scholarly journals MACROBENTHIC COMMUNITIES IN A TEMPERATE URBAN ESTUARY OF HIGH DOMINANCE AND LOW DIVERSITY: MONTEVIDEO BAY (URUGUAY)

2015 ◽  
Vol 30 (1) ◽  
pp. 9
Author(s):  
P. Muniz ◽  
N. Venturini
Keyword(s):  
Organic Matter ◽  
Bottom Water ◽  
Organic Matter Content ◽  
Matter Content ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Small Surface ◽  
La Plata ◽  
Urban Estuary ◽  
Low Diversity

The macrobenthic subtidal community was studied between April 1997 and April 1998 in Montevideo bay, an urban estuary located in the fluvio marine system of the Río de la Plata (Uruguay) that receives a variety of industrial and sewage inputs. Monthly surveys were carried out at ten sampling stations where sediment samples were taken with a manual corer and analysed for granulometric parameters, organic matter content, chlorophyll a and phaeopigments content, redox potential, and macrobenthic fauna. The area presented high organic matter content in its sediments and several regions of the bottom were anoxic during a large part of the sampling period. The benthic macrofauna was dominated, both in numbers as well as in biomass, by the small surface deposit-feeder gastropod Heleobia cf. australis. Cluster analysis, Multidimensional Scaling and Canonical Correspondence Analysis revealed that the study area could be divided in two well-defined regions with different environmental characteristics and different faunal composition. The dissolved oxygen content in the bottom water and variables related to it were the most important factors in explaining the patterns of the benthic communities. At the phylum level, the meta-analysis of “production” showed a high disturbance status for all stations. The inner region, the most affected by anthropogenic activities, was the most compromised environmentally and biologically, and was characterised by a very low diversity and abundance, reduced conditions in the sediments and low oxygenated bottom water. In more external places of the bay, on the other hand, perhaps due to their location at a greater distance from the sources of organic material and in a region with higher hydrodynamic energy, the conditions for the development of benthic fauna were more favourable. Spatial and temporal faunistic patterns observed and their possible causes are analysed and discussed in relation to the natural and anthropogenic factors that act in this coastal ecosystem. Comunidades macrobentónicas en un estuario urbano templado de alta dominancia y baja diversidad: Bahía de Montevideo (Uruguay) Una comunidad macrobentónica submareal fue estudiada entre abril de 1997 y abril de 1998 en la Bahía de Montevideo, un estuario urbano localizado en el sistema marino fluvial del Río de la Plata (Uruguay) que recibe una variedad de descargas industriales y de alcantarillado. Se llevaron a cabo muestreos mensuales en diez estaciones donde se tomaron muestras de sedimento utilizando un nucleador y a estas les fueron analizadas los parámetros granulométricos, el contenido de materia orgánica, el contenido de clorofila a y de feopigmentos, potencial redox y fauna macrobentónica. El área presentó un alto contenido de materia orgánica en sus sedimentos y muchas regiones del fondo mostraron ser anóxicas durante una gran parte del mismo período. La fauna macrobentónica fue dominada en número y biomasa por los pequeños gasterópodosHeleobia cf. australis. Los análisis de conglomerados, de escala multidimensional y de correspondencia canónica revelaron que el área de estudio podría ser dividida en dos regiones bien definidas con diferentes características ambientales y composiciones faunísticas diferentes. El contenido de oxígeno disuelto en agua de fondo y las variables realcionadas con ella fueron los factores más importatntes en explicar los patrones de las comunidades bentónicas. Al nivel phylum, los meta análisis de la “producción” mostraron un alto estatus de perturbación y biológica que fue caracterizada por baja diversidad y abundancia, condiciones reducidas y agua de fondo poco oxigenada. Por otra parte, en los sitios más externos de la bahía, debido quizas a su localización a una gran distancia de las fuentes de materia orgánica con una alta energía hidrodinámica, las condiciones para el desarrollo de la fauna bentónica fueron favorables. Los patrones faunísticos espaciales y temporales observados y sus posibles causas fueron analizados y discutidos en relación con los factores naturales y antropogénicos que actúan sobre este ecosistema costero.

scholarly journals Linking patterns of freshwater discharge and sources of organic matter within the Río de la Plata estuary and adjacent marshes

2017 ◽  
Vol 68 (9) ◽  
pp. 1704 ◽  
Author(s):  
Leandro Bergamino ◽  
Mark Schuerch ◽  
Adriana Tudurí ◽  
Silvina Carretero ◽  
Felipe García-Rodríguez
Keyword(s):  
Organic Matter ◽  
Surface Sediments ◽  
Sediment Cores ◽  
Freshwater Discharge ◽  
C3 Plants ◽  
Estuarine System ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata ◽  
Matter Transport

