Artigos de revistas: "Estuarine mudflats"

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Braat, Lisanne, Thijs van Kessel, Jasper R. F. W. Leuven e Maarten G. Kleinhans. "Effects of mud supply on large-scale estuary morphology and development over centuries to millennia". Earth Surface Dynamics 5, n.º 4 (9 de outubro de 2017): 617–52. http://dx.doi.org/10.5194/esurf-5-617-2017.

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Abstract. Alluvial river estuaries consist largely of sand but are typically flanked by mudflats and salt marshes. The analogy with meandering rivers that are kept narrower than braided rivers by cohesive floodplain formation raises the question of how large-scale estuarine morphology and the late Holocene development of estuaries are affected by cohesive sediment. In this study we combine sand and mud transport processes and study their interaction effects on morphologically modelled estuaries on centennial to millennial timescales. The numerical modelling package Delft3D was applied in 2-DH starting from an idealised convergent estuary. The mixed sediment was modelled with an active layer and storage module with fluxes predicted by the Partheniades–Krone relations for mud and Engelund–Hansen for sand. The model was subjected to a range of idealised boundary conditions of tidal range, river discharge, waves and mud input. The model results show that mud is predominantly stored in mudflats on the side of the estuary. Marine mud supply only influences the mouth of the estuary, whereas fluvial mud is distributed along the whole estuary. Coastal waves stir up mud and remove the tendency to form muddy coastlines and the formation of mudflats in the downstream part of the estuary. Widening continues in estuaries with only sand, while mud supply leads to a narrower constant width and reduced channel and bar dynamics. This self-confinement eventually leads to a dynamic equilibrium in which lateral channel migration and mudflat expansion are balanced on average. However, for higher mud concentrations, higher discharge and low tidal amplitude, the estuary narrows and fills to become a tidal delta.

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Kleinhans, Maarten G., Lonneke Roelofs, Steven A. H. Weisscher, Ivar R. Lokhorst e Lisanne Braat. "Estuarine morphodynamics and development modified by floodplain formation". Earth Surface Dynamics 10, n.º 2 (29 de abril de 2022): 367–81. http://dx.doi.org/10.5194/esurf-10-367-2022.

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Abstract. Rivers and estuaries are flanked by floodplains built by mud and vegetation. Floodplains affect channel dynamics and the overall system's pattern through apparent cohesion in the channel banks and through filling of accommodation space and hydraulic resistance. For rivers, effects of mud, vegetation and the combination are thought to stabilise the banks and narrow the channel. However, the thinness of estuarine floodplain, comprised of salt marsh and mudflats, compared to channel depth raises questions about the possible effects of floodplain as constraints on estuary dimensions. To test these effects, we created three estuaries in a tidal flume: one with recruitment events of two live vegetation species, one with mud and a control with neither. Both vegetation and mud reduced channel migration and bank erosion and stabilised channels and bars. Effects of vegetation include local flow velocity reduction and concentration of flow into the channels, while flow velocities remained higher over mudflats. On the other hand, the lower reach of the muddy estuary showed more reduced channel migration than the vegetated estuary. The main system-wide effect of mudflats and salt marsh is to reduce the tidal prism over time from upstream to downstream. The landward reach of the estuary narrows and fills progressively, particularly for the muddy estuary, which effectively shortens the tidally influenced reach and also reduces the tidal energy in the seaward reach and mouth area. As such, estuaries with sufficient sediment supply are limited in size by tidal prism reduction through floodplain formation.

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Fouet, Marie P. A., David Singer, Alexandra Coynel, Swann Héliot, Hélène Howa, Julie Lalande, Aurélia Mouret, Magali Schweizer, Guillaume Tcherkez e Frans J. Jorissen. "Foraminiferal Distribution in Two Estuarine Intertidal Mudflats of the French Atlantic Coast: Testing the Marine Influence Index". Water 14, n.º 4 (18 de fevereiro de 2022): 645. http://dx.doi.org/10.3390/w14040645.

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This study focuses on the foraminiferal distribution on intertidal mudflats of two contrasted estuaries (Auray and Vie) along the French Atlantic coast. In both estuaries, the foraminiferal communities are dominated by Haynesina germanica and the Ammonia tepida group. Stations located near the outlets show a high diversity and abundance of species of the genus Elphidium. Stations in the inner estuary show a higher proportion of agglutinated species (Ammotium salsum, Ammobaculites agglutinans). Multivariate statistical analysis suggests that the distance to the sea and the percentage of fine sediment (<63 µm) are the two main parameters explaining the foraminiferal distribution. Chemical analyses of the sediment show that the two studied estuaries are not affected by major anthropogenic pollution, so that the faunas should mainly reflect the natural controlling parameters. Three indices of environmental quality commonly used in coastal areas show counter-intuitive differences between stations, suggesting that these indices may be less reliable for use in intertidal estuarine mudflats. The newly developed Marine Influence Index (MII) integrates three major ecological factors: the position of the sampling point on the salinity gradient, the emergence time at low tide and the relative importance of fresh water discharge. In our dataset, MII shows significant correlations with the controlling environmental parameters (distance to the sea, percentage grains < 63 µm), as well as with the foraminiferal patterns (PCA axis 1, species richness, percentage of Elphidium spp. and Quinqueloculina spp.). These results suggest that the MII explains a substantial part of the faunal variability on estuarine intertidal mudflats, and can be used to detect deviations from the natural distribution patterns in response to anthropogenic pollution.

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Defew, E. C., T. J. Tolhurst e D. M. Paterson. "Site-specific features influence sediment stability of intertidal flats". Hydrology and Earth System Sciences 6, n.º 6 (31 de dezembro de 2002): 971–82. http://dx.doi.org/10.5194/hess-6-971-2002.

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Abstract. The factors that influence the sediment stability and the transport of estuarine mudflats are not yet fully understood but knowledge of them is essential in coastal engineering applications and pollution ecology studies. The suggestion that variation in predictive models of sediment stability might be due to site-specific characteristics is investigated using data from four estuarine mudflats (Eden Estuary, Scotland, the Biezelingsche Ham, Zandkreek, and Molenplaat mudflats in The Netherlands). These estuaries differ in their environmental conditions, macrofaunal species composition and local features (e.g. Enteromorpha mats, migratory biofilms). Stable and unstable sediments were compared, and mean chlorophyll-a concentrations and granulometry of the sediments were significantly different between the two groups. Step-wise multiple linear regressions were applied to the sediment stability data of all sites to establish the influences on erosion threshold of microphytobenthic biomass, water content, granulometry, organic carbon content and the abundance of dominant macrofaunal species. The stability of each site was influenced by different factors. Sediment stability of the Eden Estuary was affected by the Enteromorpha bloom; Biezelingsche Ham was influenced by the highly migratory nature of the diatom biofilms and the abundance of Corophium volutator; the polychaete worm Arenicola marina had a net negative effect on sediment stability of the Zandkreek; and the Molenplaat was influenced by microphytobenthic biomass. This research highlights the need for site-specific calibration of models and suggests that a universal proxy parameter for sediment stability is unlikely to be obtained. Keywords: sediment stability; erosion threshold; cohesive strength meter; microphytobenthos; Enteromorpha spp.

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Kumaraguru, Arumugam, Rosette Celsiya Mary e Vijayaraghavalu Saisaraswathi. "A review about fish walking on land". Journal of Threatened Taxa 12, n.º 17 (26 de dezembro de 2020): 17276–86. http://dx.doi.org/10.11609/jott.6243.12.17.17276-17286.

