The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Dirk Van Maldegem - One of the best experts on this subject based on the ideXlab platform.
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Suspended matter in the Scheldt Estuary
Hydrobiologia, 2005Co-Authors: Margaret S. Chen, Stanislas Wartel, Dirk Van MaldegemAbstract:The Scheldt Estuary is characterised by a specific energy pattern resulting from the interaction of wave energy, tidal energy and river energy. It divides the Estuary into three parts and governs suspended matter transport and distribution pattern. Observation of suspended matter transport shows the existence of three estuarine turbidity maxima (ETM), a marine-dominated ETM in the lower Estuary at the river mouth, a river-dominated ETM in the upper Estuary with suspended matter concentration reaching up to 300 mg/l, and the most important tide-dominated ETM in the middle Estuary with suspended matter concentrations from several hundred milligrams per litre up to a few grams per litre. Resuspension is the dominant phenomenon in this last ETM due to the tidal related bottom scour, which is initiated when a critical erosion velocity of 0.56 m/s is exceeded. An assessment of residual current along the axis of the Estuary shows distinctive pattern between the surface water flow and the near bottom water flow. Also the local morphology of the river, natural or man-made, has a prominent effect on the orientation and strength of the residual currents flowing along either side of the river or river bend. Evaluation of suspended matter concentration in relation to the current flow shows no systematic correlation either because of phenomena as scour lag and settling lag mainly in the middle Estuary, or because of the current independency character of uniform-suspension mainly in the upper and lower Estuary. Quantification of suspended matter load exhibits a net downstream transport from the upper Estuary, a near-equilibrium sustainable status in the middle Estuary and a net upstream transport of suspended matter from the lower Estuary. The characteristic of suspended matter is induced by and is a function of e.g. tidal phase, spring-neap tide, longitudinal and vertical distribution mechanisms, seasons, short and long terms of anthropogenic influence and/or estuarine maintenance. Suspended matter is dominated by complex and cohesive organo-mineral aggregates. It consists of a variable amount of an inorganic fraction (average of 89%) and an organic fraction and occurs largely as flocs, the size of which is remarkably larger in the upper Estuary and smallest within the ETM in the middle Estuary. Independent time series measurements (1990–2000) of suspended matter property show an increasing sand fraction, a decreasing organic matter content, a rise in δ^13C as well as a decrease in water transparency. These independent measurements exhibit coherent consequences of estuarine maintenance operations. Maintenance dredging of the shipping channel and harbours and dumping operation in the Scheldt strengthen marine influence further landward, resulting in a sustained tidal range increment and upstream flow and transport of suspended matter.
Benoit Lebreton - One of the best experts on this subject based on the ideXlab platform.
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origin composition and quality of suspended particulate organic matter in relation to freshwater inflow in a south texas Estuary
Estuarine Coastal and Shelf Science, 2016Co-Authors: Benoit Lebreton, Jennifer Beseres Pollack, Brittany N Blomberg, Terence A Palmer, Leslie Adams, Gael Guillou, Paul A MontagnaAbstract:South Texas has a semi-arid climate with a large interannual variability of freshwater inflows. This study sought to define how changes in freshwater inflow affect the composition, quantity and quality of suspended particulate organic matter (SPOM) in a South Texas Estuary: the Mission-Aransas Estuary. The study was implemented 1.5 months after a large rain event in September 2010 and continued for 10 months of drought conditions. The composition of SPOM originating from rivers, the Gulf of Mexico and the Estuary were determined using stable isotopes (δ 13 C, δ 15 N and δ 34 S). The quantity and quality of SPOM were assessed using organic carbon content, chlorophyll a concentrations and C/chl a ratios. Our results demonstrated that autochthonous phytoplankton was the dominant component of SPOM in the Mission-Aransas Estuary during droughts. Benthic organic matter from local primary producers (i.e., seagrass, salt marsh plants, benthic microalgae) did not influence SPOM composition, either as fresh material or as detritus. A comparison with a positive Estuary (i.e., Sabine-Neches Estuary, TX) indicates that decreases in freshwater inflow may lead to decreases of terrestrial organic matter inputs and to increase the ratio of autochtonous phytoplanktonic material in SPOM. Highlights-Phytoplankton dominate particulate organic matter in the Mission-Aransas Estuary.-Benthic organic matter does not influence particulate organic matter composition.-Organic matter drained by rivers during minor rain events is of very poor quality.
Margaret S. Chen - One of the best experts on this subject based on the ideXlab platform.
