fractionation in estuarine environments." Geochimica et Cosmochimica Acta 177 (March 2016): 105–19. http://dx.doi.org/10.1016/j.gca.2015.12.030.
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Milne, R. A., P. C. Nicholas, C. Pattinson, and W. Halcrow. "The Definition of Effluent Discharge Consent Conditions in Complex Estuarine Environments." Water Science and Technology 18, no. 4-5 (April 1, 1986): 267–76. http://dx.doi.org/10.2166/wst.1986.0202.
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The Welsh Water Authority puts considerable emphasis upon the scientific determination of discharge consents through which it controls coastal pollution. It also pursues a policy which encourages the effective use of estuarine and coastal capacity to assimilate effluents. Conflict between environmental protection and cost-effective effluent disposal is minimised by concentrating upon the relationships between environmental quality objective (E.Q.O.), environmental quality standard (E.Q.S.) and discharge consent. Welsh Water has devoted considerable resources to the understanding and prediction of these relationships in estuaries and has developed a protocol for consent setting. This protocol is described and illustrated with examples from recent work on the Loughor and Dee estuaries in Wales. Desk study, specialised investigations and mathematical modelling techniques are integrated to identify critical processes in the dispersal, degradation and biological impact of pollutants. These are modelled to predict effluent behaviour for various discharge regimes, allowing a flexible approach to the selection of a consent.
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Zhuang, Mei, Edmond Sanganyado, Liang Xu, Jianming Zhu, Ping Li, and Wenhua Liu. "High Throughput Sediment DNA Sequencing Reveals Azo Dye Degrading Bacteria Inhabit Nearshore Sediments." Microorganisms 8, no. 2 (February 9, 2020): 233. http://dx.doi.org/10.3390/microorganisms8020233.
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Estuaries and coastal environments are often regarded as a critical resource for the bioremediation of organic pollutants such as azo dyes due to their high abundance and diversity of extremophiles. Bioremediation through the activities of azoreductase, laccase, and other associated enzymes plays a critical role in the removal of azo dyes in built and natural environments. However, little is known about the biodegradation genes and azo dye degradation genes residing in sediments from coastal and estuarine environments. In this study, high-throughput sequencing (16S rRNA) of sediment DNA was used to explore the distribution of azo-dye degrading bacteria and their functional genes in estuaries and coastal environments. Unlike laccase genes, azoreductase (azoR), and naphthalene degrading genes were ubiquitous in the coastal and estuarine environments. The relative abundances of most functional genes were higher in the summer compared to winter at locations proximal to the mouths of the Hanjiang River and its distributaries. These results suggested inland river discharges influenced the occurrence and abundance of azo dye degrading genes in the nearshore environments. Furthermore, the azoR genes had a significant negative relationship with total organic carbon, Hg, and Cr (p < 0.05). This study provides critical insights into the biodegradation potential of indigenous microbial communities in nearshore environments and the influence of environmental factors on microbial structure, composition, and function which is essential for the development of technologies for bioremediation in azo dye contaminated sites.
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Feldman, Howard R., Christopher G. Maples, Allen W. Archer, Ronald R. West, and Erik P. Kvale. "An estuarine model for Pennsylvanian Lagerstätten." Paleontological Society Special Publications 6 (1992): 95. http://dx.doi.org/10.1017/s2475262200006559.
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Estuaries were important sites of deposition throughout most of the Pennsylvanian in the Midcontinent. Modern estuaries typically occur within flooded river valleys where marine and fresh waters mix. Characteristic estuarine circulation results in locally high rates of deposition of muddy sediment that can lead to good preservation of fossils. Several Pennsylvanian conservat-Lagerstätten are best interpreted as having formed within ancient estuaries. Three types of estuarine deposits have been identified. Type 1 estuarine systems are large-scale transgressive systems that start with fluvial sands overlying an erosional surface. This is overlain successively by middle-estuarine laminated mudstone, and finally marine mudstone and shale. Well-preserved fossils occur in laminated mudstones and siltstones. This sequence may include within in it type 3 estuarine Lagerstätten. An example is the Douglas Group (Missourian, Kansas).Type 2 estuarine Lagerstätten consist of thin estuarine deposits confined to narrow paleochannels. This includes the Garnett (Missourian, Kansas) and Hamilton (Virgilian, Kansas) deposits, both of which contain articulated vertebrates and well-preserved plants. Both channels are filled with mixed siliciclastic and carbonate sediments. Fine grained facies from which the best fossils are recovered in both contain evidence of tidal deposition, although tidal rhythmicity is best developed in the Hamilton channel. Plant assemblages in both are dominated by the conifer Walchia, probably indicating a relatively dry climate.Type 3 estuarine Lagerstätten consist of thick gray-shale wedges that overlie coals. The best-known example is the Francis Creek Shale (Desmoinesian, Illinois). A relatively wet climate is indicated by abundant fern and seed-fern foliage. Laminations in shale facies commonly show well-developed tidal rhythmicity. A typical stratigraphic succession starts with laminated shale overlying coal. This grades upwards into flaser and lenticular bedding to ripple and then large-scale cross-bedded sandstone. Upright trees rooted in the coal indicate rapid burial. Well-preserved fossils are recovered from early-diagenetic siderite concretions from the laminated shale.Preservation of fossils is best in laminated mudstones deposited in middle-estuarine environments where conditions are ideal for good preservation. In all cases so far studied the zones of best preservation are well laminated and have sparse (if any) burrows and sessile benthic fossils. Most of the well-preserved organisms are terrestrial, nektonic, or at least mobile. Brackish and fluctuating salinities restricted scavenging and burrowing organisms that may scatter skeletons. High turbidity and deposition rate may have further discouraged many organisms. Matching bedding rhythmicity with tidal cycles allows calculation of depositional rates of 1 cm or more of compacted sediment per 2-week neap-spring tidal cycle. This is consistent with the high rates of deposition known from modern tidal environments. High depositional rates assured that any organism that fell to the sea floor was buried in a few hours to a few days. Once buried anoxic conditions established around decaying carcasses may have led to early mineralization.
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Pita, Ana Laura, Luis Giménez, Noelia Kandratavicius, Pablo Muniz, and Natalia Venturini. "Benthic trophic status of aquatic transitional environments with distinct morphological and dynamic characteristics on the south-western Atlantic coast." Marine and Freshwater Research 68, no. 11 (2017): 2028. http://dx.doi.org/10.1071/mf16284.