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Mudskippers are amphibious species inhabiting semi-terrestrial ecosystems like mudflats, mangroves, marshy swamps, intertidal regions, and estuaries. Around 34 diversified species are found across the globe. Mudskipper belongs to the Oxudercidae family and the subfamily is Oxudercinae. The occurrence of species is vastly found across the Indo-West Pacific region, the tropical western coast of Africa and in the Indian Ocean. Mudskippers are known for being the biological indicator and also an indicator of estuarine safety monitoring. They are used by people for prey-catching baits. This review paper explains the ecological indicators, taxonomy, species diversity, habitat, behavioural pattern, respiration & kinematics, feeding ecology, reproduction, nutrition content & its medicinal value, and threats to mudskippers.

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Sapkale, J. B., T. R. Jamadar, S. J. Sapkale e G. S. Shinde. "Estimation of Physicochemical Properties in the Estuarine Water of Mithbav Tidal Mud Flats (Downstream Part), Coastal Maharashtra". Research Journal of Chemistry and Environment 27, n.º 10 (15 de setembro de 2023): 10–20. http://dx.doi.org/10.25303/2710rjce010020.

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Estuarine environments have become crucial in coastal areas nowadays. Mangrove swamps, mudflats and related estuarine environments provide a habitat for animals and encourage plant growth. For the people of coastal areas, estuaries are one of the vital sources of food and other economic activity. The imbalance in the quality and quantity of Estuarine water in terms of its physicochemical parameters causes adverse effects on marine life. In the present study, an attempt has been made to estimate the physicochemical properties of the estuarine water of Mithbav tidal mud flats (downstream part) of coastal Maharashtra. Several methods have been used to evaluate the variations in physical and chemical properties of estuarine water in Mithbav including standard water testing,1 the titration method and Winkler's method. Salinity, turbidity, pH, total hardness, DO, TDS, EC, nitrate, fluoride, phosphate, ammonium, magnesium, calcium, carbonate, chloride, sodium, potassium and sulphate were examined for the seven cross-sectional sites of Mithbav estuarine water. Some parameters show levels of contamination that exceed the maximum limit. For instance, during the post-monsoon season, the average value of dissolved oxygen (DO) was recorded as 11.57mg/L whereas it has been recorded as 8.07mg/L during the summer season. The total dissolved solids (TDS) showed an average increase from 141.54 to 348.57ppt between pre and post-monsoon seasons. The electrical conductivity (EC) also increased from 45558.17μ S/Cm to 31445.85 μ S/Cm respectively from the dry to the wet season. The fluoride levels during the post-monsoon season ranged from 1.07 mg/L at CS-1 to 4.2 mg/L at CS-6. The study shows that the Mithbav coastal ecosystem and nearby areas are at significant risk of contamination from physiochemical parameters that could harm the environment.

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Mathes-Schmidt, Margret, Denis Moiriat, Hervé Jomard, Klaus Reicherter e Stéphane Baize. "The Holocene sedimentary record of the flood plain of the Saint-Ciers-Sur-Gironde marsh (Gironde estuary, France)". Zeitschrift für Geomorphologie, Supplementary Issues 62, n.º 2 (1 de outubro de 2019): 295–322. http://dx.doi.org/10.1127/zfg_suppl/2019/0605.

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The Holocene sedimentary record of the flood plain of the Saint-Ciers-Sur-Gironde marsh was examined on sediment cores from the right bank of the Gironde estuary with regard to the evolution of the marsh and its potential to preserve high-energy deposits. Sedimentological, geochemical, geophysical and micropaleontological methods were applied. Radiocarbon ages in the central part of the investigation area reach back to 7,971 ± 44.5 BP. The sediments of the Saint-Ciers-sur-Gironde marsh reflect the condi- tions of a Holocene estuarine salt marsh before human activity and draining. The interpretation of the core data showed that the study area includes different facies during development from the pre-Holocene to recent times: tidal mudflats in the northwest at Mortagne and Beaumont, and a fluvial facies develop- ing into an estuarine facies in the southeast near Camp and Saint-Ciers-Sur-Gironde. The last stage is the formation of the saltmarsh. The changes in grain size reflect different transport mechanisms during the development from a fluvial environment to the recent marsh. First gravel, then sand and finally muddy sediments were deposited in the estuary and finally in the marsh area.. Below the salt marsh deposits in Mortagne-Sur-Gironde, there is some evidence of deposits from energy-rich events in tidal mudflats. The southern and central part, in which estuarine clays were deposited, was probably most of the time outside the range of storms. On the marshland surface, erosion, pedogenesis and bioturbation processes destroy storm relevant layers in a very short time.

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Groeneveld, Johan C., Fiona MacKay, Baraka Kuguru e Boniventure Mchomvu. "Socio-ecological change in the Ruvu Estuary in Tanzania, inferred from land-use and land-cover (LULC) analysis and estuarine fisheries". Western Indian Ocean Journal of Marine Science, n.º 1/2021 (23 de dezembro de 2021): 75–91. http://dx.doi.org/10.4314/wiojms.si2021.1.6.

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Ecosystem goods and services derived from estuaries have sustained coastal livelihoods in the Western Indian Ocean (WIO) region throughout recorded history. Estuaries provide fertile and seasonally irrigated space for planting crops, mangrove products for construction and fuel, and fish as a protein source. Human population growth and an escalating demand for natural resources threaten estuarine critical habitats and their functioning, exacerbated by the effects of climate change. Decadal and seasonal land-use and land-cover (LULC) changes in the Ruvu Estuary in Tanzania were investigated through analysis of Landsat 5/8 and Sentinel-2 satellite images. The estuary is river-dominated and truncated near the coast during high river flow, with tidal influence extending approximately 12 km upstream during low river flow. LULC change detection targeting nine classes (water, developed, barren, forest, grasslands, cultivated, mangroves, wetlands and mudflats) showed that estuary-associated wetlands and mangroves had declined significantly over the past two decades (1995-2016) making way for developed land (growth of Bagamoyo Town), cultivated land (agricultural expansion with increasing population) and grasslands (coastal habitat changes). Seasonal LULC changes were conversion of wetlands to cultivated land after the wet season, and transformation of fallow wetlands to grasslands. The estuarine fishery relied on a small number of mainly freshwater and marine migrant species, compared to a highly diverse mix of mainly marine species in the nearby coastal fishery. The sparsity of quantitative fisheries data, spectral confusion when modelling land-cover change, and absence of household survey data to assess livelihood activities remain major information gaps. Generalized recommendations for improving socio-ecological change studies in WIO estuarine systems are provided.

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Deusdado, Pedro, Magno Guedes, André Silva, Francisco Marques, Eduardo Pinto, Paulo Rodrigues, André Lourenço et al. "Sediment Sampling in Estuarine Mudflats with an Aerial-Ground Robotic Team". Sensors 16, n.º 9 (9 de setembro de 2016): 1461. http://dx.doi.org/10.3390/s16091461.

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Berthe, Thierry, Aurélie Touron, Julie Leloup, Julien Deloffre e Fabienne Petit. "Faecal-indicator bacteria and sedimentary processes in estuarine mudflats (Seine, France)". Marine Pollution Bulletin 57, n.º 1-5 (janeiro de 2008): 59–67. http://dx.doi.org/10.1016/j.marpolbul.2007.10.013.

