Journal articles on the topic 'Estuaries'
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1
Shin, Hyun-Jung, Guan-hong Lee, KiRyong Kang, and Kyeong Park. "Shift of estuarine type in altered estuaries." Anthropocene Coasts 2, no. 1 (January 1, 2019): 145–70. http://dx.doi.org/10.1139/anc-2018-0013.
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To better understand the alteration of the estuarine circulation caused by estuarine dams, four major Korean estuaries were classified by using the Hansen and Rattray stratification–circulation classification scheme. The stratification and circulation parameters were calculated for both discharge and no-discharge periods from the tidally averaged salinity and velocity data obtained from these four Korean estuaries. The estuarine types of the altered Korean estuaries were compared with the previous results for natural estuaries in other countries of similar magnitude in tidal range, water depth, and discharge. This comparison revealed that the estuarine types of the altered Korean estuaries have been shifted from a partially mixed to a well-mixed type (Nakdong River Estuary), from a partially mixed to a coastal bay or a fjord type (Yeongsan River Estuary), and from a well-mixed to a well-mixed type with less tidal modulation (Geum River Estuary). The controlling factors that determined the type in natural estuaries were tide, discharge, and water depth, whereas for altered estuaries, they were the controlled river discharge and water depth. The different estuarine dam gate types with their different modes of operation (surface or bottom discharge) played an important role in the mixing and circulation of the altered estuaries.
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Ketchum, Bostwick H. "CIRCULATION IN ESTUARIES." Coastal Engineering Proceedings 1, no. 3 (January 1, 2000): 6. http://dx.doi.org/10.9753/icce.v3.6.
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In discussing the circulation in estuaries, an apparent paradox must always be kept in mind. In the first place the problems of estuarine circulation are unique, being different from the problems of the open sea, and from the problems of river hydrology. Estuarine circulation and related problems consequently constitute a valid field for investigation. In contrast to this viewpoint is the tremendous range of conditions found in various estuaries - no two are alike. This inherent variability of estuaries discourages generalizations about the circulation.
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Gillanders, Bronwyn M., Travis S. Elsdon, Ian A. Halliday, Gregory P. Jenkins, Julie B. Robins, and Fiona J. Valesini. "Potential effects of climate change on Australian estuaries and fish utilising estuaries: a review." Marine and Freshwater Research 62, no. 9 (2011): 1115. http://dx.doi.org/10.1071/mf11047.
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Estuaries are especially vulnerable to the impacts of climate change because changes in climatic and hydrologic variables that influence freshwater and marine systems will also affect estuaries. We review potential impacts of climate change on Australian estuaries and their fish. Geographic differences are likely because southern Australian climates are predicted to become warmer and drier, whereas northern regions may see increased precipitation. Environmental factors, including salinity gradients, suspended sediment, dissolved oxygen and nutrient concentrations, will be influenced by changing freshwater input and other climate variables. Potential impacts will vary depending on the geomorphology of the estuary and the level of build-up of sand bars across estuarine entrances. Changes to estuarine fish assemblages will depend on associated changes to salinity and estuarine-mouth morphology. Marine migrants may be severely affected by closure of estuarine mouths, depending on whether species ‘must’ use estuarine habitat and the level of migratory v. resident individuals. Depending on how fish in coastal waters locate estuaries, there may be reduced cues associated with estuarine mouths, particularly in southern Australia, potentially influencing abundance. In summary, climate change is expected to have major consequences for Australian estuaries and associated fish, although the nature of impacts will show significant regional variation.
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Groeneveld, Johan C., Antonio M. Hoguane, Baraka Kuguru, Fiona Mackay, Cosmas Munga, and Jorge Santos. "Estuarize-WIO: A socio-ecological assessment of small-scale fisheries in estuaries of the Western Indian Ocean." Western Indian Ocean Journal of Marine Science, no. 1/2021 (December 23, 2021): 1–15. http://dx.doi.org/10.4314/wiojms.si2021.1.1.
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Estuaries provide unique ecosystem goods and services and have been focal points for human settlement andresource use throughout recorded history. In the Western Indian Ocean (WIO) region, the effects of human population growth, rapid economic development and climate change on estuaries threaten their ecological functioning and the sustainability of estuary-dependent livelihoods. Governance systems are ill-equipped to deal with the mounting challenges. Long-term datasets that describe estuary-scale trends are scarce, and socio-ecological interactions that support sustainable use of resources are incompletely understood. To address these gaps, the Estuarize-WIO project (2016-2019) compiled datasets on biophysical, ecological, socio-economic and fisheries aspects of selected estuaries in Mozambique (Bons Sinais), Tanzania (Ruvu) and Kenya (Tana), analysed trends per estuary, and used a socio-ecological systems (SES) framework to integrate information from multiple sources at local and regional levels. The introductory paper of this Special Issue of the Western Indian Ocean Journal of Marine Science provides regional context and reviews the relevant literature available for WIO estuaries. In succeeding papers, estuarine circulation is inferred from hydrological measurements, seasonal and decadal trends in land cover and land use are investigated using remote sensing images, household surveys are used to investigate socio-economic circumstances and resource use, and long-term catch survey data and field samples are used to describe small-scale fisheries. In the synthesis paper, a SES framework is constructed to investigate linkages and feedback loops in individual estuaries. A regionally comparative analysis across the WIO region was conducted, and recommendations were made for future research and governance. The methodological approach developed for Estuarize-WIO is well-suited to research of data poor systems with limited accessibility and research infrastructure.
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Taddese, Fasil, Marc Schallenberg, Pavel Mikheev, Matt G. Jarvis, and Gerard P. Closs. "Ichthyofaunal assemblages in shallow littoral habitats of permanently open estuaries and intermittently closed and open lakes or lagoons in Otago, New Zealand." Marine and Freshwater Research 69, no. 8 (2018): 1222. http://dx.doi.org/10.1071/mf17334.
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Fish assemblages of New Zealand estuaries are poorly studied, and knowledge of the effects of estuary–ocean connections on the ichthyofaunal composition of estuaries remains limited. Understanding the status of fish composition of estuaries is crucial for planning for sustainable management of aquatic ecosystems. In the present study we sampled fish using a seine net from lower reaches of six permanently open estuaries and six intermittently closed and open lakes or lagoons (ICOLLs) along the Otago coastline during winter 2016 and summer 2017. Marked differences in ichthyofaunal composition were observed in the shallow littoral habitats of permanently open estuaries and ICOLLs. Fish assemblages reflected estuary–ocean connection status of estuaries during both seasons. ICOLLs showed greater fish abundance than permanently open systems. Fish abundance was higher in summer than in winter in both estuary types. Fish species with marine–estuarine opportunist and estuarine–migrant life histories dominated permanently open estuaries. Conversely, species with a diadromous life history but known to form landlocked populations were abundant in ICOLLs. Salinity and temperature were correlated with fish abundance in both estuary types.
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Slinger, J. H., and C. M. Breen. "Integrated research into estuarine management." Water Science and Technology 32, no. 5-6 (September 1, 1995): 79–86. http://dx.doi.org/10.2166/wst.1995.0566.
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Estuaries are under increasing pressure owing to agricultural, urban and industrial developments in their catchments and their status as favoured sites for coastal development and recreation. Effective research on South Africa estuaries requires the synthesis of available scientific knowledge to efficiently address management concerns and so ensure the sustainable utilisation of estuaries. The approach of the Consortium for Estuarine Research and Management to these problems and the results of a co-ordinated research programme on decision support for the management and conservation of estuarine systems are described in this paper. While the importance and current status of South African estuaries are considered, attention is devoted primarily to the development of an integrated modelling approach to the freshwater requirements of estuaries. In particular, the application of a linked system of five models to a case study, the Great Brak Estuary is described and the role of prediction in promoting wise decision making for estuaries is treated.
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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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Veldkornet, D. A., J. B. Adams, J. S. Boatwright, and A. Rajkaran. "Barcoding of estuarine macrophytes and phylogenetic diversity of estuaries along the South African coastline." Genome 62, no. 9 (September 2019): 585–95. http://dx.doi.org/10.1139/gen-2018-0067.