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The benthic trophic status of Uruguayan coastal estuarine habitats (permanently open estuaries and open or closed coastal lagoons) was evaluated, twice in 1 year and at different spatial scales, using the amount and biochemical composition of the sedimentary organic matter. Nested hierarchical ANOVAs were applied to evaluate differences at the habitat level, among sites for each type of estuarine habitat (three estuaries and three lagoons) and between sectors located at different distances from the sea (inner v. outer sectors). Morphological and hydrodynamic differences between the two types of habitats explained site-to-site variations in eutrophic conditions in the open or closed coastal lagoons and meso-oligotrophic conditions in permanently open estuaries. These differences followed the patterns found for sediment grain size, with inner sectors (lower-energy areas) favouring the accumulation of finer sediments and higher amounts of degraded–detrital organic matter. In autumn, biochemical parameters indicated the dominance of aged and more degraded organic matter, with both types of habitats having a low nutritional value no matter which sector was considered. By contrast, in spring, biochemical composition showed the prevalence of fresh and more labile sedimentary organic matter with a high food value, especially in the outer sectors.
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Saldanha, Denise Santos, Jéssica Adriana De Oliveira Macedo, Dayane Raquel Da Cruz Guedes, and Diógenes Félix da Silva Costa. "ANÁLISE PRELIMINAR DOS SERVIÇOS ECOSSISTÊMICOS DO SISTEMA ESTUARINO DO RIO PIRANHAS-AÇU (RN)." Revista da Casa da Geografia de Sobral (RCGS) 21, no. 2 (September 30, 2019): 255–64. http://dx.doi.org/10.35701/rcgs.v21n2.544.
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As Áreas Úmidas (AUs) são ecossistemas inundados periodicamente, caracterizando-se como áreas naturais ou artificiais, apresentam uma biodiversidade totalmente adaptada às condições do ambiente. Tendo em vista o potencial ecológico, econômico surgiu a necessidade de se fazer um estudo dos serviços ecossistêmicos que esses ambientes apresentam. A pesquisa partiu da hipótese de que no complexo estuarino do rio Piranhas-Açu (RN) encontra-se uma diversidade significativa de áreas úmidas, decorrente da influência do clima semiárido. Deste modo, o presente estudo teve como objetivo realizar uma classificação dos serviços de provisão e culturalprestados pela área de estudo, que está localizada nos municípios de Macau e Porto do Mangue (RN). Para tanto, a metodologia empregada nesse trabalho foi dividida em duas etapas: 1) levantamento bibliográfico e cartográfico prévio da área; e 2) identificação preliminar dos serviços ecossistêmicos prestadas na zona estuarina Piranhas-Açu (RN). Pode-se constatar que os serviços ecossistêmicos identificados na zona estuarina foram listados de acordo com a classificação CICES, divididos em provisão (alimentação local/gastronomia; compostos químicos, biocombustíveis, entre outros) e culturais (remédios naturais, valor paisagístico, entre outros.). Sendo assim, estima-se que esta pesquisa venha a contribuir para estudos mais aprofundados sobre esta temática.Palavras-chave: Serviços ecossistêmicos; Áreas úmidas; CICES. ABSTRACTThe Wetlands are periodically flooded ecosystems, characterizing themselves as natural or artificial areas, biodiversity fully adapted to the environment. In view of the ecological potential, economic came the need to study the services ecosystems that these environments present. The research started from the hypothesis that in the estuarine complex of river Piranhas-Açu (RN), there is a diversity of wetlands, due to the influence of semi-arid climate. In this way, the present study had as objective to carry out a classification of the services of provision and cultural provided by the study area, which is located in the municipalities of Macau and Porto do Mangue (RN). Therefore, the methodology employed in this work was dividedintotwo steps: 1) bibliographic and cartographic survey of the area; and 2) preliminary identification of services ecosystems provided in the Piranhas-Açu (RN) estuarine area. Ecosystem services identified in the estuarine zone were listed according to the CICES classification, divided into local/gastronomy; chemical compounds, biofuels) and cultural (natural remedies, landscape value). Therefore, it is estimated that this research will contribute to more studies on this subject.Key words: Ecosystem services; Coastal wetlands; CICES.RESUMENLos humedales (UA) son ecosistemas periódicamente inundados, caracterizados como áreas naturales o artificiales, con una biodiversidad totalmente adaptada a las condiciones ambientales. En vista del potencial ecológico y económico, surgió la necesidad de estudiar los servicios ecosistémicos que presentan estos entornos. La investigación comenzó a partir de la hipótesis de que en el complejo estuarino Piranhas-Açu (RN) existe una diversidad significativa de humedales, debido a la influencia del clima semiárido. Por lo tanto, este estudio tuvo como objetivo clasificar la prestación y los servicios culturales prestados por el área de estudio, que se encuentra en los municipios de Macau y Porto do Mangue (RN). Por lo tanto, la metodología utilizada en este trabajo se dividió en dos etapas: 1) encuesta bibliográfica y cartográfica previa del área; y 2) identificación preliminar de los servicios ecosistémicos proporcionados en la zona estuarina de Piranhas-Açu (RN). Se puede ver que los servicios de los ecosistemas identificados en la zona del estuario se enumeraron de acuerdo con la clasificación CICES, divididos en suministro (comida / gastronomía local; compuestos químicos, biocombustibles, entre otros) y culturales (remedios naturales, valor paisajístico, entre otros.). Por lo tanto, se estima que esta investigación contribuirá a más estudios sobre este tema.Palabras clave: Servicios ecosistémicos; Humedales; CICES.
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Kirby, Michael Xavier. "Differences in growth rate and environment between Tertiary and Quaternary Crassostrea oysters." Paleobiology 27, no. 1 (2001): 84–103. http://dx.doi.org/10.1666/0094-8373(2001)027<0084:digrae>2.0.co;2.
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Many Tertiary species of Crassostrea appear to have inhabited shallow-marine environments where they produced extremely large and thick shells. In contrast, living Crassostrea species are restricted primarily by marine predation to brackish, hypersaline, and intertidal environments where they produce comparatively smaller and thinner shells. If Crassostrea populations have used estuarine environments as a refuge from predation since the Cretaceous, then their presence in fully marine environments after the Cretaceous is puzzling. In order to interpret differences in environment and shell size, I examined the paleoecology and sclerochronology of two marine and two estuarine populations. Results are consistent with the hypothesis that thicker shells in Tertiary Crassostrea titan deterred increased exposure to fully marine predation. Life spans and growth rates estimated from annually formed growth increments show that C. titan grew significantly faster in shell thickness, as well as lived two to three times longer, than Quaternary Crassostrea virginica. Similar or lower valve-height growth rates in C. titan, as well as thinner shell walls in the attachment area, are consistent with exposure to marine predation, but not with alternative factors, such as higher salinity or alkalinity. Thicker valves in C. titan resulted from the successive addition of chalky deposit layers, in contrast to C. virginica valves, which contain significantly less of this unusual shell structure. A high incidence of incomplete drill holes in juvenile C. titan shells demonstrates that their thick valves were successful in deterring muricid predation. The association of C. titan with other large suspension feeders (barnacles and pectenids), as well as with phosphatic-pellet sediments, suggests that elevated planktic productivity may have supported this reefal community and enabled C. titan to grow thicker shells. The occurrence of both shallow-marine and estuarine Crassostrea since the Cretaceous raises the possibility that estuaries have served as refugia from which populations have dispersed into fully marine environments multiple times through the Cenozoic.