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Sato, Masanori. "Anthropogenic decline of the peculiar fauna of estuarine mudflats in Japan". Plankton and Benthos Research 5, Supplement (2010): 202–13. http://dx.doi.org/10.3800/pbr.5.202.

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Wang, Fenfang, Zeyang Lu, Craig R. Tobias, Yao Wang, Kai Xiao, Qibiao Yu, Jingjie Lin, Guanmin Huang e Nengwang Chen. "Salt marsh expansion into estuarine mangrove mudflats reduces nitrogen removal capacity". CATENA 232 (novembro de 2023): 107459. http://dx.doi.org/10.1016/j.catena.2023.107459.

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Raffaelli, D., J. Limia, S. Hull e S. Pont. "Interactions Between the Amphipod Corophium Volutator and Macroalgal Mats on Estuarine Mudflats". Journal of the Marine Biological Association of the United Kingdom 71, n.º 4 (novembro de 1991): 899–908. http://dx.doi.org/10.1017/s0025315400053558.

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One of the most obvious effects of eutrophication in sheltered coastal areas and estuaries is enhanced growth of opportunistic macroalgae, which may form extensive mats over intertidal mudflats during the spring and summer. In the Ythan estuary, densities of the amphipod Corophium volutator (Pallas) in the sediment underlying weed mats were significantly lower than those in weed-free sediments, and are dominated by species characteristic of organically enriched, low oxygen environments such as Capitella capitata. Long-term data sets on Corophium abundance in the Ythan suggest that this species has declined dramatically throughout those parts of the estuary affected by weed mats.

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Manoylov, Kalina, Yenkang France, Abeselom Geletu e Joseph Dominy. "Algal Community Membership of Estuarine Mudflats from the Savannah River, United States". Journal of Marine Science and Engineering 4, n.º 1 (22 de fevereiro de 2016): 11. http://dx.doi.org/10.3390/jmse4010011.

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Shapiro, Karen, Patricia A. Conrad, Jonna A. K. Mazet, Wesley W. Wallender, Woutrina A. Miller e John L. Largier. "Effect of Estuarine Wetland Degradation on Transport of Toxoplasma gondii Surrogates from Land to Sea". Applied and Environmental Microbiology 76, n.º 20 (27 de agosto de 2010): 6821–28. http://dx.doi.org/10.1128/aem.01435-10.

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ABSTRACT The flux of terrestrially derived pathogens to coastal waters presents a significant health risk to marine wildlife, as well as to humans who utilize the nearshore for recreation and seafood harvest. Anthropogenic changes in natural habitats may result in increased transmission of zoonotic pathogens to coastal waters. The objective of our work was to evaluate how human-caused alterations of coastal landscapes in California affect the transport of Toxoplasma gondii to estuarine waters. Toxoplasma gondii is a protozoan parasite that is excreted in the feces of infected felids and is thought to reach coastal waters in contaminated runoff. This zoonotic pathogen causes waterborne toxoplasmosis in humans and is a significant cause of death in threatened California sea otters. Surrogate particles that mimic the behavior of T. gondii oocysts in water were released in transport studies to evaluate if the loss of estuarine wetlands is contributing to an increased flux of oocysts into coastal waters. Compared to vegetated sites, more surrogates were recovered from unvegetated mudflat habitats, which represent degraded wetlands. Specifically, in Elkhorn Slough, where a large proportion of otters are infected with T. gondii, erosion of 36% of vegetated wetlands to mudflats may increase the flux of oocysts by more than 2 orders of magnitude. Total degradation of wetlands may result in increased Toxoplasma transport of 6 orders of magnitude or more. Destruction of wetland habitats along central coastal California may thus facilitate pathogen pollution in coastal waters with detrimental health impacts to wildlife and humans.

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Moles, N. R., S. M. Betz, A. J. McCready e P. J. Murphy. "Replacement and authigenic mineralogy of metal contaminants in stream and estuarine sediments at Newtownards, Northern Ireland". Mineralogical Magazine 67, n.º 2 (abril de 2003): 305–24. http://dx.doi.org/10.1180/0026461036720103.

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Tidal mudflats are locally enriched in heavy metals at the head of Strangford Lough in Northern Ireland, where drainage from the hinterland enters the sea lough via a tidal canal in an urban area. To characterize the metallic contaminants and investigate their provenance, heavy particles separated from stream, canal and estuarine sediments were analysed by electron microprobe and laser Raman microspectroscopic methods. Potential metal sources are mineralization in the catchment area and industrial or domestic pollution. Anthropogenic particles include metallic grains, alloys and compounds of Pb, Zn, Cu, Fe, Cr and Sn. Alteration of metallic particles includes de-zincification of brass in freshwater sediment and replacement of Cu wire by covellite in brackish to marine sediment. Mobility of Cu, Fe and S in canal and estuarine sediments is indicated by the authigenic growth of framboidal Fe sulphide on oxide substrates and of chalcopyrite rims on covellite. Intricate colloform and platy crystalline textures suggest a cyclical deposition of covellite and chalcopyrite under conditions of varying redox and salinity. Lead and Cr mobility in the contaminated estuarine sediment is shown by the authigenic formation on Pb-rich substrates of heterogeneous Pb- and Cr-rich sulphate-phosphate compounds and Pb-oxychlorides.

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Murphy, RJ, TJ Tolhurst, MG Chapman e AJ Underwood. "Spatial variation of chlorophyll on estuarine mudflats determined by field-based remote sensing". Marine Ecology Progress Series 365 (18 de agosto de 2008): 45–55. http://dx.doi.org/10.3354/meps07456.

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Ravenscroft, N. O. M., e C. H. Beardall. "The importance of freshwater flows over estuarine mudflats for wintering waders and wildfowl". Biological Conservation 113, n.º 1 (setembro de 2003): 89–97. http://dx.doi.org/10.1016/s0006-3207(02)00352-x.

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Mazik, K., e M. Elliott. "The effects of chemical pollution on the bioturbation potential of estuarine intertidal mudflats". Helgoland Marine Research 54, n.º 2-3 (27 de julho de 2000): 99–109. http://dx.doi.org/10.1007/s101520050008.

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Jorissen, Frans J., Marie P. A. Fouet, David Singer e Hélène Howa. "The Marine Influence Index (MII): A Tool to Assess Estuarine Intertidal Mudflat Environments for the Purpose of Foraminiferal Biomonitoring". Water 14, n.º 4 (21 de fevereiro de 2022): 676. http://dx.doi.org/10.3390/w14040676.

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In this paper, we propose a marine influence index (MII), which is thought to give an integrated quantitative description of the complex of the environmental parameters controlling the foraminiferal fauna in estuarine intertidal mudflats. The MII contains three components, as follows: (1) the relative distance along the salinity gradient, (2) the emergence time relative to a reference tidal cycle, and (3) the relative importance of river outflow in the 30 days before sampling the foraminiferal fauna. Although these three parameters all have a strong relation with salinity, they also implicitly include other environmental parameters, such as the introduction of marine and continental organic matter and biota, hydrodynamic energy, or temperature. In order to show the functioning of this new index, MII is calculated for 28 stations in the Auray and Vie estuaries, for two different periods. The next step will be to compare the MII with faunal data sets. Ideally, this comparison should allow us to find strong correlations between some characteristics of the foraminiferal assemblages and the MII. If such strong correlations were indeed found, any major deviation of this relationship could then be interpreted as being due to strong anthropogenic disturbance.