We investigated carbon isotopic ratios (δ13C) v. carbon to nitrogen (C : N) ratios for surface sediments throughout a large estuarine system (Río de la Plata, RdlP), combined with sediment cores from adjacent marshes to infer main carbon sources. We also evaluated the influence of the El Niño–Southern Oscillation (ENSO) and associated high freshwater-discharge events on the organic-matter transport within the estuary. The isotopic pattern in surface sediments of the RdlP showed the upper reaches to be influenced by riverine particulate matter (δ13C range: –24 to –26‰). Similarly, in the sediment cores from marshes of the upper reaches, δ13C values decreased from –24‰ in ancient sediments to –28‰ in recent sediments, reflecting an increased contribution of organic matter from land, including C3 plants and freshwater phytoplankton, during the past 50 years. However, the lower reaches represent a depositional environment of marine algae (δ13C range: –21 to –23‰), with no influence of detritus from adjacent marshes, indicating minor erosion of the marshes in the lower reaches operating as carbon-sink habitats. Our isotopic analysis showed that the transport and deposition of terrigenous organic matter within the RdlP and adjacent marsh habitat appear to be both temporally and spatially linked to hydrology patterns.

scholarly journals The Relationship between Mollusks and Oxygen Concentrations in Todos Santos Bay, Baja California, Mexico

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
J. Gabriel Kuk-Dzul ◽  
Victoria Díaz-Castañeda
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Bottom Water ◽  
Organic Matter Content ◽  
Oxygen Depletion ◽  
Matter Content ◽  
The Other ◽  
Natural Conditions ◽  
The Relationship ◽  
Oxygen Concentrations

This study describes the relationship between mollusks, physicochemical properties of seawater, and sediments under natural conditions of low impact. Thirty-nine stations were sampled in October 1994 using a Van Veen grab (0.1 m−2). Temperature, salinity, and dissolved oxygen (DO) concentrations of bottom water were obtained with a CTD. Organic matter content and sediment grain analysis were determined. A total of 836 mollusks were collected. Gastropoda was the most abundant (52%) and diverse class with 27 genera, followed by Bivalvia with eight genera and Scaphopoda with only one genus. According to CCA analysis, dominant mollusks were significantly related with high DO concentrations.Donax,Natica,Acteocina,Bulla,Anachis,Odostomia, andCrucibulumcan be classified as sensitive genera because they were found mainly in high oxygen concentrations (3.1–5.6 mL L−1); on the other hand,Cardiomya,Nuculana,Laevicardium,Chione,Truncatella, andDentaliumcan be classified as tolerant genera (1.0–5.6 mL L−1). Todos Santos Bay hosts a diverse malacological fauna (36 genera); our results show that the dominant genera were mainly related to high dissolved oxygen concentrations. Mollusks can be a useful tool in environmental monitoring programs related with oxygen depletion in coastal areas.

scholarly journals Polychaete assemblage of an impacted estuary, Guanabara Bay, Rio de Janeiro, Brazil

2009 ◽  
Vol 57 (4) ◽  
pp. 287-303 ◽  
Author(s):  
Leonardo Santi ◽  
Marcos Tavares
Keyword(s):  
Organic Matter ◽  
Water Column ◽  
Rainy Season ◽  
Organic Matter Content ◽  
Matter Content ◽  
Total Organic Matter ◽  
Guanabara Bay ◽  
High Biomass ◽  
Hypoxic Conditions ◽  
Low Diversity

Thirty-eight stations were sampled in Guanabara Bay, Rio de Janeiro, Brazil, to assess the spatio-temporal diversity and biomass of sublittoral polychaetes. Samples were collected during the dry (September 2000) and rainy season (May 2001) in shallow sublittoral sediments. The polychaete spatial composition showed a heterogeneous distribution throughout the bay. A negative gradient of diversity and biomass was observed towards the inner parts of the bay and sheltered areas. A wide azoic area was found inside the bay. Some high-biomass and low-diversity spots were found near a sewage-discharge point. In these areas, the polychaete biomass increased after the rainy season. A diversified polychaete community was identified around the bay mouth, with no dramatic changes of this pattern between the two sampling periods. Deposit-feeders were dominant in the entire study area. The relative importance of carnivores and omnivores increased towards the outer sector, at stations with coarse sediment fractions. Guanabara Bay can be divided into three main zones with respect to environmental conditions and polychaete diversity and biomass patterns: A) High polychaete diversity, hydrodynamically exposed areas composed of sandy, oxidized or moderately reduced sediments with normoxic conditions in the water column. B) Low diversity and high biomass of deposit and suspension-feeding polychaete species in the middle part of the bay near continental inflows, comprising stations sharing similar proportions of silt, clay and fine sands. C) Azoic area or an impoverished polychaete community in hydrodynamically low-energy areas of silt and clay with extremely reduced sediments, high total organic matter content and hypoxic conditions in the water column, located essentially from the mid-bay towards the north sector. High total organic matter content and hypoxic conditions combined with slow water renewal in the inner bay seemed to play a key role in the polychaete diversity and biomass. Sedimentation processes and organic load coming from untreated sewage into the bay may have negatively affected the survivorship of the fauna.