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Govender, Joelene, Trishan Naidoo, Anusha Rajkaran, Senzo Cebekhulu, Astika Bhugeloo, and Sershen Sershen. "Towards Characterising Microplastic Abundance, Typology and Retention in Mangrove-Dominated Estuaries." Water 12, no. 10 (October 9, 2020): 2802. http://dx.doi.org/10.3390/w12102802.
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Plastic and, particularly, microplastic (MP) pollution is a growing research theme, dedicated largely to marine systems. Occurring at the land–sea interface, estuarine habitats such as mangroves are at risk of plastic pollution. This study compared MP pollution (level, morphotype, polymer composition, size and colour) across four South African estuaries, in relation to the built and natural environment. Mouth status, surrounding human population densities and land-use practices influenced the level and type of MP pollution. Systems that were most at risk were predominantly open estuaries surrounded by high population densities and diverse land use types. Microplastic levels and the diversity of types detected increased with increasing levels of anthropogenic disturbance. Overall, microfibres dominated in estuarine water (69%) and mangrove sediment (51%). Polyethylene (43%) and polypropylene (23%) were the dominant polymers overall. Weathered fishing gear, weathered packaging items and run-off from urban/industrial centres are probable sources of MP pollution. Increased run-off and river input during the wet/rainy season may explain the markedly higher MP loads in estuarine waters relative to the dry season. By contrast, MP deposition in mangrove sediment was higher during the dry season. Sediment MP abundance was significantly positively correlated with both pneumatophore density and sediment size (500–2000 µm). This study highlights the role of mangroves as MP sinks, which may limit movement of MPs into adjacent environments. However, under conditions such as flooding and extreme wave action, mangroves may shift from sinks to sources of plastic pollution.
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Blum, Linda, Karl F. Nordstrom, and Charles T. Roman. "Estuarine Shores: Evolution, Environments and Human Alterations." Estuaries 21, no. 3 (September 1998): 501. http://dx.doi.org/10.2307/1352850.
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Allen, J. R. L. "Estuarine shores. Evolution, environments and human alterations." Marine Geology 147, no. 1-4 (May 1998): 132–33. http://dx.doi.org/10.1016/s0025-3227(97)00053-4.
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Plummer, Duncan H., Nicholas J. P. Owens, and Rodney A. Herbert. "Bacteria—particle interactions in turbid estuarine environments." Continental Shelf Research 7, no. 11-12 (November 1987): 1429–33. http://dx.doi.org/10.1016/0278-4343(87)90050-1.
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Murray, Taryn S., Paul D. Cowley, Rhett H. Bennett, and Amber-Robyn Childs. "Fish on the move: connectivity of an estuary-dependent fishery species evaluated using a large-scale acoustic telemetry array." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 11 (November 2018): 2038–52. http://dx.doi.org/10.1139/cjfas-2017-0361.
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Connectivity — movements of animals between and among numerous habitats — and the factors (rhythmic cycles and environmental variables) influencing connectivity of juvenile Lichia amia (Teleostei: Carangidae) were assessed in complementary acoustic telemetry studies in two geographically separated estuaries (620 km apart) in South Africa. The studies were conducted within a nationwide array of acoustic receivers moored in estuaries and coastal waters. Tagged fish in both the Kowie (n = 21) and Goukou (n = 17) estuaries displayed high levels of multiple habitat connectivity, with 81% and 76% visiting nearby marine and estuarine environments, respectively. The presence of tagged L. amia within the tagging estuaries was significantly influenced by river and sea temperature (Kowie) and river inflow and moon phase (Goukou). Tidal phase, time of day, and season were found to significantly influence marine excursions undertaken by Kowie- and Goukou-tagged fish. Our study provides an assessment of connectivity among multiple estuarine, port, and marine habitats, relating those movements to rhythmic cycles and environmental variables, and highlights the benefits of tracking animals using an extensive acoustic receiver array that spans multiple habitats.
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Khojasteh, Danial, Steve Hottinger, Stefan Felder, Giovanni De Cesare, Valentin Heimhuber, David J. Hanslow, and William Glamore. "IMPACT OF SEA LEVEL RISE ON HYDRODYNAMICS OF ESTUARIES WITH RESTRICTED ENTRANCES." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 3. http://dx.doi.org/10.9753/icce.v36v.management.3.
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Worldwide, hundreds of millions of people who live on or near estuarine environments are vulnerable to sea level rise (SLR). Using clustering techniques and moving beyond static models and case studies, this study used a large ensemble of idealised estuary models of varying scale, geometry, level of entrance constriction, and SLR scenarios. It was found that tidal forcing, degree of entrance restriction, and estuarine length can primarily control the tidal dynamics of prismatic estuaries under SLR. Further, restricting an entrance can be presented as a potential solution to offset SLR induced tidal amplification if the associated impacts on entrance stability, navigation, and flooding are considered.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/vOptOAbqN3U
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Kumbier, Kristian, Rafael C. Carvalho, Athanasios T. Vafeidis, and Colin D. Woodroffe. "Comparing static and dynamic flood models in estuarine environments: a case study from south-east Australia." Marine and Freshwater Research 70, no. 6 (2019): 781. http://dx.doi.org/10.1071/mf18239.
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Static and dynamic flood models differ substantially in their complexity and their ability to represent environmental processes such as storm tide or riverine flooding. This study analysed spatial differences in flood extent between static (bathtub) and dynamic flood models (Delft3D) in estuarine environments with different morphology and hydrodynamics in order to investigate which approach is most suitable to map flooding due to storm surges and river discharge in estuarine environments. Time series of observed water levels and river discharge measurements were used to force model boundaries. Observational data, such as tidal gauge and water level logger measurements, satellite imagery and aerial photography, were used to validate modelling results. Flood extents were calculated including and excluding river discharge to quantify and investigate its effect on the mapping of flooding. Modelling results indicate that the mature estuarine system, which has largely infilled broad flood plains, requires a consideration of bottom friction and riverine discharge through dynamic modelling techniques, whereas static models may provide an alternative approach to map flooding at low cost and low computational expense in young lake-like estuarine systems that have not been infilled with sediments. Our results suggest that estuarine classifications based on geomorphological characteristics can potentially guide flood risk assessments in estuarine environments.