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Manoylov, Kalina. "Benthic Diatom Motility in Estuarine Mudflats and Coastal Sands of the Atlantic Ocean Coast". International Journal of Marine Biology and Research 2, n.º 1 (3 de agosto de 2017): 1–9. http://dx.doi.org/10.15226/24754706/2/1/00112.

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Huang, Shou-Chung, Shang-Shu Shih, Yi-Shen Ho, Chang-Po Chen e Hwey-Lian Hsieh. "Restoration of Shorebird-Roosting Mudflats by Partial Removal of Estuarine Mangroves in Northern Taiwan". Restoration Ecology 20, n.º 1 (26 de outubro de 2010): 76–84. http://dx.doi.org/10.1111/j.1526-100x.2010.00744.x.

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Furaca, Noca B., Antonio M. Hoguane, Fiona Mackay, Marinel Willemse e Avelino A. Langa. "Exploring urbanization and critical habitat loss through land cover change around the Bons Sinais Estuary, Mozambique". Western Indian Ocean Journal of Marine Science, n.º 1/2021 (23 de dezembro de 2021): 43–58. http://dx.doi.org/10.4314/wiojms.si2021.1.4.

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Estuaries supply direct and indirect multi-sectoral opportunities including for transport, natural resource use and climate protection. These provisions support livelihoods and contribute to social and economic development. The Bons Sinais Estuary in Zambézia Province, central Mozambique, is adjacent to the provincial administrative capital Quelimane, some 25 km from the coast. The rapid growth of Quelimane has increased the demand for natural resources from the estuary, including space, food, fuelwood, transport and raw materials for construction and economic activities. Expansion of the built environment has extended into low-lying lands, mostly within the critical estuarine functional zone with inevitable consequences, such as damage to natural habitats and flooding of occupied areas during rainy seasons. The aim of this study was to analyse three decades of change (1991 – 2018) in land use and land cover (LU/LC) in the Bons Sinais Estuary, focussing on the growth of Quelimane city and the transformation of estuarine and surrounding habitats. The method relied on open-access satellite images and a LU/LC change analysis to quantify the spatio-temporal changes brought about by economic development and related human activities. A combination of low-intensity fieldwork and satellite-derived data (Landsat-5, sensor: Thematic Mapper and Landsat-8; sensors: Operational Land Imager, Thermal Infra-Red Scanner) was used to generate LU/LC information classified according to the features: mangrove trees; wetlands; estuary intertidal areas; built-up area; cultivated trees; and cultivated land. From 1991 onwards, there was an overall increase in cultivated crops (66 %), development (79 %) (including rural human settlements) and intertidal mudflats (12 %) with a concomitant decline in critical wetlands (16 %) and mangroves (12 %). The study predicts a worsening of the impacts on the estuarine ecosystem with further growth of Quelimane city. To reverse the negative trend on estuary health, the recommendation is for management interventions that promote sustainable LU, and urban development plans that consider ecosystem conservation and active restoration.

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Song, Ziming, Yingyue Sun, Peng Chen e Mingming Jia. "Assessing the Ecosystem Health of Coastal Wetland Vegetation (Suaeda salsa) Using the Pressure State Response Model, a Case of the Liao River Estuary in China". International Journal of Environmental Research and Public Health 19, n.º 1 (4 de janeiro de 2022): 546. http://dx.doi.org/10.3390/ijerph19010546.

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Suaeda salsa (S. salsa) is an important ecological barrier and tourism resource in coastal wetland resources, and assessing changes in its health is beneficial for protecting the ecological health of wetlands and increasing finances. The aim was to explore improvements in the degradation of S. salsa communities in the Liao River Estuary National Nature Reserve since a wetland restoration project was carried out in Panjin, Liaoning Province, China, in 2015. In this study, landscape changes in the reserve were assessed based on Sentinel-2 images classification results from 2016 to 2019. A pressure-state-response framework was constructed to assess the annual degradation of S. salsa communities within the wetlands. The assessment results show that the area of S. salsa communities and water bodies decreased annually from 2016 to 2019, and the increased degradation indicators indicate a state of continued degradation. The area of types such as aquaculture ponds and Phragmites australis communities did not change much, while the estuarine mudflats increased year by year. The causes of S. salsa community degradation include anthropogenic impacts from abandoned aquaculture ponds and sluice control systems but also natural impacts from changes in the tidal amplitude and soil properties of the mudflats. The results also indicate that the living conditions of S. salsa in the Liao River estuary wetlands are poor and that anthropogenic disturbance is necessary to restore the original vegetation abundance.

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HSU, JHIH-WEI, e HSI-TE SHIH. "First records of Parahelice K. Sakai, Türkay & Yang, 2006 and Pseudohelice K. Sakai, Türkay & Yang, 2006 from Vanuatu, with description of a new species of Parahelice (Crustacea: Brachyura: Varunidae)". Zootaxa 5476, n.º 1 (4 de julho de 2024): 138–51. http://dx.doi.org/10.11646/zootaxa.5476.1.14.

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The genera Parahelice K. Sakai, Türkay & Yang, 2006, and Pseudohelice K. Sakai, Türkay & Yang, 2006, are widely distributed in estuarine, mudflats, or mangroves in the Indo-West Pacific, and species of them are often sympatric. Species identification of the two genera is generally difficult, mainly due to the similar morphology and large intraspecific variation. Our study is the first report of the two genera from Vanuatu, including one new species, Parahelice ngankeeae sp. nov., as well as Par. pilimana (A. Milne-Edwards, 1873) and Pseudohelice subquadrata (Dana, 1851). These species can be distinguished from similar species by the characters of the suborbital cristae, the male chelipedal manus, and the first gonopods. The new species is also supported by the molecular results from the cytochrome c oxidase subunit I (COI).

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Bellinger, BJ, AS Abdullahi, MR Gretz e GJC Underwood. "Biofilm polymers: relationship between carbohydrate biopolymers from estuarine mudflats and unialgal cultures of benthic diatoms". Aquatic Microbial Ecology 38 (2005): 169–80. http://dx.doi.org/10.3354/ame038169.

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Hammond, Mark E. R., Gonzalo C. Malvarez e Alan Cooper. "The distribution of Spartina anglica on estuarine mudflats in relation to wave-related hydrodynamic parameters." Journal of Coastal Research 36 (março de 2002): 352–55. http://dx.doi.org/10.2112/1551-5036-36.sp1.352.

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Li, C., CE Reimers e JW Chapman. "Microbiome analyses and presence of cable bacteria in the burrow sediment of Upogebia pugettensis". Marine Ecology Progress Series 648 (27 de agosto de 2020): 79–94. http://dx.doi.org/10.3354/meps13421.

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We utilized methods of sediment cultivation, catalyzed reporter deposition-fluorescence in situ hybridization, scanning electron microscopy, and 16s rRNA gene sequencing to investigate the presence of novel filamentous cable bacteria (CB) in estuarine sediments bioturbated by the mud shrimp Upogebia pugettensis Dana and also to test for trophic connections between the shrimp, a commensal bivalve (Neaeromya rugifera), and the sediment. Agglutinated sediments from the linings of shrimp burrows exhibited higher abundances of CB compared to surrounding suboxic and anoxic sediments. Furthermore, CB abundance and activity increased in these sediments when they were incubated under oxygenated seawater. Through core microbiome analysis, we found that the microbiomes of the shrimp and bivalve shared 181 taxa with the sediment bacterial community, and that these shared taxa represented 17.9% of all reads. Therefore, bacterial biomass in the burrow sediment lining is likely a major food source for both the shrimp and the bivalve. The biogeochemical conditions created by shrimp burrows and other irrigators may help promote the growth of CB and select for other dominant members of the bacterial community, particularly a variety of members of the Proteobacteria. These associations give new understanding to the ecology of a burrowing crustacean that is common, but in decline, throughout intertidal mudflats of Northeastern Pacific estuaries.

