Phosphorus fractionation distribution in Guapimirim estuary: SE Brazil.

Science.gov (United States)

Vicente, Michel Arthur Faria; de Melo, Gustavo Vaz; Baptista Neto, José Antonio; de Oliveira, Allan Sandes

2016-01-01

The Guapimirim estuary is the main tributary of Guanabara bay and is located in the northeast portion. Although it is protected, this estuary has been experiencing strong anthropogenic pressure, which has led to changes in the natural characteristics. Large amounts of sewage are dumped into the bay through tributaries, thereby changing the water and bottom sediment quality. One of the main elements of sewage is phosphorus. Despite its importance to life, a high concentration of this nutrient in the environment can result in eutrophication. This work describes the phosphorus distribution in its different fractions in the bottom sediment at 16 stations located in the main channel of the Guapimirim estuary. These results are correlated with data on grain size, organic matter and calcium carbonate content in the bottom sediment and with physicochemical parameters of the bottom water. The grain size decreases toward the mouth of the estuary, whereas the organic matter and carbonate content increase. The salinity increases significantly at 3.5 km upstream from the mouth, where there is also a notable increase in fine sediments; the same site is the mean position of the salinity front. The temperature and pH increase in the same direction. The Pinorg-total ranges between 3.18 and 7.13 µmol g(-1), increasing toward the mouth. The same trend is observed for the other phosphorus fractions P-Ca, P-Fe and P-f.a., which range from 0.68 to 1.91, 0.79 to 1.71 and 0.03 to 0.93 µmol g(-1), respectively. The P-Ca and P-Fe fractions are the most representative in the Pinorg-total, occurring at 26.3 and 26.0 %, respectively.

Apresentação Workshop Baía de Guanabara

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Claudia Gutteres Vilela

2003-01-01

Full Text Available Ano 2003 Volume 26 - Workshop Baía de Guanabara Editor: Ismar de Souza Carvalho Coordenadora: Claudia Gutteres Vilela: Apresentação ISSN: 0101-9759 É com grande prazer que participo da edição do Anuário de 2003 do Instituto de Geociências, que inclui os trabalhos apresentados no Workshop Baía, realizado nos dias 12 e 13 de novembro de 2002, nesta instituição. O sucesso desse evento deve-se em grande parte aos trabalhos, apresentados sob a forma de palestras em mesas redondas ou painéis, por pesquisadores consagrados no Brasil e no exterior. O conteúdo dos trabalhos possui uma abrangência que se estende desde a Geologia até a Biologia, passando pela Oceanografia e Geografia, sempre com o objetivo comum de reunir dados sobre a Baía de Guanabara visando o diagnóstico ambiental. O Workshop Baía congregou diversas linhas de pesquisa desenvolvidas na Baía de Guanabara e regiões adjacentes, procurando uma integração das mesmas. Deste modo alguns trabalhos caracterizaram, em um contexto mais geral, a evolução do nível do mar na região sudeste durante o Holoceno, bem como apresentaram a neotectônica da região. Geoquímica orgânica de hidrocarbonetos e de metais pesados, sedimentologia e hidrogeologia integraram-se à distribuição de microorganismos nos sedimentos e na água, analisando diversas respostas a diferentes graus de poluição em regiões distintas. Um zoneamento ambiental ofereceu uma visão dinâmica das condições naturais e sociais do conjunto da Baía de Guanabara. A importância do workshop deve-se à busca de uma integração maior dos trabalhos acadêmicos para aplicação à gestão do desenvolvimento sustentável da Baía de Guanabara e seu entorno, que abriga a cidade do Rio de Janeiro e se constitui em uma das regiões com maior índice demográfico do Brasil. Seu impacto pode se avaliado pela presença de representantes de órgãos públicos como a SERLA, a Prefeitura de Niterói e ONGs ligadas a

Lixo flutuante na Baía de Guanabara: passado, presente e perspectivas para o futuro

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Dandara Bernardino

2016-08-01

Full Text Available The pollution of marine and coastal environments by floating litter is a serious problem around the world, usually provoked by an inefficient waste management in the coastal areas, that may generate severe impacts in the wild life, for example death by waste ingestion. The present study has the goal to analyse, under a historical retrospective and future perspective, the floating litter problem at Guanabara’s Bay. Therefore, the methodology for the historical analysis was done by a literature study. In turn, the present analysis was based on field data related to the floating litter on previous studies at the beaches of Icaraí, Charitas and São Francisco located at the city of Niterói, Flamengo beach on Rio de Janeiro and at the Mangrove of Barão de Mauá City’s Natural Park in Magé, respectively. Where samples were collected and current information about the actions related to the floating litter studied. The future perspectives were based on sanitation plans of municipalities around Guanaraba Bay that settle future goals to the pollution of it. In doing so, the results show that in spite of the public agencies efforts to depollute the Guanabara Bay, all the wastes produced by the surrounding municipalities keep reaching the estuary. It is worth mentioning that is too early to determine if these programs will be, in fact, effective and there are many different actions that need to be done including not only social awareness, but also the participation of all the social actors involved.

Epidemiologia da raiva humana na Guanabara

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Alfredo R. Matta B. da Silva

1971-08-01

Full Text Available A raiva humana se mantém como problema de Saúde Pública, especialmente nas áreas urbanas, onde o cão atua como principal reservatório e fonte imediata de infecção. A deficiência de programas de controle de cães vadios, de imunização sistemática e de educação sanitária, contribui para a perpetuação da cadeia epidemiológioa. O presente estudo analisa todos os casos de raiva humana, observados em habitantes do Estado da Guanabara, no período 1965-1969, segundo as variáveis: idade, sexo, côr, variação estacional, período de incubação e de duração da fase clínica, fonte de infecção, local de mordedura e uso de vacina posterior à exposição. Os principais resultados foram: 1. A ravia na Guanabara, parece ser mais comum nos grupos etários mais jovens e nos homens. 2. Não se observou variação estacional. 3. O período de incubação mediano foi de 45 dias e de duração da fase clínica de 3 dias. 4. Ocorreu uma associação entre período de incubação menor e vacinação incompleta.

Distinct responses of bacterial communities to agricultural and urban impacts in temperate southern African estuaries

Science.gov (United States)

Matcher, G. F.; Froneman, P. W.; Meiklejohn, I.; Dorrington, R. A.

2018-01-01

Worldwide, estuaries are regarded as amongst the most ecologically threatened ecosystems and are increasingly being impacted by urban development, agricultural activities and reduced freshwater inflow. In this study, we examined the influence of different human activities on the diversity and structure of bacterial communities in the water column and sediment in three distinct, temperate permanently open estuarine systems within the same geographic region of southern Africa. The Kariega system is freshwater-deprived and is considered to be relatively pristine; the Kowie estuary is marine-dominated and impacted by urban development, while the Sundays system is fresh-water dominated and impacted by agricultural activity in its catchment. The bacterial communities in all three systems comprise predominantly heterotrophic species belonging to the Bacteroidetes and Proteobacteria phyla with little overlap between bacterioplankton and benthic bacterial communities at the species level. There was overlap between the operational taxonomic units (OTUs) of the Kowie and Kariega, both marine-influenced estuaries. However, lower species richness in the Kowie, likely reflects the impact of human settlements along the estuary. The dominant OTUs in the Sundays River system were distinct from those of the Kariega and Kowie estuaries with an overall decrease in species richness and evenness. This study provides an important snapshot into the microbial population structures of permanently open temperate estuarine systems and the influence of anthropogenic impacts on bacterial diversity and community structure.

Indirect Effects and Potential Cumulative Impacts of Dredging in an Urbanized Estuary

Science.gov (United States)

Sommerfield, C. K.; Chen, J.; Ralston, D. K.; Geyer, W. R.

2016-02-01

For over two centuries, the Delaware River and Bay estuary has supported one of the most economically important ports in the United States. To accommodate ships of ever-increasing size, the 165-km axial shipping channel has been deepened to over twice the natural depth of the estuary. While it is known that the channel has modified tides and sedimentation patterns in the estuary, unknown are the impacts on the ecosystem as a whole. A concern is the influence of channelization on sediment movement to the tidal wetland coast, which is eroding at rates on the order of meters per year. Tidal wetlands frame the entire estuary and provide vital ecosystem services ranging from recreation to carbon sequestration. To identify shifts in baseline conditions, we are performing a retrospective analysis of estuarine dynamics using historical bathymetry, numerical modeling, and observational studies. The period of interest extends from 1848 (50 years prior to channel construction) to present. During this period the channel was progressively deepened from its natural depth of 5.5 m to the current depth of 14 m. Preliminary modeling results support independent evidence that the salt intrusion and zone of rapid sediment deposition migrated several 10s of kilometers up-estuary as an indirect effect of deepening. Ironically, the locus of intense deposition now falls squarely within the Wilmington-Philadelphia port complex; river sediment that initially settles in this area is removed by maintenance dredging before it can disperse seaward. Sediment budgetary analysis indicates that the mass of sediment dredged from the upper estuary on average exceeds the mass of the new sediment supplied from the drainage basin. Hence, a probable cumulative impact of dredging is a reduction in sediment delivery to the lower estuary and fringing wetlands. Connections among the shipping channel, wave-tide interactions, and marsh edge erosion are a topic of ongoing modeling and observational research.

Impact of climate change on Gironde estuary

International Nuclear Information System (INIS)

Laborie, Vanessya; Hissel, Francois; Sergent, Philippe

2014-01-01

Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. A numerical model of the Gironde Estuary was used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the 21. century using ONERC's pessimistic scenario for sea level rise (60 cm). The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon,, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the flood plain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the flood plain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results. (authors)

Impact of multiple stressors on juvenile fish in estuaries of the northeast Pacific.

Science.gov (United States)

Toft, Jason D; Munsch, Stuart H; Cordell, Jeffery R; Siitari, Kiira; Hare, Van C; Holycross, Brett M; DeBruyckere, Lisa A; Greene, Correigh M; Hughes, Brent B

2018-05-01

A key step in identifying global change impacts on species and ecosystems is to quantify effects of multiple stressors. To date, the science of global change has been dominated by regional field studies, experimental manipulation, meta-analyses, conceptual models, reviews, and studies focusing on a single stressor or species over broad spatial and temporal scales. Here, we provide one of the first studies for coastal systems examining multiple stressor effects across broad scales, focused on the nursery function of 20 estuaries spanning 1,600 km of coastline, 25 years of monitoring, and seven fish and invertebrate species along the northeast Pacific coast. We hypothesized those species most estuarine dependent and negatively impacted by human activities would have lower presence and abundances in estuaries with greater anthropogenic land cover, pollution, and water flow stress. We found significant negative relationships between juveniles of two of seven species (Chinook salmon and English sole) and estuarine stressors. Chinook salmon were less likely to occur and were less abundant in estuaries with greater pollution stress. They were also less abundant in estuaries with greater flow stress, although this relationship was marginally insignificant. English sole were less abundant in estuaries with greater land cover stress. Together, we provide new empirical evidence that effects of stressors on two fish species culminate in detectable trends along the northeast Pacific coast, elevating the need for protection from pollution, land cover, and flow stressors to their habitats. Lack of response among the other five species could be related to differing resistance to specific stressors, type and precision of the stressor metrics, and limitations in catch data across estuaries and habitats. Acquiring improved measurements of impacts to species will guide future management actions, and help predict how estuarine nursery functions can be optimized given anthropogenic

The impacts of the Samarco mine tailing spill on the Rio Doce estuary, Eastern Brazil.

Science.gov (United States)

Gomes, Luiz Eduardo de Oliveira; Correa, Lucas Barreto; Sá, Fabian; Neto, Renato Rodrigues; Bernardino, Angelo Fraga

2017-07-15

Over 50 million cubic meters of mining tailings were released in the Rio Doce basin after the collapse of the Fundão dam (Samarco) in November 2015. Predicting significant impacts on the Rio Doce estuary, we sampled sediments to investigate short-term impacts on the benthic assemblages and trace metal accumulation on estuarine sediments. With the arrival of the tailing plumes in the estuary, we detected a predominance of clay particles and increased trace metal concentrations of up to 5 times in some areas. The rapid sedimentation after the impact also impacted estuarine macrofaunal assemblages through loss surface-dwelling taxa. As expected, the impacts on benthic assemblages observed up to 3days after the arrival of tailings were not clearly associated with trace metal concentrations, but long-term effects need to be studied. We recommend that the high spatial variability within the estuary be considered in future impact assessment studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Climate Ready Estuaries

Science.gov (United States)

Information on climate change impacts to different estuary regions, tools and resources to monitor changes, and information to help managers develop adaptation plans for risk management of estuaries and coastal communities.

Tendências epidemiológicas do tétano registrado na Guanabara, 1960-1969

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Sérgio Koifman

1974-02-01

Full Text Available A análise dos dados relativos à morbomortalidade do tétano registrado na Guanabara, 1960-1969, concluiu pelo acentuado decréscimo destes índices. Identificaram-se certas medidas adotadas que se relacionam a tal decréscimo. Observou-se que determinada população considerada de alto risco comporta-se como demanda não-satisfeita, sendo um fator limitante ao controle do tétano.Un analisis de los datos relativos a la morbilidad y mortalidad del tétano reportado en el Estado da Guanabara, en el periodo 1960-1969, concluyo sobre la existência de un acentuado decrecimo de estos indices. Fusron identificadas algunas medidas adoptadas en relacion al decrecimo mencionado, observando-se además que grupos poblacionales considerados de alto riesgo fueron identificados como demanda no satisfecha, llmitante en el control de la enfermedad.The morbility and mortality rates for tetanus for the Estado da Guanabara during the period 1960-1969 were analysed. They revealed a marked decrease during that period. Some measures adopted in relation to tetanus, that contributed to this decrease, were identified. It was observed that a population considered as a high-risk population corresponded to an unattended demand. That was a limiting factor in tetanus control.

Thermal impact assessment of multi power plant operations on estuaries

International Nuclear Information System (INIS)

Eraslan, A.H.; Kim, K.H.; Harris, J.L.

1977-01-01

The assessment of the thermal impact of multi power plant operations on large estuaries requires careful consideration of the problems associated with: re-entrainment, re-circulation, thermal interaction, delay in the attainment of thermal equilibrium state, and uncertainty in specifying open boundaries and open boundary conditions of the regions, which are critically important in the analysis of the thermal conditions in receiving water bodies with tidal dominated, periodically reversing flow conditions. The results of an extensive study in the Hudson River at Indian Point, 42 miles upstream of the ocean end at the Battery, concluded that the tidal-transient, multi-dimensional discrete-element (UTA) thermal transport models (ESTONE, FLOTWO, TMPTWO computer codes) and the near-field far-field zone-matching methodology can be employed with a high degree of reliability in the assessment of the thermal impact of multi power plant operations on tidal dominated estuaries

Impact of climate change on Gironde Estuary

Science.gov (United States)

Laborie, Vanessya; Hissel, François; Sergent, Philippe

2014-05-01

Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A numerical model of the Gironde Estuary was then used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the XXIst century using ONERC's pessimistic scenario for sea level rise (60 cm). The model was fed by several data sources : wind fields at Royan and Mérignac interpolated from the grid of the European Climatolologic Model CLM/SGA, a tide signal at Le Verdon, the discharges of Garonne (at La Réole), the Dordogne (at Pessac) and Isle (at Libourne). A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the floodplain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the floodplain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results.

Sea-level Rise Impacts on Oregon Estuaries: Biology and Hydrology

Science.gov (United States)

Estuaries are transitional ecosystems located at the margin of the land and ocean and as a result they are particularly sensitive to sea level rise and other climate drivers. In this presentation, we summarize the potential impacts of sea level rise on key estuarine habitats inc...

Intra-metropolitan inequalities in Rio de Janeiro and the Guanabara Bay cleaning programme

DEFF Research Database (Denmark)

Ribeiro, Gustavo; Silva, Victor

2005-01-01

This paper investigates the impacts of the Guanabara Bay Cleaning Programme (GBCP) on the Rio de Janeiro urban development process. Based on the magnitude of the budget of the programme (HOW MUCH?) and its relevance to the improvement of the life quality of urban dwellers, the main discussion...... of this paper focuses on the role of GBCP in the context of the Rio de Janeiro urban trends and intra-metropolitan inequality dynamics. In studying the impact of the GBCP, we present: (a) a description of the GBCP intervention process and its goals, (b) a spatial analysis of the Rio de Janeiro Metropolitan Area...... the role of the GBCP implementation in the spatial distribution of these patterns throughout these 10 years. The conclusion builds on an analysis of the GBCP role in the current urban development process of the Rio de Janeiro Metropolitan Area, identifying its influences on the dynamics of intra...

Reproductive biology of Cetengraulis edentulus (Cuvier, 1829, the major fishery resource in Guanabara Bay, Brazil

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Ana Clara Sampaio Franco

Full Text Available Cetengraulis edentulus is a broadely distributed engraulid in Southwest Atlantic, currently accounting for the main fish species commercially exploited at Guanabara Bay, Brazil. This study aimed to extend the knowledge on reproduction of C. edentulus at Guanabara Bay and to test whether some descriptors of reproductive activity, especially the gonadosomatic index (GSI, and the index of reproductive activity (IRA changed among seasons. A total of 978 C. edentulus specimens were retrieved from purse seine commercial landings at Conservas Rubi S.A. company, in São Gonçalo city, RJ. Subsamples of 90-120 individuals were collected from bimonthly yields between July 2010 (winter and June 2011 (autumn. Most fish were adults (120-170 mm TL, in response to the high selectivity of commercial fisheries. All descriptors indicated a broad spawning period (late winter to spring, peaking in November, suggesting this is the critical period to protect C. edentulus stocks from overfishing at Guanabara Bay. Fecundity averaged 12,720 oocytes and was positively related to fish size, GSI and fullness index, indicating that preserving larger individuals (TL > 160 mm could contribute significantly to the reproductive success of C. edentulus, since they produce more oocytes. Cetengraulis edentulus é um engraulídeo amplamente distribuído no Atlântico Sudoeste, sendo um importante recurso comercialmente explorado na baía de Guanabara, Brasil. O presente estudo teve como objetivo ampliar o conhecimento sobre a reprodução de C. edentulus na baía de Guanabara e testar quais descritores da atividade reprodutiva, especialmente o índice gonadossomático (IGS e o índice de atividade reprodutiva (IAR se modificaram ao longo das estações do ano. Um total de 978 indivíduos de C. edentulus foram capturados pelo método de rede de cerco da frota comercial no cais da empresa Conservas Rubi S.A., na cidade de São Gonçalo, RJ. Subamostras de 90-120 indivíduos de C

Study of heavy metal concentration and partitioning in the Estrela River: implications for the pollution in Guanabara Bay - SE Brazil

OpenAIRE

Carlos M. A. Rangel; José A. Baptista Neto; Estefan M. Fonseca; John McAlister; Bernard J. Smith

2011-01-01

In this study, the geochemical analysis of ten sediment samples collected along the fluvial system of the Estrela River, which flows into the northern portion of Guanabara Bay, shows the presence of anthropogenic impacts in this area. Concentrations of Fe, Mn, Zn, Cu, Pb, Cr and Ni obtained were slightly higher, when compared with values found innatural environments. The particle size and organic matter content in most of the analyzed stations showed featuresnot conducive to the accumulation ...

The link between water quality and tidal marshes in a highly impacted estuary.

Science.gov (United States)

Meire, Patrick; Maris, Tom; van Damme, Stefan; Jacobs, Sander; Cox, Tom; Struyf, Eric

2010-05-01

The Schelde estuary is one of the most heavily impacted estuaries in Europe. During several decades, untreated waste water from large cities (e.g. Brussels, Antwerp, Valenciennes, Lille) and industries was discharged in the river. As a result, the Schelde estuary has the reputation of being one of the most polluted estuaries in Europe. For a long time (approx. 1950 - 1995) all forms of higher life (macro-invertebrates and fish) were absent in the fresh and brackish parts of the estuary. Due to European legislation, a large part of the sewage water is now treated resulting in a significant recovery of water quality in the estuary. However, next to water quality, the estuary also suffered serious habitat losses during the last decades, mostly due to economic development and changing hydrological conditions causing more erosion. Over the last fifteen years, the management of the estuary has changed fundamentally. It is now more and more focused on the restoration of ecosystem services. In this presentation we will document the changes in water quality over the last 50 years and summarize recent work on the role of tidal marshes on water quality within the freshwater part of the Schelde estuary. Our results stress the important of taking into account ecosystem services and habitat restoration for long-term estuarine management. .After decades of high inorganic nutrient concentrations and recurring anoxia and hypoxia, we observed a paradoxical increase in chlorophyll-a concentrations with decreasing nutrient inputs, indicating a regime shift. Our results indicate that the recovery of a hypereutrophied systems towards a classical eutrophied state, needs the reduction of waste loads below certain thresholds. Paradoxically, phytoplankton production was inhibited by high ammonia or low oxygen concentrations. The system state change is accompanied by large fluctuations in oxygen concentrations. The improved water quality resulted in a remarkable recovery of different groups

Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

International Nuclear Information System (INIS)

Muttray, Annette; Reinisch, Carol; Miller, Jason; Ernst, William; Gillis, Patricia; Losier, Melanie; Sherry, James

2012-01-01

Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ß-endosulfan and α-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: ► We examined leukemia prevalence in PEI clams Mya arenaria. ► Prevalence was generally higher downstream of high intensity

ESTUDO GEOAMBIENTAL DAS CONCENTRAÇÕES DE HIDROCARBONETOS DE PETRÓLEO (POLICÍCLICOS AROMÁTICOS – HPAs AO LONGO DO RIO ESTRELA, BAÍA DE GUANABARA – RJ

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Carlos Marclei Arruda Rangel

2013-02-01

Full Text Available RESUMO Neste estudo, análises geoquímicas de dez amostras de sedimentos coletados ao longo do sistema fluvial do Rio Estrela, localizado ao norte da Baía de Guanabara, evidenciam a presença de impactos antropogênicos nesta área. As concentrações de hidrocarbonetos policíclicos aromáticos (HPAs obtidas mostraram-se ligeiramente elevadas, quando comparadas com valores encontrados em ambientes naturais. Os HPAs foram analisados nos sedimentos ao longo da bacia do Rio Estrela. Embora as concentrações destes compostos detectados nesta área tenham ocorrido em baixas proporções, os tipos de HPAs detectados com alto peso molecular, são mutagênicos e carcinogênicos. Por esta razão, compreender a dinâmica de transporte, deposição e riscos ambientais dos HPAs para o sistema ecológico, especialmente para o sistema aquático, são importantes formas de monitoramento deste ambiente. Palavras chaves: Rio Estrela, Baía de Guanabara, Poluição, HPAs   ABSTRACT In this study, the geochemical analysis of ten sediments samples collected along the fluvial system of the Estrela River, located in the northern portion of Guanabara Bay, shows the presence of anthropogenic impacts in this area. Concentrations of polycyclic aromatic hydrocarbons (PAHs obtained were slightly higher when compared with values found in natural environments. The PAHs were tested in sediments along the drainage basin of Estrela River. Although the compounds found in this area have occurred in low proportions, PAHs compounds detected, with high molecular weight, are mutagenic and carcinogenic. For these reason, understanding PAHs transport, fate and environmental risk to ecological system, especially for aquatic ecosystem, are important forms of monitor this environment. Keywords: Estrela River, Guanabara Bay, Pollution, PAHs

Chemical and microbiological characterization of mangrove sediments after a large oil-spill in Guanabara Bay - RJ - Brazil Caracterização química e microbiológica de sedimentos de manguezal após um grande derramamento de óleo na Baia de Guanabara, RJ, Brasil

OpenAIRE

Maria do Carmo Maciel-Souza; Andrew Macrae; Antonia Garcia Torres Volpon; Patrícia Silva Ferreira; Leda Cristina Mendonça-Hagler

2006-01-01

Seventeen months after a 1,3 million L oil spill into Guanabara Bay, analyses of mangrove sediments showed that the three sites closest to the spill remain highly polluted (>10 µg-g-1 polyaromatic hydrocarbons). A fourth site was less polluted, from which most hydrocarbon degrading bacteria were isolated.Dezessete meses após um derramamento de 1,3 milhões de litros de óleo na Baía de Guanabara, análises de sedimento do manguezal mostraram que os três pontos de amostragem mais próximos d...

Fisheries and conflicts in Guanabara Bay, Rio de Janeiro, Brazil

OpenAIRE

Jablonski, Silvio; Azevedo, Alexandre de Freitas; Moreira, Luiz Henrique Arantes

2006-01-01

Despite the magnitude of domestic and industrial pollution, fishery yield registered in several landing points at Guanabara Bay, between April 2001 and March 2002 was slightly over 19,000 tons, corresponding to a value of US$ 4.8 million. When considered only the fish directed to the food market, the total catch amounted to about 6,300 tons and a value of US$ 3.7 million. Only a few fish species reached expressive densities compatible with commercial fisheries. Among small pelagic fish, Atlan...

Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

Energy Technology Data Exchange (ETDEWEB)

Muttray, Annette, E-mail: amuttray@rescan.com [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Reinisch, Carol, E-mail: creinisch@mbl.edu [Visiting Scientist Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Miller, Jason, E-mail: j.miller@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Ernst, William, E-mail: bill.ernst@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 45 Alderney Drive, Dartmouth, NS, Canada B2Y 2N6 (Canada); Gillis, Patricia, E-mail: patty.gillis@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Losier, Melanie, E-mail: melanie.losier@ec.gc.ca [Environment Canada, Atlantic Laboratory for Environmental Testing, Environmental Science Centre, P.O. Box 23005 Moncton, NB, Canada E1A 6S8 (Canada); Sherry, James, E-mail: jim.sherry@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada)

2012-05-01

Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ss-endosulfan and {alpha}-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: Black-Right-Pointing-Pointer We examined leukemia prevalence in PEI clams Mya arenaria. Black

Differences in the structure of copepod assemblages in four tropical estuaries: Importance of pollution and the estuary hydrodynamics.

Science.gov (United States)

Araujo, Adriana V; Dias, Cristina O; Bonecker, Sérgio L C

2017-02-15

We examined the relationship between pollution and structure of copepod assemblages in estuaries, using sampling standardization of salinity range to reduce the effects of "Estuarine Quality Paradox". Copepod assemblages were analyzed in four Southeast Brazilian estuaries with different water quality levels and different hydrodynamic characteristics. The pollution negatively impacted the descriptors of the assemblage structure. The distribution of structure of copepod assemblages also showed a main separation trend between the most polluted estuaries and those less polluted. Temperature was the main factor affecting the assemblage structuring in the four estuaries. This factor acted in synergism with the effects of pollution impact and physical characteristics of the estuaries on the structure of copepod assemblages, supporting the potential vulnerability of coastal environments due to nutrient enrichment associated with climate change. Our study demonstrated the importance of sampling standardization of the salinity range in estuaries for reliable analysis of pollution effects on biota. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Review of Use of GIS for the Evaluation of Heavy Metal and Water Quality Parameters in the Canal do Cunha Watershed and west of the Guanabara Bay, Rio de Janeiro (Brazil

Directory of Open Access Journals (Sweden)

Renata Coura Borges

2016-06-01

Full Text Available As well as other sub-basins of the Guanabara Bay, the Canal do Cunha watershed, located in the Rio de Janeiro city, has suffered severe environmental degradation since the 50s, due to accelerated urban-industrial development. The fluvial dynamics has changed by the deforestation, landfill constructions, drainage and vale occupation. Canal do Cunha deliver wastewaters and sediments at the western side of Guanabara Bay. Contribute to the environmental degradation and has direct influence on the water quality indexes and heavy metal contamination at the western side of Guanabara Bay. This study intends to evaluate, through geoprocessing techniques, the spatial distribution of Lead (Pb, Zinc (Zn, dissolved oxygen (DO and total phosphorus (total P concentrations and pH values, using data provided by six monitoring stations of the Instituto Estadual do Ambiente – INEA (State Environmental Institute. This work allows to observe the influence of weather conditions on Pb and Zn concentrations in superficial waters and surface sediments and the behavior of DO, pH and total P of superficial waters before and after the implementation of the remediation program: Programa de Despoluição da Baía de Guanabara (PDBG; Pollution Remediation Program of Guanabara Bay. Canal do Cunha flow has direct influence on the low quality indexes of water and contributes to the heavy metal contamination and environmental degradation of the western region of Guanabara Bay.

Impact of intertidal area characteristics on estuarine tidal hydrodynamics: A modelling study for the Scheldt Estuary

Science.gov (United States)

Stark, J.; Smolders, S.; Meire, P.; Temmerman, S.

2017-11-01

Marsh restoration projects are nowadays being implemented as ecosystem-based strategies to reduce flood risks and to restore intertidal habitat along estuaries. Changes in estuarine tidal hydrodynamics are expected along with such intertidal area changes. A validated hydrodynamic model of the Scheldt Estuary is used to gain fundamental insights in the role of intertidal area characteristics on tidal hydrodynamics and tidal asymmetry in particular through several geomorphological scenarios in which intertidal area elevation and location along the estuary is varied. Model results indicate that the location of intertidal areas and their storage volume relative to the local tidal prism determine the intensity and reach along the estuary over which tidal hydrodynamics are affected. Our model results also suggest that intertidal storage areas that are located within the main estuarine channel system, and hence are part of the flow-carrying part of the estuary, may affect tidal hydrodynamics differently than intertidal areas that are side-basins of the main estuarine channel, and hence only contribute little to the flow-carrying cross-section of the estuary. If tidal flats contribute to the channel cross-section and exert frictional effects on the tidal propagation, the elevation of intertidal flats influences the magnitude and direction of tidal asymmetry along estuarine channels. Ebb-dominance is most strongly enhanced if tidal flats are around mean sea level or slightly above. Conversely, flood-dominance is enhanced if the tidal flats are situated low in the tidal frame. For intertidal storage areas at specific locations besides the main channel, flood-dominance in the estuary channel peaks in the vicinity of those areas and generally reduces upstream and downstream compared to a reference scenario. Finally, the model results indicate an along-estuary varying impact on the tidal prism as a result of adding intertidal storage at a specific location. In addition to known

Earthquake and human impact on the sedimentology and geochemistry of Ahuriri Estuary, Hawke's Bay

International Nuclear Information System (INIS)

Chague-Goff, C.; Nichol, S.L.; Ditchburn, R.G.; Trompetter, W.J.; Sutherland, V.T.

1998-01-01

Three cores were collected from the intertidal and salt marsh sediments in Ahuriri Estuary, Hawke's Bay, and analysed by sedimentological, chemical and geochronological techniques. Signatures of various events, of both natural and anthropogenic origin, were identified. Evidence for the 1931 Hawke's Bay earthquake, which resulted in an uplift of one to two metres in the Napier area, is given by a change in grainsize distribution in a core from the southern shore of the Lower Estuary. The change to a high energy environment, similar to the present one in the Lower Estuary, has resulted in deposition of sand over fine silt. The data suggest increased sediment accumulation rates following the uplift event, which might be attributed to increased erosion in the upper catchment. There is no evidence of the earthquake at the two other sites sampled, which is probably due to their more sheltered location in the estuary. Post-European settlement impact is mainly restricted to the Lower Estuary, where increased concentrations of Zn, Cr, Pb and Cu may be due to industrial discharges. Evidence of agricultural runoff is given by an increase in Cu concentrations near the Poraiti Hills. The chemical data (Cl and S) suggest a change in the depositional environment in the Upper Estuary due to increased freshwater influx and/or decrease in seawater influence. Dating by 210 Pb infers that this occurred prior to 1931, but the origin and timing of the event are still to be determined. Sediment accumulation rates have averaged 2.5 mm/yr for the last 45 years in the Lower Estuary and 3.8 mm/yr for the last 70 years or so in the Upper Estuary. The variation probably reflects the difference in depositional environment, from a high energy environment dominated by tidal and wave action to a low energy environment with additional organic and fine sediment input from stream runoff. The various signatures identified are based on known events but may be used for identifying events in other less

Recruitment success and growth variability of mugilids in a West African estuary impacted by climate change

Science.gov (United States)

Trape, S.; Durand, J.-D.; Vigliola, L.; Panfili, J.

2017-11-01

With the persistence of a drought since the late 1960s, some West African estuaries became permanently reversed in term of salinity gradient and hypersaline waters are present in their upstream part (salinity >60). To understand the mechanisms regulating fish recruitment intensity in these estuaries and evaluate the consequences of freshwater shortages on juvenile habitat quality, a growth study was conducted in the Saloum hypersaline estuary (Senegal). The Mugilidae fish family, highly representative of estuarine environments, was targeted and several species sampled (Chelon dumerili, Mugil bananensis and M. cf. curema sp. M). Juveniles were sampled monthly all the year round in three areas of the estuary exhibiting strongly contrasted habitat conditions. Otolith sections were used to estimate the ages, reconstruct growth trajectories, estimate the duration of the oceanic larval phase, and evaluate juvenile growth variability along the salinity gradient. Analyses revealed that the temporal recruitment variability of C. dumerili, with 2 annual cohorts, was not mainly induced by growth-selection mechanisms, but probably more by predation pressures. Juveniles exhibited significantly faster growth rates in the lower salinity suggesting that benthic food availability was a strong factor controlling habitat quality of early juveniles. Salinity had also a clear impact when reducing the growth in hypersaline conditions and/or selecting slower growing individuals. Moderate freshwater inputs positively affected the nursery function of the estuary for mugilids by enhancing the productivity of the first trophic levels. In a long term, the global change could have an impact of the mugilid fishery and its management.

Leven estuary project. Fisheries Department final report

OpenAIRE

Bayliss, B.D.

1997-01-01

This is the report on the Leven estuary project: Fisheries Department final report produced by the Environment Agency North West in 1997. This report contains information about Leven estuary, river Leven catchment, river Crake catchment and the Ulverston Discharges. The Leven estuary is characterised by being very shallow, and shares the extremely variable tides and currents that characterize the whole of Morecambe Bay. There was little detailed knowledge of the impact on the Leven estuary, a...

Impact of boat generated waves over an estuarine intertidal zone of the Seine estuary (France)

Science.gov (United States)

Deloffre, Julien; Lafite, Robert

2015-04-01

Water movements in macrotidal estuaries are controlled by the tidal regime modulated seasonally by the fluvial discharge. Wind effect on hydrodynamics and sediment transport is also reported at the mouth. Besides estuaries are frequently man altered our knowledge on the human impact on hydrodynamics and sediment transport is less extended. As an example on the Seine estuary (France) port authorities have put emphasis on facilitating economic exchanges by means of embankment building and increased dredging activity over the last century. These developments led to secure sea vessel traffic in the Seine estuary but they also resulted in a change of estuarine hydrodynamics and sediment transport features. Consequences of boat generated waves are varied: increased water turbidity and sediment transfer, release of nutrient and contaminants in the water column, harmful to users, ecosystems and infrastructures generating important maintenance spending. The aim of this study is to analyse the impact of boat generated waves on sediment transport over an intertidal area. The studied site is located on the left bank in the fluvial part of the Seine estuary. On this site the maximum tidal range ranges between 1.25 and 3.5m respectively during neap and spring tide. The sampling strategy is based on continuous ADV acquisition at 4Hz coupled with turbidimeter and altimeter measurements (1 measurement every minute) in order to decipher sediment dynamics during one year. Our results indicate that sediment dynamics are controlled by river flow while medium term scale evolution is dependent on tidal range and short term dynamics on sea-vessels waves. 64% of boat passages generated significant sediment reworking (from few mm.min-1 to 3cm.min-1). This reworking rate is mainly controlled by two parameters: (i) water height on the site and (ii) vessels characteristics; in particular the distance between seabed and keel that generate a Bernoulli wave (with maximum amplitude of 0.6m

Aragonite saturation state in a tropical coastal embayment dominated by phytoplankton blooms (Guanabara Bay - Brazil).

Science.gov (United States)

Cotovicz, Luiz C; Knoppers, Bastiaan A; Brandini, Nilva; Poirier, Dominique; Costa Santos, Suzan J; Abril, Gwenaël

2018-04-01

The dynamics of the aragonite saturation state (Ω arag ) were investigated in the eutrophic coastal waters of Guanabara Bay (RJ-Brazil). Large phytoplankton blooms stimulated by a high nutrient enrichment promoted the production of organic matter with strong uptake of dissolved inorganic carbon (DIC) in surface waters, lowering the concentrations of dissolved carbon dioxide (CO 2aq ), and increasing the pH, Ω arag and carbonate ion (CO 3 2- ), especially during summer. The increase of Ω arag related to biological activity was also evident comparing the negative relationship between the Ω arag and the apparent utilization of oxygen (AOU), with a very close behavior between the slopes of the linear regression and the Redfield ratio. The lowest values of Ω arag were found at low-buffered waters in regions that receive direct discharges from domestic effluents and polluted rivers, with episodic evidences of corrosive waters (Ω arag <1). This study showed that the eutrophication controlled the variations of Ω arag in Guanabara Bay. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trace metal contamination in mangrove sediments, Guanabara Bay, Rio de Janeiro, Brazil

OpenAIRE

Farias,Cassia O.; Hamacher,Claudia; Wagener,Angela de Luca R.; Campos,Reinaldo C. de; Godoy,José M.

2007-01-01

The Guanabara Bay in Rio de Janeiro has undergone profound alterations of its natural environmental conditions. Metal concentration increase in sediments has been reported to be among these alterations. Trace-metal contamination and availability were studied in sediments of 3 mangrove areas of the bay. Cd, Zn, Pb, Ni, Cu and Al concentrations were determined in segments of sediment cores, after treatment with 1 mol L-1 HCl and with concentrated HNO3. Fe and Mn were determined in the leach wit...

The Estuary Book: A Guide to Promoting Understanding and Regional Management of Maine's Estuaries and Embayments.

Science.gov (United States)

Ruffing, Jenny

The objective of this document is to provide information about estuaries, the impact of uses on the environmental health of an estuary, and what communities and concerned individuals can do to manage and protect their local estuarine resources successfully. Much of the information presented here pertains to other embayments along the Maine coast…

Occurrence of chlorinated pesticides in mussels of Guanabara Bay, Rio de Janeiro, Brazil

International Nuclear Information System (INIS)

Xavier de Brito, A.P.; De Andrade Bruening, I.M.R.; Moreira, I.; Loureiro, I.

1999-01-01

Present work investigates the contamination of some chlorinated pesticides in common mussels (Perna perna) from the Guanabara Bay. These mussels can be found in several points near the entrance of the Bay, where they either grow naturally or are cultivated by fishermen which make their living of this activity. Five collecting areas were studied and the concentrations of eight pesticides, namely HCB, γ-HCH, total DDT, DDD and DDE, Aldrin, Dieldrin and Endrin were determined

Bacterial production in Guanabara Bay (Rio de Janeiro, Brazil evaluated by ³H-leucine incorporation

Directory of Open Access Journals (Sweden)

Alessandra M. Gonzalez

2000-01-01

Full Text Available The aim of this work was to evaluate the necessary ³H-leucine concentration to estimate bacterial production in Guanabara Bay through saturation curves. A second aim was to collect preliminary data of bacterial production in two distinct sites corresponding to different water qualities: Urca inlet and Governador Island. Saturation curves were made with water samples taken at the main circulation channel of the bay, Paquetá Island, and the two sites mentioned before. The ³H-leucine curves showed similar pattern for all studied areas, indicating the ideal isotope concentration to be 10 nM. Bacterial biomass production ranged from 0.40 to 4.53 µgC L-1 h-1 in Urca and from 3.86 to 73.72 µgC L-1 h-1 in Governador Island indicating the relationship between nutrients and organic matter supply and bacterial productivity. This work is an important reference for studies on trophodynamics, biogeochemical cycles and modelling in Guanabara Bay.O objetivo desse trabalho foi realizar curvas de saturação a fim de otimizar a concentração de ³H-leucina necessária para avaliar produção bacteriana na Baía de Guanabara. Objetivou-se ainda a aquisição de dados preliminares de produção bacteriana em dois locais distintos em termos de qualidade de água : enseada da Urca e Ilha do Governador. As amostras para as curvas foram obtidas na região do Canal Central e na Ilha de Paquetá, além dos dois locais de coleta citados acima. Seguiu-se a metodologia descrita por Kirchman et al. (1985 e modificada por Smith & Azam (1992. As curvas de ³H-leucina mostraram um padrão semelhante para todas as áreas estudadas, indicando a concentração ótima de isótopo de 10 nM. A produção de biomassa bacteriana variou de 0,40 a 4,53 µgC L-1 h-1 na Urca e de 3,86 a 73,72 µgC L-1 h-1 na Ilha do Governador confirmando a relação entre a disponibilidade de nutrientes e matéria orgânica e o aumento da produtividade bacteriana. Essas análises poderão ser

Spatial distribution of pollen grains and spores in surface sediments of Guanabara Bay, Rio de Janeiro, Brazil.

Science.gov (United States)

Barreto, Cintia F; Vilela, Claudia G; Baptista-Neto, José A; Barth, Ortrud M

2012-09-01

Aiming to investigate the deposition of pollen grains and spores in Guanabara Bay, Rio de Janeiro State, 61 surface sediment samples were analyzed. The results showed that the current deposition of palynomorphs in surface sediments of Guanabara Bay represents the regional vegetation of this hydrographic basin. The differential distribution of palynomorphs followed a pattern influenced by bathymetry, tidal currents speed, discharge of numerous rivers, and by human activity. The dominance of representatives of Field Vegetation reflects the changes of the original flora caused by intense human activities in the region. The continued presence and richness of pollen types of rain forest in the samples indicates that their source area might be the vegetation from riparian border of rivers in the western sector of the Bay, where the mangrove vegetation is being preserved. The large amount of damaged palynomorphs may be related to abrasion that occurs during river transport, indicating removal or reworking from their areas of origin.

Sea-level Rise Impacts on Oregon Estuaries: Biology and Hydrology - for posting on website

Science.gov (United States)

Estuaries are transitional ecosystems located at the margin of the land and ocean and as a result they are particularly sensitive to sea level rise and other climate drivers. In this presentation, we summarize the potential impacts of sea level rise on key estuarine habitats incl...

Chemical and microbiological characterization of mangrove sediments after a large oil-spill in Guanabara Bay - RJ - Brazil

OpenAIRE

Maciel-Souza,Maria do Carmo; Macrae,Andrew; Volpon,Antonia Garcia Torres; Ferreira,Patrícia Silva; Mendonça-Hagler,Leda Cristina

2006-01-01

Seventeen months after a 1,3 million L oil spill into Guanabara Bay, analyses of mangrove sediments showed that the three sites closest to the spill remain highly polluted (>10 µg-g-1 polyaromatic hydrocarbons). A fourth site was less polluted, from which most hydrocarbon degrading bacteria were isolated.

Spatial distribution of pollen grains and spores in surface sediments of Guanabara Bay, Rio de Janeiro, Brazil

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Cintia F. Barreto

2012-09-01

Full Text Available Aiming to investigate the deposition of pollen grains and spores in Guanabara Bay, Rio de Janeiro State, 61 surface sediment samples were analyzed. The results showed that the current deposition of palynomorphs in surface sediments of Guanabara Bay represents the regional vegetation of this hydrographic basin. The differential distribution of palynomorphs followed a pattern influenced by bathymetry, tidal currents speed, discharge of numerous rivers, and by human activity. The dominance of representatives of Field Vegetation reflects the changes of the original flora caused by intense human activities in the region. The continued presence and richness of pollen types of rain forest in the samples indicates that their source area might be the vegetation from riparian border of rivers in the western sector of the Bay, where the mangrove vegetation is being preserved. The large amount of damaged palynomorphs may be related to abrasion that occurs during river transport, indicating removal or reworking from their areas of origin.Com objetivo de investigar a deposição dos grãos de pólen e esporos na Baía de Guanabara, Estado do Rio de Janeiro, 61 amostras de sedimentos superficiais foram analisadas. Os resultados mostraram que a deposição atual dos palinomorfos nos sedimentos superficiais da Baía de Guanabara representa a vegetação regional de sua bacia hidrográfica. A distribuição diferencial dos palinomorfos seguiu um padrão influenciado pela batimetria, velocidade das corretes de marés, descarga dos numerosos rios e pela atividade humana. A dominância dos taxa representantes da Vegetação Campestre reflete as mudanças da flora original causadas por intensas atividades humanas na região. A presença contínua e a grande riqueza de tipos polínicos da Floresta Ombrófila nas amostras, indica que a área fonte pode ser a vegetação das bordas dos rios do setor oeste da Baía, onde a vegetação de mangue está sendo preservada. A

Dynamic of decapod crustacean larvae on the entrance of Guanabara bay

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Lohengrin Dias de Almeida Fernandes

2002-12-01

Full Text Available In the present study, we observed seasonal variations in the density of decapod larvae as well as changes in density related to diurnal and tidal cycles. Among the decapod larvae collected, portunids and grapsids were the most abundant, especially during nocturnal ebb tides and near the surface. The same results were obtained in late winter (September and late summer (March. These results demonstrated a flow of decapod larvae from Guanabara Bay to adjacent coastal waters. Luciferid (Lucifer faxoni was the only group with high densities during flood tides and we suggest this is an evidence of L. faxoni larvae entering Guanabara Bay in late winter. Probably these changes in distribution of Lucifer faxoni among winter and summer were related to reproductive cycle in the bay. For the portunids, grapsids and ocypodids, a similar dispersion strategy was observed towards adjacent coastal waters in the surface during nocturnal ebb tides.Larvas de crustáceos decápodes são organismos planctônicos comuns tanto em regiões costeiras rasas como em estuários. Nesse trabalho, foi acompanhada a variação da densidade das larvas de decápodes num ponto estratégico entre a porção interior da baía de Guanabara e a região costeira adjacente. A coleta de grandes quantidades de zoés de braquiúros, principalmente das famílias Portunidae e Grapsidae, na superfície durante as marés de vazante noturnas sugere uma tendência de exportação para a região costeira adjacente. A repetição desse padrão no inverno e no verão demonstrou que as respostas dos organismos às variações de luz e maré não foram alteradas de modo significativo entre as duas estações do ano, exceto para os luciferídeos. O fluxo observado para a única espécie de luciferídeo capturada (Lucifer faxoni foi significativamente diferente entre os dois períodos do ano analisados. É provável que essas diferenças na distribuição de Lucifer faxoni seja relacionada ao ciclo

Impacts of marine renewable energy scheme operation on the eutrophication potential of the Severn Estuary, UK

Science.gov (United States)

Kadiri, Margaret; Kay, David; Ahmadian, Reza; Bockelmann-Evans, Bettina; Falconer, Roger; Bray, Michaela

2013-04-01

In recent years there has being growing global interest in the generation of electricity from renewable resources. Amongst these, marine energy resource is now being considered to form a significant part of the energy mix, with plans for the implementation of several marine renewable energy schemes such as barrages and tidal stream turbines around the UK in the near future. Although marine energy presents a great potential for future electricity generation, there are major concerns over its potential impacts, particularly barrages, on the hydro-environment. Previous studies have shown that a barrage could significantly alter the hydrodynamic regime and tidal flow characteristics of an estuary, with changes to sediment transport (Kadiri et al., 2012). However, changes to nutrients have been overlooked to date. Hence, considerable uncertainty remains as to how a barrage would affect the trophic status of an estuary. This is particularly important because eutrophication can lead to algal toxin production and increased mortality of aquatic invertebrates and fish populations. Therefore, this study examines the impacts of the two different modes of operation of a barrage (i.e. ebb generation and flood-ebb generation) on the eutrophication potential of the Severn Estuary using a simplified model developed by the UK's Comprehensive Studies Task Team (CSTT). The model uses a set of equations and site-specific input data to predict equilibrium dissolved nutrient concentrations, phytoplankton biomass, light-controlled phytoplankton growth rate and primary production which are compared against CSTT set standards for assessing the eutrophic status of estuaries and coastal waters. The estuary volume and tidal flushing time under the two operating modes were estimated using a hydrodynamic model and field surveys were conducted to obtain dissolved nitrate and phosphate concentrations which served as input data. The predicted equilibrium dissolved nitrate and phosphate

Chemical and microbiological characterization of mangrove sediments after a large oil-spill in Guanabara Bay - RJ - Brazil Caracterização química e microbiológica de sedimentos de manguezal após um grande derramamento de óleo na Baia de Guanabara, RJ, Brasil

Directory of Open Access Journals (Sweden)

Maria do Carmo Maciel-Souza

2006-09-01

Full Text Available Seventeen months after a 1,3 million L oil spill into Guanabara Bay, analyses of mangrove sediments showed that the three sites closest to the spill remain highly polluted (>10 µg-g-1 polyaromatic hydrocarbons. A fourth site was less polluted, from which most hydrocarbon degrading bacteria were isolated.Dezessete meses após um derramamento de 1,3 milhões de litros de óleo na Baía de Guanabara, análises de sedimento do manguezal mostraram que os três pontos de amostragem mais próximos do local do acidente permanecem altamente poluídos (>10 µg-g-1 hidrocarbonetos poliaromáticos. Do quarto ponto de amostragem, o menos poluído, foi isolada a maioria das bactérias degradadoras de hidrocarbonetos.

Zooplankton community changes in Nhlabane estuary, South Africa ...

African Journals Online (AJOL)

made impacts since 1977, when the lake and estuary were separated by the construction of a barrage. More recent man-made events included the construction of temporary sand walls, mid-way along the estuary, to allow crossing of a mining ...

Ecosystem changes in the Neva Estuary (Baltic Sea): natural dynamics or response to anthropogenic impacts?

Science.gov (United States)

Golubkov, Sergey; Alimov, Alexander

2010-01-01

The Neva Estuary situated in the eastern Gulf of Finland is one of the largest estuaries of the Baltic Sea with a large conurbation, St. Petersburg, situated on its coast. Eutrophication, alien species and large-scale digging and dumping of bottom sediment are the most prominent anthropogenic impacts on its ecosystem. However, many ecosystem responses, which are traditionally attribute to these impacts, are related to natural dynamics of the ecosystem. Fluctuations in discharge of the Neva River, intrusions of bottom hypoxic waters from the western part of the Gulf of Finland, higher summer temperatures and a shorter period of ice cover are climatic mediated factors inducing adverse changes in its ecosystem from the 1980s onwards. The main ecosystem responses to these factors are 2-3-fold increase of trophic status, deterioration of native zoobenthic communities and establishment of alien species, as well as the many fold decrease of fish catch and the population of ringed seal in the region. Copyright 2010 Elsevier Ltd. All rights reserved.

Multi-timescale sediment responses across a human impacted river-estuary system

Science.gov (United States)

Chen, Yining; Chen, Nengwang; Li, Yan; Hong, Huasheng

2018-05-01

Hydrological processes regulating sediment transport from land to sea have been widely studied. However, anthropogenic factors controlling the river flow-sediment regime and subsequent response of the estuary are still poorly understood. Here we conducted a multi-timescale analysis on flow and sediment discharges during the period 1967-2014 for the two tributaries of the Jiulong River in Southeast China. The long-term flow-sediment relationship remained linear in the North River throughout the period, while the linearity showed a remarkable change after 1995 in the West River, largely due to construction of dams and reservoirs in the upland watershed. Over short timescales, rainstorm events caused the changes of suspended sediment concentration (SSC) in the rivers. Regression analysis using synchronous SSC data in a wet season (2009) revealed a delayed response (average 5 days) of the estuary to river input, and a box-model analysis established a quantitative relationship to further describe the response of the estuary to the river sediment input over multiple timescales. The short-term response is determined by both the vertical SSC-salinity changes and the sediment trapping rate in the estuary. However, over the long term, the reduction of riverine sediment yield increased marine sediments trapped into the estuary. The results of this study indicate that human activities (e.g., dams) have substantially altered sediment delivery patterns and river-estuary interactions at multiple timescales.

Environmental management of a highly impacted, urbanized tropical estuary: rehabilitation and restoration

Science.gov (United States)

Thorhaug, A.

1980-03-01

The principles of the dynamics and interrelationships within the dominant subtropical and tropical Caribbean seagrass community have been studied previously before, during, and after impact. From these and scores of observations of damage and recovery patterns in Thalassia ecosystems, a sense of management recovery strategy has emerged. Artificial restoring of Thalassia testudinum seeds into areas cut off from stock (fruit, seeds) appeared feasible on a large scale after the Turkey Point (Biscayne Bay, Miami, Florida) restoration and test sampling throughout North Biscayne Bay. Two large-scale seeding attempts were made; after 11 months they compared favorably with Turkey Point specimens with regard to growth parameters, despite the turbidity and other persistent pollution. Thus, the possible areas in which Thalassia seed restoration can be used has increased to include estuaries of multiple impact still in various stages of recovery after physical and sewage pollution. This technique should be especially useful to “developing” nations where important nearshore fisheries nurseries based on Thalassia ecosystems have been heavily damaged and now lie barren. Man's impact on the estuary where seed restoration was attempted includes the following activities: 50% of the bay bottom directly dredged or filled (leaving much unconsolidated sediment); 50 million gallons of domestic waste dumped directly into a low flushing part of the bay for 20 years; seven major causeways transecting the bay, restricting circulation and flushing; two artificial inlets made into navigational channels; freshwater sheet flow drastically changed due to channelization by flood-control canals; urban runoff from a million people entering the bay. Most of the impacts have now abated; however, their long-term effects remain.

Trophic flow structure of a neotropical estuary in northeastern Brazil and the comparison of ecosystem model indicators of estuaries

Science.gov (United States)

Lira, Alex; Angelini, Ronaldo; Le Loc'h, François; Ménard, Frédéric; Lacerda, Carlos; Frédou, Thierry; Lucena Frédou, Flávia

2018-06-01

We developed an Ecopath model for the Estuary of Sirinhaém River (SIR), a small-sized system surrounded by mangroves, subject to high impact, mainly by the sugar cane and other farming industries in order to describe the food web structure and trophic interactions. In addition, we compared our findings with those of 20 available Ecopath estuarine models for tropical, subtropical and temperate regions, aiming to synthesize the knowledge on trophic dynamics and provide a comprehensive analysis of the structures and functioning of estuaries. Our model consisted of 25 compartments and its indicators were within the expected range for estuarine areas around the world. The average trophic transfer efficiency for the entire system was 11.8%, similar to the theoretical value of 10%. The Keystone Index and MTI (Mixed Trophic Impact) analysis indicated that the snook (Centropomus undecimalis and Centropomus parallelus) and jack (Caranx latus and Caranx hippos) are considered as key resources in the system, revealing their high impact in the food web. Both groups have a high ecological and commercial relevance, despite the unregulated fisheries. As result of the comparison of ecosystem model indicators in estuaries, differences in the ecosystem structure from the low latitude zones (tropical estuaries) to the high latitude zones (temperate system) were noticed. The structure of temperate and sub-tropical estuaries is based on high flows of detritus and export, while tropical systems have high biomass, respiration and consumption rates. Higher values of System Omnivory Index (SOI) and Overhead (SO) were observed in the tropical and subtropical estuaries, denoting a more complex food chain. Globally, none of the estuarine models were classified as fully mature ecosystems, although the tropical ecosystems were considered more mature than the subtropical and temperate ecosystems. This study is an important contribution to the trophic modeling of estuaries, which may also help

HDPE (High Density Polyethylene) pipeline and riser design in Guanabara Bay: challenges and solutions

Energy Technology Data Exchange (ETDEWEB)

Bomfimsilva, Carlos; Jorge, Joao Paulo Carrijo; Schmid, Dominique; Gomes, Rodrigo Klim [INTECSEA, Sao Paulo, SP (Brazil); Lima, Alexander Piraja [GDK, Salvador, BA (Brazil)

2009-12-19

Worldwide shipments of plastic pipes are forecasted to increase 5.2% per year since 2008, being commonly used for water supply and sewage disposal. The HDPE (High Density Polyethylene) pipes have been applied recently to deliver potable water and fire fighting water for the main pier of the LNG system in Guanabara Bay, Rio de Janeiro. The system contains three sizes of pipe outside diameter, 110 mm and 160 mm for water supply, and 500 mm for the fire fighting system. The main design challenges of the pipeline system included providing on-bottom stability, a suitable installation procedure and a proper riser design. The on-bottom stability calculations, which are quite different from the conventional steel pipelines, were developed by designing concrete blocks to be assembled on the pipeline in a required spacing to assure long term stability, knowing that plastic pipes are buoyant even in flooded conditions. The installation procedure was developed considering the lay down methodology based on surface towing technique. The riser was designed to be installed together with additional steel support structure to allow the entire underwater system to have the same plastic pipe specification up to the surface. This paper presents the main challenges that were faced during the design of the HDPE pipelines for the LNG system in Guanabara Bay, addressing the solutions and recommendations adopted for the plastic underwater pipeline system.

Zooplankton abundance in the River Kars, Northeast Turkey: Impact ...

African Journals Online (AJOL)

PRECIOUS

2009-11-02

Nov 2, 2009 ... Turkey: Impact of environmental variables. H. Özbay1* and ... in the river. Key words: River Kars, zooplankton, running water, environmental factors. ..... tergestina (Branchiopoda: Onychopoda) in Guanabara Bay, Brazil. Braz.

Ecology of estuaries

International Nuclear Information System (INIS)

Kennish, M.J.

1992-01-01

Ecology of Estuaries: Anthropogenic Effects represents the most definitive and comprehensive source of reference information available on the human impact on estuarine ecosystems. The book discusses both acute and insidious pollution problems plaguing these coastal ecotones. It also provides a detailed examination of the deleterious and pervasive effects of human activities on biotic communities and sensitive habitat areas in estuaries. Specific areas covered include organic loading, oil pollution, polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, heavy metals, dredging and dredge-spoil disposal, radionuclides, as well as other contaminants and processes. The diverse components of these anthropogenic influences are assembled in an organized framework and presented in a clear and concise style that will facilitate their understanding

Population structure of the lancelet Branchiostoma caribaeum (Cephalochordata: Branchiostomidae in the Baía de Guanabara, Rio de Janeiro, southeastern Brazil Estrutura populacional do anfioxo Branchiostoma caribaeum (Cephalochordata: Branchiostomidae na Baía de Guanabara, sudeste do Brasil

Directory of Open Access Journals (Sweden)

Luis F. B. da Silva

2008-12-01

Full Text Available Population structure of the lancelet Branchiostoma caribaeum Sandevall, 1853 was studied in four surveys, corresponding to austral seasons, in a tropical bay, southeast of Brazil. Abundance was higher in the spring and was positively correlated to coarse sediments, limiting its occurrence to some sectors of the sampling area. Body length and biomass differed seasonally but not between sexes. Sexually mature individuals occurred in all seasons, suggesting continuous breeding that is typical of tropical species. Variation in the frequency of small specimens indicates temporal differences in the intensity of breeding. The body length of recruits differed from other population of lancelets and the small length which B. caribaeum attained sexual maturity in Guanabara Bay may be related to local environmental stress or the great availability of food.A estrutura populacional do anfioxo Branchiostoma caribaeum Sandevall, 1853 foi analisada em quatro campanhas abrangendo todas as estações do ano, na Baía de Guanabara, sudeste do Brasil. A abundância de indivíduos foi maior na primavera e positivamente correlacionada com sedimentos grossos, tendo sua distribuição limitada a alguns setores da área amostral. O tamanho corpóreo e a biomassa diferiram sazonalmente, mas não entre os sexos. Indivíduos sexualmente maduros ocorreram em todas as estações do ano, sugerindo uma reprodução contínua, típica de espécies tropicais. Variações na freqüência de ocorrência de espécimes pequenos indicaram diferenças temporais na intensidade da reprodução. O tamanho corpóreo dos recrutas diferiu de populações de anfioxos de outros locais. O menor tamanho em que B. caribaeum atinge a maturidade sexual na Baía da Guanabara pode estar relacionada ao estresse ambiental ou à grande disponibilidade de alimento do local.

Tillamook Estuary Case Study: Local Drivers Influencing Coastal Acidification

Science.gov (United States)

US EPA initiated a study in the Tillamook estuary and watershed focused on the impact of changes in watershed land use, ocean conditions, and weather on estuarine water quality and ecosystem goods and services production within the estuary. This project is a collaboration betwee...

Superficial distribution of aromatic compounds and geomicrobiology of sediments from Suruí Mangrove, Guanabara Bay, RJ, Brazil

OpenAIRE

Fontana,Luiz F.; Silva,Frederico S. da; Figueiredo,Natália G. de; Brum,Daniel M.; Netto,Annibal D. Pereira; Gigueiredo Junior,Alberto G. de; Crapez,Mirian A.C.

2010-01-01

The distribution of selected aromatic compounds and microbiology were assessed in superficial sediments from Suruí Mangrove, Guanabara Bay. Samples were collected at 23 stations, and particle size, organic matter, aromatic compounds, microbiology activity, biopolymers, and topography were determined. The concentration of aromatic compounds was distributed in patches over the entire mangrove, and their highest total concentration was determinated in the mangrove's central area. Particle size d...

Northeast Guanabara Bay and coastal plain Holocene sedimentary evolution (Brazil: A contribution

Directory of Open Access Journals (Sweden)

Rodrigo Coutinho Abuchacra

2017-02-01

Full Text Available Sedimentological and radiocarbon investigations are part of an ongoing research on the Bay-head delta of northeast Guanabara Bay, Rio de Janeiro State. Sediment accumulation indicates that the Holocene infill of the bay-head delta started around 8.2 kyr BP and was not in pace with the eustatic sea-level rise. Sediment accumulation was faster during the transgressive phase (0.56 cm.yr-1. However, during the regressive phase, progradation driven by base-level fall was predominant over vertical sediment accumulation (0.02 cm.yr-1. Based on coring, three sedimentary units were defined: fluvial sands (U1, estuarine deposits (U2 and fluvial mud (U3.

West Coast Estuaries for Groundfish Essential Fish Habitat (EFH) Environmental Impact Statement

Data.gov (United States)

Pacific States Marine Fisheries Commission — These data depict the boundaries of estuaries along the West Coast of the United States. The estuary boundaries are delineated according to the U.S. Fish and...

Geomicrobiology of cores from Suruí Mangrove--Guanabara Bay--Brazil.

Science.gov (United States)

Fontana, Luiz Francisco; Mendonça Filho, João Graciano; Netto, Annibal Duarte Pereira; Sabadini-Santos, Elisamara; de Figueiredo, Alberto Garcia; Crapez, Mirian Araújo Carlos

2010-10-01

The aim of this work was to quantify the biopolymers associated to esterase enzymes and identify bacterial respiratory activity in four cores collected in Suruí Mangrove, Guanabara Bay - RJ. Biopolymer concentration was 1000 times lower than previously reported in the literature, indicating the need for creating and establishing eutrophication indicative rates and records compatible with tropical coastal systems. The biochemical representative relationships in the cores were equivalent to those from studies on coastal marine environments made in the Northern Hemisphere. The esterase enzymes in the sediment proved efficient in the mineralization of biopolymers, even with preferentially anaerobic metabolic physiology. Despite the lack of incipient geomicrobiological studies, the results highlighted the possible application of microbiology to a better understanding of geological processes. Copyright © 2010 Elsevier Ltd. All rights reserved.