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Suspended matter in the Scheldt Estuary
Hydrobiologia, 2005Co-Authors: Margaret S. Chen, Stanislas Wartel, Dirk Van MaldegemAbstract:The Scheldt Estuary is characterised by a specific energy pattern resulting from the interaction of wave energy, tidal energy and river energy. It divides the Estuary into three parts and governs suspended matter transport and distribution pattern. Observation of suspended matter transport shows the existence of three estuarine turbidity maxima (ETM), a marine-dominated ETM in the lower Estuary at the river mouth, a river-dominated ETM in the upper Estuary with suspended matter concentration reaching up to 300 mg/l, and the most important tide-dominated ETM in the middle Estuary with suspended matter concentrations from several hundred milligrams per litre up to a few grams per litre. Resuspension is the dominant phenomenon in this last ETM due to the tidal related bottom scour, which is initiated when a critical erosion velocity of 0.56 m/s is exceeded. An assessment of residual current along the axis of the Estuary shows distinctive pattern between the surface water flow and the near bottom water flow. Also the local morphology of the river, natural or man-made, has a prominent effect on the orientation and strength of the residual currents flowing along either side of the river or river bend. Evaluation of suspended matter concentration in relation to the current flow shows no systematic correlation either because of phenomena as scour lag and settling lag mainly in the middle Estuary, or because of the current independency character of uniform-suspension mainly in the upper and lower Estuary. Quantification of suspended matter load exhibits a net downstream transport from the upper Estuary, a near-equilibrium sustainable status in the middle Estuary and a net upstream transport of suspended matter from the lower Estuary. The characteristic of suspended matter is induced by and is a function of e.g. tidal phase, spring-neap tide, longitudinal and vertical distribution mechanisms, seasons, short and long terms of anthropogenic influence and/or estuarine maintenance. Suspended matter is dominated by complex and cohesive organo-mineral aggregates. It consists of a variable amount of an inorganic fraction (average of 89%) and an organic fraction and occurs largely as flocs, the size of which is remarkably larger in the upper Estuary and smallest within the ETM in the middle Estuary. Independent time series measurements (1990–2000) of suspended matter property show an increasing sand fraction, a decreasing organic matter content, a rise in δ^13C as well as a decrease in water transparency. These independent measurements exhibit coherent consequences of estuarine maintenance operations. Maintenance dredging of the shipping channel and harbours and dumping operation in the Scheldt strengthen marine influence further landward, resulting in a sustained tidal range increment and upstream flow and transport of suspended matter.
Paul A Montagna - One of the best experts on this subject based on the ideXlab platform.
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origin composition and quality of suspended particulate organic matter in relation to freshwater inflow in a south texas Estuary
Estuarine Coastal and Shelf Science, 2016Co-Authors: Benoit Lebreton, Jennifer Beseres Pollack, Brittany N Blomberg, Terence A Palmer, Leslie Adams, Gael Guillou, Paul A MontagnaAbstract:South Texas has a semi-arid climate with a large interannual variability of freshwater inflows. This study sought to define how changes in freshwater inflow affect the composition, quantity and quality of suspended particulate organic matter (SPOM) in a South Texas Estuary: the Mission-Aransas Estuary. The study was implemented 1.5 months after a large rain event in September 2010 and continued for 10 months of drought conditions. The composition of SPOM originating from rivers, the Gulf of Mexico and the Estuary were determined using stable isotopes (δ 13 C, δ 15 N and δ 34 S). The quantity and quality of SPOM were assessed using organic carbon content, chlorophyll a concentrations and C/chl a ratios. Our results demonstrated that autochthonous phytoplankton was the dominant component of SPOM in the Mission-Aransas Estuary during droughts. Benthic organic matter from local primary producers (i.e., seagrass, salt marsh plants, benthic microalgae) did not influence SPOM composition, either as fresh material or as detritus. A comparison with a positive Estuary (i.e., Sabine-Neches Estuary, TX) indicates that decreases in freshwater inflow may lead to decreases of terrestrial organic matter inputs and to increase the ratio of autochtonous phytoplanktonic material in SPOM. Highlights-Phytoplankton dominate particulate organic matter in the Mission-Aransas Estuary.-Benthic organic matter does not influence particulate organic matter composition.-Organic matter drained by rivers during minor rain events is of very poor quality.
Stanislas Wartel - One of the best experts on this subject based on the ideXlab platform.
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Suspended matter in the Scheldt Estuary
Hydrobiologia, 2005Co-Authors: Margaret S. Chen, Stanislas Wartel, Dirk Van MaldegemAbstract:The Scheldt Estuary is characterised by a specific energy pattern resulting from the interaction of wave energy, tidal energy and river energy. It divides the Estuary into three parts and governs suspended matter transport and distribution pattern. Observation of suspended matter transport shows the existence of three estuarine turbidity maxima (ETM), a marine-dominated ETM in the lower Estuary at the river mouth, a river-dominated ETM in the upper Estuary with suspended matter concentration reaching up to 300 mg/l, and the most important tide-dominated ETM in the middle Estuary with suspended matter concentrations from several hundred milligrams per litre up to a few grams per litre. Resuspension is the dominant phenomenon in this last ETM due to the tidal related bottom scour, which is initiated when a critical erosion velocity of 0.56 m/s is exceeded. An assessment of residual current along the axis of the Estuary shows distinctive pattern between the surface water flow and the near bottom water flow. Also the local morphology of the river, natural or man-made, has a prominent effect on the orientation and strength of the residual currents flowing along either side of the river or river bend. Evaluation of suspended matter concentration in relation to the current flow shows no systematic correlation either because of phenomena as scour lag and settling lag mainly in the middle Estuary, or because of the current independency character of uniform-suspension mainly in the upper and lower Estuary. Quantification of suspended matter load exhibits a net downstream transport from the upper Estuary, a near-equilibrium sustainable status in the middle Estuary and a net upstream transport of suspended matter from the lower Estuary. The characteristic of suspended matter is induced by and is a function of e.g. tidal phase, spring-neap tide, longitudinal and vertical distribution mechanisms, seasons, short and long terms of anthropogenic influence and/or estuarine maintenance. Suspended matter is dominated by complex and cohesive organo-mineral aggregates. It consists of a variable amount of an inorganic fraction (average of 89%) and an organic fraction and occurs largely as flocs, the size of which is remarkably larger in the upper Estuary and smallest within the ETM in the middle Estuary. Independent time series measurements (1990–2000) of suspended matter property show an increasing sand fraction, a decreasing organic matter content, a rise in δ^13C as well as a decrease in water transparency. These independent measurements exhibit coherent consequences of estuarine maintenance operations. Maintenance dredging of the shipping channel and harbours and dumping operation in the Scheldt strengthen marine influence further landward, resulting in a sustained tidal range increment and upstream flow and transport of suspended matter.