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Plant DNA barcoding serves as an effective approach to building community phylogenies and increasing our understanding of the factors that determine plant community assemblages. The aims of the study were to (i) barcode macrophytes with high estuarine fidelity and (ii) to determine the phylogenetic diversity (PD) of selected South African estuaries for conservation prioritisation. Three DNA barcoding gene regions (rbcLa, matK, and trnH-psbA) were assessed, and community phylogenies were constructed for 270 estuaries. Generally, the matK barcode had the greatest discrimination success rate of 67.4% (parsimony informative sites = 418). Closely related species formed clades that also represent estuarine habitat types. Estuaries with high phylogenetic diversity along the southeast coast were associated with a combination of mangrove and salt marsh habitats. Species richness was strongly and significantly correlated with PD (r = 0.93; p < 0.000). Based on mean pairwise distance (MPD), more temperate estuaries (56) showed significant phylogenetic clustering compared to subtropical estuaries (24) (p < 0.05). Similarly, based on mean nearest taxon distance (MNTD), significant phylogenetic clustering was highest in temperate estuaries (50) compared to subtropical estuaries (12) (p < 0.05). This suggests that the coexistence of plant species in estuaries is structured by both biotic and abiotic interactions.
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Kisten, Yanasivan, Nadine A. Strydom, Renzo Perissinotto, and Sourav Paul. "Modelling the occurrence of postflexion stages of a marine estuarine-dependent fish in temperate South African estuaries." Scientia Marina 81, no. 1 (March 27, 2017): 27. http://dx.doi.org/10.3989/scimar.04521.05a.
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The movement of postflexion larvae of marine estuarine-dependent species into estuaries is critical for the survival of fishes reliant on estuaries as nurseries. However, detailed studies focused on environmental variability experienced by postflexion larvae entering a range of estuary types under varying conditions are rare. This study assessed the in situ conditions (temperature, salinity and water clarity) under which the southern African endemic fish Rhabdosargus holubi (Sparidae) recruits into estuaries. Postflexion larvae were sampled in three biogeographic regions (cool temperate, warm temperate and subtropical boundary), which included three estuary types (permanently open estuaries (POEs), temporarily open/closed estuaries and estuarine lake systems) on a seasonal basis, independent of each other. Rhabdosargus holubi larvae were more abundant in spring and summer, in POEs in the warm temperate region. Models predicted that higher larval occurrence in estuaries is a function of lower salinity (e.g. mesohaline zones of 5-17.9 salinity) and lower water clarity (e.g. 0-0.2 Kd, light extinction coefficient), particularly for warm, temperate POEs. This re-emphasizes the importance of freshwater for optimal nursery functioning, which may be compromised by impoundments, abstraction and climate change in water-short countries like South Africa.
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Kim, Jun-Wan, Kyu-Jin Kim, Beom-Myeong Choi, Kyung-Lak Lee, Min-Ho Jang, and Ju-Duk Yoon. "The Application of a Fish-Based Multi-Metric Index for the Assessment of Ecological Qualities of Estuaries in the Korean Peninsula." Sustainability 14, no. 18 (September 15, 2022): 11608. http://dx.doi.org/10.3390/su141811608.
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Brackish water zones are areas with high ecological conservation value. In this study, 325 river estuaries in the Korean peninsula in individual sea areas (West Sea, South Sea, and East Sea) were divided into types of estuaries (upstream and downstream of open estuaries, closed estuaries) through the assessment of the health of the estuary aquatic ecosystems and fish communities were identified. An ecological assessment was carried out using the Korea Estuary Fish Assessment Index (KEFAI). The number of species increased as the size of the river increased in the case of small estuaries but gradually decreased in the case of large estuaries. In the closed estuaries, the relative abundances (RAs) of primary freshwater fish were the highest; however, in the open estuaries, the RAs of estuary fish were the highest. Non-metric dimensional analysis results suggested that there was a clear difference between the fish assemblages in the closed and open estuaries. The overall results of this study were that the RA of tolerant species was higher, and KEFAI was lower in closed estuaries than in open estuaries, indicating the negative effects of the construction of transverse structures on fish assemblages. The health of these estuarine ecosystems can be improved by addressing these negative effects.
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Barabanshchikov, E. I., and S. G. Bolshakov. "ESTUARINE-COASTAL SYSTEMS – THE TRANSITIVE ZONE BETWEEN FRESHWATER AND SEA ECOSYSTEMS." Vladimir Ya. Levanidov’s Biennial Memorial Meetings 10 (June 21, 2023): 16–25. http://dx.doi.org/10.25221/levanidov.10.02.
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The typifi cation of estuaries and the division of estuary zones of the rivers of Primorsky Territory are considered. Based on the collected data on aquatic biota and the orography of water bodies, three main types of estuaries in Primorye were identifi ed – lowland rivers with an extended estuary zone (Razdolnaya, Tumannaya and Artemovka rivers), mountain rivers with an extended estuarine zone (Kievka, Avvakumovka, Partizanskaya, Milogradovka, Margaritovka and other rivers), mountain rivers with a short estuarine zone (Zerkalnaya, Sukhodol, Barabashevka, Narva, Ryazanovka and other rivers). Characteristics are given on the basis of which the boundaries of estuaries are distinguished. The defi nition of the estuary zone is given.
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Gomes, Vando J. C., Nils E. Asp, Eduardo Siegle, José Diego Gomes, Ariane M. M. Silva, Andrea S. Ogston, and Charles A. Nittrouer. "Suspended-Sediment Distribution Patterns in Tide-Dominated Estuaries on the Eastern Amazon Coast: Geomorphic Controls of Turbidity-Maxima Formation." Water 13, no. 11 (June 1, 2021): 1568. http://dx.doi.org/10.3390/w13111568.
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In tide-dominated estuaries, maximum-turbidity zones (MTZs) are common and prominent features, characterized by a peak in suspended-sediment concentration (SSC) associated with estuarine processes. The Brazilian Amazon coast includes many estuaries, experiencing macrotidal conditions. MTZs are expected to occur and are crucial for sediment delivery to the longest continuous mangrove belt of the world. The area is under influence of the Amazon River plume (ARP), the main SSC source, as local rivers do not deliver substantial sediment supply. To assess the processes that allow the ARP to supply sediment to the estuaries and mangrove belt along the Amazon coast, the results from previous individual studies within five Amazon estuaries (Mocajuba, Taperaçu, Caeté, Urumajó and Gurupi) were compared with regards to SSC, salinity, morphology and tidal propagation. This comparison reinforces that these estuaries are subject to similar regional climate and tidal variations, but that their dynamics differ in terms of distance from the Amazon River mouth, importance of the local river sediment source, and morphology of the estuarine setting. The Urumajó, Caeté and Gurupi are hypersynchronous estuaries where perennial, classic MTZs are observed with SSC > 1 g·L−1. This type of estuary results in transport convergence and MTZ formation, which are suggested to be the main processes promoting mud accumulation in the Amazonian estuaries and therefore the main means of mud entrapment in the mangrove belt. The Mocajuba and the Taperaçu estuaries showed synchronous and hyposynchronous processes, respectively, and do not present classic MTZs. In these cases, the proximity to the ARP for the Mocajuba and highly connected tidal channels for the Taperaçu estuary, assure substantial mud supply into these estuaries. This study shows the strong dependence of the estuaries and mangrove belt on sediment supply from the ARP, helping to understand the fate of Amazon River sediments and providing insights into the mechanisms providing sediment to estuaries and mangroves around the world, especially under the influence of big rivers.
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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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Gallop, Shari L., Karin R. Bryan, David P. Hamilton, Melissa Foley, and John L. Largier. "ECOENGINEERING FRESHWATER FLOWS FOR ESTUARY HYDROLOGICAL STATE." Coastal Engineering Proceedings, no. 37 (September 1, 2023): 17. http://dx.doi.org/10.9753/icce.v37.management.17.
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The quantity, quality and timing of freshwater inflow into estuaries is critical to support estuarine ecosystem health. However, most estuaries are affected by upstream manipulation of freshwater inflows. Coinciding with the United Nations Decade of Restoration (2021–2030), there is great interest in re-creating functional estuarine ecosystems, including by modifying the physio-chemical characteristics with the premise that a functional ecosystem will follow (ecoengineering). To restore estuarine ecology, the physical processes of the system must first be conductive to supporting the re-establishment and sustenance of biota. These physical processes are generally under-monitored and often not used as a measure of restoration success. We explore ecoengineering to restore freshwater inflows to estuaries, focused on hydrological state. We use the Pressure—State—Response (PSR) framework to set the context for this review.
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Wei, Xi, Josette Garnier, Vincent Thieu, Paul Passy, Romain Le Gendre, Gilles Billen, Maia Akopian, and Goulven Gildas Laruelle. "Nutrient transport and transformation in macrotidal estuaries of the French Atlantic coast: a modeling approach using the Carbon-Generic Estuarine Model." Biogeosciences 19, no. 3 (February 15, 2022): 931–55. http://dx.doi.org/10.5194/bg-19-931-2022.