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Kon, Koetsu, Prasert Tongnunui e Hisashi Kurokura. "Do allochthonous inputs represent an important food resource for benthic macrofaunal communities in tropical estuarine mudflats?" Food Webs 2 (março de 2015): 10–17. http://dx.doi.org/10.1016/j.fooweb.2015.03.001.

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Hogan, S., EAK Murphy, MP Volaric, MCN Castorani, P. Berg e MA Reidenbach. "Influence of oyster reefs on infauna and sediment spatial distributions within intertidal mudflats". Marine Ecology Progress Series 686 (24 de março de 2022): 91–106. http://dx.doi.org/10.3354/meps13983.

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Oysters are described as estuarine ecosystem engineers because their reef structures provide habitat for a variety of flora and fauna, alter hydrodynamics, and affect sediment composition. To what spatial extent oyster reefs influence surrounding infauna and sediment composition remains uncertain. We sampled sediment and infauna across 8 intertidal mudflats at distances up to 100 m from oyster reefs within coastal bays of Virginia, USA, to determine if distance from reefs and physical site characteristics (reef elevation, local hydrodynamics, and oyster cover) explain the spatial distributions of infauna and sediment. Total infauna density increased with distance away from reefs; however, the opposite was observed for predatory crustaceans (primarily crabs). Our results indicate a halo surrounding the reefs of approximately 40 m (using an increase in ~25% of observance as the halo criterion). At 90 m from reefs, bivalves and gastropods were 70% more likely to be found (probability of observance), while there was an approximate 4-fold decrease for large crustaceans compared to locations adjacent to reefs. Increases in percent oyster reef cover and/or mean reef area did not statistically alter infauna densities but showed a statistical correlation with smaller sediment grain size, increased organic matter, and reduced flow rates. Weaker flow conditions within the surrounding mudflats were also associated with smaller grain sizes and higher organic matter content, suggesting multiple drivers on the spatial distribution of sediment composition. This study emphasizes the complexity of bio-physical couplings and the considerable spatial extent over which oyster reefs engineer intertidal communities.

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Fouet, Marie, Maxime Daviray, Emmanuelle Geslin, Edouard Metzger e Frans Jorissen. "Foraminiferal test dissolution reveals severe sediment acidification in estuarine mudflats: new perspectives for present and historical assessment". Comptes Rendus. Géoscience 356, G1 (4 de julho de 2024): 83–96. http://dx.doi.org/10.5802/crgeos.269.

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Siciliano, Alfonso, David R. Schiel e Mads S. Thomsen. "Effects of local anthropogenic stressors on a habitat cascade in an estuarine seagrass system". Marine and Freshwater Research 70, n.º 8 (2019): 1129. http://dx.doi.org/10.1071/mf18414.

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Recent research has shown that co-occurring primary and secondary habitat-forming species typically support higher biodiversity than do monocultures of the primary habitat-former alone. However, these ‘habitat cascades’ may not be universal and it is important to know whether, when and where positive effects on biodiversity from secondary habitat-forming species change to negative effects. Here, we tested how anthropogenic stressors (fertilisation and sedimentation) and unattached secondary habitat-forming Ulva seaweeds affected the primary habitat-forming seagrass, Zostera muelleri, and its associated invertebrates in the Avon–Heathcote Estuary, New Zealand. We experimentally stressed Zostera by adding different fertilisation and sediment levels. Fertilisation had little impact, whereas even low sedimentation levels had strong negative effects on Zostera and its associated fauna. In a second experiment, sediments and Ulva were added to seagrass beds and unvegetated mudflats to test whether sediment stress modifies habitat cascades. We found again strong negative effects of sediments on Zostera, irrespective of spatio-temporal conditions, and that negative effects of sediments on invertebrates were enhanced in the presence of the secondary habitat former. These results highlighted that anthropogenic stressors can destabilise habitat cascades; processes that may be of particular importance in estuaries that are characterised by low biodiversity and stressful environmental conditions.

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Guedes, Éden Hávila Lima, Juan Alves Pereira, Gitá Juan Soterorudá Brito, Alexandre da Gama Fernandes Vieira Júnior e André Luiz Machado Pessanha. "Predation Risk, Foraging and Reproduction of an Insectivore Fish Species Associated with Two Estuarine Habitats". Diversity 16, n.º 11 (20 de novembro de 2024): 707. http://dx.doi.org/10.3390/d16110707.

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Pneumatophore fringes and mudflats are extremely valuable habitats and provide structures on which many fish species benefit in terms of food and reduced predation risk. We analyzed the spatiotemporal patterns in feeding habits, reproductive aspects and effects of predatory fish presence to assess the ecological drivers of the common halfbeak, Hyporhamphus unifasciatus, in a Brazilian estuary. Sampling was conducted during the rainy and dry periods. In summary, the results demonstrated that the number of predatory fishes was a strong predictor of population abundance and biomass, followed by pneumatophore complexity. The abundance and biomass values tended to increase with increasing habitat structural complexity towards the upper estuary. There was evidence that fish exhibited movement during the rainy season related to spawning events and subsequent juvenile recruitment in this area. Hymnoptera was the item most frequently ingested and made the greatest contributions to the volume of diet in habitat types throughout the year. There was an increase in the condition factor in the rainy season, which was associated with energy reserves, reproduction and growth (fitness). We concluded that predation is an important ecological process that operates at local spatial scales and that, together with the density of pneumatophores, it could affect the abundance of common halfbeak populations associated with estuarine habitats.

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Martinetto, Paulina, Pablo Ribeiro e Oscar Iribarne. "Changes in distribution and abundance of juvenile fishes in intertidal soft sediment areas dominated by the burrowing crab Chasmagnathus granulatus". Marine and Freshwater Research 58, n.º 2 (2007): 194. http://dx.doi.org/10.1071/mf06079.

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Intertidal estuarine areas located between southern Brazil and the northern Argentinean Patagonia are characterised by extended beds of the burrowing crab Chasmagnathus granulatus. Their activity leads to profound changes in the structure, quality and dynamics of sediments, which affect the entire benthic community and create a patchy distribution of resources for other species. In this study, the differences in habitat use by juvenile fishes above soft sediments inhabited by C. granulatus were evaluated. Adjacent areas with (‘crab beds’) and without crab burrows in intertidal mudflats of the Mar Chiquita Coastal Lagoon (37°32'S, 57°19'W) were sampled seasonally from 2000 to 2002. There were more fish species in crab-bed areas. Abundances of benthivorous and planktivorous fishes were also higher in crab beds during flood tide; however, during ebb tide, planktivorous fishes were more abundant outside crab-bed areas, whereas benthivores did not vary between areas. The present study demonstrated that species composition and abundance of juvenile fishes can be affected by the presence of bioturbator species such as C. granulatus.

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Dayaram, Anisha, Sharyn Goldstien, Peyman Zawar-Reza, Christopher Gomez, Jon S. Harding e Arvind Varsani. "Novel ssDNA virus recovered from estuarine Mollusc (Amphibola crenata) whose replication associated protein (Rep) shares similarities with Rep-like sequences of bacterial origin". Journal of General Virology 94, n.º 5 (1 de maio de 2013): 1104–10. http://dx.doi.org/10.1099/vir.0.050088-0.