scholarly journals SPATIAL AND TEMPORAL VARIATION IN THE PRESENT AND HISTORICAL SEDIMENTARY ORGANIC MATTER WITHIN THE RÍO DE LA PLATA ESTUARY (SOUTH AMERICA) IN RELATION TO THE SALINITY/TURBIDITY GRADIENT / VARIAÇÃO ESPACIAL E TEMPORAL PRESENTE E HISTÓRICA DA MATÉRIA ORGÂNICA SEDIMENTAR NO ESTUÁRIO DO RÍO DE LA PLATA (AMÉRICA DO SUL) EM RELAÇÃO AO GRADIENTE DE SALINIDADE / TURBIDEZ

2018 ◽  
Vol 3 (4) ◽  
pp. 265-279 ◽  
Author(s):  
Adriana Tudurí ◽  
Leandro Bergamino ◽  
Roberto Violante ◽  
José Luis Cavallotto ◽  
Felipe García-Rodríguez
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
South America ◽  
Total Organic Carbon ◽  
Total Nitrogen ◽  
Sedimentary Organic Matter ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata ◽  
Fine Sediments

The aim of this study is to examine sedimentary organic matter sources, spatial distribution and temporal variability in a large estuarine system, the Río de la Plata estuary (South America). For this purpose, this work integrates recent and historical carbon and nitrogen isotopes (δ13C, δ15N), total organic carbon, total nitrogen, C/N ratios and sediment grain size analyses along the Río de la Plata estuary. Principal component analysis based on biogeochemical variables and salinity revealed two main biogeochemical contrasting zones, corresponding to the upper and the lower estuary. Such zones are derived from the density gradient observed at the maximum turbidity zone acting as a physical barrier by trapping fine sediments and controlling primary productivity. As a consequence, sedimentary total organic carbon and total nitrogen increase from upper reaches towards lower reaches to attain maximum values under the turbidity gradient due to the presence of fine sediments. On the other hand, C/N ratios display an opposite trend, with higher values in the upper reaches due to a higher influence of continental organic matter. Moreover, Stable Isotope Analysis in R (SIAR) based on δ13C and δ15N reveals that the main organic matter source to the sediment appears to be the continental particulate organic matter and the estimated percentages of terrestrial allochthonous contribution (C3 plants) indicated a decreased contribution towards the lower reaches. The paleoenvironmental analysis shows a change in the sedimentary organic matter composition since 1970 associated to an increased influence of terrestrial organic matter. This trend is related to an increase in the Paraná River flow, which in turn is related to climatic variability (i.e., the polarity change of the Pacific Decadal Oscillation). ResumoO objetivo deste estudo é estimar fontes de matéria orgânica sedimentar, distribuição espacial e variabilidade temporal num grande sistema estuarino, o estuário do Río de la Plata (América do Sul). Este trabalho integra dados atuais e históricos de isótopos de carbono e nitrogênio (δ13C, δ15N), carbono orgânico total, nitrogênio total, relação C/N e granulometria do sedimento ao longo do estuário do Río de la Plata. A análise de componentes principais baseada em variáveis biogeoquímicas e salinidade revelou duas zonas biogeoquímicas contrastantes, correspondentes ao estuário superior e inferior. Tais zonas são definidas por diferenças no gradiente de densidade na zona de turbidez máxima, o qual atua como uma barreira física, causando o aprisionamento de sedimentos finos e influenciando a produtividade primária. Como conseqüência, o carbono orgânico total sedimentar e o nitrogênio total aumentam dos trechos superiores para os trechos inferiores atingindo valores máximos sob o gradiente de turbidez devido à presença de sedimentos finos. Por outro lado, a razão C/N exibe uma tendência oposta, atingindo valores mais elevados no estuário superior devido a uma maior influência da matéria orgânica continental. Os resultados isotópicos de δ13C e δ15N sugerem que a principal fonte de matéria orgânica para o sedimento é a matéria orgânica particulada continental. A contribuição alóctone terrestre (plantas C3) diminui no estuário inferior. A análise paleoambiental mostra uma mudança na composição da matéria orgânica sedimentar a partir de 1970, causada pelo aumento do fornecimento da matéria orgânica terrestre. Essa tendência está relacionada a um aumento no fluxo do Rio Paraná, na sequência de alterações climáticas relacionadas com a mudança de polaridade da Oscilação Decadal do Pacífico.

HEAVY METAL SPECIATION IN BOTTOM SEDIMENTS OF THE VYSHNEVOLOTSKY RESERVOIR

2018 ◽  
pp. 46-54
Author(s):  
O. A. Lipatnikova
Keyword(s):  
Heavy Metal ◽  
Organic Matter ◽  
Bottom Sediments ◽  
Metal Speciation ◽  
Organic Matter Content ◽  
Water Reservoir ◽  
Matter Content ◽  
Heavy Metal Speciation ◽  
Mobile Forms ◽  
Manganese Hydroxides

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.

Physico-Chemical Properties of Soil Collected from Chandrabhaga River in Kalmeshwar, Nagpur, Maharashtra

2020 ◽  
Vol 07 (02) ◽  
pp. 1-3
Author(s):  
Amita M Watkar ◽  
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Agricultural Land ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Matter Content ◽  
Soil Attributes ◽  
Essential Components ◽  
Agricultural Land Management ◽  
Physical And Chemical

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.

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