Nutrients in estuaries - An overview and the potential impacts of climate change

Energy Technology Data Exchange (ETDEWEB)

Statham, Peter J., E-mail: pjs@noc.soton.ac.uk

2012-09-15

The fate and cycling of macronutrients introduced into estuaries depend upon a range of interlinked processes. Hydrodynamics and morphology in combination with freshwater inflow control the freshwater flushing time, and the timescale for biogeochemical processes to operate that include microbial activity, particle-dissolved phase interactions, and benthic exchanges. In some systems atmospheric inputs and exchanges with coastal waters can also be important. Climate change will affect nutrient inputs and behaviour through modifications to temperature, wind patterns, the hydrological cycle, and sea level rise. Resulting impacts include: 1) inundation of freshwater systems 2) changes in stratification, flushing times and phytoplankton productivity 3) increased coastal storm activity 4) changes in species and ecosystem function. A combination of continuing high inputs of nutrients through human activity and climate change is anticipated to lead to enhanced eutrophication in the future. The most obvious impacts of increasing global temperature will be in sub-arctic systems where permafrost zones will be reduced in combination with enhanced inputs from glacial systems. Improved process understanding in several key areas including cycling of organic N and P, benthic exchanges, resuspension, impact of bio-irrigation, particle interactions, submarine groundwater discharges, and rates and magnitude of bacterially-driven recycling processes, is needed. Development of high frequency in situ nutrient analysis systems will provide data to improve predictive models that need to incorporate a wider variety of key factors, although the complexity of estuarine systems makes such modelling a challenge. However, overall a more holistic approach is needed to effectively understand, predict and manage the impact of macronutrients on estuaries. -- Highlights: Black-Right-Pointing-Pointer Estuarine macronutrient behaviour defined by both physical and biogeochemical processes. Black

Contamination of estuaries from failing septic tank systems: difficulties in scaling up from monitored individual systems to cumulative impact.

Science.gov (United States)

Geary, Phillip; Lucas, Steven

2018-02-03

Aquaculture in many coastal estuaries is threatened by diffuse sources of runoff from different land use activities. The poor performance of septic tank systems (STS), as well as runoff from agriculture, may contribute to the movement of contaminants through ground and surface waters to estuaries resulting in oyster contamination, and following their consumption, impacts to human health. In monitoring individual STS in sensitive locations, it is possible to show that nutrients and faecal contaminants are transported through the subsurface in sandy soils off-site with little attenuation. At the catchment scale however, there are always difficulties in discerning direct linkages between failing STS and water contamination due to processes such as effluent dilution, adsorption, precipitation and vegetative uptake. There is often substantial complexity in detecting and tracing effluent pathways from diffuse sources to water bodies in field studies. While source tracking as well as monitoring using tracers may assist in identifying potential pathways from STS to surface waters and estuaries, there are difficulties in scaling up from monitored individual systems to identify their contribution to the cumulative impact which may be apparent at the catchment scale. The processes which may be obvious through monitoring and dominate at the individual scale may be masked and not readily discernible at the catchment scale due to impacts from other land use activities.

Hydrogeological Study of Mangrove Areas Around Guanabara Bay, Rio de Janeiro, Brazil

Directory of Open Access Journals (Sweden)

Gerson Cardoso da Silva Júnior;

2003-01-01

Full Text Available The study area covers part of the mangrove belt located around Guanabara Bay, Rio de Janeiro, Brazil. Representing a continental-marine transition, the mangrove ecosystem is very susceptible to environmental variations and impacts. The vegetation cover plays an important role in prevention of erosion and contamination processes in those areas. An ongoing extensive research effort in the Petrochemical Complex of Duque de Caxias, Rio de Janeiro State, Brazil, focuses on the man-induced changes in the physical environment (soils, groundwater flow system, type and volumes of contaminants, geochemical aspects and the consequences on the neighboring mangrove ecosystem. This article describes the importance of hydrogeological studies in mangrove areas as part of an appropriate environmental assessment, taking as an example an industrial dumping area located in that Petrochemical Complex. Field work included extensive drilling and sampling to obtain basic geological and hydrogeological parameters and data in the pilot area, such as hydraulic conductivity and piezometric heads; emphasizing the tracking of possible contamination by industrial effluents and the marine influence; validation of the conceptual model with mathematical models (numerical and analytical models was carried out. Results show the great importance of well conducted and detailed hydrogeological studies to properly address environmental problems caused by industrial plants in mangrove areas.

Reproduction and structure of the population of the Chaetognath Parasagitta friderici in Guanabara Bay (Brazil based on short term sampling

Directory of Open Access Journals (Sweden)

Fabiana Mendes

2012-03-01

Full Text Available The aim of this study was to describe the total density, densities of developmental stages and the reproduction period of Parasagitta friderici. Weekly samples were collected at one station in the channel of Guanabara Bay, Rio de Janeiro, during one year. Three vertical hauls were made for each sample, and P. friderici was separated, the developmental stages were identified, and body length (BL, ovary length (OL and seminal vesicle width (SVW were measured. Throughout the year P. friderici was the most abundant chaetognath species occurring in all four developmental stages, the densities of which varied from week to week. Higher densities of adults occurred in the spring, followed by peaks of juveniles in the summer. Although P. friderici seems to reproduce continuously in Guanabara Bay, a reproductive peak was apparent during the spring. The intensification of reproduction during the spring, with juveniles occurring in the summer, seems to be related to the period of higher food supply during the rainy season and intrusions of the South Atlantic Central Water.O objetivo deste estudo foi descrever a densidade total, densidades dos estágios de desenvolvimento e o período reprodutivo de Parasagitta friderici. As coletas foram realizadas semanalmente durante um ano em uma estação no canal da Baía de Guanabara, Rio de Janeiro. Foram realizados três arrastos verticais em cada amostragem e, P. friderici foi separada, os estágios de desenvolvimento identificados e o comprimento do corpo, comprimento dos ovários e a largura da vesícula seminal foram medidos. Ao longo do ano, P. friderici foi a espécie de Chaetognatha mais abundante, ocorrendo em todos os quatro estágios de desenvolvimento, dos quais as densidades variaram entre as semanas. As densidades mais altas de adultos ocorreram na primavera seguidas de picos de juvenis no verão. Embora, P. friderici se reproduza continuamente na baía de Guanabara, um pico reprodutivo foi aparente

Linking human impacts within an estuary to ebb-tidal delta evolution

Science.gov (United States)

Dallas, Kate L.; Barnard, Patrick L.

2009-01-01

San Francisco Bay, California, USA is among the most anthropogenically altered estuaries in the entire United States, but the impact on sediment transport to the coastal ocean has not been quantified. Analysis of four historic bathymetric surveys has revealed large changes to the morphology of the San Francisco Bar, an ebb-tidal delta at the mouth of the San Francisco Bay. From 1873 to 2005 the bar eroded an average of 80 cm, which equates to a total volume loss of 100 + 65 x 106 m3 of sediment. Comparison of the surveys indicates the entire ebb delta has contracted radially while its crest has moved landward an average of 1 km. Compilation of historic records reveals that 130 x 106 m3 of sediment has been permanently removed from the San Francisco Bay and adjacent coastal ocean. Constriction of the bar is hypothesized to be from a decrease in sediment supply from San Francisco Bay, a reduction in the tidal prism of the estuary, and/or a reduction in the input of hydraulic mining debris. Changes to the morphology of the San Francisco Bar have likely altered wave refraction and focusing patterns on adjacent beaches and may be a factor in persistent beach erosion occurring in the area.

Managed nutrient reduction impacts on nutrient concentrations, water clarity, primary production, and hypoxia in a north temperate estuary

Science.gov (United States)

Oviatt, Candace; Smith, Leslie; Krumholz, Jason; Coupland, Catherine; Stoffel, Heather; Keller, Aimee; McManus, M. Conor; Reed, Laura

2017-12-01

Except for the Providence River and side embayments like Greenwich Bay, Narragansett Bay can no longer be considered eutrophic. In summer 2012 managed nitrogen treatment in Narragansett Bay achieved a goal of reducing effluent dissolved inorganic nitrogen inputs by over 50%. Narragansett Bay represents a small northeast US estuary that had been heavily loaded with sewage effluent nutrients since the late 1800s. The input reduction was reflected in standing stock nutrients resulting in a statistically significant 60% reduction in concentration. In the Providence River estuary, total nitrogen decreased from 100 μm to about 40 μm, for example. We tested four environmental changes that might be associated with the nitrogen reduction. System apparent production was significantly decreased by 31% and 45% in the upper and mid Bay. Nutrient reductions resulted in statistically improved water clarity in the mid and upper Bay and in a 34% reduction in summer hypoxia. Nitrogen reduction also reduced the winter spring diatom bloom; winter chlorophyll levels after nutrient reduction have been significantly lower than before the reduction. The impact on the Bay will continue to evolve over the next few years and be a natural experiment for other temperate estuaries that will be experiencing nitrogen reduction. To provide perspective we review factors effecting hypoxia in other estuaries with managed nutrient reduction and conclude that, as in Narragansett Bay, physical factors can be as important as nutrients. On a positive note managed nutrient reduction has mitigated further deterioration in most estuaries.

Sea level rise in the Severn Estuary and Bristol Channel and impacts of a Severn Barrage

Science.gov (United States)

Ahmadian, Reza; Olbert, Agnieszka I.; Hartnett, Michael; Falconer, Roger A.

2014-05-01

Many research projects in recent years have focused on marine renewable energy devices and structures due to the growing interest in marine renewable energy. These devices and structures have very different life spans. Schemes such as the Severn Barrage in the UK, as originally proposed by the Severn Tidal Power Group (STPG), would be the largest tidal renewable energy generation project in the world and would be operational for well over a century if built. Due to the long working life of some of these marine renewable energy schemes, it is important to study the impacts of climate change on such schemes, and particularly sea level rise. This study focuses on investigating the impacts of sea level rise due to climate change on the largest macro-tidal estuary in the UK, namely the Severn Estuary and Bristol Channel, and the alterations of the impacts and the performance of the Severn Barrage as a result of climate change. A hierarchy of computer models was implemented to identify the more localised impacts of climate change in the region of the study. Moreover, the potential benefits of the barrage on reducing flood risk, as well as the impact of climate change and the barrage on intertidal mudflats were investigated. The model predictions showed that the barrage would reduce flood risk due to the sea level rise. Furthermore, annual power output and the initial reduction in flood risk of the barrage would not be affected by sea level rise.

Impacts of the Garafiri hydroelectric dam on the Konkoure estuary

International Nuclear Information System (INIS)

Samoura, K.; Waaub, J.P.

2008-01-01

This article described the environmental impacts caused by the exploitation of one or several dams in tropical coastal basins. In particular, it proposed a methodological approach for analyzing the vulnerability of ecosystems to modifications caused by the exploitation of the Garafiri hydroelectric dam in Guinea. With an installed power capacity of 75 MW, this dam has been operational since 1999 and has supplied electricity to coastal and mid Guinea since 2000. Since then, the ecosystem of the Konkoure River has undergone important changes. This study focused primarily on impacts during the dry season. Data was collected at different hydroelectric stations along the Konkoure Basin to estimate changes in water flow in the estuary. The study showed several changes, including noticeable impacts on the soil salt content. In addition, changes in vegetation were attributed to changes in soil content. The study revealed that rice production has increased 65 per cent since 2000, while salt exploitation has been completely discontinued. It was concluded that the hydraulic management of the dam can have a significant impact on the region's ecosystem which can in turn influence ecological and social economic functions. It was concluded that the vulnerability of the ecosystem can be worsened in the context of climate change. 25 refs., 9 figs

Nutrients in estuaries — An overview and the potential impacts of climate change

International Nuclear Information System (INIS)

Statham, Peter J.

2012-01-01

The fate and cycling of macronutrients introduced into estuaries depend upon a range of interlinked processes. Hydrodynamics and morphology in combination with freshwater inflow control the freshwater flushing time, and the timescale for biogeochemical processes to operate that include microbial activity, particle-dissolved phase interactions, and benthic exchanges. In some systems atmospheric inputs and exchanges with coastal waters can also be important. Climate change will affect nutrient inputs and behaviour through modifications to temperature, wind patterns, the hydrological cycle, and sea level rise. Resulting impacts include: 1) inundation of freshwater systems 2) changes in stratification, flushing times and phytoplankton productivity 3) increased coastal storm activity 4) changes in species and ecosystem function. A combination of continuing high inputs of nutrients through human activity and climate change is anticipated to lead to enhanced eutrophication in the future. The most obvious impacts of increasing global temperature will be in sub-arctic systems where permafrost zones will be reduced in combination with enhanced inputs from glacial systems. Improved process understanding in several key areas including cycling of organic N and P, benthic exchanges, resuspension, impact of bio-irrigation, particle interactions, submarine groundwater discharges, and rates and magnitude of bacterially-driven recycling processes, is needed. Development of high frequency in situ nutrient analysis systems will provide data to improve predictive models that need to incorporate a wider variety of key factors, although the complexity of estuarine systems makes such modelling a challenge. However, overall a more holistic approach is needed to effectively understand, predict and manage the impact of macronutrients on estuaries. -- Highlights: ► Estuarine macronutrient behaviour defined by both physical and biogeochemical processes. ► Climate change impacts: sea level

Oceanographic characteristics of an impacted coastal bay: Baía de Guanabara, Rio de Janeiro, Brazil

Science.gov (United States)

Kjerfve, Björn; Ribeiro, Cesar H. A.; Dias, Gilberto T. M.; Filippo, Alessandro M.; Da Silva Quaresma, Valéria

1997-11-01

Baía de Guanabara is a 384 km 2 eutrophic coastal bay in Brazil, impacted by the polluted discharge from the Rio de Janeiro metropolitan area. The structurally controlled bay has a central channel with a depth of 30 m and a sandy bottom near the entrance, reflecting wave and tidal forcing. In contrast, the bay-averaged water depth is 5.7 m and the bottom sediments are mostly muds as a result of the Holocene transgression and rapid fluvial sedimentation, accelerated by channelization of rivers and deforestation. An extensive sand bank is located seaward of the bay entrance and a flood-oriented sand wave system indicates sand transport into the bay. The mean freshwater discharge measures 100±59 m 3 s -1 and is greatest in the rainy austral summer in December and January. Tides are mixed mainly semidiurnal with a range of 0.7 m, and peak spring tidal currents reach 0.5 m s -1 inside the bay and 1.6 m s -1 near the bay entrance. The passage of northward propagating polar fronts results in regular strong southwesterly winds and heavy wave forcing. The bay has mean salinities from 21.0 to 34.5‰ with an average of 29.5±4.8‰. The vertical salinity stratification, Δs/s, varies from 0.06 to 0.21 and is relatively weak and inversely proportional to rms tidal currents. The residual circulation is characterized by both gravitational circulation and transverse residual tidal circulation, measuring 800 and 400 m 3 s -1 respectively. The renewal time of 50% of the bay water volume is 11.4 days. Untreated sewage runoff enters the bay from the west, resulting in locally poor water quality, where the near-bottom mean dissolved oxygen measures only 3.1 mg 1 -1 and results in anoxic bottom muds. The worst water quality is indicated by average fecal coliform of 1140 counts ml -1 and excessive ammonia and phosphate loading. The average chlorophyll concentration in this region responds to the nutrient loading and exceeds 130 μg 1 -1 although 57 μg 1 -1 is the overall mean for

Succession in rocky intertidal benthic communities in areas with different pollution levels at Guanabara Bay (RJ-Brazil)

OpenAIRE

Breves-Ramos, André; Lavrado, Helena Passeri; Junqueira, Andrea de Oliveira Ribeiro; Silva, Sérgio Henrique Gonçalves da

2005-01-01

The aim of this study was to describe and compare the succession of intertidal benthic communities in two areas at Guanabara Bay, RJ, Brazil: Urca, an area submitted to moderated organic pollution and Catalão, an extremely polluted area. Three transects in each area were scraped one month before the beginning of this study in order to evaluate the recruitment (recruitment-treatments). Three other transects were monitored without manipulation (monitoring treatments). Species composition and re...

A novel approach for characterization of polycyclic aromatic hydrocarbon (PAH) pollution patterns in sediments from Guanabara Bay, Rio de Janeiro, Brazil

International Nuclear Information System (INIS)

Christensen, Jan H.; Tomasi, Giorgio; Scofield, Arthur de Lemos; Meniconi, Maria de Fatima Guadalupe

2010-01-01

A novel multivariate method based on principal component analysis of pre-processed sections of chromatograms is used to characterize the complex PAH pollution patterns in sediments from Guanabara Bay, Brazil. Five distinct sources of 3- to 6-ring PAHs could be revealed. The harbour is the most contaminated site in the bay, its plume stretches in a South West to North East direction and the chemical profile indicates mainly pyrogenic sources mixed with a fraction of high-molecular-weight petrogenic PAHs. Rio Sao Joao de Meriti is the second largest source of PAHs, and introduces mainly a fraction of low-molecular-weight petrogenic PAHs from the western region of Rio de Janeiro. The sites close to the ruptured pipeline at the Duque de Caxias Refinery show a distinctive pollution pattern indicating a heavy petroleum fraction. The method also led to the identification of new potential indicator ratios also involving coeluting peaks (e.g., triphenylene and chrysene). - A novel multivariate method is used to characterize the complex PAH pollution patterns in sediments from Guanabara Bay, Brazil.

Tidal exchange between a freshwater tidal marsh and an impacted estuary: the Scheldt estuary, Belgium

NARCIS (Netherlands)

van Damme, S.; Dehairs, F.; Tackx, M.; Beauchard, O.; Struyf, E.; Gribsholt, B.; van Cleemput, O.; Meire, P.

2009-01-01

Tidal marsh exchange studies are relatively simple tools to investigate the interaction between tidal marshes and estuaries. They have mostly been confined to only a few elements and to saltwater or brackish systems. This study presents mass-balance results of an integrated one year campaign in a

Baia de Guanabara pipelines - rehabilitation and integrity management; Reabilitacao e gerenciamento da integridade dos dutos da Baia de Guanabara

Energy Technology Data Exchange (ETDEWEB)

Souza, Ricardo D. de; Matsuura, Minoru [TRANSPETRO - PETROBRAS Transportes, Rio de Janeiro, RJ (Brazil)

2003-07-01

In 2001 PETROBRAS implemented a new Standard for Pipeline Structural Integrity Management of PETROBRAS (PID). All pipelines operated by PETROBRAS had to be adapted to the new requirements imposed by this Standard. When this standard was applied to the Guanabara Bay pipeline many facilities had to be adapted, new inspection procedures implemented and inspection reports reviewed. The first action was to map all pipelines, using a range of techniques, to determine their accurate 3D position. The sections not buried were inspected by divers to identify free spans that exceeded the recommended limits. Launchers were installed in the lines going to the piers to allow in-line inspection. This inspection detected many dents caused by vessels, internal corrosion and external corrosion in the inter-tidal zone. The corrosion monitoring system was redesigned and new monitoring points were installed to provide more accurate information on the high risk areas. The cathodic protection system was adapted to provide remote monitoring and data analysis. A new routine of geotechnical inspections, on-shore inspections and helicopter surveys has been implemented. Defects identified by the in-line inspection have been assessed in a conservative way and all lines have been hydrostatically tested to demonstrate continued fitness for purpose. (author)

Reconstructing historical changes in combustion patterns by means of black carbon and PAH evaluation in dated sediments from Guanabara Bay, Rio de Janeiro

International Nuclear Information System (INIS)

Mauad, Cristiane R.; Wagener, Angela de L. R.; Farias, Cassia de O.; Carreira, Renato S.; Godoy, Jose M.; Scofield, Arthur de L.; Vasconcelos, Crisogono

2013-01-01

The accumulation history of combustion products from the metropolitan area around Guanabara Bay was evaluated using black carbon and polycyclic aromatic hydrocarbons as indicators. BC concentration varied between 0.23 and 0.51%, with an increasing mass accumulation tendency over the last 118 years, whereas a decrease in the values of the ratio BC/organic carbon was observed in the upper sediment layers, probably reflecting the enhancement of bay's eutrophication process in the last 30 years. Higher concentrations of pyrolytic PAH were observed between 1925 and 1976, being consistent with the subsequent deforestation, urbanization, and industrialization that occurred in the Guanabara basin in the period. These PAHs were best characterized by the BFl/(BFl+BePy) diagnostic ratio. The data obtained allowed the characterization of the main events that influenced the combustion patterns in the region: burning of biomass and fossil fuel, economic crisis of 1970 and 1990 and the introduction of ethanol in the Brazilian energetic matrix. (author)

Reconstructing historical changes in combustion patterns by means of black carbon and PAH evaluation in dated sediments from Guanabara Bay, Rio de Janeiro

Energy Technology Data Exchange (ETDEWEB)

Mauad, Cristiane R.; Wagener, Angela de L. R.; Farias, Cassia de O.; Carreira, Renato S.; Godoy, Jose M.; Scofield, Arthur de L., E-mail: angela@puc-rio.b [Pontificia Universidade Catolica do Rio de Janeiro (LABMAM/PUC-Rio), Rio de Janeiro, RJ (Brazil). Departamento de Quimica. Lab. de Estudos Marinhos e Ambientais; Ruiz, Naira M. S.; Menezes, Sonia M.C. de [Centro de Pesquisas e Desenvolvimento Leopoldo A. Miguez de Melo (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil); Vasconcelos, Crisogono [Laboratory of Geomicrobiology, ETH/Zuerich, Zuerich (Switzerland)

2013-11-15

The accumulation history of combustion products from the metropolitan area around Guanabara Bay was evaluated using black carbon and polycyclic aromatic hydrocarbons as indicators. BC concentration varied between 0.23 and 0.51%, with an increasing mass accumulation tendency over the last 118 years, whereas a decrease in the values of the ratio BC/organic carbon was observed in the upper sediment layers, probably reflecting the enhancement of bay's eutrophication process in the last 30 years. Higher concentrations of pyrolytic PAH were observed between 1925 and 1976, being consistent with the subsequent deforestation, urbanization, and industrialization that occurred in the Guanabara basin in the period. These PAHs were best characterized by the BFl/(BFl+BePy) diagnostic ratio. The data obtained allowed the characterization of the main events that influenced the combustion patterns in the region: burning of biomass and fossil fuel, economic crisis of 1970 and 1990 and the introduction of ethanol in the Brazilian energetic matrix. (author)

Cyanobacteria and macroalgae in ecosystem of the Neva estuary

Directory of Open Access Journals (Sweden)

Nikulina V. N.

2011-07-01

Full Text Available The Baltic Sea and Neva estuary are plagued by coastal eutrophication. In order to estimate the scale of the problem, quantitative estimates of phytoplankton and macroalgal mats were determined in the Neva estuary. Long-term monitoring (1982–2009 of phytoplankton showed changes in its species composition and abundance. Summer phytoplankton biomass increased significantly in the 1990s, with concomitant changes in species composition, despite a decline of nutrients in the Neva estuary. The cyanobacteria Planktothrix agardhii became a dominant species. The summer biomass of phytoplankton reached a maximum of 5.2 ± 0.4 mg·L-1 in 2002–2004. Monitoring of macroalgal community in the coastal area of the Neva estuary from 2002 to 2009 showed the dominance of the filamentous green alga Cladophora glomerata in the phytobenthos. Average biomass of macroalgae in inner and outer estuary differed significantly at 132 ± 29 and 310 ± 67 g DW·m-2, respectively. This study showed, that fluctuations in macroalgal biomass reflected human influence on estuary, although it was less sensitive to human impact than the phytoplankton community. Thus qualitative and quantitative characteristics of phytoplankton and macroalgal blooms can indicate anthropogenic influence on the ecosystem, and help to better manage the Neva estuary.

Climate Ready Estuaries Partner Projects Map

Science.gov (United States)

CRE partners with the National Estuary Program to develop climate change projects in coastal U.S. areas, such as bays and harbors; to develop adaptation action plans, identify climate impacts and indicators, and more. This map shows project locations.

Non-flood season neap tides in the Yangtze estuary offshore: Flow mixing processes and its potential impacts on adjacent wetlands

Science.gov (United States)

Wei, Taoyuan; Wang, Zhanghua; Chen, Jing; Li, Maotian

2018-02-01

How flow mixing process influences the wetlands of the Yangtze Estuary is still poorly understood. Hydrological fieldwork was conducted on five vessel-anchored sites (S1-S2; M1-M2-M3) near the major wetlands of the Yangtze Estuary offshore (121°57‧-122°30‧E, 30°50‧-31°23‧N) on May 8-11 2004, to examine the dynamics of neap tides in the non-flood season of the Yangtze (∼24, 700 m3s-1 at Datong) and their impacts on adjacent wetlands. Based on the measurement of the acoustic Doppler current profiler (aDcp), direct-reading current meter and optical backscattering sensor (OBS-3A), two flow patterns were revealed: 1) well mixing flow pattern caused by the turbulent tidal currents, and 2) weak mixing flow pattern resulted by the estuarine circulation in the North Port of the estuary. The characteristics of such different flow patterns were analyzed and resultant sediment dispersals were discussed in relation to the adjacent wetlands. It is suggested that the estuarine circulation might be the important process to nourish the eastern wetland of the Yangtze Estuary which has been neglected before.

Scavenging rate ecoassay: a potential indicator of estuary condition.

Science.gov (United States)

Porter, Augustine G; Scanes, Peter R

2015-01-01

Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress.

Experimental essay and numerical modelling in a reduced model with physical similarity to a pipeline with zig-zag geometry in Guanabara Bay (PE-3); Ensaio experimental e modelagem numerica em modelo reduzido com semelhanca fisica do duto com geometria zig-zag da Baia de Guanabara (PE-3)

Energy Technology Data Exchange (ETDEWEB)

Poiate, Junior, Edgard; Costa, Alvaro M. da; Amaral, Claudio S; Rocha, Renato S [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES); Guimaraes, Giuseppe B; Souza, Pablo F [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)

2003-07-01

In January 2000 PETROBRAS faced a leakage of heavy heated MF380 oil from a 16'' pipeline in Guanabara Bay. The thermal structural buckling of the pipeline, interacting with the soil, induced the rupture of the pipeline wall, causing the leakage of oil. In order to overcome this undesired phenomenon PETROBRAS studied several alternatives of a new pipeline. As a result of these studies a pipeline with 'ZIGZAG' geometry was adopted, named PE-3. Due to the very few applications of this kind of concept by the oil industry and in different soil conditions compared to the existing one in Guanabara Bay, a very sophisticated procedure including the simulation of the thermal mechanical interactions between the soil and the pipeline structure was developed. Computer modeling was carried out using the finite element method considering the soil and pipeline non-linear material behavior and finite displacements. In order to validate the numerical modelling was build an experimental test in a reduced model with physics similarity of a pipeline with ZIG-ZAG geometry (PE-3). The numerical and experimental results are comparing and have a good agreement. (author)

Mangrove clearing impacts on macrofaunal assemblages and benthic food webs in a tropical estuary.

Science.gov (United States)

Bernardino, Angelo Fraga; Gomes, Luiz Eduardo de Oliveira; Hadlich, Heliatrice Louise; Andrades, Ryan; Correa, Lucas Barreto

2018-01-01

Despite over 21,000ha of mangrove forests being removed per year in Brazil, ecological changes following mangrove deforestation have been overlooked. Here we evaluated changes in benthic macrofaunal assemblages and food-webs at a mangrove removal and natural sites in a tropical estuary in Eastern Brazil. The impacted site had coarser sediment particle sizes suggesting significant changes in sedimentation processes after forest clearing. Spatial differences in macrofaunal abundance, biomass and diversity were not directly associated with the removal of mangrove forests, supporting recolonization of impacted areas by estuarine fauna. However, benthic assemblage composition, infaunal δ 13 C signatures and food-web diversity markedly differed at the impacted site being strongly related to sedimentary changes. The loss of infaunal trophic diversity that followed mangrove removal suggests that large-scale forest clearing may impact estuarine food webs, with potential consequences to nearby coastal ecosystems given the high clearing rate of mangrove forests in Brazil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radiological assessment of the Esk Estuary

International Nuclear Information System (INIS)

Howorth, J.M.; Barr, H.M.; Toole, J.; Strange, L.P.

1993-01-01

An assessment has been carried out of the radiological impact of artificial radionuclides in the Esk estuary in Cumbria, UK. Measurements were made of the distributions of 137 Cs, 239 + 240 Pu, and 241 Am in water, surface bed sediments and core profiles. The highest measured concentrations in surface sediments were 2.8 Bq g -1 of 137 Cs, 3.1 Bq g -1 of 239 + 240 Pu and 4.7 Bq g -1 of 241 Am. These values represent significant decreases from similar measurements made in 1970-1980. The measured behaviour of the actinides in low salinity water at the head of the estuary supports previous observations of actinide remobilisation from the bed. A model has been developed which simulates the long-term behaviour of radioactivity in the estuary. The model incorporates representations of tidal mixing, sediment transport, seasonal and long-term sediment accretion. The model also represents long-term build-up in salt marsh regions. The model gives good agreement with measured distributions of 137 Cs, but tends to underestimate actinide concentrations by factors of 2-3. Dose calculations show the importance of radionuclide uptake through livestock grazing sea-washed pasture alongside the estuary. 137 Cs and 241 Am are identified as the most important radionuclides considered in the assessment. (Author)

Geochemistry and mineralogy of recent sediments of Guanabara Bay (NE sector) and its major rivers - Rio de Janeiro State - Brazil

OpenAIRE

FARIA, MARCIA DE MELO; SANCHEZ, BRAZ A.

2001-01-01

Geochemical and clay mineralogical studies of bottom sediments collected along the Macacu and Caceribu rivers and Guanabara Bay were carried out in order to investigate the relationship between major source areas and recent sediments of the bay. Clay mineralogy includes different groups with selective distribution conditioned by geomorphic features and depositional settings. Micaceous clay minerals are abundant near parent rock in the upper course, whereas kaolinite derived from varied source...

Biochemical responses and physiological status in the crab Hemigrapsus crenulatus (Crustacea, Varunidae) from high anthropogenically-impacted estuary (Lenga, south-central Chile).

Science.gov (United States)

Díaz-Jaramillo, M; Socowsky, R; Pardo, L M; Monserrat, J M; Barra, R

2013-02-01

Estuarine environmental assessment by sub-individual responses is important in order to understand contaminant effects and to find suitable estuarine biomonitor species. Our study aimed to analyze oxidative stress responses, including glutathione-S-transferase (GST) activity, total antioxidant capacity (ACAP) and lipid peroxidation levels (TBARS) in estuarine crabs Hemigrapsus crenulatus from a high anthropogenically-impacted estuary (Lenga) compared to low and non-polluted estuaries (Tubul and Raqui), in a seasonal scale (winter-summer), tissue specific (hepatopancreas and gills) and sex related responses. Results showed that hepatopancreas in male crabs better reflected inter-estuary differences. Morpho-condition traits as Cephalothorax hepatopancreas index (CHI) could be used as an indicator of physiological status of estuarine crabs. Discriminant analysis also showed that GST and TBARS levels in summer are more suitable endpoints for establishing differences between polluted and non-polluted sites. These results suggest the importance of seasonality, target tissue, sex and physiological status of brachyuran crabs for estuarine biomonitoring assessment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Potential Climate-Induced Runoff Changes and Associated Uncertainty in Four Pacific Northwest Estuaries

Science.gov (United States)

As part of a larger investigation into potential impacts of climate change on estuarine habitats in the Pacific Northwest (PNW), we estimated changes in freshwater inputs into four estuaries. These were the Coquille River estuary, the South Slough of Coos Bay, and the Yaquina Bay...

Avaliação da Poluição Antrópica Usando Padrão de Distribuição deEspécies de Foraminíferos Provenientes de Testemunhos da Baía de Guanabara, RJ.

Directory of Open Access Journals (Sweden)

Brígida Orioli Figueira

2007-07-01

Full Text Available This work presents a study of benthic foraminifera recovered from three cores collected near the Paquetá island, in the Guanabara bay, Rio de Janeiro, southeastern Brazil. The cores have different sizes and were subsampled in centimetric intervals. The recovered benthic foraminiferal assemblages were thoroughly identified, in order to carry out an ecological study towards reconstructing the environmental evolution of the studied area during the recent historical period and assessing the response of the foraminiferal assemblages to the locally occurring natural and/or anthropogenic impacts. The microfaunal distribution results were correlated with the sedimentological and TOC (Total Organic Carbon data to understand the environmental trends and evaluate the varying patterns of human-related pollution in the area. 14C isotopic date was taken at the bottom of one core, to help for the local sediment accumulation rates. Species diversity values were low in all samples, whereas the TOC values were commonly high, increasing dramatically upwards across the cores.The dominant species in that area of the Guanabara bay were Ammonia tepida, Elphidium spp. and Buliminella elegantissima. Patterns of the distributions of these species confirm the influence of the anthropogenic pollutiontoward the top of the cores.

Impact of entrainment and impingement on fish populations in the Hudson River estuary. Volume I. Entrainment-impact estimates for six fish populations inhabiting the Hudson River estuary

International Nuclear Information System (INIS)

Boreman, J.; Barnthouse, L.W.; Vaughn, D.S.; Goodyear, C.P.; Christensen, S.W.; Kumar, K.D.; Kirk, B.L.; Van Winkle, W.

1982-01-01

This volume is concerned with the estimation of the direct (or annual) entrainment impact of power plants on populations of striped bass, white perch, Alosa spp. (blueback herring and alewife), American shad, Atlantic tomcod, and bay anchovy in the Hudson River estuary. Entrainment impact results from the killing of fish eggs, larvae, and young juveniles that are contained in the cooling water cycled through a power plant. An Empirical Transport Model (ETM) is presented as the means of estimating a conditional entrainment mortality rate (defined as the fraction of a year class which would be killed due to entrainment in the absence of any other source of mortality). Most of this volume is concerned with the estimation of several parameters required by the ETM: physical input parameters (e.g., power-plant withdrawal flow rates); the longitudinal distribution of ichthyoplankton in time and space; the duration of susceptibility of the vulnerable organisms; the W-factors, which express the ratios of densities of organisms in power plant intakes to densities of organisms in the river; and the entrainment mortality factors (f-factors), which express the probability that an organism will be killed if it is entrained. Once these values are obtained, the ETM is used to estimate entrainment impact for both historical and projected conditions

Time-dependence of salinity in monsoonal estuaries

Digital Repository Service at National Institute of Oceanography (India)

Vijith, V.; Sundar, D.; Shetye, S.R.

processes (diffusion, gravity current formation, impact of tidal asymmetries, etc.) is balanced by salinity-egress induced by runoff. Here we point out that the salinity field of the estuaries that are located on the coasts of the Indian subcontinent...

Estuary-wide genetic stock distribution and salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

Introgression between ecologically distinct species following increased salinity in the Colorado Delta- Worldwide implications for impacted estuary diversity.

Science.gov (United States)

Lau, Clive L F; Jacobs, David K

2017-01-01

We investigate hybridization and introgression between ecologically distinct sister species of silverside fish in the Gulf of California through combined analysis of morphological, sequence, and genotypic data. Water diversions in the past century turned the Colorado River Delta from a normal estuary to a hypersaline inverse estuary, raising concerns for the local fauna, much of which is endangered. Salinity differences are known to generate ecological species pairs and we anticipated that loss of the fresher-water historic salinity regime could alter the adaptive factors maintaining distinction between the broadly distributed Gulf-endemic Colpichthys regis and the narrowly restricted Delta-endemic Colpichthys hubbsi , the species that experienced dramatic environmental change. In this altered environmental context, these long-isolated species (as revealed by Cytochrome b sequences) show genotypic (RAG1, microsatellites) evidence of active hybridization where the species ranges abut, as well as directional introgression from C. regis into the range center of C. hubbsi . Bayesian group assignment (STRUCTURE) on six microsatellite loci and multivariate analyses (DAPC) on both microsatellites and phenotypic data further support substantial recent admixture between the sister species. Although we find no evidence for recent population decline in C. hubbsi based on mitochondrial sequence, introgression may be placing an ancient ecological species at risk of extinction. Such introgressive extinction risk should also pertain to other ecological species historically sustained by the now changing Delta environment. More broadly, salinity gradient associated ecological speciation is evident in silverside species pairs in many estuarine systems around the world. Ecological species pairs among other taxa in such systems are likely poorly understood or cryptic. As water extraction accelerates in river systems worldwide, salinity gradients will necessarily be altered, impacting

Introgression between ecologically distinct species following increased salinity in the Colorado Delta- Worldwide implications for impacted estuary diversity

Directory of Open Access Journals (Sweden)

Clive L.F. Lau

2017-12-01

altered, impacting many more estuary and delta systems. Such alteration of habitats will place biodiversity at risk not only from direct effects of habitat destruction, but also from the potential for the breakdown of ecological species. Thus, evolutionary response to the anthropogenic alteration of salinity gradients in estuaries merits investigation as the number of impacted systems increases around the globe, permitting parallel study of multiple systems, while also permitting a conservation management response to help preserve this little championed component of biodiversity.

Application of remote sensing data for oil spill monitoring in the Guanabara bay, Rio de Janeiro, Brazil

Energy Technology Data Exchange (ETDEWEB)

Bentz, Cristina Maria; Miranda, Fernando Pellon de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Centro de Excelencia em Geoquimica

2001-07-01

This paper describes the application of remote sensing data for oil spill monitoring in the Guanabara Bay, Rio de Janeiro, Brazil. During the emergency, Landsat-5/T M (Thematic Mapper) and Radar sat-1 data were acquired to monitor the location of the spill and its movement. Image classification procedures have been utilized to highlight oil-covered areas on the water surface. Ambiguities in the oil detection were resolved with the aid of ancillary information in a GIS (Geographic Information System) environment. The results obtained helped PETROBRAS to optimize the emergency response procedures and subsequent cleaning efforts. (author)

From headwaters to coast: Influence of human activities on water quality of the Potomac River Estuary

Science.gov (United States)

Bricker, Suzanne B.; Rice, Karen C.; Bricker, Owen P.

2014-01-01

The natural aging process of Chesapeake Bay and its tributary estuaries has been accelerated by human activities around the shoreline and within the watershed, increasing sediment and nutrient loads delivered to the bay. Riverine nutrients cause algal growth in the bay leading to reductions in light penetration with consequent declines in sea grass growth, smothering of bottom-dwelling organisms, and decreases in bottom-water dissolved oxygen as algal blooms decay. Historically, bay waters were filtered by oysters, but declines in oyster populations from overfishing and disease have led to higher concentrations of fine-sediment particles and phytoplankton in the water column. Assessments of water and biological resource quality in Chesapeake Bay and tributaries, such as the Potomac River, show a continual degraded state. In this paper, we pay tribute to Owen Bricker’s comprehensive, holistic scientific perspective using an approach that examines the connection between watershed and estuary. We evaluated nitrogen inputs from Potomac River headwaters, nutrient-related conditions within the estuary, and considered the use of shellfish aquaculture as an in-the-water nutrient management measure. Data from headwaters, nontidal, and estuarine portions of the Potomac River watershed and estuary were analyzed to examine the contribution from different parts of the watershed to total nitrogen loads to the estuary. An eutrophication model was applied to these data to evaluate eutrophication status and changes since the early 1990s and for comparison to regional and national conditions. A farm-scale aquaculture model was applied and results scaled to the estuary to determine the potential for shellfish (oyster) aquaculture to mediate eutrophication impacts. Results showed that (1) the contribution to nitrogen loads from headwater streams is small (about 2 %) of total inputs to the Potomac River Estuary; (2) eutrophic conditions in the Potomac River Estuary have improved in

75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

Science.gov (United States)

2010-06-21

... Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration Strategy; Request... interagency Estuary Habitat Restoration Council, is providing notice of the Council's intent to revise the ''Estuary Habitat Restoration Strategy'' and requesting public comments to guide its revision. DATES...

Trace/heavy metal pollution monitoring in estuary and coastal area of Bay of Bengal, Bangladesh and implicated impacts.

Science.gov (United States)

Kibria, Golam; Hossain, Md Maruf; Mallick, Debbrota; Lau, T C; Wu, Rudolf

2016-04-15

Using artificial mussels (AMs), this study reports and compares time-integrated level of eleven trace metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, U, Zn) in Karnafuli River estuary and coastal area of the Bay of Bengal, Bangladesh. Through this study, "hot spots" of metal pollution were identified. The results may demonstrate that the Karnafuli Estuary, and adjacent coastal area of Chittagong, Bangladesh are highly polluted by high risk metals (cadmium, chromium, copper, mercury, nickel, lead, uranium). Agricultural, domestic and industrial wastes directly discharged into the waterways have been identified as the main causes of metal pollution in Chittagong, Bangladesh. The high level of metal pollution identified may impact on local water quality, and seafood catch, livelihoods of people and public health resulting from seafood consumption. There is a need for regular monitoring to ascertain that local water quality with respect to metal levels are within acceptable levels to safeguards both environmental health and public health. Copyright © 2016 Elsevier Ltd. All rights reserved.

In-stream PIT detection, estuary wetlands - Columbia River Estuary Tidal Habitats

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

Salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

Impact of freshwater influx on microzooplankton mediated food web in a tropical estuary (Cochin backwaters - India)

Digital Repository Service at National Institute of Oceanography (India)

Jyothibabu, R; Madhu, N.V.; Jayalakshmi, K.V.; Balachandran, K.K.; Shiyas, C.C.; Martin, G.D.; Nair, K.K.C.

-1 Impact of fresh water influx on microzooplankton mediated food web in a tropical estuary (Cochin backwaters - India) R. Jyothibabu A, B, N.V. Madhu A, K.V. Jayalakshmi A, K. K. Balachandran A, C. A. Shiyas A, G. D. Martin A and K. K. C. Nair A A... in the northeastern Atlantic Ocean. Deep Sea Research 40, 479 ? 493. Burkill, P. H., Leaky, R. J. G., Owens, N. J. P., and Mantoura, R. F. C., 1993b. Synechococcus and its importance to the microbial food web of the northwestern Indian Ocean, In: Biogeochemical...

76 FR 70480 - Otay River Estuary Restoration Project, South San Diego Bay Unit of the San Diego Bay National...

Science.gov (United States)

2011-11-14

... River Estuary Restoration Project, South San Diego Bay Unit of the San Diego Bay National Wildlife...), intend to prepare an environmental impact statement (EIS) for the proposed Otay River Estuary Restoration... any one of the following methods. Email: [email protected] . Please include ``Otay Estuary NOI'' in the...

Spatial distribution of iron, copper and lead in mangrove sediments in a degradation gradient in Guanabara Bay (Rio de Janeiro State)

OpenAIRE

Borges, Anderson C.; Dias, Jailson C.; Machado, Wilson; Patchineelam, Sambasiva R.; Sella, Silvia M.

2007-01-01

Iron, copper and lead distribution was evaluated in sediment cores from a disturbed mangrove area in Guanabara Bay: a core from a seaward site where mangrove vegetation was removed ~20 yr before sampling (MD); a core from an intermediate site with dead vegetation, apparently due to insect attack (MP), and a core from a landward site with living vegetation (MV). Metal concentrations showed increasing values seaward while organic matter content showed an inverse trend, displaying a negative cor...

78 FR 1246 - Otay River Estuary Restoration Project; South San Diego Bay Unit and Sweetwater Marsh Unit of the...

Science.gov (United States)

2013-01-08

...-FF08RSDC00] Otay River Estuary Restoration Project; South San Diego Bay Unit and Sweetwater Marsh Unit of the... scoping with regard to the environmental impact statement (EIS) for the proposed Otay River Estuary... one of the following methods. Email: [email protected] . Please include ``Otay Estuary NOI'' in the...

Superficial distribution of aromatic compounds and geomicrobiology of sediments from Suruí Mangrove, Guanabara Bay, RJ, Brazil.

Science.gov (United States)

Fontana, Luiz F; da Silva, Frederico S; de Figueiredo, Natália G; Brum, Daniel M; Netto, Annibal D Pereira; de Gigueiredo Junior, Alberto G; Crapez, Mirian A C

2010-12-01

The distribution of selected aromatic compounds and microbiology were assessed in superficial sediments from Suruí Mangrove, Guanabara Bay. Samples were collected at 23 stations, and particle size, organic matter, aromatic compounds, microbiology activity, biopolymers, and topography were determined. The concentration of aromatic compounds was distributed in patches over the entire mangrove, and their highest total concentration was determinated in the mangrove's central area. Particle size differed from most mangroves in that Suruí Mangrove has chernies on the edges and in front of the mangrove, and sand across the whole surface, which hampers the relationship between particle size and hydrocarbons. An average @ 10% p/p of organic matter was obtained, and biopolymers presented high concentrations, especially in the central and back areas of the mangrove. The biopolymers were distributed in high concentrations. The presence of fine sediments is an important factor in hydrocarbon accumulation. With high concentration of organic matter and biopolymers, and the topography with chernies and roots protecting the mangrove, calmer areas are created with the deposition of material transported by wave action. Compared to global distributions, concentrations of aromatic compounds in Suruí Mangrove may be classified from moderate to high, showing that the studied area is highly impacted.

Nematodes as indicators of shrimp farm impact on an amazonian estuary (Curuçá, Pará, Brazil

Directory of Open Access Journals (Sweden)

Virag Venekey

2016-03-01

Full Text Available Abstract Shrimp farming reduces demand on wild fishery stocks and avoids environmental damage resulting from fishing practices, however, it has the potential to affect the water quality if not properly managed. In this study the impacts of a shrimp farm in an Amazonian estuary were evaluated, focusing on changes in nematodes regarding taxonomic composition, richness, density and diversity. Sampling was conducted in August 2004 (dry season and January 2005 (rainy season in the river at stations situated upstream and downstream at different distances from the main source of farm effluent discharge. Thirty-eight genera were recorded with Terschellingia dominating in the dry season and Terschellingia, Daptonema, Ptycholaimellus and Gomphionema in the rainy season. Abundances were within the range recorded in other estuaries and together with genera richness and diversity showed a strong temporal pattern with significantly higher values in the rainy season. No clear patterns of changes were observed at the stations. Some signs of organic enrichment were detected but they were not yet intense, probably a consequence of the strong local hydrodynamics and the age of the shrimp farm, which was just starting its operation. We recommend that in future studies on farming impacts a combination of factors, beyond the physical and chemical parameters of the water and sediments or taxonomic refinement, should be taken into account - such as the duration of the operation of the farm, the area occupied by ponds and the farm's production. Furthermore, we also believe that nematodes are a useful tool for evaluating aquaculture impacts due to the ease of sampling and because they are organisms at the base of marine food chain.

Drivers of sulfide intrusion in Zostera muelleri in a moderately affected estuary in south-eastern Australia

DEFF Research Database (Denmark)

Holmer, Marianne; Bennett, William W.; Ferguson, Angus J. P.

2017-01-01

The seagrass Zostera muelleri Irmisch ex Asch. is abundant in estuaries in Australia and is under pressure from coastal developments. We studied sulfide intrusion in Z. muelleri along a gradient of anthropogenic impact at five stations in the Wallis Lake estuary, Australia. Results showed differe...

Metabarcoding of benthic eukaryote communities predicts the ecological condition of estuaries

International Nuclear Information System (INIS)

Chariton, Anthony A.; Stephenson, Sarah; Morgan, Matthew J.; Steven, Andrew D.L.; Colloff, Matthew J.; Court, Leon N.; Hardy, Christopher M.

2015-01-01

DNA-derived measurements of biological composition have the potential to produce data covering all of life, and provide a tantalizing proposition for researchers and managers. We used metabarcoding to compare benthic eukaryote composition from five estuaries of varying condition. In contrast to traditional studies, we found biotic richness was greatest in the most disturbed estuary, with this being due to the large volume of extraneous material (i.e. run-off from aquaculture, agriculture and other catchment activities) being deposited in the system. In addition, we found strong correlations between composition and a number of environmental variables, including nutrients, pH and turbidity. A wide range of taxa responded to these environmental gradients, providing new insights into their sensitivities to natural and anthropogenic stressors. Metabarcoding has the capacity to bolster current monitoring techniques, enabling the decisions regarding ecological condition to be based on a more holistic view of biodiversity. - Highlights: • We used metabarcoding to examine the benthic eukaryote composition of five estuaries. • Biotic richness (based on MOTUs) was greater in the most impacted estuary. • Similarities among estuaries reflected their environmental condition. • Composition was strongly correlated with nutrients, turbidity and pH. • Metabarcoding can provide fast, comprehensive and ecologically informative data. - Using metabarcoding we were able discriminate benthos from five estuaries, and identify those taxa which responded negatively and positivity to the key environmental stressors

Estuary Data Mapper (EDM)

Science.gov (United States)

Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

The effects of artificial sandbar breaching on the macrophyte communities of an intermittently open estuary

Science.gov (United States)

Ribeiro, Jose Pedro N.; Saggio, Ângelo; Lima, Maria Inês Salgueiro

2013-04-01

Artificial sandbar opening of intermittently open estuaries is a practice utilised worldwide to improve water quality, fishing, and recreational amenities and to prevent the flooding of adjacent properties. Breaching causes the water level to drop drastically, exposing plants to two water level extremes. With some exceptions, estuarine communities are adversely affected by this practice. Although breaching can happen naturally, artificial breaching is on the rise, and the impact of manipulating water levels on estuarine communities needs to be investigated. In this work, we described the breaching cycles of the Massaguaçu River Estuary and proposed flooding scenarios for the estuary's macrophyte banks based on our data. We calculated the relationship between plant distribution and flooding conditions and used our calculations to predict the estuary community's composition depending on the water level at breaching time. We discovered a strong relationship between plant distribution and flooding conditions, and we predicted that the estuarine community would be markedly different between flooding scenarios. Low frequency flooding scenarios would be related to submerged macrophytes and, as the flooding frequency increases, macrophytes would be replaced by amphibious plants, and eventually by the arboreal stratus. Therefore, we concluded that an increase in artificial breaching cycles would have a detrimental impact on the estuary community.

Origin and composition of particulate organic matter in a macrotidal turbid estuary: The Gironde Estuary, France

Science.gov (United States)

Savoye, Nicolas; David, Valérie; Morisseau, François; Etcheber, Henri; Abril, Gwenaël; Billy, Isabelle; Charlier, Karine; Oggian, Georges; Derriennic, Hervé; Sautour, Benoît

2012-08-01

At the interface between continent and ocean, estuaries receive particles, and especially particulate organic matter (POM) originating from these two reservoirs, but also produce POM, through autochthonous primary production. The origin and composition of surface POM in the Gironde Estuary (SW France) and the environmental forcing of its variability was investigated using the data set produced by the French Coastal Monitoring Network SOMLIT (Service d'Observation en Milieu LITtoral; monthly like sampling during years 2007-2009). This estuary is considered as a model of macrotidal turbid estuaries. Using elemental and isotopic composition of the POM, we estimated that, at the inner estuary space scale and inter-annual time scale, surface particulate organic carbon (POC) was composed of terrestrial POM originated from the turbidity maximum (96.4%; refractory POC) and flood events (1.6%; labile and refractory POC), and of riverine (0.1%), estuarine (0.8%) and marine (1.1%) phytoplankton, i.e. that POC was 98% and 2% of terrestrial and phytoplankton origin, respectively. However, there was a clear spatial gradient: the phytoplankton contribution increases from ca. 1% in the upper and middle estuary to 8.5% in the lower estuary, where light condition is more favourable to plankton growth. The low contribution of phytoplankton to the POC is a characteristic of the Gironde estuary and contrast with other large temperate estuaries. Statistical analysis indicates that salinity, river flow and SPM concentration, and thus associated hydro-dynamic and sedimentary processes, were the only environmental forcings to the composition of surface POC in this system, at intra- and inter-annual time scale. In contrast, temperature and nutrient concentrations, and thus associated processes, do not force this composition of POC. By combining POC fluxes entering the inner estuary (literature data), POC loss as dissolved organic carbon and CO2 and as sediment trapping within the inner

EVALUATION OF THE CONTAMINATION FROM GUANABARA BAY MANGROVES USING CRABS UCIDES CORDATUS AS INDICATORS OF OIL POLLUTANTS AND DEVELOPMENT OF ANALYSIS

OpenAIRE

ADRIANA HADDAD NUDI

2005-01-01

O principal objetivo deste estudo foi validar o caranguejo da espécie Ucides cordatus como organismo indicador de poluição por óleo em áreas de manguezais da Baía de Guanabara. Para isto foram realizadas as seguintes etapas: (1) análises químicas de hidrocarbonetos policíclicos aromáticos (HPAs) em amostras de hepatopâncreas e sedimento por cromatografia gasosa acoplada ao espectrômetro de massas (CG/EM); (2) bioensaios com experimentos de exp...

Does boat traffic cause displacement of fish in estuaries?

Science.gov (United States)

Becker, Alistair; Whitfield, Alan K; Cowley, Paul D; Järnegren, Johanna; Næsje, Tor F

2013-10-15

Estuaries are increasingly under threat from a variety of human impacts. Recreational and commercial boat traffic in urban areas may represent a significant disturbance to fish populations and have particularly adverse effects in spatially restricted systems such as estuaries. We examined the effects of passing boats on the abundance of different sized fish within the main navigation channel of an estuary using high resolution sonar (DIDSON). Both the smallest (100-300 mm) and largest (>501 mm) size classes had no change in their abundance following the passage of boats. However, a decrease in abundance of mid-sized fish (301-500 mm) occurred following the passage of boats. This displacement may be attributed to a number of factors including noise, bubbles and the rapidly approaching object of the boat itself. In highly urbanised estuarine systems, regular displacement by boat traffic has the potential to have major negative population level effects on fish assemblages. Copyright © 2013 Elsevier Ltd. All rights reserved.

Urban microbial ecology of a freshwater estuary of Lake Michigan.

Science.gov (United States)

Fisher, Jenny C; Newton, Ryan J; Dila, Deborah K; McLellan, Sandra L

Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an "urban microbial signature," and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas , and Pseudomonas , which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is likely to occur with potential

Urban microbial ecology of a freshwater estuary of Lake Michigan

Directory of Open Access Journals (Sweden)

Jenny C. Fisher

2015-07-01

Full Text Available Abstract Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an “urban microbial signature,” and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is

Urban microbial ecology of a freshwater estuary of Lake Michigan

Science.gov (United States)

Fisher, Jenny C.; Newton, Ryan J.; Dila, Deborah K.

2015-01-01

Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an “urban microbial signature,” and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is likely to occur with

Large wood in the Snowy River estuary, Australia

Science.gov (United States)

Hinwood, Jon B.; McLean, Errol J.

2017-02-01

In this paper we report on 8 years of data collection and interpretation of large wood in the Snowy River estuary in southeastern Australia, providing quantitative data on the amount, sources, transport, decay, and geomorphic actions. No prior census data for an estuary is known to the authors despite their environmental and economic importance and the significant differences between a fluvial channel and an estuarine channel. Southeastern Australian estuaries contain a significant quantity of large wood that is derived from many sources, including river flood flows, local bank erosion, and anthropogenic sources. Wind and tide are shown to be as important as river flow in transporting and stranding large wood. Tidal action facilitates trapping of large wood on intertidal bars and shoals; but channels are wider and generally deeper, so log jams are less likely than in rivers. Estuarine large wood contributes to localised scour and accretion and hence to the modification of estuarine habitat, but in the study area it did not have large-scale impacts on the hydraulic gradients nor the geomorphology.

Estimating the chlorophyll content in the waters of Guanabara Bay from the LANDSAT multispectral scanning digital data

Science.gov (United States)

Dejesusparada, N. (Principal Investigator); Bentancurt, J. J. V.; Herz, B. R.; Molion, L. B.

1980-01-01

Detection of water quality in Guanabara Bay using multispectral scanning digital data taken from LANDSAT satellites was examined. To test these processes, an empirical (statistical) approach was choosen to observe the degree of relationship between LANDSAT data and the in situ data taken simultaneously. The linear and nonlinear regression analyses were taken from among those developed by INPE in 1978. Results indicate that the major regression was in the number six MSS band, atmospheric effects, which indicated a correction coefficient of 0.99 and an average error of 6.59 micrograms liter. This error was similar to that obtained in the laboratory. The chlorophyll content was between 0 and 100 micrograms/liter, as taken from the MSS of LANDSAT.

Paleoenvironment interpretation of a 1760 years B.P. old sediment in a mangrove area of the Bay of Guanabara, using pollen analysis

OpenAIRE

Barth, Ortrud M.; São-Thiago, Luiz E.U.; Barros, Marcia A.

2006-01-01

A sediment sample was obtained at 122 cm from the top of a drilling core in the Guapimirim mangrove, Bay of Guanabara, and analyzed using pollen analysis. This muddy core reached a sandy ground at 133 cm. 14C datation got the age of 1760 ± 50 years B.P. The most frequent pollen grains were mangrove species of Rhizophora mangle, Laguncularia racemosa and Avicennia schaueriana. "Restinga" and tropical rain forest vegetation was recognized behind the mangrove. After the last sea transgression at...

Water Quality and Environmental Flow Management in Rapidly Urbanizing Shenzhen Estuary Area, China

Science.gov (United States)

Qin, H.; Su, Q.

2011-12-01

Shenzhen estuary is located in a rapidly urbanizing coastal region of Southeast China, and forms the administrative border between mainland China and Hong Kong. It receives the waters of the Shenzhen River, where it enters the Deep Bay. The estuary has great ecological importance with the internationally recognized mangrove wetlands, which provides a habitat for some rare and endangered waterfowl and migratory birds.Water quality in the esturay has deteriorated not only due to increasing wastewater discharges from domestic and industrial sources, but also as a consequence of decreasing base environmental flow during rapid urbanization in the Shenzhen River catchment since 1980s. Measures to improve water quality of the estuary include not only reducing pollutant inputs by intercepting wastewater, but also increasing environmental flow by reusing reclaimed wastewater or withdrawing nearshore seawater into the river. However, salinity alternation due to flow increase is deemed to have impacts on the mangrove wetland ecosystem. In this paper, Environmental Fluid Dynamics Code (EFDC) is used to simulate hydrodynamics, salinity, and water quality condition in the Shenzhen estuary. After calibration and validation, the model is used to evaluate effects of various control measures on water quality improvement and salinity alteration in the estuary. The results indicate that implementing different measures independently does not reach the goals of water quality improvement; furthermore, increasing environmental flow by importing nearshore seawater may greatly increase the salinity in the Shenzhen River, destroy the fresh ecosystem of the river and have non-negligible impacts on the mangrove wetland ecosystem. Based on the effectiveness and impacts of the measures, an integrated measure, which combine pollutant loads reduction and environmental flow increase by reusing reclaimed wastewater, is proposed to achieve water environmental sustainability in the study area.

Optical Changes in a Eutrophic Estuary During Reduced Nutrient Loadings

DEFF Research Database (Denmark)

Pedersen, Troels Møller; Sand-Jensen, Kaj; Markager, Stiig

2014-01-01

Loss of water clarity is one of the consequences of coastal eutrophication. Efforts have therefore been made to reduce external nutrient loadings of coastal waters. This paper documents improvements to water clarity between 1985 and 2008–2009 at four stations in the microtidal estuary Roskilde...... to 74 % in 1985 to 78 to 85 % in 2008–2009. Overall, efforts to reduce nutrient loading and improve water clarity appeared to have had a larger impact on POM* than on Chl a and colored dissolved organic matter concentrations in the estuary, which can account for the decrease in the scatter...

Three dimensional model evaluation of physical alterations of the Caloosahatchee River and Estuary: Impact on salt transport

Science.gov (United States)

Sun, Detong; Wan, Yongshan; Qiu, Chelsea

2016-05-01

Numerical hydrodynamic modeling provides quantitative understanding of how physical alterations of an estuary may alter the waterbody hydrodynamics and the rate of mixing with the ocean. In this study, a three dimensional hydrodynamic model (CH3D) was used to compare simulated salinities between the existing condition and five historical cases representing varying physical alterations of the Caloosahatchee Estuary involving (1) removal of the headwater structure (S-79); (2) removal of the downstream causeway to Sanibel Island; (3) backfilling an oyster bar near the estuary month; (4) refilling the navigation channel; and (5) the pre-development bathymetric condition. The results suggested that some alterations including the Sanibel Causeway, backfilling the oyster bar and the S-79 structure may have some local effects but did not change estuarine salinity structure significantly. Refilling the navigation channel had a more profound effect, resulting in a dry season salinity reduction of about 5 when compared with the existing condition. The reduced salt transport was more pronounced with the pre-development bathymetry because the estuary as a whole was much shallower than today. The significant system-wide increase in salt transport caused by the historic dredging of the navigation channel in the Caloosahatchee Estuary has significant implications in the development of attainable environmental flow targets for protecting the estuarine ecosystem.

Floresta, política e trabalho: a exploração das madeiras-de-lei no Recôncavo da Guanabara (1760-1820 Forest, politics and labor: the extraction of timber in the Recôncavo da Guanabara (1760-1820

Directory of Open Access Journals (Sweden)

Diogo de Carvalho Cabral

2008-06-01

Full Text Available O artigo procura contribuir para o adensamento da historiografia acerca das operações de extração das madeiras-de-lei, espécies de árvores particularmente propícias à construção naval e por isso legalmente reservadas à apropriação preferencial por parte da Coroa portuguesa no território colonial. O recorte espaço-temporal abarca os sertões do Recôncavo da Guanabara (Capitania do Rio de Janeiro e, em particular, a bacia do rio Macacu no final do período colonial. Usa-se documentação variada (crônicas oficiais, descrições de viajantes, correspondência, lista nominativa de habitantes e inventário post-mortem com o objetivo de mostrar que as relações socioeconômicas dos atores envolvidos (funcionários reais, proprietários fundiários, fabricantes, serradores etc. entre si e com a floresta eram ditadas por negociações cotidianas que viabilizavam a 'letra fria' das leis metropolitanas.The article aims to contribute for the still rarified historiography about the extraction of madeiras-de-lei, those tree species that are particularly suitable for shipbuilding and, for that reason, legally reserved for preferential appropriation by the Portuguese crown in the Brazilian colonial territory. The space-temporal outline embraces the inner lands of Recôncavo da Guanabara (Rio de Janeiro captaincy, in particular the Macacu river basin, at the end of the colonial period. Varied documentation (official chronicles, travelers accounts, letters, a economic-demographic census, and a post-mortem inventory is used in order to show that socioeconomic relations among the actors involved (royal bureaucracy, landowners, timber producers, sawyers, etc., and those between them and the forest were dictated by daily life negotiations which made the 'cold letter' of metropolitan laws viable.