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Over the past couple of years highly diverse novel ssDNA viruses have been discovered. Here, we present the first ssDNA virus, Gastropod-associated circular ssDNA virus (GaCSV), recovered from a mollusc Amphibola crenata Martyn 1784, which is a deposit feeder that grazes micro-organisms and organic detritus on the surface of tidal mudflats. The GaCSV (2351 nt) genome contains two large bidirectionally transcribed ORFs. The smaller ORF (874 nt) has similarities to viral replication-associated protein (Rep) sequences of some bacteria and circoviruses, whereas the larger ORF (955 nt) does not relate to any sequences in public databases and we presume it potentially encodes the capsid protein. Phylogenetic analysis shows that the GaCSV Rep clusters with Rep-like sequences of bacterial origin, highlighting the role of ssDNA viruses in horizontal gene transfer. The occurrence of previously unknown viruses in organisms associated with human pollution is a relatively unexplored field.

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Luglia, Mathieu, Stéven Criquet, Max Sarrazin e Daniel Guiral. "Extracellular enzyme activities of estuarine mudflats in French Guiana in relation with environmental factors across spatial and seasonal scales". Estuarine, Coastal and Shelf Science 225 (setembro de 2019): 106243. http://dx.doi.org/10.1016/j.ecss.2019.106243.

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Browne, Michael A. E. "The physical geography and geology of the estuary and Firth of Forth, Scotland". Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 93, n.º 3-4 (1987): 235–44. http://dx.doi.org/10.1017/s0269727000006709.

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SynopsisThe Upper Palaeozoic bedrock, which is of sedimentary and volcanic origin, is briefly described. The origin of the Forth as a series of depressions in the bedrock surface probably owes much to erosion of a pre-existing Tertiary landscape during phases of Quaternary glaciation. The late Quaternary history of the area is described, relating the distribution of the sediments deposited in the Forth to climatic events and changes in relative sea-level. Since the acme of the last main glaciation about 20,000 years ago, late Devensian marine and estuarine sediments have been deposited on the underlying glacial till sheet at altitudes ranging from more than 120 m below O.D. to at least 46 m above O.D. Similarly, raised and buried beaches and their deposits occur at altitudes from 40 m above O.D. down to around 10 m below O.D. in the estuary. During the Flandrian, sea-level has fluctuated, reaching its maximum (about 11 to 15 m above O.D.) about 6500 years ago. The typical deposit of this period is the carse clay which forms a series of extensive, fertile raised mudflats around the estuary. The calcareous marine faunas of the carse clay and older deposits are outlined.

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Gao, Yin, Lijuan Cui, Jianjun Liu, Wei Li e Yinru Lei. "China's coastal-wetland change analysis based on high-resolution remote sensing". Marine and Freshwater Research 71, n.º 9 (2020): 1161. http://dx.doi.org/10.1071/mf19062.

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Coastal wetlands not only have abundant biodiversity and high productivity, but they also play an irreplaceable and important role in regional ecosystems. Because of the complex structure and dynamic characteristics of coastal wetlands, it is difficult to observe the spatial changes of coastal wetlands on a large scale and improve data reliability. In this study, a spatially constrained manual-interpretation method based on nationwide high-resolution images in 2017 was adopted to extract China’s coastal wetland distribution, and, then, the second national wetland-survey data from 2011 were used as a baseline for change analysis. The results showed that under the influence of natural conditions and human activities, China’s coastal wetlands have decreased in distribution in the past 6 years. The situation of coastal wetland reclamation is critical, and the hotspot regions are mainly distributed in Bohai Bay, middle of Jiangsu province and Hangzhou Bay. Farming reclamation is another factor that occupies coastal wetlands in China, and main occupied wetlands are mudflats, shallow sea, tidal flats, intertidal salt marshes and estuarine waters. Tide is the main factor affecting extraction of wetlands, the spatially constrained method had a positive effect on wetland detection, and has potential to improve automatic algorithms of complex coastal wetlands.

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Payne, Nicholas Leslie, e Bronwyn May Gillanders. "Assemblages of fish along a mangrove - mudflat gradient in temperate Australia". Marine and Freshwater Research 60, n.º 1 (2009): 1. http://dx.doi.org/10.1071/mf08124.

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Mangroves are considered to support rich assemblages of fish and invertebrates. Fishes inhabiting mangrove habitats and at various distances from mangroves across mudflats were sampled to: (1) compare fish assemblages between habitats; and (2) determine the influence of mangrove proximity on fish abundance and diversity in three southern Australian estuaries between November 2005 and January 2006. Based on their distribution, fish species were classified as mangrove residents, mudflat residents, generalists or rare species. The assemblage structure of fish in mangroves differed from assemblages 500 m away; however, neither total abundance nor species richness differed significantly between mangroves and mudflats. Mangrove residents and Aldrichetta forsteri (yellow-eyed mullet) displayed strong associations with mangrove habitats, whereas mudflat residents were associated with mudflat habitats. No other fish groups or individual species occurred in higher abundances in either habitat. Total fish abundance, mangrove residents and A. forsteri were positively correlated with pneumatophore density, indicating that the structural complexity of the mangroves might influence the distributions of certain fish species. The current study demonstrated that mangrove habitats in temperate Australia support no greater abundance or diversity of fish than adjacent mudflat habitats and that mangrove proximity does not influence fish distribution at a habitat scale.

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Little, D. I., e A. E. Little. "Estuarine Oil Spill Effects in the Context of Dispersant use Changes". International Oil Spill Conference Proceedings 1991, n.º 1 (1 de março de 1991): 507–18. http://dx.doi.org/10.7901/2169-3358-1991-1-507.

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ABSTRACT Surveys of rock, cobble, gravel, and salt marsh shores, intertidal macrobenthos, hydrocarbons, and estuarine bird populations were carried out over twelve months following the El Omar spill of 3 December 1988, when 100 metric tons (t) of Iranian light crude oil were spilled in Milford Haven, United Kingdom. Although small, this incident resulted in more widespread shoreline oiling than any previous spill in 30 years of operations at Milford Haven. About 20 t of chemical dispersant were used in the lower estuary. Dispersants were not used where there was a danger of oil and dispersant mixtures impinging on fish farms. Rock/cobble shores have been studied since the arrival of the oil industry in 1960 and spill impacts were, therefore, discernible at some sites against the baseline data. Serious impacts occurred locally due to excessive oiled algae and substrate removal. On gravel and salt marsh study sites, natural removal of oil was an efficient cleanup option. Some evidence was detected, however, that oil deposited on seed heads of Spartina was later transferred to the sediment surface as part of the litter fall. The marsh vegetation recovered by the end of the 1989 growing season, confirming the resilience of this community to single oil spills, provided intrusive cleanup is not attempted. The increase in aromatic hydrocarbon concentrations found in the surface sediments of the salt marsh was found also in mudflats adjacent to heavily-oiled areas, although no biological effects on the infauna of the inner estuary were detected (compared to a macrobenthic and hydrocarbon survey of 1984). No significant impacts were recorded on the population of 20,000 waders, wildfowl, and gulls present at the time of the spill. This is believed to be partly fortuitous due to the mild 1988/89 winter. The arrival in Milford Haven of intensive fish farming means that the previously routine use of chemical dispersants in the oil port will now be increasingly challenged. From the El Omar, it may be predicted that, in future spills, more oil will become stranded in marshes and rock and cobble shorelines. Not only are guidelines and scientific advice during shoreline cleanup essential, but also it is recommended that scientific monitoring, which lapsed in the early 1980s, be reinstated. These data would help make the important tradeoff between commercial and conservation interests in future spills.