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Shih, Yi-Jia, Jung-Sheng Chen, Yi-Jen Chen, Pei-Yu Yang, Yi-Jie Kuo, Tsung-Hsien Chen, and Bing-Mu Hsu. "Impact of heavy precipitation events on pathogen occurrence in estuarine areas of the Puzi River in Taiwan." PLOS ONE 16, no. 8 (August 16, 2021): e0256266. http://dx.doi.org/10.1371/journal.pone.0256266.
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Pathogen populations in estuarine areas are dynamic, as they are subject to multiple natural and anthropogenic challenges. Heavy rainfall events bring instability to the aquatic environment in estuaries, causing changes in pathogen populations and increased environmental sanitation and public health concerns. In this study, we investigated the effects of heavy precipitation on the occurrence of pathogens in the Puzi River estuary, which is adjacent to the largest inshore oyster farming area in Taiwan. Our results indicated that Vibrio parahaemolyticus and adenovirus were the most frequently detected pathogens in the area. There was a significant difference (Mann-Whitney U test, p < 0.01) in water quality parameters, including total coliform, Escherichia coli, water temperature, turbidity, salinity, and dissolved oxygen, between groups with and without V. parahaemolyticus. In addition, the detection rate was negatively correlated with the average daily rainfall (r2 > 0.8). There was no significant difference between water quality parameters and the presence/absence of adenovirus, but a positive correlation was observed between the average daily rainfall and the detection rate of adenovirus (r2 ≥ 0.75). We conclude that heavy precipitation changes estuarine water quality, causing variations in microbial composition, including pathogens. As extreme weather events become more frequent due to climate change, the potential impacts of severe weather events on estuarine environments require further investigation.
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Xu, Chaobin, Mengting Qi, Weisheng Lin, and Xiaofei Li. "Nitrous Oxide from Abiotic Processes of Hydroxylamine and Nitrite in Estuarine and Coastal Ecosystems: A Review." Journal of Marine Science and Engineering 10, no. 5 (May 2, 2022): 623. http://dx.doi.org/10.3390/jmse10050623.
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Abiotic processes of nitrogen (N) are suggested to contribute to nitrous oxide (N2O) production; however, the important role of these processes in N2O emissions is invariably ignored. This review synthesized the main abiotic processes of hydroxylamine and nitrite and associated biogeochemical controls in estuarine and coastal ecosystems. Abiotic processes of hydroxylamine and nitrite are availably detected in estuarine and coastal environments. The abiotic processes of hydroxylamine contribute more to N2O production than the abiotic processes of nitrite in estuarine and coastal environments, suggesting that hydroxylamine plays an important role in N2O production. The isotopic fractionation effects of N can occur during the abiotic processes of hydroxylamine and nitrite and are enriched with the increasing rates of N reactions. In addition, abiotic processes of hydroxylamine and nitrite are highly dependent on pH, oxygen, Fe2+, Fe3+, and Mn4+ and are also triggered by the increasing substrate contents. These results suggest that abiotic processes of hydroxylamine and nitrite have been greatly concerned for the estuarine and coastal environments, whereas the dynamics of these processes are still sparse for projecting N fates and dynamics in response to environmental factors changes. This review highlights the importance of abiotic processes of N and associated environmental implications and presents the future trend of N cycling in estuarine and coastal environments.
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Mai, Ana Cecilia Giacometti, and João Paes Vieira. "Review and consideration on habitat use, distribution and life history of Lycengraulis grossidens (Agassiz, 1829) (Actinopterygii, Clupeiformes, Engraulididae)." Biota Neotropica 13, no. 3 (September 2013): 121–30. http://dx.doi.org/10.1590/s1676-06032013000300015.
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In this paper, we present a summary of the current knowledge of Lycengraulis grossidens, a widely distributed coastal fish that occurs from Belize to Argentina. This species is abundant in estuaries along the Southwest Atlantic Coast and is important for recreational fishing, and as bycatch of shrimp fisheries. We compiled data available on taxonomy, phylogeny, ecology, fisheries and organized conceptually the life cycle of the species according to modern estuarine-use classification. Our review showed that along its geographic distribution and inside some particular environments (i.e., estuaries and costal lagoons) the species have been classified in a variety of ways in order to describe the remarkable complexity of habitat use that varies from freshwater resident, anadromous, marine migrant, estuarine resident, marine stragglers, catadromous to semi-catadromous. We conclude that L. grossidens is able to reproduce either in freshwater or estuarine water and postulate that it has a high plasticity in habitat use and life history, with migratory and resident contingents in the same local population. There seems to be a latitudinal change in migratory behavior of this species along the South America Coast, prevailing anadromous or semi-anadromous pattern at higher latitudes and marine migrants at the tropical northeast coast of Brazil.
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Magalhães, Wagner F., and Francisco Barros. "Structural and functional approaches to describe polychaete assemblages: ecological implications for estuarine ecosystems." Marine and Freshwater Research 62, no. 8 (2011): 918. http://dx.doi.org/10.1071/mf10277.
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Polychaete assemblages are of special interest when studying dynamic environments such as estuaries because of their high plasticity in life strategies to cope with environmental variability. We tested the hypothesis that polychaete feeding guilds would be more related to environmental characteristics than to taxonomic composition. Polychaetes were sampled on two different occasions along three tropical estuarine systems in north-eastern Brazil. Different polychaete taxa replaced one another along the entire salinity gradient and the overall pattern from high- to low-salinity regions was from high species and feeding-guild diversities to dominance by a single species or a feeding group. We suggest that the relationships between structure and function of polychaete assemblages might provide a measure of the resilience of estuarine conditions; estuaries with a high redundancy in the trophic role of polychaetes might recover faster from disturbance and retain more natural ecological functions than those estuaries with low or no redundancy, because more species would have the capacity to expand their niches to compensate for the loss of neighbouring species. Integrative approaches allying species composition to their trophic role need to be thoroughly investigated to help understand such complex temporal and spatial organisation of benthic assemblages in estuaries.
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Ávila, Rafael André, Priscila Mulattieri Suarez Orozco, Mauro Michelena Andrade, and Osmar Olinto Möller. "Temporal Variability of Suspended-Solids Concentration in the Estuarine Channel of Patos Lagoon, Southern Brazil." Water 13, no. 5 (February 28, 2021): 646. http://dx.doi.org/10.3390/w13050646.