Indian estuaries: Dynamics, ecosystems, and threats

Digital Repository Service at National Institute of Oceanography (India)

Shetye, S.R.

the tide pulls the mixed water out of the estuary through its mouth. Different processes within an estuary contribute to mixing of the two waters, the important among these in the Mandovi estuary are: influence of the tide on the advective field within...

Reverse Estuarine Circulation Due to Local and Remote Wind Forcing, Enhanced by the Presence of Along-Coast Estuaries

Science.gov (United States)

Giddings, S. N.; MacCready, P.

2017-12-01

Estuarine exchange flow governs the interaction between oceans and estuaries and thus plays a large role in their biogeochemical processes. This study investigates the variability in estuarine exchange flow due to offshore oceanic conditions including upwelling/downwelling, and the presence of a river plume offshore (from a neighboring estuary). We address these processes via numerical simulations at the mouth of the Salish Sea, a large estuarine system in the Northeast Pacific. An analysis of the Total Exchange Flow indicates that during the upwelling season, the exchange flow is fairly consistent in magnitude and oriented in a positive (into the estuary at depth and out at the surface) direction. However, during periods of downwelling favorable winds, the exchange flow shows significantly more variability including multiple reversals, consistent with observations, and surface intrusions of the Columbia River plume which originates 250 km to the south. Numerical along-strait momentum budgets show that the exchange flow is forced dominantly by the pressure gradients, particularly the baroclinic. The pressure gradient is modified by Coriolis and sometimes advection, highlighting the importance of geostrophy and local adjustments. In experiments conducted without the offshore river plume, reversals still occur but are weaker, and the baroclinic pressure gradient plays a reduced role. These results suggest that estuaries along strong upwelling coastlines should experience significant modulation in the exchange flow during upwelling versus downwelling conditions. Additionally, they highlight the importance of nearby estuaries impacting one-another, not only in terms of connectivity, but also altering the exchange flow.Plain Language SummaryEstuarine systems provide extensive biological and ecological functions as well as contribute to human uses and economies. However, estuaries are susceptible to change and most estuaries have been significantly impacted, threatening

Fisheries and conflicts in Guanabara Bay, Rio de Janeiro, Brazil

Directory of Open Access Journals (Sweden)

Silvio Jablonski

2006-01-01

Full Text Available Despite the magnitude of domestic and industrial pollution, fishery yield registered in several landing points at Guanabara Bay, between April 2001 and March 2002 was slightly over 19,000 tons, corresponding to a value of US$ 4.8 million. When considered only the fish directed to the food market, the total catch amounted to about 6,300 tons and a value of US$ 3.7 million. Only a few fish species reached expressive densities compatible with commercial fisheries. Among small pelagic fish, Atlantic anchoveta and Brazilian sardinella were the dominant species, while in terms of demersal fish, croakers, mullets and catfishes comprised the main part of the catch. The absence of landing data previous to the spilling of 1.3 million liters of oil in January 2000 led to claims by fishermen representative organizations of values corresponding to about 50 years of fish harvest in the bay. Possibly, a data collection network could be established in a participative way with the main fishermen local associations. The relatively stabilized fisheries in the bay suggested that reasonable inferences could be made, without, necessarily having a complete coverage of all landing points.A despeito da magnitude da poluição de origem doméstica e industrial, a produção de pescado registrado em diferentes pontos de desembarque na Baía de Guanabara, entre abril de 2001 e março de 2002, foi ligeiramente superior a 19.000 t, correspondendo em valor a US$ 4.8 milhões. Quando se considera apenas o pescado direcionado para o mercado fresco, a captura total alcançou cerca de 6.300 t e um valor de US$ 3,7 milhões. Somente algumas poucas espécies alcançam densidades expressivas compatíveis com as pescarias comerciais. Entre os pequenos pelágicos, a sardinha boca-torta e a sardinha verdadeira são as espécies dominantes, enquanto para as demersais, a corvina, a tainha e os bagres perfazem a maior parte das capturas. As pescarias para o caranguejo, nos manguezais, e a

Dune Mining and the Nhlabane Estuary, South Africa: the Effect of a Dredger Crossing on the Zoobenthic Community

International Nuclear Information System (INIS)

Vivier, L.; Cyrus, D.P.

1999-01-01

The Nhlabane Estuary, located on the north-east coast of South Africa, is situated in a titanium dune mining lease area. During 1993, a mining dredger and concentrator crossed the middle reaches of the estuary. For this purpose, two berm walls were constructed across the estuary. Two impacts stemmed from the crossing. A series of fine sediment intrusions into the estuary from the berm wall area occurred during late 1993 and early 1994 and caused a rapid decline in benthic densities and number of taxa. Recovery of the affected area was slow and characterized by initial proliferation of opportunistic colonizers. The berm walls, which divided the estuary in half, were kept in place for nearly three years and caused changes in water quality and the benthic community of the upper and lower halves of the estuary. Artificial breaching of the estuary in August 1995 and removal of the berm walls in May 1996 initiated recovery of the estuary. The success of a second dredger crossing, scheduled for January 1999, depends on addressing the mistakes made during the first crossing and on the speed with which the carefully planned crossing operation, berm wall removal and estuary rehabilitation proceed

A synthesis on the assessment of an alternative disposal strategy to serve sustainability in the Scheldt estuary

OpenAIRE

Roose, F.; Plancke, Y.; Ides, S.

2008-01-01

The Scheldt estuary is characterised by a valuable multiple-channel system consisting of sandbars in between primary and secondary channels. Within the framework of the Long Term Vision (LTV) for the Scheldt estuary the conservation of this multiple-channel system is defined as the key goal to achieve morphological sustainability.Dredging is one of the human activities having an impact on morphology, hence dredging and disposal should be optimised by minimising the negative impact on morpholo...

Carbon dioxide emissions from Indian monsoonal estuaries

Science.gov (United States)

Sarma Vedula, VSS

2012-07-01

The oceans act as a net sink for atmospheric CO2, however, the role of coastal bodies on global CO2 fluxes remains unclear due to lack of data. The estimated absorption of CO2 from the continental shelves, with limited data, is 0.22 to 1.0 PgC/y, and of CO2 emission by estuaries to the atmosphere is 0.27 PgC/y. The estimates from the estuaries suffer from large uncertainties due to large variability and lack of systematic data collection. It is especially true for Southeast Asian estuaries as the biogeochemical cycling of material are different due to high atmospheric temperature, seasonality driven by monsoons, seasonal discharge etc. In order to quantify CO2 emissions from the Indian estuaries, samples were collected at 27 estuaries all along the Indian coast during discharge wet and dry periods. The emissions of CO2 to the atmosphere from Indian estuaries were 4-5 times higher during wet than dry period. The pCO2 ranged between ~300 and 18492 microatm which were within the range of world estuaries. The mean pCO2 and particulate organic carbon (POC) showed positive relation with rate of discharge suggesting availability of high quantities of organic matter that led to enhanced microbial decomposition. The annual CO2 fluxes from the Indian estuaries, together with dry period data available in the literature, amounts to 1.92 TgC which is >10 times less than that from the European estuaries. The low CO2 fluxes from the Indian estuaries are attributed to low flushing rates and less human settlements along the banks of the Indian estuaries.

Seasonal use of a New England estuary by foraging contingents of migratory striped bass

Science.gov (United States)

Mather, Martha E.; Pautzke, Sarah M.; Finn, John T.; Deegan, Linda A.; Muth, Robert M.

2011-01-01

Using acoustic telemetry on migratory striped bass Morone saxatilis in Plum Island Estuary (PIE), Massachusetts, we found that striped bass (335–634 mm total length) tagged in the spring and summer of 2005 (n = 14) and 2006 (n = 46) stayed in the estuary for an average of 66.0 d in 2005 and 72.2 d in 2006. Striped bass spent the most time in two specific reaches: middle Plum Island Sound and lower Rowley River. In both years, three different use-groups of striped bass were observed in PIE. Short-term visitors (n = 24) stayed in the estuary only briefly (range = 5–20 d). Two groups of seasonal residents stayed for more than 30 d, either in the Rowley River (n = 14) or in Plum Island Sound (n = 22). Within PIE, the two seasonal-resident use-groups may be foraging contingents that learn how to feed efficiently in specific parts of the estuary. These distinct within-estuary use patterns could have different implications for striped bass condition and prey impact.

Microplastic in three urban estuaries, China

International Nuclear Information System (INIS)

Zhao, Shiye; Zhu, Lixin; Li, Daoji

2015-01-01

Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 μm nets, MPs in Jiaojiang, Oujiang Estuaries were quantified, as well as that in Minjiang Estuary responding to Typhoon Soulik. Polymer matrix was analyzed by Raman spectroscopy. MP (<5 mm) comprised more than 90% of total number plastics. The highest MPs density was found in Minjiang, following Jiaojiang and Oujiang. Fibers and granules were the primary shapes, with no pellets found. Colored MPs were the majority. The concentrations of suspended microplastics determine their bioavailability to low trophic organisms, and then possibly promoting the transfer of microplastic to higher trophic levels. Polypropylene and polyethylene were the prevalent types of MPs analyzed. Economic structures in urban estuaries influenced on MPs contamination levels. Typhoon didn't influence the suspended MP densities significantly. Our results provide basic information for better understanding suspended microplastics within urban estuaries and for managerial actions. - Highlights: • Suspended microplastic were investigated within three densely populated/developed urban estuaries, China. • Economical structures may contribute to the abundances of microplastic particles within the studied estuaries. • Typhoon Soulik didn't influence microplastic densities in the water column of Minjiang Estuary. • Microplastics (<5 mm in diameter) dominated more than 90% of the total plastic by number. - Suspended microplastics (MPs) levels were quantified within three urban estuaries, China. MPs densities were consistent with the urban economical structure, and that in Minjiang were unaffected by Typhoon.

Integrating management tools and concepts to develop an estuarine planning support system: A case study of the Humber Estuary, Eastern England.

Science.gov (United States)

Lonsdale, Jemma-Anne; Weston, Keith; Barnard, Steve; Boyes, Suzanne J; Elliott, Michael

2015-11-15

Estuaries are important because of their multiple uses and users which often makes them challenging to manage since management must strike a balance between the needs of users, the estuaries' ecological and economic value and the context of multiple legislative drivers. To facilitate management we have therefore developed an Estuarine Planning Support System (EPSS) framework using the Humber Estuary, Eastern England, as a case study which integrates the current legislation tools and concepts. This integrated EPSS framework is an improvement on previous approaches for assessing cumulative impacts as it takes into account legislative drivers, management tools and other mechanisms for controlling plans/projects specific to the estuary. It therefore enables managers and users to assess and address both the current state and the way in which a new industrial, port or urban development could impact an estuary in an accessible and understandable framework. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Study of heavy metal concentration and partitioning in the Estrela River: implications for the pollution in Guanabara Bay - SE Brazil

Directory of Open Access Journals (Sweden)

Carlos M. A. Rangel

2011-09-01

Full Text Available In this study, the geochemical analysis of ten sediment samples collected along the fluvial system of the Estrela River, which flows into the northern portion of Guanabara Bay, shows the presence of anthropogenic impacts in this area. Concentrations of Fe, Mn, Zn, Cu, Pb, Cr and Ni obtained were slightly higher, when compared with values found innatural environments. The particle size and organic matter content in most of the analyzed stations showed featuresnot conducive to the accumulation of pollutants due to the low organic matter content and the strong presence ofsand fraction. There was also the fractionation of heavy metals in sediments and it was found the prominence ofresidual and reducible phase, besides the significant occurrence of organic fractions in some analyzed stations. Thesefactors, thus, highlight the potential risks of contamination, where the metals associated with the organic phase canbecome bioavailable in processes of dissolution, provided by physico-chemical changes that can occur in this aquaticenvironment.Neste estudo, analises geoquímicas de dez amostras de sedimentos coletadas ao longo do sistema fluvial do rio Estrela, que deságua na porção norte da Baía de Guanabara, evidenciam a presença de impactos antropogênicos nesta área. As concentrações de Fe, Mn, Zn, Cu, Pb, Cr e Ni obtidas foram ligeiramente elevadas, quando comparados com valores encontrados em ambientes naturais. A granulometria e o teor de matéria orgânica na maioria dos pontos analisados mostraram características não favoráveis à acumulação destes poluentes devido à baixa concentração de matéria orgânica e à forte presença de fração areia. Realizou-se também o fracionamento dos metais pesados nos sedimentos e constatou-se a preeminência da fase residual e redutível, além da ocorrência significativa da fração orgânica em alguns pontos analisados. Estes fatores evidenciam, portanto, riscos potenciais de contamina

Collaborative Potential between National Estuary Programs ...

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Estuaries are among the most productive ecosystems in the world, providing unique habitat for freshwater and marine species as well as valuable social and economic benefits. The wealth of ecosystem goods and services from estuaries has led to growth and development of human communities in adjacent areas and an increase in human activities that can adversely affect water quality and critical habitat. Managing for sustainable estuaries requires a balance of environmental concerns with community social and economic values. This has created an opportunity to leverage Environmental Protection Agency (EPA) scientific knowledge and tools with National Estuary Program (NEP) planning and management expertise to address environmental challenges in important estuarine ecosystems. The non-regulatory National Estuary Program (NEP) was outlined in the Clean Water Act to provide stakeholders an opportunity to monitor and manage ‘nationally significant’ estuaries. Currently there are 28 estuaries in the NEP, broadly distributed across the Atlantic, Pacific and Gulf Coasts, and in Puerto Rico. The local NEP management conferences must address a variety of environmental issues, from water quality and natural resources to coastal and watershed development. While the underlying objectives of each NEP are quite similar, each has unique landscapes, land uses, waterbodies, habitats, biological resources, economies and social culture. Consequently, the effects and severity of anthr

Differential impact of lytic viruses on prokaryotic morphopopulations in a tropical estuarine system (Cochin estuary, India).

Science.gov (United States)

Jasna, Vijayan; Pradeep Ram, Angia Sriram; Parvathi, Ammini; Sime-Ngando, Telesphore

2018-01-01

Our understanding on the importance of viral lysis in the functioning of tropical estuarine ecosystem is limited. This study examines viral infection of prokaryotes and subsequent lysis of cells belonging to different morphotypes across a salinity gradient in monsoon driven estuarine ecosystem (Cochin estuary, India). High standing stock of viruses and prokaryotes accompanied by lytic infection rates in the euryhaline/mesohaline region of the estuary suggests salinity to have an influential role in driving interactions between prokaryotes and viruses. High prokaryotic mortality rates, up to 42% of prokaryote population in the pre-monsoon season is further substantiated by a high virus to prokaryote ratio (VPR), suggesting that maintenance of a high number of viruses is dependent on the most active fraction of bacterioplankton. Although myoviruses were the dominant viral morphotype (mean = 43%) throughout the study period, there was significant variation among prokaryotic morphotypes susceptible to viral infection. Among them, the viral infected short rod prokaryote morphotype with lower burst estimates (mean = 18 viruses prokaryote-1) was dominant (35%) in the dry seasons whereas a substantial increase in cocci forms (30%) infected by viruses with high burst size (mean = 31 viruses prokaryote-1) was evident during the monsoon season. Such preferential infections of prokaryotic morphopopulations with respect to seasons can have a strong and variable impact on the carbon and energy flow in this tropical ecosystem.

The use of 131I-radioiodine in diagnostic and treatment: estimated risk in Guanabara

International Nuclear Information System (INIS)

Calegaro, J.U.M.

1974-01-01

The 131 -radioiodine use in Guanabara area, during 1972-1973, is analysed. References are made to the radiation levels delivered to thyroid, bone marrow and gonads in a population of 27000 people examined by tracer techniques, 190 submitted to hyperthyroidism treatment and 50 treated for thyroid cancer. The pertinent literature gives some data concerning radiation induced cancer (leukaemia and thyroid cancer). By this, it was possible to estimate the probability of tumour occurrence in that population, assuming a linear relationship between dose and effect. The conclusions are the followings: 1 - there are many duties in this field at the present; 2 - the leukaemia incidence related to the 131-radioiodine use is negligible, either in diagnostic or therapeutic modalities; 3 - the possibility of thyroid tumors induced by radiation is real, specially in hyperthyroidism treatment; 4 - the use of tracer techniques that cause lower irradiation to the pacient is advisable, because it isn't possible to exclude thyroid carcinogenesis at this level [pt

The Mandovi and Zuari estuaries

Digital Repository Service at National Institute of Oceanography (India)

Shetye, S.R.; DileepKumar, M.; Shankar, D.

of their extensive use for fisheries, agriculture, transportation, dumping of waste, etc. The two estuaries have since continued to attract scientific curiosity over the years, thanks in large measure to support from national and local funding agencies. As a... made so far to simulate them in numerical models, and characteristics of stratification and mixing. These are followed by chapters that examine the fun- damentals of biology and chemistry of the estuaries. A distinct characteristic of the estuaries...

SANCOR estuaries programme 1982-1986

CSIR Research Space (South Africa)

SANCOR

1983-02-01

Full Text Available , such research will also aid in the rational management of estuaries. Estuaries on which research should be concentrated are identified and guidelines are given for project proposals and reporting....

About Estuary Data Mapper (EDM)

Science.gov (United States)

Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions.

Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)

Digital Repository Service at National Institute of Oceanography (India)

Shivaprasad, A.; Vinita, J.; Revichandran, C.; Reny, P.D.; Deepak, M.P.; Muraleedharan, K.R.; NaveenKumar, K.R.

immune from extended hypoxia/anoxia and maintaining the health of the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season...

Short-term variability of water quality and its implications on phytoplankton production in a tropical estuary (Cochin backwaters - India)

Digital Repository Service at National Institute of Oceanography (India)

Madhu, N.V.; Balachandran, K.K.; Martin, G.D.; Jyothibabu, R; Thottathil, S.D.; Nair, M.; Joseph, T.; Kusum, K.K.

, C.A., Martin, G.D & Nair, K.K.C., (2006). Impact of fresh water influx on microzooplankton mediated food web in a tropical estuary (Cochin backwaters - India). Estuarine, Coastal and Shelf Science, 69, 505 - 518. Madhu. N.V., Jyothibabu, R..., Y., Wetzel, R.L., Anderson, I.C., 1999. Spatial and temporal characteristics of nutrient and phytoplankton dynamics in the York River Estuary, Virginia: analyses of long-term data. Estuaries 22, 260-275. Srinivas. K, Revichandran, C., Maheswaran...

Effects of urbanisation on macroalgae and sessile invertebrates in southeast Australian estuaries

Science.gov (United States)

Fowles, Amelia E.; Stuart-Smith, Rick D.; Stuart-Smith, Jemina F.; Hill, Nicole A.; Kirkpatrick, Jamie B.; Edgar, Graham J.

2018-05-01

The influence of anthropogenic and environmental factors on the composition, cover and dominance of macroalgae and sessile invertebrates was assessed in three capital city estuaries in south-eastern Australia. Heavy metals and proximity to ports showed the strongest relationships to the distribution of sessile reef biota after accounting for natural environmental gradients. The densities of laminarian, fucoid, brown and red foliose algae were negatively correlated with heavy metals, both in Port Phillip Bay (Melbourne) and the Derwent (Hobart), while turf, filamentous algae and some invertebrates were favoured. Sydney Harbour possessed a different pattern, with the laminarian kelp Ecklonia radiata most abundant near the main shipping port, probably because of biotic interactions involving urchin grazing in the lower estuary. Identifying drivers of benthic community pattern represents a key challenge for effective conservation management, particularly for estuaries affected by multiple anthropogenic impacts.

Environmental fate of fungicides and other current-use pesticides in a central California estuary

Science.gov (United States)

Smalling, Kelly L.; Kuivila, Kathryn; Orlando, James L.; Phillips, Bryn M.; Anderson, Brian S.; Siegler, Katie; Hunt, John W.; Hamilton, Mary

2013-01-01

The current study documents the fate of current-use pesticides in an agriculturally-dominated central California coastal estuary by focusing on the occurrence in water, sediment and tissue of resident aquatic organisms. Three fungicides (azoxystrobin, boscalid, and pyraclostrobin), one herbicide (propyzamide) and two organophosphate insecticides (chlorpyrifos and diazinon) were detected frequently. Dissolved pesticide concentrations in the estuary corresponded to the timing of application while bed sediment pesticide concentrations correlated with the distance from potential sources. Fungicides and insecticides were detected frequently in fish and invertebrates collected near the mouth of the estuary and the contaminant profiles differed from the sediment and water collected. This is the first study to document the occurrence of many current-use pesticides, including fungicides, in tissue. Limited information is available on the uptake, accumulation and effects of current-use pesticides on non-target organisms. Additional data are needed to understand the impacts of pesticides, especially in small agriculturally-dominated estuaries.

Impact of seasonal changes in nutrient loading on distribution and activity of nitrifiers in a tropical estuary

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Vipindas, P. V.; Anas, Abdulaziz; Jayalakshmy, K. V.; Lallu, K. R.; Benny, P. Y.; Shanta, Nair

2018-02-01

Estuaries are ecologically important environments, which function as the reception point of nitrogenous inputs of terrestrial and anthropogenic origin. In the present study, we discuss the influence of nutrient characteristics on the distribution and activity of nitrifiers in the water column of Cochin Estuary (CE), a tropical estuary along the southeast Arabian Sea (SEAS). Nitrifying bacteria (i.e. Ammonia- (AOB) and nitrite- (NOB) -oxidizing bacteria), which were enumerated using fluorescent in situ hybridization (FISH), showed marked seasonality while maintaining the abundance within an order of 107 cells L-1. Denaturing Gradient Gel Electrophoresis (DGGE) analysis of AOB exhibited spatio-temporal adaptability without much variation. Nitrification rate in the CE ranged from 2.25 to 426.17 nmol N L-1 h-1 and it was 10-40 fold higher during the pre-monsoon compared with the monsoon. We attributed this increase to high nutrient availability during pre-monsoon due to low flushing rate of the estuary. The study shows that the distribution and activities of nitrifiers in the CE are modulated by the changes in nutrient concentration imparted by the monsoon-driven seasonal variation in river-water discharge and flushing.

Bioprospektif Perairan Berdasarkan Produktivitas : Studi Kasus Estuari Sungai Serayu Cilacap, Indonesia

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Nur Laila Rahayu

2017-08-01

Full Text Available The high changes of Serayu River land use is resulting the high of load particle sedimentation into the body of water. Turbidity will accumulate in the downstream or estuaries which would have an impact on biota, especially plankton as primary productivity and secondary productivity. This research is conducted with a survey method and purposive sampling technique. Estuary Serayu River is divided into 5 stations, starts from the nearest to the sea (1 with 26 ‰ salinity and the furthest stations from the sea (5 with 8 ‰ salinity. Samples of water and plankton are taken at the time of high tide and low tide every month, for 4 months (August, September, October, and November 2016. The obtained data is analyzed by PCA to study the environmental factors towards primary productivity and secondary productivity. Based on the research result environmental factors has relation waters estuary productivity of Serayu river on the highest and lowest tide those are lightness, level TSS and pH.

Variability in waterfowl distribution within hypertidal estuaries in relation to sediments

International Nuclear Information System (INIS)

Clark, N.A.; Evans, J.; Rehfisch, M.M.; Shepherd, M.

1993-01-01

The Severn and Mersey estuaries are two of Britain's most important sites for their waterfowl populations. It is therefore critical to fully understand the likely impacts of tidal power barrages on these populations in order to predict the long-term post-barrage populations that the estuaries could support. Previous studies have enabled four years of monitoring to be carried out on both estuaries using identical methodology. These studies have shown that there is a considerable degree of consistency in the waterfowl populations in some areas, although apparently less so in other areas. Studies of sediment mobility have not been carried out in ways which enable direct comparison of changes in sediment with changes in bird populations. This latest study was planned to permit such a comparison and to provide five years of detailed counts on the Severn and four years on the Mersey on the low tide distribution of waterfowl populations. (author)

The nature and source of irregular discharges to stormwater entering Sydney estuary, Australia

International Nuclear Information System (INIS)

Beck, H.J.; Birch, G.F.

2014-01-01

Irregular discharges of polluted stormwater into drainage systems during base flow (no rainfall) result in acute ecological impacts within fluvial and estuarine environments. In this study, metal and TSS concentrations were significantly more variable during business hours of weekdays (i.e. high-business activity) than weekends/public holidays (i.e. low-business activity) within three highly-urbanised catchments of Sydney estuary (Australia), as determined by analysing multivariate dispersion (PERMDISP). Concentrations of TSS and all metals analysed (Al, Ca, Cu, Fe, Mg, Pb and Zn) were also significantly greater during high- than low-business periods within at least one of the three catchments. In no case were concentrations significantly higher during low- than high-business periods. This pattern of contamination supports the hypothesis that commercial and industrial sources are major contributors of irregular discharges of contamination to Sydney estuary. Irregular discharges and consequential ecological impacts may be effectively reduced in this environment by focussing management efforts on these activities. - Highlights: • Irregular discharges of pollution have acute impacts on aquatic ecosystems. • These discharges were thought to be made during low activity periods, such as night. • Pollution was more concentrated and erratic during high- than low-business periods. • Timing of pollution suggests commercial and industrial activities are major sources. • Discharges effectively reduced by managing commercial and industrial activities. - Previously unreported irregular, illegal discharges of polluted stormwater released to estuaries result in acute ecological impacts and are potentially related to commercial/industrial activities

Restoring fish ecological quality in estuaries: Implication of interactive and cumulative effects among anthropogenic stressors.

Science.gov (United States)

Teichert, Nils; Borja, Angel; Chust, Guillem; Uriarte, Ainhize; Lepage, Mario

2016-01-15

Estuaries are subjected to multiple anthropogenic stressors, which have additive, antagonistic or synergistic effects. Current challenges include the use of large databases of biological monitoring surveys (e.g. the European Water Framework Directive) to help environmental managers prioritizing restoration measures. This study investigated the impact of nine stressor categories on the fish ecological status derived from 90 estuaries of the North East Atlantic countries. We used a random forest model to: 1) detect the dominant stressors and their non-linear effects; 2) evaluate the ecological benefits expected from reducing pressure from stressors; and 3) investigate the interactions among stressors. Results showed that largest restoration benefits were expected when mitigating water pollution and oxygen depletion. Non-additive effects represented half of pairwise interactions among stressors, and antagonisms were the most common. Dredged sediments, flow changes and oxygen depletion were predominantly implicated in non-additive interactions, whereas the remainder stressors often showed additive impacts. The prevalence of interactive impacts reflects a complex scenario for estuaries management; hence, we proposed a step-by-step restoration scheme focusing on the mitigation of stressors providing the maximum of restoration benefits under a multi-stress context. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterizing seston in the Penobscot River Estuary.

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Meseck, Shannon L; Li, Yaqin; Sunila, Inke; Dixon, Mark; Clark, Paul; Lipsky, Christine; Stevens, Justin R; Music, Paul; Wikfors, Gary H

2017-10-01

The Penobscot River Estuary is an important system for diadromous fish in the Northeast United States of American (USA), in part because it is home to the largest remnant population of Atlantic salmon, Salmo salar, in the country. Little is known about the chemical and biological characteristics of seston in the Penobscot River Estuary. This study used estuarine transects to characterize the seston during the spring when river discharge is high and diadromous fish migration peaks in the Penobscot River Estuary. To characterize the seston, samples were taken in spring 2015 for phytoplankton identification, total suspended matter (TSM), percent organic TSM, chlorophyll a, particle size (2 μm-180 μm), particulate carbon and nitrogen concentrations, and stable carbon and nitrogen isotopes. The estuarine profiles indicate that TSM behaved non-conservatively with a net gain in the estuary. As phytoplankton constituted only 1/1000 of the particles, the non-conservative behavior of TSM observed in the estuary was most likely not attributable to phytoplankton. Particulate carbon and nitrogen ratios and stable isotope signals indicate a strong terrestrial, allochthonous signal. The seston in the Penobscot River Estuary was dominated by non-detrital particles. During a short, two-week time period, Heterosigma akashiwo, a phytoplankton species toxic to finfish, also was detected in the estuary. A limited number of fish samples, taken after the 2015 Penobscot River Estuary bloom of H. akashiwo, indicated frequent pathological gill damage. The composition of seston, along with ichthyotoxic algae, suggest the need for further research into possible effects upon resident and migratory fish in the Penobscot River Estuary. Published by Elsevier Ltd.

A model to predict the level of artificial radionuclides in environmental materials in the Severn Estuary and the Bristol Channel

International Nuclear Information System (INIS)

McColl, N.P.

1988-01-01

The NRPB SEVERN compartment model, of the Bristol Channel and Severn Estuary, has been developed for used in predicting environmental concentrations of artificial radionuclides present in the estuary. A comparison between predicted and measured values of salinity and environmental 137 Cs concentrations has demonstrated the overall validity of the model. SEVERN has been used to assess the radiological impact of radionuclides present in the estuary which result from low-level routine discharges from the nuclear power industry. (author)

Spatial distribution of trace elements in the surface sediments of a major European estuary (Loire Estuary, France): Source identification and evaluation of anthropogenic contribution

Science.gov (United States)

Coynel, Alexandra; Gorse, Laureline; Curti, Cécile; Schafer, Jörg; Grosbois, Cécile; Morelli, Guia; Ducassou, Emmanuelle; Blanc, Gérard; Maillet, Grégoire M.; Mojtahid, Meryem

2016-12-01

sediment quality in the Loire Estuary. The overall mean Effect Range Median quotients (m-ERM-q) results suggested that the Loire Estuary is mainly characterized by slightly toxic sediments even if ecotoxicological impacts have been previously reported on biota.

Provision of ecosystem services by human-made structures in a highly impacted estuary

International Nuclear Information System (INIS)

Layman, Craig A; Jud, Zachary R; Archer, Stephanie K; Riera, David

2014-01-01

Water filtration is one of the most important ecosystem services provided by sessile organisms in coastal ecosystems. As a consequence of increased coastal development, human-made shoreline structures (e.g., docks and bulkheads) are now common, providing extensive surface area for colonization by filter feeders. We estimate that in a highly urbanized sub-tropical estuary, water filtration capacity supported by filter feeding assemblages on dock pilings accounts for 11.7 million liters of water h −1 , or ∼30% of the filtration provided by all natural oyster reef throughout the estuary. Assemblage composition, and thus filtration capacity, varied as a function of piling type, suggesting that the choice of building material has critical implications for ecosystem function. A more thorough depiction of the function of coastal ecosystems necessitates quantification of the extensive ecosystem services associated with human-made structures. (paper)

Águas com predominância de Eutreptia lanowi steuer e Chlamydomonas reinhardi dangeard no plancton, na enseada de Inhauma, Baía de Guanabara

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Lejeune P. H. de Oliveira

1962-03-01

Full Text Available In brackish waters of a creek of Guanabara Bay, the author points by the first time the presence of Chlamydomonas reinhardi, Eutreptia lanowi, Oscillatoria putrida, O. limosa, O. chlorina that were unknown in our waters; such biologic indicators proved themselves pollutional conditions, so bad a stark-mesosaprobic regime. Other news are plankton analysis by the Standar methods, of two most expressive samples of water masses;also the mobility of the plankters are measured in micra by second.

Reservoir impacts downstream in highly regulated river basins: the Ebro delta and the Guadalquivir estuary in Spain

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M. J. Polo

2016-05-01

Full Text Available Regulation by reservoirs affects both the freshwater regime and the sediment delivery at the area downstream, and may have a significant impact on water quality in the final transitional water bodies. Spain is one the countries with more water storage capacity by reservoirs in the world. Dense reservoir networks can be found in most of the hydrographic basins, especially in the central and southern regions. The spatial redistribution of the seasonal and annual water storage in reservoirs for irrigation and urban supply, mainly, has resulted in significant changes of water flow and sediment load regimes, together with a fostered development of soil and water uses, with environmental impacts downstream and higher vulnerability of these areas to the sea level rise and drought occurrence. This work shows these effects in the Guadalquivir and the Ebro River basins, two of the largest regulated areas in Spain. The results show a 71 % decrease of the annual freshwater input to the Guadalquivir River estuary during 1930–2014, an increase of 420 % of the irrigated area upstream the estuary, and suspended sediment loads up to 1000 % the initial levels. In the Ebro River delta, the annual water yield has decreased over a 30 % but, on the contrary, the big reservoirs are located in the main stream, and the sediment load has decreased a 99 %, resulting in a delta coastal regression up to 10 m per year and the massive presence of macrophytes in the lower river. Adaptive actions proposed to face these impacts in a sea level rise scenario are also analyzed.

Spatial distribution of heavy metals in surficial sediments from Guanabara Bay: Rio de Janeiro, Brazil

Science.gov (United States)

Neto, José Antônio Baptista; Gingele, Franz Xaver; Leipe, Thomas; Brehme, Isa

2006-04-01

Ninety-two surface sediment samples were collected in Guanabara Bay, one of the most prominent urban bays in SE Brazil, to investigate the spatial distribution of anthropogenic pollutants. The concentrations of heavy metals, organic carbon and particle size were examined in all samples. Large spatial variations of heavy metals and particle size were observed. The highest concentrations of heavy metals were found in the muddy sediments from the north western region of the bay near the main outlets of the most polluted rivers, municipal waste drainage systems and one of the major oil refineries. Another anomalous concentration of metals was found adjacent to Rio de Janeiro Harbour. The heavy metal concentrations decrease to the northeast, due to intact rivers and the mangrove systems in this area, and to the south where the sand fraction and open-marine processes dominate. The geochemical normalization of metal data to Li or Al has also demonstrated that the anthropogenic input of heavy metals have altered the natural sediment heavy metal distribution.

Paleoenvironment interpretation of a 1760 years B.P. old sediment in a mangrove area of the Bay of Guanabara, using pollen analysis

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Barth Ortrud M.

2006-01-01

Full Text Available A sediment sample was obtained at 122 cm from the top of a drilling core in the Guapimirim mangrove, Bay of Guanabara, and analyzed using pollen analysis. This muddy core reached a sandy ground at 133 cm. 14C datation got the age of 1760 ? 50 years B.P. The most frequent pollen grains were mangrove species of Rhizophora mangle, Laguncularia racemosa and Avicennia schaueriana. "Restinga" and tropical rain forest vegetation was recognized behind the mangrove. After the last sea transgression at 2500 years B.P., the water level lowered to its actual size, allowing the installation of this mangrove.

Carbon budgets for two Portuguese estuaries: implications for the management and conservation of coastal waters

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Ana P. Oliveira

2014-07-01

The results presented illustrate that Tagus and Sado estuaries represent an important land/ocean boundary for carbon transformation and emission, and confirm the anthropogenic pressure that these estuaries are subject to. Carbon budgets vary markedly within and between these two estuaries reflecting the human pressure. Anthropogenic inputs, autochthonous carbon production and primary production are indicated as the main responsible for the carbon production within the estuaries. Both estuaries export carbon to the ocean and to the atmosphere. The inorganic carbon faction has a major role in the carbon budget, enriching the ocean in carbon dioxide, contributing this for the greenhouse effect. Our understanding of organic and inorganic carbon fluxes in Tagus and Sado estuaries is vital for an efficient protection and preservation of such ecosystems being helpful in limit human-caused damage and in restoring damaged estuarine/coastal ecosystems. In addition, the economic impact of the carbon fluxes to the atmosphere, estimated as €375,000 per year, creates the appropriate incentives to reduce emissions and shift them to higher-value uses. Suggesting, therefore, a coastal management re-oriented towards a more adaptive approach through the use of carbon market-based policies. This study is a contribution to the integration of coastal and global carbon cycles. However, additional efforts are required to fully merge other components subsystems, such as salt marshes, with these budgets. Moreover, a fully comprehension of the community metabolism in these estuaries will greatly improve this integration.

Estrutura da vegetação em florestas de mangue do estuário do rio Paraíba do Sul, Estado do Rio de Janeiro, Brasil Vegetation structure of the mangrove forest at the estuary Paraíba do Sul river, Rio de Janeiro, Brazil

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Elaine Bernini

2004-09-01

Full Text Available A estrutura da vegetação do manguezal do estuário do rio Paraíba do Sul foi analisada pelo método de parcelas, que foram distribuídas na franja e no interior da floresta em dois sítios de estudo. No geral, considerando-se os indivíduos > 1m alt., a altura média variou de 6,3 a 9,9m, o DAP médio de 7,44 a 13,4cm, a área basal média de 14,5 a 35,3m².ha-1 e a densidade média de 1.920 a 3.400 troncos.ha-1. Estes parâmetros estruturais não diferiram, significativamente, entre a franja e o interior da floresta, mas a contribuição de cada espécie variou entre as distintas zonas. Avicennia germinans (L. Stearn. foi a espécie dominante em área basal de indivíduos vivos (60%, seguida de Rhizophora mangle L. (25% e de Laguncularia racemosa (L. Gaertn. (15%. Os resultados obtidos demonstraram que a área de manguezal analisada apresenta melhor desenvolvimento estrutural quando comparada a outros manguezais do litoral fluminense, tais como os encontrados nas Baías de Guanabara e Sepetiba.A structural analysis of the mangrove forest at the Paraíba do Sul river estuary was performed using the stand method. The stands were demarcated in two points both at the forest edge and interior. The results indicate that average height varied from 6.3 to 9.9m; DBH varied from 7.44 to 13.4cm; average basal area varied from 14.5 to 35.3m².ha-1, and average density varied from 1,920 to 3,400 trunks.ha-1 (trees > 1m height. These structural parameters did not differ between the edge and the interior, but the contribution of each species varied between the zones. Avicennia germinans (L. Stearn. was the dominant species (60%, followed by Rhizophora mangle L. (25%, and Laguncularia racemosa (L. Gaertn. (15%. These results demonstrate that the mangroves forest at the Paraíba do Sul estuary has a better structural development than other mangrove sites found in the Rio de Janeiro State (e.g., those mangrove forests located at the Sepetiba and Guanabara

The Effect of Low Energy Turbulence in Estuary Margins on Fine Sediment Settling

Science.gov (United States)

Allen, R. M.; MacVean, L. J.; Tse, I.; Mazzaro, L. J.; Stacey, M. T.; Variano, E. A.

2014-12-01

Sediment dynamics in estuaries and near shore regions control the growth or erosion of the bed and fringing wetlands, determine the spread of sediment-associated contaminants, and limit the light availability for primary productivity through turbidity. In estuaries such as San Francisco Bay, this sediment is often cohesive, and can flocculate. Changes to the composition of the sediment and waters, the suspended sediment concentration, and the turbulence can all affect the flocculation of suspended sediment. In turn, flocculation controls the particle diameter, settling velocity, density, and particle inertia. These sediment properties drive the turbulent diffusivity, which balances with the settling velocity to impact the vertical distribution of sediment in the water column. The vertical profile strongly affects how sediment is transported through the estuary by lateral flow. Turbulence may also impact settling velocity in non-cohesive particles. In turbulence, dense particles may get trapped in convergent flow regions, thus particles are more likely to get swept along the downward side of a turbulent eddy than the upward side, resulting in enhanced settling velocities. We isolated the impacts of turbulence level, particle size and type, and suspended sediment concentration on particle settling velocities using uniform grain size particles in homogeneous isotropic turbulence. Controlling the turbulence in a well-defined turbulence tank, we used Two Acoustic Doppler Velocimeters, separated vertically, to measure turbulent velocities (w') and suspended sediment concentrations (C), which yield condition dependent settling velocities (ws), via equation 1. Lab characterization of particle settling velocities help to validate the method for measuring settling velocities in the field, and will serve as a foundation for an extensive field experiment in San Francisco Bay. Characterizing the velocity enhancement relative to the Stokes number, the Rouse number, and the

What happens in an estuary doesn't stay there: patterns of biotic connectivity resulting from long term ecological research

Science.gov (United States)

Mather, Martha E.; Finn, John T.; Kennedy, Christina G.; Deegan, Linda A.; Smith, Joseph M.

2013-01-01

The paucity of data on migratory connections and an incomplete understanding of how mobile organisms use geographically separate areas have been obstacles to understanding coastal dynamics. Research on acoustically tagged striped bass (Morone saxatilis) at the Plum Island Ecosystems (PIE) Long Term Ecological Research site, Massachusetts, documents intriguing patterns of biotic connectivity (i.e., long-distance migration between geographically distinct areas). First, the striped bass tagged at PIE migrated southward along the coast using different routes. Second, these tagged fish exhibited strong fidelity and specificity to PIE. For example, across multiple years, tagged striped bass resided in PIE waters for an average of 1.5-2.5 months per year (means: 51-72 days; range 2-122 days), left this estuary in fall, then returned in subsequent years. Third, this specificity and fidelity connected PIE to other locations. The fish exported nutrients and energy to at least three other coastal locations through biomass added as growth. These results demonstrate that what happens in an individual estuary can affect other estuaries. Striped bass that use tightly connected routes to feed in specific estuaries should have greater across-system impacts than fish that are equally likely to go anywhere. Consequently, variations in when, where, and how fish migrate can alter across-estuary impacts.

Changes in a temperate estuary during the filling of the biggest European dam.

Science.gov (United States)

Morais, Pedro; Chícharo, Maria Alexandra; Chícharo, Luís

2009-03-15

This study aimed to determine whether and how the disruption of river flow, during the filling of the Alqueva dam, influenced the variability of abiotic and biotic factors in the Guadiana estuary, particularly the abundance and distribution of anchovy eggs. River inflow was found to be the most important factor in determining abiotic and biotic variability in the Guadiana estuary. Seasonal patterns were obscured by long periods of low inflow (mid April to early December 2002), which caused marked changes in the estuary. The estuarine turbidity maximum zone was displaced towards the upper estuary, to at least 38 km from the river mouth, 8 to 16 km upstream from previous records. The dynamics of nutrient stoichiometry was also affected. In the upper and middle estuary, P was more potential limiting than N and potential Si limitation was only frequent on the coast, with direct and/or indirect influence in changing phytoplankton dynamics and composition. Previously, the upper estuary alternated between potential P limitation during winter, Si limitation during spring and mid summer and N limitation during mid summer and autumn. The flooding of vast areas in the catchment of the dam probably caused the increase of DSi concentrations, as well as maximal N and P loadings. The abundance of larval stages of anchovy decreased, putatively because estuarine productivity has also decreased. In April 2002 there was an uncontrolled discharge from the Alqueva dam, which reduced the abundance of anchovy eggs by 99.99%. It is suggested that dam managers should mimic, as much as possible, the natural river flow, in order to minimize the impact on downstream ecosystems. Management efforts should not be restricted to the areas upstream of the dam, but should also encompass the estuary and adjacent coastal area.

O MARKETING SOCIAL COMO DIFERENCIAL COMPETITIVO: O CASO DA EMPRESA EXPRESSO GUANABARA

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Patrícia Grenfell Oliveira

2015-12-01

Full Text Available Nos últimos anos as organizações têm demonstrado grande preocupação com as questões sociais e os conflitos ambientais que cercam nossa sociedade. Neste contexto surge o conceito de responsabilidade social e o marketing social, como um campo de atuação inspirado na ideia de sustentabilidade, capaz de alavancar a imagem e a marca da organização, além de ser uma diferencial perante seus concorrentes. Desta forma, a presente pesquisa teve como principal objetivo verificar a percepção dos clientes da Empresa Expresso Guanabara sobre o marketing social como diferencial competitivo. Trata-se de uma pesquisa com abordagem quali-quantitativa, de cunho exploratório e descritivo, fazendo uso do método estudo de caso. O marketing social pode ser visto como um diferencial competitivo que visa favorecer a organização e sua imagem perante seus stakeholders. Os resultados evidenciam que os clientes da empresa ainda não utilizam seus serviços pelo fato desta ser socialmente responsável e desenvolver estratégias de marketing social. Desta forma, concluir-se que na empresa estudada o marketing social ainda não é compreendido como um diferencial competitivo perante seus clientes e gestores.

O MARKETING SOCIAL COMO DIFERENCIAL COMPETITIVO: O CASO DA EMPRESA EXPRESO GUANABARA

Directory of Open Access Journals (Sweden)

Patrícia Grenfell Oliveira

2015-12-01

Full Text Available Nos últimos anos as organizações têm demonstrado grande preocupação com as questões sociais e os conflitos ambientais que cercam nossa sociedade. Neste contexto surge o conceito de responsabilidade social e o marketing social, como um campo de atuação inspirado na ideia de sustentabilidade, capaz de alavancar a imagem e a marca da organização, além de ser uma diferencial perante seus concorrentes. Desta forma, a presente pesquisa teve como principal objetivo verificar a percepção dos clientes da Empresa Expresso Guanabara sobre o marketing social como diferencial competitivo. Trata-se de uma pesquisa com abordagem quali-quantitativa, de cunho exploratório e descritivo, fazendo uso do método estudo de caso. O marketing social pode ser visto como um diferencial competitivo que visa favorecer a organização e sua imagem perante seus stakeholders. Os resultados evidenciam que os clientes da empresa ainda não utilizam seus serviços pelo fato desta ser socialmente responsável e desenvolver estratégias de marketing social. Desta forma, concluir-se que na empresa estudada o marketing social ainda não é compreendido como um diferencial competitivo perante seus clientes e gestores.

A saúde e os riscos dos pescadores e catadores de caranguejo da Baía de Guanabara The health and risks of fishermen and crab catchers of Guanabara Bay

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Márcia Ferreira Mendes Rosa

2010-06-01

Full Text Available O artigo discute a saúde, os riscos e o trabalho dos pescadores e catadores de caranguejo da região da APA de Guapimirim na Baía de Guanabara. Eles são típicos trabalhadores informais, sem proteção e garantias trabalhistas. Estão expostos a vários riscos no seu dia a dia, como acidentes com embarcações, com os apetrechos de pesca, com o próprio pescado, afogamentos, além de estarem expostos à grande radiação e variações climáticas. Há ainda a sobrecarga de peso e trabalho e a própria atividade noturna que potencializa mais os riscos. A partir de uma amostra de cem trabalhadores, que relataram por meio de uma pesquisa exploratória e descritiva de abordagem quanti-qualitativa, traçou-se um perfil dos mesmos. São trabalhadores que possuem baixa escolaridade, predominando o primeiro grau incompleto (63% e com 12% do total de analfabetos. Uma parcela desses trabalhadores (44% relataram possuir doenças ou agravos à saúde. Essas doenças estão relacionadas à sobrecarga de peso, à grande jornada de trabalho e todas as situações de periculosidade a que estão expostos em suas atividades. Foram identificadas grandes dificuldades desses trabalhadores em realizar o seu labor, havendo a necessidade urgente de encontrar medidas que possam melhorar suas condições de trabalho e vida.The article discusses the health, risks and the work of fishermen and crab catchers in region of APA Guapimirim in Guanabara Bay. Fishermen and crab catchers are typical informal workers, they suffer from lack of protection and working guarantee. They are exposed to working risks day by day such as accidents with fishing boat, fishing equipment, the own fish, drowning, as well as a lot of radiation and climatic variation. There are still the weight and work overload, as well as the activities done at night that increase the potential risks. A sample of 100 fishermen and crab catchers had told by quantitative-qualitative research that it was possible

Tidal impact on the dynamic behavior of dissolved pharmaceuticals in the Yangtze Estuary, China.

Science.gov (United States)

Zhao, Heng; Zhou, Jun Liang; Zhang, Jing

2015-12-01

The dynamic behavior of 24 dissolved pharmaceuticals over tidal cycles in the Yangtze Estuary, China was studied to assess the tidal impact on the fate of pharmaceutical residues. The results show that most pharmaceuticals were frequently detected with concentrations from below detection to 27.2 ng/L, with sulfamethoxazole, sulfamethazine, erythromycin, thiamphenicol and florfenicol dominating. During tidal cycles, pharmaceutical concentrations decreased during tidal rise, then increasing during tidal receding for all locations, except at site S2 which showed an opposite trend due to unique water movement there. It was observed that most compounds showed a non-conservative behavior, while diazepam and sulfamethoxazole displayed a conservative behavior. The pharmaceutical concentrations were found to increase with dissolved organic carbon (DOC) concentration, suggesting DOC as a carrier of pharmaceuticals. In addition, many compounds showed a significant negative relationship with suspended particulate matter (SPM) concentration, indicating SPM-water interactions as a control of pharmaceutical behavior in estuarine environment. Copyright © 2015 Elsevier B.V. All rights reserved.

The relationship between sediment and plutonium budgets in a small macrotidal estuary: Esk Estuary, Cumbria, UK

International Nuclear Information System (INIS)

Kelly, M.; Emptage, M.; Mudge, S.; Bradshaw, K.; Hamilton-Taylor, J.

1991-01-01

During a spring tide, measurements were made of sediment and 239,240 Pu discharges through a cross-section of the Esk estuary. These indicated that over the full tidal cycle, the inner estuary had a net gain of ca. 18 t of sediment and ca. 85 MBq of particulate phase 239,240 Pu, and a probable net loss of ca. 1 to 2 MBq of solution phase 239,240 Pu. Each of these was the net result of large gross discharges of sediment and plutonium into and out of the estuary for which the sea was the main source, with eroded estuarine sediment providing an additional minor source of sediment, of particulate phase plutonium and, via desorption, of solution phase plutonium. A net input with each tide, of sediment and its associated radionuclides, is considered to be typical for the Esk estuary under the normal conditions of low river flows. (author)

Establishing nursery estuary otolith geochemical tags for Sea Bass (Dicentrarchus labrax): Is temporal stability estuary dependent?

Science.gov (United States)

Ryan, Diarmuid; Wögerbauer, Ciara; Roche, William

2016-12-01

The ability to determine connectivity between juveniles in nursery estuaries and adult populations is an important tool for fisheries management. Otoliths of juvenile fish contain geochemical tags, which reflect the variation in estuarine elemental chemistry, and allow discrimination of their natal and/or nursery estuaries. These tags can be used to investigate connectivity patterns between juveniles and adults. However, inter-annual variability of geochemical tags may limit the accuracy of nursery origin determinations. Otolith elemental composition was used to assign a single cohort of 0-group sea bass Dicentrarchus labrax to their nursery estuary thus establishing an initial baseline for stocks in waters around Ireland. Using a standard LDFA model, high classification accuracies to nursery sites (80-88%) were obtained. Temporal stability of otolith geochemical tags was also investigated to assess if annual sampling is required for connectivity studies. Geochemical tag stability was found to be strongly estuary dependent.

Conditions for tidal bore formation in convergent alluvial estuaries

Science.gov (United States)

Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

2016-04-01

Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

Community structure of elasmobranchs in estuaries along the northwest Gulf of Mexico

Science.gov (United States)

Plumlee, Jeffrey D.; Dance, Kaylan M.; Matich, Philip; Mohan, John A.; Richards, Travis M.; TinHan, Thomas C.; Fisher, Mark R.; Wells, R. J. David

2018-05-01

structure. Diversity was greatest in mid-latitudinal estuaries with spatially and temporally dynamic salinity regimes. As environmental change and human impacts persist across much of the world, understanding environmental drivers of community structure using long-term datasets will provide insight to how these changes influence coastal ecosystems, and enable more comprehensive and scale-independent models to be developed for the management and conservation of coastal ecotones.

Impact of discards of beam trawl fishing on the nematode community from the Tagus estuary (Portugal)

Energy Technology Data Exchange (ETDEWEB)

Franco, M.A. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium); Oceanography Institute, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Steyaert, M. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium); Cabral, H.N. [Oceanography Institute, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Tenreiro, R.; Chambel, L. [Instituto de Ciencia Aplicada e Tecnologia, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Vincx, M. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium); Costa, M.J. [Oceanography Institute, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Vanaverbeke, J. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium)], E-mail: jan.vanaverbeke@ugent.be

2008-10-15

The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4 cm deep at four different moments in time post deposition (0, 2, 4 and 6 h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments.

Impact of discards of beam trawl fishing on the nematode community from the Tagus estuary (Portugal)

International Nuclear Information System (INIS)

Franco, M.A.; Steyaert, M.; Cabral, H.N.; Tenreiro, R.; Chambel, L.; Vincx, M.; Costa, M.J.; Vanaverbeke, J.

2008-01-01

The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4 cm deep at four different moments in time post deposition (0, 2, 4 and 6 h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments

Caracterização da Contaminação por Petróleo e seus Derivados na Baía de Guanabara: Aplicação de Técnicas Organogeoquímicas e Organopetrográficas

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João Graciano Mendonça Filho

2003-01-01

Full Text Available The Guanabara Bay is the second bigger bay of the Brazilian coast. The bay is oneof most beautiful of the world and shelters an ample and protected natural environment,preponderant factor for the development of the region. Due the pollution of this ecosys-tem, today, the bay represents an important focus of environmental interest. In order todeterminate the preservation degree of the organic components of bottom sediments from Guanabara Bay, ninety-two samples were collected from these sediments, however, pre-liminarily, twenty-five samples were analyzed. These twenty-five samples were submittedto techniques of organic geochemistry (Total Organic Carbon - TOC and Rock-Evalpyrolysis to determinate the amount and quality of the organic matter, and microscopy(transmitted white light and reflected ultraviolet light. The TOC values of the twenty-fivesamples range from 0.04 to 6.1% indicating the high preservation degree of the organicmatter. The Rock- Eval pyrolysis data show Hydrogen Index (HI values from 25 to 249mg HC/gCOT; S1 values ranges from 0,02 to 5,6 mg HC/gR; Production Index (PI rise up0,5. The results of the microscopy investigation showed that occur a predominance ofamorphous organic matte (AOM over the palynomorphs and phytoclasts. The liptiniticmaterial showed a light yellow-greenish yellow fluorescence color. The percentages ofAOM, the TOC values and fluorescence color indicate a high degree of preservation of theorganic matter. The integration of the results from organic geochemistry and microscopytechniques indicate that the sediments of the Baía de Guanabara present very high hydro-carbon pollution, deposited in dysoxic-anoxic environment.

Nutrients in some estuaries of Kerala

Digital Repository Service at National Institute of Oceanography (India)

Devi, K.S.; Venugopal, P.; Remani, K.N.; Zacharias, D.; Unnithan, R.V.

phosphate and ammonia were high at Kallai compared to other three estuaries. All the estuaries showed an increase in nitrate content during monsoon. Nitrite values were high in postmonsoon. Ammonia levels were generally high except at Korapuzha. Nutrient...

Superficial distribution of aromatic compounds and geomicrobiology of sediments from Suruí Mangrove, Guanabara Bay, RJ, Brazil

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Luiz F. Fontana

2010-12-01

Full Text Available The distribution of selected aromatic compounds and microbiology were assessed in superficial sediments from Suruí Mangrove, Guanabara Bay. Samples were collected at 23 stations, and particle size, organic matter, aromatic compounds, microbiology activity, biopolymers, and topography were determined. The concentration of aromatic compounds was distributed in patches over the entire mangrove, and their highest total concentration was determinated in the mangrove's central area. Particle size differed from most mangroves in that Suruí Mangrove has chernies on the edges and in front of the mangrove, and sand across the whole surface, which hampers the relationship between particle size and hydrocarbons. An average @ 10% p/p of organic matter was obtained, and biopolymers presented high concentrations, especially in the central and back areas of the mangrove. The biopolymers were distributed in high concentrations. The presence of fine sediments is an important factor in hydrocarbon accumulation. With high concentration of organic matter and biopolymers, and the topography with chernies and roots protecting the mangrove, calmer areas are created with the deposition of material transported by wave action. Compared to global distributions, concentrations of aromatic compounds in Suruí Mangrove may be classified from moderate to high, showing that the studied area is highly impacted.A distribuição de compostos aromáticos selecionados e a microbiologia foram avaliados em sedimentos superficiais do Manguezal de Suruí, Baía de Guanabara. Amostras foram coletadas em 23 pontos e determinados a granulometria, matéria orgânica, compostos aromáticos, atividade microbiológica, biopolímeros e a topografia. A concentração dos compostos aromáticos foi distribuída em manchas por todo o manguezal e sua concentração total mais elevada foi encontrada na área central do manguezal. A granulometria diferiu da maioria dos manguezais, uma vez que no

Computation of diffusion coefficients for waters of Gauthami Godavari estuary using one-dimensional advection-diffusion model

Digital Repository Service at National Institute of Oceanography (India)

Jyothi, D.; Murty, T.V.R.; Sarma, V.V.; Rao, D.P.

conditions. As the pollutant load on the estuary increases, the. water quality may deteriorate rapidly and therefore the scientific interests are centered on the analysis of water quality. The pollutants will be subjected to a number of physical, chemical... study we have applied one-dimensional advection-diffusion model for the waters of Gauthami Godavari estuary to determine the axial diffusion coefficients and thereby to predict the impact assessment. The study area (Fig. 1) is the lower most 32 km...

Socio-Economic Concerns and Essential Elements in Estuary Management Strategies; Haliç Case, Istanbul

Science.gov (United States)

Alpar, Bedri; Isil Cetin, Basak

2016-04-01

Estuaries are transitional areas between the land and sea and home to a large and growing proportion of the world's population. They are highly productive ecosystems which create jobs, and boosts local economic growth with a higher percentage of collective and private enterprises and a larger share of production. They serve many important socio-economic functions and therefore receive untreated urban wastes and riverine inputs and concentrate various pollutants coming from inland domestic, agricultural and industrial activities. Therefore such kinds of complex systems are highly vulnerable because they are usually the sink for the hinterlands. Due to serious environmental problems felt more intensively day by day, central and local governments must adopt an integrated policy and decision making process to promote a balance of uses. As surrounded by many historical attractions, heritage sites, buzzing cultural scenes and other natural resources, the Haliç (the Golden Horn estuary) offers great opportunities and has a vitality fed by widespread economic and cultural factors. The typical landscape of the estuary, its bridges, geomorphic features, oceanographic and hydrodynamic features of its waters, sea bottom characteristics, environmental pollution, make this estuary a critical marine environment which impacts to economy, environment and community. However, rapid urban growth and uncontrolled industrial development (1950-1985) led to a severe increase in pollution levels of its water and cohesive sediments. The siltation due to liquid and solid waste dumped by two streams caused anaerobic decomposition problems. In addition, the ecological processes occurring in the Haliç are rather complex as they are interacted with the socio-economic system. This study focuses on the essential elements of integrated coastal zone management for the Haliç, and its probable impacts to economy, environment and community. All objectives and probable impacts need to be integrated

Bar dimensions and bar shapes in estuaries

Science.gov (United States)

Leuven, Jasper; Kleinhans, Maarten; Weisscher, Steven; van der Vegt, Maarten

2016-04-01

Estuaries cause fascinating patterns of dynamic channels and shoals. Intertidal sandbars are valuable habitats, whilst channels provide access to harbors. We still lack a full explanation and classification scheme for the shapes and dimensions of bar patterns in natural estuaries, in contrast with bars in rivers. Analytical physics-based models suggest that bar length in estuaries increases with flow velocity, tidal excursion length or estuary width, depending on which model. However, these hypotheses were never validated for lack of data and experiments. We present a large dataset and determine the controls on bar shape and dimensions in estuaries, spanning bar lengths from centimeters (experiments) to 10s of kilometers length. First, we visually identified and classified 190 bars, measured their dimensions (width, length, height) and local braiding index. Data on estuarine geometry and tidal characteristics were obtained from governmental databases and literature on case studies. We found that many complex bars can be seen as simple elongated bars partly cut by mutually evasive ebb- and flood-dominated channels. Data analysis shows that bar dimensions scale with estuary dimensions, in particular estuary width. Breaking up the complex bars in simple bars greatly reduced scatter. Analytical bar theory overpredicts bar dimensions by an order of magnitude in case of small estuarine systems. Likewise, braiding index depends on local width-to-depth ratio, as was previously found for river systems. Our results suggest that estuary dimensions determine the order of magnitude of bar dimensions, while tidal characteristics modify this. We will continue to model bars numerically and experimentally. Our dataset on tidal bars enables future studies on the sedimentary architecture of geologically complex tidal deposits and enables studying effects of man-induced perturbations such as dredging and dumping on bar and channel patterns and habitats.

Unbounded boundaries and shifting baselines: Estuaries and coastal seas in a rapidly changing world

Science.gov (United States)

Little, S.; Spencer, K. L.; Schuttelaars, H. M.; Millward, G. E.; Elliott, M.

2017-11-01

This Special Issue of Estuarine, Coastal and Shelf Science presents contributions from ECSA 55; an international symposium organised by the Estuarine and Coastal Sciences Association (ECSA) and Elsevier on the broad theme of estuaries and coastal seas in times of intense change. The objectives of the SI are to synthesise, hypothesise and illustrate the impacts of global change on estuaries and coastal seas through learning lessons from the past, discussing the current and forecasting for the future. It is highlighted here that establishing impacts and assigning cause to the many pressures of global change is and will continue to be a formidable challenge in estuaries and coastal seas, due in part to: (1) their complexity and unbounded nature; (2) difficulties distinguishing between human-induced changes and natural variations and; (3) multiple pressures and effects. The contributing authors have explored a number of these issues over a range of disciplines. The complexity and connectivity of estuaries and coastal seas have been investigated through studies of physicochemical and ecological components, whilst the human imprint on the environment has been identified through a series of predictive, contemporary, historical and palaeo approaches. The impact of human activities has been shown to occur over a range of spatial and temporal scales, requiring the development of integrated management approaches. These 30 articles provide an important contribution to our understanding and assessment of the impacts of global change. The authors highlight methods for essential management/mitigation of the consequences of global change and provide a set of directions, ideas and observations for future work. These include the need to consider: (1) the cumulative, synergistic and antagonistic effects of multiple pressures; (2) the importance of unbounded boundaries and connectivity across the aquatic continuum; (3) the value of combining cross-disciplinary palaeo, contemporary and

Occurrences of dissolved trace metals (Cu, Cd, and Mn) in the Pearl River Estuary (China), a large river-groundwater-estuary system

Science.gov (United States)

Wang, Deli; Lin, Wenfang; Yang, Xiqian; Zhai, Weidong; Dai, Minhan; Arthur Chen, Chen-Tung

2012-12-01

This study for the first time examined dissolved metals (Cu, Cd, and Mn) together with dissolved oxygen and carbonate system in the whole Pearl River Estuary system, from the upper rivers to the groundwater discharges until the estuarine zone, and explored their potential impacts in the adjacent northern South China Sea (SCS) during May-August 2009. This river-groundwater-estuary system was generally characterized by low dissolved metal levels as a whole, whilst subject to severe perturbations locally. In particular, higher dissolved Cu and Cd occurred in the North River (as high as 60 nmol/L of Cu and 0.99 nmol/L of Cd), as a result of an anthropogenic source from mining activities there. Dissolved Cu levels were elevated in the upper estuary near the city of Guangzhou (Cu: ˜40 nmol/L), which could be attributable to sewage and industrial effluent discharges there. Elevated dissolved metal levels (Cu: ˜20-40 nmol/L; Cd: ˜0.2-0.8 nmol/L) also occurred in the groundwaters and parts of the middle and lower estuaries, which could be attributable to a series of geochemical reactions, e.g., chloride-induced desorption from the suspended sediments, oxidation of metal sulfides, and the partial dissolution of minerals. The high river discharge during our sampling period (May-August 2009) significantly diluted anthropogenic signals in the estuarine mixing zone. Of particular note was the high river discharge (which may reach 18.5 times as high as in the dry season) that transported anthropogenic signals (as indicated by dissolved Cu and Cd) into the adjacent shelf waters of the northern SCS, and might have led to the usually high phytoplankton productivity there (chlorophyll-a value >10 μg/L).