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Abstract. Estuaries are key reactive ecosystems along the land–ocean aquatic continuum, with significant ecological and economic value. However, they have been facing strong morphological management changes and increased nutrient and contaminant inputs, possibly leading to ecological problems such as coastal eutrophication. Therefore, it is necessary to quantify the import and export fluxes of the estuaries, their retention capacity, and estuarine eutrophication potential. The 1-D Carbon-Generic Estuary Model (C-GEM) was used to simulate the transient hydrodynamics, transport, and biogeochemistry for estuaries with different sizes and morphologies along the French Atlantic coast during the period 2014–2016 using readily available geometric, hydraulic, and biogeochemical data. These simulations allowed us to evaluate the budgets of the main nutrients (phosphorus – P; nitrogen – N; silica – Si) and total organic carbon (TOC), and their imbalance, providing insights into their eutrophication potential. Cumulated average annual fluxes to the Atlantic coast from the seven estuaries studied were 9.6 kt P yr−1, 259 kt N yr−1, 304 kt Si yr−1, and 145 kt C yr−1. Retention rates varied depending on the estuarine residence times, ranging from 0 %–27 % and 0 %–34 % to 2 %–39 % and 8 %–96 % for total phosphorus (TP), total nitrogen (TN), dissolved silica (DSi), and TOC, respectively. Large-scale estuaries had higher retention rates than medium and small estuaries, which we interpreted in terms of estuarine residence times. As shown by the indicator of eutrophication potential (ICEP), there might be a risk of coastal eutrophication, i.e., the development of non-siliceous algae that is potentially harmful to the systems studied due to the excess TN over DSi. This study also demonstrates the ability of our model to be applied with a similar setup to several estuarine systems characterized by different sizes, geometries, and riverine loads.
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Hirst, A. J., and R. Kilpatrick. "Spatial and temporal variation in the structure of estuarine macroinvertebrate assemblages: implications for assessing the health of estuaries." Marine and Freshwater Research 58, no. 9 (2007): 866. http://dx.doi.org/10.1071/mf06219.
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As human impacts in estuaries are often pervasive (estuary-wide) and/or pre-existing, the identification of suitable reference points, from which to assess the extent of impacts, is problematic. One solution is to compare potentially degraded estuaries with estuaries deemed to be largely unmodified by human activities. However, there is a perception that individual estuaries are too spatially and temporally dynamic to allow valid comparisons to be made using such an approach. We tested this idea for a commonly used indicator, benthic macroinvertebrates, using a factorial design incorporating both temporal and spatial scales between and within three adjacent meso-tidal river estuaries in northern Tasmania. Variation in macroinvertebrate assemblage structure was analysed using permutational multivariate analysis of variance. Most variance occurred within estuaries (68–82% variance) relative to spatial differences between estuaries (24–14%) corresponding with a strong upstream estuarine gradient and small-scale spatial patchiness. Seasonal variation accounted for 9–4% of total variance indicating that temporal differences were relatively insignificant when contrasted against spatial variability within and between estuaries. We suggest that with sufficient spatial replication at the within estuary-scale, entire estuaries may act as whole reference systems, allowing studies to examine potential impacts within estuaries with spatially diffuse, pre-existing human impacts.
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Kolpakov, Nickolay V. "Anthropogenic pollution of estuaries in south Primorye: a review." Izvestiya TINRO 187, no. 4 (December 30, 2016): 3–18. http://dx.doi.org/10.26428/1606-9919-2016-187-3-18.
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Cited data on anthropogenic pollution of the estuaries in south Primorye (northwestern coast of the Japan Sea) are briefly reviewed and analyzed. The estuaries are ranked by concentration of pollutants in the sewage disposed to the rivers and by integrated abiotic index calculated as the sum of toxicity in the bottom sediments and concentration of petrohydrocarbons in water and grounds. By these parameters, the oligohaline estuaries of big rivers as the Razdolnaya and Artemovka have the highest level of pollution, the mesohaline estuaries as the Tesnaya, Gladkaya, and Kievka have the intermediate rank of anthropogenic impact, and the polyhaline estuaries of small rivers as the Sukhodol, Shkotovka, Barabashevka, and Ryazanovka are low polluted. The estuarine ecosystems are generally well-adapted to high variability of environmental factors, and therefore are highly resistant to anthropogenic pollution. There is concluded that, despite of considerable pollution in some cases, dynamics of the estuaries dwellers abundance is determined mainly by natural factors, first of all by the volume of freshwater discharge, the estuarine ecosystems in Primorye function normally, and the state of their biological resources is sufficient. Thus, fishery, aquaculture, and recreations have at present good prospects in the estuaries and adjacent marine and river waters, in parallel with other economic activity, as hydraulic constructions, certainly under condition of all requirements of the nature protection legislation and with ecological monitoring. For these water bodies, technological and economic development can successively coexist with traditional nature management and wildlife preserving.
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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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Khojasteh, Danial, Shengyang Chen, Stefan Felder, Valentin Heimhuber, and William Glamore. "Estuarine tidal range dynamics under rising sea levels." PLOS ONE 16, no. 9 (September 20, 2021): e0257538. http://dx.doi.org/10.1371/journal.pone.0257538.
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How an estuary responds to sea level rise (SLR) is complex and depends on energy drivers (e.g., tides and river inflows), estuarine geometry (e.g., length and depth), intrinsic fluid properties (e.g., density), and bed/bank roughness. While changes to the tidal range under SLR can impact estuarine sediment transport, water quality, and vegetation communities, studies on the altered tidal range under SLR are often based on case studies with outcomes applicable to a specific site. As such, this study produced a large ensemble of estuarine hydrodynamic models (>1800) to provide a systematic understanding of how tidal range dynamics within different estuary types may change under various SLR and river inflow scenarios. The results indicated that SLR often amplifies the tidal range of different estuary types, except for short estuaries with a low tidal range at the mouth where SLR attenuates the tides. SLR alters the location of the points with minimum tidal range and overall tidal range patterns in an estuary. Variations in tidal range were more evident in converging estuaries, shallower systems, or in estuaries with strong river inflows. These findings provide an indication of how different estuary types may respond to estuaries and may assist estuarine managers and decision makers.
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Dobbie, Melissa J., and David Clifford. "Quantifying uncertainty in environmental indices: an application to an estuarine health index." Marine and Freshwater Research 66, no. 2 (2015): 95. http://dx.doi.org/10.1071/mf13065.
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Estuaries are an important link between terrestrial and marine ecosystems, so assessing their health and what influences it can help guide future ecosystem monitoring and management. But estuaries can be complex and dynamic systems, so summarising health by a single score or grade raises questions about interpretation, variability, sensitivity and confidence. Such questions may include how variable is the score for a particular waterway, how sensitive is the score to seemingly benign decisions taken to reach that score, and how different is the B grade of one waterway to the C scored by an adjacent waterway. Focusing on a specific estuarine health index, we quantified two different sources of variation in its construction and examined how they contributed to the variability of the final score. We found that quantifying the variability in two steps of the index construction enabled us to make more informed inferences about the index and its bearing on an overall report card score for an estuary. By highlighting uncertainty in an estuarine health index, we are improving its inferential value and enabling more defensible decision-making about current and future management and amelioration of an estuary’s health and function.
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Hodgkin, Ernest P., and Patrick Hesp. "Estuaries to salt lakes: Holocene transformation of the estuarine ecosystems of south-western Australia." Marine and Freshwater Research 49, no. 3 (1998): 183. http://dx.doi.org/10.1071/mf96109.
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When the estuaries of south-western Australia were first flooded by the Holocene marine transgression about 7000 years before present (BP), most were enclosed by limestone barrier dunes. Coastal sand drift built bars and flood-tide deltas in the narrow entrances, but until about 3500 years BP the estuaries remained tidal-dominated systems with a diverse marine–estuarine fauna. Now the bars/deltas so obstruct the small tides that estuary water is fresh in winter and marine to hypersaline in summer; the estuaries are river-flow-dominated systems and the ecosystems are characterised by a restricted euryhaline estuarine biota. Some estuaries are still permanently open, their bars/deltas never close, and some are seasonally open, their bars open with river flow in winter and close in summer. Other estuaries are normally closed, their bars remain closed for several years and break with episodic flood flow, or are permanently closed coastal salt lakes with bars that never or rarely break: they can become grossly hypersaline and may dry up altogether. An hypothesis to explain this Holocene transformation of the estuaries attributes it principally to sedimentary processes in an environment where river flow is highly seasonal, tides are microtidal, there was a fall in sea level, and there are differences in the volume and periodicity of flow and the degree of shelter to the entrances from the prevailing south-west winds and swell.
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Bissoli, Lorena B., and Angelo F. Bernardino. "Benthic macrofaunal structure and secondary production in tropical estuaries on the Eastern Marine Ecoregion of Brazil." PeerJ 6 (February 28, 2018): e4441. http://dx.doi.org/10.7717/peerj.4441.