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The assessment of suspended-solids dynamics is crucial for the effective monitoring of estuarine environments. As the recurring in-situ sampling is usually problematic, the calibration of the backscattering from acoustic Doppler profilers has shown to be a reliable technique to estimate the suspended-solids concentration (SSC) in estuaries and rivers. In this study, we obtained a linear model that provides SSC estimates for the estuarine channel of Patos Lagoon by calibrating turbidity and acoustic data with in-situ concentration samples. The model output was analyzed in terms of its relationship with estuarine hydrodynamics and temporal variability. In this estuary, the supply of suspended solids is known to be due the runoff from its main tributaries, but also through the exchanges between the estuary and the coastal ocean. Both sources provide sediments and organic solids which affect water quality, geomorphology, and harbor operations. Results show that SSC is strongly linked to estuarine hydrodynamics, where concentrations increase with streamflow. During outflow periods, higher concentrations are associated with river runoff, whereas with inflow conditions they are induced by southern and southwesterly winds. However, relationship between SSC and streamflow is asymmetrical, meaning that the largest concentrations are majorly linked to outflow currents and downstream transport.
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Zampatti, Brenton P., Christopher M. Bice, and Paul R. Jennings. "Temporal variability in fish assemblage structure and recruitment in a freshwater-deprived estuary: The Coorong, Australia." Marine and Freshwater Research 61, no. 11 (2010): 1298. http://dx.doi.org/10.1071/mf10024.
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River regulation can diminish freshwater flows to estuaries and compromise estuarine functionality. Understanding biotic responses to altered flow regimes is imperative to effectively manage aquatic ecosystems. The present study investigated temporal variation in fish assemblage structure and the recruitment of catadromous fish in the Coorong estuary at the terminus of the Murray River, in south-eastern Australia. Over the three-year study period, freshwater inflows to the estuary diminished and ultimately ceased, disconnecting freshwater and estuarine environments. It was hypothesised that these conditions would lead to (1) increases in estuarine salinities and concomitant changes in fish assemblage structure and abundance, and (2) decreased recruitment of catadromous fish. As freshwater inflow decreased, salinities immediately downstream of a series of tidal barrages increased from brackish to marine–hypersaline, species richness and diversity decreased, freshwater and diadromous species became less abundant and assemblages were increasingly characterised by marine species. Furthermore, the abundance of young-of-year catadromous fish decreased dramatically. Excessive regulation of freshwater inflows is resulting in the Coorong estuary resembling a marine embayment, leading to a loss in species diversity. We suggest, however, that even small volumes of freshwater may promote diversity in estuarine fish assemblages and some recruitment of catadromous species.
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Goldberg, Paul, K. Pye, and J. R. L. Allen. "Coastal and Estuarine Environments: Sedimentology, Geomorphology and Geoarchaeology." American Journal of Archaeology 106, no. 1 (January 2002): 114. http://dx.doi.org/10.2307/507196.
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Arienzo, Michele, and Luciano Ferrara. "Environmental Fate of Metal Nanoparticles in Estuarine Environments." Water 14, no. 8 (April 15, 2022): 1297. http://dx.doi.org/10.3390/w14081297.
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In the last decade, metal engineered nanomaterials (ENMs) have seen an exponential use in many critical technologies and products, as well an increasing release into the environment. Coastal ecosystems worldwide may receive ENM-polluted waters and wastes, with a consequent alteration of habitats and contamination of aquatic biota. There is a scarcity of data regarding the fate of these emerging contaminants in such environments. Open issues include the determination of the sources, the quantification of the interactions with marine sediments, the bioaccumulation pathways, the ecotoxicology on marine fauna and the identification of the principal biotic and abiotic factors that may alter metal ENMs toxicity. Little is known about their potential transference into the food web, as well toxicity features and co-stressors of single or multiple ENMs under laboratory and real environmental conditions for various taxonomic phyla. This review reports current knowledge on the ecological impact of ENMs under the complex environmental conditions of estuary systems, identifies gaps in current knowledge and provides directions for future research.
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KONDO, RYUJI. "I-3. Bacterial sulphur cycle of estuarine environments." NIPPON SUISAN GAKKAISHI 78, no. 2 (2012): 277. http://dx.doi.org/10.2331/suisan.78.277.
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Roth, Lori C., and H. Rodger Harvey. "Intact protein modification and degradation in estuarine environments." Marine Chemistry 102, no. 1-2 (November 2006): 33–45. http://dx.doi.org/10.1016/j.marchem.2005.10.025.
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Oliveira, Vanessa, Newton C. M. Gomes, Adelaide Almeida, Artur M. S. Silva, Helena Silva, and Ângela Cunha. "Microbe-Assisted Phytoremediation of Hydrocarbons in Estuarine Environments." Microbial Ecology 69, no. 1 (July 8, 2014): 1–12. http://dx.doi.org/10.1007/s00248-014-0455-9.
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McGlashan, Derek J. "Coastal and Estuarine Environments: Sedimentology, Geomorphology And Geoarchaeology." Geomorphology 46, no. 3-4 (August 2002): 308–9. http://dx.doi.org/10.1016/s0169-555x(01)00169-6.
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Sánchez-Arcilla, Agustin, Daniel González-Marco, Neelke Doorn, and Andreas Kortenhaus. "Extreme values for coastal, estuarine, and riverine environments." Journal of Hydraulic Research 46, sup2 (December 2008): 183–90. http://dx.doi.org/10.1080/00221686.2008.9521953.
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Davis, Donald, and Robert Baumann. "Oil in Louisiana’s estuarine environments: A development model." Science in China Series B: Chemistry 44, S1 (August 2001): 230–39. http://dx.doi.org/10.1007/bf02884831.
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Pickens, BA, JC Taylor, MD Campbell, and WB Driggers. "Offshore snapper and shark distributions are predicted by prey and area of nearby estuarine environments in the Gulf of Mexico, USA." Marine Ecology Progress Series 682 (January 20, 2022): 169–89. http://dx.doi.org/10.3354/meps13925.