Idade e crescimento de Callinectes danae e C. ornatus (Crustacea, Decapoda na Baía de Guanabara, Rio de Janeiro, Brasil Age and growth of Callinectes danae and C. ornatus (Crustacea, Decapoda in Guanabara Bay, Rio de Janeiro, Brazil

Directory of Open Access Journals (Sweden)

Karina A. Keunecke

2008-06-01

Full Text Available Callinectes danae Smith, 1869 e C. ornatus Ordway, 1863 constituem uma parcela importante da produção pesqueira na Baía de Guanabara. Ambas espécies compõem uma fração significativa da fauna-acompanhante sendo exaustivamente descartadas pelas pescarias de arrasto de camarões na costa brasileira. As curvas de crescimento de C. danae e C. ornatus foram calculadas por meio da análise de progressão modal. Para estimar os parâmetros biológicos, foi aplicado o modelo de crescimento de Bertalanffy e para estimar a longevidade foi usada a sua fórmula inversa. As curvas de crescimento foram: ♂ LC = 120 (1 - e -0,005t , ♀ LC = 113 (1 - e -0,005t; ♂ LC = 94 (1 - e -0,005t e ♀ LC = 110 (1 - e -0,005t , respectivamente para C. danae e C. ornatus. A longevidade alcançada para as duas espécies foi em torno de 2,5 anos, além de validar as curvas de crescimento. O estudo do crescimento em crustáceos é de extrema importância, pois além de fornecer a informação biológica básica para o grupo, os parâmetros estimados subsidiam o ordenamento e manejo pesqueiro das espécies exploradas.Callinectes danae Smith, 1869 and C. ornatus Ordway, 1863 constitute an important portion from the fishing products at Guanabara Bay. Both species compose a significant by-catch fraction being a lot discarded during shrimp trawlings along Brazilian coast. Growth curves were estimated by modal progression analysis. For the biological parameters it was applied the Bertalanffy growth function and for the age it was used its inverse formula. Growth curves of C. danae and C. ornatus were respectively: ♂ LC = 120 (1 - e -0,005t, ♀ LC = 113 (1 - e -0,005t; ♂ LC = 94 (1 - e -0,005t and ♀ LC = 110 (1 - e -0,005t. The age for both species reached around 2.5 years, besides to confirm growth curves. Growth study in crustaceans is very important, because besides supplying biological information it subsidizes fishery management for exploted species.

Bioconcentração e biomagnificação de metilmercúrio na baía de Guanabara, Rio de Janeiro

Directory of Open Access Journals (Sweden)

Helena A. Kehrig

2011-01-01

Full Text Available Methylmercury was determined in water and aquatic biota from Guanabara Bay. Trophic transfer of methylmercury was observed between trophic levels from prey (microplankton, mesoplankton and fish with different feeding habits to top predator (pelagic demersal fish. Top predator fish presented the highest methylmercury concentrations (320.3 ± 150.7 mg kg-1 dry wt., whereas microplankton presented the lowest (8.9 ± 3.3 mg kg-1 dry wt.. The successive amplification of methylmercury concentrations and its bioconcentration factor with increasing trophic levels from base to top indicate that biomagnification may be occurring along the food web. Results suggest the importance of feeding habits and trophic level in the bioaccumulation of methylmercury by aquatic biota.

Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity

Science.gov (United States)

Miselis, Jennifer L.; Andrews, Brian D.; Nicholson, Robert S.; Defne, Zafer; Ganju, Neil K.; Navoy, Anthony S.

2016-01-01

Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m3 of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.

The Estuary Guide. Level 3: High School. Draft.

Science.gov (United States)

Alexander, Glen; And Others

Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the high school level seeks to teach what estuaries are; provide opportunities to practice decision-making that affects estuaries; and encourage students to…

Particulate organic matter predicts bacterial productivity in a river dominated estuary

Science.gov (United States)

Crump, B. C.

2015-12-01

Estuaries act as coastal filters for organic and inorganic fluvial materials in which microbial, biogeochemical, and ecological processes combine to transform organic matter and nutrients prior to export to the coastal ocean. The function of this estuarine 'bioreactor' is linked to the residence times of those materials and to rates of microbial heterotrophic activity. Our ability to forecast the impact of global change on estuarine bioreactor function requires an understanding of the basic controls on microbial community activity and diversity. In the Columbia River estuary, the microbial community undergoes a dramatic seasonal shift in species composition during which a spring bacterioplankton community, dominated by Flavobacteriaceae and Oceanospirillales, is replaced by a summer community, dominated by Rhodobacteraceae and several common marine taxa. This annual shift occurs in July, following the spring freshet, when river flow and river chlorophyll concentration decrease and when estuarine water residence time increases. Analysis of a large dataset from 17 research cruises (1990-2014) showed that the composition of particulate organic matter in the estuary changes after the freshet with decreasing organic carbon and nitrogen content, and increasing contribution of marine and autochthonous estuarine organic matter (based on PO13C and pigment ratios). Bacterial production rates (measured as leucine or thymidine incorporation rates) in the estuary respond to this change, and correlate strongly with labile particulate nitrogen concentration and temperature during individual sampling campaigns, and with the concentration of chlorophyll in the Columbia River across all seasons. Regression models suggest that the concentration of labile particulate nitrogen and the rate of bacterial production can be predicted from sensor measurements of turbidity, salinity, and temperature in the estuary and chlorophyll in the river. These results suggest that the quality of

A comparative study on the internal dose due to Polonium-210 in the ecosystem of Athangarai estuary (Palk Strait) and Punnaikayal estuary (Gulf of Mannar), India

International Nuclear Information System (INIS)

Krishnamoorthy, R.; Ravikumar, S.; Shahul Hameed, P.

2006-01-01

The present study deals with Committed Effective Dose (CEO) due to 210 Po through the dietary intake of seafood from the Athangarai estuary and Punnaikayal estuary. The concentration of 210 Po was determined in selected species of estuarine organisms. It is found that the 210 Po dose due to the consumption of estuarine food varied from 49.9 to 552.1 μSv/y in Athangarai estuary and 148.0 to 406.9 μSv/y in Punnaikayal estuary. Concentration of 210 Po in the muscle of edible organisms in Athangarai estuary and Punnaikayal estuary ranged from 20.8 to 181.3 Bq/kg and 88.1 to 242.2 Bq/kg respectively. Higher 210 Po dose is expected via the consumption of fish Sandinella longiceps (552.1 μSv/y) in Athangarai estuary and Thyssa malabarica (406.9 μSv/y) in Punnaikayal estuary. In the present study higher level of 210 Po concentration was observed in Plankton feeding fish of both the estuary. (author)

Utilising monitoring and modelling of estuarine environments to investigate catchment conditions responsible for stratification events in a typically well-mixed urbanised estuary

Science.gov (United States)

Lee, Serena B.; Birch, Gavin F.

2012-10-01

Estuarine health is affected by contamination from stormwater, particularly in highly-urbanised environments. For systems where catchment monitoring is insufficient, novel techniques must be employed to determine the impact of urban runoff on receiving water bodies. In the present work, estuarine monitoring and modelling were successfully employed to determine stormwater runoff volumes and establish an appropriate rainfall/runoff relationship capable of replicating fresh-water discharge due to the full range of precipitation conditions in the Sydney Estuary, Australia. Using estuary response to determine relationships between catchment rainfall and runoff is a widely applicable method and may be of assistance in the study of waterways where monitoring fluvial discharges is not practical or is beyond the capacity of management authorities. For the Sydney Estuary, the SCS-CN method replicated rainfall/runoff and was applied in numerical modelling experiments investigating the hydrodynamic characteristics affecting stratification and estuary recovery following high precipitation. Numerical modelling showed stratification in the Sydney Estuary was dominated by fresh-water discharge. Spring tides and up-estuary winds contributed to mixing and neap tides and down-estuary winds enhanced stratification.

Mass balance in the monitoring of pollutants in tidal rivers of the Guanabara Bay, Rio de Janeiro, Brazil.

Science.gov (United States)

da Silveira, Raquel Pinhão; Rodrigues, Ana Paula de Castro; Santelli, Ricardo Erthal; Cordeiro, Renato Campello; Bidone, Edison Dausacker

2011-10-01

This study addressed the identification and monitoring of pollution sources of terrestrial origin in rivers (domestic sewage and industrial effluents) and critical fluvial segments in highly polluted environments under tidal influence (mixing marine and continental sources) from Guanabara Bay Basin, Rio de Janeiro, Brazil. The mass balance of contaminants was determined in conditions of continuous flow (low tide) during dry season (lower dilution capability). The results allowed the evaluation of the potential of contaminant mass generation by the different river segments and the estimation of their natural and anthropogenic components. The water quality of Iguaçú and Sarapuí Rivers were evaluated for metals and biochemical oxygen demand. The method gave an excellent response, including the possibility of sources identification and contaminated river segments ranking. The approach also offers fast execution and data interpretation, being highly efficient.

The impact of water quality changes on the socio-economic system of the Guadiana Estuary: an assessment of management options

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Mª Helena E. Guimarães

2012-09-01

Full Text Available Tourism related to bathing has a growing economic importance in the Guadiana Estuary in southern Spain and Portugal. Polls of local public opinion showed an awareness of potential and current threats to the aquatic environment posed by regulation of river flow and untreated/poorly-treated urban sewage discharge. Because of this strong concern for water quality, it was selected as the policy issue for our application of the Systems Approach Framework (SAF. We developed an integrated simulation model of the Guadiana estuarine system in which the ecological system and socioeconomic components are linked by means of beach eco-label (Blue Flag Award through its dependence on fecal bacterial thresholds. We quantified the socioeconomic impacts of water quality through an Economic Base Model that is used to portray the effect of increasing employment on resident population as a result of change in coastal water quality. A Cost-Benefit Analysis provides monetary indicators for scenario evaluation. It includes a monetary valuation of changes in water quality on human welfare using a Contingent Valuation Method. Because the population has a strong seasonal influence on the wastewater discharge into the estuary, we were able to simulate the feedback loop between the human activities that control water quality and those that benefit from it. We organized a critical evaluation of our efforts with the stakeholders, which allowed us to better understand their perceptions of the strengths, limitations, and opportunities for future SAF applications. Here we describe several aspects of our efforts that demonstrate the potential value of the SAF to environmental managers and stakeholders in clarifying some of the causal mechanisms, management options, and costs for resolution of the conflictual problem between water quality and tourism in the Guadiana estuary.

Regional acidification trends in Florida shellfish estuaries: A 20+ year look at pH, oxygen, temperature, and salinity

Science.gov (United States)

Robbins, Lisa L.; Lisle, John T.

2018-01-01

Increasing global CO2 and local land use changes coupled with increased nutrient pollution are threatening estuaries worldwide. Local changes of estuarine chemistry have been documented, but regional associations and trends comparing multiple estuaries latitudinally have not been evaluated. Rapid climate change has impacted the annual and decadal chemical trends in estuaries, with local ecosystem processes enhancing or mitigating the responses. Here, we compare pH, dissolved oxygen, temperature, and salinity data from 10 Florida shellfish estuaries and hundreds of shellfish bed stations. Over 80,000 measurements, spanning from 1980 to 2008, taken on Atlantic Ocean and West Florida coast showed significant regional trends of consistent pH decreases in 8 out of the 10 estuaries, with an average rate of decrease on the Gulf of Mexico side estuaries of Florida of 7.3 × 10−4 pH units year−1, and average decrease on the Atlantic Coast estuaries of 5.0 × 10−4 pH units year−1. The rates are approximately 2–3.4 times slower than observed in pH decreases associated with ocean acidification in the Atlantic and Pacific. Other significant trends observed include decreasing dissolved oxygen in 9 out of the 10 estuaries, increasing salinity in 6 out of the 10, and temperature increases in 3 out of the 10 estuaries. The data provide a synoptic regional view of Florida estuary trends which reflect the complexity of changing climate and coastal ocean acidification superimposed on local conditions. These data provide context for understanding, and interpreting the past and predicting future of regional water quality health of shellfish and other organisms of commercial and ecological significance along Florida’s coasts.

Regional acidification trends in Florida shellfish estuaries: A 20+ year look at pH, oxygen, temperature and salinity

Science.gov (United States)

Robbins, Lisa L.; Lisle, John T.

2018-01-01

Increasing global CO2 and local land use changes coupled with increased nutrient pollution are threatening estuaries worldwide. Local changes of estuarine chemistry have been documented, but regional associations and trends comparing multiple estuaries latitudinally have not been evaluated. Rapid climate change has impacted the annual and decadal chemical trends in estuaries, with local ecosystem processes enhancing or mitigating the responses. Here, we compare pH, dissolved oxygen, temperature, and salinity data from 10 Florida shellfish estuaries and hundreds of shellfish bed stations. Over 80,000 measurements, spanning from 1980 to 2008, taken on Atlantic Ocean and West Florida coast showed significant regional trends of consistent pH decreases in 8 out of the 10 estuaries, with an average rate of decrease on the Gulf of Mexico side estuaries of Florida of 7.3 × 10−4 pH units year−1, and average decrease on the Atlantic Coast estuaries of 5.0 × 10−4 pH units year−1. The rates are approximately 2–3.4 times slower than observed in pH decreases associated with ocean acidification in the Atlantic and Pacific. Other significant trends observed include decreasing dissolved oxygen in 9 out of the 10 estuaries, increasing salinity in 6 out of the 10, and temperature increases in 3 out of the 10 estuaries. The data provide a synoptic regional view of Florida estuary trends which reflect the complexity of changing climate and coastal ocean acidification superimposed on local conditions. These data provide context for understanding, and interpreting the past and predicting future of regional water quality health of shellfish and other organisms of commercial and ecological significance along Florida’s coasts.

Environmental flow assessments for transformed estuaries

Science.gov (United States)

Sun, Tao; Zhang, Heyue; Yang, Zhifeng; Yang, Wei

2015-01-01

Here, we propose an approach to environmental flow assessment that considers spatial pattern variations in potential habitats affected by river discharges and tidal currents in estuaries. The approach comprises four steps: identifying and simulating the distributions of critical environmental factors for habitats of typical species in an estuary; mapping of suitable habitats based on spatial distributions of the Habitat Suitability Index (HSI) and adopting the habitat aggregation index to understand fragmentation of potential suitable habitats; defining variations in water requirements for a certain species using trade-off analysis for different protection objectives; and recommending environmental flows in the estuary considering the compatibility and conflict of freshwater requirements for different species. This approach was tested using a case study in the Yellow River Estuary. Recommended environmental flows were determined by incorporating the requirements of four types of species into the assessments. Greater variability in freshwater inflows could be incorporated into the recommended environmental flows considering the adaptation of potential suitable habitats with variations in the flow regime. Environmental flow allocations should be conducted in conjunction with land use conflict management in estuaries. Based on the results presented here, the proposed approach offers flexible assessment of environmental flow for aquatic ecosystems that may be subject to future change.

Sediment Trapping in Estuaries

Science.gov (United States)

Burchard, Hans; Schuttelaars, Henk M.; Ralston, David K.

2018-01-01

Estuarine turbidity maxima (ETMs) are generated by a large suite of hydrodynamic and sediment dynamic processes, leading to longitudinal convergence of cross-sectionally integrated and tidally averaged transport of cohesive and noncohesive suspended particulate matter (SPM). The relative importance of these processes for SPM trapping varies substantially among estuaries depending on topography, fluvial and tidal forcing, and SPM composition. The high-frequency dynamics of ETMs are constrained by interactions with the low-frequency dynamics of the bottom pool of easily erodible sediments. Here, we use a transport decomposition to present processes that lead to convergent SPM transport, and review trapping mechanisms that lead to ETMs at the landward limit of the salt intrusion, in the freshwater zone, at topographic transitions, and by lateral processes within the cross section. We use model simulations of example estuaries to demonstrate the complex concurrence of ETM formation mechanisms. We also discuss how changes in SPM trapping mechanisms, often caused by direct human interference, can lead to the generation of hyperturbid estuaries.

Tidal and spatial variability of nitrous oxide (N2O) in Sado estuary (Portugal)

Science.gov (United States)

Gonçalves, Célia; Brogueira, Maria José; Nogueira, Marta

2015-12-01

The estimate of the nitrous oxide (N2O) fluxes is fundamental to assess its impact on global warming. The tidal and spatial variability of N2O and the air-sea fluxes in the Sado estuary in July/August 2007 are examined. Measurements of N2O and other relevant environmental parameters (temperature, salinity, dissolved oxygen and dissolved inorganic nitrogen - nitrate plus nitrite and ammonium) were recorded during two diurnal tidal cycles performed in the Bay and Marateca region and along the estuary during ebb, at spring tide. N2O presented tidal and spatial variability and varied spatially from 5.0 nmol L-1 in Marateca region to 12.5 nmol L-1 in Sado river input. Although the Sado river may constitute a considerable N2O source to the estuary, the respective chemical signal discharge was rapidly lost in the main body of the estuary due to the low river flow during the sampling period. N2O varied with tide similarly between 5.2 nmol L-1 (Marateca) and 10.0 nmol L-1 (Sado Bay), with the maximum value reached two hours after flooding period. The influence of N2O enriched upwelled seawater (˜10.0 nmol L-1) was well visible in the estuary mouth and apparently represented an important contribution of N2O in the main body of Sado estuary. Despite the high water column oxygen saturation in most of Sado estuary, nitrification did not seem a relevant process for N2O production, probably as the concentration of the substrate, NH4+, was not adequate for this process to occur. Most of the estuary functioned as a N2O source, and only Marateca zone has acted as N2O sink. The N2O emission from Sado estuary was estimated to be 3.7 Mg N-N2O yr-1 (FC96) (4.4 Mg N-N2O yr-1, FRC01). These results have implications for future sampling and scaling strategies for estimating greenhouse gases (GHGs) fluxes in tidal ecosystems.

Geochronological study of the Guanabara Bay (Rio de Janeiro State, Brazil) using 2'10 Pb dating technique and the constant rate of supply model

International Nuclear Information System (INIS)

Silva Braganca, Maura Julia Camara da; Oliveira Godoy, Jose Marcos de

1995-01-01

A geochronological study of the Guanabara Bay (RJ, Brazil) based on 210 Pb dating technique using the Constant Rate of Supply Model CRS is presented. A low energy gamma spectrometry ( 210 Pb for samples collected from Estrela and Sao Joao de Meriti rivers. Radiochemical method was applied to determine the amount of 210 Pb in samples from Guapimirim, Guaxindiba and Imbuacu rivers. Atomic absorption spectrometry with air-acetylene flame technique was used to determine the amount of copper in all the samples. The CRS model showed adequate in this estuarine system. (author). 19 refs., 5 figs., 6 tabs

Birds of Mahi River estuary, Gujarat, India

Directory of Open Access Journals (Sweden)

P.J. Pandya

2010-06-01

Full Text Available The Mahi river estuary is one of the major estuaries of Gujarat. This paper presents a comprehensive list of birds of the Mahi river estuary (nearly 50 km stretch and the adjacent banks/ravines and defines the avian diversity at three major estuarine gradations with a brief check of similarity and diversity within the three. The present observation is the outcome of a 3 year period from August 2006 to July 2009. A sum total of 118 species belonging to 42 families were reported and listed as on Upstream, Midstream, and Downstream of estuary. No significant difference was seen in the species richness at the three zones; a change in avian composition at upstream and downstream was notable.

Hydro-morphological modelling of small, wave-dominated estuaries

Science.gov (United States)

Slinger, Jill H.

2017-11-01

Small, intermittently open or closed estuaries are characteristic of the coasts of South Africa, Australia, California, Mexico and many other areas of the world. However, modelling attention has tended to focus on big estuaries that drain large catchments and serve a wide diversity of interests e.g. agriculture, urban settlement, recreation, commercial fishing. In this study, the development of a simple, parametric, system dynamics model to simulate the opening and closure of the mouths of small, wave-dominated estuaries is reported. In the model, the estuary is conceived as a basin with a specific water volume to water level relationship, connected to the sea by a channel of fixed width, but variable sill height. Changes in the form of the basin are not treated in the model, while the dynamics of the mouth channel are central to the model. The magnitude and direction of the flow through the mouth determines whether erosion or deposition of sediment occurs in the mouth channel, influencing the sill height. The model is implemented on the Great Brak Estuary in South Africa and simulations reveal that the raised low water levels in the estuary during spring tide relative to neap tide, are occasioned by the constriction of the tidal flow through the shallow mouth. Freshwater inflows to the estuary are shown to be significant in determining the behaviour of the inlet mouth, a factor often ignored in studies on tidal inlets. Further it is the balance between freshwater inflows and wave events that determines the opening or closure of the mouth of a particular estuary.

Trapping of sediment in tidal estuaries

NARCIS (Netherlands)

Chernetsky, A.

2012-01-01

An estuary is an ideal habitat for various aquatic species. At the same time, estuaries and adjacent rivers are used as fast navigation routes between the coastal and inland territories. The fast industrial development and the subsequent growth of cities and trade have led to large-scale

Frequent Questions about Estuary Data Mapper (EDM)

Science.gov (United States)

Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

Downloading and Installing Estuary Data Mapper (EDM)

Science.gov (United States)

Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

Plutonium speciation and isotope ratios in Yenisey and Ob river and Yenisey estuary

International Nuclear Information System (INIS)

Skipperud, L.; Oughton, DH.; Fifield, K.; Lind, O.C.; Salbu, B.; Brown, J.

2004-01-01

Plutonium isotope ratios are known to vary with reactor type, nuclear fuel-burn up time, neutron flux, and energy, and for fallout from nuclear detonations, weapon type and yield. Weapons-grade plutonium is characterized by a low content of the 240 Pu isotope, with 240 Pu/ 239 Pu isotope ratio less than 0.05. In contrast, both global weapons fallout and spent nuclear fuel from civil reactors have higher 240 Pu/ 239 Pu isotope ratios (civil nuclear power reactors have 240 Pu/ 239 Pu atom ratios of between about 0.2-1). Thus, different sources often exhibit characteristic plutonium isotope ratios and these ratios can be used to identify the origin of contamination, calculate inventories, or follow the migration of contaminated sediments and waters. Together with activity measurements and isotope ratios, knowledge of plutonium speciation in the Ob and Yenisey rivers and processes controlling its behaviour in estuarine systems is a prerequisite for predicting the transfer and subsequent environmental impact to Arctic Seas. With this in mind, the study had two objectives: first to determine whether discharges from nuclear installations in the river catchment areas are having any influence on Pu levels in the estuaries; and, second, to investigate the transfer and mobility of plutonium in the Yenisey river and estuary. Plutonium 240/239 ratios were determined using accelerator mass spectrometry (AMS). The data indicated a clear influence from a low 240 Pu: 239 Pu source in surface sediments collected from the Yenisey Estuary, whereas plutonium in the Ob Estuary sediments are dominated by global fallout. The results also show an increase in plutonium concentration and a decrease in isotope ratio going upstream from the estuary. Sequential extractions of sediments indicate that up 70% of the Pu in the Yenisey river is easily mobilized with weak oxidizing agents, which indicates that the Pu is organically bound, while the Pu is more strongly irreversible bound further out

Spatial variation, speciation and sedimentary records of mercury in the Guanabara Bay (Rio de Janeiro, Brazil)

Science.gov (United States)

Covelli, Stefano; Protopsalti, Ioanna; Acquavita, Alessandro; Sperle, Marcelo; Bonardi, Maurizio; Emili, Andrea

2012-03-01

As part of the "TAGUBAR" (TAngential GUanabara Bay Aeration Recovery) project, surface and long core sediments of the Guanabara Bay (Rio de Janeiro, Brazil) were investigated for mercury (Hg). The main, but not the only, input of Hg into the Bay's waters is known to be a Chlor-Alkali Plant (CAP) located in the Acarì-São João de Merití River system, on the northwestern side of the Bay. Mercury distribution in surface sediments (<0.1-3.22 mg kg-1, average 0.87±0.80, n=40) seems to be controlled by the organic component, along with sulfur rather than grain-size, where Hg concentrations are less than 1 mg kg-1. Conversely, where the metal contents are higher than 1 mg kg-1, accumulation in surface sediments is mostly related to the presence of nearby contamination sources, such as industrial and urban settlements in the western sector of the Bay. Although total Hg contents in surface sediments exceed the values suggested by the effects-based standard quality guidelines as potentially toxic for the benthic community, results from a sequential extraction procedure showed that the contribution of the more soluble, easily exchangeable and eventually bioavailable Hg phases was found almost negligible (<0.1%). Most of the metal is strongly bound to the mineral lattice of the sedimentary matrix and should therefore be considered almost immobilized. The reduction in Hg accumulation in bottom sediments, expected as a consequence of the adoption of contamination control policies (i.e. Hg-free technologies in the CAP and sewage treating facilities), has not been clearly observed in the core profiles. Current estimates of Hg accumulation rates at the core top range from approximately 1 to 18 mg m-2 yr-1. Pre-industrial bottom core samples indicate that the central and northeastern sectors of the Bay are strongly affected by Hg enrichment: concentrations exceed the estimated baseline concentration by up to 20 factors. A cumulative Hg inventory suggests that the metal content

Absorption and fluorescence characteristics of chromophoric dissolved organic matter in the Yangtze Estuary.

Science.gov (United States)

Sun, Qiyuan; Wang, Chao; Wang, Peifang; Hou, Jun; Ao, Yanhui

2014-03-01

The Yangtze Estuary is heavily influenced by coast-continent geochemical processes and anthropogenic activity; thus, the source and distribution of chromophoric dissolved organic matter (CDOM) in the estuary are strongly impacted by these processes. Here, a series of samples were collected from across the Yangtze Estuary to investigate the source and spatial dynamics of CDOM and its components throughout the system. Three indices (a(355), spectral slope, and fluorescence) were then calculated and interpreted. The results indicated that the distribution of CDOM was dominated by allochthonous input, conservative mixing, and phase transfer. The contribution of biogenic CDOM to total CDOM increased with salinity, and three individual CDOM components were identified upon fluorescence excitation emission matrix spectroscopy and parallel factor analysis of the water samples: C1, corresponding to humic substance-like CDOM, C2, corresponding to tryptophan-like CDOM, and C3, corresponding to tyrosine-like CDOM. C1 primarily originated from a terrestrial source, C2 had widespread origins, none of which played a dominant role, and C3 mainly originated from allochthonous input in the medium salinity area. Unexpectedly, no marine humic-like component was found in the surface water of the Yangtze Estuary, possibly because turbidity decreased the depth of sunlight penetration, limiting production of this component.

Impact of the river Liffey discharge on nutrient and chlorophyll concentrations in the Liffey estuary and Dublin Bay (Irish Sea)

Science.gov (United States)

O'Higgins, T. G.; Wilson, J. G.

2005-08-01

Temperature, salinity, nutrients (total oxidised nitrogen (TON), ammonium (NH 4) and orthophosphate (PO 4)) and chlorophyll a were monitored in the Liffey estuary and Dublin Bay from June 2000 to June 2003. Four groups of sites were defined comprising the upper estuary (Gp. I), the outer estuary (Gp. III) with a small set (Gp. II) of sites between Groups I and III heavily influenced by the sewage treatment works outflow, and the Bay proper (Gp. IV). Riverine inputs of TON and PO 4 were calculated at an average of 826 t N y -1 and 31 t P y -1, respectively, and were largely controlled by flow rate. The sewage treatment works were identified as a major source of PO 4 and NH 4 to the system. Mixing in the upper estuary of nutrient limited saline waters with hypernutrified river water regularly (i.e. annually) produced relatively high concentrations of chlorophyll a (>10 mg chl a m -3), and also sporadic blooms with extremely high chlorophyll a values (max. 121.6 mg chl a m -3). These latter phytoplankton blooms occurred in high salinity waters and were due to mixing of nutrient limited saline waters and nutrient rich river waters. The mean annual flux of phytoplankton carbon from the river Liffey was calculated at 23.5 t C y -1, of which half was accumulated or remineralised in the estuary and did not enter the Bay. In the Bay proper (Gp. IV) summer nutrient concentrations dropped below detection limits, and chlorophyll a concentrations followed the classic pattern with a spring bloom maximum of 5.5 mg chl a m -3. This pattern in nutrients and chlorophyll a came from the advection of waters into the Bay from an offshore source. Overall while there was considerable evidence for eutrophication in the estuary, the bay itself showed little biological response to nutrient loading.

Ecological implications of changes in polychaetes population in a shallow Danish estuary

DEFF Research Database (Denmark)

Delefosse, Matthieu

Burrowing polychaetes are typically the most numerous and active class among macrobenthic infauna in Danish estuaries. Their ecological role is well-recognized and has been often associated with their bioturbating activities. Construction and maintenance of galleries as well as ingestion and defe......Burrowing polychaetes are typically the most numerous and active class among macrobenthic infauna in Danish estuaries. Their ecological role is well-recognized and has been often associated with their bioturbating activities. Construction and maintenance of galleries as well as ingestion...... and defecation displace sediment particles. Ventilation of their burrow irrigates the sediment. These activities transform the environment for other species: from microbes to plants (MS5). Given the important relations between bioturbating polychaetes and their ecosystem, any significant changes in population...... of a key species may have consequent impact on the ecosystem. The introduction of non-native species is an important vector of change for the often species-poor benthic community of Danish estuaries. Non-native species may bring new functions but also interact with native fauna species. The work presented...

Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program.

Energy Technology Data Exchange (ETDEWEB)

Johnson, Gary E.; Diefenderfer, Heida L. (Pacific Northwest National Laboratory)

2008-02-20

The purpose of this document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program, hereafter called 'the Estuary Program'. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows: (1) Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. (2) Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. (3) Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. (4) Maintain the food web to benefit salmonid performance. (5) Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. The goal leads to three primary management questions pertaining to the main focus of the Estuary Program: estuary habitat conservation and restoration. (1) Are the estuary habitat actions achieving the expected biological and environmental performance targets? (2) Are the offsite habitat actions in the estuary improving juvenile salmonid performance and which actions are most effective at addressing the limiting factors preventing achievement of habitat, fish, or wildlife performance objectives? (3) What are the limiting factors or threats in the estuary/ocean preventing the achievement of desired habitat or fish performance objectives? Performance measures

Oil spill aftermath : temporal evaluation of hydrocarbon sources in Guanabara Bay, Brazil

International Nuclear Information System (INIS)

Meniconi, M.F.G.; Massone, C.G.; Scofield, A.L.; Junior, V.J.F.

2005-01-01

The sources of polycyclic aromatic hydrocarbons (PAH) in environmental ecosystems are both natural and anthropogenic. PAHs interact with different types of environmental compartments and are subject to processes that lead to geochemical fates such as physical-chemical transformation, biodegradation and photo-oxidation. This study examined the sources of PAHs in the estuarine sediment of Guanabara Bay, Brazil following an accidental oil spill from an oil refinery in January 2000. The main portion of the oil was carried by tidal currents and wind. It spread over the water and reached islands and shorelines at the north part of the bay. The objective of this study was to determine the likely sources of hydrocarbons in the bay where untreated municipal sewage and industrial wastes are also dumped. Sediment samples were collected using cores and dredges from the intertidal and subtidal regions of the bay, reflecting both affected and unaffected areas. This paper summarized the results of 16 EPA priority PAH and their alkylated homologues from 21 sediment samples collected in the bay 10 days after the oil spill, immediately after the clean up effort, and then 3 years later. The hydrocarbon source was determined using PAH ratios for the samples studied. The highest PAH concentration was observed in 2000 as a result of the petrogenic and pyrolytic contribution to the sediments. 38 refs., 3 tabs., 9 figs

Sedimentary fabrics of the macrotidal, mud-dominated, inner estuary to fluvio-tidal transition zone, Petitcodiac River estuary, New Brunswick, Canada

Science.gov (United States)

Shchepetkina, Alina; Gingras, Murray K.; Zonneveld, John-Paul; Pemberton, S. George

2016-03-01

The study provides a detailed description of mud-dominated sedimentary fabrics and their application for the rock record within the inner estuary to the fluvial zone of the Petitcodiac River estuary, New Brunswick, Canada. Sedimentological characteristics and facies distributions of the clay- and silt-rich deposits are reported. The inner estuary is characterized by thick accumulations of interbedded silt and silty clay on intertidal banks that flank the tidally influenced channel. The most common sedimentary structures observed are parallel and wavy lamination, small-scale soft-sediment deformation with microfaults, and clay and silt current ripples. The tidal channel contains sandy silt and clayey silt with planar lamination, massive and convolute bedding. The fluvio-tidal transition zone is represented by interbedded trough cross-stratified sand and gravel beds with planar laminated to massive silty mud. The riverine, non-tidal reach of the estuary is characterized by massive, planar tabular and trough cross-stratified gravel-bed deposits. The absence of bioturbation within the inner estuary to the fluvio-tidal transition zone can be explained by the following factors: low water salinities (0-5 ppt), amplified tide and current speeds, and high concentrations of flocculated material in the water body. Notably, downstream in the middle and outer estuary, bioturbation is seasonally pervasive: in those locales the sedimentary conditions are similar, but salinity is higher. In this study, the sedimentological (i.e., grain size, bedding characters, sedimentary structures) differences between the tidal estuary and the fluvial setting are substantial, and those changes occur over only a few hundred meters. This suggests that the widely used concept of an extensive fluvio-tidal transition zone and its depositional character may not be a geographically significant component of fluvial or estuary deposits, which can go unnoticed in the study of the ancient rocks.

Radioactive Cs in the estuary sediments near Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Yamasaki, Shinya; Imoto, Junpei; Furuki, Genki; Ochiai, Asumi; Ohnuki, Toshihiko; Sueki, Keisuke; Nanba, Kenji; Ewing, Rodney C.; Utsunomiya, Satoshi

2016-01-01

The migration and dispersion of radioactive Cs (mainly "1"3"4Cs and "1"3"7Cs) are of critical concern in the area surrounding the Fukushima Daiichi Nuclear Power Plant (FDNPP). Considerable uncertainty remains in understanding the properties and dynamics of radioactive Cs transport by surface water, particularly during rainfall-induced flood events to the ocean. Physical and chemical properties of unique estuary sediments, collected from the Kuma River, 4.0 km south of the FDNPP, were quantified in this study. These were deposited after storm events and now occur as dried platy sediments on beach sand. The platy sediments exhibit median particle sizes ranging from 28 to 32 μm. There is increasing radioactivity towards the bottom of the layers deposited; approximately 28 and 38 Bq g"−"1 in the upper and lower layers, respectively. The difference in the radioactivity is attributed to a larger number of particles associated with radioactive Cs in the lower part of the section, suggesting that radioactive Cs in the suspended soils transported by surface water has decreased over time. Sequential chemical extractions showed that ~ 90% of "1"3"7Cs was strongly bound to the residual fraction in the estuary samples, whereas 60 ~ 80% of "1"3"7Cs was bound to clays in the six paddy soils. This high concentration in the residual fraction facilitates ease of transport of clay and silt size particles through the river system. Estuary sediments consist of particles < 100 μm. Radioactive Cs desorption experiments using the estuary samples in artificial seawater revealed that 3.4 ± 0.6% of "1"3"7Cs was desorbed within 8 h. More than 96% of "1"3"7Cs remained strongly bound to clays. Hence, particle size is a key factor that determines the travel time and distance during the dispersion of "1"3"7Cs in the ocean. - Highlights: • Cs-137 of estuary sediment impacted by the FDNPP was measured. • Physical and chemical properties were measured also. • Increasing radioactivity was

Radioactive Cs in the estuary sediments near Fukushima Daiichi Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Yamasaki, Shinya, E-mail: s-yamasaki@ied.tsukuba.ac.jp [Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Imoto, Junpei; Furuki, Genki; Ochiai, Asumi [Department of Chemistry, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Ohnuki, Toshihiko [Advanced Science Research Center, Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Sueki, Keisuke [Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Nanba, Kenji [Department of Environmental Management, Faculty of Symbiotic System Science, Fukushima University, Kanayagawa 1, Fukushima, 960-1296 (Japan); Ewing, Rodney C. [Department of Geological Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA 94305-2115 (United States); Utsunomiya, Satoshi [Department of Chemistry, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

2016-05-01

The migration and dispersion of radioactive Cs (mainly {sup 134}Cs and {sup 137}Cs) are of critical concern in the area surrounding the Fukushima Daiichi Nuclear Power Plant (FDNPP). Considerable uncertainty remains in understanding the properties and dynamics of radioactive Cs transport by surface water, particularly during rainfall-induced flood events to the ocean. Physical and chemical properties of unique estuary sediments, collected from the Kuma River, 4.0 km south of the FDNPP, were quantified in this study. These were deposited after storm events and now occur as dried platy sediments on beach sand. The platy sediments exhibit median particle sizes ranging from 28 to 32 μm. There is increasing radioactivity towards the bottom of the layers deposited; approximately 28 and 38 Bq g{sup −1} in the upper and lower layers, respectively. The difference in the radioactivity is attributed to a larger number of particles associated with radioactive Cs in the lower part of the section, suggesting that radioactive Cs in the suspended soils transported by surface water has decreased over time. Sequential chemical extractions showed that ~ 90% of {sup 137}Cs was strongly bound to the residual fraction in the estuary samples, whereas 60 ~ 80% of {sup 137}Cs was bound to clays in the six paddy soils. This high concentration in the residual fraction facilitates ease of transport of clay and silt size particles through the river system. Estuary sediments consist of particles < 100 μm. Radioactive Cs desorption experiments using the estuary samples in artificial seawater revealed that 3.4 ± 0.6% of {sup 137}Cs was desorbed within 8 h. More than 96% of {sup 137}Cs remained strongly bound to clays. Hence, particle size is a key factor that determines the travel time and distance during the dispersion of {sup 137}Cs in the ocean. - Highlights: • Cs-137 of estuary sediment impacted by the FDNPP was measured. • Physical and chemical properties were measured also. �

Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

Directory of Open Access Journals (Sweden)

Katherine A Dafforn

Full Text Available Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching. Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

The Mntafufu and Mzamba River estuaries

African Journals Online (AJOL)

1989-03-14

Mar 14, 1989 ... A survey of the fish fauna of Transkei estuaries. Part Four: The Mntafufu and Mzamba River estuaries. E.E. Plumstead • and J.F. Prinsloo. Department of Zoology, University of Transkei, Private Bag X1, Unitra, Umtata, Republic of Transkei. H.J. Schoonbee. Department of Zoology, Rand Afrikaans University, ...

Silicon dynamics in the Oder estuary, Baltic Sea

Science.gov (United States)

Pastuszak, Marianna; Conley, Daniel J.; Humborg, Christoph; Witek, Zbigniew; Sitek, Stanisław

2008-10-01

Studies on dissolved silicate (DSi) and biogenic silica (BSi) dynamics were carried out in the Oder estuary, Baltic Sea in 2000-2005. The Oder estuary proved to be an important component of the Oder River-Baltic Sea continuum where very intensive seasonal DSi uptake during spring and autumn, but also BSi regeneration during summer take place. Owing to the regeneration process annual DSi patterns in the river and the estuary distinctly differed; the annual patterns of DSi in the estuary showed two maxima and two minima in contrast to one maximum- and one minimum-pattern in the Oder River. DSi concentrations in the river and in the estuary were highest in winter (200-250 μmol dm - 3 ) and lowest (often less than 1 μmol dm - 3 ) in spring, concomitant with diatom growth; such low values are known to be limiting for new diatom growth. Secondary DSi summer peaks at the estuary exit exceeded 100 μmol dm - 3 , and these maxima were followed by autumn minima coinciding with the autumn diatom bloom. Seasonal peaks in BSi concentrations (ca. 100 μmol dm - 3 ) occurred during the spring diatom bloom in the Oder River. Mass balance calculations of DSi and BSi showed that DSi + BSi import to the estuary over a two year period was 103.2 kt and that can be compared with the DSi export of 98.5 kt. The difference between these numbers gives room for ca. 2.5 kt BSi to be annually exported to the Baltic Sea. Sediment cores studies point to BSi annual accumulation on the level of 2.5 kt BSi. BSi import to the estuary is on the level of ca. 10.5 kt, thus ca. 5 kt of BSi is annually converted into the DSi, increasing the pool of DSi that leaves the system. BSi concentrations being ca. 2 times higher at the estuary entrance than at its exit remain in a good agreement with the DSi and BSi budgeting presented in the paper.

Local Estuary Programs

Science.gov (United States)

This page provides information about Local Individual Estuary Programs including links to their NEP homepages, social media, Comprehensive Conservation and Management Plans, and state of the bay reports.

Milwaukee Estuary AOC

Science.gov (United States)

The rivers in the Milwaukee estuary in Wisconsin drain into Lake Michigan. Wastewater treatment plants and combined sewer overflows contribute pollution which affects fish and wildlife and recreation.

Effects of heavy metal contamination on the macrobenthic fauna in estuaries: The case of the Seine estuary

International Nuclear Information System (INIS)

Dauvin, Jean-Claude

2008-01-01

Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites

Delaware Estuary situation reports. Emergency response: How do emergency management officials address disasters in the Delaware Estuary

International Nuclear Information System (INIS)

Sylves, R.T.

1991-01-01

From hurricanes and other natural threats to oil spills and other manmade emergencies, the Delaware Estuary has experienced a variety of disasters over the years. The toll that these events take on the estuary and those who live on its shores depends largely upon the degree of emergency preparedness, speed of response, and effectiveness of recovery operations. In Emergency Response: How Do Emergency Management Officials Address Disasters in the Delaware Estuary, the latest addition to its Delaware Estuary Situation Report series, the University of Delaware Sea Grant College Program defines emergency management; examines the roles that the Coast Guard, Army Corps of Engineers, and Environmental Protection Agency play in an emergency; and reviews how each of these federal agencies operated during an actual disaster--the 1985 Grand Eagle oil spill. The report was written by Dr. Richard T. Sylves, a professor of political science at the University of Delaware. Sylves has been studying emergency management for the past 15 years, with special emphasis on oil spill preparedness and response in the Mid-Atlantic Region. The Delaware Estuary Situation Report is 12 pages long and contains maps and photographs, as well as a detailed account of response and recovery operations undertaken during the Grand Eagle oil spill. A comparison of the 1985 Grand Eagle spill and the 1989 Presidente Rivera spill also is included

Improving navigability on the Kromme River Estuary: A choice ...

African Journals Online (AJOL)

Navigation of estuaries is a vitally important aspect of boating recreation in South Africa and elsewhere. This paper uses a choice experiment to estimate recreation values of the Kromme River Estuary, a popular estuary along South Africa's east coast. This valuation methodology allows for the identification of preferred ...

Environmental Flow for Sungai Johor Estuary

Science.gov (United States)

Adilah, A. Kadir; Zulkifli, Yusop; Zainura, Z. Noor; Bakhiah, Baharim N.

2018-03-01

Sungai Johor estuary is a vital water body in the south of Johor and greatly affects the water quality in the Johor Straits. In the development of the hydrodynamic and water quality models for Sungai Johor estuary, the Environmental Fluid Dynamics Code (EFDC) model was selected. In this application, the EFDC hydrodynamic model was configured to simulate time varying surface elevation, velocity, salinity, and water temperature. The EFDC water quality model was configured to simulate dissolved oxygen (DO), dissolved organic carbon (DOC), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), nitrate nitrogen (NO3-N), phosphate (PO4), and Chlorophyll a. The hydrodynamic and water quality model calibration was performed utilizing a set of site specific data acquired in January 2008. The simulated water temperature, salinity and DO showed good and fairly good agreement with observations. The calculated correlation coefficients between computed and observed temperature and salinity were lower compared with the water level. Sensitivity analysis was performed on hydrodynamic and water quality models input parameters to quantify their impact on modeling results such as water surface elevation, salinity and dissolved oxygen concentration. It is anticipated and recommended that the development of this model be continued to synthesize additional field data into the modeling process.

Functional diversity of fish in tropical estuaries: A traits-based approach of communities in Pernambuco, Brazil

Science.gov (United States)

Silva-Júnior, C. A. B.; Mérigot, B.; Lucena-Frédou, F.; Ferreira, B. P.; Coxey, M. S.; Rezende, S. M.; Frédou, T.

2017-11-01

Environmental changes and human activities may have strong impacts on biodiversity and ecosystem functioning. While biodiversity is traditionally based on species richness and composition, there is a growing concern to take into account functional diversity to assess and manage species communities. In spite of their economic importance, functional diversity quantified by a traits-based approach is still poorly documented in tropical estuaries. In this study, the functional diversity of fishes was investigated within four estuaries in Pernambuco state, northeast of Brazil. These areas are subject to different levels of human impact (e.g. mangrove deforestation, shrimp farming, fishing etc.) and environmental conditions. Fishes were collected during 34 scientific surveys. A total of 122 species were identified and 12 functional traits were quantified describing two main functions: food acquisition and locomotion. Fish abundance and functional dissimilarities data were combined into a multivariate analysis, the Double Principal Coordinate Analysis, to identify the functional typology of fish assemblages according to the estuary. Results showed that Itapissuma, the largest estuary with a wider mangrove forest area, differs from the other three estuaries, showing higher mean values per samples of species richness S and quadratic entropy Q. Similarly, it presented a different functional typology (the first two axes of the DPCoA account for 68.7% of total inertia, while those of a traditional PCA based solely on species abundances provided only 17.4%). Conversely, Suape, Sirinhaém, and to a lower extent Rio Formoso, showed more similarity in their diversity. This result was attributed to their predominantly marine influenced hydrological features, and similar levels of species abundances and in morphological traits. Overall, this study, combining diversity indices and a recent multivariate analysis to access species contribution to functional typology, allows to deepen

FLORA OF MOLOCHNYI ESTUARY COASTS

Directory of Open Access Journals (Sweden)

Kolomiychuk V.P.

2013-09-01

Full Text Available Present-day characteristic of the coastal flora of Molochnyi eastury is given, that is one of the largest estuaries in Ukraine, the shores and waters of which in 2009 became a part of the Pryazov’ya National Nature Park. The analysis of the main parameters of the flora is made. Rare component of the estuary coastal flora is characterized, further steps to conserve the nature of Pryazov’ya are proposed.

Influence of estuaries on shelf foraminiferal species

Digital Repository Service at National Institute of Oceanography (India)

Nigam, R.

Dabhol-bhatkal stretch of the west coast of India is marked by a number of estuaries. Cavarotalia annectens is selected to monitor the influence of these estuaries on the inner shelf foraminiferal fauna. The percentage distribution of this species...

Juvenile salmon usage of the Skeena River estuary.

Science.gov (United States)

Carr-Harris, Charmaine; Gottesfeld, Allen S; Moore, Jonathan W

2015-01-01

Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that

Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program

Energy Technology Data Exchange (ETDEWEB)

Johnson, Gary E.; Diefenderfer, Heida L.; Ebberts, Blaine D.; Tortorici, Cathy; Yerxa, Tracey; Leary, J.; Skalski, John R.

2008-02-05

The purpose ofthis document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision-making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows. 1. Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. 2. Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. 3. Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. 4. Maintain the food web to benefit salmonid performance. 5. Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. In conclusion, the estuary RME effort is designed to meet the research and monitoring needs of the estuary Program using an adaptive management process. Estuary RME's success and usefulness will depend on the actual conduct of adaptive management, as embodied in the objectives, implrementation, data, reporting, and synthesis, evaluation, and decision-making described herein.

Distribution and assessment of sediment toxicity in Tamaki Estuary, Auckland, New Zealand

Science.gov (United States)

Abrahim, G. M. S.; Parker, R. J.; Nichol, S. L.

2007-07-01

Heavy metal levels in surface sediments from Tamaki Estuary demonstrate significant up estuary increases in Cu, Pb, Zn, Cd and mud concentrations. Increased metal levels towards the head of the estuary are linked to local catchment sources reflecting the historical development, industrialisation and urbanisation of catchment areas surrounding the upper estuary. The relatively narrow constriction in the middle estuary (Panmure area), makes it susceptible to accumulation of upper estuary pollutants, since the constriction reduces circulation and extends the time required for fine waterborne sediments in the upper estuary to exchange with fresh coastal water. As a result fine fraction sediments trapped in the upper estuary facilitate capture and retention of pollutants at the head of the estuary. The increase in sandy mud poor sediments towards the mouth of the estuary is associated with generally low metal concentrations. The estuary’s geomorphic shape with a mid estuary constriction, sediment texture and mineralogy and catchment history are significant factors in understanding the overall spatial distribution of contaminants in the estuary. Bulk concentration values for Cu, Pb, Zn, and Cd in all the studied surface samples occur below ANZECC ISQG-H toxicity values. Cd and Cu concentrations are also below the ISQG-L toxicity levels for these elements. However, Pb and Zn concentrations do exceed the ISQG-L values in some of the surface bulk samples in the upper estuary proximal to long established sources of catchment pollution.

Succession in rocky intertidal benthic communities in areas with different pollution levels at Guanabara Bay (RJ-Brazil

Directory of Open Access Journals (Sweden)

André Breves-Ramos

2005-11-01

Full Text Available The aim of this study was to describe and compare the succession of intertidal benthic communities in two areas at Guanabara Bay, RJ, Brazil: Urca, an area submitted to moderated organic pollution and Catalão, an extremely polluted area. Three transects in each area were scraped one month before the beginning of this study in order to evaluate the recruitment (recruitment-treatments. Three other transects were monitored without manipulation (monitoring treatments. Species composition and relative abundance were evaluated monthly between September and December, 2000. A total of 26 species was found at Urca and 13 at Catalão. The percent cover of the most abundant organisms was not similar between treatments at Urca after four months, while in Catalão, the similarity was 72% in the second month. The faster community development and recovery at the most polluted area was probably related to the existence of simple and resilient communities in more impacted areas.O objetivo deste estudo foi descrever e comparar a sucessão das comunidades bentônicas da região entre-marés, em duas áreas na Baía de Guanabara, RJ, Brasil: Urca, uma área sujeita a moderado nível de poluição orgânica, e Catalão, uma área extremamente poluída. Em cada área, três transectos verticais foram raspados um mês antes do início do estudo, para se avaliar o recrutamento dos organismos (tratamento Recrutamento, enquanto três outros transectos foram monitorados sem manipulação (tratamento Monitoramento. A porcentagem de cobertura dos organismos foi avaliada pelo método de interseção. A composição específica e a abundância relativa dos organismos foram avaliadas mensalmente entre Setembro e Dezembro de 2000. Um total de 26 espécies foi encontrado na Urca, enquanto 13 foram encontradas no Catalão. Após quatro meses, a composição específica observada no recrutamento na Urca foi muito similar (76% a observada no monitoramento. No Catalão, três meses

Metagenomic profiles of antibiotic resistance genes (ARGs) between human impacted estuary and deep ocean sediments.

Science.gov (United States)

Chen, Baowei; Yang, Ying; Liang, Ximei; Yu, Ke; Zhang, Tong; Li, Xiangdong

2013-11-19

Knowledge of the origins and dissemination of antibiotic resistance genes (ARGs) is essential for understanding modern resistomes in the environment. The mechanisms of the dissemination of ARGs can be revealed through comparative studies on the metagenomic profiling of ARGs between relatively pristine and human-impacted environments. The deep ocean bed of the South China Sea (SCS) is considered to be largely devoid of anthropogenic impacts, while the Pearl River Estuary (PRE) in south China has been highly impacted by intensive human activities. Commonly used antibiotics (sulfamethazine, norfloxacin, ofloxacin, tetracycline, and erythromycin) have been detected through chemical analysis in the PRE sediments, but not in the SCS sediments. In the relatively pristine SCS sediments, the most prevalent and abundant ARGs are those related to resistance to macrolides and polypeptides, with efflux pumps as the predominant mechanism. In the contaminated PRE sediments, the typical ARG profiles suggest a prevailing resistance to antibiotics commonly used in human health and animal farming (including sulfonamides, fluoroquinolones, and aminoglycosides), and higher diversity in both genotype and resistance mechanism than those in the SCS. In particular, antibiotic inactivation significantly contributed to the resistance to aminoglycosides, β-lactams, and macrolides observed in the PRE sediments. There was a significant correlation in the levels of abundance of ARGs and those of mobile genetic elements (including integrons and plasmids), which serve as carriers in the dissemination of ARGs in the aquatic environment. The metagenomic results from the current study support the view that ARGs naturally originate in pristine environments, while human activities accelerate the dissemination of ARGs so that microbes would be able to tolerate selective environmental stress in response to anthropogenic impacts.

Estuaries of the northeastern United States: Habitat and land use signatures

Science.gov (United States)

Roman, C.T.; Jaworski, N.; Short, F.T.; Findlay, S.; Warren, R.S.

2000-01-01

Geographic signatures are physical, chemical, biotic, and human-induced characteristics or processes that help define similar or unique features of estuaries along latitudinal or geographic gradients. Geomorphologically, estuaries of the northeastern U.S., from the Hudson River estuary and northward along the Gulf of Maine shoreline, are highly diverse because of a complex bedrock geology and glacial history. Back-barrier estuaries and lagoons occur within the northeast region, but the dominant type is the drowned-river valley, often with rocky shores. Tidal range and mean depth of northeast estuaries are generally greater when compared to estuaries of the more southern U.S. Atlantic coast and Gulf of Mexico. Because of small estuarine drainage basins, low riverine flows, a bedrock substrate, and dense forest cover, sediment loads in northeast estuaries are generally quite low and water clarity is high. Tidal marshes, seagrass meadows, intertidal mudflats, and rocky shores represent major habitat types that fringe northeast estuaries, supporting commercially-important fauna, forage nekton and benthos, and coastal bird communities, while also serving as links between deeper estuarine waters and habitats through detritus-based pathways. Regarding land use and water quality trends, portions of the northeast have a history of over a century of intense urbanization as reflected in increased total nitrogen and total phosphorus loadings to estuaries, with wastewater treatment facilities and atmospheric deposition being major sources. Agricultural inputs are relatively minor throughout the northeast, with relative importance increasing for coastal plain estuaries. Identifying geographic signatures provides an objective means for comparing the structure function, and processes of estuaries along latitudinal gradients.

An assessment of natural radionuclides in water of Langat River estuary, Selangor

Energy Technology Data Exchange (ETDEWEB)

Hamzah, Zaini, E-mail: tengkuliana88@gmail.com; Rosli, Tengku Nurliana Tuan Mohd, E-mail: tengkuliana88@gmail.com; Saat, Ahmad, E-mail: tengkuliana88@gmail.com; Wood, Ab. Khalik, E-mail: tengkuliana88@gmail.com [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

2014-02-12

An estuary is an area that has a free connection with the open sea and it is a dynamic semi-enclosed coastal bodies. Ex-mining, aquaculture and industrial areas in Selangor are the sources of pollutants discharged into the estuary water. Radionuclides are considered as pollutants to the estuary water. Gamma radiations emitted by natural radionuclides through their decaying process may give impact to human. The radiological effect of natural radionuclides which are {sup 226}Ra, {sup 228}Ra, {sup 40}K, {sup 238}U and {sup 232}Th, were explored by determining the respective activity concentrations in filtered water along the Langat estuary, Selangor. Meanwhile, in- situ water quality parameters such as temperature, dissolve oxygen (DO), salinity, total suspended solid (TSS), pH and turbidity were measured by using YSI portable multi probes meter. The activity concentration of {sup 226}Ra, {sup 228}Ra and {sup 40}K were determined by using gamma-ray spectrometry with high-purity germanium (HPGe) detector. The activity concentrations of {sup 226}Ra, {sup 228}Ra and {sup 40}K in samples are in the range of 0.17 - 0.67 Bq/L, 0.16 - 0.97 Bq/L and 1.22 - 5.57 Bq/L respectively. On the other hand, the concentrations of uranium-238 and thorium-232 were determined by using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The thorium concentrations are between 0.17 ppm to 0.28 ppm and uranium concentrations were 0.25 ppm to 0.31 ppm. The results show activity concentrations of radionuclides are slightly high near the river estuary. The Radium Equivalent, Absorbed Dose Rate, External Hazard Index, and Annual Effective Dose of {sup 226}Ra, {sup 228}Ra and {sup 40}K are also studied.

Deschutes estuary feasibility study: hydrodynamics and sediment transport modeling

Science.gov (United States)

George, Douglas A.; Gelfenbaum, Guy; Lesser, Giles; Stevens, Andrew W.

2006-01-01

Continual sediment accumulation in Capitol Lake since the damming of the Deschutes River in 1951 has altered the initial morphology of the basin. As part of the Deschutes River Estuary Feasibility Study (DEFS), the United States Geological Survey (USGS) was tasked to model how tidal and storm processes will influence the river, lake and lower Budd Inlet should estuary restoration occur. Understanding these mechanisms will assist in developing a scientifically sound assessment on the feasibility of restoring the estuary. The goals of the DEFS are as follows. - Increase understanding of the estuary alternative to the same level as managing the lake environment.

Vulnerabilidade socioambiental dos pescadores e catadores de caranguejo da Baía de Guanabara: o trabalho e a saúde em um contexto de injustiça ambiental

OpenAIRE

Márcia Ferreira Mendes Rosa

2012-01-01

O estudo tem como objetivo compreender as alterações socioambientais e econômicas que exercem grande pressão no ecossistema e que atuam diretamente na vida, trabalho e saúde dos pescadores artesanais e dessa forma promover a discussão sobre a possibilidade do fim dessa atividade artesanal na Baía de Guanabara em um contexto de vulnerabilidade e injustiça ambiental. A atividade pesqueira artesanal desenvolvida durante décadas está ameaçada de acabar principalmente por conta da degradação do am...

ESTUDO GEOAMBIENTAL DAS CONCENTRAÇÕES DE HIDROCARBONETOS DE PETRÓLEO (POLICÍCLICOS AROMÁTICOS – HPAs) AO LONGO DO RIO ESTRELA, BAÍA DE GUANABARA – RJ

OpenAIRE

Carlos Marclei Arruda Rangel; José Antônio Baptista Neto; Estefan Monteiro da Fonseca

2013-01-01

DOI 10.12957/tamoios.2012.5083RESUMO Neste estudo, análises geoquímicas de dez amostras de sedimentos coletados ao longo do sistema fluvial do Rio Estrela, localizado ao norte da Baía de Guanabara, evidenciam a presença de impactos antropogênicos nesta área. As concentrações de hidrocarbonetos policíclicos aromáticos (HPAs) obtidas mostraram-se ligeiramente elevadas, quando comparadas com valores encontrados em ambientes naturais. Os HPAs foram analisados nos sedimentos ao longo da bacia do R...

Effectiveness of remediation of metal-contaminated mangrove sediments (Sydney estuary, Australia).

Science.gov (United States)

Birch, Gavin; Nath, Bibhash; Chaudhuri, Punarbasu

2015-04-01

Industrial activities and urbanization have had a major consequence for estuarine ecosystem health and water quality globally. Likewise, Sydney estuary has been significantly impacted by widespread, poor industrial practices in the past, and remediation of legacy contaminants have been undertaken in limited parts of this waterway. The objective of the present investigation was to determine the effectiveness of remediation of a former Pb-contaminated industrial site in Homebush Bay on Sydney estuary (Australia) through sampling of inter-tidal sediments and mangrove (Avicennia marina) tissue (fine nutritive roots, pneumatophores, and leaves). Results indicate that since remediation 6 years previously, Pb and other metals (Cu, Ni and Zn) in surficial sediment have increased to concentrations that approach pre-remediation levels and that they were considerably higher than pre-settlement levels (3-30 times), as well as at the reference site. Most metals were compartmentalized in fine nutritive roots with bio-concentration factors greater than unity, while tissues of pneumatophores and leaves contained low metal concentrations. Lead concentrations in fine nutritive root, pneumatophore, and leaf tissue of mangroves from the remediated site were similar to trees in un-remediated sites of the estuary and were substantially higher than plants at the reference site. The situation for Zn in fine nutritive root tissue was similar. The source of the metals was either surface/subsurface water from the catchment or more likely remobilized contaminated sediment from un-remediated parts of Homebush Bay. Results of this study demonstrate the problems facing management in attempting to reduce contamination in small parts of a large impacted area to concentrations below local base level.

Physicochemical and biological cycles in a tide dominated, nitrogen-polluted temperate estuary

OpenAIRE

Wafar, M.V.M.; Le Corre, P.; Birrien, J.L.

1988-01-01

Spatio-temporal variations in the physicochemical and biological parameters in the Morlaix estuary on the Brittany coast of France were studied. Hydrographically, the estuary can be classified into 3 segments: the upper estuary where stratification always persists, the lower estuary where vertical homogeneity is permanent, and a middle estuary where there is a regular oscillation of stratification and homogeneity during every tidal cycle, stratification being associated with slack waters and ...

Benthic Foraminifera and Bacterial Activity as a Proxy for Environmental Characterization in Potengi Estuary, Rio Grande do Norte, Brazil

Directory of Open Access Journals (Sweden)

Frederico S. da Silva

2010-01-01

Full Text Available The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development.

Wind Wave Behavior in Fetch and Depth Limited Estuaries

Science.gov (United States)

Karimpour, Arash; Chen, Qin; Twilley, Robert R.

2017-01-01

Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design.

Benthic macrofaunal structure and secondary production in tropical estuaries on the Eastern Marine Ecoregion of Brazil.

Science.gov (United States)

Bissoli, Lorena B; Bernardino, Angelo F

2018-01-01

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.

Greenhouse gas (N2O emission from Portuguese estuaries

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Célia Gonçalves

2014-07-01

Tagus, Minho and Lima estuaries are source of N2O to the atmosphere. Particularly, in Lima estuary anthropogenic N input seems to play an important role on N2O emission. However, in a global perspective N2O attained emissions represent a reduced fraction (2O yr-1, Barnes and Upstill-Goddard, 2011. Values are comparable with those registered in some Portuguese estuaries and other European less eutrophic estuaries. However, it is known that higher N2O emissions in estuaries may occur during winter and spring (Sun et al., 2014. Thus, these systems may represent on an annual basis a larger source of N2O, which can only be clarified in future studies. Only a full comprehension of the global estuarine nitrogen cycle will provide an efficient basis of scientific knowledge for sustainably management of such ecosystems and ultimately reduce N2O emissions.

Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators

International Nuclear Information System (INIS)

Valdez Domingos, F.X.; Azevedo, M.; Silva, M.D.; Randi, M.A.F.; Freire, C.A.; Silva de Assis, H.C.; Oliveira Ribeiro, C.A.

2007-01-01

Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 deg. S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamaraca oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended

Bar dynamics and channel junctions in scale-experiments of estuaries

Science.gov (United States)

Leuven, J.; Braat, L.; van Dijk, W. M.; Haas, T. D.; Kleinhans, M. G.

2017-12-01

The evolution of channels and bars in estuaries has high socio-economic relevance, with strong implications for navigation, dredging and ecology. However, the spatial and temporal evolution of channels and bars in estuaries is poorly understood. Here, we study feedbacks of bar morphodynamics on widening and narrowing of estuaries. Therefore, we conducted an experiment in a 20 m long and 3 m wide tilting flume (the 'Metronome'), in which we monitored the evolution of a self-formed estuary that developed from an intial straight channel into an irregular planform with multiple channels, braided bars and a meandering ebb channel. At locations where the estuary width is confined, major channel junctions occur, while the zones between the junctions are characterised by high braiding indices, periodically migrating channels and a relatively large estuary width. The junction locations were forced by the in- and outflow locations on the sides of the ebb-tidal delta and at the location where the channel pattern transitions from multiple channels into a single channel. In the middle of the estuary, self-confinement occurred by sedimentation on the sides of the estuary, which caused another major junction. The channel orientation at the junctions steers the morphodynamics of channels and bars immediately landward and seaward, because the orientation of inflow from the ebb-tidal delta and landward river perpetually varies. In natural systems major junction locations are mostly forced by inherited geology or human engineering. However, this study concludes that even without external forcing, the estuary planform will not converge to an ideal shape but will self-confine at major junctions and widens in the adjacent zones, resulting in an irregular planform shape.

Impact of urban effluents on summer hypoxia in the highly turbid Gironde Estuary, applying a 3D model coupling hydrodynamics, sediment transport and biogeochemical processes

Science.gov (United States)

Lajaunie-Salla, Katixa; Wild-Allen, Karen; Sottolichio, Aldo; Thouvenin, Bénédicte; Litrico, Xavier; Abril, Gwenaël

2017-10-01

Estuaries are increasingly degraded due to coastal urban development and are prone to hypoxia problems. The macro-tidal Gironde Estuary is characterized by a highly concentrated turbidity maximum zone (TMZ). Field observations show that hypoxia occurs in summer in the TMZ at low river flow and a few days after the spring tide peak. In situ data highlight lower dissolved oxygen (DO) concentrations around the city of Bordeaux, located in the upper estuary. Interactions between multiple factors limit the understanding of the processes controlling the dynamics of hypoxia. A 3D biogeochemical model was developed, coupled with hydrodynamics and a sediment transport model, to assess the contribution of the TMZ and the impact of urban effluents through wastewater treatment plants (WWTPs) and sewage overflows (SOs) on hypoxia. Our model describes the transport of solutes and suspended material and the biogeochemical mechanisms impacting oxygen: primary production, degradation of all organic matter (i.e. including phytoplankton respiration, degradation of river and urban watershed matter), nitrification and gas exchange. The composition and the degradation rates of each variable were characterized by in situ measurements and experimental data from the study area. The DO model was validated against observations in Bordeaux City. The simulated DO concentrations show good agreement with field observations and satisfactorily reproduce the seasonal and neap-spring time scale variations around the city of Bordeaux. Simulations show a spatial and temporal correlation between the formation of summer hypoxia and the location of the TMZ, with minimum DO centered in the vicinity of Bordeaux. To understand the contribution of the urban watershed forcing, different simulations with the presence or absence of urban effluents were compared. Our results show that in summer, a reduction of POC from SO would increase the DO minimum in the vicinity of Bordeaux by 3% of saturation. Omitting

Riverbed Micromorphology of the Yangtze River Estuary, China

Directory of Open Access Journals (Sweden)

Shuaihu Wu

2016-05-01

Full Text Available Dunes are present in nearly all fluvial channels and are vital in understanding sediment transport, deposition, and flow conditions during floods of rivers and estuaries. This information is pertinent for helping developing management practices to reduce risks in river transportation and engineering. Although a few recent studies have investigated the micromorphology of a portion of the Yangtze River estuary in China, our understanding of dune development in this large estuary is incomplete. It is also poorly understood how the development and characteristics of these dunes have been associated with human activities in the upper reach of the Yangtze River and two large-scale engineering projects in the estuarine zone. This study analyzed the feature in micromorphology of the entire Yangtze River estuary bed over the past three years and assessed the morphological response of the dunes to recent human activities. In 2012, 2014, and 2015, multi-beam bathymetric measurements were conducted on the channel surface of the Yangtze River estuary. The images were analyzed to characterize the subaqueous dunes and detect their changes over time. Bottom sediment samples were collected for grain size analysis to assess the physical properties of the dunes. We found that dunes in the Yangtze River estuary can be classified in four major classes: very large dunes, large dunes, medium dunes, and small dunes. Large dunes were predominant, amounting to 51.5%. There was a large area of dunes developed in the middle and upper reaches of the Yangtze River estuary and in the Hengsha Passage. A small area of dunes was observed for the first time in the turbidity maximum zone of the Yangtze River estuary. These dunes varied from 0.12 to 3.12 m in height with a wide range of wavelength from 2.83 to 127.89 m, yielding a range in height to wavelength of 0.003–0.136. Sharp leeside slope angles suggest that the steep slopes of asymmetrical dunes in the middle and upper

Towards the classification of eutrophic condition in estuaries

CSIR Research Space (South Africa)

Lemley, DA

2015-10-01

Full Text Available Water quality and ecological integrity of estuaries closely reflect activities within the entire upstream catchment. Much emphasis has been placed on the response of estuaries to anthropogenic stressors through the use of monitoring programmes. Key...

Nutrients, hypoxia and mass fishkill events in Tapi estuary, India.

Digital Repository Service at National Institute of Oceanography (India)

Ram, A.; JiyalalRam, M.J.; Rokade, M.A.; Bharti, S.; Vishwasrao, C.; Majithiya, D.

ecosystem (Villate et al. 2013). The flushing out of contaminants entering an estuary is further impacted due to impounding of water in dams, weirs and barrages for hydropower, navigation, aquaculture, diversion for urban water supply, agriculture, due...., 2008. Eutrophic waters, algal bloom and fish kill in fish farming areas in Bolinao, Pangasinan, Philippines. Marine Pollution Bulletin 57, 295–301 Sargaonkar, A., 2006. Estimation of land use specific runoff and pollutant concentration for Tapi...

Superstorm Sandy-related Morphologic and Sedimentologic Changes in an Estuarine System: Barnegat Bay-Little Egg Harbor Estuary, New Jersey

Science.gov (United States)

Miselis, J. L.; Ganju, N. K.; Navoy, A.; Nicholson, R.; Andrews, B.

2013-12-01

Despite the well-recognized ecological importance of back-barrier estuaries, the role of storms in their geomorphic evolution is poorly understood. Moreover, the focus of storm impact assessments is often the ocean shorelines of barrier islands rather than the exchange of sediment from barrier to estuary. In order to better understand and ultimately predict short-term morphologic and sedimentologic changes in coastal systems, a comprehensive research approach is required but is often difficult to achieve given the diversity of data required. An opportunity to use such an approach in assessing the storm-response of a barrier-estuary system occurred when Superstorm Sandy made landfall near Atlantic City, New Jersey on 29 October 2012. Since 2011, the US Geological Survey has been investigating water circulation and water-quality degradation in Barnegat Bay-Little Egg Harbor (BBLEH) Estuary, the southern end of which is approximately 25 kilometers north of the landfall location. This effort includes shallow-water geophysical surveys to map the bathymetry and sediment distribution within BBLEH, airborne topo-bathymetric lidar surveys for mapping the shallow shoals that border the estuary, and sediment sampling, all of which have provided a recent picture of the pre-storm estuarine geomorphology. We combined these pre-storm data with similar post-storm data from the estuary and pre- and post-storm topographic data from the ocean shoreline of the barrier island to begin to understand the response of the barrier-estuary system. Breaches in the barrier island resulted in water exchange between the estuary and the ocean, briefly reducing residence times in the northern part of the estuary until the breaches were closed. Few morphologic changes in water depths greater than 1.5 m were noted. However, morphologic changes observed in shallower depths along the eastern shoreline of the estuary are likely related to overwash processes. In general, surficial estuarine sediments

Investigating Anthropogenic Perturbations on Carbon Cycling in AN Urbanized Tropical West African Estuary

Science.gov (United States)

Atekwana, E. A.; Ali, H.; Ndondo, N.

2017-12-01

We conducted an axial survey of salinity, stable isotopes of oxygen (δ18O) of water, nitrates, pH, alkalinity, dissolved inorganic carbon (DIC) and stable isotopes of carbon (δ13C) of DIC in the Douala Estuary, Cameroon, West Africa. Our objective was to assess anthropogenic impact of pollution on carbon cycling in this urbanized tropical estuary. Salinity ranged from 0.03 to 23.95 and increased steeply from the head to 15 km, stayed nearly constant to 24 km, and then increased steadily to the mouth. The δ18O ranged from -0.4‰ to -5.0‰ and increased steadily from the head to13 km, then slowly to 24 km before increasing sharply to the mouth. The similar behaviour between salinity and δ18O was caused by dilution from the Mungo R. to the west and the Dibamba R. to the east. The nitrate concentrations ranged from 0 to 34 mg/L and behaved similarly to salinity, which was low at the head (0 - 4 km), increased steeply to 15 km and stayed nearly constant to 24 km before increasing sharply to mouth. The spatial distribution of nitrates indicate pollution from agricultural input through the Mungo R., sewage discharge along the urbanized Wouri R. and Dibamba R. and from industries and the port facility along the estuary. The alkalinity concentrations ranged from 12 to 60 mg/Kg and DIC concentrations ranged from 2.9 to 15.5 mg C/Kg, are both positively correlated (R2 = 0.94) and both increased from the estuary head towards the mouth. The salinity concentrations show a good positive correlation (R2 = 0.98) with DIC concentrations. The partial pressure of CO2 (pCO2) which was decreasing from the estuary head towards the mouth reverses at 10 km and increases down estuary towards the mouth. The pCO2 behaviour indicates that the axial increase in the DIC concentrations is from the addition of CO2, although mixing of ocean water with higher DIC concentrations can also explain this observation. The generation of CO2 in the water column is reflected in the pH which increased

Oil spill trajectory analysis for the Calcasieu Estuary

International Nuclear Information System (INIS)

Meselhe, E.A.; Barker, C.H.; Hodges, M.

2001-01-01

A three-dimensional hydrodynamic model (H3D) was used to determine how oil spills might travel and spread within the Calcasieu River Estuary which has heavy oil traffic. The Calcasieu River is located in the southwest corner of the State of Louisiana and houses valuable wetlands that provide both commercial and recreational fishing and wildlife value to the area. These wetlands also filter water and protect Louisiana's coast areas from hurricane storm surges. An oil spill would damage areas of marshes that would have devastating effects on the entire ecological system within the estuary. A Trajectory Analysis Planner (TAP) H3D computer model is under development by the Hazardous Materials Response Division of the National Oceanic and Atmospheric Administration (NOAA). TAP is a statistical planning tool that randomly samples historical hydrodynamic, hydrology and climatological data, to build up a database with biological and cleanup resource information. TAP can be used to predict which sites within the estuarine system will be most susceptible to oil spills of varying magnitudes, materials and locations. TAP can also estimate the time available for mitigation and remedial actions before the spill can impact the site. Hydrodynamics in the Calcasieu estuary is a combination of processes such as saltwater intrusion and response to water level fluctuations at an open boundary, as well as lake dynamics. H3D provides the three components of velocity, plus scalar quantities such as water levels, temperature and salinity distribution on a Cartesian three-dimensional grid. TAP was tested for spills of kerosene, non-weathering oil, crude oil, and gasoline and was able to perform reliable spill trajectory analysis. 12 refs., 9 figs

Sedimentary Records of Hyperpycnal Flows and the Influence of River Damming on Sediment Dynamics of Estuaries: Examples from the Nelson, Churchill, Moisie and Sainte-Marguerite Rivers (Canada)

Science.gov (United States)

St-Onge, G.; Duboc, Q.; Boyer-Villemaire, U.; Lajeunesse, P.; Bernatchez, P.

2015-12-01

Sediment cores were sampled in the estuary of the Nelson and Churchill Rivers in western Hudson Bay, as well as in the estuary of the Moisie and Sainte-Marguerite Rivers in Gulf of St. Lawrence in order to evaluate the impact of hydroelectric dams on the sedimentary regime of these estuaries. The gravity cores at the mouth of the Nelson River recorded several cm-thick rapidly deposited layers with a reverse to normal grading sequence, indicating the occurrence of hyperpycnal flows generated by major floods during the last few centuries. These hyperpycnal flows were probably caused by ice-jam formation, which can increase both the flow and the sediment concentration following the breaching of such natural dams. Following the construction of hydroelectric dams since the 1960s, the regulation of river discharge prevented the formation of hyperpycnal flows, and hence the deposition of hyperpycnites in the upper part of the cores. In the core sampled in the estuary of the Churchill River, only one hyperpycnite was recorded. This lower frequency may be due to the enclosed estuary of the Churchill River, its weaker discharge and the more distal location of the coring site.In the Gulf of St. Lawrence, grain size measurements allowed the identification of a major flood around AD 1844±4 years in box cores from both the Sainte-Marguerite and Moisie Rivers, whereas a drastic decrease in variations in the median grain size occurred around AD ~1900 in the estuary of the Sainte-Marguerite River, highlighting the offshore impact of the SM1 dam construction in the early 1900s. Furthermore, sedimentological variations in the box cores from both estuaries have been investigated by wavelet analysis and the sharp disappearance of high frequencies around AD 1900 in the estuary of the dammed river (Sainte-Marguerite River), but not in the estuary of the natural river (Moisie River), also provides evidence of the influence of dams on the sedimentary regime of estuaries.

Restoration of the Golden Horn Estuary (Halic).

Science.gov (United States)

Coleman, Heather M; Kanat, Gurdal; Aydinol Turkdogan, F Ilter

2009-12-01

Restoration of the iconic Golden Horn Estuary in Istanbul, Turkey was a substantial political, logistical, ecological, and social challenge. Forty years of uncontrolled industrial and urban growth resulted in thick layers of anoxic sediment, toxic bacteria, strong hydrogen sulfide odor, and ecologically unlivable conditions. The major components of restoration, spanning two decades, have included (1) demolition and relocation of industries and homes along the shore, (2) creation of wastewater infrastructure, (3) removal of anoxic sludge from the estuary, (4) removal of a floating bridge that impeded circulation, and (5) creation of cultural and social facilities. Although Turkey is not known as an environmental leader in pollution control, the sum of these efforts was largely successful in revitalizing the area through dramatic water quality improvement. Consequently, the estuary is once again inhabitable for aquatic life as well as amenable to local resource users and foreign visitors, and Istanbul has regained a lost sense of cultural identity. This paper focuses on literature review and personal interviews to discuss the causes of degradation, solutions employed to rehabilitate the estuary, and subsequent physicochemical, ecological, and social changes.

Alkaline Phosphatase Activity : an overlooked player on the phosphate behavior in macrotidal estuaries

Science.gov (United States)

Delmas, Daniel; Labry, Claire; Youenou, Agnes; Quere, Julien; Auguet, Jean Christophe; Montanie, Helene

2014-05-01

The non-conservative behavior of phosphate within the estuarine salinity gradient is essentially assigned to physico-chemical processes, such as desorption at low salinity and to benthic exchanges. Microbial phosphatase activity (APA), generally related to phosphate deficiency, is seldom studied in phosphate rich estuarine waters. In order to address the impact of microbial activity (bacterial abundance, production BSP, APA) on phosphate behavior, we studied these activities on a seasonal basis within the salinity gradient of two macrotidal estuaries presenting different levels of suspended solids. Whatever the season the Charente estuary is characterized by high levels of Suspended Particulate Matter (SPM > 1g.L-1), particularly in the Maximum Turbidity Zone (MTZ) located at the 5-10 psu. In this area characterized by high BSP and APA there is a significant increase of PO4 levels especially during summer. In the Aulne estuary the particle load is significantly lower (1/10) but high BSP and APA are equally recorded. In the highly turbid waters of the Charente estuary, active phytoplankton is virtually absent as pheopigments constitute up to 80% of the total pigments, particularly in the MTZ, therefore APA may essentially have a bacterial origin. In the Aulne estuary attached bacteria are dominant, both in numbers and production, and their distribution along the haline gradient perfectly follows those of APA and phosphate levels. These observations, associated with the very close relationships observed between APA, SPM and BSP, suggest that APA derive mainly from bacterial (attached) origin and operate at the expense of particulate phosphorus and hence contribute to PO4 regeneration, especially in spring and summer. Finally, as APA increased as PO4, whereas the reverse is observed in both fresh and marine waters, an original scheme for APA regulation, related to the large dominance of attached bacteria can be described for the estuarine waters.

Sources, Ages, and Alteration of Organic Matter in Estuaries.

Science.gov (United States)

Canuel, Elizabeth A; Hardison, Amber K

2016-01-01

Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river-estuary-coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters.

Protozooplankton characterization of two contrasting sites in a tropical coastal ecosystem (Guanabara Bay, RJ

Directory of Open Access Journals (Sweden)

Eli Ana Traversim Gomes

2007-03-01

Full Text Available Much time and resources have been invested in understanding plankton dynamics in Guanabara Bay (Brazil, but no attention has been devoted to the protozooplankton. To fulfill this lacuna, abundance and composition of protozooplankton were investigated from January to December - 2000 in fortnightly surface water samplings at two distinct water quality sites (Urca - closer to the bay entrance, more saline and cleaner waters; Ramos - inner reaches, hypereutrophic waters. The density at Urca (10³ - 10(5 cell.l-1 was one to three orders of magnitude lower than at Ramos (10(4 - 10(5 cell.l-1. A seasonal trend for nanoplankton and protozooplankton was more evident at Urca, but both sites had lower densities during the colder period. Small heterotrophic dinoflagellates (20-30 mm were dominant in over 50% of the samples. The protozooplankton abundance and composition reflected the distinct trophic conditions states found at the bay. During the wet-warm season, non-oligotrich ciliates were representative of Ramos site with Gymnodiniaceae dinoflagellates, while tintinnids and heterotrophic dinoflagellates were predominantly found at Urca mainly during the dry-cold season. This first descriptive study towards the understanding of the intricate relationships among the microbial food web components reveals that protozooplankton can be a good indicator of water quality conditions at the bay.Muito tem sido investido para entender a dinâmica do plâncton da Baía de Guanabara (Brasil, estuário tropical com sérios problemas ambientais, mas pouco se sabe sobre o protozooplâncton. Preenchendo esta lacuna, a composição e abundância do protozooplâncton (ciliados, flagelados heterotróficos foram investigadas em 2000, por meio de amostragens subsuperficiais, quinzenais, em dois locais com qualidade distinta de água (Urca - entrada da baía, águas mais salinas e limpas; Ramos - região mais interna, águas hipereutróficas e menos salinas. A densidade na Urca

Linking behavior, physiology, and survival of Atlantic Salmon smolts during estuary migration

Science.gov (United States)

Stich, Daniel S.; Zydlewski, Gayle B.; Kocik, John F.; Zydlewski, Joseph D.

2015-01-01

Decreased marine survival is identified as a component driver of continued declines of Atlantic Salmon Salmo salar. However, estimates of marine mortality often incorporate loss incurred during estuary migration that may be mechanistically distinct from factors affecting marine mortality. We examined movements and survival of 941 smolts (141 wild and 800 hatchery-reared fish) released in freshwater during passage through the Penobscot River estuary, Maine, from 2005 to 2013. We related trends in estuary arrival date, movement rate, and survival to fish characteristics, migratory history, and environmental conditions in the estuary. Fish that experienced the warmest thermal history arrived in the estuary 8 d earlier than those experiencing the coolest thermal history during development. Estuary arrival date was 10 d later for fish experiencing high flow than for fish experiencing low flow. Fish released furthest upstream arrived in the estuary 3 d later than those stocked further downstream but moved 0.5 km/h faster through the estuary. Temporally, movement rate and survival in the estuary both peaked in mid-May. Spatially, movement rate and survival both decreased from freshwater to the ocean. Wild smolts arrived in the estuary later than hatchery fish, but we observed no change in movement rate or survival attributable to rearing history. Fish with the highest gill Na+, K+-ATPase activity incurred 25% lower mortality through the estuary than fish with the lowest gill Na+, K+-ATPase activity. Smolt survival decreased (by up to 40%) with the increasing number of dams passed (ranging from two to nine) during freshwater migration. These results underscore the importance of physiological preparedness on performance and the delayed, indirect effects of dams on survival of Atlantic Salmon smolts during estuary migration, ultimately affecting marine survival estimates.

Centro de Medicina Nuclear da Guanabara, CMNG, Rio de Janeiro. Activities, safety and radiation protection in medical practices

International Nuclear Information System (INIS)

Rocha, A. F.G.; Loureiro, M.V.D.M.; Santos, C.S.B.; Costa, T.S.; Maciel, O. S.; Rozental, J.J.

2008-01-01

Full text: The Center of Nuclear Medicine of Guanabara (CMNG), established in the city of Rio de Janeiro, is a private company who acts for more than 30 years in the area of images and nuclear medicine diagnosis using radioactive tracers for examinations initially 'in vivo' and treatment of the hyperthyroid and thyroid cancer, and later extending its area of activities using equipment producing ionizing or non-ionizing radiation. The CMNG has installed and operated the first computerized tomography in the city of Rio de Janeiro by the year 70, and now also implementing its activities by operating a PET-CT (positron emission tomography). In the City of Rio de Janeiro, from the head quarter, the CMNG manages several offices localized in important points of the City. At the present time the CMNG works with sophisticated equipment as tomography's, mammography's, densitometers, X-Ray and fluoroscopy. The CMNG's PET equipment is connected to a computerized multislice tomography that use the integration of anatomical information provided by the CT scan with the metabolic ones allows to the accomplishment of the two methods sequentially supplied by the PET, increasing the certainty in the localization of the results found in the examinations. In such a way it improves significantly the accuracy, the sensitivity of the negative predictive value of both the methods separately. Still in the medical diagnosis for images, but without the use of ionizing radiations, the CMNG operates diverse devices as ultrasound and nuclear magnetic resonance. To operate all the systems the CMNG has equipped with multi discipline of professionals, being included doctors, pharmacists', biologists, biomedical, engineers, and specialists in computer science, quality control and staff of technical level properly trained for support tasks. The purpose to present this paper is to attend the call for papers contained in the institutional objective of the IRPA 12 Congress for exchange of experience and

Uso de SIG na avaliação da contaminação por chumbo e cobre no Canal do Cunha e no oeste da Baía de Guanabara , Rio de Janeiro, RJ.

OpenAIRE

SANTOS, Fábio Ventura dos; BORGES, Renata Coura; VIEIRA, Paloma da Conceição; SIMÕES FILHO, Francisco Fernando Lamego; LAPA, Celso Marcelo Franklin

2013-01-01

As well as other subbasins of Guanabara Bay, the Canal do Cunha's sub - basin, located in the city of Rio de Janeiro, suffered a severe environmental degradation as from the 1950s due to the accelerated urban - industrial development. Having a fluvial dynamics changed - by deforestation, dredging, occupying valleys and corrections - the channel is responsible for the flow of effluents and sediments that contribute to environmental degradation and has direct influence on ...

Eco-morphological problems in the Yangtze Estuary and the Western Scheldt

NARCIS (Netherlands)

De Vriend, H.J.; Wang, Z.B.; Ysebaert, T.; Herman, P.M.J.; Ding, P.X.

2011-01-01

This paper compares the Yangtze Estuary in China and the Western Scheldt Estuary in The Netherlands by their morphodynamic and ecological systems, their engineering works and estuarine management issues, and the major challenges in studying them. Physically speaking, the two estuaries are very

An analytical solution for tidal propagation in the Yangtze Estuary, China

Directory of Open Access Journals (Sweden)

E. F. Zhang

2012-09-01

Full Text Available An analytical model for tidal dynamics has been applied to the Yangtze Estuary for the first time, to describe the tidal propagation in this large and typically branched estuary with three-order branches and four outlets to the sea. This study shows that the analytical model developed for a single-channel estuary can also accurately describe the tidal dynamics in a branched estuary, particularly in the downstream part. Within the same estuary system, the North Branch and the South Branches have a distinct tidal behaviour: the former being amplified demonstrating a marine character and the latter being damped with a riverine character. The satisfactory results for the South Channel and the South Branch using both separate and combined topographies confirm that the branched estuary system functions as an entity. To further test these results, it is suggested to collect more accurate and dense bathymetric and tidal information.

Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

International Nuclear Information System (INIS)

Musenze, Ronald S.; Werner, Ursula; Grinham, Alistair; Udy, James; Yuan, Zhiguo

2014-01-01

Methane (CH 4 ) and nitrous oxide (N 2 O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH 4 and N 2 O all-year-round. Dissolved N 2 O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH 4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH 4 and N 2 O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N 2 O saturation significantly increased with NO x concentrations (r 2 = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N 2 O m −2 d −1 and 0.3 to 27.9 mg CH 4 m −2 d −1 . Total emissions (CO 2 -e) were N 2 O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that in tropical rivers and polluted estuaries. • Emissions are dominated by N2O, which

Impact of climate variability on ichthyoplankton communities: An example of a small temperate estuary

Science.gov (United States)

Primo, Ana Lígia; Azeiteiro, Ulisses Miranda; Marques, Sónia Cotrim; Pardal, Miguel Ângelo

2011-03-01

Recent variations in the precipitation regime across southern Europe have led to changes in river fluxes and salinity gradients affecting biological communities in most rivers and estuaries. A sampling programme was developed in the Mondego estuary, Portugal, from January 2003 to December 2008 at five distinct sampling stations to evaluate spatial, seasonal and inter-annual distributions of fish larvae. Gobiidae was the most abundant family representing 80% of total catch and Pomatoschistus spp. was the most important taxon. The fish larval community presented a clear seasonality with higher abundances and diversities during spring and summer seasons. Multivariate analysis reinforced differences among seasons but not between years or sampling stations. The taxa Atherina presbyter, Solea solea, Syngnathus abaster, Crystallogobius linearis and Platichthys flesus were more abundant during spring/summer period while Ammodytes tobianus, Callionymus sp., Echiichthys vipera and Liza ramada were more abundant in autumn/winter. Temperature, chlorophyll a and river flow were the main variation drivers observed although extreme drought events (year 2005) seemed not to affect ichthyoplankton community structure. Main changes were related to a spatial displacement of salinity gradient along the estuarine system which produced changes in marine species distribution.

Distribuição espacial de ferro, cobre e chumbo em sedimentos de manguezal em um gradiente de degradação na Baía de Guanabara (Estado do Rio de Janeiro)

OpenAIRE

Borges,Anderson C.; Dias,Jailson C.; Machado,Wilson; Patchineelam,Sambasiva R.; Sella,Silvia M.

2007-01-01

Iron, copper and lead distribution was evaluated in sediment cores from a disturbed mangrove area in Guanabara Bay: a core from a seaward site where mangrove vegetation was removed ~20 yr before sampling (MD); a core from an intermediate site with dead vegetation, apparently due to insect attack (MP), and a core from a landward site with living vegetation (MV). Metal concentrations showed increasing values seaward while organic matter content showed an inverse trend, displaying a negative cor...

Skagit IMW - Skagit River Estuary Intensively Monitored Watershed Project

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This study evaluates system-level effects of several estuary restoration projects on juvenile Chinook salmon production in the Skagit River estuary. The monitoring...

Distribuição geográfica da fauna e flora da Baía de Guanabara Geographic distribution of the flora and the fauna of the Guanabara Bay

Directory of Open Access Journals (Sweden)

Lejeune P. H. de Oliveira

1947-09-01

Full Text Available The author studied, the horizontal and vertical distribution of most common part of the flora and fauna of the bay of Guanabara at Rio de Janeiro. In this paper the eulittoral, poly, meso and oligohaline regions were localised and studied; and the first chart of its distribution was presented (fig. 2. The salinity of superficial waters was established through determinations based on 30 trips inside the buy for collecting biological materials. Some often 409 determinations which were previous reported together with the present ones served for the eleboration of a salinity map of the bay of Guanabara (fig. 1. This map of fig. 2 shows the geographic locations of the water regions. EULITTORAL WATER REGIME — Fig. 3 shows the diagram scheme of fauna and flora of this regime. Sea water salinity 34/1.000, density mean 1.027, transparent greenish waters, sea coast with moderate bursting waves. Limpid sea shore with white sand, gneiss with the big barnacle Tetraclita squamosa var. stalactifera (Lam. Pilsbry. Vertical distributions: barna¬cles layers with a green region in which are present the oyster Ostrea pa-rasitica L., the barnacles Tetraclita, Chthamalus, Balanus tintinnabulum var. tintinnabulum (L. e var. antillensis Pilsbry in connection with several mollusca and the sea beatle Isopoda Lygia sp. Covered by water and exposed to air by the tidal ritms, there is a stratum of brown animals that is the layer of mussels Mytilus perna L., with others brown and chestnut animals : the Crustacea Pachygrapsus, the little crab Porcellana sp., the stone crab Me-nippe nodifrons Stimpson, the sea stars Echinaster brasiliensis (Mull. & Tr., Astropecten sp. and the sea anemones Actinia sp. Underneath and never visible there is a subtidal region with green tubular algae of genus Codium and amidst its bunches the sea urchin Lycthchinus variegatus (Agass. walks and more deeply there are numerous sand-dollars Encope emarginata (Leske. The microplancton of this

Are large macroalgal blooms necessarily bad? Nutrient impacts on seagrass in upwelling-influenced estuaries.

Science.gov (United States)

Hessing-Lewis, Margot L; Hacker, Sally D; Menge, Bruce A; McConville, Sea-oh; Henderson, Jeremy

2015-07-01

Knowledge of nutrient pathways and their resulting ecological interactions can alleviate numerous environmental problems associated with nutrient increases in both natural and managed systems. Although not unique, coastal systems are particularly prone to complex ecological interactions resulting from nutrient inputs from both the land and sea. Nutrient inputs to coastal systems often spur ulvoid macroalgal blooms, with negative consequences for seagrasses, primarily through shading, as well as through changes in local biogeochemistry. We conducted complementary field and mesocosm experiments in an upwelling-influenced estuary, where marine-derived nutrients dominate, to understand the direct and indirect effects of nutrients on the macroalgal-eelgrass (Zostera marina L.) interaction. In the field experiment, we found weak evidence that nutrients and/or macroalgal treatments had a negative effect on eelgrass. However, in the mesocosm experiment, we found that a combination of nutrient and macroalgal treatments led to strongly negative eelgrass responses, primarily via indirect effects associated with macroalgal additions. Together, increased total light attenuation and decreased sediment oxygen levels were associated with larger effects on eelgrass than shading alone, which was evaluated using mimic algae treatments that did not alter sediment redox potential. Nutrient addition in the mesocosms directly affected seagrass density; biomass, and morphology, but not as strongly as macroalgae. We hypothesize that the contrary results from these parallel experiments are a consequence of differences in the hydrodynamics between field and mesocosm settings. We suggest that the high rates of water movement and tidal submersion of our intertidal field experiments alleviated the light reduction and negative biogeochemical changes in the sediment associated with macroalgal canopies, as well as the nutrient effects observed in the mesocosm experiments. Furthermore, adaptation

Heavy Metallic Element Distribution in Cisadane River Estuary's Water and Sediment

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M. Taufik Kaisupy

2006-04-01

Full Text Available Observation of heavy metallic elements in Cisadane River Estuary has been done in July and November 2005. The results show that heavy metallic elements content in seawater is lower and still below the treshold value stated by government for fisheries. There was an indication of heavy metallic elements on sediment. Distribution of Pb on July and of Cu on November 2005 were found higher near the coast and decrease towards the sea, and commonly were found in front of estuary such as Cisadane, Muara Saban and Tanjung Pasir. High Pb and Zn distributions on November 2005 were found only in front of Cisadane estuary. Cd distribution of Cisadane estuary was constant at all station but did not show any correlation with the distance of station and estuary. The Cd content on July and November 2005 is lower than 0,001 ppm. Generally, heavy metallic elements content have a uniform distribution at all stations inspite of its distance to estuary.

Benthos of Beypore and Korapuzha estuaries of North Kerala

Digital Repository Service at National Institute of Oceanography (India)

Devi, K.S.; Sankaranarayanan, V.N.; Venugopal, P.

The benthos from Beypore and Korapuzha estuaries were studied for one year. Environmental features, sediment characteristics and organic carbon content were estimated. Benthic density was high during monsoon and postmonsoon in both the estuaries...

Variations of dissolved oxygen in Mandovi and Zuari estuaries

Digital Repository Service at National Institute of Oceanography (India)

DeSousa, S.N.; SenGupta, R.

During non-monsoon months the estuaries were well mixed showing uniform oxygen concentrations from surface to bottom. However, during monsoon months both the estuaries showed stratified conditions with surface water showing high oxygen concentration...

75 FR 2517 - Notice of Solicitation for Estuary Habitat Restoration Program

Science.gov (United States)

2010-01-15

..., wastewater treatment plant upgrades, combined sewer outfalls, and non-point source pollution projects such as... Estuary Restoration Act of 2000, Title I of the Estuaries and Clean Waters Act of 2000 (Pub. L. 106-457... with fresh water from land drainage.'' Estuary also includes the ``* * * near coastal waters and...

Identifying resuspended sediment in an estuary using the 228Th/232Th activity ratio: the fate of lagoon sediment in the Bega River estuary, Australia

International Nuclear Information System (INIS)

Hancock, G.J.

2000-01-01

Thorium-series nuclides ( 228 Th and 232 Th) have been used to identify resuspended sediment in the Bega River estuary, south-eastern Australia. A non-conservative increase in concentration of suspended sediment of water in the vicinity of mid-estuary back-flow lagoons was associated with a decrease in the 228 Th/ 232 Th activity ratio (AR) of the suspended sediment. The lagoon sediment is characterized by a low estuarine 228 Th/ 232 Th signature, distinguishing it from freshwater suspended sediment recently delivered to the estuary, and identifying it as the likely source of the additional suspended sediment. Sediment-core 210 TPb profiles show that the lagoons are accumulating sediment, presumably during high river-flow events. However this study indicates that during intervening periods of low flow, 40% of sediment deposited in the lagoons is subsequently resuspended and exported to the lower estuary, and possibly to the ocean. The utility of the 228 Th/ 232 Th AR to quantify sediment resuspension in estuaries is likely to be estuary-dependent, and is controlled by the extent of scavenging of dissolved 228 Th by suspended particles. Copyright (2000) CSIRO Publishing

Modelling extreme climatic events in Guadalquivir Estuary ( Spain)

Science.gov (United States)

Delgado, Juan; Moreno-Navas, Juan; Pulido, Antoine; García-Lafuente, Juan; Calero Quesada, Maria C.; García, Rodrigo

2017-04-01

Extreme climatic events, such as heat waves and severe storms are predicted to increase in frequency and magnitude as a consequence of global warming but their socio-ecological effects are poorly understood, particularly in estuarine ecosystems. The Guadalquivir Estuary has been anthropologically modified several times, the original salt marshes have been transformed to grow rice and cotton and approximately one-fourth of the total surface of the estuary is now part of two protected areas, one of them is a UNESCO, MAB Biosphere Reserve. The climatic events are most likely to affect Europe in forthcoming decades and a further understanding how these climatic disturbances drive abrupt changes in the Guadalquivir estuary is needed. A barotropic model has been developed to study how severe storm events affects the estuary by conducting paired control and climate-events simulations. The changes in the local wind and atmospheric pressure conditions in the estuary have been studied in detail and several scenarios are obtained by running the model under control and real storm conditions. The model output has been validated with in situ water elevation and good agreement between modelled and real measurements have been obtained. Our preliminary results show that the model demonstrated the capability describe of the tide-surge levels in the estuary, opening the possibility to study the interaction between climatic events and the port operations and food production activities. The barotropic hydrodynamic model provide spatially explicit information on the key variables governing the tide dynamics of estuarine areas under severe climatic scenarios . The numerical model will be a powerful tool in future climate change mitigation and adaptation programs in a complex socio-ecological system.

Electronic tagging of green sturgeon reveals population structure and movement among estuaries

Science.gov (United States)

Lindley, S.T.; Erickson, D.L.; Moser, M.L.; Williams, G.; Langness, O.P.; McCovey, B.W.; Belchik, M.; Vogel, D.; Pinnix, W.; Kelly, J.T.; Heublein, J.C.; Klimley, A.P.

2011-01-01

Green sturgeon Acipenser medirostris spend much of their lives outside of their natal rivers, but the details of their migrations and habitat use are poorly known, which limits our understanding of how this species might be affected by human activities and habitat degradation.We tagged 355 green sturgeon with acoustic transmitters on their spawning grounds and in known nonspawning aggregation sites and examined their movement among these sites and other potentially important locations using automated data-logging hydrophones. We found that green sturgeon inhabit a number of estuarine and coastal sites over the summer, including the Columbia River estuary, Willapa Bay, Grays Harbor, and the estuaries of certain smaller rivers in Oregon, especially the Umpqua River estuary. Green sturgeon from different natal rivers exhibited different patterns of habitat use; most notably, San Francisco Bay was used only by Sacramento River fish, while the Umpqua River estuary was used mostly by fish from the Klamath and Rogue rivers. Earlier work, based on analysis of microsatellite markers, suggested that the Columbia River mixed stock was mainly composed of fish from the Sacramento River, but our results indicate that fish from the Rogue and Klamath River populations frequently use the Columbia River as well. We also found evidence for the existence of migratory contingentswithin spawning populations.Our findings have significant implications for the management of the threatened Sacramento River population of green sturgeon, which migrates to inland waters outside of California where anthropogenic impacts, including fisheries bycatch and water pollution, may be a concern. Our results also illustrate the utility of acoustic tracking to elucidate the migratory behavior of animals that are otherwise difficult to observe. ?? American Fisheries Society 2011.

Future extreme water levels and floodplains in Gironde Estuary considering climate change

Science.gov (United States)

Laborie, V.; Hissel, F.; Sergent, P.

2012-04-01

of floodplains in Gironde Estuary, taking into account IPCC scenario A1B, under the same assumptions, it appears that the impact of the climate change on the quantiles of water levels in floodplains depends on the sea level rise over the period considered ([2010; 2039], [2040; 2069], [2070; 2099]) and that areas which are not flooded today for weak return periods become submerged towards 2100. The neighborhood of Le Verdon undergoes a negative impact only in the medium and long term. For the period [2010; 2039], a small reduction of floodplains can be observed in quantiles of water levels for all return periods. Under those assumptions, in the area of Bordeaux, significant effects would be felt along the road RN230 towards 2100. The effects of the discharges and dike breaching will have to be studied in order to precise these results.

Report on the workshop examining the potential effects of hydroelectric development on Beluga of the Nelson River Estuary, Winnipeg, Manitoba, November 6 and 7, 1990

International Nuclear Information System (INIS)

Lawrence, M.J.; Paterson, M.; Baker, R.F.; Schmidt, R.

1992-01-01

A summary is presented of discussions and conclusions at a workshop held to examine the potential effects of hydroelectric development on beluga whales of the Nelson River estuary in Manitoba. Background information is provided on the estuary, beluga whales and their use of arctic and subarctic estuaries, and hydroelectric development on the Nelson River. Potential impacts of such development on the whales are reviewed in the categories of direct effects of changes in physical-chemical conditions (temperature and discharge), indirect effects of disturbances mediated through the food chain, and effects on socioeconomic conditions that may affect beluga whales. Since the biology of beluga whales and other phenomena of interest in this study are poorly known, recommendations are made for research and monitoring activities in the Nelson River estuary. In general, the workshop participants felt that changes in the estuary due to hydroelectric development would not be large enough to affect beluga whales strongly. 34 refs., 1 fig

Aggregate Settling Velocities in San Francisco Estuary Margins

Science.gov (United States)

Allen, R. M.; Stacey, M. T.; Variano, E. A.

2015-12-01

One way that humans impact aquatic ecosystems is by adding nutrients and contaminants, which can propagate up the food web and cause blooms and die-offs, respectively. Often, these chemicals are attached to fine sediments, and thus where sediments go, so do these anthropogenic influences. Vertical motion of sediments is important for sinking and burial, and also for indirect effects on horizontal transport. The dynamics of sinking sediment (often in aggregates) are complex, thus we need field data to test and validate existing models. San Francisco Bay is well studied and is often used as a test case for new measurement and model techniques (Barnard et al. 2013). Settling velocities for aggregates vary between 4*10-5 to 1.6*10-2 m/s along the estuary backbone (Manning and Schoellhamer 2013). Model results from South San Francisco Bay shoals suggest two populations of settling particles, one fast (ws of 9 to 5.8*10-4 m/s) and one slow (ws of Brand et al. 2015). While the open waters of San Francisco Bay and other estuaries are well studied and modeled, sediment and contaminants often originate from the margin regions, and the margins remain poorly characterized. We conducted a 24 hour field experiment in a channel slough of South San Francisco Bay, and measured settling velocity, turbulence and flow, and suspended sediment concentration. At this margin location, we found average settling velocities of 4-5*10-5 m/s, and saw settling velocities decrease with decreasing suspended sediment concentration. These results are consistent with, though at the low end of, those seen along the estuary center, and they suggest that the two population model that has been successful along the shoals may also apply in the margins.

Estuary-ocean connectivity: fast physics, slow biology.

Science.gov (United States)

Raimonet, Mélanie; Cloern, James E

2017-06-01

Estuaries are connected to both land and ocean so their physical, chemical, and biological dynamics are influenced by climate patterns over watersheds and ocean basins. We explored climate-driven oceanic variability as a source of estuarine variability by comparing monthly time series of temperature and chlorophyll-a inside San Francisco Bay with those in adjacent shelf waters of the California Current System (CCS) that are strongly responsive to wind-driven upwelling. Monthly temperature fluctuations inside and outside the Bay were synchronous, but their correlations weakened with distance from the ocean. These results illustrate how variability of coastal water temperature (and associated properties such as nitrate and oxygen) propagates into estuaries through fast water exchanges that dissipate along the estuary. Unexpectedly, there was no correlation between monthly chlorophyll-a variability inside and outside the Bay. However, at the annual scale Bay chlorophyll-a was significantly correlated with the Spring Transition Index (STI) that sets biological production supporting fish recruitment in the CCS. Wind forcing of the CCS shifted in the late 1990s when the STI advanced 40 days. This shift was followed, with lags of 1-3 years, by 3- to 19-fold increased abundances of five ocean-produced demersal fish and crustaceans and 2.5-fold increase of summer chlorophyll-a in the Bay. These changes reflect a slow biological process of estuary-ocean connectivity operating through the immigration of fish and crustaceans that prey on bivalves, reduce their grazing pressure, and allow phytoplankton biomass to build. We identified clear signals of climate-mediated oceanic variability in this estuary and discovered that the response patterns vary with the process of connectivity and the timescale of ocean variability. This result has important implications for managing nutrient inputs to estuaries connected to upwelling systems, and for assessing their responses to changing

Physical biological coupling in the Pearl River Estuary

Science.gov (United States)

Harrison, Paul J.; Yin, Kedong; Lee, J. H. W.; Gan, Jianping; Liu, Hongbin

2008-07-01

The Pearl River Estuary is a subtropical estuary and the second largest in China based on discharge volume from the Pearl River. Processes in the estuary vary spatially and temporally (wet vs dry season). In the dry season at the head of the estuary, hypoxic and nearly anoxic conditions occur and NH 4 reaches >600 μM, NO 3 is ˜300 μM and nitrite is ˜60 μM indicating that nitrification and denitrification may be important dry season processes in the region extending 40 km upstream of the Humen outlet. There are very few biological studies conducted in this upper section of the estuary in either the dry or wet seasons and hence there is a need for further research in this region of the river. In the wet season, the salinity wedge extends to the Hongqimen outlet and oxygen is low (35-80% saturation). Nitrate is ˜100 μM, silicate ˜140 μM; and phosphate is relatively low at ˜0.5 μM, yielding an N:P ratio up to ˜200:1 in summer. Nutrients decrease in the lower estuary and primary productivity may become potentially P-limited. Eutrophication is not as severe as one would expect from the nutrient inputs from the Pearl River and from Hong Kong's sewage discharge. This estuary shows a remarkable capacity to cope with excessive nutrients. Physical processes such as river discharge, tidal flushing, turbulent dispersion, wind-induced mixing, and estuarine circulation play an important role in controlling the production and accumulation of algal blooms and the potential occurrence of hypoxia. Superimposed on the physical processes of the estuary are the chemical and biological processes involved in the production of the bloom. For example, the 100N:1P ratio indicates that P potentially limits the amount of algal biomass (and potential biological oxygen demand) in summer. While extended periods of hypoxia are rare in Hong Kong waters, episodic events have been reported to occur during late summer due to factors such as low wind, high rainfall and river discharge which

Penobscot Estuary (Maine) Monitoring

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NOAA's NEFSC collects fisheries data from the Penobscot Estuary using several types of fishing gear. The data is used to determine species presence, relative...

Methane distribution and methane oxidation in the water column of the Elbe estuary, Germany

Czech Academy of Sciences Publication Activity Database

Matoušů, Anna; Osudar, R.; Šimek, Karel; Bussmann, I.

2017-01-01

Roč. 79, č. 3 (2017), s. 443-458 ISSN 1015-1621 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : estuary * methane * methane budget * ethane oxidation * River Elbe Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 2.821, year: 2016

The effects of wastewater discharges on the functioning of a small temporarily open/closed estuary

Science.gov (United States)

Lawrie, Robynne A.; Stretch, Derek D.; Perissinotto, Renzo

2010-04-01

Wastewater discharges affect the functioning of small temporarily open/closed estuaries (TOCEs) through two main mechanisms: (1) they can significantly change the water balance by altering the quantity of water inflows, and (2) they can significantly change the nutrient balance and hence the water quality. This study investigated the bio-physical responses of a typical, small TOCE on the east coast of South Africa, the Mhlanga Estuary. This estuary receives significant inflows of treated effluent from upstream wastewater treatment works. Water and nutrient budgets were used together with biological sampling to investigate changes in the functioning of the system. The increase in inflows due to the effluent discharges has significantly increased the mouth breaching frequency. Furthermore, when the mouth closes, the accumulation of nutrients leads to eutrophication and algal blooms. A grey water index, namely the proportion of effluent in the estuary and an indicator of the additional nutrient inputs into the estuary, reached high values (≳50%) during low flow regimes and when the mouth was closed. In these hyper-eutrophic conditions (DIN and DIP concentrations up to 457 μM and 100 μM respectively), field measurements showed that algal blooms occurred within about 14 days following closure of the mouth (chlorophyll-a concentrations up to 375 mg chl-a m -3). Water and nutrient balance simulations for alternative scenarios suggest that further increases in wastewater discharges would result in more frequent breaching events and longer open mouth conditions, but the occurrence of hyper-eutrophic conditions would initially intensify despite more frequent openings. The study indicates how water and nutrient balance simulations can be used in the planning and impact assessment of wastewater treatment facilities.

Evolution of Swarna estuary and its impact on braided islands and estuarine banks, Southwest coast of India

Digital Repository Service at National Institute of Oceanography (India)

AvinashKumar; Jayappa, K.S.; Vethamony, P.

Qualitative and quantitative evolution of the Swarna estuary, Karnataka, India during the past 38 years (1967–2005), has been analysed by integrating the results of field surveys, satellite images, hydrodynamic modelling and topographic data in GIS...

Community structure of benthic macroinvertebrates inhabiting a highly stratified Mediterranean estuary

Directory of Open Access Journals (Sweden)

Alfonso Nebra

2011-04-01

Full Text Available The community composition and spatial distribution of benthic macroinvertebrates were studied along the Ebro estuary, a highly stratified estuary located in the NE Iberian Peninsula. During the last decade the oligotrophication process occurring in the lower Ebro River and its estuary has allowed a complex benthic macroinvertebrate community to become established; these results contrast with the poor community found there in the early nineties. A total of 214 taxa were identified, and polychaetes dominated the community both in abundance and species richness. The results showed spatial differences in the structure and composition of macroinvertebrates, which suggests that there are two distinct communities along the estuary. Each community was found in a specific stretch (upper and lower estuary in function of the presence of the salt wedge. The macrobenthos of the upper estuary was dominated by freshwater taxa, but some euryhaline species were also found. The lower estuary showed a marine community typical of shallow Mediterranean environments. The transition between these two communities fits an ecotone model. The highest abundances, richness and diversities were recorded at the lower estuarine stations, especially those closer to the river mouth, whereas the lowest values corresponded to the stations adjacent to the tip of the salt wedge.

Continuous resistivity profiling data from the Corsica River Estuary, Maryland

Science.gov (United States)

Cross, V.A.; Bratton, J.F.; Worley, C.R.; Crusius, J.; Kroeger, K.D.

2011-01-01

Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine its importance in nutrient delivery to the Chesapeake Bay. The Corsica River Estuary represents a coastal lowland setting typical of much of the eastern bay. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the lower estuary in April and May 2007. Resource managers are concerned about nutrients that are entering the estuary via SGD that may be contributing to eutrophication, harmful algal blooms, and fish kills. Techniques employed in the study included continuous resistivity profiling (CRP), piezometer sampling of submarine groundwater, and collection of a time series of radon tracer activity in surface water. A CRP system measures electrical resistivity of saturated subestuarine sediments to distinguish those bearing fresh water (high resistivity) from those with saline or brackish pore water (low resistivity). This report describes the collection and processing of CRP data and summarizes the results. Based on a grid of 67.6 kilometers of CRP data, low-salinity (high-resistivity) groundwater extended approximately 50-400 meters offshore from estuary shorelines at depths of 5 to >12 meters below the sediment surface, likely beneath a confining unit. A band of low-resistivity sediment detected along the axis of the estuary indicated the presence of a filled paleochannel containing brackish groundwater. The meandering paleochannel likely incised through the confining unit during periods of lower sea level, allowing the low-salinity groundwater plumes originating from land to mix with brackish subestuarine groundwater along the channel margins and to discharge. A better understanding of the spatial variability and geological controls of submarine groundwater flow beneath the Corsica River Estuary could lead to improved models and mitigation strategies for nutrient over-enrichment in the

Contamination and restoration of an estuary affected by phosphogypsum releases

International Nuclear Information System (INIS)

Villa, M.; Mosqueda, F.; Hurtado, S.; Mantero, J.; Manjon, G.; Perianez, R.; Vaca, F.; Garcia-Tenorio, R.

2009-01-01

The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides 226 Ra and 210 Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of 210 Pb and 226 Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for 226 Ra and 210 Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary can be performed via natural

Influence of the Three Gorges Project on saltwater intrusion in the Yangtze River Estuary

Science.gov (United States)

An, Qiang; Wu, Yanqing; Taylor, Shauna; Zhao, Bin

2009-02-01

The Three Gorges Project (TGP) is a transcentury project that has aroused world attention. It is expected that the flow velocity and runoff of the Yangtze River will be changed after the project has been accomplished. Consequently, however, the ecological environment in the Yangtze River Basin, particularly in the estuary region, will be affected. Salinity intrusion into the Yangtze River estuary, in general, is mostly affected by the Yangtze River discharge and its external tidal level. This paper focuses on examining the influence of changes in runoff on salinity value. The question, to which should be paid attention is: how is the interaction between changes in runoff of the Yangtze River and salinity distribution in the Yangtze River estuary, China? In this research, a three-dimensional model has been used to identify the effects of runoff change on salinity distribution. The drawn conclusion is that the change of salinity is influenced by discharge variation. Positive and negative impacts of TGP would both turn up but in different period. In sum, TGP is in favor of restraining saltwater intrusion. Nevertheless a suitable method should be found to resolve its negative influences.

Dynamics of intertidal flats in the Loire estuary

Science.gov (United States)

Kervella, Stephane; Sottolichio, Aldo; Bertier, Christine

2014-05-01

Tidal flats form at the edges of many tidal estuaries, and are found in broad climatic regions. Their evolution plays a fundamental role in maintaining the morphodynamic equilibrium of an estuary. The Loire estuary is one of the largest macrotidal systems of the french atlantic coast. Since 200 years, its geometry has been drastically modified through channeling, deepening, embanking, infilling of secondary channels, etc. These works altered many intertidal areas. In the recent years, efforts for the rectification of the morphology have been made in order to restore the ecology of the estuary. In this context, it is crucial to better understand the dynamics of intertidal flats, still poorly understood in this estuary. The aim of this work is to analyse a series of original observations conducted for the first time in two intertidal flats of the central Lore estuary between 2008 and 2010. The tidal flats are situated in the northern bank, at 12 and 17 km upstream from the mouth respectively. Six Altus altimeters were deployed at two cross shore transects, measuring continuously and at a high-frequency bed altimetry and water level, providing information on tide and waves. At the semi-diurnal tidal scale, the surficial sediment of intertidal flats is permanently mobilized. Altimetry variations are low, and their amplitude varies as a function of tides and river flow. At the scale of several months, the sedimentation is controlled by the position of the turbidity maximum (and therefore by the river flow) and also by the tidal amplitude. During low river flow periods, altimetry variations are only due to tidal cycles. During decaying tides, suspended sediment settle mainly on the lower part of the tidal flats, forming fluid mud layers of several cm thick, which can consolidate rapidly; under rising tides, the increasing of tidal currents promotes erosion. During periods of high river flow, the turbidity maximum shifts to the lower estuary. The higher suspended sediment

Estuary-dependence of larval fishes in a non-estuary associated South African surf zone: evidence for continuity of surf assemblages

Science.gov (United States)

Strydom, Nadine A.; d'Hotman, Bruce D.

2005-04-01

Larval fishes were collected in the Cape Padrone surf zone on the southeast coast of South Africa, using a modified small-mesh seine net. The aim of the study was to assess the composition of fish larvae, with respect to their association with estuaries, in a surf zone that was not in close proximity to an estuary (>5 km). Sampling took place bimonthly during diurnal spring low tides between March and July 2003. In total, 544 fish were caught in the surf zone, comprising 14 families represented by 19 positively identified species, as well as an additional two species that were differentiated but remain unidentified. The families Mugilidae (65%) and Sparidae (26%) dominated the larval catch. The majority of larval fishes caught were in the postflexion stage of development, although some early juveniles were also caught. Body lengths of fish larvae ranged between 2 and 28 mm, with the majority of larvae at the recruitment size for the species. A high proportion of the fish species caught were estuary-dependent. Estuary-dependent marine fish larvae (categories I, II and IV) comprised 68% of total catch by species and 98% by number of individuals. Exclusively marine species (category III) were encountered in low numbers in the surf. The present study provides evidence for continuity in temperate South African surf zones in terms of domination by estuary-dependent larvae and reasons for this pattern are discussed.

Management of Fishery Resources in Yangtze River Estuary

OpenAIRE

Li, Meiling; Huang, Shuolin

2009-01-01

We introduce the fish fauna composition and main commercial fishes in Yangtze River estuary. We also analyze the current situation of resources and environment in Yangtze River estuary as well as the influential factors. Finally, related countermeasures are put forward on how to protect and use the fishery resources in Yangtze River.

Estuary fish data - Juvenile salmon in migratory corridors of lower Columbia River estuary

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Sampling juvenile salmon and associated fishes in open waters of the lower Columbia River estuary. Field work includes bi-weekly sampling during the spring...

Plankton composition in two estuaries of the Konkan coast during premonsoon season

Digital Repository Service at National Institute of Oceanography (India)

Achuthankutty, C.T.; Nair, S.R.S.; Devassy, V.P.; Nair, V.R.

abundant at the mouth region. Zooplankton biomass was relatively high in the Kajvi Estuary and all the major groups occurred in high density throughout this estuary. In the Shastri Estuary, the zooplankton biomass was relatively lower and all the major...

Photolysis of 2,4,6-trinitrotoluene in seawater and estuary water: Impact of pH, temperature, salinity, and dissolved organic matter

International Nuclear Information System (INIS)

Luning Prak, Dianne J.; Breuer, James E.T.; Rios, Evelyn A.; Jedlicka, Erin E.; O'Sullivan, Daniel W.

2017-01-01

The influence of salinity, pH, temperature, and dissolved organic matter on the photolysis rate of 2,4,6-trinitrotoluene (TNT) in marine, estuary, and laboratory-prepared waters was studied using a Suntest CPS +® solar simulator equipped with optical filters. TNT degradation rates were determined using HPLC analysis, and products were identified using LC/MS. Minimal or no TNT photolysis occurred under a 395-nm long pass filter, but under a 295-nm filter, first-order TNT degradation rate constants and apparent quantum yields increased with increasing salinity in both natural and artificial seawater. TNT rate constants increased slightly with increasing temperature (10 to 32 °C) but did not change significantly with pH (6.4 to 8.1). The addition of dissolved organic matter (up to 5 mg/L) to ultrapure water, artificial seawater, and natural seawater increased the TNT photolysis rate constant. Products formed by TNT photolysis in natural seawater were determined to be 2,4,6-trinitrobenzaldehyde, 1,3,5-trinitrobenzene, 2,4,6-trinitrobenzoic acid, and 2-amino-4,6-dinitrobenzoic acid. - Highlights: • 2,4,6-trinitrotoluene (TNT) was photolyzed in marine, estuary, & laboratory waters. • TNT photolysis rates increased with increasing salinity & dissolved organic matter. • Temperature and pH had minimal impact on TNT photolysis in marine waters. • In seawater, TNT photolysis produced 1,3,5-trinitrobenzene & trinitrobenzaldehyde. • Polar products were 2,4,6-trinobenzoic acid & 2-amino-4,6-dinitrobenzoic acid.

Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

Energy Technology Data Exchange (ETDEWEB)

Musenze, Ronald S.; Werner, Ursula [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); Grinham, Alistair [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); School of Civil Engineering, the University of Queensland, Brisbane, Qld 4072 (Australia); Udy, James [Healthy Waterways Ltd, P.O. Box 13086, George Street, Brisbane, Qld 4003 (Australia); Yuan, Zhiguo, E-mail: z.yuan@awmc.uq.edu.au [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia)

2014-02-01

Methane (CH{sub 4}) and nitrous oxide (N{sub 2}O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH{sub 4} and N{sub 2}O all-year-round. Dissolved N{sub 2}O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH{sub 4} concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH{sub 4} and N{sub 2}O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N{sub 2}O saturation significantly increased with NO{sub x} concentrations (r{sup 2} = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N{sub 2}O m{sup −2} d{sup −1} and 0.3 to 27.9 mg CH{sub 4} m{sup −2} d{sup −1}. Total emissions (CO{sub 2}-e) were N{sub 2}O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that

Elevational dependence of projected hydrologic changes in the San Francisco Estuary and watershed

Science.gov (United States)

Knowles, N.; Cayan, D.R.

2004-01-01

California's primary hydrologic system, the San Francisco Estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Previous work has shown that a projected warming would result in a reduction of snowpack storage leading to higher winter and lower spring-summer streamflows and increased spring-summer salinities in the estuary. The present work shows that these hydrologic changes exhibit a strong dependence on elevation, with the greatest loss of snowpack volume in the 1300-2700 m elevation range. Exploiting hydrologic and estuarine modeling capabilities to trace water as it moves through the system reveals that the shift of water in mid-elevations of the Sacramento river basin from snowmelt to rainfall runoff is the dominant cause of projected changes in estuarine inflows and salinity. Additionally, although spring-summer losses of estuarine inflows are balanced by winter gains, the losses have a stronger influence on salinity since longer spring-summer residence times allow the inflow changes to accumulate in the estuary. The changes in inflows sourced in the Sacramento River basin in approximately the 1300-2200 m elevation range thereby lead to a net increase in estuarine salinity under the projected warming. Such changes would impact ecosystems throughout the watershed and threaten to contaminate much of California's freshwater supply.

78 FR 46332 - Proposed Information Collection Request; Comment Request; National Estuary Program

Science.gov (United States)

2013-07-31

... Request; Comment Request; National Estuary Program AGENCY: Environmental Protection Agency (EPA). ACTION... request (ICR), ``National Estuary Program'' (EPA ICR No. 1500.08, OMB Control No. 2040-0138 to the Office... comments to OMB. Abstract: The National Estuary Program (NEP) involves collecting information from the...

Benthic macrofaunal dynamics and environmental stress across a salt wedge Mediterranean estuary.

Science.gov (United States)

Nebra, Alfonso; Alcaraz, Carles; Caiola, Nuno; Muñoz-Camarillo, Gloria; Ibáñez, Carles

2016-06-01

The spatial distribution of benthic macroinvertebrate community in relation to environmental factors was studied along the Ebro Estuary (NE Iberian Peninsula), a salt wedge Mediterranean estuary. Both ordination methods and generalized additive models were performed to identify the different benthic assemblages and their relationship to abiotic factors. Our results showed a strong relationship between macrofaunal assemblages and the predominant environmental gradients (e.g. salinity); thus revealing spatial differences in their structure and composition. Two different stretches were identified, namely the upper (UE) and the lower Ebro Estuary (LE). UE showed riverine characteristics and hence was colonized by a freshwater community; whereas LE was influenced by marine intrusion and sustained a complex marine-origin community. However, within each stretch, water and sediment characteristics played an important role in explaining species composition differences among sampling stations. Moreover, outcomes suggested a total species replacement pattern, instead of the nestedness pattern usually associated with well-mixed temperate estuaries. The sharp species turnover together with the estuarine stratification point out that the Ebro Estuary is working, in terms of ecological boundaries, under an ecotone model. Finally, despite obvious differences with well mixed estuaries (i.e. lack of tidal influence, stratification and species turnover), the Ebro Estuary shares important ecological attributes with well-mixed temperate estuaries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distribuição espacial de ferro, cobre e chumbo em sedimentos de manguezal em um gradiente de degradação na Baía de Guanabara (Estado do Rio de Janeiro Spatial distribution of iron, copper and lead in mangrove sediments in a degradation gradient in Guanabara Bay (Rio de Janeiro State

Directory of Open Access Journals (Sweden)

Anderson C. Borges

2007-02-01

Full Text Available Iron, copper and lead distribution was evaluated in sediment cores from a disturbed mangrove area in Guanabara Bay: a core from a seaward site where mangrove vegetation was removed ~20 yr before sampling (MD; a core from an intermediate site with dead vegetation, apparently due to insect attack (MP, and a core from a landward site with living vegetation (MV. Metal concentrations showed increasing values seaward while organic matter content showed an inverse trend, displaying a negative correlation with metals. This unusual correlation indicates opposite sources, since metals come from the bay and the main OM origin is probably degraded mangrove vegetation. Plant cover loss seems to be a critical factor affecting metal accumulation, particularly due to changes in OM input.