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Tropical estuaries are highly productive and support diverse benthic assemblages within mangroves and tidal flats habitats. Determining differences and similarities of benthic assemblages within estuarine habitats and between regional ecosystems may provide scientific support for management of those ecosystems. Here we studied three tropical estuaries in the Eastern Marine Ecoregion of Brazil to assess the spatial variability of benthic assemblages from vegetated (mangroves) and unvegetated (tidal flats) habitats. A nested sampling design was used to determine spatial scales of variability in benthic macrofaunal density, biomass and secondary production. Habitat differences in benthic assemblage composition were evident, with mangrove forests being dominated by annelids (Oligochaeta and Capitellidae) whereas peracarid crustaceans were also abundant on tidal flats. Macrofaunal biomass, density and secondary production also differed between habitats and among estuaries. Those differences were related both to the composition of benthic assemblages and to random spatial variability, underscoring the importance of hierarchical sampling in estuarine ecological studies. Given variable levels of human impacts and predicted climate change effects on tropical estuarine assemblages in Eastern Brazil, our data support the use of benthic secondary production to address long-term changes and improved management of estuaries in Eastern Brazil.
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Watts, Robyn J., and Michael S. Johnson. "Estuaries, lagoons and enclosed embayments: habitats that enhance population subdivision of inshore fishes." Marine and Freshwater Research 55, no. 7 (2004): 641. http://dx.doi.org/10.1071/mf04051.
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Several studies have suggested that estuaries, lagoons and enclosed embayments may offer special opportunities for local subdivision in marine species. We used data from published papers and unpublished theses to examine the effect of such water bodies on allozyme differentiation of seven species of inshore fishes in Western Australia. We included species that differ in their dispersal, and hence their intrinsic potential for gene flow. Over large distances, subdivision was generally greater among estuarine populations than among conspecific marine populations collected over similar distances. Over small distances, paired marine and estuarine samples were generally more divergent than pairs of marine samples separated by similar distances. For species with a low capability for dispersal, estuaries appear to add to the high levels of genetic subdivision that commonly result from other factors. Under special circumstances estuaries may also provide opportunities for genetic divergence in species with a high capability of dispersal that are rarely subdivided at a large geographical scale. These observations indicate that estuaries can increase the genetic subdivision of populations of inshore fishes, and that species that use both marine and estuarine habitats are likely to have greater genetic subdivision than those that are restricted to marine habitats.
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Khojasteh, Danial, Tej Vibhani, Hassan Shafiei, William Glamore, and Stefan Felder. "Application of Idealised Modelling and Data Analysis for Assessing the Compounding Effects of Sea Level Rise and Altered Riverine Inflows on Estuarine Tidal Dynamics." Journal of Marine Science and Engineering 11, no. 4 (April 11, 2023): 815. http://dx.doi.org/10.3390/jmse11040815.
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Estuaries worldwide are experiencing increasing threats from climate change, particularly from the compounding effects of sea level rise (SLR) and varying magnitude of river inflows. Understanding the tidal response of estuaries to these effects can guide future management and help assess ecological concerns. However, there is limited existing understanding on how estuarine tidal dynamics may respond to the compounding effects of SLR and altered riverine inflows in different estuaries. To partially address this knowledge gap, this study used data analysis and scrutinised idealised hydrodynamic models of different estuary shapes and boundary conditions to (i) identify broad effects of SLR on estuarine tidal dynamics under various river inflow conditions, (ii) determine how longitudinal cross-sections are impacted by these effects, and (iii) highlight some implications for environmental risk management. Results indicated that short- to moderate-length, high convergent estuaries experience the greatest and short- to moderate-length prismatic and low convergent estuaries experience the least variations in their overall tidal dynamics (i.e., tidal range, current velocity, and asymmetry). These variations were most evident in estuaries with large riverine inflows and macrotidal conditions. Compounding effects of SLR and altered riverine inflows induced spatially heterogenous changes to tidal range, current velocity, and asymmetry, with transects nearest to the estuary mouth/head and at a three-quarter estuary length (measured from estuary mouth) identified as the most and the least vulnerable zones, respectively. These findings provide an initial broad assessment of some effects of climate change in estuaries and may help to prioritise future investigations.
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Khojasteh, Danial, Stefan Felder, Valentin Heimhuber, and William Glamore. "SEA LEVEL RISE IMPLICATIONS FOR ESTUARINE MODELLING AND MANAGEMENT." Coastal Engineering Proceedings, no. 37 (September 1, 2023): 113. http://dx.doi.org/10.9753/icce.v37.management.113.
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Estuaries provide a wide range of environmental, cultural, social, and economic services. These include primary production, water purification, recreational opportunities, navigational routes, and nurseries for aquatic species. However, a growing body of literature indicates that sea level rise (SLR) is increasingly threatening these services in estuaries due to their low-lying topography and proximity to the open ocean. As such, sustainable management of estuaries, adjacent low-lying areas, and associated ecosystems requires a thorough and evidence-based understanding of how different estuaries may respond to SLR over time and space (Khojasteh et al. (2021)). This, in turn, would help policymakers manage the far-reaching impacts and prioritise funds-based adaptation and mitigation strategies. Assessing SLR impacts in estuaries can either be undertaken on an individual site basis or via broader approaches that may be relevant to many estuaries. This study utilises the latter approach and, to this aim, a large ensemble of idealised prismatic and converging estuarine hydrodynamic simulations were conducted.
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Kennish, Michael J. "Environmental threats and environmental future of estuaries." Environmental Conservation 29, no. 1 (March 2002): 78–107. http://dx.doi.org/10.1017/s0376892902000061.
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Estuaries exhibit a wide array of human impacts that can compromise their ecological integrity, because of rapid population growth and uncontrolled development in many coastal regions worldwide. Long-term environmental problems plaguing estuaries require remedial actions to improve the viability and health of these valuable coastal systems. Detailed examination of the effects of pollution inputs, the loss and alteration of estuarine habitat, and the role of other anthropogenic stress indicates that water quality in estuaries, particularly urbanized systems, is often compromised by the overloading of nutrients and organic matter, the influx of pathogens, and the accumulation of chemical contaminants. In addition, the destruction of fringing wetlands and the loss and alteration of estuarine habitats usually degrade biotic communities. Estuaries are characterized by high population densities of microbes, plankton, benthic flora and fauna, and nekton; however, these organisms tend to be highly vulnerable to human activities in coastal watersheds and adjoining embayments. Trends suggest that by 2025 estuaries will be most significantly impacted by habitat loss and alteration associated with a burgeoning coastal population, which is expected to approach six billion people. Habitat destruction has far reaching ecological consequences, modifying the structure, function, and controls of estuarine ecosystems and contributing to the decline of biodiversity. Other anticipated high priority problems are excessive nutrient and sewage inputs to estuaries, principally from land-based sources. These inputs will lead to the greater incidence of eutrophication as well as hypoxia and anoxia. During the next 25 years, overfishing is expected to become a more pervasive and significant anthropogenic factor, also capable of mediating global-scale change to estuaries. Chemical contaminants, notably synthetic organic compounds, will remain a serious problem, especially in heavily industrialized areas. Freshwater diversions appear to be an emerging global problem as the expanding coastal population places greater demands on limited freshwater supplies for agricultural, domestic, and industrial needs. Altered freshwater flows could significantly affect nutrient loads, biotic community structure, and the trophodynamics of estuarine systems. Ecological impacts that will be less threatening, but still damaging, are those caused by introduced species, sea level rise, coastal subsidence, and debris/litter. Although all of these disturbances can alter habitats and contribute to shifts in the composition of estuarine biotic communities, the overall effect will be partial changes to these ecosystem components. Several strategies may mitigate future impacts.
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Bernardino, Angelo Fraga, Paulo Roberto Pagliosa, Ronaldo Adriano Christofoletti, Francisco Barros, Sergio A. Netto, Pablo Muniz, and Paulo da Cunha Lana. "Benthic estuarine communities in Brazil: moving forward to long term studies to assess climate change impacts." Brazilian Journal of Oceanography 64, spe2 (2016): 81–96. http://dx.doi.org/10.1590/s1679-875920160849064sp2.