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Seascape ecology has demonstrated that marine fishes are associated with multiscale habitat characteristics; however, most species distribution models focus on only a few predictors (e.g. depth, temperature), and this limits knowledge of essential fish habitat characteristics. Our objectives were to (1) determine habitat associations of offshore predatory marine fishes using a comprehensive suite of predictors, including area of nearby estuarine environments, (2) assess variable influence, and (3) model the spatial distribution of selected fishes in the families Carcharhinidae and Lutjanidae. We hypothesized that the concept of coastal outwelling would be evidenced by species associations with areas of nearby estuarine environments, and prey abundance would correlate with predator distributions. Species distribution models were developed for 2 snapper and 3 shark species in the northern Gulf of Mexico, USA. We used 34 multiscale predictors to evaluate how fish probability of presence or catch per unit effort (CPUE) were associated with oceanography, geography, substrate, area of nearby wetlands and estuaries, and prey abundance. Boosted regression trees, a machine-learning technique, modeled the most influential variables and predicted distributions. Model validation showed an overall accuracy of 79-86%, and CPUE models explained >40% of model deviance. Oceanographic variables, particularly mixed layer depth, were most influential and most frequently selected. As hypothesized, predatory fish distributions were predicted by prey abundances, and shark distributions were predicted by area of nearby coastal wetlands and estuaries. Our findings suggest that spatial models can provide novel insights into prey associations and linkages of marine species with nearby wetlands and estuaries.
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Wang, Zhanghua, Hao Xu, Qing Zhan, Yoshiki Saito, Zhongfa He, Jianlei Xie, Xiao Li, and Yonghong Dong. "Lithological and Palynological Evidence of late Quaternary Depositional Environments in the Subaqueous Yangtze Delta, China." Quaternary Research 73, no. 3 (May 2010): 550–62. http://dx.doi.org/10.1016/j.yqres.2009.11.001.
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AMS 14C ages of post-glacial core sediments from the subaqueous Yangtze delta, along with sedimentary structures and distributions of grain size, pollen spores, and dinoflagellate cysts, show an estuarine depositional system from 13 to 8.4 cal ka BP and a deltaic system from 5.9 cal ka BP to the present. The estuarine system consists of intertidal to subtidal flat, estuarine, and estuarine-front facies, characterized by sand"mud couplets and a high sedimentation rate. The deltaic system includes nearshore shelf and prodelta mud featured by lower sedimentation rate, markedly fewer coastal wetland herbaceous pollens, and more dinoflagellate cysts. We explain the extremely high sedimentation rate during 9.2–8.4 cal ka BP at the study site as a result of rapid sea-level rise, high sediment load due to the unstable monsoonal climate, and subaqueous decrease of elevation from inner to outer estuary. A depositional hiatus occurred during 8.2–5.9 cal ka BP, the transition from estuarine to deltaic system, caused possibly by a shortage of sediment supply resulting from delta initiation in paleo-incised Yangtze valley and strong tidal or storm-related reworking in offshore areas. The subsequent development of deltaic system at the study site indicates accelerated progradation of Yangtze delta post-5.9 cal ka BP.
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Smythe, Susan R., and Ian Hutchinson. "Ecological plasticity in Carex lyngbyei: evidence from transplant experiments." Canadian Journal of Botany 67, no. 12 (December 1, 1989): 3618–24. http://dx.doi.org/10.1139/b89-443.
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Four populations of Carex lyngbyei from each of three estuaries with contrasting salinity regimes in northwestern North America (deltas of the Nanaimo, Skagit, and Squamish rivers) were grown in a reciprocal transplant experiment to determine the degree to which morphological differences were genetic or environmentally based. Shoot height, biomass per shoot, and aboveground biomass differences were generally not maintained in the transplant environment, suggesting that genetic control on morphological variation was weak. Transplant site salinity regimes had little effect on shoot density or survival. It is suggested that broadly adapted genotypes, capable of this sort of plastic response, may have a competitive advantage in these fluctuating estuarine environments. Key words: Carex lyngbyei, Pacific Northwest, plasticity, reciprocal transplants.
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Birch, Gavin F., and Marco A. Olmos. "Sediment-bound heavy metals as indicators of human influence and biological risk in coastal water bodies." ICES Journal of Marine Science 65, no. 8 (September 15, 2008): 1407–13. http://dx.doi.org/10.1093/icesjms/fsn139.
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AbstractBirch, G. F., and Olmos, M. A. 2008. Sediment-bound heavy metals as indicators of human influence and biological risk in coastal water bodies. – ICES Journal of Marine Science, 65: 1407–1413. Currently, many institutions are conducting or planning large, regional-scale ecosystem assessments of estuarine health. A full, integrated assessment of these environments requires a large suite of biological, physical, and chemical indicators, including sedimentary chemistry, ecotoxicology, benthic community structure, and bioaccumulation. This commitment is beyond the capacity of most organizations, and a simpler approach is required to accommodate limited financial resources. A case is made for the use of sedimentary heavy metals as an easy and inexpensive indicator. The advantages are that sediments identify the “pristine” condition and give baseline information against which future management strategies may be benchmarked, and that they differentiate solely human-induced change from natural variation. Sediment indicators in depositional environments are also less dynamic than those associated with water and biota. Our objective is to demonstrate that sediment-bound heavy metals data provide the spatial extent and magnitude of chemical change, as well as the risk of biological stress attributable to contamination in estuarine ecosystems. An assessment of this scheme involving seven New South Wales (Australia) estuaries suggests that sedimentary heavy-metal indicators used in a weight-of-evidence approach, with data collected during the recent Australian National Land and Water Resources Audit, enhances estuarine condition assessment.
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Fidélis, Teresa, Filipe Teles, Peter Roebeling, and Fayaz Riazi. "Governance for Sustainability of Estuarine Areas—Assessing Alternative Models Using the Case of Ria de Aveiro, Portugal." Water 11, no. 4 (April 23, 2019): 846. http://dx.doi.org/10.3390/w11040846.
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Estuaries are one of the most productive and complex types of ecosystems supporting a wide range of economic activities. Departing from a set of governance problems and emergent goals, such as sustainability or climate change adaptation faced by an estuarine case study area, Ria de Aveiro, in Portugal, this article assesses the adequacy of alternative governance models under the existing water resources legal framework and traditional political culture. It shows that apart from the centrally-based compliance model, all other alternatives require high degrees of institutional reforms. Moreover, although the model based on a dedicated new agency, long preferred by many users of Ria de Aveiro, is the most understandable and focused, it does not assure the pursuance of adaptability or collaboration, which are considered essential for estuary governance. As it relies on collective action and multi-level and multi-agent contexts, estuarine governance may require a new institutional design. Where one begins a process of institutional change, however, is not a simple issue to address and demands a deeper analysis, particularly on the types of required institutional changes, as well as on their impacts on policy and decision-making outcomes over estuarine environments and associated socio-ecological networks.