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Lanari, Marianna, Bianca Possamai, Margareth Copertino e Alexandre Miranda Garcia. "Dataset on the isotopic (ẟ13C, ẟ15N) and elemental (C, N) composition of estuarine primary producers in the subtropical Southwestern Atlantic coast". Latin American Data in Science 1, n.º 1 (26 de julho de 2021): 8–15. http://dx.doi.org/10.53805/lads.v1i1.10.

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Benthic and pelagic primary producers had their isotopic (ẟ13C, ẟ15N) and elemental (C, N) composition monitored in the Patos Lagoons estuary, in southern Brazil. The present dataset comprises temporal data obtained through seasonal samplings of C3 (Scirpus spp.) and C4 (Spartina densiflora) salt marsh plants, ephemerous bloom-forming drift macroalgae (Ulvophyceae), the widgeon grass Ruppia maritima, particulate (POM) and sedimentary (SOM) organic matter in shallow waters (< 2m) of a subtropical estuary from austral summer 2010 to autumn 2016. POM and SOM were collected as proxies of phytoplankton and microphytobenthos, respectively. Salt marsh plants were randomly sampled (N = 126) at a regularly flooded low marsh area, whereas submerged drift macroalgae (N = 29) and Ruppia plants (N = 14) were collected in adjacent mudflats. POM was collected (N = 33) by filtering water samples using glass fiber filter. SOM was obtained (N = 35) by removing superficial sediment. In laboratory, samples were processed and further analyzed for total organic carbon (TOC), total nitrogen (TN) and carbon (13C/12C) and nitrogen (15N/14N) stable isotopes ratios. With a total of 237 samples analyzed, this dataset provides key information on the isotopic and elemental composition of distinct estuarine primary producers and sources of particulate organic matter (POM and SOM) and their temporal variability in a highly variable aquatic environment. Such knowledge may add to ecological studies investigating food webs, biogeochemical cycles and sources tracking in coastal systems.

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Cereja, Rui, Paula Chainho, Vanda Brotas, Joana P. C. Cruz, Giulia Sent, Marta Rodrigues, Frederico Carvalho, Sara Cabral e Ana C. Brito. "Spatial Variability of Physicochemical Parameters and Phytoplankton at the Tagus Estuary (Portugal)". Sustainability 14, n.º 20 (17 de outubro de 2022): 13324. http://dx.doi.org/10.3390/su142013324.

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The estuarine phytoplankton communities are known to respond rapidly to environmental changes, being considered an important water quality indicator; thus, it is crucial to fully understand its natural variability. The objective of the present study was to assess the spatial variability of both physicochemical variables and the phytoplankton community, to understand how such variability is influenced by seasonality and to evaluate how the anthropogenic sources affect such patterns. The Tagus estuary was used as a case study, since it is one of Europe’s largest estuaries, with high spatial and seasonal variations and a high level of human pressure associated with large urban and industrial areas. To achieve this goal, environmental parameters, nutrients concentration, bivalve biomass (filter feeders) and phytoplankton pigments were quantified in a single summer sampling campaign with high spatial resolution and in monthly campaigns in eight sampling stations through the Tagus estuary, in one year. In general, suspended particulate matter and nutrients decreased from the upper part of the estuary to the estuary mouth; however, relevant local inputs were also observed in more downstream locations, near outfalls of wastewater treatment plants (WWTP). The chlorophyll-a concentrations were higher over the southern intertidal mudflats, probably due to resuspension of microphytobenthos, associated with higher nutrient concentrations. Through a grazing indicator, it was observed that grazers are important drivers of variability of the phytoplankton community composition. All water bodies achieved “good” and “high” water quality classifications for both physicochemical and biological indicators, with the worst results reported for the water bodies located at the upper estuary. Therefore, this estuary presents a decreasing trend of nutrients and chlorophyll-a in the upstream–downstream direction, except for the estuary channels and the outfall in the northern margin, which lead to an increase in nutrient concentrations. However, these increases did not affect the water quality of the three analyzed water bodies, presenting at least good ecological status, considering the nutrient and chlorophyll-a indicators.

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Sigana, Dorcus Auma. "Diversity of Fishery Organisms and Their Contribution to The Community Sustainability of Kilifi Creek, Kenya". African Journal of Climate Change and Resource Sustainability 1, n.º 1 (17 de dezembro de 2022): 90–106. http://dx.doi.org/10.37284/ajccrs.1.1.1011.

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Fishery organisms are a source of food and income in local societies surrounding any water body. Investigations were carried out to study the diversity and distribution of fishery organisms of the Kilifi estuarine creek and their contribution to community sustainability. Sampling took place at Sea horse, Fumbini, Konjora, and Rare on the northern arm and at Nkoma, Mazioni, Fumbini, and Kombeni on the southern arm of the creek. All fishery organisms obtained were identified, counted and length dimensions taken. The 1444 prawns obtained were Fenneropenaeus indicus and Penaeus monodon while the 207 were four crab species Portunus armatus, Portunus sanguinolentus, Scylla serrata, and Thalamita crenata. F. indicus was the most abundant of the prawn species whereas P. armatus and S. serrata were caught at all study sites in smaller class sizes. 7,258 finfishes identified were 85 species belonging to 14 orders, 46 families. Biodiversity indices analysed showed that Margalef’s species richness index was highest (8.293) at Sea horse and lowest (3.874) at Rare. Pielou’s evenness was highest (0.7286) at Nkoma and lowest (0.5319) at Rare. Simpson’s diversity index was highest at Nkoma (0.8917) and lowest at Rare (0.6672). Bray-Curtis similarity grouped all fishes into three ecosystems, open sea waters, the mudflats, and river channels. The most abundant finfish species were Leiognathus equula (20.17 %) followed by Mugil cephalus (17.64%), Gerres filamentosus (10.25%), and Pomadasys multimaculatum (7.37%). Most abundant finfish species and crustaceans were in small class sizes hence for local consumption by communities around the creek

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Zhu, Yunyang, Linlin Lu, Zilu Li, Shiqing Wang, Yu Yao, Wenjin Wu, Rajiv Pandey, Aqil Tariq, Ke Luo e Qingting Li. "Monitoring Land Use Changes in the Yellow River Delta Using Multi-Temporal Remote Sensing Data and Machine Learning from 2000 to 2020". Remote Sensing 16, n.º 11 (28 de maio de 2024): 1946. http://dx.doi.org/10.3390/rs16111946.

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The Yellow River Delta (YRD), known for its vast and diverse wetland ecosystem, is the largest estuarine delta in China. However, human activities and climate change have significantly degraded the wetland ecosystem in recent decades in the YRD. Therefore, an understanding of the land use modifications is essential for the efficient management and preservation of ecosystems in this region. This study utilized time series of remote sensing data and the extreme gradient boosting method to generate land use maps of the YRD from 2000 to 2020. Several methods, including transition matrix, land use dynamic degree, and standard deviation ellipse, were employed to explore the characteristics of land use transitions. The results underscore significant spatial variations in land use over the past two decades. The most rapid increase was observed in built-up area, followed by terrestrial water and tidal flats, while unutilized land experienced the fastest decrease, followed by forest–grassland. The spatial distribution patterns of agricultural land, built-up area, terrestrial water, and forest–grassland demonstrated stronger directionality compared to other land use types. The wetlands have expanded in size and improved in structure. Unutilized land has been converted into artificial wetlands comprising ponds, reservoirs, salt ponds, shrimp and crab ponds, and natural wetlands featuring mudflats and forest–grassland. The wetland conservation efforts after 2008 have proven very effective, playing a positive role in ecological and environmental preservation, as well as in regional sustainable development.