Nutrient budgets for large Chinese estuaries

Directory of Open Access Journals (Sweden)

S. M. Liu

2009-10-01

Full Text Available Chinese rivers deliver about 5–10% of global freshwater input and 15–20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN and depleted in dissolved inorganic phosphate (PO₄³⁻ with very high DIN: PO₄³⁻ concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3–4 times higher than those in the winter with the exception of NH₄⁺. The flux of NH₄⁺ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ~4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea. This suggests that land-derived nutrients are largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and

Variability in stratification and flushing times of the Gautami-Godavari estuary, India

Digital Repository Service at National Institute of Oceanography (India)

Sridevi, B.; Sarma, V.V.S.S.; Murty, T.V.R.; Sadhuram, Y.; Reddy, N.P.C.; Vijaykumar, K.; Raju, N.S.N.; JawaharKumar, CH.; Raju, Y.S.N.; Luis, R.; Kumar, M.D.; Prasad, K.V.S.R.

–Godavari estuary (G–GE) during spring and neap tide periods covering entire spectrum of discharge over a distance of 36 km from the mouth. The bathymetry of the estuary was recently changed due to dredging of ~20 km of the estuary from the mouth for transportation...

Functional diversity of fish in estuaries at a global extent

Directory of Open Access Journals (Sweden)

Rita P Vasconcelos

2015-10-01

Full Text Available Biodiversity is currently viewed as a framework encompassing multiple facets of the variety of life, including taxonomic and functional aspects. Species richness and composition of fish assemblages in estuaries is defined by global to local processes acting on community colonization. The present study further investigates how biodiversity of fish assemblages varies among estuaries globally, by simultaneously analysing taxonomic and functional richness and diversity of assemblages. A comprehensive worldwide database was compiled on the fish assemblage composition and environmental characteristics of estuaries. In addition, functional attributes of the fish species were characterized such as body size, habitat use and trophic ecology. We investigated the relationship between taxonomic and functional aspects of biodiversity, i.e. the match or mismatch between the two. We also explored how functional diversity of fish assemblages varied among estuaries globally and related to environmental features of estuaries, i.e. historic and contemporary, global and local constraints. The results are explored in the context of ecosystem functioning and resilience, and outcomes relevant to assist in prioritizing conservation efforts are highlighted.

Plastic pollution in five urban estuaries of KwaZulu-Natal, South Africa.

Science.gov (United States)

Naidoo, Trishan; Glassom, David; Smit, Albertus J

2015-12-15

Monitoring plastic concentrations in estuaries is vital in assessing the magnitude of terrestrial inputs to oceanic environments. Data on plastics ≤ 5 mm in estuaries are scant. This study determined microplastic levels within five estuaries along the Durban coastline and on intervening beaches. Plastics were isolated from estuarine sediment, beach sediment and the surface water of each estuary and characterised. Sediment at the Bayhead area of Durban harbour had the highest average plastic concentrations (745.4 ± 129.7 particles per 500 ml) and an attenuating concentration trend away from the city centre was found. Prevailing south to north longshore drift was hypothesised to result in plastic accumulation on the northern shores of beaches with estuarine effluents, however, this was not found. Fragments composed the largest percent of plastics (59%) found in Bayhead, whereas fibres dominated other estuaries with proportions ranging from 38% of total plastics in the uMgeni estuary to 66% in the Mdloti. Copyright © 2015 Elsevier Ltd. All rights reserved.

Relation between tidal damping and wave celerity in estuaries

NARCIS (Netherlands)

Savenije, H.H.G.; Veling, E.J.M.

2005-01-01

Observations in estuaries indicate that an amplified tidal wave moves considerably faster than is indicated by the classical equation for wave propagation. Similarly, the celerity of propagation is lower if the tidal wave is damped. This phenomenon is clearly observed in the Schelde estuary (located

Sediment toxicity testing with the amphipod Ampelisca abdita in Calcasieu Estuary, Louisiana

Science.gov (United States)

Redmond, M.S.; Crocker, P.A.; McKenna, K.M.; Petrocelli, E.A.; Scott, K.J.; Demas, C.R.

1996-01-01

Discharges from chemical and petrochemical manufacturing facilities have contaminated portions of Louisiana's Calcasieu River estuary with a variety of organic and inorganic contaminants. As part of a special study, sediment toxicity testing was conducted to assess potential impact to the benthic community. Ten-day flow-through sediment toxicity tests with the amphipod Ampelisca abdita revealed significant toxicity at 68% (26 of 38) of the stations tested. A. abdita mortality was highest in the effluent-dominated bayous, which are tributaries to the Calcasieu River. Mortality was correlated with total heavy metal and total organic compound concentrations in the sediments. Ancillary experiments showed that sediment interstitial water salinity as low as 2.5 o/o-o did not significantly affect A. abdita's, response in the flow-through system; sediment storage for 7 weeks at 4??C did not significantly affect toxicity. Sediment toxicity to A. abdita was more prevalent than receiving water toxicity using three short-term chronic bioassays. Results suggest that toxicity testing using this amphipod is a valuable tool when assessing sediments containing complex contaminant mixtures and for assessing effects of pollutant loading over time. In conjunction with chemical analyses, the testing indicated that the effluent-dominated, brackish bayous (Bayou d'Inde and Bayou Verdine) were the portions of the estuary most impacted by toxicity.

76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

Science.gov (United States)

2011-02-14

... and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and Steelhead AGENCY.... ACTION: Notice of availability; recovery plan module for Columbia River estuary salmon and steelhead... Plan Module for Salmon and Steelhead (Estuary Module). The Estuary Module addresses the estuary...

Development of an integrative approach for the characterization of environmental risk on marine transition ecosystems: the Sado estuary as a case study

Directory of Open Access Journals (Sweden)

Filipa Maria Pereira

2014-05-01

Full Text Available Estuaries and transitional waters are important ecosystems from which organisms and humans are dependent on for survival. They are important as nursery areas and shelter for many aquatic organisms, from which humans and their economical activities are dependent on. Humans also depend on estuaries for other reasons such as tourism, heavy industry, aquaculture and shipping. The degradation of estuarine environmental quality implies ecologic, economic and social prejudice, so it is important to evaluate the state of the environment to assist management. The Sado estuary (SW Portugal is considered moderately contaminated. The area is impacted by diverse human activities, from shipping, industry, urbanism and even mariculture and agriculture activities. Because Sado estuary is very important for human and ecological reasons, many studies were conducted by several researchers in past few years, albeit scattered. As such, there was a need to integrate the information hitherto produced, in order to obtain a clear and complete image of the overall environmental quality status of the area, to assist future management plans and decision-making. For the purpose, a geographical information system (GIS was created from sediment contamination and biomarker data collected from a decade-long time-series of publications. Five distinct areas were identified from the Sado estuary: a clean area plus four contaminated areas characterized by distinct sediment contamination patterns, related to different pollution hot spots and diffuse contamination sources. Also, in spite of the multiple biological traits under survey, the biomarker data (from several organisms are in general agreement with the environmental contamination georeferencing information. Through this evaluation, the main anthropogenic sources of pollutants were identified, namely, the shipyard area and adjacent industrial belt, followed by urban and agricultural inputs into the estuary. From the data it is

Contamination and restoration of an estuary affected by phosphogypsum releases

Energy Technology Data Exchange (ETDEWEB)

Villa, M., E-mail: mvilla@us.es [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mosqueda, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Hurtado, S. [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mantero, J.; Manjon, G. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain); Perianez, R. [E.U.I.T.A., Universidad de Sevilla, Departamento de Fisica Aplicada III, Carretera de Utrera, Km. 1, 41013 Sevilla (Spain); Vaca, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Garcia-Tenorio, R. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain)

2009-12-15

The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides {sup 226}Ra and {sup 210}Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of {sup 210}Pb and {sup 226}Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for {sup 226}Ra and {sup 210}Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary

The importance of the river-estuary interface (REI) zone in estuaries

African Journals Online (AJOL)

drinie

2002-07-03

Jul 3, 2002 ... A multidisciplinary and multi-institutional research programme studied the influence of river flow rate on salinity distribution and response of the ... alia, the state of the mouth influences the extent of water exchange with the sea, vertical and ... The Kariega Estuary is a marine dominated system with very little.

Columbia Estuary Ecosystem Restoration Program. 2012 Synthesis Memorandum

Science.gov (United States)

2013-01-01

LCFRB Lower Columbia Fish Recovery Board LCRE lower Columbia River and estuary LCREP Lower Columbia River Estuary Partnership LWD large woody debris...hydraulic reconnections, channel creation, large woody debris [ LWD ] placement) have restored a total of 3152 acres since 2001. If land acquisition...fencing, invasive plant removal, native replanting. Mirror Lake 208 Culvert replaced with a bridge, riparian restoration, LWD enhancement, culvert

NEW DATA ABOUT MACROZOOBENTHOS OF BEYSUGSKY ESTUARY (SEA OF AZOV

Directory of Open Access Journals (Sweden)

N. I. Bulysheva

2013-01-01

Full Text Available Abstract. Aim. Beysugsky Estuary is one of the biggest estuaries of the Azov-Kuban’ lowland. Like the other water bodies in the South of Russia, this one is subject to strong anthropogenic load: detachment of the freshwater part for establishing the Beysug spawning area; regulation of the flow of the rivers feeding the estuary; destruction of the Yasenskaya spit and narrowing of the Bugaz mouth; disorganized tourism. The ongoing reformation of the ecosystem makes it necessary to carry out the analyses of the modern state of the biota of this water body and uncover reasons and regularities of its change.Location. Beysug Estuary of the Sea of Azov.Methods. Quantitative zoobenthos samples were taken with the Petersen dredger (sampling area 0,034 m2 from board of the inflatable “Zodiac” boat. Qualitative samples were taken in the coastal zone by hand and with the dredge. All the samples taken were washed through the bag made of mill sieve with mesh size 0,5 mm, and then were fixed in a plastic bucket by 4 % formaldehyde (quantitative samples or 70 % ethyl alcohol (qualitative samples. Taking and processing of samples were carried out in field and laboratory environment using common methods. 22 samples at 7 stations were taken in total.Results. Macrozoobenthos was presented by 14 invertebrate species. Estuarine fauna is the depleted version of the euryhaline one of the Sea of Azov with Holocene relic macrophyte-dwelling elements. Biodiversity and quantitative characters of the estuarine communities decrease from west to east. Pelophylic detritophages predominated in the benthic communities of the estuary. The results of this research are meant to be used for uncovering historical ways of forming of benthic fauna and clearing up the dependence of community structure on the seawater influence, freshwater flow, regulation of freshwater and seawater sources, nature of changing of faunas at salinization of estuaries connected with the sea and the

Has the rapidly expanding invasive dwarf eelgrass Zostera japonica in Yaquina estuary, Oregon impacted the distribution of native eelgrass Zostera marina – a critical intertidal habitat?

Science.gov (United States)

Native eelgrass, Zostera marina, occupies a significant portion of marine-dominated intertidal and near-subtidal sectors of many coastal estuaries. In recent decades an invasive congener, Z. japonica, has become established in many Pacific Northwest estuaries. We measured the h...

Pollution induced tidal variability in water quality of Mahim Estuary

Digital Repository Service at National Institute of Oceanography (India)

Zingde, M.D.; Sabnis, M.M.

Variability of water quality due to release of wastewater in Mahim Estuary (Maharashtra, India) and associated nearshore waters is discussed. The mixing of low salinity contaminated estuary water with high salinity bay water was considerably...

Natural forcings on a transformed territory overshoot thresholds of primary productivity in the Guadalquivir estuary

Science.gov (United States)

Ruiz, J.; Macías, D.; Navarro, G.

2017-09-01

A three year-long quasi continuum sampling dataset on the Guadalquivir estuary water quality was used to assess the role of light availability on its biological production. We found that inorganic nutrients within the estuary are very high (with mean values for inorganic nitrogen and phosphorous of 285 and 2.4 μM respectively) while phytoplankton biomass remains low most of the time (with a mean value of 2.6 mg/m3). A strong relationship between phytoplankton biomass and water turbidity was found indicating that, indeed, light availability is the major constraint of primary production in this system. Most of the time this limitation of primary production is not associated to enhanced turbidity connected to fresh water inputs. Instead, our data indicate that, independently of freshwater inputs, the photosynthesis is restricted by tidal forcings enhancing turbidity in an estuary that has been highly modified. Our results match with classical theories on the functioning of well-mixed, estuarine ecosystems as well as with recent modeling exercises. We also discuss the potential impacts of this particular characteristic of some estuarine systems for their management and regulatory control.

Composition and structure of the larval fish community related to environmental parameters in a tropical estuary impacted by climate change

Science.gov (United States)

Sloterdijk, Hans; Brehmer, Patrice; Sadio, Oumar; Müller, Hanno; Döring, Julian; Ekau, Werner

2017-10-01

Mangrove ecosystems have long been considered essential habitats and are commonly viewed and referred to as "nursery areas". They are highly sensitive to climate change, and environmental transformations in these ecosystems are expected. The Sine Saloum estuary is a case of a system affected by global climate change where reduced precipitation and temperature increase have resulted in an inversion of the salinity gradient. Within the estuary, the composition and structure of the larval fish community related to environmental parameters were investigated using neuston and ring trawl nets. Larval fishes were sampled at 16 stations distributed along a salinity and distance-to-the-sea gradient during four field campaigns (November 2013, February, June, and August 2014) covering an annual cycle. This is the first study documenting the spatial and temporal assemblages of fish larvae in an inverse estuary. The total of 41 taxa representing 24 families and 34 genus identified in this study was lower than that of other tropical estuaries. Clupeidae spp. was the dominant taxon, accounting for 28.9% of the total number of fish larvae caught, followed by Gerreidae spp. (21.1%), Hyporamphus picarti (18.8%), Diplodus bellottii (8.9%), Hypleurochilus langi (4.8%), Mugilidae spp. (4.4%), and Gobiidae sp.1 (3.5%). A total of 20 taxa were recorded within the upper estuary region, whereas 29 and 37 taxa were observed in the middle and lower reaches, respectively. While larval fish were captured at all sites and during all seasons, abundances and richness decreased with increasing salinity. Larval fish assemblages also showed a clear vertical structure corresponding to three distinct water strata. Salinity, water temperature, and dissolved oxygen were the variables that best explained the spatial and temporal differences in larval fish assemblages. It is difficult to forecast the future situation for this system but so far, compared to other mangrove estuarine systems, we have

Pollutant Flux Estimation in an Estuary Comparison between Model and Field Measurements

Directory of Open Access Journals (Sweden)

Yen-Chang Chen

2014-08-01

Full Text Available This study proposes a framework for estimating pollutant flux in an estuary. An efficient method is applied to estimate the flux of pollutants in an estuary. A gauging station network in the Danshui River estuary is established to measure the data of water quality and discharge based on the efficient method. A boat mounted with an acoustic Doppler profiler (ADP traverses the river along a preselected path that is normal to the streamflow to measure the velocities, water depths and water quality for calculating pollutant flux. To know the characteristics of the estuary and to provide the basis for the pollutant flux estimation model, data of complete tidal cycles is collected. The discharge estimation model applies the maximum velocity and water level to estimate mean velocity and cross-sectional area, respectively. Thus, the pollutant flux of the estuary can be easily computed as the product of the mean velocity, cross-sectional area and pollutant concentration. The good agreement between the observed and estimated pollutant flux of the Danshui River estuary shows that the pollutant measured by the conventional and the efficient methods are not fundamentally different. The proposed method is cost-effective and reliable. It can be used to estimate pollutant flux in an estuary accurately and efficiently.

Trace elements and radionuclides in the Connecticut River and Amazon River estuary

International Nuclear Information System (INIS)

Dion, E.P.

1983-01-01

The Connecticut River, its estuary, and the Amazon River estuary were studied to elucidate some of the processes which control river water chemistry and the flux of elements to the sea. The approach taken was to identify inputs to the Connecticut River and to investigate geochemical processes which modify the dissolved load. The form and quantity of nuclides which are in turn supplied to the estuary are altered by processes unique to that transition zone to the ocean. The Connecticut River estuary was sampled on a seasonal basis to investigate the role of the estuary in controlling the flux of elements to the sea. The knowledge gained from the Connecticut River study was applied to the quantitatively more significant Amazon River estuary. There a variety of samples were analyzed to understand the processes controlling the single greatest flux of elements to the Atlantic Ocean. The results indicate that estimates of the total flux of nuclides to the oceans can best be calculated based on groundwater inputs. Unless significant repositories for nuclides exist in the river-estuarine system, the groundwater flux of dissolved nuclides is that which will eventually be delivered to the ocean despite the reactions which were shown to occur in both rivers and estuaries. 153 references, 63 figures, 28 tables

Nutrient input through submarine groundwater discharge in two major Chinese estuaries: the Pearl River Estuary and the Changjiang River Estuary

Science.gov (United States)

Liu, Jianan; Du, Jinzhou; Wu, Ying; Liu, Sumei

2018-04-01

In this study, we used a 224Ra mass balance model to evaluate the importance of submarine groundwater discharge (SGD) for the budgets of biogenic elements in two major Chinese estuaries: the Pearl River Estuary (PRE) and the Changjiang River Estuary (CRE). The apparent water age in the PRE was estimated to be 4.8 ± 1.1 days in the dry season and 1.8 ± 0.6 days in the wet season using a physical model based on the tidal prism. In the dry season, the water age in the CRE was estimated to be 11.7 ± 3.0 days using the 224Ra/223Ra activities ratios apparent age model. By applying the 224Ra mass balance model, we obtained calculations of the SGD flow in the PRE of (4.5-10) × 108 m3 d-1 (0.23-0.50 m3 m-2 d-1) and (1.2-2.7) × 108 m3 d-1 (0.06-0.14 m3 m-2 d-1) in the dry season and wet season, respectively, and the estimated SGD flux was (4.6-11) × 109 m3 d-1 (0.18-0.45 m3 m-2 d-1) in the dry season of the CRE. In comparison with the nutrient fluxes from the rivers, the SGD-derived nutrient fluxes may play a vital role in controlling the nutrient budgets and stoichiometry in the study areas. The large amount of dissolved inorganic nitrogen and phosphorus fluxes together with high N: P ratios into the PRE and CRE would potentially contribute to eutrophication and the occurrence of red tides along the adjacent waters.

Nutrient characterisation of river inflow into the estuaries of the ...

African Journals Online (AJOL)

Nutrient characterisation of river inflow into the estuaries of the Gouritz Water ... into the estuaries within the Gouritz Water Management Area (WMA) of South Africa. ... Long-term water quality monitoring data (dissolved inorganic nitrogen, i.e. ...

Country-wide assessment of estuary health: An approach for integrating pressures and ecosystem response in a data limited environment

CSIR Research Space (South Africa)

Van Niekerk, L

2013-09-01

Full Text Available zone (area) for every system. In addition, available data on pressures impacting estuaries on a national scale were collated. A desktop national health assessment, based on an Estuarine Health Index developed for South African ecological water...

Integration of remotely sensed data and hydrodynamic modeling into a GIS to assess the impacts of thermal effluent in an estuary

International Nuclear Information System (INIS)

Mustard, J.F.; Sen, A.; Swanson, C.; Mendelsohn, D.

1997-01-01

A project to assess the effects of thermal effluent from a electrical generating facility on an estuary is described. The project is designed to integrate remote sensing observations with in situ field data and a computer model system to provide continuous, estuary-wide predictions of the effluent plume location and configurations. Remote sensing data was acquired over the ebb tide cycle by an aircraft-mounted multi-channel imaging spectrometer. A ground truth field program measured water temperature on a series of transects during the overflights. Moored instruments continuously acquired data on currents, salinity, temperature and dissolved oxygen before, during and after the day of the overflight. A hydrodynamic model was used to predict the three-dimensional structure of the currents, temperature and salinity in the estuary. A Lagrangian particle-based trajectory model was used to predict the small scale surface features seen in the overflight images. Results indicate that such a system can provide useful data in support of analyses of thermal effects of the ecology of estuarine environments

Variation of phytoplankton community structure from the Pearl River estuary to South China Sea.

Science.gov (United States)

Jiang, Zhao-Yu; Wang, You-Shao; Cheng, Hao; Sun, Cui-Ci; Wu, Mei-Lin

2015-10-01

The Pearl River is located in the northern part of South China Sea. The environment of the Pearl River estuary (PRE) is significantly impacted by nutrients from anthropogenic activities. Along the anthropogenic pollution gradient from the PRE to South China Sea, the phylogenetic diversity and biomass of phytoplankton was examined in relation to physic-chemical variables. The richness of rbcL gene was higher in the open sea than the estuary, while the concentration of chlorophyll a (Chl a) was higher in the estuary than in the open sea. The cluster analysis of the sequences data resulted in seven phytoplankton community types and the dominant species of phytoplankton changed from Cryptophytes and Diatoms to Prymnesiophytes and Diatoms along the gradient. The community structure of phytoplankton was shaped by nutrients and salinity. The phytoplankton biomass was significantly positively affected by phosphorus, nitrite and ammonium (P < 0.01) but negatively by salinity (P < 0.05); the phytoplankton diversity was highly positively affected by salinity (P < 0.05) but negatively by silicate and nitrate (P < 0.01; P < 0.05, respectively). Anthropogenic activities played a critical role in the phytoplankton distribution and biomass of the study area. Further research is necessary to reveal the influence mechanism of environmental factors on the phytoplankton.

Macrobenthic community in the Douro estuary: relations with trace metals and natural sediment characteristics

International Nuclear Information System (INIS)

Mucha, A.P.; Vasconcelos, M.T.S.D.; Bordalo, A.A.

2003-01-01

This study used a novel approach to detect a clear signature of metal contamination and biological impacts in an estuary. - The relationship between macrobenthic community structure and natural characteristics of sediment and trace metal contamination were studied in the lower Douro estuary (Portugal, NW, Iberian Peninsula), using an innovative threefold approach (SQG, Sediment Quality Guidelines), metal normalization to Fe, and macrobenthic community structure. This study allowed detection of a clear signature of anthropogenic contamination, in terms of Zn, Cu, Pb, and Cr in the north bank of the estuary, which experiences high urban pressure. Using the SQG approach, metal concentrations above ERM (effects range--median) were observed only at one sampling station, but several stations had levels above ERL (effects range-low). The macrobenthic community had a low diversity, with only 19 species found in the entire estuarine area, dominated by opportunistic species. The granulometric distribution of the sediments (estimated from the combination of organic matter, Fe and Al) seemed to be the major structuring factor for the communities, establishing the natural macrobenthic distribution pattern. The metals (Zn, Cu, Pb, and Cr) seemed to act as a disturbing factor over the natural distribution, with deleterious consequences for the macrobenthic communities

Resumos dos Trabalhos Apresentados em Painéis no Workshop Baía de Guanabara, IGEO/UFRJ - 2002

Directory of Open Access Journals (Sweden)

2003-01-01

Full Text Available 139 Anuário do Instituto de Geociências - UFRJ Volume 26 / 2003 Avaliação dos Efeitos Ambientais e Ecológicos Referentes ao Acidente Ocorrido no Oleoduto Pe-II (Reduc-Petrobrás na Baía de Guanabara - RJ. Patrícia P. B. Eichler (Laboratório de Ciências Marinha/UNISUL1, Beatriz B. Eichler (Instituto Oceanográfico/IOUSP, Felipe M. Pimenta (Labotratório de Hidráulica Marítima/ UFSC, Patrícia B. P. K. Cardoso (IOUSP, Evelyn da Rocha Mendes Pereira (IOUSP. 1Rua: João Pessoa, 100, 88790-100, Laguna, SC, peichler@ceres.io.usp.br Em janeiro de 2000, o acidente no oleoduto PE-II, derramou 1292 m3 de óleo combustível (MF380 ao norte da ilha do Governador. Para avaliar os danos ambientais e ecológicos ocorridos em função do acidente foram coletadas 26 amostras de sedimento no inverno/2000 (6 a 17/07/2000, 6 meses após o acidente e repetida a mesma malha amostral no verão/2001 (1 a 15/02/2001, 1 ano após o acidente. Com base nos mapas de contorno de freqüência relativa das espécies de foraminíferos e teores de pH e oxigênio foi possível avaliar o grau de hipoxia (O2<2mg/l e de acidez no sedimento correlacionando-os à dinâmica populacional desses microrganismos. No inverno, próximo a REDUC, observa-se o mais baixo valor de pH (1,81, indicando acidez do sedimento devido ao aumento de H2S liberado por ocasião do derramamento de óleo. Com relação aos teores de oxigênio no inverno e no verão, a entrada da baía é o ambiente mais oxigenado. Os locais menos oxigenados estão localizados na parte nordeste, próxima a APA de Guapimirim, e na parte noroeste, próximo à REDUC. No inverno, observa-se que o teor de oxigênio na coluna de água próximo à REDUC apresenta valor muito baixo, indicando que os processos químicos envolvidos na quebra do óleo além de diminuir o pH, consumiram também, o teor de oxigênio da água. No verão, os valores obtidos para o oxigênio de fundo nas estações da região central e nordeste de

Plutonium in Atlantic coastal estuaries in the southeastern United States of America

International Nuclear Information System (INIS)

Hayes, D.W.; LeRoy, J.H.; Cross, F.A.

1976-01-01

A survey was made to begin to provide baseline information on the plutonium distribution of representative estuarine and coastal areas of the southeastern United States of America. Sediments and marsh grass (Spartina) were collected and analysed from three locations within a tidal marsh. In the three estuaries (Savannah, Neuse and Newport) the suspended particulate matter (1μm and greater) was filtered from waters with different salinities and the plutonium content of the particulates determined. The Savannah river estuary, in addition to fall-out plutonium, has received up to 0.3Ci of plutonium from the Savannah River Plant (SRP) of the US Energy Research and Development Administration. The SRP plutonium has a variable isotopic composition that can influence plutonium isotopic ratios in the estuarine system. The other estuaries do not have nuclear installations upstream. Plutonium contents in surface marsh sediment from the Savannah River estuary are lower than those found in nearby bay sediments. In fact, total plutonium concentrations of sediments showed increases from the upper to lower portions of the estuary; however, higher contributions of 238 Pu in the upper portions indicate that releases from the Savannah River Plant do contribute plutonium to the Savannah river estuary. Plutonium concentrations in Spartina were less than 10fCi/g dry weight but are higher than plutonium contents of terrestrial plants ( 238 Pu to the total plutonium activities in the sediment and the Spartina. Plutonium concentrations were about three times higher in the Newport river estuary than in the Neuse and Savannah river estuaries. (author)

[Spatiotemporal dynamic fuzzy evaluation of wetland environmental pollution risk in Dayang estuary of Liaoning Province, Northeast China based on remote sensing].

Science.gov (United States)

Sun, Yong-Guang; Zhao, Dong-Zhi; Zhang, Feng-Shou; Wei, Bao-Quan; Chu, Jia-Lan; Su, Xiu

2012-11-01

Based on the aerial image data of Dayang estuary in 2008, and by virtue of Analytic Hierarchy Process (AHP) , remote sensing technology, and GIS spatial analysis, a spatiotemporal evaluation was made on the comprehensive level of wetland environmental pollution risk in Dayang estuary, with the impacts of typical human activities on the dynamic variation of this comprehensive level discussed. From 1958 to 2008, the comprehensive level of the environmental pollution risk in study area presented an increasing trend. Spatially, this comprehensive level declined from land to ocean, and showed a zonal distribution. Tourism development activities unlikely led to the increase of the comprehensive level, while human inhabitation, transportation, and aquaculture would exacerbate the risk of environmental pollution. This study could provide reference for the sea area use planning, ecological function planning, and pollutants control of estuary region.

Upstream Freshwater and Terrestrial Sources Are Differentially Reflected in the Bacterial Community Structure along a Small Arctic River and Its Estuary

DEFF Research Database (Denmark)

Hauptmann, Aviaja Zenia Edna Lyberth; Markussen, Thor N; Stibal, Marek

2016-01-01

of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N). Samples were taken in August when there is maximum precipitation......Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact...... and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity...

Human Health Impact of Natural and Artificial Radioactivity Levels in the Sediments and Fish of Bonny Estuary, Niger Delta, Nigeria

Directory of Open Access Journals (Sweden)

Bolaji B. Babatunde

2015-11-01

Full Text Available There is widespread contamination of the environment of the Niger Delta, which may include enhanced background levels of naturally occurring radioactive materials (NORM due to oil production and rapid urbanization activities. Sediments and seafood from the Bonny estuary, Niger Delta, were collected for the purpose of determining baseline data on artificial and natural radioactivity and estimation of effective doses for the public due to ingestion of seafood from the study area. The highest and lowest activity concentrations were reported for 40K and 137Cs in both sediments and fish samples of the Bonny estuary. There was some evidence of spatial variability in the 40K and 137Cs data, with the latter being the likely result of dredging. Other radionuclides were not significantly different between sites impacted by industrial activities or not. Activity of radionuclides measured in the sediments of the study area were higher than reported elsewhere in the Niger Delta and Nigeria and higher than reported global averages by UNSCEAR. The total highest activity concentration in all fish species of gamma emitting radionuclides was observed for 40K, followed by 238U, 232Th and 226Ra, respectively, while 137Cs had the lowest activity concentration. However, 210Po activities were the most important in terms of dose contribution. Consumption of molluscs at typical rates could result in doses exceeding 1 mSv·y−1. Although this baseline data may not be conclusive on prevailing trends in radioactivity in the study area, higher consumption rates of the species studied may have public health consequences due to effects of low dose ionising radiation.

Potential impact of predicted sea level rise on carbon sink function of mangrove ecosystems with special reference to Negombo estuary, Sri Lanka

Science.gov (United States)

Perera, K. A. R. S.; De Silva, K. H. W. L.; Amarasinghe, M. D.

2018-02-01

Unique location in the land-sea interface makes mangrove ecosystems most vulnerable to the impacts of predicted sea level rise due to increasing anthropogenic CO2 emissions. Among others, carbon sink function of these tropical ecosystems that contribute to reduce rising atmospheric CO2 and temperature, could potentially be affected most. Present study was undertaken to explore the extent of impact of the predicted sea level rise for the region on total organic carbon (TOC) pools of the mangrove ecosystems in Negombo estuary located on the west coast of Sri Lanka. Extents of the coastal inundations under minimum (0.09 m) and maximum (0.88 m) sea level rise scenarios of IPCC for 2100 and an intermediate level of 0.48 m were determined with GIS tools. Estimated total capacity of organic carbon retention by these mangrove areas was 499.45 Mg C ha- 1 of which 84% (418.98 Mg C ha- 1) sequestered in the mangrove soil and 16% (80.56 Mg C ha- 1) in the vegetation. Total extent of land area potentially affected by inundation under lowest sea level rise scenario was 218.9 ha, while it was 476.2 ha under intermediate rise and 696.0 ha with the predicted maximum sea level rise. Estimated rate of loss of carbon sink function due to inundation by the sea level rise of 0.09 m is 6.30 Mg C ha- 1 y- 1 while the intermediate sea level rise indicated a loss of 9.92 Mg C ha- 1 y- 1 and under maximum sea level rise scenario, this loss further increases up to 11.32 Mg C ha- 1 y- 1. Adaptation of mangrove plants to withstand inundation and landward migration along with escalated photosynthetic rates, augmented by changing rainfall patterns and availability of nutrients may contribute to reduce the rate of loss of carbon sink function of these mangrove ecosystems. Predictions over change in carbon sequestration function of mangroves in Negombo estuary reveals that it is not only affected by oceanographic and hydrological alterations associated with sea level rise but also by anthropogenic

Discontinuous Galerkin modeling of the Columbia River's coupled estuary-plume dynamics

Science.gov (United States)

Vallaeys, Valentin; Kärnä, Tuomas; Delandmeter, Philippe; Lambrechts, Jonathan; Baptista, António M.; Deleersnijder, Eric; Hanert, Emmanuel

2018-04-01

The Columbia River (CR) estuary is characterized by high river discharge and strong tides that generate high velocity flows and sharp density gradients. Its dynamics strongly affects the coastal ocean circulation. Tidal straining in turn modulates the stratification in the estuary. Simulating the hydrodynamics of the CR estuary and plume therefore requires a multi-scale model as both shelf and estuarine circulations are coupled. Such a model has to keep numerical dissipation as low as possible in order to correctly represent the plume propagation and the salinity intrusion in the estuary. Here, we show that the 3D baroclinic discontinuous Galerkin finite element model SLIM 3D is able to reproduce the main features of the CR estuary-to-ocean continuum. We introduce new vertical discretization and mode splitting that allow us to model a region characterized by complex bathymetry and sharp density and velocity gradients. Our model takes into account the major forcings, i.e. tides, surface wind stress and river discharge, on a single multi-scale grid. The simulation period covers the end of spring-early summer of 2006, a period of high river flow and strong changes in the wind regime. SLIM 3D is validated with in-situ data on the shelf and at multiple locations in the estuary and compared with an operational implementation of SELFE. The model skill in the estuary and on the shelf indicate that SLIM 3D is able to reproduce the key processes driving the river plume dynamics, such as the occurrence of bidirectional plumes or reversals of the inner shelf coastal currents.

Fish abundance and distribution in the Gamtoos estuary with notes ...

African Journals Online (AJOL)

favourably with other larger systems like the Sundays, Bashee and Kei estuaries. .... as well as the use of pesticides undoubtedly affects water quality in the ... Methods. Catch per unit effort (CPUE) of fish in the Gamtoos estuary was obtained ...

A comparative study of Northern Ireland's estuaries based on the results of beam trawl fish surveys

Science.gov (United States)

Harrison, Trevor D.; Armour, Neil D.; McNeill, Michael T.; Moorehead, Peter W.

2017-11-01

The fish communities of Northern Ireland's estuaries were described and compared using data collected with a modified beam trawl over a six year period from 2009 to 2014. Multivariate analyses identified four estuary groups based on variations in their physico-chemical attributes. These groups broadly corresponded with the distribution and variation of estuary geomorphic types identified around the Irish coast. The dominant fish species captured were also among the main species reported in other North East Atlantic estuaries. A significant link between the estuary types and their fish communities was found; each estuary group contained a somewhat distinctive fish community. The fish communities also showed a significant relationship with the physico-chemical characteristics of the estuaries. Differences in fish species composition are attributed to habitat and environmental preferences of key estuary-associated species.

Field observations of hypersaline runoff through a shallow estuary

Science.gov (United States)

Hosseini, Seyed Taleb; Siadatmousavi, Seyed Mostafa

2018-03-01

This study investigates a rare situation at the Mond River Estuary in the Persian Gulf, in which the classical estuarine density gradient coincides with hypersaline runoff entering from saline soils upstream of the estuary after severe precipitation. This builds a unique estuarine setting, where two salt water masses, one originating from the coastal ocean and the other being discharged from upstream confine a range of almost freshwater in the middle of estuary. This "freshwater lens estuary" (FLE) situation includes two saltwater sources with opposing senses of estuarine circulation. Therefore, the tidal damping by the strong river flood can occur, especially during neap tide when high Unsteadiness number (∼0.04) signified ebb oriented condition which was induced by straining residual lateral circulation near the FLE mouth. Transition from well-mixed to weak strain induced periodic stratification regimes indicated the importance of the spring-neap tidal variations. Close to the mouth, a 13.66-day periodic tidal asymmetry from the triad K1-O1-M2 (ebb-dominance during spring tide and flood-dominance in neap tide) was overcome by higher harmonics.

Has the rapidly expanding invasive dwarf eelgrass Zostera japonica in Yaquina estuary, Oregon impacted the distribution of native eelgrass Zostera marina – a critical intertidal habitat? - CERF

Science.gov (United States)

Native eelgrass, Zostera marina, occupies a significant portion of marine-dominated intertidal and near-subtidal sectors of many coastal estuaries. In recent decades an invasive congener, Z. japonica, has become established in many Pacific Northwest estuaries. We measured the h...

Avaliação da Poluição Antrópica Usando Padrão de Distribuição deEspécies de Foraminíferos Provenientes de Testemunhos da Baía de Guanabara, RJ.

OpenAIRE

Brígida Orioli Figueira; Claudia Gutterres Vilela; José Antônio Baptista Neto

2007-01-01

This work presents a study of benthic foraminifera recovered from three cores collected near the Paquetá island, in the Guanabara bay, Rio de Janeiro, southeastern Brazil. The cores have different sizes and were subsampled in centimetric intervals. The recovered benthic foraminiferal assemblages were thoroughly identified, in order to carry out an ecological study towards reconstructing the environmental evolution of the studied area during the recent historical period and assessing the respo...

33 CFR 165.1190 - Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA.

Science.gov (United States)

2010-07-01

..., Oakland Estuary, Alameda, CA. 165.1190 Section 165.1190 Navigation and Navigable Waters COAST GUARD... § 165.1190 Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. (a) Location. The following area is a security zone: All navigable waters of the Oakland Estuary, California, from the surface to...

A Palinologia como Ferramenta no Diagnóstico e Monitoramento Ambiental da Baía de Guanabara e Regiões Adjacentes, Rio de Janeiro, Brasil

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Ortrud Monika Barth

2003-01-01

Full Text Available Palynology is a tool in retrospective studies related to climatic and environmental changes and to the human influence on the landscape in historical times. Pollen analyses of cores obtained from the Baía de Sepetiba , from lakes of the northern region of the state of Rio de Janeiro and recently of sediments from the basin of the rio Guandu, from the praia Vermelha/Urca beach and from the bottom of the Baía de Guanabara were realized. Drier and wetter climatic periods could be detected corresponding to a variable development of the rain forest, the semideciduous forest, the vegetation of “restinga”, savannas and wetlands. Human activities and changes of the environment related to changes of the vegetation in historical times were confirmed.

Historical changes in the Columbia River Estuary

Science.gov (United States)

Sherwood, Christopher R.; Jay, David A.; Bradford Harvey, R.; Hamilton, Peter; Simenstad, Charles A.

Historical changes in the hydrology, sedimentology, and physical oceanography of the Columbia River Estuary have been evaluated with a combination of statistical, cartographic, and numerical-modelling techniques. Comparison of data digitized from US Coast and Geodetic Survey bathymetric surveys conducted in the periods 1867-1875, 1926-1937, and 1949-1958 reveals that large changes in the morphology of the estuary have been caused by navigational improvements (jetties, dredged channels, and pile dikes) and by the diking and filling of much of the wetland area. Lesser changes are attributable to natural shoaling and erosion. There has been roughly a 15% decrease in tidal prism and a net accumulation of about 68 × 10 6m 3 of sediment in the estuary. Large volumes of sediment have been eroded from the entrance region and deposited on the continental shelf and in the balance of the estuary, contributing to formation of new land. The bathymetric data indicate that, ignoring erosion at the entrance, 370 to 485 × 10 6m 3 of sediment has been deposited in the estuary since 1868 at an average rate of about 0.5 cm y -1, roughly 5 times the rate at which sea level has fallen locally since the turn of the century. Riverflow data indicate that the seasonal flow cycle of the Columbia River has been significantly altered by regulation and diversion of water for irrigation. The greatest changes have occurred in the last thirty years. Flow variability over periods greater than a month has been significantly damped and the net discharge has been slightly reduced. These changes in riverflow are too recent to be reflected in the available in the available bathymetric data. Results from a laterally averaged, multiple-channel, two-dimensional numerical flow model (described in HAMILTON, 1990) suggest that the changes in morphology and riverflow have reduced mixing, increased stratification, altered the response to fortnightly (neap-spring) changes in tidal forcing, and decreased the

Pollution in the estuary of the Baracoa river, La Habana, Cuba

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Regla Duthit Somoza

2011-04-01

Full Text Available The environmental quality of the Baracoa river estuary was studied from the physic (temperature and salinity, chemic variables (dissolved oxygen, oxygen biochemical demand (DBO, oxygen chemical demand (DQO, nitrogen cycle, inorganic phosphorus and total phosphorus and the microbiological variables (total and thermotolerant coliforms and faecal streptococci. The samplings were made on February 2006, May and October 2007. Spatial distribution of the physical and chemical parameters measured suggests that the estuary is dominated by the marine conditions. The salinity and temperature analyses show that in general the characteristics of the estuary could be influenced by the contribution of the river basin drainage. In general, the concentrations of the measured parameters in the Baracoa river estuary, strongly suggest that this area is under influence of human activities on the river basin, due to the low levels of dissolved oxygen and an oxygen average deficit of -1.6 mg/L. nthropogenic actions in this estuary are mainly related to the emission of domestic and farming rejects without suitable treatment. This is visibly associated with the observed values of the total coliforms concentrations as well as the concentration of faecal streptococci, that surpassed reference values from the Cuban norm for water quality, following on bad or doubtful quality levels pointing out negatively measurements made next to the communication channel the estuary and the El Doctor lagoon.

Estimativa da prevalência de infeccções micobacterianas em escolares na Guanabara, através de testes intradérmicos com PPD-Rt 23 E PPD-B

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Eliana Dessaune Madeira Christovão

1975-06-01

Full Text Available Foram testados 543 escolares do Estado da Guanabara, Brasil, na faixa etária de 12 a 14 anos, quanto à hipersensibilidade tuberculínica ao PPD-Rt 23 e ao PPD-B. Confirmou-se a alta prevalência de sensibilidade às tuberculoproteínas em crianças, obtendo-se 33,65% de reatores fortes ao PPD-Rt 23. Da população estudada 85,63% reagiu ao PPD-B, sendo que 6,26% apresentou reação maior a esta tuberculina que ao PPD-Rt 23, sugerindo uma hipersensibilização pelo bacilo Battey, ou outra microbactéria mais relacionada antigenicamente a esse microrganismo que ao Mycobacterium tuberculosis.

Cladocerans (Branchiopoda) of a tropical estuary in Brazil

OpenAIRE

Paranaguá, M. N; Neumann-Leitão, S; Nogueira-Paranhos, J. D; Silva, T. A.; Matsumura-Tundisi, T.

2005-01-01

The study was conducted in the Capibaribe river estuary in Recife (Brazil) to assess the role played by cladocerans in a eutrophic environment. Samplings were carried out monthly at 4 fixed stations along the estuary from July 1987 to June 1988. Collections were made with a plankton net of 65 micrometers mesh size. Six cladocerans species were registered: Penilia avirostris, Diaphanosoma spinulosum, Chydorus barroisi, Ceriodaphnia rigaudi, Ilyocryptus spinifer, and Moina micrura. The most fre...

Dynamics of circulation and salt balance in the upper reaches of Periyar river estuary

Digital Repository Service at National Institute of Oceanography (India)

Varma, P.U.; Pylee, A.; Sankaranarayanan, V.N.

The Eulerian residual currents of the upper reaches of Periyar estuary (Kerala, India) were directed down the estuary throughout the water column during the monsoon season. During the summer months the residual flow was directed up the estuary...

Understanding the fate of iron in a modern temperate estuary: Leirarvogur, Iceland

International Nuclear Information System (INIS)

Byrne, Gemma M.; Worden, Richard H.; Hodgson, David M.; Polya, David A.; Lythgoe, Paul R.; Barrie, Craig D.; Boyce, Adrian J.

2011-01-01

Highlights: → Fluvial Fe (aq) and Fe (total) concentrations drop upon mixing with seawater in estuaries. → The majority of Fe in estuaries is lost in the bay-head delta. → Our results suggest that the bay-head delta is a key location in Fe-mineral formation. → Isotopic variation in estuarine waters may play a role in the formation of Fe-minerals. - Abstract: Fluvial dissolved Fe concentrations decrease upon mixing with seawater, resulting in the formation of Fe-floccules. However, a clear understanding of the fate of these floccules has yet to be established. Assessing how tidal processes affect the formation of Fe-colloids in the Leirarvogur estuary, SW Iceland, is an important step in understanding the formation and potential deposition of estuarine Fe-rich minerals within this estuarine system. The Leirarvogur estuary drains predominately Fe-rich basalt, increasing the likelihood of detecting changes in Fe-phases. Fluvial waters and local lake waters that drain into the estuary were compared and the effects of seasonal changes were considered, in an attempt to understand how varying end-members and external factors play a role in Fe-rich mineral formation. Aqueous and colloidal Fe concentrations were found to be greater towards the head of the Leirarvogur estuary, suggesting that potential Fe-rich minerals and complexes are forming at sites of fluvial input. Increasing suspended colloidal Fe towards the estuary mouth suggests that Fe-colloids are readily transported seaward.

78 FR 68995 - Safety Zone: Vessel Removal From the Oakland Estuary, Alameda, CA

Science.gov (United States)

2013-11-18

...-AA00 Safety Zone: Vessel Removal From the Oakland Estuary, Alameda, CA AGENCY: Coast Guard, DHS. ACTION... waters of the Oakland Estuary just north of the Park Street Bridge in Alameda, CA in support of the Oakland Estuary Closure for the Vessel Removal Project on November 4, 2013 through November 22, 2013. This...

Vitamin B@d12@@ concentrations in Mandovi and Zuari estuaries

Digital Repository Service at National Institute of Oceanography (India)

De; Rajendran, A.

Bioassay method using @iCyclotella nana@@ (clone 13) was employed for the estimation of Vitamin B@d12@@ in Mandovi and Zuari estuaries. At the mouth of the Mandovi estuary, B@d12@@ concentration varied between 0.38 and 7.0 ng/l in surface water...

Plutonium in Atlantic coastal estuaries in the southeastern United States

International Nuclear Information System (INIS)

Hayes, D.W.; LeRoy, J.H.; Cross, F.A.

1975-01-01

A survey was made to begin to provide baseline information on the Pu distribution of representative estuarine and coastal areas of the southeastern United States. Sediments and marsh grass (Spartina) were collected and analyzed from three locations within a tidal marsh. In three estuaries (Savannah, Neuse, and Newport), the suspended particulate matter (1 μm and greater) was filtered from waters with different salinities, and the plutonium content of the particulates determined. The Savannah River estuary, in addition to fallout Pu, has received up to 0.3 Ci of Pu from the Savannah River Plant (SRP) of the U. S. Energy Research and Development Administration. The SRP plutonium has a variable isotopic composition that can influence Pu isotopic ratios in the estuarine system. The other estuaries do not have nuclear installations upstream. Data are included on the content of 238 Pu, 239 Pu, and 240 Pu in sediments and marsh grass of the Savannah River estuary

Habitat Scale Mapping of Fisheries Ecosystem Service Values in Estuaries

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Timothy G. O'Higgins

2010-12-01

Full Text Available Little is known about the variability of ecosystem service values at spatial scales most relevant to local decision makers. Competing definitions of ecosystem services, the paucity of ecological and economic information, and the lack of standardization in methodology are major obstacles to applying the ecosystem-services approach at the estuary scale. We present a standardized method that combines habitat maps and habitat-faunal associations to estimate ecosystem service values for recreational and commercial fisheries in estuaries. Three case studies in estuaries on the U.S. west coast (Yaquina Bay, Oregon, east coast (Lagoon Pond, Massachusetts, and the Gulf of Mexico (Weeks Bay, Alabama are presented to illustrate our method's rigor and limitations using available data. The resulting spatially explicit maps of fisheries ecosystem service values show within and between estuary variations in the value of estuarine habitat types that can be used to make better informed resource-management decisions.

Suspended sediment fluxes in a tropical estuary, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

AnilKumar, N.; DineshKumar, P.K.; Srinivas, K.

Annual transport processes of suspended sediments in Beypore estuary - a tropical estuary along the south west coast of India - were investigated based on time series measurements within the system. It's observed that the sediment transport...

Geographic specificity of Aroclor 1268 in bottlenose dolphins (Tursiops truncatus) frequenting the Turtle/Brunswick River Estuary, Georgia (USA)

Energy Technology Data Exchange (ETDEWEB)

Pulster, Erin L. [Marine Sciences Department, Savannah State University, Savannah, Georgia, 31404 (United States); Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, Georgia, 31411 (United States)], E-mail: epulster@mote.org; Maruya, Keith A. [Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, Georgia, 31411 (United States)

2008-04-15

Coastal marine resources are at risk from anthropogenic contaminants, including legacy persistent organic pollutants (POPs) with half-lives of decades or more. To determine if polychlorinated biphenyl (PCB) signatures can be used to distinguish among local populations of inshore bottlenose dolphins (Tursiops truncatus) along the southeastern U.S. coast, blubber from free-ranging and stranded animals were collected along the Georgia coast in 2004 and analyzed for PCB congeners using gas chromatography with electron capture and negative chemical ionization mass spectrometric detection (GC-ECD and GC-NCI-MS). Mean total PCB concentrations (77 {+-} 34 {mu}g/g lipid) were more than 10 fold higher and congener distributions were highly enriched in Cl{sub 7}-Cl{sub 10} homologs in free-ranging animals from the Turtle/Brunswick River estuary (TBRE) compared with strandings samples from Savannah area estuaries 90 km to the north. Using principal components analysis (PCA), the Aroclor 1268 signature associated with TBRE animals was distinct from that observed in Savannah area animals, and also from those in animals biopsied in other southeastern U.S estuaries. Moreover, PCB signatures in dolphin blubber closely resembled those in local preferred prey fish species, strengthening the hypothesis that inshore T. truncatus populations exhibit long-term fidelity to specific estuaries and making them excellent sentinels for assessing the impact of stressors on coastal ecosystem health.

Geographic specificity of Aroclor 1268 in bottlenose dolphins (Tursiops truncatus) frequenting the Turtle/Brunswick River Estuary, Georgia (USA)

International Nuclear Information System (INIS)

Pulster, Erin L.; Maruya, Keith A.

2008-01-01

Coastal marine resources are at risk from anthropogenic contaminants, including legacy persistent organic pollutants (POPs) with half-lives of decades or more. To determine if polychlorinated biphenyl (PCB) signatures can be used to distinguish among local populations of inshore bottlenose dolphins (Tursiops truncatus) along the southeastern U.S. coast, blubber from free-ranging and stranded animals were collected along the Georgia coast in 2004 and analyzed for PCB congeners using gas chromatography with electron capture and negative chemical ionization mass spectrometric detection (GC-ECD and GC-NCI-MS). Mean total PCB concentrations (77 ± 34 μg/g lipid) were more than 10 fold higher and congener distributions were highly enriched in Cl 7 -Cl 10 homologs in free-ranging animals from the Turtle/Brunswick River estuary (TBRE) compared with strandings samples from Savannah area estuaries 90 km to the north. Using principal components analysis (PCA), the Aroclor 1268 signature associated with TBRE animals was distinct from that observed in Savannah area animals, and also from those in animals biopsied in other southeastern U.S estuaries. Moreover, PCB signatures in dolphin blubber closely resembled those in local preferred prey fish species, strengthening the hypothesis that inshore T. truncatus populations exhibit long-term fidelity to specific estuaries and making them excellent sentinels for assessing the impact of stressors on coastal ecosystem health

The impact of dredging on residence time in the Amba estuary, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Velamala, S.N.; Thomas, J.; Bari, S.; Kachave, S.

for the Musa estuary (Persian Gulf), Payandeh, Zaker and Niksokhan (2014) showed that the persistency of currents was a useful indicator for identifying areas of pollutant load accumulation. The RTs have also been studied by several authors (e.g. Luff....W.A Naqvi, Director, National Institute of Oceanography, India, for their constant encouragement and support during the work. Authors would also like to express their gratitude to Lisa V. Lucas, Geological Survey, US for her comments on this manuscript...

76 FR 9709 - Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary

Science.gov (United States)

2011-02-22

... Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary AGENCY... the San Francisco Bay/ Sacramento-San Joaquin Delta Estuary (Bay Delta Estuary) in California. EPA is... programs to address recent significant declines in multiple aquatic species in the Bay Delta Estuary. EPA...

A note on the comparative turbidity of some estuaries of the Americas

Science.gov (United States)

Uncles, R.J.; Smith, R.E.

2005-01-01

Field data from 27 estuaries of the Americas are used to show that, in broad terms, there is a large difference in turbidity between the analyzed east and west-coast estuaries and that tidal range and tidal length have an important influence on that turbidity. Generic, numerical sediment-transport modeling is used to illustrate this influence, which exists over a range of space scales from, e.g., the Rogue River Estuary (few km, few mg l-1) to the Bay of Fundy (hundreds of km, few g l-1). The difference in Pacific and Atlantic seaboard estuarine turbidity for the analyzed estuaries is ultimately related to the broad-scale geomorphology of the two continents.

Aplicações de Técnicas Geofísicas na Parte Emersa da Baía de Guanabara

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Paula Lúcia Ferrucio da Rocha

2003-01-01

Full Text Available This paper presents the application of the geophysical techniques on twoinvestigations around of Baía de Guanabara, Rio de Janeiro. The first one was carriedout in the area of the Petroflex, a petrochemical industry, located at Campos Elíseosarea in the bank of the bay and the second one at Ilha do Fundão, one of the islandslocated in Guanabara bay. According to Anjos et al.. (2001 the research at Petroflex area was part of thecompany Social Project: “Conheça seu Manguezal” (Knowing your mangrove. For thisresearch the geophysical survey was applied within the industrial park in order to identifysolid waste contamination (rubber, plastic and metal barrels. The Ground PenetratingRadar (GPR technique was used with the RAMAC/MALA equipment. The study areaconsists of clay and sands deposited in marine conditions, which are frequently contami-nated by salt water. In general, the GPR results obtained in both media, clay material andsediments saturated with salt water are not satisfactory. However the results obtained in thePetroflex area were good. The stratigraphic sequence in the area is the following, from topto bottom: The first bed is a clay landfill, the second bed is formed by dark marine clay, andthe third bed is composed of fine-grained sand with marine shells. The surveys originatedsections with average depths of 14 m and average velocity of 70 m/µs. The results showedtwo physical discontinuities within the second bed (marine clay, which possibly representa Pleistocene platform exposition, described in the literature as Guanabariana Regression.It was also possible to identify anomalies within the first bed (clay landfill represented bysignal attenuation, and the others identify waste deposits, where the presence of burieddrums was verified. Such work has demonstrated the success of GPR applicability even toclay soil contaminated by salt water. The Ilha do Fundão where the second investigation took place, according toRocha et al

[Vulnerability assessment on the coastal wetlands in the Yangtze Estuary under sea-level rise].

Science.gov (United States)

Cui, Li-Fang; Wang, Ning; Ge, Zhen-Ming; Zhang, Li-Quan

2014-02-01

To study the response of coastal wetlands to climate change, assess the impacts of climate change on the coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisite for securing coastal ecosystems. In this paper, the possible impacts of sea level rise caused by climate change on the coastal wetlands in the Yangtze Estuary were analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model and IPCC definition on the vulnerability. An indicator system for vulnerability assessment was established, in which sea-level rise rate, subsidence rate, habitat elevation, inundation threshold of habitat and sedimentation rate were selected as the key indicators. A quantitatively spatial assessment method based on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability index for the assessment of coastal wetlands in the Yangtze Estuary under the scenarios of sea-level rise. The vulnerability assessments on the coastal wetlands in the Yangtze Estuary in 2030 and 2050 were performed under two sea-level rise scenarios (the present sea-level rise trend over recent 30 years and IPCC A1F1 scenario). The results showed that with the projection in 2030 under the present trend of sea-level rise (0.26 cm x a(-1)), 6.6% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.8% and 0.2% of the coastal wetlands were in low and moderate vulnerabilities, respectively. With the projection in 2030 under the A1F1 scenario (0.59 cm x a(-1)), 9.0% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.5%, 1.0% and 0.3% of the coastal wetlands were in the low, moderate and high vulnerabilities, respectively.

Late Holocene evolution and increasing pollution in Guanabara Bay, Rio de Janeiro, SE Brazil

International Nuclear Information System (INIS)

Vilela, Claudia Gutterres; Figueira, Brígida Orioli; Macedo, Mariana Cardoso; Baptista Neto, José Antonio

2014-01-01

Highlights: • Foraminifera along the cores confirmed increasing of pollution toward the present. • Foraminifera correlated studies inferred loss of old mangrove systems. • Radiocarbon dates integrated to sediment rates marked the European settlement. • Ammonia tepida is dominant at upper intervals, as a human pollution bioindicator. • Buliminella elegantissima was dominant at core deeper samples before the discovery by Europeans. - Abstract: To detect changes during the Late Holocene and historical periods in Guanabara Bay, the paleoecological and ecological parameters from nine cores were analysed using foraminiferal assemblages and bioindicators. Using radiocarbon dates and sedimentation rates in the cores, it was possible to detect the first Europeans’ arrival in the 16th century. Foraminiferal bioindicators of organic matter and human pollution were correlated with radiocarbon dates from the bottom and middle of the cores in each region and revealed an increase in pollution along the cores. The foraminiferal results were compared with total organic carbon (TOC) values before, during and after European settlement and showed a historical increase in organic matter. Pristine mangrove ecosystems are characterised by agglutinated species such as Ammotium salsum, and the presence of this organism also confirmed the extent of historical mangrove forests. Ammonia tepida, Buliminella elegantissima and Elphidium excavatum were the dominant species, but they presented distinct patterns over time. B. elegantissima was dominant before the European influence in older sediments with high organic matter content that were found at deeper intervals. A. tepida is dominant in younger sediments at upper intervals, as a bioindicator of human pollution

Effect of water flux and sediment discharge of the Yangtze River on PAHs sedimentation in the estuary.

Science.gov (United States)

Li, Rufeng; Feng, Chenghong; Wang, Dongxin; He, Maozhi; Hu, Lijuan; Shen, Zhenyao

2016-12-01

Historical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and their carriers (i.e., organic matter and mineral particles) in the sediment cores of the Yangtze Estuary were investigated, with emphasis laid on the role of the Yangtze River. Grain size component of sediments (clay, silt, and sand) and organic carbon (black carbon and total organic carbon) in the sediment cores were markedly affected by water flux and sediment discharge of the Yangtze River. Qualitative and quantitative analysis results showed that sands and black carbon acted as the main carriers of PAHs. The sedimentation of two-ring to three-ring PAHs in the estuary had significant correlations with water flux and sediment discharge of the Yangtze River. The relative lower level of the four-ring and five-ring to six-ring PAHs concentrations appeared around the year 2003 and remained for the following several years. This time period accorded well with the water impoundment time of the Three Gorges Reservoir. The decreased level of two-ring to three-ring PAHs occurred in the year 1994, and the peak points around the year 2009 indicated that PAHs sedimentation in the estuary also had close relationship to severe drought and flood in the catchments. The findings presented in this paper could provide references for assessing the impacts of water flux and sediment discharge on the historical deposition of PAHs and their carriers in the Yangtze Estuary.

Carbonate system and nutrients in the Pearl River estuary, China: Seasonal and inter-annual variations

Science.gov (United States)

Guo, X.

2017-12-01

Located in southern China and surrounded by several metropolis, the Pearl River estuary is a large subtropical estuary under significant human perturbation. We examined the impact of sewage treatment rate on the water environmental factors. Carbonate system parameters (Dissolved inorganic carbon or DIC, Total alkalinity or TA, and pH), and nutrients were surveyed in the Pearl River estuary from 2000 to 2015. Spatially, concentrations of nutrients were high at low salinity and decreased with salinity in both wet and dry seasons although seasonal variation occurred. However, distribution patterns of DIC and TA differed in wet and dry seasons. In wet season, both DIC and TA were low at low salinity (600-1500 umol kg-1) and increased with salinity, but in dry season they were high at low salinity (3000-3500 umol kg-1) and decreased with salinity. Compared with the years before 2010, both values and distribution patterns of DIC, TA and pH were similar among the years in wet season, but they were conspicuously different in the upper estuary in dry season. Both DIC and TA were more than 1000 umol kg-1 lower than those in the years before 2010. For nutrients at low salinity, the ammonia concentration was much lower in the years after 2010 (200 vs. 400 umol kg-1 in wet season and 400 vs. 800 umol kg-1 in dry season), but nitrate concentration was slightly higher (180 vs 120 mmol kg-1 in wet season and 200 vs 180 mmol kg-1 in dry season). As a reference, carbonate system parameters and nutrients were stable among the 16 years in the adjacent northern South China Sea. The variations in biogeochemical processes induced by nutrients concentration and structure as a result of sewage discharge will be discussed in detail. The decrease in DIC, TA and nutrients in the upper Pearl River estuary after 2010 was due mainly to the improvement of sewage treatment rate and capacity.

Waterfowl migration and distribution in North West estuaries. V. 1

International Nuclear Information System (INIS)

Clark, N.A.; Kirby, J.S.; Langston, R.H.W.; Donald, P.; Mawdesley, T.; Evans, J.

1990-12-01

Waterfowl populations may be affected by proposed tidal barrage across the Mersey. This study had three objectives:-(1) to evaluate the patterns of usage of the intertidal flats of the Mersey estuary by waders and wildfowl and to establish which are the preferred areas; (2) to identify the places of origin and movement patterns of the populations of waders and wildfowl that visit the Mersey Estuary; and (3) to evaluate evidence regarding the capacity of British estuaries to absorb waders and wildfowl populations which might be displaced by a Mersey Barrage. The text and tables and results only are presented in Volume 1. (author)

Picophytoplankton community in a tropical estuary: Detection of Prochlorococcus-like populations

Digital Repository Service at National Institute of Oceanography (India)

Mitbavkar, S.; Rajaneesh, K.M.; Anil, A.C.; Sundar, D.

The influence of hydrography on the picophytoplankton (PP) abundance in estuaries was studied by sampling along a salinity gradient in an Indian estuary. Prochlorococcus-like cells were detected at salinities ranging from 0.06 to 35, which otherwise...

Maturation of the penaeid prawn Metapenaeus moyebi in Mandovi Estuary, Goa

Digital Repository Service at National Institute of Oceanography (India)

Nair, S.R.S.; Achuthankutty, C.T; Parulekar, A

Metapenaeus moyebi contributed a good share of penaeid prawn population in the Mandovi Estuary of Goa, India throughout the year. Both males and females of this species with fully mature gonads were observed in the estuary, suggesting further...