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Weinmann, Anna E., and Susan T. Goldstein. "Landward-directed Dispersal of Benthic Foraminiferal Propagules At Two Shallow-water Sites in the Doboy Sound Area (Georgia, U.S.A.)." Journal of Foraminiferal Research 47, no. 4 (October 1, 2017): 325–36. http://dx.doi.org/10.2113/gsjfr.47.4.325.
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Abstract Transport of foraminiferal propagules is an important mode of dispersal in benthic foraminifera. Known to occur from tidal marshes and estuaries to deep-water environments, the former are particularly vulnerable to ongoing climate change. Because rising sea levels can have profound implications on local salinity and associated faunal compositions, transport of foraminiferal propagules within these environments can be crucial for local assemblages to respond to changing conditions. Here we focus on a shallow-water environment in southeastern Georgia to evaluate whether propagule transport occurs evenly or whether it shows a predominant direction, such as land- or seaward. Two sites were sampled in the Doboy Sound area: the southern tip of Sapelo Island and a site on the North River located approximately 10 km inland. We applied the propagule method using the fine fraction of the sediments that contains the propagule bank. Experimental conditions in the laboratory included three temperatures (18, 24 and 30°C) and three salinities (15, 25 and 35) to simulate a range of environments that might trigger the growth of various foraminiferal species. While adult in situ assemblages of both sites were at least partly influenced by the adjacent salt marshes, experimentally grown assemblages were dominated by mudflat, estuarine or more open marine species. Thus, propagule transport from the more terrestrial side of the assemblage gradient is limited, while propagules of more marine species can be transported far into the extensive estuarine system of the study area, where they can remain viable within the local propagule banks. Results provide important insights into possible changes in foraminiferal assemblages with rising sea-level on the Georgia coast.
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Elsdon, Travis S., and Bronwyn M. Gillanders. "Alternative life-history patterns of estuarine fish: barium in otoliths elucidates freshwater residency." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 5 (May 1, 2005): 1143–52. http://dx.doi.org/10.1139/f05-029.
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Elemental concentrations in fish otoliths (earstones) can reconstruct environmental histories of fish if predictable relationships between the environment and elemental incorporation are established. We assessed whether fresh water occupancy of black bream (Acanthopagrus butcheri) can be inferred from otolith barium concentrations (Ba was standardized to calcium (Ca) and expressed as a ratio, Ba:Ca). Otolith Ba:Ca of fish was correlated with ambient Ba:Ca. Using the natural relationships of increasing ambient and otolith Ba:Ca with decreasing salinity, fish from fresh- and salt-water environments were distinguishable. Fish caught in fresh water had approximately double the otolith Ba:Ca of those from salt-water estuaries, for both summer and winter collections. Fish with otolith Ba:Ca ≤5 µmol·mol1 were classified as resident in salt water, and those with ≥6 µmol·mol1 as resident in fresh water. Transects of Ba:Ca across fish otoliths classified fish to fresh- or salt-water environments. Fish were identified as having migratory patterns typical of residents, migrants with irregular patterns of diadromy, or migrants with cyclic patterns of anadromomy. Multiple migratory behaviours occurred in fish from the same estuary, indicating far more complex migratory behaviours than were previously known. The application of otolith Ba:Ca to infer freshwater occupancy of fish has rarely been studied, yet may provide more accurate classifications of estuarine environments than strontium (Sr) isotopes and otolith Sr:Ca.
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Rozirwan, Redho Yoga Nugroho, Puspa Indah Wulandari, Riris Aryawati, Fauziyah, Wike Ayu Eka Putri, Andi Agussalim, and Isnaini. "Bacillariophyceae Distribution and Water Quality in Estuarine-Mangrove Environments: The Commonest Phytoplankton in Musi Estuary, Indonesia." Journal of Hunan University Natural Sciences 49, no. 12 (December 30, 2022): 78–88. http://dx.doi.org/10.55463/issn.1674-2974.49.12.8.
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This study reveals the distribution of Bacillariophyceae in estuarine-mangrove which is mainly influenced by the quality of the waters. The main component analysis approach between variables is critical in this study because it determines the environmental characteristics in each estuarine zone. Estuarine-mangrove environments have different physical-chemical dynamics compared to other types of waters, one of which is Musi Estuary, located on the coast of South Sumatra. The aquatic environment of the Musi Estuary is influenced by tidal fluctuations that bring nutrients from inland waters and mangrove litter. This condition is perfect for the phytoplankton habitat, which plays an essential role in the ecological processes of waters as primary producers. This study aims to examine the diversity of Bacillariophyceae phytoplankton in the mangrove estuary environment and its possible role in estuarine ecology. Data were collected at ten observation stations in July, including samples of phytoplankton and water physical-chemical data such as pH, dissolved oxygen, temperature, salinity, water brightness, current speed, nitrates, and phosphates. Quantitative measurement of phytoplankton was performed using an Olympus CX23 light microscope at 100X magnification, while data were analyzed using PCA and Bray-Curtis similarity analysis. Water environment conditions were measured in a stable range in each zone except for salinity and brightness. Furthermore, only Bacillariophyceae were observed in all observation zones dominated by the Skeletonema genus. It is a dominant presence, and its abundance determined its role as a significant primary producer in the estuary outer zone near the sea. This study implicitly revealed the existence of Skeletonema in influencing ecological processes in estuary mangrove waters.
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Dyson, I. A. "GREENSAND RESERVOIRS IN SILICICLASTIC SHORELINE SYSTEMS: FACIES MODELS FOR HYDROCARBON EXPLORATION." APPEA Journal 38, no. 2 (1998): 132. http://dx.doi.org/10.1071/aj97085.
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Greensand reservoirs are particularly significant in siliciclastic shoreline systems. Formation of autochthonous glauconite is restricted almost exclusively to the rising limb of the relative sea level (RSL) curve. Depositional environments that are typically developed in response to a rise in RSL are estuaries, barrier bars and shoreface sands. In this setting, the greensands are diachronous and exploration for hydrocarbon reservoirs should ideally be based on a sequence stratigraphic framework. These deposits are characterised by a number of significant surfaces that differ greatly in their origin, geographic extent and chronostratigraphic significance, and their thickness depends on the rate of RSL rise and sediment supply. The identification of significant surfaces bounding or contained within depositional sequences is critical, especially where drillhole samples are either unreliable or not available for geochemical and palynological analysis. Abrupt physical and chemical changes often occur on or across these surfaces, e.g. porosity, permeability and the presence of Fe-rich authigenic minerals such as glauconite and siderite. Greensands deposited in estuarine, barrier bar and shoreforce environments have excellent oil and gas potentail. Early Cretaceous greensand reservoirs from the North West Shelf are best developed where they overlie ravinement surfaces. Recognition of greensands within estuarine, barrier bar and shoreface environments is dependent on the correct identification of facies and the subsequent interpretation of the bounding discontinuities.