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Galois, R., G. Blanchard, M. Seguignes, V. Huet e L. Joassard. "Spatial distribution of sediment particulate organic matter on two estuarine intertidal mudflats: a comparison between Marennes-Oléron Bay (France) and the Humber Estuary (UK)". Continental Shelf Research 20, n.º 10-11 (julho de 2000): 1199–217. http://dx.doi.org/10.1016/s0278-4343(00)00019-4.

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Li, Luofan, Xinju Li, Beibei Niu e Zixuan Zhang. "A Study on the Dynamics of Landscape Patterns in the Yellow River Delta Region". Water 15, n.º 4 (20 de fevereiro de 2023): 819. http://dx.doi.org/10.3390/w15040819.

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The Yellow River Delta region is one of the estuarine deltas with the fastest land building speed, and it is an important region for the study of landscape pattern change due to its diverse variety of landscape types. By analyzing the dynamic degree, landscape type transfer matrix, and landscape indices of landscape types in the Yellow River Delta region in 2005, 2012, and 2018, this paper found that the area of construction land, salt fields, and breeding ponds in the Yellow River Delta region has increased to a large extent, with an increase in the aggregation degree and the utilization rate of this landscape type, and the landscape has developed toward the direction of aggregation and unification. The increase in construction land area mainly comes from the transfer of cropland area, part of which is occupied in order to adapt to urban expansion, and the salt fields and breeding ponds mainly come from the transfer of waters and mudflats, which can be seen as the main utilization direction of the water landscape. Moreover, unused land has increased with the degree of dispersion and fragmentation of development and utilization, so the exploitation and utilization of unused land still needs to be optimized. Through the analysis of the dynamic change in landscape pattern, we can explore the direction and extent of the evolution of landscape types, which has certain guiding significance for the sustainable use of land resources and the sustainable development of economy in the Yellow River Delta region.

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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, n.º 2 (31 de dezembro de 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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Takiyama, Tomo, Sawako Hamasaki e Masayuki Yoshida. "Comparison of the Visual Capabilities of an Amphibious and an Aquatic Goby That Inhabit Tidal Mudflats". Brain, Behavior and Evolution 87, n.º 1 (2016): 39–50. http://dx.doi.org/10.1159/000443923.

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The mudskipper Periophthalmus modestus and the yellowfin goby Acanthogobius flavimanus are gobiid teleosts that both inhabit the intertidal mudflats in estuaries. While P. modestus has an amphibious lifestyle and forages on the exposed mudflat during low tide, the aquatic A. flavimanus can be found at the same mudflat at high tide. This study primarily aimed to elucidate the differential adaptations of these organisms to their respective habitats by comparing visual capacities and motor control in orienting behavior during prey capture. Analyses of retinal ganglion cell topography demonstrated that both species possess an area in the dorsotemporal region of the retina, indicating high acuity in the lower frontal visual field. Additionally, P. modestus has a minor area in the nasal portion of the retina near the optic disc. The horizontally extended specialized area in P. modestus possibly reflects the need for optimized horizontal sight on the exposed mudflat. Behavioral experiments to determine postural and eye direction control when orienting toward the object of interest revealed that these species direct their visual axes to the target situated below eye level just before a rapid approach toward it. A characteristic feature of the orienting behavior of P. modestus was that they aimed at the target by using the specialized retinal area by rotating the eye and lifting the head before jumping to attack the target located above eye level. This behavior could be an adaptation to a terrestrial feeding habitat in which buoyancy is irrelevant. This study provides insights into the adaptive mechanisms of gobiid species and the evolutionary changes enabling them to forage on land.

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Rosa, Leonardo Cruz, e Carlos Emilio Bemvenuti. "Effects of the burrowing crab Chasmagnathus granulata (Dana) on meiofauna of estuarine intertidal habitats of Patos Lagoon, Southern Brazil". Brazilian Archives of Biology and Technology 48, n.º 2 (março de 2005): 267–74. http://dx.doi.org/10.1590/s1516-89132005000200014.

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This study aimed to evaluate the effects of the burrowing crab Chasmagnathus granulata on meiofauna at three intertidal habitats across a tidal exposure gradient (i.e., an emerged salt marsh, an emerged mudflat and a submerged mudflat) in an estuarine embayment of Patos Lagoon, Southern Brazil. Meiofauna community was dominated by nematodes and ostracods, following by copepods and turbellarians. Densities of all studied organisms varied significantly among habitats. Highest values were observed in submerged mudflat while lower in salt marsh. Nematodes were unaffected by crab in either habitat, whereas ostracod, copepod and turbellarian densities were significantly lower in disturbed than control areas in both mudflat habitats. Any meiofaunal group was affected in salt marsh, probably due to a less intense disturbance. The results showed that the burrowing crab C. granulata could play an important role on meiofauna community structure in estuarine intertidal habitats of Patos Lagoon, because crab disturbance seemed to affect mainly surface populations, especially in mudflat. However, the meiofauna response to crab disturbance was variable among habitats depending of the intensity and the frequency of the disturbance.

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BRÜCKNER, MURIEL Z. M., WILLIAM J. MCMAHON e MAARTEN G. KLEINHANS. "MUDDYING THE WATERS: MODELING THE EFFECTS OF EARLY LAND PLANTS IN PALEOZOIC ESTUARIES". PALAIOS 36, n.º 5 (31 de maio de 2021): 173–81. http://dx.doi.org/10.2110/palo.2020.073.

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ABSTRACT The Paleozoic evolution of vegetation transformed terrestrial landscapes, facilitating novel sedimentary processes and creating new habitats. This transformation left a permanent mark on the sedimentary record, perhaps most strikingly via an upsurge in preserved terrestrial mudrock. Whereas feedbacks between evolving vegetation and river structure have been widely studied, Paleozoic estuaries have so far received scant attention. Located at the interface between the land and sea, the co-adjustment of estuarine morphology and plant traits are fundamentally tied to a varied range of geochemical cycles, and determine how global silicate weathering patterns may have varied over time. Here we employ an eco-morphodynamic model with an in-built vegetation code to simulate estuarine morphology through five key stages in plant evolution. An abiotic model (early Precambrian?) saw mud deposition restricted to fortuitous instances of limited erosion along bar-flanks. Estuaries colonized by microbial mats (Precambrian onwards) facilitated mud accretion that sufficiently stabilized bar surfaces to promote extensive mudflat development. Small-stature, rootless vegetation (Silurian–Early Devonian) introduced novel above-ground baffling effects which led to notable mud accumulation in lower-energy environments. The incorporation of roots (Early Devonian) strengthened these trends, with root structures decreasing the mortality of the occupying plants. Once the full complement of modern vascular plant architectures had evolved (Middle Devonian), dense colonization promoted the formation of in-channel islands accompanied with system-wide mud accumulation. These simulations suggest estuaries underwent profound change during the Paleozoic, with the greening of the continents triggering processes and feedbacks which render all previous source-to-sink sediment pathways non-uniformitarian.

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