Salt intrusion in multi-channel estuaries: a case study in the Mekong Delta, Vietnam

Directory of Open Access Journals (Sweden)

A. D. Nguyen

2006-01-01

Full Text Available There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictive. The theory uses analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. It applies to single-channel topographies and estuaries that demonstrate moderate tidal damping. The Mekong delta is a multi-channel estuary where the tide is damped due to a relatively strong river discharge (in the order of 2000 m3/s, even during the dry season. As a result the Mekong is a strongly riverine estuary. This paper aims to test if the theory can be applied to such a riverine multi-channel estuary, and to see if possible adjustments or generalisations need to be made. The paper presents salt intrusion measurements that were done by moving boat in 2005, to which the salt intrusion model was calibrated. The theory has been expanded to cater for tidal damping. Subsequently the model has been validated with observations made at fixed locations over the years 1998 and 1999. Finally it has been tested whether the Mekong calibration fits the overall predictive equations derived in other estuaries. The test has been successful and led to a slight adjustment of the predictive equation to cater for estuaries that experience a sloping bottom.

Nutritional condition of fish larvae in South African estuaries: an ...

African Journals Online (AJOL)

Nutritional condition of fish larvae in South African estuaries: an appraisal of three biochemical methods. D Costalago, N Strydom, C Frost. Abstract. Estuaries are exposed to a number of threats and many South African estuarine systems are functionally and structurally altered. The extent to which fish are affected by these ...

Sediment-water distribution of perfluorooctane sulfonate (PFOS) in Yangtze River Estuary

International Nuclear Information System (INIS)

Pan Gang; You Chun

2010-01-01

Analysis of Perfluorooctane sulfonate (PFOS) distribution in water and sediment in Yangtze River Estuary showed that the estuary was a sink for PFOS. Salinity was an important parameter in controlling the sediment-water interactions and the fate or transport of PFOS in the aquatic environment. As the salinity (S per mille ) increased from 0.18 to 3.31, the distribution coefficient (K d ) between sediment and water linearly increased from 0.76 to 4.70 L g -1 . The study suggests that PFOS may be carried with the river water and transported for long distances before it reaches to the sea and largely scavenged to the sediment in the estuaries due to the dramatic change in salinity. - PFOS may be largely scavenged to the sediment in estuaries due to the dramatic change in salinity during its transport from lands to oceans.

Detection of metal induced cytopathological alterations and DNA damage in the gills and hepatopancreas of green mussel Perna viridis from Ennore Estuary, Chennai, India

International Nuclear Information System (INIS)

Vasanthi, Lourduraj A.; Revathi, Peranandam; Babu Rajendran, Ramaswamy; Munuswamy, Natesan

2017-01-01

This study report the impact of heavy metals on cytopathology and DNA damage in the gills and hepatopancreas of Perna viridis collected from Ennore estuary and the Kovalam coastal waters. Principal Component Analysis (PCA) showed significant differences among all variables at the scale of plots. The ultrastructural alterations such as lack of microvilli, distorted mitochondria, electron dense particles and the presence of large mucous droplets were common in the gill and hepatopancreatic cells of mussels from Ennore estuary. However, the gill and hepatopancreatic cells of P. viridis from Kovalam revealed normal compartmentalization of cells. The percentage of tail DNA in the mussels from Ennore estuary was recorded as 12.44 and 10.14% in the gills and hepatopancreas respectively. Overall, it has been demonstrated that the Comet and cytopathological assays are useful biomarkers to assess the level of pollution and it provide reliable information on ecotoxicology and genotoxicology of coastal waters. - Highlights: • Bioaccumulation of heavy metals was studied in P. viridis from Ennore estuary. • Heavy metal accumulation leads to severe cellular and DNA damage. • Comet assay and cytopathology proved to be a biomarker in ecotoxicology. • The data justifies the need of remedial measures along Ennore Estuary.

Modeling In-stream Tidal Energy Extraction and Its Potential Environmental Impacts

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhaoqing; Wang, Taiping; Copping, Andrea; Geerlofs, Simon H.

2014-09-30

In recent years, there has been growing interest in harnessing in-stream tidal energy in response to concerns of increasing energy demand and to mitigate climate change impacts. While many studies have been conducted to assess and map tidal energy resources, efforts for quantifying the associated potential environmental impacts have been limited. This paper presents the development of a tidal turbine module within a three-dimensional unstructured-grid coastal ocean model and its application for assessing the potential environmental impacts associated with tidal energy extraction. The model is used to investigate in-stream tidal energy extraction and associated impacts on estuarine hydrodynamic and biological processes in a tidally dominant estuary. A series of numerical experiments with varying numbers and configurations of turbines installed in an idealized estuary were carried out to assess the changes in the hydrodynamics and biological processes due to tidal energy extraction. Model results indicated that a large number of turbines are required to extract the maximum tidal energy and cause significant reduction of the volume flux. Preliminary model results also indicate that extraction of tidal energy increases vertical mixing and decreases flushing rate in a stratified estuary. The tidal turbine model was applied to simulate tidal energy extraction in Puget Sound, a large fjord-like estuary in the Pacific Northwest coast.

The effects of hydrological dynamics on benthic diatom community structure in a highly stratified estuary: The case of the Ebro Estuary (Catalonia, Spain)

Science.gov (United States)

Rovira, L.; Trobajo, R.; Leira, M.; Ibáñez, C.

2012-04-01

This study of the distribution of benthic diatom assemblages and their relationship with environmental factors in a highly stratified Mediterranean estuary, i.e. the Ebro Estuary, shows the importance of hydrological dynamics to explain the features of the diatom community in such an estuary, where river flow magnitude and fluctuations imply strong physicochemical variability especially in sites close to the sea. Eight sites along the estuary were sampled during 2007-2008 both at superficial and deep water layers, in order to gather both horizontal and vertical estuarine physicochemical and hydrological gradients. Canonical Variates Analysis and Hierarchical Cluster Analysis segregated diatom community in two assemblages depending on the dynamics of the salt-wedge. The diatom assemblages of riverine conditions (i.e. without salt-wedge influence) where characterised by high abundances of Cocconeis placentula var. euglypta and Amphora pediculus, meanwhile high abundances of Nizschia frustulum and Nitzschia inconspicua were characteristic of estuarine conditions (i.e. under salt-wedge influence). Redundancy Analysis showed that both diatom assemblages responded seasonally to Ebro River flows, especially in estuarine conditions, where fluctuating conditions affected diatom assemblages both at spatial and temporal scale.

Natural 222Rn and 220Rn indicate the impact of the Water–Sediment Regulation Scheme (WSRS) on submarine groundwater discharge in the Yellow River estuary, China

International Nuclear Information System (INIS)

Xu, Bochao; Xia, Dong; Burnett, William C.; Dimova, Natasha T.; Wang, Houjie; Zhang, Longjun; Gao, Maosheng; Jiang, Xueyan; Yu, Zhigang

2014-01-01

Highlights: • 220 Rn and 222 Rn were combined to locate intensive SGD sites. • Influence of WSRS to SGD was found for the first time. • SGD was a dominant nutrient pathway in the Yellow River estuary. - Abstract: Submarine groundwater discharge (SGD) in estuaries brings important influences to coastal ecosystems. In this study, we observed significant SGD in the Yellow River estuary, including a fresh component, during the Water–Sediment Regulation Scheme (WSRS) period. We used the 222 Rn and 220 Rn isotope pair to locate sites of significant SGD within the study area. Three apparent SGD locations were found during a non-WSRS period, one of which became much more pronounced, according to the remarkably elevated radon levels, during the WSRS. Increased river discharge (from 245 m 3 s −1 to 3560 m 3 s −1 ) and the elevated river water level (from 11 m to 13 m) during the WSRS led to a higher hydraulic head, enhancing groundwater discharge in the estuary. Our results suggest that high river discharge (>3000 m 3 s −1 ) might be necessary for elevated fresh submarine groundwater discharging (FSGD). Vertical profiles of salinity, DO and turbidity anomalies along the benthic boundary layer also indicated significant FSGD in the estuary during the WSRS. Nutrient concentrations had positive correlations with 222 Rn during a 24-h observation, which indicates that SGD is a dominant nutrient pathway in this area

Spatio-temporal variation in δ13CDIC of a tropical eutrophic estuary (Cochin estuary, India) and adjacent Arabian Sea

Science.gov (United States)

Bhavya, P. S.; Kumar, Sanjeev; Gupta, G. V. M.; Sudharma, K. V.; Sudheesh, V.

2018-02-01

Carbon isotopic composition of dissolved inorganic carbon (δ13CDIC) in the Cochin estuary, a tropical eutrophic estuary along the southwest coast of India, and the adjacent coastal Arabian Sea was measured to understand spatio-temporal variability in sources and processes controlling inorganic carbon (C) dynamics in this estuarine-coastal system. δ13CDIC in the Cochin estuary showed wide variation during three different seasons (premonsoon: - 12.2 to - 3.26‰; monsoon: - 13.6 to - 5.69‰; and postmonsoon: - 6.34 to + 0.79‰). Detailed mixing curve approximation modeling along with relationships of δ13CDIC with dissolved oxygen and nutrients suggest dominant role of freshwater mixing and degassing of CO2 on DIC dynamics during wet seasons (premonsoon and monsoon). Excess CO2 brought in by rivers and in situ production due to respiration in the Cochin estuary result into one of the highest pCO2 observed in estuarine systems, leading to its degassing. During postmonsoon, a relatively dry period with high salinity, calcite precipitation was a major process with calcite saturation index > 1 at few locations. Relatively lower average surface values of δ13CDIC in the coastal Arabian Sea (premonsoon: + 0.95‰; monsoon: + 0.88‰; and postmonsoon: + 0.66‰) compared to the predicted open ocean value along with mixing curve modeling suggest dominance of respiration/organic matter (OM) degradation over primary productivity. Estuarine influence on coastal DIC dynamics was observed in nearshore region ( 10 km), whereas evidence of upwelling was found at farther locations.

A 2D fluid motion model of the estuarine water circulation: Physical analysis of the salinity stratification in the Sebou estuary

Science.gov (United States)

Haddout, Soufiane; Maslouhi, Abdellatif; Magrane, Bouchaib

2018-02-01

Estuaries, which are coastal bodies of water connecting the riverine and marine environment, are among the most important ecosystems in the world. Saltwater intrusion is the movement of coastal saline water into an estuary, which makes up-estuary water, that becomes salty due to the mixing of freshwater with saltwater. It has become a serious environmental problem in the Sebou estuary (Morocco) during wet and dry seasons, which have a considerable impact on residential water supply, agricultural water supply as well as urban industrial production. The variations of salt intrusion, and the vertical stratification under different river flow conditions in the Sebou estuary were investigated in this paper using a two-dimensional numerical model. The model was calibrated and verified against water level variation, and salinity variation during 2016, respectively. Additionally, the model validation process showed that the model results fit the observed data fairly well ( R2 > 0.85, NSC > 0.89 and RMSE = 0.26 m). Model results show that freshwater is a dominant influencing factor to the saltwater intrusion and controlled salinity structure, vertical stratification and length of the saltwater intrusion. Additionally, the extent of salinity intrusion depends on the balance between fresh water discharges and saltwater flow from the sea. This phenomenon can be reasonably predicted recurring to mathematical models supported by monitored data. These tools can be used to quantify how much fresh water is required to counterbalance salinity intrusion at the upstream water intakes.

Radium isotopes in the Orinoco estuary and Eastern Caribbean Sea

International Nuclear Information System (INIS)

Moore, W.S.; Todd, J.F.

1993-01-01

Radium isotopes provide a means of identifying the source of freshened waters in the ocean and determining the time elapsed since these waters were in the estuary. The authors present evidence that during April, waters from the Amazon mixing zone pass within 50 km of the mouth of the Orinoco River. These Amazon waters are characterized by a lower 228 Ra/ 226 Ra activity ratio (AR) than are waters from the Orinoco at similar salinities. During autumn, the increased discharge of the Orinoco displaces the freshened Amazon waters seaward, yet the two can be distinguished clearly. Within the Caribbean Sea, waters of Orinoco origin carry a characteristic radium signature including excess activities of 224 Ra. This isotope may be used to estimate the time elapsed since the waters were removed from contact with sediments. Current speeds based on 224 Ra dating ranged from 15 to 33 cm/s during April. The radium isotopes also provide an assessment of sediment mixing in the estuary. During low discharge (April), considerable mixing of older sediment by physical or biological processes or dredging maintained high activities of 228 Ra in the estuary and produced the highest 228 Ra/ 226 Ra AR's yet measured in any estuary. During high discharge (September), a large fraction of the 228 Ra was derived from desorption from fresh sediment rather than mixing of older sediments. Activities of 224 Ra were high in the estuary during both high and low discharge, indicating that considerable mixing of recently introduced sediment must occur during each period. During April, 224 Ra and 228 Ra activities in the water were about equal, indicating that most of the sediment being resuspended had been stored in the estuary long enough to reestablish radioactive equilibrium in the 232 Th decay series (i.e., 20 years). 19 refs., 11 figs., 3 tabs

Effects of mud supply on large-scale estuary morphology and development over centuries to millennia

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L. Braat

2017-10-01

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

Estuaries as filters: the role of tidal marshes in trace metal removal.

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Johannes Teuchies

Full Text Available Flux calculations demonstrate that many estuaries are natural filters for trace metals. Yet, the underlying processes are poorly investigated. In the present study, it was hypothesized that intertidal marshes contribute significantly to the contaminant filter function of estuaries. Trace metal concentrations and sediment characteristics were measured along a transect from the subtidal, over an intertidal flat and marsh to a restored marsh with controlled reduced tide. Metal concentrations in the intertidal and restored marsh were found to be a factor two to five higher than values in the subtidal and intertidal flat sediments. High metal concentrations and high accretion rates indicate a high metal accumulation capacity of the intertidal marshes. Overbank sedimentation in the tidal marshes of the entire estuary was calculated to remove 25% to 50% of the riverine metal influx, even though marshes comprise less than 8% of the total surface of the estuary. In addition, the large-scale implementation of planned tidal marsh restoration projects was estimated to almost double the trace metal storage capacity of the present natural tidal marshes in the estuary.

Estuaries as Filters: The Role of Tidal Marshes in Trace Metal Removal

Science.gov (United States)

Teuchies, Johannes; Vandenbruwaene, Wouter; Carpentier, Roos; Bervoets, Lieven; Temmerman, Stijn; Wang, Chen; Maris, Tom; Cox, Tom J. S.; Van Braeckel, Alexander; Meire, Patrick

2013-01-01

Flux calculations demonstrate that many estuaries are natural filters for trace metals. Yet, the underlying processes are poorly investigated. In the present study, it was hypothesized that intertidal marshes contribute significantly to the contaminant filter function of estuaries. Trace metal concentrations and sediment characteristics were measured along a transect from the subtidal, over an intertidal flat and marsh to a restored marsh with controlled reduced tide. Metal concentrations in the intertidal and restored marsh were found to be a factor two to five higher than values in the subtidal and intertidal flat sediments. High metal concentrations and high accretion rates indicate a high metal accumulation capacity of the intertidal marshes. Overbank sedimentation in the tidal marshes of the entire estuary was calculated to remove 25% to 50% of the riverine metal influx, even though marshes comprise less than 8% of the total surface of the estuary. In addition, the large-scale implementation of planned tidal marsh restoration projects was estimated to almost double the trace metal storage capacity of the present natural tidal marshes in the estuary. PMID:23950927

Plutonium, radiocesium and radiocobalt in sediments of the Hudson River estuary

International Nuclear Information System (INIS)

Olsen, C.R.; Simpson, H.J.; Trier, R.M.; Columbia Univ., Palisades, NY

1981-01-01

Anthropogenic radionuclides have reached the Hudson estuary as global fallout from nuclear weapons testing and through local releases from commercial nuclear reactors. Significant activities of 238 Pu and 239 , 240 Pu (fallout-derived), 134 Cs and 60 Co (reactor-released), and 137 Cs (derived from both sources), have accumulated in the sediments throughout the estuary, with the primary zone of accumulation near the downstream end of the system in New York harbor. The estuary appears to have trapped nearly all of the 239 , 240 Pu delivered as fallout, and consequently, ocean dumping of dredged harbor sediment is currently the primary means for the net transport of these nuclides to coastal waters. In contrast, only 10-30% of the 137 Cs, 134 Cs and 60 Co delivered to the estuary have been retained on the fine particles which accumulate at a rapid rate in the harbor. (orig./HAE)

Factors governing the pH in a heterotrophic, turbid, tidal estuary

Science.gov (United States)

Hofmann, A. F.; Meysman, F. J. R.; Soetaert, K.; Middelburg, J. J.

2009-01-01

A method to quantify the influence of kinetically modelled biogeochemical processes on the pH of an ecosystem with time variable acid-base dissociation constants is presented and applied to the heterotrophic, turbid Scheldt estuary (SW Netherlands, N Belgium). Nitrification is identified as the main process governing the pH profile of this estuary, while CO2 degassing and advective-dispersive transport "buffer" the effect of nitrification. CO2 degassing accounts for the largest proton turnover per year in the whole estuary. There is a clear inverse correlation between oxygen turnover and proton turnover. The main driver of long-term changes in the mean estuarine pH from 2001 to 2004 is a changing freshwater flow which influences the pH "directly" via [∑CO2] and [TA] and to a significant amount also "indirectly" via [∑NH4+] and the nitrification rates in the estuary.

Effect of Climate Change on Water Temperature and Attainment of Water Temperature Criteria in the Yaquina Estuary, Oregon (USA)

Science.gov (United States)

There is increasing evidence that our planet is warming and this warming is also resulting in rising sea levels. Estuaries which are located at the interface between land and ocean are impacted by these changes. We used CE-QUAL-W2 water quality model to predict changes in water...

Diatomáceas de tanques do cactário do Jardim Botânico, Guanabara, Brasil

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Luis Tavares de Lyra

1974-01-01

Full Text Available O autor analisou a microflora de três tanques situados no Cactário do Jardim Botânico, Rio de Janeiro, Guanabara. Tanque nº 1. Apresentou desenvolvimento muito intenso da microfibra nos mseses mais frios. As diatomáceas foram muito freqüentes. As espécies indicadoras de saprobidade foram as seguintes: Gomphonema gracile Ehr., pinnularia maior. (kutz Cleve, Gomphonema parvulum (kutz Grunow, Navicula mutica Kutz., Pinnularia borealis Ehr., Pinnularia microstauron (Ehr Cleve, Pinnularia acrospheria Breb., Hantzschia amphioxys (Ehr Grunow, Nitzschia palea Kutz., Eutonia pectinalis (Kutz Rabenh. Tanque nº 2. As diatomáceas indicadoras de águas contaminadas, anotamos como segue: Eutonia pectinalis (Kutz Rabenh., Gomphonema parvulum (kutz Grunow, Hanstzschia amphioxys (Ehr Grunow, Navicula mutica Kutz, Pinnularia borealis Ehr., Pinnularia maior (Kutz Cleve, Pinnularia microstauron (Ehr Cleve. Tanque nº 3. Foi bastante reduzida a freqüência da microflora. Comparando-o com os tanques nº 1 e 2, as diatomáceas e clorofícias observadas, mostraram-se diminuídas nos meses mais quentes. Encontramos as seguintes espécies oligosaprobias: Eunotia pectinalis (Kutz Rabenh., Gomphonema gracile ehr., Gomphonema parvulum (Kutz Grunow Hantzschia amphioxys (Ehr Grunow, Pinnularia borealis Ehr., Pinnularia maior (Kutz Cleve. Foram consideradas também as clorofíceas quanto ao regime de saprobidade do material estudado. Eutonia augusta f. crenulata Cleve-Euler e Eutonia veneris var. exsecta Clever-Euler encontradas em nossas amostras, são novas para o Brasil. Um total de 71 espécies foram determinadas de 21 coletas realizadas durante o período de 36 meses.The author analysed the microflorafrom three ponds situated in the Cactarium from the Botanical Garden of Rio de Janeiro, Guanabara. Pond nº 1 - This pond showed a very intensive development of the microflora in the coldermonths. The diatoms were very frequent. Those diatoms that indicate saprobic

Processing watershed-derived nitrogen in a well-flushed New England estuary

Science.gov (United States)

Tobias, C.R.; Cieri, M.; Peterson, B.J.; Deegan, Linda A.; Vallino, J.; Hughes, J.

2003-01-01

Isotopically labeled nitrate (15NO3-) was added continuously to the Rowley estuary, Massachusetts, for 22 d to assess the transport, uptake, and cycling of terrestrially derived nitrogen during a period of high river discharge and low phytoplankton activity. Isotopic enrichment of the 3.5-km tidal prism (150,000 m3) was achieved for the 3 weeks and allowed us to construct a nitrogen mass balance model for the upper estuary. Mean ??15NO3- in the estuary ranged from 300??? to 600???, and approximately 75%-80% of the 15N was exported conservatively as 15NO 3- to the coastal ocean. Essentially all of the 20%-25% of the 15N processed in the estuary occurred in the benthos and was evenly split between direct denitrification and autotrophic assimilation. The lack of water-column 15N uptake was attributed to low phytoplankton stocks and short water residence times (1.2-1.4 d). Uptake of water-column NO3- by benthic autotrophs (enriched in excess of 100???) was a function of NO3- concentration and satisfied up to 15% and 25% of the total nitrogen demand for benthic microalgae and macroalgae, respectively. Approximately 10% of tracer assimilated by benthic autotrophs was mineralized and released back to the water column as 15NH4+. By the end of the study, 15N storage in sediments and marsh macrophytes accounted for 50%-70% of the 15N assimilated in the estuary. These compartments may sequester watershed-derived nitrogen in the estuary for time scales of months to years.

Effects of environmental and water quality parameters on the functioning of copepod assemblages in tropical estuaries

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Araujo, Adriana V.; Dias, Cristina O.; Bonecker, Sérgio L. C.

2017-07-01

We examined changes in the functioning of copepod assemblages with increasing pollution in estuaries, using sampling standardization of the salinity range to enable comparisons. Copepod assemblages were analyzed in four southeast Brazilian estuaries with different water quality levels and hydrodynamic characteristics over two years. We obtained mesozooplankton samples together with environmental and water quality parameters in the estuaries, every two months under predetermined salinities ranging from 15 to 25. The values of parameters, except species size, associated with the functioning of the copepod assemblages (biomass, productivity, and turnover rate) did not differ among estuaries. However, in the more polluted estuaries, the biomass and productivity of copepod assemblages of mesozooplankton were negatively correlated with concentration of pollution indicator parameters. Conversely, in the less polluted estuaries some degree of enrichment still seems to increase the system biomass and productivity, as these parameters were inversely related to indicators of improved water quality. The pollution level of estuaries distorted the relationship between temperature and the efficiency of converting energy to organic matter. In the less polluted estuaries, the relationship between turnover rate and temperature was over 70%, while in the most polluted estuaries, this relationship was only approximately 50%. Our results demonstrated that the functioning of assemblages in the estuaries was affected differently by increasing pollution depending on the water quality level of the system. Thus, investigating the functioning of assemblages can be a useful tool for the analysis of estuarine conditions.

Seasonal distribution and interactions between plankton and microplastics in a tropical estuary

Science.gov (United States)

Lima, A. R. A.; Barletta, M.; Costa, M. F.

2015-11-01

The seasonal migration of a salt wedge and rainfall were the major factors influencing the spatiotemporal distribution of ichthyoplankton and microplastics along the main channel of the Goiana Estuary, NE Brazil. The most abundant taxa were the clupeids Rhinosardinia bahiensis and Harengula clupeola, followed by the achirid Trinectes maculatus (78.7% of the catch). Estuarine and mangrove larvae (e.g. Anchovia clupeoides, Gobionellus oceanicus), as well as microplastics were ubiquitous. During drier months, the salt wedge reaches the upper estuary and marine larvae (e.g. Cynoscion acoupa) migrated upstream until the zones of coastal waters influence. However, the meeting of waterfronts in the middle estuary forms a barrier that retains the microplastics in the upper and lower estuary most part of the year. During the late dry season, a bloom of zooplankton was followed by a bloom of fish larvae (12.74 ind. 100 m-3) and fish eggs (14.65 ind. 100 m-3) at the lower estuary. During the late rainy season, the high freshwater inflow flushed microplastics, together with the biota, seaward. During this season, a microplastic maximum (14 items 100 m-3) was observed, followed by fish larvae maximum (14.23 ind. 100 m-3) in the lower estuary. In contrast to fish larvae, microplastics presented positive correlation with high rainfall rates, being more strictly associated to flushing out/into the estuary than to seasonal variation in environmental variables. Microplastics represented half of fish larvae density. Comparable densities in the water column increase the chances of interaction between microplastics and fish larvae, including the ingestion of smaller fragments, whose shape and colour are similar to zooplankton prey.

76 FR 23306 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

Science.gov (United States)

2011-04-26

... Marine Mammals Incidental to Specified Activities; Russian River Estuary Management Activities AGENCY...) to incidentally harass, by Level B harassment only, three species of marine mammals during estuary... December 31, 2010; and Russian River Estuary Outlet Channel Adaptive Management Plan. NMFS' Environmental...

Mercury and selenium relationship in a tropical estuarine fish

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Ana Carolina Pizzochero

2015-11-01

Full Text Available Aquatic systems have been considered as final sinks for persistent and bioaccumulative toxicants (PBTs, such as metals and organohalogen compounds. Among the trace elements, non-essential metals deserve special attention due to their toxicity. In this context, mercury (Hg should be highlighted due to its toxic effects, which comprise neurotoxicity, nephrotoxicity, hepatotoxicity, genotoxicity, among others. Several studies have highlighted the selenium-mediated methylmercury detoxification process, via mercury selenide formation in tissues of marine vertebrates. Despite being an essential element, selenium may also be toxic in high concentrations. This study focused on Guanabara Bay (GB, a heavily polluted urban estuary in Rio de Janeiro state (Brazil, where the whitemouth croaker (Micropogonias furnieri provides a valuable fishery resource. Therefore, hepatic (Hg and Se and muscular (Hg concentrations of these elements were determined in GB whitemouth croakers. Mercury and selenium measurements were performed by cold vapor atomic absorption spectrometry (CV-AAS and electrothermal AAS (ET-AAS, respectively. Total mercury (THg concentrations in muscle (n=19 ranged from 184.9 to 858.6 (ng/g, while in liver they varied from 11.05 to 1188 (ng/g. Hepatic selenium concentrations ranged from 7820 to 40085 (ng/g. The hepatic Se:THg molar ratio ranged from 40,8 to 3102,5. The results showed a significant correlation between hepatic mercury and selenium levels, but the molar ratio suggests the absence of mercury selenide formation. Some of the Se concentrations found were above the threshold level for freshwater fish (12000 ng/g; however, it is not yet clear if these concentrations are toxic for marine fish as well. More studies are necessary for evaluating the impact of such exposure in fish from Guanabara Bay.

A numerical study of local variations in tidal regime of Tagus estuary, Portugal.

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Dias, João Miguel; Valentim, Juliana Marques; Sousa, Magda Catarina

2013-01-01

Tidal dynamics of shallow estuaries and lagoons is a complex matter that has attracted the attention of a large number of researchers over the last few decades. The main purpose of the present work is to study the intricate tidal dynamics of the Tagus estuary, which states as the largest estuary of the Iberian Peninsula and one of the most important wetlands in Portugal and Europe. Tagus has large areas of low depth and a remarkable geomorphology, both determining the complex propagation of tidal waves along the estuary of unknown manner. A non-linear two-dimensional vertically integrated hydrodynamic model was considered to be adequate to simulate its hydrodynamics and an application developed from the SIMSYS2D model was applied to study the tidal propagation along the estuary. The implementation and calibration of this model revealed its accuracy to predict tidal properties along the entire system. Several model runs enabled the analysis of the local variations in tidal dynamics, through the interpretation of amplitude and phase patterns of the main tidal constituents, tidal asymmetry, tidal ellipses, form factor and tidal dissipation. Results show that Tagus estuary tidal dynamics is extremely dependent on an estuarine resonance mode for the semi-diurnal constituents that induce important tidal characteristics. Besides, the estuarine coastline features and topography determines the changes in tidal propagation along the estuary, which therefore result essentially from a balance between convergence/divergence and friction and advection effects, besides the resonance effects.

Land claim and loss of tidal flats in the Yangtze Estuary.

Science.gov (United States)

Chen, Ying; Dong, Jinwei; Xiao, Xiangming; Zhang, Min; Tian, Bo; Zhou, Yunxuan; Li, Bo; Ma, Zhijun

2016-04-01

Tidal flats play a critical role in supporting biodiversity and in providing ecosystem services but are rapidly disappearing because of human activities. The Yangtze Estuary is one of the world's largest alluvial estuaries and is adjacent to the most developed economic zone in China. Using the Yangtze Estuary as a study region, we developed an automatic algorithm to estimate tidal flat areas based on the Land Surface Water Index and the Normalized Difference Vegetation Index. The total area of tidal flats in the Yangtze Estuary has decreased by 36% over the past three decades, including a 38% reduction in saltmarshes and a 31% reduction in barren mudflats. Meanwhile, land claim has accumulated to 1077 km(2), a value that exceeds the area of the remaining tidal flats. We divided the Yangtze Estuary into Shanghai and Jiangsu areas, which differ in riverine sediment supply and tidal flat management patterns. Although land claim has accelerated in both areas, the decline in tidal flat area has been much greater in Jiangsu than in Shanghai because of abundant supplies of sediment and artificial siltation in the latter area. The results highlight the need for better coastal planning and management based on tidal flat dynamics.

Circulation and mixing process in Vasishta-Godavari estuary, east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Kumar, A.R.S.; Murty, T.V.R.; Rao, M.M.M.; Rao, V.R.; Reddy, B.S.R.

Circulation and Mixing Process in Vasishta-Godavari Estuary, have been studied by using estuarine classification model. Analysis of salinity, salt budget, diffusion coefficients and flushing times based on salinity data of Vasishta-Godavari estuary...

Investigation of the presence of toxic components of petroleum hydrocarbons in Guanabara Bay, Brazil following the 2000 PETROBRAS fuel oil spill

Energy Technology Data Exchange (ETDEWEB)

Romao, Catia Maria [Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renovaveis (IBAMA), Rio de Janeiro, RJ (Brazil). Escritorio de Licenciamento de Petroleo e Nuclear; Vleet, Edward S. Van

2003-07-01

On January 18, 2000, approximately 340,000 gallons of marine fuel 380 oil were released into Guanabara Bay, Rio de Janeiro, Brazil, as a consequence of a pipeline transfer accident at the Duque de Caxias Refinery (PETROBRAS). Two years after the spill, the present investigation (sponsored by Center for Disaster Management and Humanitarian Assistance - College of Public Health - University of South Florida) was conducted to assess the levels of Polycyclic Aromatic Hydrocarbons (PAHs) on samples of water, sediments and edible tissue of the fishes (Mullet - Mugilliza and Croaker - Micropogonias furnieri) collected using two types of device (nets and fish traps) from the spill area in July and August 2002. The fishes samples collected in both months were considered to range from being not contaminated to being moderately contaminated by PAHs. Among all the sediments, only one (Point 10, July 2002) showed a total PAH concentration representing highly contaminated conditions. Except for Point 10, all other sediments could be considered minimally to moderately contaminated. Dissolved PAH concentrations found in the water samples were considered to range from minimally to moderately contaminated. (author)

Water Quality Drivers in 11 Gulf of Mexico Estuaries

Directory of Open Access Journals (Sweden)

Matthew J. McCarthy

2018-02-01

Full Text Available Coastal water-quality is both a primary driver and also a consequence of coastal ecosystem health. Turbidity, a measure of dissolved and particulate water-quality matter, is a proxy for water quality, and varies on daily to interannual periods. Turbidity is influenced by a variety of factors, including algal particles, colored dissolved organic matter, and suspended sediments. Identifying which factors drive trends and extreme events in turbidity in an estuary helps environmental managers and decision makers plan for and mitigate against water-quality issues. Efforts to do so on large spatial scales have been hampered due to limitations of turbidity data, including coarse and irregular temporal resolution and poor spatial coverage. We addressed these issues by deriving a proxy for turbidity using ocean color satellite products for 11 Gulf of Mexico estuaries from 2000 to 2014 on weekly, monthly, seasonal, and annual time-steps. Drivers were identified using Akaike’s Information Criterion and multiple regressions to model turbidity against precipitation, wind speed, U and V wind vectors, river discharge, water level, and El Nino Southern Oscillation and North Atlantic Oscillation climate indices. Turbidity variability was best explained by wind speed across estuaries for both time-series and extreme turbidity events, although more dynamic patterns were found between estuaries over various time steps.

National Estuary Program Study Area Boundaries

Data.gov (United States)

U.S. Environmental Protection Agency — There are 28 National Estuary Programs (NEPs) in the U.S.that implement habitat protection and restoration projects with their partners. This work takes place within...

77 FR 24471 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

Science.gov (United States)

2012-04-24

... Marine Mammals Incidental to Specified Activities; Russian River Estuary Management Activities AGENCY...) to incidentally harass, by Level B harassment only, three species of marine mammals during estuary... Estuary Outlet Channel Adaptive Management Plan; and Feasibility of Alternatives to the Goat Rock State...

Estuary wader capacity following severe weather mortality

International Nuclear Information System (INIS)

Clark, J.A.; Baillie, S.R.; Clark, N.A.; Langston, R.H.W.

1993-01-01

The building of a tidal power barrage across an estuary may lead to substantial changes in its ecology. Many of Britain's estuaries hold internationally important numbers of waders. Careful consideration, therefore, needs to be given to the likely effects of tidal power barrages on wader populations. The opportunity for increased understanding of the mechanisms which govern wader populations was provided by a period of severe winter weather in 1991, which resulted in a substantial mortality of waders in eastern England. Such conditions are known to be stressful to birds and the study objectives were to investigate both the effects of and recovery from severe weather. (author)

How many people use the Three Bays estuary system for recreation?

Science.gov (United States)

Little is known about recreational use on estuaries like Three Bays, MA. We are testing a practical approach to quantify recreational use of the Three Bays estuary system so we can better understand how many people are affected by changes in environmental quality. This involves c...

Heavy metal anomalies in the Tinto and Odiel River and estuary system, Spain

Science.gov (United States)

Nelson, C.H.; Lamothe, P.J.

1993-01-01

The Tinto and Odiel rivers drain 100 km from the Rio Tinto sulphide mining district, and join at a 20-km long estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary by semi-quantitative emission dc-arc spectrographic analysis shows the following upstream to downstream ranges in ppm (??g g-1): As 3,000 to TOC), sandysilty overbank clay has been analyzed to represent suspended load materials. The high content of heavy metals in the overbank clay throughout the river and estuary systems indicates the importance of suspended sediment transport for dispersing heavy metals from natural erosion and anthropogenic mining activities of the sulfide deposit. The organic-poor (0.21-0.37% TOC) river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream but these decrease an order of magnitude in the lower estuary. Although heavy metal contamination of estuary mouth beach sand has been diluted to background levels estuary mud exhibits increased contamination apparently related to finer grain size, higher organic carbon content, precipitation of river-borne dissolved solids, and input of anthropogenic heavy metals from industrial sources. The contaminated estuary mud disperses to the inner shelf mud belt and offshore suspended sediment, which exhibit metal anomalies from natural erosion and mining of upstream Rio Tinto sulphide lode sources (Pb, Cu, Zn) and industrial activities within the estuary (Fe, Cr, Ti). Because heavy metal contamination of Tinto-Odiel river sediment reaches or exceeds the highest levels encountered in other river sediments of Spain and Europe, a detailed analysis of metals in water and suspended sediment throughout the system, and epidemiological analysis of heavy metal effects in humans is appropriate. ?? 1993 Estuarine Research Federation.

The herbicide Glyphosate affects nitrification in the Elbe estuary, Germany

Science.gov (United States)

Sanders, Tina; Lassen, Stephan

2015-04-01

The Elbe River is one of the biggest European rivers discharging into the North Sea. It also transports high amounts of nutrients and pollutants like pesticides. Important source regions of both nutrients and pollutants are located within the river catchment, which is dominated by agricultural land-use. From these agricultural soils, pesticides can be carried via the river and estuary into the North Sea. Glyphosate (N-(phosphonomethyl) glycine) is the most commonly used herbicide worldwide and mainly used to regulate unwanted plant growth and for the expedition of crop ripening. In Germany, ~ 6000 tons of glyphosate are applied yearly in agriculture and private use. Glyphosate is degradable by microorganisms and has a half-life in water of 35 to 60 days. This herbicide specifically inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), an enzyme that catalyzes the biosynthesis of essential aromatic amino acids in plants, fungi, and bacteria. Nitrifying bacteria, which play an important role in the internal nitrogen cycling in the Elbe estuary, also possess this enzyme. The aim of our study was to quantify the concentration of glyphosate in water and sediment samples of the Elbe to get an overview about relevant environmental levels and to assess the impact of glyphosate on inhibition of nitrifying activities. To quantify the effect of glyphosate on nitrification activity, natural samples as well as pure cultures of Nitrosomonas europea (strain Nm50) were incubated with different concentrations of glyphosate over a period of some weeks. The nitrifying activity was determined according to changes of the nitrite and nitrate concentration as well as the cell number. Glyphosate was detectable in water and sediment samples in the Elbe estuary with up to 5 ppb mainly in the Port of Hamburg region. In both incubation experiments an inhibiting effect of glyphosate on nitrification could be shown. The incubated natural water sample was affected by a glyphosate

[Optical characteristics of colored dissolved organic material (CDOM) in Yangtze Estuary].

Science.gov (United States)

Zhu, Wei-Jian; Shen, Fang; Hong, Guan-Lin

2010-10-01

Absorption property of colored dissolved organic material (CDOM) is one of the most important contents to remote sensing of ocean color in estuarine and coastal areas. In this study, the optical properties and mixing behavior of CDOM in surface water of Yangtze Estuary were discussed according to the two surveys in August of 2008 and May of 2009. Based on the research, the absorption coefficient and spectral slope were discussed. It was found that in summer of 2008 CDOM absorption coefficients at 440 nm [a(g) (440)], ranged from 0.20 m(-1) to 0.73 m(-1), while the coefficients in 2009 varied between 0.20 m(-1) and 0.77 m(-1). Statistics showed that the power function model fitted the best in the regression analysis of CDOM absorption spectral. The spectral slopes (S(g2)) of CDOM calculated by the power function model ranged from 5.10 to 7.90 in Summer of 2008 and from 2.95 to 6.11 in Spring of 2009. The highest absorption coefficients of two cruises appeared both in the south passage of the Yangtze Estuary. The absorption coefficient in surfer water was observed varied tremendously in the estuary and the offshore area. And the main reason is affected by the turbidity maximum zone. It is observed that the absorption coefficients of CDOM tended to a homogeneous distribution whilst the layers of water mixed tempestuously, but otherwise it always showed a conservative mixing behavior. Because of the frequent mixture, there is not assured correlativity between S(g2) and a(g) (440). In the offshore area of Yangtze Estuary, the effecting of local production cannot be negligent, which differed from the estuary area. Yet when the hydrological environment was relatively stable, the negative relationship between them was very clear. In conclusion, the optical properties and mixing behavior of CDOM had showed tremendous different characteristics from inside the estuary to outside the estuary because of the influence of complex physical, chemical and hydrology conditions.

Desorption of Ba and 226Ra from river-borne sediments in the Hudson estuary

International Nuclear Information System (INIS)

Li, Y.-H.

1979-01-01

The pronounced desorption of Ba and 226 Ra from river-borne sediments in the Hudson estuary can be explained quantitatively by the drastic decrease in the distribution coefficients of both elements from a fresh to a salty water medium. The desorption in estuaries can augment, at least, the total global river fluxes of dissolved Ba and 226 Ra by one and nine times, respectively. The desorption flux of 226 Ra from estuaries accounts for 17-43% of the total 226 Ra flux from coastal sediments. Two mass balance models depicting mixing and adsorption-desorption processes in estuaries are discussed. (Auth.)

An analytical solution for tidal propagation in the Yangtze Estuary, China

NARCIS (Netherlands)

Zhang, E.F.; Savenije, H.H.G.; Chen, S.L.; Mao, X.H.

2012-01-01

An analytical model for tidal dynamics has been applied to the Yangtze Estuary for the first time, to describe the tidal propagation in this large and typically branched estuary with three-order branches and four outlets to the sea. This study shows that the analytical model developed for a

Biogeochemistry of the MAximum TURbidity Zone of Estuaries (MATURE): some conclusions

NARCIS (Netherlands)

Herman, P.M.J.; Heip, C.H.R.

1999-01-01

In this paper, we give a short overview of the activities and main results of the MAximum TURbidity Zone of Estuaries (MATURE) project. Three estuaries (Elbe, Schelde and Gironde) have been sampled intensively during a joint 1-week campaign in both 1993 and 1994. We introduce the publicly available

Fractionation of rare earth elements in the Mississippi River estuary and river sediments

Science.gov (United States)

Adebayo, S. B.; Johannesson, K. H.

2017-12-01

This study presents the first set of data on the fractionation of rare earth elements (REE) in the mixing zone between the Mississippi River and the Gulf of Mexico, as well as the fractionation of REE in the operationally defined fractions of Mississippi River sediments. This subject is particularly important because the Mississippi river is one of the world's major rivers, and contributes a substantial amount of water and sediment to the ocean. Hence, it is a major source of trace elements to the oceans. The geochemistry of the REE in natural systems is principally important because of their unique chemical properties, which prompt their application as tracers of mass transportation in modern and paleo-ocean environments. Another important consideration is the growth in the demand and utilization of REE in the green energy and technology industries, which has the potential to bring about a change in the background levels of these trace elements in the environment. The results of this study show a heavy REE enrichment of both the Mississippi River water and the more saline waters of the mixing zone. Our data demonstrate that coagulation and removal of REE in the low salinity region of the estuary is more pronounced among the Light REE ( 35% for Nd) compared to the Heavy REE. Remarkably, our data also indicate that REE removal in the Mississippi River estuary is significantly less than that observed in other estuaries, including the Amazon River system. We propose that the high pH/alkalinity of the Mississippi River is responsible for the greater stability of REE in the Mississippi River estuary. The results of sequential extraction of river sediments reveal different Sm/Nd ratios for the various fractions, which we submit implies different 143Nd/144Nd ratios of the labile fractions of the sediments. The possible impact of such hypothesized different Nd isotope signatures of labile fractions of the river sediments on Gulf of Mexico seawater is under investigation.

Waterfowl migration and distribution in North West estuaries. V. 2

International Nuclear Information System (INIS)

Clark, N.A.; Kirby, J.S.; Langston, R.H.W.; Donald, P.; Mawdesley, T.; Evans, J.

1990-12-01

Waterfowl populations may be affected by the proposed tidal barrage across the Mersey. A study was performed with three objectives: (1) to evaluate the patterns of usage of the intertidal flats of the Mersey estuary by waders and wildfowl and to establish which are the preferred areas; (2) to identify the places of origin and movement patterns of the populations of waders and wildfowl that visit the Mersey estuary; and (3) to evaluate evidence regarding the capacity of British estuaries to absorb waders and wildfowl populations which might be displaced by a Mersey Barrage. The text and tables of results of this study have already been presented in Volume 1. Volume 2 contains the figures describing the results (U.K)

Optical Proxies for Dissolved Organic Matter in Estuaries and Coastal Waters

Science.gov (United States)

Osburn, C. L.; Montgomery, M. T.; Boyd, T. J.; Bianchi, T. S.; Coffin, R. B.; Paerl, H. W.

2016-02-01

The flux of terrestrial dissolved organic carbon (DOC) into the coastal ocean from rivers and estuaries is a major part of the ocean's carbon cycle. Absorbing and fluorescing properties of chromophoric dissolved organic matter (CDOM) often are used to fingerprint its sources and to track fluxes of terrestrial DOM into the ocean. They also are used as proxies for organic matter to calibrate remote sensing observations from air and space and from in situ platforms. In general, strong relationships hold for large river dominated estuaries (e.g., the Mississippi River) but little is known about how widely such relationships can be developed in estuaries that have relatively small or multiple riverine inputs. Results are presented from a comparison of six diverse estuarine systems: the Atchafalaya River (ARE), the Mackenzie River (MRE), the Chesapeake Bay (CBE), Charleston Harbor (CHE), Puget Sound (PUG), and the Neuse River (NRE). Mean DOM concentrations ranged from 100 to 700 µM and dissolved lignin concentrations ranged from ca. 3-30 µg L-1. Overall trends were linear between CDOM measured at 350 nm (a350) and DOC concentration (R2=0.77) and between a350 and lignin (R2=0.87). Intercepts of a350 vs lignin were not significantly different from zero (P=0.43) suggesting that most of the CDOM was terrestrial in nature. Deviations from these regressions were strongest in the Neuse River Estuary, the most eutrophic of the six estuaries studied. After this calibration procedure, fluorescence modeling via parallel factor analysis (PARAFAC) was used to make estimates of terrigenous and planktonic DOC in these estuaries.

Occurrence, distribution, and sources of emerging organic contaminants in tropical coastal sediments of anthropogenically impacted Klang River estuary, Malaysia.

Science.gov (United States)

Omar, Tuan Fauzan Tuan; Aris, Ahmad Zaharin; Yusoff, Fatimah Md; Mustafa, Shuhaimi

2018-06-01

This baseline assessment reports on the occurrence, distribution, and sources of emerging organic contaminants (EOCs) in tropical coastal sediments of anthropogenically impacted Klang River estuary, Malaysia. Bisphenol A was the highest concentration detected at 16.84 ng g -1 dry weight, followed by diclofenac (13.88 ng g -1 dry weight) and E1 (12.47 ng g -1 dry weight). Five compounds, namely, amoxicillin, progesterone, diazinon, bisphenol A, and E1, were found in all sampling stations assessed, and other compounds such as primidone, diclofenac, testosterone, E2, and EE2 were ubiquitously present in sediment samples, with percentage of detection range from 89.04% to 98.38%. Organic carbon content and pH were the important factors controlling the fate of targeted compounds in the tropical estuarine sediment. On the basis of the literature from other studies, the sources of EOCs are thought to be from wastewater treatment plants, domestic/medical waste discharge, livestock activities, industrial waste discharge, and agricultural activities. Copyright © 2018 Elsevier Ltd. All rights reserved.

An assessment of anthropogenic and climatic stressors on estuaries using a spatio-temporal GIS-modelling approach for sustainability: Towamba estuary, southeastern Australia.

Science.gov (United States)

Al-Nasrawi, Ali K M; Hamylton, Sarah M; Jones, Brian G

2018-06-03

Monitoring estuarine ecological-geomorphological dynamics has become a crucial aspect of studying the impacts of climate change and worldwide infrastructure development in coastal zones. Together, these factors have changed the natural eco-geomorphic processes that affect estuarine regimes and comprehensive modelling of coastal resources can assist managers to make appropriate decisions about their sustainable use. This study has utilised Towamba estuary (southeastern NSW, Australia), to demonstrate the value and priority of modelling estuarine dynamism as a measure of the rates and consequences of eco-geomorphic changes. This research employs several geoinformatic modelling approaches over time to investigate and assess how climate change and human activities have altered this estuarine eco-geomorphic setting. Multitemporal trend/change analysis of sediment delivery, shoreline positions and land cover, determined from fieldwork and GIS analysis of remote sensing datasets, shows significant spatio-temporal changes to the elevation and areal extent of sedimentary facies in the Towamba estuary over the past 65 years. Geomorphic growth (~ 2600 m 2 annually) has stabilised the estuarine habitats, particularly within native vegetation, salt marsh and mangrove areas. Geomorphic changes have occurred because of a combination of sediment runoff from the mostly unmodified terrestrial catchment, nearshore processes (ocean dynamics) and human activities. The construction of GIS models, verified with water and sediment samples, can characterise physical processes and quantify changes within the estuarine ecosystem. Such robust models will allow resource managers to evaluate the potential effects of changes to the current coastal ecosystems.

Upstream freshwater and terrestrial sources are differentially reflected in the bacterial community structure along a small Arctic river and its estuary

Directory of Open Access Journals (Sweden)

Aviaja Lyberth Hauptmann

2016-09-01

Full Text Available Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N. Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns.

Upstream Freshwater and Terrestrial Sources Are Differentially Reflected in the Bacterial Community Structure along a Small Arctic River and Its Estuary

Science.gov (United States)

Hauptmann, Aviaja L.; Markussen, Thor N.; Stibal, Marek; Olsen, Nikoline S.; Elberling, Bo; Bælum, Jacob; Sicheritz-Pontén, Thomas; Jacobsen, Carsten S.

2016-01-01

Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N). Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns. PMID:27708629

Mercury in sediments of Ulhas estuary

Digital Repository Service at National Institute of Oceanography (India)

Ram, A.; Rokade, M.A.; Borole, D.V.; Zingde, M.D.

Hg levels in water, suspended particulate matter and sediment of the Ulhas estuary are under considerable environmental stress due to the indiscriminate release of effluents from a variety of industries including chlor-alkali plants. Concentration...

Monitoring requirements for detecting tidal barrage induced changes to estuary bird populations

International Nuclear Information System (INIS)

Davenport, T.; Jeffers, J.N.R.; North, P.M.; Clark, N.A.; Langston, R.H.W.; Prys-Jones, R.P.

1990-01-01

This study was performed to examine the monitoring requirements for detecting tidal barrage induced changes to estuary bird populations, focussing mainly on the Mersey estuary. The degree of variability in populations between years for a number of species within the Mersey, Dee, Alt and Ribble were ascertained. The number of counts needed each winter, before and after barrage construction, were assessed. The percentage charge detectable for species was predicted. One east coast estuary (the Wash) was investigated for comparison of the effects of influences of severe weather. (UK)

Spatial patterns of pharmaceuticals and wastewater tracers in the Hudson River Estuary.

Science.gov (United States)

Cantwell, Mark G; Katz, David R; Sullivan, Julia C; Shapley, Daniel; Lipscomb, John; Epstein, Jennifer; Juhl, Andrew R; Knudson, Carol; O'Mullan, Gregory D

2018-06-15

The widespread use of pharmaceuticals by human populations results in their sustained discharge to surface waters via wastewater treatment plants (WWTPs). In this study, 16 highly prescribed pharmaceuticals were quantified along a 250 km transect of the Hudson River Estuary and New York Harbor to describe their sources and spatial patterns. Sampling was conducted over two dry weather periods in May and July 2016, at 72 sites which included mid-channel and nearshore sites, as well as locations influenced by tributaries and WWTP outfalls. The detection frequency of the study pharmaceuticals was almost identical between the May and July sampling periods at 55% and 52%, respectively. Six pharmaceuticals were measurable at 92% or more of the sites during both sampling periods, illustrating their ubiquitous presence throughout the study area. Individual pharmaceutical concentrations were highly variable spatially, ranging from non-detect to 3810 ng/L during the study. Major factors controlling concentrations were proximity and magnitude of WWTP discharges, inputs from tributaries and tidal mixing. Two compounds, sucralose and caffeine, were evaluated as tracers to identify wastewater sources and assess pharmaceutical behavior. Sucralose was useful in identifying wastewater inputs to the river and concentrations showed excellent correlations with numerous pharmaceuticals in the study. Caffeine-sucralose ratios showed potential in identifying discharges of untreated wastewater occurring during a combined sewage overflow event. Many of the study pharmaceuticals were present throughout the Hudson River Estuary as a consequence of sustained wastewater discharge. Whereas some concentrations were above published effects levels, a more complete risk assessment is needed to understand the potential for ecological impacts due to pharmaceuticals in the Hudson River Estuary. Published by Elsevier Ltd.

Parameterization of mixing by secondary circulation in estuaries

Science.gov (United States)

Basdurak, N. B.; Huguenard, K. D.; Valle-Levinson, A.; Li, M.; Chant, R. J.

2017-07-01

Eddy viscosity parameterizations that depend on a gradient Richardson number Ri have been most pertinent to the open ocean. Parameterizations applicable to stratified coastal regions typically require implementation of a numerical model. Two novel parameterizations of the vertical eddy viscosity, based on Ri, are proposed here for coastal waters. One turbulence closure considers temporal changes in stratification and bottom stress and is coined the "regular fit." The alternative approach, named the "lateral fit," incorporates variability of lateral flows that are prevalent in estuaries. The two turbulence parameterization schemes are tested using data from a Self-Contained Autonomous Microstructure Profiler (SCAMP) and an Acoustic Doppler Current Profiler (ADCP) collected in the James River Estuary. The "regular fit" compares favorably to SCAMP-derived vertical eddy viscosity values but only at relatively small values of gradient Ri. On the other hand, the "lateral fit" succeeds at describing the lateral variability of eddy viscosity over a wide range of Ri. The modifications proposed to Ri-dependent eddy viscosity parameterizations allow applicability to stratified coastal regions, particularly in wide estuaries, without requiring implementation of a numerical model.

Historical Relationships Between Research and Resource Management in the Apalachicola River Estuary.

Science.gov (United States)

Livingston, Robert J

1991-11-01

further complicate the biological relationships of the Apalachicola system. The management of a river-dominated estuary should be based on protection and control of freshwater sources, nutrients, and organic matter with a minimization of physical alterations that often lead to increased salinity stratification and the associated loss of the nursery function of the estuary. There is growing evidence that changes in upland characteristics and within-system habitat alterations are associated with changes in nutrient distributions and salinity relationships and that such changes can have serious impacts on estuarine systems. Issues involving basic changes in estuarine productivity and associated food webs are far more important than those involving species diversity in the management of such resources. Processes such as nutrient flow and salinity alteration underlie the very basis of estuarine productivity and usefulness. Over the past decade, there has been a gradual reduction in the importance of research as an integral part of the planning and management process in the Apalachicola system. This regional trend follows a national pattern. Dredging effects on the river and bay have gone on without effective challenge even though such activities are damaging productive habitats of the system. The once influential Apalachicola oyster fishery remains in disarray following a series of natural disasters and poor management practices. There is a growing problem with the deliberate obstruction of the generation and use of scientific data to determine management policies by various state and federal agencies. The substitution of public relations activities for the development of needed scientific information concerning factors such as the importance of sustained freshwater input to estuaries is further evidence that even the most elaborate and well-conceived management plans can be reversed by political manipulations and short-sighted bureaucratic policies. © 1991 by the Ecological

The dynamics of a frictionally-dominated Amazonian estuary

Directory of Open Access Journals (Sweden)

Nils Edvin Asp

2012-09-01

Full Text Available 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.A hidrodinâmica, morfologia e sedimentologia do estuário do Taperaçu foram investigadas. Este é um entre vários estuários do litoral amazônico que integram a maior extensão contínua de manguezais do mundo, apresentando uma descarga de água doce muito reduzida, atípica para a região. Os resultados revelam grandes bancos arenosos que ocupam em grande parte a porção central do estuário. Areias muito finas e bem selecionadas de origem marinha prevalecem. Fases de enchente mais curtas, com velocidades de corrente substancialmente mais altas, são observadas na por

Anthropogenic Carbon Pump in an Urbanized Estuary

Science.gov (United States)

Park, J. H.; Yoon, T. K.; Jin, H.; Begum, M. S.

2015-12-01

The importance of estuaries as a carbon source has been increasingly recognized over the recent decades. However, constraining sources of CO2 evasion from urbanized estuaries remains incomplete, particularly in densely populated river systems receiving high loads of organic carbon from anthropogenic sources. To account for major factors regulating carbon fluxes the tidal reach of the Han River estuary along the metropolitan Seoul, characterization of organic carbon in the main stem and major urban tributaries were combined with continuous, submersible sensor measurements of pCO2 at a mid-channel location over a year and continuous underway measurements using a submersible sensor and two equilibrator sytems across the estuarine section receiving urban streams. Single-site continuous measurements exhibited large seasonal and diurnal variations in pCO2, ranging from sub-ambient air levels to exceptionally high values approaching 10,000 ppm. Diurnal variations of pCO2 were pronounced in summer and had an inverse relationship with dissolved oxygen, pointing to a potential role of day-time algal consumption of CO2. Cruise measurements displayed sharp pCO2 pulses along the confluences of urban streams as compared with relatively low values along the upper estuary receiving low-CO2 outflows from upstream dams. Large downstream increases in pCO2, concurrent with increases in DOC concentrations and fluorescence intensities indicative of microbially processed organic components, imply a translocation and subsequent dilution of CO2 carried by urban streams and/or fast transformations of labile C during transit along downstream reaches. The unique combination of spatial and temporal continuous measurements of pCO2 provide insights on estuarine CO2 pulses that might have resulted from the interplay between high loads of CO2 and organic C of anthropogenic origin and their priming effects on estuarine microbial processing of terrigenous and algal organic matter.

Benthic studies in south Gujarat estuaries

Digital Repository Service at National Institute of Oceanography (India)

Govindan, K.; Varshney, P.K.; Desai, B.N.

Benthic biomass and faunal composition in relation to various environmental conditions of the four South Gujarat estuaries namely the Auranga, Ambika, Purna and Mindola were studied and compared. Mean population density of benthos in Auranga, Ambika...

Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

Science.gov (United States)

Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

2016-01-01

Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

Biogeochemical budgets for Tapi Estuary

Digital Repository Service at National Institute of Oceanography (India)

Bapardekar, M.V.; DeSousa, S.N.; Zingde, M.D.

sup(-1) comes from the wastes. Chemical fertilizers are used in the basin at the rate of 113 kg.ha sup(-1). During the dry season the salinity in the estuary decreases progressively in the upstream direction form an average 32.53 psu at the mouth to 0...

High porewater exchange in a mangrove-dominated estuary revealed from short-lived radium isotopes

Science.gov (United States)

Sadat-Noori, Mahmood; Santos, Isaac R.; Tait, Douglas R.; Reading, Michael J.; Sanders, Christian J.

2017-10-01

We hypothesise that mangroves play an important role in groundwater exchange processes in sub-tropical and tropical estuarine waters. To investigate this, multiple high resolution time series measurements of radium across a tidal estuary (Coffs Creek, NSW, Australia) were performed as well as a spatial survey in both bottom and surface layers. Results from the spatial survey revealed increasing radium concentrations in parts of the estuary surrounded by mangroves. The average radium concentration in estuary areas lined with mangroves was 2.5 times higher than the average concentration at the mouth of the estuary and 6.5-fold higher than upstream freshwater areas. Additionally, the area enriched in radium coincided with low dissolved oxygen concentrations, implying that porewater exchange may drive anoxia. A radium mass balance model based on 223Ra and 224Ra isotopes at different sections of the estuary confirmed higher porewater exchange rates from areas fringed with mangrove vegetation. Estimated porewater exchange rates were 27.8 ± 5.3 and 13.6 ± 2.1 cm d-1 (0.8 ± 0.1 and 0.4 ± 0.1 m3 s-1) based on 223Ra and 224Ra isotopes, respectively. The average saline porewater exchange was ∼ 10-fold larger than the upstream surface freshwater inputs to the estuary. We suggest that mangrove environments within subtropical estuaries are hotspots for porewater exchange due to the complex belowground structure of crab burrows and the effect of tidal pumping. Because porewater exchange releases carbon and nitrogen from coastal sediments, development and modification of mangrove areas in subtropical estuaries have a significant effect on coastal biogeochemical cycles.

Ecosystem responses to extreme natural events: impacts of three sequential hurricanes in fall 1999 on sediment quality and condition of benthic fauna in the Neuse River Estuary, North Carolina.

Science.gov (United States)

Balthis, W Leonard; Hyland, Jeffrey L; Bearden, Daniel W

2006-08-01

A study was conducted in November 1999 to assess sediment quality and condition of benthic fauna in the Neuse River Estuary (NRE), North Carolina, USA, following the passage of three Atlantic hurricanes during the two months prior. Samples for analysis of macroinfauna (>0.5 mm sieve size), chemical contamination of sediments, and other abiotic environmental variables (salinity, dissolved oxygen, pH, depth, sediment granulometry) were collected at 20 sites from the mouth of the Neuse River at Pamlico Sound to approximately 90 km upstream. Results were compared to those obtained from the same area in July 1998 using similar protocols. Depressed salinity, caused by extreme rainfall and associated high freshwater flow, persisted throughout much of the estuary, which had experienced periods of water-column stratification and hypoxia of underlying waters. Fifteen of the 20 sites, representing 299 km2 (76% of the survey area), also showed signs of benthic stress based on a multi-metric benthic index of biotic integrity (B-IBI). Benthic impacts included reductions in the abundance, diversity, and numbers of species and shifts in taxonomic composition, with a notable increase in dominance of the opportunistic polychaete Mediomastus ambiseta as other former dominant species declined. There was no significant increase in the extent of chemical contamination compared to pre-hurricane conditions. Storm-related reductions in dissolved oxygen and salinity were the more likely causes of the observed benthic impacts, though it was not possible, based on these results, to separate storm effects from seasonal changes in the benthos and annual episodes of summer anoxia and hypoxia.

Functional diversity of fish in estuaries at a global extent

OpenAIRE

Rita P Vasconcelos; Sébastien Villéger; François Guilhaumon

2015-01-01

Biodiversity is currently viewed as a framework encompassing multiple facets of the variety of life, including taxonomic and functional aspects. Species richness and composition of fish assemblages in estuaries is defined by global to local processes acting on community colonization. The present study further investigates how biodiversity of fish assemblages varies among estuaries globally, by simultaneously analysing taxonomic and functional richness and diversity of assemblages. A comprehen...