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Abstract Estuaries are unique coastal ecosystems that sustain and provide essential ecological services for mankind. Estuarine ecosystems include a variety of habitats with their own sediment-fauna dynamics, all of them globally undergoing alteration or threatened by human activities. Mangrove forests, saltmarshes, tidal flats and other confined estuarine systems are under increasing stress due to human activities leading to habitat and species loss. Combined changes in estuarine hydromorphology and in climate pose severe threats to estuarine ecosystems on a global scale. The ReBentos network is the first integrated attempt in Brazil to monitor estuarine changes in the long term to detect and assess the effects of global warming. This paper is an initial effort of ReBentos to review current knowledge on benthic estuarine ecology in Brazil. We herein present and synthesize all published work on Brazilian estuaries that has focused on the description of benthic communities and related ecological processes. We then use current data on Brazilian estuaries and present recommendations for future studies to address climate change effects, suggesting trends for possible future research and stressing the need for long-term datasets and international partnerships.
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Denis, Jérémy, Mario Lepage, Marie-Christine Gruselle, and Rachid Amara. "The Influence of Natural and Anthropogenic Environmental Pressures on European Eel Abundances in French Estuaries." Fishes 9, no. 2 (January 23, 2024): 44. http://dx.doi.org/10.3390/fishes9020044.
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The aim of this study was to investigate the influence of environmental characteristics and anthropogenic pressures on the abundance of estuarine European eels (Anguilla anguilla L.) during their continental growth phase. European eels were collected with fyke nets from spring to autumn in twenty-nine estuaries along the French English Channel and the Atlantic coast. Eel abundance (catch per unit effort, CPUE) was assessed for all eels and by size class for small (total length < 300 mm), intermediate (≥300 to <450 mm), and large (≥450 mm) eels. The environmental characteristics of the French estuaries were described by twelve descriptor variables, mainly related to hydro-morphological and sedimentary factors. Based on principal component analysis and hierarchical clustering analysis, estuary size was identified as the main explanatory variable and used to compare eel abundance. Eel abundance differed significantly according to estuary size, with higher abundances observed in small estuaries (7.22 to 13.00 ind. fyke nets 24 h−1) compared to large estuaries (0.13 to 0.71 ind. fyke nets 24 h−1). Spatial variation in eel abundance was correlated with differences in estuary size for all eel size classes. The influence of anthropogenic pressures on eel abundance was assessed by nine anthropogenic estuarine pressure indicators. The results indicate that high values of the anthropogenic pressure indicators were correlated with low eel abundance. This study highlights that large French estuaries subject to stronger anthropogenic pressures were less favourable habitats than small estuaries with less anthropogenic pressure.
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Meeuwig, Jessica J., Pirkko Kauppila, and Heikki Pitkänen. "Predicting coastal eutrophication in the Baltic: a limnological approach." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 4 (April 1, 2000): 844–55. http://dx.doi.org/10.1139/f00-013.
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Coastal eutrophication is a key environmental concern in Finland. A highly indented, well-settled coastline with a myriad of small estuaries means that eutrophication occurs at numerous localities. There is a clear need for general models that predict eutrophication across estuaries. Lake eutrophication has been successfully predicted using a combination of chlorophyll a (Chl) - total phosphorus (TP) regression models and TP mass-balance models. We applied this limnological approach to 19 Finnish estuaries. The Chl-TP regression was highly significant, accounting for 67% of the variation in Chl. When combined with a TP mass-balance equation, log observed and predicted Chl differed by 28% on average. Accuracy was improved by dividing the estuaries into those dominated by non-point-source (NPS) loading (n = 11) and those dominated by point-source (PS) loading (n = 7). A land-use regression model based on percentage of the catchment forested and estuarine mean depth then best predicted Chl in the NPS-dominated estuaries. The mass-balance approach remained the most accurate model for the PS estuaries. The land-use model and mass-balance approach are complementary tools in that their use maximizes accuracy for both NPS- and PS-dominated estuaries. This high level of accuracy demonstrates the relevance of limnological approaches to Finnish estuaries.
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Groeneveld, Johan C., Jorge Santos, Fiona MacKay, and Cosmas N. Munga. "A regional assessment of seasonal-to-decadal changes in estuarine socio-ecological systems in the Western Indian Ocean." Western Indian Ocean Journal of Marine Science, no. 1/2021 (December 23, 2021): 131–61. http://dx.doi.org/10.4314/wiojms.si2021.1.9.
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Estuarine socio-ecological systems (SES) in the Western Indian Ocean (WIO) region face mounting pressures from overexploitation, habitat degradation, impacts of climate change and governance inadequacies. A regional assessment of seasonal-to-decadal change in SES of three estuaries (Bons Sinais in Mozambique, Ruvu in Tanzania and Tana in Kenya) was undertaken along 2000 km of tropical coastline (3°-18°S), using a systems-oriented approach and information collected during the Estuarize-WIO project (2016-2019). All three estuaries were open and tidal, but differed along gradients of geomorphology, annual precipitation, exposure to tropical storms, drought, sea level rise, and rural to urban development. Despite physical differences, similar marine species, mangrove assemblages, seasonality in fish-based farming systems and cultivated crops, and fishing methods were apparent across the region. Key differences were related to the scale of anthropogenic disturbance, discerned from land use / land cover (LULC) change analysis, which showed decadal increases in developed-, cultivated- and grasslands, at the expense of wetlands and forests, and seasonal transformation of wetlands to agriculture and grasslands. The three estuaries represented a gradient along urban-production-conservation dimensions, brought about by rural to urban transformation, and by freshwater and sediment diversion for economic development in upstream catchment areas. Household surveys indicated strongly seasonal livelihood strategies, with highest diversity in peri-urban settings, and reliance on different combinations of ecosystem goods and services in coastal and upstream rural settings. Estuarine fisheriesranged from unselective, low trophic-level fisheries using fine-mesh nets at the urbanized and most-disturbed Bons Sinais Estuary, to a more complex organized fishery at the least-disturbed Tana. At Ruvu, fisheries and agriculture production exit the system to distant markets. The systems-oriented approach demonstrated that human-induced processes affected WIO estuaries and dependent livelihoods more deeply than inherent physical differences. A key conclusion is that research, management and governance will benefit from regional cooperation, given the similarities of the systems and the different levels of disturbance.
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Logan, Brendan, and Kathryn H. Taffs. "Seasonal water-quality sampling in estuaries, what can it tell us? A case example of eastern Australian subtropical estuaries." Marine and Freshwater Research 65, no. 2 (2014): 153. http://dx.doi.org/10.1071/mf12338.
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Point-sampling of water is often referred to as an inaccurate and crude method for use in estuaries; however, budgetary, spatial and time constraints often leave it as the only feasible option. The present paper investigates the relationship between spring water quality and diatom sampling of 52 eastern Australian subtropical estuaries and the OzCoasts determined classification of estuarine condition. In general, estuarine health decreases along the total phosphorus (TP), total nitrogen (TN) and the centric to pennate diatom ratio gradients. However, although there is a general trend, results are varied within each class, with some estuaries classed as extensively modified, recording low nutrient conditions. Principal components analysis (PCA) indicated that 55% of the variance among sites is explained by the first and second axes, with TN, TP, TN : TP, latitude and pH having high correlation with PCA Axis 1, and temperature, conductivity and the centric to pennate diatom ratio being correlated with Axis 2. Two diatom species that may have bioindicator value for estuary conditions were identified. We concluded that even though natural variability and accurate characterisation of estuaries is not possible with point-sampling, it can still identify important information on the status of estuarine condition, particularly in relation to total nutrient concentrations where budget and/or time constraints limit environmental monitoring.
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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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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.
Full textAbstract:
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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MAGRIS, R. A., and L. F. LOUREIRO FERNANDES. "Diversity and distribution of assemblages of estuarine decapod larvae (Crustacea: Decapoda: Anomura, Brachyura) in tropical southeastern Brazil." Zootaxa 2758, no. 1 (February 7, 2011): 26. http://dx.doi.org/10.11646/zootaxa.2758.1.2.
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Decapod larvae assemblages were studied in the tropical estuaries off southeastern Brazil (Piraquê-açú and Piraquê-mirim rivers estuaries). A total of 32 taxa of decapod larvae were recorded. Brachyuran larvae dominated in Piraquê-açú estuary, with 62% of the relative abundance, and 49% in Piraquê-mirim estuary. Mean larvae concentrations ranged from 17.2 m -3 at Piraquê-mirim (August 2003) to 221.1 m -3 at Piraquê-açú (April 2003). The assemblage of larvae in both estuaries was diverse, especially at Piraquê-mirim, which showed higher ecological stability. The high spatial heterogeneity of the Piraquê-açú and Piraquê-mirim estuarine system resulted in the division of the assemblage into two well-defined groups (truly estuarine and euryhaline). Salinity spatial gradient was a key factor in the structure and distribution of larvae.