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Setiawan, Edwin, David Relex, and David J. Marshall. "Shallow-water Sponges from a High-sedimentation Estuarine Bay (Brunei, Northwest Borneo, Southeast Asia)." Journal of Tropical Biodiversity and Biotechnology 6, no. 3 (September 29, 2021): 66435. http://dx.doi.org/10.22146/jtbb.66435.
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Tropical estuaries are important habitats for invertebrates including sponges, a group of marine organisms that fulfill significant ecological roles and provide ecosystem services. Here, we describe the sponge fauna from Pulau Bedukang, a small island in a turbid, variable salinity, acidified and eutrophic estuarine bay (Brunei Darussalam, northwest Borneo). We present records for 14 morphological species (OTUs). Six of these species belong to the Haplosclerida, an order of shallow-water sponges that usually tolerate more variable and extreme physical conditions. Our baseline data contribute to the regional biogeography of sponges and present a reference source for ecological studies on marine animals inhabiting variable estuarine environments. This is the first known record of sponges from the northwest Bornean region of the South China Sea that are not associated with a coral ecosystem; other studies have concerned Singapore, peninsular Malaysia, Thailand, Cambodia, Vietnam, southern China, and Taiwan.
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Albuquerque, Cristiano Q. de, Norbert Miekeley, and José H. Muelbert. "Whitemouth croaker, Micropogonias furnieri, trapped in a freshwater coastal lagoon: a natural comparison of freshwater and marine influences on otolith chemistry." Neotropical Ichthyology 8, no. 2 (2010): 311–20. http://dx.doi.org/10.1590/s1679-62252010000200009.
Full textAbstract:
Strontium and barium incorporation into otoliths was compared between whitemouth croaker, Micropogonias furnieri, collected from an entrapped freshwater population (Mirim Lagoon) and a normal marine/estuarine population in southern Brazil. Chemical analysis was performed using LA-ICPMS with the objective of validating the effects of marine and freshwater environments on Sr and Ba incorporation as a basis for further investigation of marine and freshwater connectivity of M. furnieri. The freshwater population was dominated by older fish with mean ±SD age of 34±1 y, whereas the coastal samples were dominated by younger fish of 14±7 y. Comparison of strontium and barium incorporation among otolith life-history profiles indicated significantly higher barium and lower strontium for the freshwater population compared to the marine population. Furthermore, comparison of otolith material deposited in the freshwater, estuarine and marine life-history phases demonstrated clear differences among these environments. Mean concentrations of strontium and barium in otoliths of M. furnieri were respectively 710 and 112 µg g-1 for freshwater, 2069 and 16.7 µg g-1 for estuarine, and 2990 and 2.7 µg g-1 for marine life-history phases. Barium concentrations in otoliths from the freshwater population of M. furnieri appeared high relative to other freshwater species. Strontium levels across life-history profiles of marine fish increased with age from 2000 to 2900 µg g-1, possibly indicating more time spent in marine than estuarine waters with age. In contrast, for the freshwater population, strontium levels decreased during the first year of life approximately to 700 µg g-1, and remained low and stable thereafter, consistent with the early life-history occurring in an estuarine environment prior to entrapment in Mirim Lagoon. The results confirm the strong and opposite effects of marine and freshwater environments on incorporation of barium and strontium into otoliths, and indicate that the population of M. furnieri in Mirim Lagoon represents an isolated population that does not reproduce and is therefore likely to become extinct.
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Wang, Wen-Xiong, Jie Meng, and Nanyan Weng. "Trace metals in oysters: molecular and cellular mechanisms and ecotoxicological impacts." Environmental Science: Processes & Impacts 20, no. 6 (2018): 892–912. http://dx.doi.org/10.1039/c8em00069g.
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Blake, Lynsay I., Angela Sherry, Obioma K. Mejeha, Peter Leary, Henry Coombs, Wendy Stone, Ian M. Head, and Neil D. Gray. "An Unexpectedly Broad Thermal and Salinity-Tolerant Estuarine Methanogen Community." Microorganisms 8, no. 10 (September 24, 2020): 1467. http://dx.doi.org/10.3390/microorganisms8101467.
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Moderately thermophilic (Tmax, ~55 °C) methanogens are identified after extended enrichments from temperate, tropical and low-temperature environments. However, thermophilic methanogens with higher growth temperatures (Topt ≥ 60 °C) are only reported from high-temperature environments. A microcosm-based approach was used to measure the rate of methane production and methanogen community structure over a range of temperatures and salinities in sediment from a temperate estuary. We report short-term incubations (<48 h) revealing methanogens with optimal activity reaching 70 °C in a temperate estuary sediment (in situ temperature 4–5 °C). While 30 °C enrichments amended with acetate, H2 or methanol selected for corresponding mesophilic trophic groups, at 60 °C, only hydrogenotrophs (genus Methanothermobacter) were observed. Since these methanogens are not known to be active under in situ temperatures, we conclude constant dispersal from high temperature habitats. The likely provenance of the thermophilic methanogens was studied by enrichments covering a range of temperatures and salinities. These enrichments indicated that the estuarine sediment hosted methanogens encompassing the global activity envelope of most cultured species. We suggest that estuaries are fascinating sink and source environments for microbial function study.
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Tagliapietra, Davide, Marco Sigovini, and Annamaria Volpi Ghirardini. "A review of terms and definitions to categorise estuaries, lagoons and associated environments." Marine and Freshwater Research 60, no. 6 (2009): 497. http://dx.doi.org/10.1071/mf08088.
Full textAbstract:
Estuaries, rias, fjords, coastal lagoons, bahiras, river mouths, tidal creeks, deltas and similar coastal environments are often regarded as a single broad conceptual class. ‘Brackish’, ‘estuarine’, ‘paralic’ and ‘transitional’ are terms used in different contexts to designate collectively this class of environments. Nevertheless every term, generated from different historical perspectives and scientific points of view, excludes some of the above-mentioned environments. These terms and definitions were examined with regard to their meaning and history. The main attributes have been extracted from definitions and arranged in a conceptual scheme giving an overall direct perception of their relationships. This analysis provided evidence for the occurrence of two major groups of attributes: hydrological and geomorphic. Although the significance of hydrological attributes is instantly recognisable, geomorphic attributes imply subjacent concepts of geographical scale and hydrological features not expressly formulated in definitions, such as a limited supply of seawater to the system.