Estudos higiênicos sôbre os crustáceos e moluscos da Baía de Guanabara (Rio de Janeiro

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Lejeune Pacheco Henriques de Oliveira

1944-04-01

Full Text Available Revisão da literatura médica sôbre higiene de crustáceos e moluscos marinhos. Intoxicações por elementos extranhos às carnes de crustáceos e moluscos: por sais de cobre, vegetais tóxicos; estranho e chumbo nas conservas de crustáceos; botulismo. Putrefação de ostras e doenças de ostras provocadas por cogumelos; crustáceos e moluscos guardados em geladeiras bolorentas. Lista das espécies de moluscos comestíveis da Bahia de Guanabara. Lista das espécies de crustáceos comestíveis da Bahia de Guanabara. Veiculação de micro-organismos patogênicos ao homem por intermédio das carnes de crustáceos e de moluscos: veiculação do vibrião colérico, dos bacilos tíficos e paratíficos e de germes do grupo coli e do gênero Proteus. Vitalidade dos bacilos tíficos nas ostras. Listas dos moluscos veiculadores dos agentes causadores das febres tíficas e paratíficas. Conceitos antigos e modernos sõbre intoxicações por crustáceos; partidas de crustáceos salubres ou não conforme o local de venda. Estudos experimentais sôbre a "talassina" princípio tóxico existente em alguns crustáceos. "Mitilotoxina", intoxicações por mexilhões e outros acidentes incriminados aos moluscos. Enterotoxina estavfilocócica em ostras. Métodos de determinação da salubridade dos moluscos; verificações nas ostras brasileiras. Depuração dos crustáceos pelas soluções cloradas. Estabulação de caranguejos denominados vulgarmente de "guaiamus" e "ussás".Recording main medical publication on Hygiene of Mollusca and Crustacea. Food-poisoning. Decomposing oysters, and shell-fish sickness by fungi. Catalogue of eatable Crustacea and Mollusca of Rio de Janeiro. Significance of Mollusca and Crustacea in the spread of diseases. Longevity of Vibrio comma, Eberthella typhosa, Salmonella schottmuelleri, Salmonella paratiphi. Escherichia coli in oysters, Microorganisms in marked oysters. Comparison old written papers with moderns publications on food

A Study of Sedimentation at the River Estuary on the Change of Reservoir Storage

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Iskahar

2018-01-01

Full Text Available Estuary of the river that leads to the reservoir has characteristics include: relatively flat, there is a change in the increase of wet cross-sectional area and backwater. The backwater will cause the flow velocity to be reduced, so that the grains of sediment with a certain diameter carried by the flow will settle in the estuary of the river. The purpose of this research is to know the distribution and sedimentation pattern at the river estuary that leads to the reservoir with the change of water level in the reservoir storage, so the solution can be found to remove / reduce sediment before entering the reservoir. The method used is the experimental, by making the physical model of the river estuary leading to the reservoir. This study expects a solution to reduce sedimentation, so that sedimentation can be removed / minimized before entering the reservoir. This research tries to apply bypass channel to reduce the sedimentation at the river estuary. Bypass channels can be applied to overcome sedimentation at the river estuary, but in order for the sediment to be removed optimally, it is necessary to modify the mouth of bypass channel and channel angle.

Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

OpenAIRE

Shaha, Dinesh Chandra; Cho, Yang-Ki

2016-01-01

Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. ...

Turning the Tide: Estuaries Shaped by Channel-Shoal Interactions, Eco-engineers and Inherited Landscapes

Science.gov (United States)

Kleinhans, M. G.; Braat, L.; Leuven, J.; Baar, A. W.; van der Vegt, M.; Van Maarseveen, M. C. G.; Markies, H.; Roosendaal, C.; van Eijk, A.

2015-12-01

Estuaries exhibit correlations between inlet dimensions, tidal prism and intertidal area, but to what extent estuary planform shape and shoal patterns resulted from biomorphological processes or from inherited conditions such as coastal plain and drowned valley dimensions remains unclear. We explore the hypothesis that mud flats and vegetation as a self-formed lateral confinement have effects analogous to that of river floodplain on braided versus meandering river patterns. Here we use the Delft3D numerical model and a novel tidal flume setup, the Metronome, to create estuaries from idealized initial conditions, with and without mud supply at the fluvial boundary. Experimental mud was simulated by crushed nutshell. Both the numerical and experimental estuaries were narrower with increasing mud, and had a lower degree of channel braiding. The experimental estuaries developed meanders at the river boundary with floodplain developing on the pointbar whereas cohesionless cases were more dynamic.

Long-term changes in primary production and mineralization of organic matter in the Neva Estuary (Baltic Sea)

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Golubkov, Sergey; Golubkov, Mikhail; Tiunov, Alexei; Nikulina, Vera

2017-07-01

The Neva Estuary situated in the eastern part of the Gulf of Finland is one of the largest estuaries of the Baltic Sea. At present, heavy nutrient and organic matter loading, mainly from the Neva River and point sources in the upper estuary are the most serious environmental problem for the Neva Estuary and adjacent parts of the eastern Gulf of Finland. Long-term studies of mid-summer primary production and mineralization of organic matter were conducted in upper and middle parts of the Neva Estuary. A considerable increase of production and biomass of phytoplankton was observed in the middle part of the estuary during the last decades mainly due to an increase in biomass of cyanobacteria. However, they are mostly concentrated in the upper water layers and only a small part of them reached the near bottom water layers and may be used as a food by zoobenthos. The mineralization of organic matter in the water column was twice higher than primary production that indicates the importance of allochthonous organic matter in the carbon budget of the both parts of the estuary. The carbon isotope signature of seston and most of the zoobenthic species in the upper part of the estuary was close to the signature of allochthonous carbon leaking from watershed (- 27‰). Higher values of δ13C of seston in the upper mix layer of the Middle estuary indicate intensive primary production in mid-summer. The carbon isotopic signature of zoobenthos in this part of the estuary was also in general lower than in the Neva Bay reflected higher importance of autochthonous organic matter in food webs of the estuary.

An assessment of tidal energy potential. The Lima estuary

Energy Technology Data Exchange (ETDEWEB)

Trigo-Teixeira, A. [Department of Civil Engineering and Architecture, Instituto Superior Tecnico, Lisbon Technical University, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Rebordao, I. [WW Consulting Engineers, Laveiras, Caxias 2760-032 (Portugal)

2009-07-01

A hydrodynamic model was set up for the Lima estuary (Portugal) and a preliminary assessment of the strength of tidal currents to produce tidal energy was made. To calibrate the model results were compared with measured data, and the model tuned to reproduce water levels and currents in several locations within the estuary. The data was acquired with ADCPs, during a field campaign that was planed to cover a spring-neap tide cycle, in October 2006. The Advanced Circulation Model - ADCIRC was forced with the most important harmonic constituents present in the ocean tide signal. Upstream, in the river boundary, the discharge was taken from hydrographs. The wetting and drying tool was also applied and a detailed bathymetry was considered, since there are areas in the domain where salt marshes occur, drying out at low tide. The tidal currents potential were assessed for a scenario of tidal forcing only, without any river discharge. The lower estuary is occupied by the port infrastructure and navigation channels which conflicts with any kind of equipment installation. Values of the currents and water depths given by the model indicate that some places in the main channel of the middle estuary, might be interesting to install micro turbines in the future, depending on the evolution of the requirements of this technology.

Thermodynamics of saline and fresh water mixing in estuaries

Science.gov (United States)

Zhang, Zhilin; Savenije, Hubert H. G.

2018-03-01

The mixing of saline and fresh water is a process of energy dissipation. The freshwater flow that enters an estuary from the river contains potential energy with respect to the saline ocean water. This potential energy is able to perform work. Looking from the ocean to the river, there is a gradual transition from saline to fresh water and an associated rise in the water level in accordance with the increase in potential energy. Alluvial estuaries are systems that are free to adjust dissipation processes to the energy sources that drive them, primarily the kinetic energy of the tide and the potential energy of the river flow and to a minor extent the energy in wind and waves. Mixing is the process that dissipates the potential energy of the fresh water. The maximum power (MP) concept assumes that this dissipation takes place at maximum power, whereby the different mixing mechanisms of the estuary jointly perform the work. In this paper, the power is maximized with respect to the dispersion coefficient that reflects the combined mixing processes. The resulting equation is an additional differential equation that can be solved in combination with the advection-dispersion equation, requiring only two boundary conditions for the salinity and the dispersion. The new equation has been confronted with 52 salinity distributions observed in 23 estuaries in different parts of the world and performs very well.

Pu and 137Cs in the Yangtze River estuary sediments: distribution and source identification.

Science.gov (United States)

Liu, Zhiyong; Zheng, Jian; Pan, Shaoming; Dong, Wei; Yamada, Masatoshi; Aono, Tatsuo; Guo, Qiuju

2011-03-01

Pu isotopes and (137)Cs were analyzed using sector field ICP-MS and γ spectrometry, respectively, in surface sediment and core sediment samples from the Yangtze River estuary. (239+240)Pu activity and (240)Pu/(239)Pu atom ratios (>0.18) shows a generally increasing trend from land to sea and from north to south in the estuary. This spatial distribution pattern indicates that the Pacific Proving Grounds (PPG) source Pu transported by ocean currents was intensively scavenged into the suspended sediment under favorable conditions, and mixed with riverine sediment as the water circulated in the estuary. This process is the main control for the distribution of Pu in the estuary. Moreover, Pu is also an important indicator for monitoring the changes of environmental radioactivity in the estuary as the river basin is currently the site of extensive human activities and the sea level is rising because of global climate changes. For core sediment samples the maximum peak of (239+240)Pu activity was observed at a depth of 172 cm. The sedimentation rate was estimated on the basis of the Pu maximum deposition peak in 1963-1964 to be 4.1 cm/a. The contributions of the PPG close-in fallout Pu (44%) and the riverine Pu (45%) in Yangtze River estuary sediments are equally important for the total Pu deposition in the estuary, which challenges the current hypothesis that the riverine Pu input was the major source of Pu budget in this area.

Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

Science.gov (United States)

Oestreich, W. K.; Ganju, N. K.; Pohlman, J. W.; Suttles, S. E.

2016-02-01

Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM), due to the ease of in situ fDOM sensor measurements. Fluorescence must be converted to CDOM absorbance for use in light attenuation calculations. However, this CDOM-fDOM relationship varies among and within estuaries. We quantified the variability in this relationship within three estuaries along the mid-Atlantic margin of the eastern United States: West Falmouth Harbor (MA), Barnegat Bay (NJ), and Chincoteague Bay (MD/VA). Land use surrounding these estuaries ranges from urban to developed, with varying sources of nutrients and organic matter. Measurements of fDOM (excitation and emission wavelengths of 365 nm (±5 nm) and 460 nm (±40 nm), respectively) and CDOM absorbance were taken along a terrestrial-to-marine gradient in all three estuaries. The ratio of the absorption coefficient at 340 nm (m-1) to fDOM (QSU) was higher in West Falmouth Harbor (1.22) than in Barnegat Bay (0.22) and Chincoteague Bay (0.17). The CDOM : fDOM absorption ratio was variable between sites within West Falmouth Harbor and Barnegat Bay, but consistent between sites within Chincoteague Bay. Stable carbon isotope analysis for constraining the source of dissolved organic matter (DOM) in West Falmouth Harbor and Barnegat Bay yielded δ13C values ranging from -19.7 to -26.1 ‰ and -20.8 to -26.7 ‰, respectively. Concentration and stable carbon isotope mixing models of DOC (dissolved organic carbon) indicate a contribution of 13C-enriched DOC in the estuaries. The most likely source of 13C-enriched DOC for the systems we investigated is Spartina cordgrass. Comparison of DOC source to CDOM : f

Morphology and modern sedimentary deposits of the macrotidal Marapanim Estuary (Amazon, Brazil)

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Araújo da Silva, Cléa; Souza-Filho, Pedro Walfir M.; Rodrigues, Suzan W. P.

2009-03-01

The northern Brazilian coast, east of the Amazon River is characterized by several macrotidal estuarine systems that harbor large mangrove areas with approximately 7600 km 2. The Marapanim Estuary is influenced by macrotidal regime with moderate waves influence. Morphologic units were investigated by using remote sensing images (i.e., Landsat-7 ETM+, RADARSAT- 1 Wide and SRTM) integrated with bathymetric data. The modern sedimentary deposits were analyzed from 67 cores collected by Vibracore and Rammkersonde systems. Analysis of morphology and surface sedimentary deposits of the Marapanim River reveal they are strongly influenced by the interaction of tidal, wave and fluvial currents. Based on these processes it was possible to recognize three distinct longitudinal facies zonation that revels the geological filling of a macrotidal estuary. The estuary mouth contain fine to medium marine sands strongly influenced by waves and tides, responsible for macrotidal sandy beaches and estuarine channel development, which are characterized by wave-ripple bedding and longitudinal cross-bedding sands. The estuary funnel is mainly influenced by tides that form wide tidal mudflats, colonized by mangroves, along the estuarine margin, with parallel laminations, lenticular bedding, root fragments and organic matter lenses. The upstream estuary contains coarse sand to gravel of fluvial origin. Massive mud with organic matter lenses, marks and roots fragments occur in the floodplain accumulates during seasonal flooding providing a slowly aggrading in the alluvial plain. This morphologic and depositional pattern show easily a tripartite zonation of a macrotidal estuary, that are in the final stage of filling.

Three-dimensional Modeling of Tidal Hydrodynamics in the San Francisco Estuary

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Edward S. Gross

2010-01-01

Full Text Available Simulations of circulation in the San Francisco Estuary were performed with the three-dimensional TRIM3D hydrodynamic model using a generic length scale turbulence closure. The model was calibrated to reproduce observed tidal elevations, tidal currents, and salinity observations in the San Francisco Estuary using data collected during 1996-1998, a period of high and variable freshwater flow. It was then validated for 1994-1995, with emphasis on spring of 1994, a period of intensive data collection in the northern estuary. The model predicts tidal elevations and tidal currents accurately, and realistically predicts salinity at both the seasonal and tidal time scales. The model represents salt intrusion into the estuary accurately, and therefore accurately represents the salt balance. The model’s accuracy is adequate for its intended purposes of predicting salinity, analyzing gravitational circulation, and driving a particle-tracking model. Two applications were used to demonstrate the utility of the model. We estimated the components of the longitudinal salt flux and examined their dependence on flow conditions, and compared predicted salt intrusion with estimates from two empirical models.

Threshold values and management options for nutrients in a catchment of a temperate estuary with poor ecological status

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K. Hinsby

2012-08-01

Full Text Available Intensive farming has severe impacts on the chemical status of groundwater and streams and consequently on the ecological status of dependent ecosystems. Eutrophication is a widespread problem in lakes and marine waters. Common problems are hypoxia, algal blooms, fish kills, and loss of water clarity, underwater vegetation, biodiversity and recreational value. In this paper we evaluate the nitrogen (N and phosphorus (P concentrations of groundwater and surface water in a coastal catchment, the loadings and sources of N and P, and their effect on the ecological status of an estuary. We calculate the necessary reductions in N and P loadings to the estuary for obtaining a good ecological status, which we define based on the number of days with N and P limitation, and the corresponding stream and groundwater threshold values assuming two different management options. The calculations are performed by the combined use of empirical models and a physically based 3-D integrated hydrological model of the whole catchment. The assessment of the ecological status indicates that the N and P loads to the investigated estuary should be reduced to levels corresponding to 52 and 56% of the current loads, respectively, to restore good ecological status. Model estimates show that threshold total N (TN concentrations should be in the range of 2.9 to 3.1 mg l⁻¹ in inlet freshwater (streams to Horsens estuary and 6.0 to 9.3 mg l⁻¹ in shallow aerobic groundwater (∼ 27–41 mg l⁻¹ of nitrate, depending on the management measures implemented in the catchment. The situation for total P (TP is more complex, but data indicate that groundwater threshold values are not needed. The stream threshold value for TP to Horsens estuary for the selected management options is 0.084 mg l⁻¹. Regional climate models project increasing winter precipitation and runoff in the investigated region resulting in increasing runoff and

Mapping ecosystem services in a Great Lakes estuary supports local decision-making

Science.gov (United States)

Estuaries of the Laurentian Great Lakes provide a concentrated supply of ecosystem goods and services from which humans benefit. As long-term centers of human activity, most estuaries of the Great Lakes and have a legacy of chemical contamination, degraded habitats, and non-point...

Modeling Diel Oxygen Dynamics and Ecosystem Metabolism in a Shallow, Eutrophic Estuary

Science.gov (United States)

Weeks Bay is a shallow eutrophic estuary that exhibits frequent summertime diel-cycling hypoxia and periods of dissolved oxygen (DO) oversaturation during the day. Diel DO dynamics in shallow estuaries like Weeks Bay are complex, and may be influenced by wind forcing, vertical an...

Short-term tidal asymmetry inversion in a macrotidal estuary (Beira, Mozambique)

Science.gov (United States)

Nzualo, Teodósio N. M.; Gallo, Marcos N.; Vinzon, Susana B.

2018-05-01

The distortion of the tide in estuaries, bays and coastal areas is the result of the generation of overtides due to the non-linear effects associated with friction, advection, and the finite effects of the tidal amplitude in shallow waters. The Beira estuary is classified as macrotidal, with a large ratio of S2/M2. Typical tides ranges from 6 m and 0.8 m, during springs and neaps tides, respectively. As a consequence of this large fortnightly tidal amplitude difference and the estuarine morphology, asymmetry inversions occur. Two types of tidal asymmetries were investigated in this paper, one considering tidal duration asymmetry (time difference between rising and falling tide) and the other, related to tidal velocity asymmetry (unequal magnitudes of flood and ebb peaks currents). In the Beira estuary when we examine the tidal duration asymmetry, flood dominance is observed during spring tide periods (negative time difference between rising and falling tide), while ebb dominance appears during neap tides (positive time difference between rising and falling tide). A 2DH hydrodynamic model was implemented to analyze this asymmetry inversion. The model was calibrated with water-level data measured at the Port of Beira and current data measured along the estuary. The model was run for different scenarios considering tidal constituents at the ocean boundary, river discharge and the morphology of the estuary. River discharge did not show significant effects on the tidal duration asymmetry. Through comparison of the scenarios, it was shown that the incoming ocean tide at the boundary has an ebb-dominant asymmetry, changing to flood-dominant only during spring tides due to the effect of shoaling and friction within the estuary. During neap tides, the propagation occurs mainly in the channels, and ebb dominance remains. The interplay between the estuary morphodynamics was thus identified and the relation between tidal duration asymmetry and tidal velocity asymmetry was

Ecological effects of climate change on salt marsh wildlife: a case study from a highly urbanized estuary

Science.gov (United States)

Thorne, Karen M.; Takekawa, John Y.; Elliott-Fisk, Deborah L.

2012-01-01

Coastal areas are high-risk zones subject to the impacts of global climate change, with significant increases in the frequencies of extreme weather and storm events, and sea-level rise forecast by 2100. These physical processes are expected to alter estuaries, resulting in loss of intertidal wetlands and their component wildlife species. In particular, impacts to salt marshes and their wildlife will vary both temporally and spatially and may be irreversible and severe. Synergistic effects caused by combining stressors with anthropogenic land-use patterns could create areas of significant biodiversity loss and extinction, especially in urbanized estuaries that are already heavily degraded. In this paper, we discuss current ideas, challenges, and concerns regarding the maintenance of salt marshes and their resident wildlife in light of future climate conditions. We suggest that many salt marsh habitats are already impaired and are located where upslope transgression is restricted, resulting in reduction and loss of these habitats in the future. In addition, we conclude that increased inundation frequency and water depth will have negative impacts on the demography of small or isolated wildlife meta-populations as well as their community interactions. We illustrate our points with a case study on the Pacific Coast of North America at San Pablo Bay National Wildlife Refuge in California, an area that supports endangered wildlife species reliant on salt marshes for all aspects of their life histories.

Site-specific probabilistic ecological risk assessment of a volatile chlorinated hydrocarbon-contaminated tidal estuary.

Science.gov (United States)

Hunt, James; Birch, Gavin; Warne, Michael St J

2010-05-01

Groundwater contaminated with volatile chlorinated hydrocarbons (VCHs) was identified as discharging to Penrhyn Estuary, an intertidal embayment of Botany Bay, New South Wales, Australia. A screening-level hazard assessment of surface water in Penrhyn Estuary identified an unacceptable hazard to marine organisms posed by VCHs. Given the limitations of hazard assessments, the present study conducted a higher-tier, quantitative probabilistic risk assessment using the joint probability curve (JPC) method that accounted for variability in exposure and toxicity profiles to quantify risk (delta). Risk was assessed for 24 scenarios, including four areas of the estuary based on three exposure scenarios (low tide, high tide, and both low and high tides) and two toxicity scenarios (chronic no-observed-effect concentrations [NOEC] and 50% effect concentrations [EC50]). Risk (delta) was greater at low tide than at high tide and varied throughout the tidal cycle. Spatial distributions of risk in the estuary were similar using both NOEC and EC50 data. The exposure scenario including data combined from both tides was considered the most accurate representation of the ecological risk in the estuary. When assessing risk using data across both tides, the greatest risk was identified in the Springvale tributary (delta=25%)-closest to the source area-followed by the inner estuary (delta=4%) and the Floodvale tributary (delta=2%), with the lowest risk in the outer estuary (delta=0.1%), farthest from the source area. Going from the screening level ecological risk assessment (ERA) to the probabilistic ERA changed the risk from unacceptable to acceptable in 50% of exposure scenarios in two of the four areas within the estuary. The probabilistic ERA provided a more realistic assessment of risk than the screening-level hazard assessment. Copyright (c) 2010 SETAC.

Does traditional shellfishing affect foraging by waders? The case of the Tagus estuary (Portugal)

Science.gov (United States)

Dias, Maria P.; Peste, Filipa; Granadeiro, José P.; Palmeirim, Jorge M.

2008-03-01

Estuarine intertidal flats are often exploited by humans and waders since they provide food, particularly shellfish. This raises important conservation issues. Waders can be affected by shellfishing activities in multiple ways, such as a reduction of the available shellfish, disturbance by the presence of shellfishers on their feeding areas, and changes in micro-habitat, due to sediment reworking. In this study we quantified the impact of traditional shellfishing on waders in the Tagus estuary. Particular attention was given to hand-raking of clams Scrobicularia plana, which constitutes most of the consumed food by waders. Shellfishers did not cause a relevant depletion of clams for waders; they removed less than 0.3% of its total production and focused on size classes that were usually not taken by birds. Hand-raking caused temporary changes in the vertical distribution and availability of invertebrate prey in the sediment. However, this did not affect the bird's feeding rates, presumably because prey availability remained above the threshold at which intake rates are expected to decline. The presence of shellfishers in the birds foraging areas potentially affects waders by keeping them away from foraging areas, but even the most affected species lost less than 10% of their foraging grounds due to this factor. Overall, we conclude that the current low harvesting levels of shellfishing are compatible with the preservation of the estuary as a key site for waders. Nevertheless, simulations showed that traditional shellfishing could have much greater potential to affect waders through disturbance than through prey removal. The results for the Tagus show that even small harvest rates, representing a negligible loss of food for waders and potentially considered sustainable by shellfish managers, could have a great impact on waders due to increased disturbance. This effect of disturbance likely occurs in most estuaries and should be taken into consideration when planning

The relative importance of oceanic nutrient inputs for Bass Harbor Marsh Estuary at Acadia National Park, Maine

Science.gov (United States)

Huntington, Thomas G.; Culbertson, Charles W.; Fuller, Christopher; Glibert, Patricia; Sturtevant, Luke

2014-01-01

The U.S. Geological Survey and Acadia National Park (ANP) collaborated on a study of nutrient inputs into Bass Harbor Marsh Estuary on Mount Desert Island, Maine, to better understand ongoing eutrophication, oceanic nutrient inputs, and potential management solutions. This report includes the estimation of loads of nitrate, ammonia, total dissolved nitrogen, and total dissolved phosphorus to the estuary derived from runoff within the watershed and oceanic inputs during summers 2011 and 2012. Nutrient outputs from the estuary were also monitored, and nutrient inputs in direct precipitation to the estuary were calculated. Specific conductance, water temperature, and turbidity were monitored at the estuary outlet. This report presents a first-order analysis of the potential effects of projected sea-level rise on the inundated area and estuary volume. Historical aerial photographs were used to investigate the possibility of widening of the estuary channel over time. The scope of this report also includes analysis of sediment cores collected from the estuary and fringing marsh surfaces to assess the sediment mass accumulation rate. Median concentrations of nitrate, ammonium, and total dissolved phosphorus on the flood tide were approximately 25 percent higher than on the ebb tide during the 2011 and 2012 summer seasons. Higher concentrations on the flood tide suggest net assimilation of these nutrients in biota within the estuary. The dissolved organic nitrogen fraction dominated the dissolved nitrogen fraction in all tributaries. The median concentration of dissolved organic nitrogen was about twice as high on the on the ebb tide than the flood tide, indicating net export of dissolved organic nitrogen from the estuary. The weekly total oceanic inputs of nitrate, ammonium, and total dissolved phosphorus to the estuary were usually much larger than inputs from runoff or direct precipitation. The estuary was a net sink for nitrate and ammonium in most weeks during both

Molecular characterization of autochthonous hydrocarbon utilizing ...

African Journals Online (AJOL)

Prof. Ogunji

crude oil-impacted sites at Bodo community, Ogoniland in the Niger Delta were isolated using ... potential solution to such environmental problems (Akinde et al., 2012). .... communities from mangrove sediments in Guanabara Bay, Brazil. Res.

Bacterial domination over Archaea in ammonia oxidation in a monsoon-driven tropical estuary

Digital Repository Service at National Institute of Oceanography (India)

Vipindas, P.V.; Anas, A.; Jasmin, C.; Lallu, K.R.; Fausia, K.H.; Balachandran, K.K.; Muraleedharan, K.R.; Nair, S.

Autotrophic ammonia oxidizing microorganisms,which are responsible for the rate-limiting step of nitrification in most aquatic systems, have not been studied in tropical estuaries. Cochin estuary (CE) is one of the largest, productive, and monsoon...

Organic carbon deliveries and their flow related dynamics in the Fitzroy estuary

International Nuclear Information System (INIS)

Ford, Phillip; Tillman, Pei; Robson, Barbara; Webster, Ian T.

2005-01-01

The Fitzroy estuary (Queensland, Australia) receives large, but highly episodic, river flows from a catchment (144,000 km 2 ) which has undergone major land clearing. Large quantities of suspended sediments, and particulate and dissolved organic carbon are delivered. At peak flows, δ 13 C (-21.7 ± 0.8%o) and C/N (14.8 ± 1.3) of the suspended solids indicate that the particulate organic material entering the estuary is principally soil organic carbon. At the lower beginning flows the particulate organic matter comes from in-stream producers (δ 13 C = -26%o). The DOC load is about 10 times the POC load. Using the inverse method, budgets for POC and DOC were constructed for high and low flows. Under high flows, only a small portion of the POC and DOC load is lost in the estuary. Under dry season (low flow) conditions the estuary is a sink for DOC, but remains a source of POC to the coastal waters

Water and suspended sediment dynamics in the Sungai Selangor estuary

International Nuclear Information System (INIS)

Abdul Kadir Ishak; Kamarudin Samuding; Nazrul Hizam Yusoff

2000-01-01

Observations of salinity, temperature, suspended sediment concentration (SSC) and tidal current velocity were made in the lower and along the longitudinal axis sungai Selangor estuary over near-spring cycles. The variations of these parameters at the measurement stations and along the channel are presented to illustrate the water and sediment dynamics in the estuary. The results shows that the Sungai Selangor estuary changes from a partially-mixed type during neaps to a well-mixed one during springs. promoted by stronger tidal energy during the higher tidal ranges. The strong neap density stratification is also promoted by the high river discharges during the measurement period maximum concentration of suspended sediment 2000 mg,'/) occurs during maximum current velocities both during flood and ebb. The maximum salinity was achieved during high water slack but the salt water was totally flushed out of estuary during low water springs. The longitudinal axis measurement indicates that a partially-developed zone of turbidity maximum with a sediment concentration over 1000 mg/l was observed at the limit of salt water intrusion in salinity range less than 1 ppt. Tidal pumping as oppose to the estuarine circulation is the more dominant factor in the maximum formation as the salt water is totally excluded at low water. (author)

Human impacts on morphodynamic thresholds in estuarine systems

Science.gov (United States)

Wang, Z. B.; Van Maren, D. S.; Ding, P. X.; Yang, S. L.; Van Prooijen, B. C.; De Vet, P. L. M.; Winterwerp, J. C.; De Vriend, H. J.; Stive, M. J. F.; He, Q.

2015-12-01

Many estuaries worldwide are modified, primarily driven by economic gain or safety. These works, combined with global climate changes heavily influence the morphologic development of estuaries. In this paper, we analyze the impact of human activities on the morphodynamic developments of the Scheldt Estuary and the Wadden Sea basins in the Netherlands and the Yangtze Estuary in China at various spatial scales, and identify mechanisms responsible for their change. Human activities in these systems include engineering works and dredging activities for improving and maintaining the navigation channels, engineering works for flood protection, and shoreline management activities such as land reclamations. The Yangtze Estuary is influenced by human activities in the upstream river basin as well, especially through the construction of many dams. The tidal basins in the Netherlands are also influenced by human activities along the adjacent coasts. Furthermore, all these systems are influenced by global changes through (accelerated) sea-level rise and changing weather patterns. We show that the cumulative impacts of these human activities and global changes may lead to exceeding thresholds beyond which the morphology of the tidal basins significantly changes, and loses its natural characteristics. A threshold is called tipping point when the changes are even irreversible. Knowledge on such thresholds or tipping points is important for the sustainable management of these systems. We have identified and quantified various examples of such thresholds and/or tipping points for the morphodynamic developments at various spatial and temporal scales. At the largest scale (mega-scale) we consider the sediment budget of a tidal basin as a whole. A smaller scale (macro-scale) is the development of channel structures in an estuary, especially the development of two competing channels. At the smallest scale (meso-scale) we analyze the developments of tidal flats and the connecting

α-particle radioactivity of hot particles from the Esk estuary

International Nuclear Information System (INIS)

Hamilton, E.I.

1981-01-01

Transuranium radionuclides (Pu, Am and Cm) present in effluents discharged into the north-east Irish Sea by British Nuclear Fuels Limited, Windscale, Cumbria, UK, are found in sediment and biota of the Esk estuary approximately 10 km to the south. The site of the present investigation was at Newbiggin and the materials examined were suspended particulate debris samples at the sea surface, bottom sediments and some forms of biota collected in September 1977. It is shown here that hot particles (defined as small volumes of material emitting α particles recorded in a dielectric detector as dense clusters of tracks from a common origin) found in the estuary are likely to be original effluent debris derived from the processing of Magnox uranium fuel elements and not formed in situ as a result of natural processes common to the estuary. (author)

Sedimentation and erosion trends over 50 years in the macrotidal Gironde estuary

Science.gov (United States)

Sottolichio, Aldo; Hanquiez, Vincent; Arriagada, Joselyn; Jalon-Rojas, Isabel

2017-04-01

Recent studies have emphasized on the drastic morphodynamic evolution of many european urbanized estuaries, which have become more turbid during the XXth century because of human-induced deepening and narrowing. For some systems, the availability of data has allowed detailed analysis of evolution, while for some other estuaries, knowledge remains limited. For the latter, it is difficult to elucidate any effect due to climate change, extreme events or human activities. Among them, the Gironde estuary is a macrotidal funnel-shape system, the largest estuary of Western Europe, and characterized by high levels of turbidity. Despite numerous investigations on sedimentary processes carried out in this estuary in the past, there is poor knowledge on the evolution of its morphology and tides over the XXth century. Recently, an investigation on tidal patterns has started in the Garonne tidal river, where it is known that gravel extraction during the sixties has deeply modified the mean depth of the channel. In the meantime, there is evidence of a long-term shift of the turbidity maximum in this area, mainly due to a reduction of river flow in the last 40 years. However, for the main estuarine portion, which represents 80% of the total surface, morphology evolution and associated physical processes remain under-investigated. In this study the morphological evolution of the Gironde estuary has been documented and investigated for the first time, based on some bathymetric and tidal data collected from the archives of the port of Bordeaux. Six bathymetric maps covering a period of 50 years, from the 1953 to year 2000 were compared, highlighting areas of accretion and erosion. Results show that the zone of maximum volume of deposited sediment has migrated continuously towards the upstream portion of the estuary, which is coherent with the intensification of the low river flow periods and the upstream shift of the turbidity maximum zone to the riverine sections. In the meantime

Seasonal and tidal influence on the variability of nitrous oxide in the Tagus estuary, Portugal

Directory of Open Access Journals (Sweden)

Célia Gonçalves

2010-11-01

Full Text Available In order to evaluate seasonal and tidal influence on the variability of dissolved nitrous oxide (N2O in the Tagus estuary, Portugal, water sampling was carried out along the salinity gradient (May and November 2006 and during several tidal cycles (February and April 2007 at a fixed site. N2O and other relevant environmental parameters, temperature, salinity, dissolved oxygen and inorganic nitrogen forms (nitrate, nitrite and ammonium were measured. Dissolved N2O concentrations showed strong tidal and seasonal variability, with the highest values occurring in February 2007 (13.7 nM, spring tide and November 2006 (18.4 nM, upper estuary, apparently related to major Tagus river discharge. The existence of N2O sources was noticed in middle estuary. During spring tide, the input from external sources may be augmented by water column nitrification, making this process a contributor to the enhancement of N2O concentration in the estuary. Estimated N2O air-sea fluxes to the atmosphere reached a maximum value of ~10.4 μmol m-2 d-1 in February 2007 during spring tide and in May 2006 in the upper and lower (left bank estuary. Although the Tagus estuary behaves predominantly as a source of atmospheric N2O, it appears to be a weaker source than other, more eutrophic estuaries.

The Guayas Estuary and sea level corrections to calculate flooding areas for climate change scenarios

Science.gov (United States)

Moreano, H. R.; Paredes, N.

2011-12-01

The Guayas estuary is the inner area of the Gulf of Guayaquil, it holds a water body of around 5000 km2 and the Puna island divides the water flow in two main streams : El Morro and Estero Salado Channel (length: 90 Km.) and Jambeli and Rio Guayas Channel (length: 125km.). The geometry of the estuarine system with the behavior of the tidal wave (semidiurnal) makes tidal amplitude higher at the head than at the mouth, whereas the wave crest at the head is delayed from one and a half to two hours from that at the mouth and sea level recorded by gages along the estuary are all different because of the wave propagation and mean sea level (msl) calculated for each gage show differences with that of La Libertad which is the base line for all altitudes on land (zero level). A leveling and calculations were made to correct such differences in a way that all gages (msl) records were linked to La Libertad and this in turn allowed a better estimates of flooding areas and draw them on topographic maps where zero level corresponds to the mean sea level at La Libertad. The procedure and mathematical formulation could be applied to any estuary or coastal area and it is a useful tool to calculate such areas especially when impacts are on people or capital goods and related to climate change scenarios.

Diet and trophic organization of the fish assemblage from the Mamanguape River Estuary, Brazil

OpenAIRE

Medeiros, Aline Paiva Morais de; Xavier, Josias Henrique de Amorim; Rosa, Ierecê Maria de Lucena

2017-01-01

ABSTRACT The present work aims to characterize a fish assemblage from a northeastern Brazilian estuary according to its diet and trophic organization along the estuarine-reef gradient. Sampling was performed at the Mamanguape Estuary, and fishes were collected using three types of nets at seventeen sites, grouped into four regions according to salinity range: reefs and the lower, middle, and upper estuary. The most abundant species were Atherinella brasiliensis, Mugil curema, and Sphoeroides ...

Modelling the transverse distribution of velocity and suspended sediment in tidal estuaries

NARCIS (Netherlands)

Huijts, K.M.H.

2011-01-01

An estuary is a semi-enclosed coastal body of water which has a free connection with the open sea and within which sea water is measurably diluted with fresh water derived from land drainage. Examples are the Western Scheldt River Estuary and the Chesapeake Bay. Within these environments complex

A preliminary fish survey of the estuaries on the southeast coast of ...

African Journals Online (AJOL)

2016-01-01

Jan 1, 2016 ... ABSTRACT. A basic ichthyofaunal and physico-chemical survey of estuaries on the southeast coast of South Africa from Kayser's Beach to Kei Mouth was undertaken during September and October 1996. Twenty-eight (28) estuaries have been identified along this stretch of coastline, and these were ...

Contaminants of emerging concern in a large temperate estuary.

Science.gov (United States)

Meador, James P; Yeh, Andrew; Young, Graham; Gallagher, Evan P

2016-06-01

This study was designed to assess the occurrence and concentrations of a broad range of contaminants of emerging concern (CECs) from three local estuaries within a large estuarine ecosystem. In addition to effluent from two wastewater treatment plants (WWTP), we sampled water and whole-body juvenile Chinook salmon (Oncorhynchus tshawytscha) and Pacific staghorn sculpin (Leptocottus armatus) in estuaries receiving effluent. We analyzed these matrices for 150 compounds, which included pharmaceuticals, personal care products (PPCPs), and several industrial compounds. Collectively, we detected 81 analytes in effluent, 25 analytes in estuary water, and 42 analytes in fish tissue. A number of compounds, including sertraline, triclosan, estrone, fluoxetine, metformin, and nonylphenol were detected in water and tissue at concentrations that may cause adverse effects in fish. Interestingly, 29 CEC analytes were detected in effluent and fish tissue, but not in estuarine waters, indicating a high potential for bioaccumulation for these compounds. Although concentrations of most detected analytes were present at relatively low concentrations, our analysis revealed that overall CEC inputs to each estuary amount to several kilograms of these compounds per day. This study is unique because we report on CEC concentrations in estuarine waters and whole-body fish, which are both uncommon in the literature. A noteworthy finding was the preferential bioaccumulation of CECs in free-ranging juvenile Chinook salmon relative to staghorn sculpin, a benthic species with relatively high site fidelity. Published by Elsevier Ltd.

Environmental features and macrofauna of Kahana Estuary, Oahu, Hawaii

Science.gov (United States)

Maciolek, J.A.; Timbol, A.S.

1981-01-01

Lack of ecological information on Hawaiian estuaries prompted an intensive 2-year study of a small (5.7 ha) stream-mouth estuary on windward Oahu. Water quality and macrofauna were sampled weekly at seven stations. The water mass was strongly stratified vertically except during freshets. Average values for water column temperature and bottom salinity were 23.2°C and 12‰ at the head to 28.3°C and 28‰ at the mouth. Dissolved oxygen saturation in the water column varied from about 50% at night to 140% in the afternoon. Usually, bottom waters were 3–6°C warmer than surface waters and sometimes showed severe oxygen depletion.Macrofauna, collected primarily by seining, consisted mainly of decapod crustaceans (four species of crabs, seven species of shrimps) and fishes (24 species). Other typical estuarine taxons (mollusks, barnacles, polychaetes) were scarce or absent. Diversity increased seaward from 14 species near the estuary head to 29 species near the mouth. Three species of crustaceans and six of fishes were captured at all stations. Most abundant were the native prawn, Macrobrachium grandimanus, and mullet, Mugil cephalus. Perennially resident adults occurred among crustaceans and gobioid fishes; most other fishes were present as juveniles and sporadic adults. Comparisons with other data suggest that more than 50 species of native fishes may occur in Hawaiian estuaries, and that estuarine macrofaunal diversity on oceanic islands is much lower than on continents at similar latitudes.

Worldwide patterns of fish biodiversity in estuaries: Effect of global vs. local factors

Science.gov (United States)

Pasquaud, Stéphanie; Vasconcelos, Rita P.; França, Susana; Henriques, Sofia; Costa, Maria José; Cabral, Henrique

2015-03-01

The main ecological patterns and the functioning of estuarine ecosystems are difficult to evaluate due to natural and human induced complexity and variability. Broad geographical approaches appear particularly useful. This study tested, at a worldwide scale, the influence of global and local variables in fish species richness in estuaries, aiming to determine the latitudinal pattern of species richness, and patterns which could be driven by local features such as estuary area, estuary mouth width, river flow and intertidal area. Seventy one estuarine systems were considered with data obtained from the literature and geographical information system. Correlation tests and generalized linear models (GLM) were used in data analyses. Species richness varied from 23 to 153 fish species. GLM results showed that estuary area was the most important factor explaining species richness, followed by latitude and mouth width. Species richness increased towards the equator, and higher values were found in larger estuaries and with a wide mouth. All these trends showed a high variability. A larger estuary area probably reflects a higher diversity of habitats and/or productivity, which are key features for estuarine ecosystem functioning and biota. The mouth width effect is particularly notorious for marine and diadromous fish species, enhancing connectivity between marine and freshwater realms. The effects of river flow and intertidal area on the fish species richness appear to be less evident. These two factors may have a marked influence in the trophic structure of fish assemblages.

Modelling the occurrence of postflexion stages of a marine estuarine-dependent fish in temperate South African estuaries

Directory of Open Access Journals (Sweden)

Yanasivan Kisten

2017-03-01

Full Text Available 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.

Sedimentation in a river dominated estuary

CSIR Research Space (South Africa)

Cooper, JAG

1993-10-01

Full Text Available The Mgeni Estuary on the wave dominated cast coast of South Africa occupies a narrow, bedrock confined, alluvial valley and is partially blocked at the coast by an elongate sandy barrier. Fluvial sediment extends to the barrier and marine depositon...

Air–Sea CO2 Gas Transfer Velocity in a Shallow Estuary

DEFF Research Database (Denmark)

Mørk, Eva Thorborg; Sørensen, Lise Lotte; Jensen, Bjarne

2014-01-01

The air–sea transfer velocity of CO2(kCO2) was investigated in a shallow estuary in March to July 2012, using eddy-covariance measurements of CO2 fluxes and measured air–sea CO2 partial-pressure differences. A data evaluation method that eliminates data by nine rejection criteria in order......, the transfer velocity in the shallow water estuary was lower than in other coastal waters, possibly a symptom of low tidal amplitude leading to low intensity water turbulence. High transfer velocities were recorded above wind speeds of 5 m s−1 , believed to be caused by early-breaking waves and the large fetch...... (6.5 km) of the estuary. These findings indicate that turbulence in both air and water influences the transfer velocity....

Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

Science.gov (United States)

Oestreich, W.K.; Ganju, Neil K.; Pohlman, John; Suttles, Steven E.

2016-01-01

Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM), due to the ease of in situ fDOM sensor measurements. Fluorescence must be converted to CDOM absorbance for use in light attenuation calculations. However, this CDOM–fDOM relationship varies among and within estuaries. We quantified the variability in this relationship within three estuaries along the mid-Atlantic margin of the eastern United States: West Falmouth Harbor (MA), Barnegat Bay (NJ), and Chincoteague Bay (MD/VA). Land use surrounding these estuaries ranges from urban to developed, with varying sources of nutrients and organic matter. Measurements of fDOM (excitation and emission wavelengths of 365 nm (±5 nm) and 460 nm (±40 nm), respectively) and CDOM absorbance were taken along a terrestrial-to-marine gradient in all three estuaries. The ratio of the absorption coefficient at 340 nm (m−1) to fDOM (QSU) was higher in West Falmouth Harbor (1.22) than in Barnegat Bay (0.22) and Chincoteague Bay (0.17). The CDOM : fDOM absorption ratio was variable between sites within West Falmouth Harbor and Barnegat Bay, but consistent between sites within Chincoteague Bay. Stable carbon isotope analysis for constraining the source of dissolved organic matter (DOM) in West Falmouth Harbor and Barnegat Bay yielded δ13C values ranging from −19.7 to −26.1 ‰ and −20.8 to −26.7 ‰, respectively. Concentration and stable carbon isotope mixing models of DOC (dissolved organic carbon) indicate a contribution of 13C-enriched DOC in the estuaries. The most likely source of 13C-enriched DOC for the systems we investigated is Spartina cordgrass. Comparison of

Nutrient Enrichment in Estuaries from Discharge of Shallow Ground Water, Mt. Desert Island, Maine

Science.gov (United States)

Culbertson, Charles W.; Huntington, Thomas G.; Caldwell, James M.

2007-01-01

Nutrient enrichment from atmospheric deposition, agricultural activities, wildlife, and domestic sources is a concern at Acadia National Park because of the potential problem of water-quality degradation and eutrophication in its estuaries. Water-quality degradation has been observed at the Park?s Bass Harbor Marsh estuary but not in Northeast Creek estuary. Previous studies at Acadia National Park have estimated nutrient inputs to estuaries from atmospheric deposition and surface-water runoff, but the importance of shallow ground water that may contain nutrients derived from domestic or other sources is unknown. Northeast Creek and Bass Harbor Marsh estuaries were studied to (1) identify shallow ground-water seeps, (2) assess the chemistry of the water discharged from selected seeps, and (3) assess the chemistry of ground water in shallow ground-water hyporheic zones. The hyporheic zone is defined here as the region beneath and lateral to a stream bed, where there is mixing of shallow ground water and surface water. This study also provides baseline chemical data for ground water in selected bedrock monitoring wells and domestic wells on Mt. Desert Island. Water samples were analyzed for concentrations of nutrients, wastewater compounds, dissolved organic carbon, pH, dissolved oxygen, temperature and specific conductance. Samples from bedrock monitoring wells also were analyzed for alkalinity, major cations and anions, and trace metals. Shallow ground-water seeps to Northeast Creek and Bass Harbor Marsh estuaries at Acadia National Park were identified and georeferenced using aerial infrared digital imagery. Monitoring included the deployment of continuously recording temperature and specific conductance sensors in the seep discharge zone to access marine or freshwater signatures related to tidal flooding, gradient-driven shallow ground-water flow, or shallow subsurface flow related to precipitation events. Many potential shallow ground-water discharge zones were

Comparative assessment of two agriculturally-influenced estuaries

CSIR Research Space (South Africa)

Lemley, DA

2017-04-01

Full Text Available This study compared the spatio-temporal dynamics in two agriculturally-influenced South African estuaries - Gamtoos and Sundays - to investigate how contrasting hydrological alterations influence physical, chemical and biological responses...

Nursery life of the marine prawn, Metapenaeus dobsoni (Miers) in the Mandovi estuary, along Goa Coast, India

Digital Repository Service at National Institute of Oceanography (India)

Achuthankutty, C.T.

of the estuary. Seasonal variation in abundance was discernible. Initial growth occurred in the shallow region of the estuary bordered by mangroves and later in the deeper waters of the open estuary. Optimum attainable size in the estuarine environment was 50...

Use of glacier river-fed estuary channels by juvenile coho salmon: transitional or rearing habitats?

Science.gov (United States)

Hoem Neher, Tammy D.; Rosenberger, Amanda E.; Zimmerman, Christian E.; Walker, Coowe M.; Baird, Steven J.

2014-01-01

Estuaries are among the most productive ecosystems in the world and provide important rearing environments for a variety of fish species. Though generally considered important transitional habitats for smolting salmon, little is known about the role that estuaries serve for rearing and the environmental conditions important for salmon. We illustrate how juvenile coho salmonOncorhynchus kisutch use a glacial river-fed estuary based on examination of spatial and seasonal variability in patterns of abundance, fish size, age structure, condition, and local habitat use. Fish abundance was greater in deeper channels with cooler and less variable temperatures, and these habitats were consistently occupied throughout the season. Variability in channel depth and water temperature was negatively associated with fish abundance. Fish size was negatively related to site distance from the upper extent of the tidal influence, while fish condition did not relate to channel location within the estuary ecotone. Our work demonstrates the potential this glacially-fed estuary serves as both transitional and rearing habitat for juvenile coho salmon during smolt emigration to the ocean, and patterns of fish distribution within the estuary correspond to environmental conditions.

Decadal-scale Evolution of Sediment Flux in the Aulne Estuary

Science.gov (United States)

Moskalski, S. M.; Deschamps, A.; Floc'h, F.; Verney, R.; Piete, H.; Fromant, G.; Delacourt, C.

2013-12-01

Estuarine sediment transport processes have the potential to evolve over time in response to alterations in various factors both internal and external to the estuary, such as sediment supply, river discharge, tidal forcing, or changes to bathymetry. Changes in sediment transport can affect many estuarine processes (e.g. budgets of sediment-adsorbed contaminants or nutrients) and ecosystem services, such as aquaculture, primary production and the need to dredge shipping channels. Most studies of decadal-scale changes in estuaries focus on geomorphology or bathymetry, or are performed using models calibrated by a limited set of observational studies. Because of the potential for sediment flux to both affect and be affected by geomorphology and bathymetry, observational studies oriented to sediment flux evolution are needed. This study focuses on two intensive observational studies separated by 30 years to quantify change in suspended sediment concentration (SSC) in the Aulne river, a shallow macrotidal estuary in western Brittany. Moored and vessel-mounted acoustic Doppler current profilers and YSIs were deployed over a three-week period in the winter of 2013 to examine hydrodynamic and sediment transport processes. The results of the modern study were compared to a 1977 investigation of currents, suspended sediment concentration, and erosion/deposition. The 1977 study found that SSC during spring tide and average river discharge was less than 30 mg/L near the mouth and above 300 mg/L landward, with near-bottom concentrations in the turbidity maximum zone occasionally greater than 1000 mg/L. SSC was highest during low tide and remained elevated throughout, in the upstream part of the estuary. Sediment deposition was stronger after flood tide due to a longer slack period, which implies landward sediment transport in the estuary. In the 2013 study, near-bottom SSC during spring tide and average river discharge was also highest during low tide, but SSC was above 1000 mg

Changes and variations of polycyclic aromatic hydrocarbon concentrations in fish, barnacles and crabs following an oil spill in a mangrove of Guanabara Bay, Southeast Brazil.

Science.gov (United States)

Soares-Gomes, Abílio; Neves, Roberta L; Aucélio, Ricardo; Van Der Ven, Paulo H; Pitombo, Fábio B; Mendes, Carla L T; Ziolli, Roberta L

2010-08-01

On April 26th, 2005, an accident caused a leak of 60,000L of Diesel Oil Type "B", freighted by train wagons upstream on a mangrove area within Guanabara Bay, Southeast Brazil. After the accident, samples from animals with different biological requirements were collected in order to monitor polycyclic aromatic hydrocarbons concentrations for the following 12months. Sessile, mobile, carnivorous, omnivorous, organic detritus feeders, planktivorous and suspension feeders were some of the attributes compared. Concentrations of PAHs did not vary in relation to different dietary habits and the best response was from the sessile suspensivorous barnacles. A background level of <50microgkg(-1) was suggested based on the reference site and on values observed in the following months after the accident. The highest values of PAH concentrations were observed in barnacles in the first month immediately after the spill, decreasing to background levels after few months. Barnacles are suggested as a sentinel species. Copyright 2010 Elsevier Ltd. All rights reserved.

Simulated Sampling of Estuary Plankton

Science.gov (United States)

Fortner, Rosanne W.; Jenkins, Deborah Bainer

2009-01-01

To find out about the microscopic life in the valuable estuary environment, it is usually necessary to be near the water. This dry lab offers an alternative, using authentic data and a simulation of plankton sampling. From the types of organisms found in the sample, middle school students can infer relationships in the biological and physical…

Food Webs in an Estuary.

Science.gov (United States)

Dunne, Barbara B.

The Maryland Marine Science Education Project has produced a series of mini-units in marine science education for the junior high/middle school classroom. This unit focuses on food chains in an estuary. Although the unit specifically treats the Chesapeake Bay, it may be adapted for use with similar estuarine systems. In addition, the unit may be…

Understanding the Influence of Retention Basin on Tidal Dynamics in Tidal Estuaries

Science.gov (United States)

Kumar, Mohit; Schuttelaars, Henk; Roos, Pieter

2014-05-01

Both the tidal motion and suspended sediment concentration (SSC) in tidal embayments and estuaries are influenced by anthropogenic (e.g. deepening ) and natural changes. An example of such an estuary is the Ems estuary, situated on the border of the Netherlands and Germany. The mean tidal range towards the end of the Ems estuary has increased from 1.5m in the 1950s to more than 3m in the 1990s while the suspended concentration has increased by a factor 10. To possibly reduce these negative effects, the construction of retention basin(s) (RB) is considered. In this contribution, the influence of location and geometry of RBs on tidal dynamics and SSC is investigated. For this purpose, a three-dimensional semi-analytic idealized model is developed. This model is an extension of the model proposed by Winant (2007) to arbitrary domain and realistic bathymetry with partial slip boundary condition at the bottom. The sea surface elevation (SSE) is calculated numerically using a finite element method. Next, the three-dimensional velocities are calculated by combining the analytically calculated vertical profiles and the gradients of the SSE which are obtained numerically. Firstly, the influence of a RB on the tidal dynamics in an infinitely long, rectangular, frictionless estuary is considered. The SSE decreases when the RB is located between a node and a landward antinode, consistent with the work of Alebregtse et al. (2013). Secondly, an estuary of finite length is connected to a sea. By varying the width of the sea, not only the effect of the distance of the RB to the landward end plays a role, but also the distance to the open sea becomes important. Finally, we discuss the influence of a RB on the tidal motion and initial sediment transport, considering the Ems estuary with realistic bathymetry. Results show that the SSE at the landward end of the Ems estuary decreases for all locations of the RBs. This decrease is most pronounced for the RB which is closest to the end

Tritium in the Savannah River Estuary and adjacent marine waters

International Nuclear Information System (INIS)

Hayes, D.W.

1978-01-01

The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing, and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is 5 pCi/ml, whereas other rivers in the southeastern United States average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the River and from sea water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary, respectively

Carbon Transformations and Source - Sink Dynamics along a River, Marsh, Estuary, Ocean Continuum

Science.gov (United States)

Anderson, I. C.; Crosswell, J.; Czapla, K.; Van Dam, B.

2017-12-01

Estuaries, the transition zone between land and the coastal ocean, are highly dynamic systems in which carbon sourced from watersheds, marshes, atmosphere, and ocean may be transformed, sequestered, or exported. The net fate of carbon in estuaries, governed by the interactions of biotic and physical drivers varying on spatial and temporal scales, is currently uncertain because of limited observational data. In this study, conducted in a temperate, microtidal, and shallow North Carolina USA estuary, carbon exchanges via river, tributary, and fringing salt marsh, air-water fluxes, sediment C accumulation, and metabolism were monitored over two-years, with sharply different amounts of rainfall. Air-water CO2 fluxes and metabolic variables were simultaneously measured in channel and shoal by conducting high-resolution surveys at dawn, dusk and the following dawn. Marsh CO2 exchanges, sediment C inputs, and lateral exports of DIC and DOC were also measured. Carbon flows between estuary regions and export to the coastal ocean were calculated by quantifying residual transport of DIC and TOC down-estuary as flows were modified by sources, sinks and internal transformations. Variation in metabolic rates, CO2, TOC and DIC exchanges were large when determined for short time and limited spatial scales. However, when scaled to annual and whole estuarine scales, variation tended to decrease because of counteracting metabolic rates and fluxes between channel and shoal or between seasons. Although overall salt marshes accumulated OC, they were a negligible source of DIC and DOC to the estuary, and net inputs of C to the marsh were mainly derived from sediment OC. These results, as observed in other observational studies of estuaries, show that riverine input, light, temperature and metabolism are major controls on carbon cycling. Comparison of our results with other types of estuaries varying in depth, latitude, and nutrification demonstrates large discrepancies underscoring the

Testing a 1-D Analytical Salt Intrusion Model and the Predictive Equation in Malaysian Estuaries

Science.gov (United States)

Gisen, Jacqueline Isabella; Savenije, Hubert H. G.

2013-04-01

Little is known about the salt intrusion behaviour in Malaysian estuaries. Study on this topic sometimes requires large amounts of data especially if a 2-D or 3-D numerical models are used for analysis. In poor data environments, 1-D analytical models are more appropriate. For this reason, a fully analytical 1-D salt intrusion model, based on the theory of Savenije in 2005, was tested in three Malaysian estuaries (Bernam, Selangor and Muar) because it is simple and requires minimal data. In order to achieve that, site surveys were conducted in these estuaries during the dry season (June-August) at spring tide by moving boat technique. Data of cross-sections, water levels and salinity were collected, and then analysed with the salt intrusion model. This paper demonstrates a good fit between the simulated and observed salinity distribution for all three estuaries. Additionally, the calibrated Van der Burgh's coefficient K, Dispersion coefficient D0, and salt intrusion length L, for the estuaries also displayed a reasonable correlations with those calculated from the predictive equations. This indicates that not only is the salt intrusion model valid for the case studies in Malaysia but also the predictive model. Furthermore, the results from this study describe the current state of the estuaries with which the Malaysian water authority in Malaysia can make decisions on limiting water abstraction or dredging. Keywords: salt intrusion, Malaysian estuaries, discharge, predictive model, dispersion

Mixing and flushing time scales in the Azhikode Estuary, southwest coast of India

Digital Repository Service at National Institute of Oceanography (India)

Revichandran, C.; Pylee, A.

Flushing time scales of the Azhikode Estuary, Kerala, India showed pronounced dry season and wet season signals as well as large inter-annual variation. Cumulative flushing time of the estuary varies from 4.8 tide cycles in April to 1.22 tide cycles...

Carbon monoxide apparent quantum yields and photoproduction in the Tyne estuary

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A. Stubbins

2011-03-01

Full Text Available Carbon monoxide (CO apparent quantum yields (AQYs are reported for a suite of riverine, estuarine and sea water samples, spanning a range of coloured dissolved organic matter (CDOM sources, diagenetic histories, and concentrations (absorption coefficients. CO AQYs were highest for high CDOM riverine samples and almost an order of magnitude lower for low CDOM coastal seawater samples. CO AQYs were between 47 and 80% lower at the mouth of the estuary than at its head. Whereas, a conservative mixing model predicted only 8 to 14% decreases in CO AQYs between the head and mouth of the estuary, indicating that a highly photoreactive pool of terrestrial CDOM is lost during estuarine transit. The CDOM absorption coefficient (a at 412 nm was identified as a good proxy for CO AQYs (linear regression r² > 0.8; n = 12 at all CO AQY wavelengths studied (285, 295, 305, 325, 345, 365, and 423 nm and across environments (high CDOM river, low CDOM river, estuary and coastal sea. These regressions are presented as empirical proxies suitable for the remote sensing of CO AQYs in natural waters, including open ocean water, and were used to estimate CO AQY spectra and CO photoproduction in the Tyne estuary based upon annually averaged estuarine CDOM absorption data. A minimum estimate of annual CO production was determined assuming that only light absorbed by CDOM leads to the formation of CO and a maximum limit was estimated assuming that all light entering the water column is absorbed by CO producing photoreactants (i.e. that particles are also photoreactive. In this way, annual CO photoproduction in the Tyne was estimated to be between 0.99 and 3.57 metric tons of carbon per year, or 0.004 to 0.014% of riverine dissolved organic carbon (DOC inputs to the estuary. Extrapolation of CO photoproduction rates to estimate total DOC photomineralisation indicate that less than 1% of DOC inputs are removed via photochemical processes during

Impacts of sea cucumber farming on biogeochemical characteristics in the Yellow River estuary, Northern China

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Fu, Jing; Yokoyama, Hisashi; Cui, Baoshan; Zhou, Jin; Yan, Jiaguo; Ma, Xu; Shibata, Shozo

2017-02-01

To investigate the potential environmental effects of pond farming for Apostichopus japonicas in Yellow River estuary, we examined discrepancies of distance-based typical pollution indicators (TOC, TN, NO3-, NH4+, NO2- and PO43-) and biochemical tracers (δ13C and δ15N) in water column and sediment, as well as dietary characteristics of dominant macrobenthos between farming and non-farming areas. The results revealed that studied variables in water column showed no uniform spatial differences. Meanwhile, those in sediment displayed similar decrease tendencies from farming pond to the adjacent tidal flat, which was considered to represent the environmental effects of farming. Biochemical tracers (δ13C and δ15N) in both water column and sediment confirmed the origin of organic matters from the aquaculture waste. The detectable dispersion distance of aquaculture waste was restricted to an area within 50 m distance as determined by most variables in sediment (TOC, TN, NO3- and NH4+), particularly by C:N ratio and δ13C with which origins of the wastes were traced. Bayesian mixing models indicated that in the farming area BMA had a larger contribution, while POM(marine) showed a smaller contribution to the diets of Helice tridens and Macrophthalmus abbreviates compared to those in the non-farming area. The overall results showed that pond farming for Apostichopus japonicus in the Yellow River estuary altered the local environment to a certain extent. For methodological consideration, sediment biogeochemical characteristics as a historical recorder much more effectively reflected aquaculture waste accumulation, and stable isotope approaches are efficient in tracing the origin and extent of various allogenous sources.

Characterization of estuary use by Nisqually Hatchery Chinook based on Otolith analysis

Science.gov (United States)

Lind-Null, Angie M.; Larsen, Kim A.; Reisenbichler, Reg

2008-01-01

INTRODUCTION The Nisqually Fall Chinook population is one of 27 stocks in the Puget Sound evolutionarily significant unit listed as threatened under the federal Endangered Species Act (ESA). Preservation and extensive restoration of the Nisqually delta ecosystem are planned to assist in recovery of the stock. A pre-restoration baseline including life history types, estuary residence time, growth rates, and habitat use are needed to evaluate the potential response of hatchery and wild Chinook salmon to restoration. Otolith analysis has been selected as a means to examine Chinook salmon life history, growth, and residence in the Nisqually estuary. Over time, the information from the otolith analyses will be used to: 1) determine if estuary restoration actions cause changes to the population structure (i.e. frequency of the different life history trajectories) for Nisqually River Chinook, 2) compare pre- and post- restoration residence times and growth rates, 3) suggest whether estuary restoration yields substantial benefits for Chinook salmon through (1) and (2), and 4) compare differences in habitat use between hatchery and wild Chinook to further protect ESA listed stock. Otoliths are calcium carbonate structures in the inner ear that grow in proportion to the overall growth of the fish. Daily growth increments can be measured so date and fish size at various habitat transitions can be back-calculated. Careful analysis of otolith microstructure can be used to determine the number of days that a fish resided in the estuary as a juvenile (increment counts), size at entrance to the estuary, size at egress, and the amount that the fish grew while in the estuary. Juvenile hatchery Chinook salmon are generally released as smolts that move quickly through the delta with much shorter residence times than for many wild fish and are not dependent on the delta as nursery habitat (Myers and Horton 1982; Mace 1983; Levings et al. 1986). The purpose of this study is to use and

Marine geology of the St. Lawrence Estuary

Energy Technology Data Exchange (ETDEWEB)

St-Onge, Guillaume [Canada Research Chair in Marine Geology, Institut des sciences de la mer de Rimouski (ISMER) and GEOTOP Research Center, 310 allee des Ursulines, Rimouski, Quebec, G5L 3A1 (Canada); Duchesne, Mathieu J [Geological Survey of Canada, Quebec Division, 490 de la Couronne, Quebec City, Quebec, G1K 9A9 (Canada); Lajeunesse, Patrick, E-mail: guillaume_st-onge@uqar.qc.ca [Departement de geographie and Centre d' etudes nordiques, Universite Laval, Quebec City, Quebec, G1V 0A6 (Canada)

2011-05-15

The St. Lawrence Estuary, Eastern Canada, contains a very thick (>450 m) Quaternary sedimentary sequence. The results from recently conducted geophysical surveys in conjunction with piston coring indicate that these sediments were deposited under very high sedimentation rates, sometimes as high as {approx}30 m/ka during the last deglaciation. Results also reveal evidence of large submarine landslides during the Holocene, changes in sedimentation rates and the significant role of submarine canyons and channels to transfer sediments from the coast to the deeper marine environment. Finally, this paper highlights the presence of more than 1900 pockmarks on the seafloor of the St. Lawrence Estuary and discusses their possible origins: active hydrocarbon seeps in the Laurentian Channel and biogenic gas seepage on the northwestern shoulder of the Laurentian Channel.