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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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Müller, Denise, Hermann W. Bange, Thorsten Warneke, Tim Rixen, Moritz Müller, Aazani Mujahid, and Justus Notholt. "Nitrous oxide and methane in two tropical estuaries in a peat-dominated region of northwestern Borneo." Biogeosciences 13, no. 8 (April 26, 2016): 2415–28. http://dx.doi.org/10.5194/bg-13-2415-2016.
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Abstract. Estuaries are sources of nitrous oxide (N2O) and methane (CH4) to the atmosphere. However, our present knowledge of N2O and CH4 emissions from estuaries in the tropics is very limited because data are scarce. In this study, we present first measurements of dissolved N2O and CH4 from two estuaries in a peat-dominated region of northwestern Borneo. Two campaigns (during the dry season in June 2013 and during the wet season in March 2014) were conducted in the estuaries of the Lupar and Saribas rivers. Median N2O concentrations ranged between 7.2 and 12.3 nmol L−1 and were higher in the marine end-member (13.0 ± 7.0 nmol L−1). CH4 concentrations were low in the coastal ocean (3.6 ± 0.2 nmol L−1) and higher in the estuaries (medians between 10.6 and 64.0 nmol L−1). The respiration of abundant organic matter and presumably anthropogenic input caused slight eutrophication, which did not lead to hypoxia or enhanced N2O concentrations, however. Generally, N2O concentrations were not related to dissolved inorganic nitrogen concentrations. Thus, the use of an emission factor for the calculation of N2O emissions from the inorganic nitrogen load leads to an overestimation of the flux from the Lupar and Saribas estuaries. N2O was negatively correlated with salinity during the dry season, which suggests a riverine source. In contrast, N2O concentrations during the wet season were not correlated with salinity but locally enhanced within the estuaries, implying that there were additional estuarine sources during the wet (i.e., monsoon) season. Estuarine CH4 distributions were not driven by freshwater input but rather by tidal variations. Both N2O and CH4 concentrations were more variable during the wet season. We infer that the wet season dominates the variability of the N2O and CH4 concentrations and subsequent emissions from tropical estuaries. Thus, we speculate that any changes in the Southeast Asian monsoon system will lead to changes in the N2O and CH4 emissions from these systems. We also suggest that the ongoing cultivation of peat soil in Borneo is likely to increase N2O emissions from these estuaries, while the effect on CH4 remains uncertain.
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Leal Filho, Walter, Gustavo J. Nagy, Filipe Martinho, Mustafa Saroar, Mónica Gómez Erache, Ana Lígia Primo, Miguel A. Pardal, and Chunlan Li. "Influences of Climate Change and Variability on Estuarine Ecosystems: An Impact Study in Selected European, South American and Asian Countries." International Journal of Environmental Research and Public Health 19, no. 1 (January 5, 2022): 585. http://dx.doi.org/10.3390/ijerph19010585.
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It is well-known that climate change significantly impacts ecosystems (at the macro-level) and individual species (at the micro-level). Among the former, estuaries are the most vulnerable and affected ecosystems. However, despite the strong relations between climate change and estuaries, there is a gap in the literature regarding international studies across different regions investigating the impacts of climate change and variability on estuaries in different geographical zones. This paper addresses this need and reviews the impacts of climate change, variability and extreme weather on estuaries. It emphasises the following: (i) a set of climate parameters governing estuarine hydrology and processes; and (ii) a sample of countries in Asia (Bangladesh), Europe (Portugal) and South America (Uruguay). We reviewed the influences of the climatic drivers of the estuarine hydrology, ecological processes and specific species in estuarine communities across the selected geographical regions, along with an analysis of their long-term implications. The key results from the three estuaries are as following: (i) Hilsa fish, of which the catches contribute to 10% of the total earnings of the fishery sector (1% of GDP), are affected by climate-forced hydrological and productivity changes in the Meghna; (ii) extreme droughts and short-term severe precipitation have driven the long-term abundance and spatial distribution of both fish larvae and juveniles/adults in the Mondego; and (iii) the river inflow and fluctuations increases since the early 1970s have contributed to variations in the salinity, the stratification, the oxygen, nutrient and trophic levels and the spatial pattern for the life stages of planktonic species, fish biomass and captures in the Rio de la Plata. The results suggested that immediate action is needed to reduce the vulnerability of estuaries to climate stressors, mainly the changing river flows, storms and sea-level rise. As a contribution to addressing current problems, we described a set of adaptation strategies to foster climate resilience and adaptive capacity (e.g., early-warning systems, dam management to prevent overflows and adaptive fisheries management). The implications of this paper are two-fold. Firstly, it showcases a variety of problems that estuaries face from changing climate conditions. Secondly, the paper outlines the need for suitable adaptive management strategies to safeguard the integrity of such vital ecosystems.
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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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Henderson, Christopher J., Ben L. Gilby, Thomas A. Schlacher, Rod M. Connolly, Marcus Sheaves, Nicole Flint, Hayden P. Borland, and Andrew D. Olds. "Contrasting effects of mangroves and armoured shorelines on fish assemblages in tropical estuarine seascapes." ICES Journal of Marine Science 76, no. 4 (February 4, 2019): 1052–61. http://dx.doi.org/10.1093/icesjms/fsz007.
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Abstract Coastal seascapes are composed of a diversity of habitats that are linked in space and time by the movement of organisms. The context and configuration of coastal ecosystems shapes many important properties of animal assemblages, but potential seascape effects of natural and artificial habitats on nearby habitats are typically considered in isolation. We test whether, and how, the seascape context of natural and urban habitats modified fish assemblages across estuaries. Fish were sampled with underwater videos in five habitat types (mangroves, rock bars, log snags, unvegetated sediments, armoured shorelines) in 17 estuaries in eastern Australia. Different habitats supported distinct fish assemblages, but the spatial context of mangroves and armoured shorelines had pervasive ecological effects that extended across entire estuaries. In most estuarine habitats, fish diversity and abundance was greatest when they were in close proximity of mangroves, and decreased due to the proximity of armoured shorelines. Many cities are centred on estuaries, and urban expansion is often associated with the fragmentation of mangrove forests. Our findings emphasize that these transformations of urban estuarine landscapes are likely to propagate to broader ecological impacts detectable in multiple habitats beyond mangrove forests.
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Wang, Zhongyuan, and Hongkang Zhang. "A Proposed Methodology for the Dynamic Standard Evaluation of Water Quality in Estuaries: A Case Study of the Pearl River Estuary." Journal of Marine Science and Engineering 12, no. 7 (June 21, 2024): 1039. http://dx.doi.org/10.3390/jmse12071039.
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Currently, China’s river water quality evaluation adopts the “Environmental Quality Standards for Surface Water”, while the seawater quality evaluation uses the “Seawater Quality Standard”. However, estuarine areas, where rivers meet the sea, do not have evaluation standards, and most often, the “Seawater Quality Standard” is applied. At present, the water quality in the estuary area sometimes exceeds the corresponding seawater quality standards, even though the quality of the surface water does not exceed surface water environmental quality standards and the quality of the seawater before mixing also meets the seawater quality standards. This paper proposes a dynamic evaluation standard based on the salinity of estuarine water and uses this standard to evaluate the water quality in estuaries, thus solving the abovementioned issue. The implementation of this method is simple and effective. Taking the Pearl River Estuary as an example, this paper introduces the dynamic standard evaluation method for water quality in the Pearl River Estuary. Compared to the existing seawater quality standards implemented in estuaries, this dynamic evaluation standard can assess the water quality in estuaries more accurately and provide a reference for water quality evaluation methods in estuaries.
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Acha, Eduardo M., Hermes Mianzan, Carlos A. Lasta, and Raúl A. Guerrero. "Estuarine spawning of the whitemouth croaker Micropogonias furnieri (Pisces : Sciaenidae), in the Río de la Plata, Argentina." Marine and Freshwater Research 50, no. 1 (1999): 57. http://dx.doi.org/10.1071/mf98045.
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Most fishes that take advantage of the high productivity of estuaries exhibit offshore spawning, produce great numbers of small pelagic eggs and recruit to estuaries as larvae or juveniles. The reproductive pattern of Micropogonias furnieri (a planktonic egg spawner) in the Río de la Plata estuary (36°S,56°W) differs from this. Biological sampling and oceanographic data showed that the spawning area covers a narrow band across the river between Montevideo (34°50´8S,56°10´W) and Punta Piedras (35°25´S,57°10´W) at depths ranging from 6 to 8 m. This area is characterized by strong haloclines, reaching 21.5 units m-1. M. furnieri eggs were present only below the halocline, in salinities of 9.7–27.3, and at 18.5–20.2°C. Spawning occurred in the innermost part of the estuary, near the upstream edge of the salinity wedge and coinciding with the turbidity maximum (up to 150 mg L-1). The regular spawning of pelagic eggs has been reported in estuaries of southern Africa and Australia characterized by intermittent landlocking. The present results show that a large estuary may also provide the opportunity for successful spawning of pelagic eggs. Resumen. La mayoría de los peces que aprovechan la alta productividad de los estuarios efectúan sus desoves en el océano, producen gran cantidad de pequeños huevos pelágicos, y se reclutan a los estuarios como larvas o juveniles. El patrón reproductivo de Micropogonias furnieri (un desovante de huevos planctónicos) en el Río de la Plata (36°S,56°W), resulta diferente. Muestreos biológicos y datos oceanográficos demuestran que su área de desove cubre una estrecha franja a través del río, entre Montevideo (34°50´S,56°10´W) y Punta Piedras (35°25´S,57°10´W), en profundidades de 6 a 8 m. Esta área se caracteriza por fuertes haloclinas, de hasta 21.5 unidades m-1. Los huevos de M. furnieri se encuentran sólo debajo de la haloclina, en salinidades de 9.7 a 27.3, y temperaturas de 18.5° a 20.2°C. El desove tiene lugar en la parte más interna del estuario, cerca del límite río arriba de la cuña salina, y en coincidencia con el máximo de turbidez (hasta 150 mg L-1). En estuarios del sur de Africa y Australia, caracterizados por el cierre intermitente de su boca, ha sido reportado el desove regular de huevos planctónicos. Nuestros resultados demuestran que un gran estuario también puede proveer la oportunidad para el desove exitoso de huevos planctónicos.
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Siddiqee, Mahbubul, Rebekah Henry, Rebecca Coulthard, Christelle Schang, Richard Williamson, Rhys Coleman, Graham Rooney, Ana Deletic, and David McCarthy. "Salmonella enterica Serovar Typhimurium and Escherichia coli Survival in Estuarine Bank Sediments." International Journal of Environmental Research and Public Health 15, no. 11 (November 21, 2018): 2597. http://dx.doi.org/10.3390/ijerph15112597.
Full textAbstract:
Estuarine bank sediments have the potential to support the survival and growth of fecal indicator organisms, including Escherichia coli. However, survival of fecal pathogens in estuarine sediments is not well researched and therefore remains a significant knowledge gap regarding public health risks in estuaries. In this study, simultaneous survival of Escherichia coli and a fecal pathogen, Salmonella enterica serovar Typhimurium, was studied for 21 days in estuarine bank sediment microcosms. Observed growth patterns for both organisms were comparable under four simulated scenarios; for continuous-desiccation, extended-desiccation, periodic-inundation, and continuous-inundation systems, logarithmic decay coefficients were 1.54/day, 1.51/day, 0.14/day, and 0.20/day, respectively, for E. coli, and 1.72/day, 1.64/day, 0.21/day, and 0.24/day for S. Typhimurium. Re-wetting of continuous-desiccated systems resulted in potential re-growth, suggesting survival under moisture-limited conditions. Key findings from this study include: (i) Bank sediments can potentially support human pathogens (S. Typhimurium), (ii) inundation levels influence the survival of fecal bacteria in estuarine bank sediments, and (iii) comparable survival rates of S. Typhimurium and E. coli implies the latter could be a reliable fecal indicator in urban estuaries. The results from this study will help select suitable monitoring and management strategies for safer recreational activities in urban estuaries.
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Henderson, Christopher J., Ben L. Gilby, Edward Stone, Hayden P. Borland, and Andrew D. Olds. "Seascape heterogeneity modifies estuarine fish assemblages in mangrove forests." ICES Journal of Marine Science 78, no. 3 (February 12, 2021): 1108–16. http://dx.doi.org/10.1093/icesjms/fsab022.
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Abstract Mangroves are a dominant structural habitat within tropical and subtropical estuaries that provide a number of ecosystem services, including habitat for a range of crustaceans and fish. However, mangroves are one of the most threatened estuarine habitats globally, having been severely reduced in extent, and replaced by urban structures. Here, we test for the effects of both natural (e.g. seagrass, rock and mangroves habitat extent, and connectivity) and human (e.g. extent of urban area) landscape variables on the number and type of fish inhabiting mangroves forests. We used remote underwater video stations to quantify fish assemblages within mangroves at 150 sites in 30 estuaries across Queensland, Australia. Fish community structure was best explained by the extent of mangroves and seagrasses within an estuary, the distance to the estuary mouth, and the size of the estuary and catchment. Moderate catchment size and proximity to the estuary mouth increased species richness and abundance of harvestable fish at individual mangrove sites. In order to maintain mangrove fish assemblages and the functions they provide, management initiatives should focus on maintaining natural estuarine seascapes that are located closer to the mouth of estuaries, in particular, focusing on estuaries that have lower levels of catchment urbanization.
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Asp, Nils Edvin, Carlos Augusto França Schettini, Eduardo Siegle, Marcio Sousa da Silva, and Roney Nonato Reis de Brito. "The dynamics of a frictionally-dominated Amazonian estuary." Brazilian Journal of Oceanography 60, no. 3 (September 2012): 391–403. http://dx.doi.org/10.1590/s1679-87592012000300011.
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The hydrodynamics, morphology and sedimentology of the Taperaçu estuary were investigated. This is one of several estuaries located within the largest mangrove fringe in the world, bordering the Amazon region, subject to a macrotidal regime and regionally atypical negligible fresh water supply. The results reveal widespread sand banks that occupy the central portion of the estuarine cross-section. Well-sorted very fine sandy sediments of marine origin prevail. Shorter flood phases, with substantially higher current velocities, were observed in the upper sector of Taperaçu, as expected for a shallow, friction-dominated estuary. However, ebb domination can be expected for estuaries with large associated mangrove areas and substantial estuarine infilling, both of which situations occur on the Taperaçu. The tidal asymmetry favoring flood currents could be the result of the absence of an effective fluvial discharge. Furthermore, it was observed that the Taperaçu is connected by tidal creeks to the neighboring Caeté estuary, allowing a stronger flux during the flood and intensifying the higher flood currents. As a whole, the results have shown a complex interaction of morphological aspects (friction, fluvial drainage, connections with neighbor estuaries, infilling and large storage area) in determining hydrodynamic patterns, thus improving the understanding of Amazon estuaries.
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Zhou, Tao, Bowen Cao, Junliang Qiu, Shirong Cai, Haidong Ou, Wei Fan, Xiankun Yang, Xuetong Xie, Yu Bo, and Gaige Zhang. "Mapping Suspended Sediment Changes in the Western Pacific Coasts." Remote Sensing 15, no. 21 (October 31, 2023): 5192. http://dx.doi.org/10.3390/rs15215192.
Full textAbstract:
The Western Pacific Coasts (WPC) are the outlets of many large Asian rivers. In recent years, the interplay of climate changes and human activities has persistently altered the suspended sediment concentrations (SSC) in the WPC, triggering substantial shifts in coastal ecosystems. However, the scarcity of coastal observation stations hampered comprehensive investigations at large scales. This study employed three representative SSC retrieval models and utilized Landsat images acquired from 1990 to 2020 to estimate the SSC in the WPC with a focused endeavor to dissect the intricate spatial and temporal variability of SSC in the region. The findings revealed the following insights: (1) The outcomes derived from the three distinct SSC models consistently manifested a discernible decreasing pattern in SSC changes over the past three decades across all six major estuaries (Liao River Estuary, Yellow River Estuary, Yangtze River Estuary, Hangzhou Bay, Pearl River Estuary, and Mekong River Estuary). (2) The seasonal attributes of the six major estuaries differed, primarily due to distinct dominant influencing factors like precipitation, upstream sediment load, wind, and tides. (3) Collectively, SSC tends to be relatively higher in the Yangtze River Estuary, Hangzhou Bay, and Yellow River Estuary, while the Pearl River and Mekong River Estuaries exhibit relatively lower levels. Notably, the SSC exhibited distinct spatial traits along the coastlines of different estuaries. (4) SSC in the non-estuarine regions along the WPC, a similar significant declining trend in SSC is observed as in the estuaries, albeit the rate of decline generally appeared to be less pronounced. Furthermore, regions with faster rates of SSC reduction are typically concentrated near major estuaries in the northern part of the Coasts. The decline in estuarine SSC plays an important role in the overall decrease in SSC across the WPC. These study outcomes held substantial significance for advancing the stability and sustainable evolution of the WPC.
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Siemes, Rutger W. A., Trang Minh Duong, Pim W. J. M. Willemsen, Bas W. Borsje, and Suzanne J. M. H. Hulscher. "Morphological Response of a Highly Engineered Estuary to Altering Channel Depth and Restoring Wetlands." Journal of Marine Science and Engineering 11, no. 11 (November 11, 2023): 2150. http://dx.doi.org/10.3390/jmse11112150.
Full textAbstract:
Estuaries are continuously adapting to anthropogenic pressure. Because of sea-level rise and reduced fluvial sediment supply, they are at risk of sediment starvation. Contrarily, some estuaries require frequent dredging after artificially deepening the channel to maintain port operations. To optimize current estuarine functions and make estuaries more resilient to future threats, improved understanding of estuarine development after system changes is essential. This paper investigates the estuarine response related to two large-scale human interventions: (1) altering channel depth, following global trends of channel deepening for port navigability; and (2) creating or restoring wetlands, a nature-based solution increasingly explored for its ecosystem services. A schematized 2D-morphological model is set up using Delft3D-FM reflecting a highly engineered estuary in a micro-tidal and wave-dominant environment. Results demonstrate how channel deepening (from 13 m to 17 m, without wetland presence) increased sedimentation in the channel by +31%. Sedimentation rates in the wetland were mostly unaffected by channel depth. After restoring the wetland area (wetland width from 0 km to 1 km, constant channel depth of 15 m), sedimentation within the channel was reduced by −72%. The wetland area not only served as sediment sink, but also increased the tidal flow, diminishing sedimentation throughout the estuarine channel. Further analysis showed that restoring wetland areas along a specific segment mostly affected channel sedimentation locally (i.e., at the channel segment along the restored wetland). As such, to alleviate dredging operations at critical locations in the navigation channel, strategic restoration of wetlands can be considered which can provide a sustainable alternative to dredging within highly engineered estuaries.
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Whitfield, AK. "Littoral habitats as major nursery areas for fish species in estuaries: a reinforcement of the reduced predation paradigm." Marine Ecology Progress Series 649 (September 10, 2020): 219–34. http://dx.doi.org/10.3354/meps13459.
Full textAbstract:
For many decades, the role of estuaries as important nursery areas for fishes was accepted as fact by scientists and environmental managers. At the turn of the 21st century, a question mark was raised in relation to the reduced predation component of the nursery function, with some scientists contending that both large and small piscivorous fish species had access to the estuarine habitats that juvenile fishes in estuaries occupied. If true on a global scale, the nursery designation for these habitats would be compromised and the long-held paradigm that estuaries are important nursery areas for fishes would need to be revised. In this review, I examine the nature of fish nursery areas in estuarine littoral habitats from a mainly predation perspective and, based on a variety of ichthyofaunal and avifaunal studies, come to the conclusion that apart from a few selected estuarine systems, there is limited predation on juvenile fishes in these particular areas. This, coupled with the abundant suitable food resources for juvenile fish from different trophic categories, shelter from high-energy marine wave action and biological connectivity between a variety of submerged and emergent macrophyte communities, renders shallow estuarine littoral areas ideal nursery areas for the juveniles of mostly euryhaline marine fish species, the dominant component of estuarine ichthyofaunas globally. In addition, there are strong indications from the fossil record that these littoral estuarine nursery areas have been functioning since the Devonian, more than 350 million years ago.
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Booi, Sipesihle, Syden Mishi, and Oddgeir Andersen. "Ecosystem Services: A Systematic Review of Provisioning and Cultural Ecosystem Services in Estuaries." Sustainability 14, no. 12 (June 14, 2022): 7252. http://dx.doi.org/10.3390/su14127252.
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It is widely argued that humans deteriorate and vandalize ecosystems, yet little is known about the advantages they receive from the same. The study employs the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach to identify studies on the value of ecosystems, with a focus on estuaries between the years 2000 to 2021. The review included a total of 61 studies, which highlighted: (a) the importance of estuarine ecosystem services; (b) the stress placed on estuaries as a result of human activity; and (c) the importance of ecosystem services to human well-being. These studies aid in our understanding of the provisioning and cultural services that ecosystems provide to humans, as well as how the ecosystem services assist individuals in diversifying their livelihoods. Our systematic review revealed that: (a) estuaries provide benefits to humans and are used for survival, (b) cultural ecosystem services are important and valuable; however, (c) as a result of human activities and climate change, ecosystem services face numerous threats such as pollution, overexploitation of resources, and poor water quality, among others. Future research should focus on how estuary users perceive the ecosystem services that estuaries provide, and there should be more publications and studies on the benefits that estuaries provide. The systematic review highlighted that most studies are outdated, there are few to no new studies on ecosystem services and estuaries, and those that are available do not directly address the importance of estuaries.
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Silva, Janaina Barbosa da, Josiclêda Domiciano Galvíncio, Antonio Carlos De Barros Corrêa, Danielle Gomes da Silva, and Célia Cristina Clemente Machado. "Classificação Geomorfológica dos Estuários do Estado de Pernambuco (Brasil) com Base em Imagens do LANDSAT 5/TM (Geomorphologic Classification of Estuaries of the State of Pernambuco (Brazil) Based on Landsat 5 TM Images)." Revista Brasileira de Geografia Física 4, no. 1 (July 17, 2011): 118. http://dx.doi.org/10.26848/rbgf.v4i1.232689.
Full textAbstract:
O presente estudo visou classificar os quinze estuários do Estado de Pernambuco, adotando como base as características geomorfológicas. A base de dados utilizada para a classificação foram imagens de satélites do Landsat 5-TM. Foram realizadas análises visuais das imagens de satélite e posteriormente efetuados trabalhos de campo com o intuito de validar as interpretações realizadas. Na zona costeira pernambucana os estuários classificam-se como: Planície Costeira (vale inundado), Formado por Barras e por Outros Processos. As interações espaço-temporal dos processos ambientais durante o Quaternário foram de fundamental importância para a atual configuração das áreas estuarinas classificadas, tendo em vista que tectonismo, erosão e sedimentação recorrente das regressões e transgressões marinhas foram processos recursivos durante a formação dos estuários e que deixaram registros na paisagem. Foram definidos como planície costeira os estuários do Goiana/Megaó, Jaguaribe, Paratibe, Maracaípe, Sirinhaém e Formoso. Do tipo construído pro barra tem-se o Timbó, Beberibe, Jaboatão/Pirapama, Mamucabas/Ilhetas e Una. Estuários tipo ria são os de Itapessoca e Canal de Santa Cruz, enquanto os de laguna costeira são o Ipojuca e o Capibaribe. Palavras-chave: Estuários, Zona Costeira Pernambucana, Quaternário Geomorphologic Classification of Estuaries of the State of Pernambuco (Brazil) Based on Landsat 5 TM Images ABSTRACT This study aimed to classify the fifteen estuaries of the State of Pernambuco-Brazil, using as base the geomorphological characteristics. The database used for the classification were satellite images of Landsat-5 TM. Were performed visual analysis of satellite images and were later made field work to validate the interpretations made. In the coastal zone of Pernambuco are found three classifications of estuaries: coastal plain (the flood plain), formed by bars and other processes. The space-time interactions of environmental processes during the Quaternary were of fundamental importance to the current configuration of estuarine areas classified in order to tectonics, erosion and sedimentation of the applicant marine transgressions and regressions were recursive processes during the formation of estuaries and left records in the landscape. Were defined as the coastal plain estuaries of Goiana/Megaó, Jaguaribe, Paratibe, Olinda, Sirinhaém and Formoso. Type built by bar has the Timbó, Beberibe, Jaboatão/Pirapama, Mamucaba/Ilhetas and Una. Estuaries are the kind of laughed Itapessoca and Channel and Santa Cruz, while the coastal lagoon and are Ipojuca and Capibaribe. Key-words: Estuary, coastal Pernambuco, quaternary
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Siemes, Rutger, Trang Minh Duong, Pim Willemsen, Bas Borsje, and Suzanne Hulscher. "ESTUARINE-WIDE SEDIMENT DYNAMICS UNDER HUMAN INTERVENTIONS AND CLIMATE CHANGE EFFECTS; AN IDEALISED MODEL STUDY." Coastal Engineering Proceedings, no. 37 (September 1, 2023): 12. http://dx.doi.org/10.9753/icce.v37.sediment.12.
Full textAbstract:
Estuaries worldwide are under constant anthropogenic pressure. They are susceptible to climate change effects, from the sea (sea level rise, changing wave climate) and from the river-side (changing river discharge). Besides, estuaries are channelised and embanked to improve flood safety and to reclaim land, and channels are deepened to allow bigger ships to enter the ports. To optimise estuarine functions and sustainably prepare for future challenges, improved understanding of estuarine sediment dynamics after potential changes in the systems configuration and forcings is desired. This paper aims to assess the annual sediment dynamics of an estuary under a climate change effects, and how this is affected by human interventions.