Monteiro, Pedro MSRoychoudhury, AN2007-02-072007-06-072007-02-072007-06-072005-10Monteiro, PMS and Roychoudhury, AN. 2005. Spatial characteristics of sediment trace metals in an eastern boundary upwelling retention area (St. Helena Bay, South Africa): A hydrodynamic-biological pump hypothesis. Estuarine, Coastal and Shelf Science, vol 65, 2 January, pp 123-1340272-7714http://hdl.handle.net/10204/1575http://hdl.handle.net/10204/1575St. Helena Bay, is a retention zone located in the southern Benguela upwelling system, and is an important fish nursery. However, it suffers from seasonal bottom water hypoxia causing major economic losses. Anoxic conditions are linked to sulfide fluxes from bottom sediments defined by a high sedimentation rate of organic matter. It is proposed that trace metals may play an important role in alleviating part of the ecological stress by forming sulfide complexes in such systems. A spatially intensive data set of sediment biogeochemical characteristics showed that POC (Particular organic carbon) and trace metals were accumulating in the central zone of the Bay. Furthermore, trace metal concentrations were strongly correlated with both POC and Al. To explain the observed biogeochemical relationships, a hypothesis was proposed, the hypothesis linked the upwelling retention hydrodynamics, primary productivity and sediment trace metal distribution. Trace metals are incorporated into phytoplankton cells in the euphotic zone but rapidly sediment along with particulate organics, on their senescence. Both, the biological pump and the dispersion of particulates are primarily controlled by the hydrodynamics prevalent within St. Helena Bay, which also governs the retention zone in the shadow of one of the major upwelling cells. The dynamics of entrainment-stratification drives the productivity, while a residual cyclonic gyre concentrates the surface productivity within the bay. Bed-shear stresses spatially constrain the accumulation of biogenic organic matter, which governs the trace metal biogeochemistry of the sediments, along a narrow terrigenous mud belt.708945 bytesapplication/pdfenCopyright: 2005 Elsevier Science LtdOrganic carbonUpwelling retention hydrodynamicsSediment ecosystemsRetention ZonesSt. Helena Bay - South AfricaEnvironmental sciencesBenguela upwelling ecosystemArticleMonteiro, P. M., & Roychoudhury, A. (2005). Spatial characteristics of sediment trace metals in an eastern boundary upwelling retention area (St. Helena Bay, South Africa): A hydrodynamic-biological pump hypothesis. http://hdl.handle.net/10204/1575Monteiro, Pedro MS, and AN Roychoudhury "Spatial characteristics of sediment trace metals in an eastern boundary upwelling retention area (St. Helena Bay, South Africa): A hydrodynamic-biological pump hypothesis." (2005) http://hdl.handle.net/10204/1575Monteiro PM, Roychoudhury A. Spatial characteristics of sediment trace metals in an eastern boundary upwelling retention area (St. Helena Bay, South Africa): A hydrodynamic-biological pump hypothesis. 2005; http://hdl.handle.net/10204/1575.TY - Article AU - Monteiro, Pedro MS AU - Roychoudhury, AN AB - St. Helena Bay, is a retention zone located in the southern Benguela upwelling system, and is an important fish nursery. However, it suffers from seasonal bottom water hypoxia causing major economic losses. Anoxic conditions are linked to sulfide fluxes from bottom sediments defined by a high sedimentation rate of organic matter. It is proposed that trace metals may play an important role in alleviating part of the ecological stress by forming sulfide complexes in such systems. A spatially intensive data set of sediment biogeochemical characteristics showed that POC (Particular organic carbon) and trace metals were accumulating in the central zone of the Bay. Furthermore, trace metal concentrations were strongly correlated with both POC and Al. To explain the observed biogeochemical relationships, a hypothesis was proposed, the hypothesis linked the upwelling retention hydrodynamics, primary productivity and sediment trace metal distribution. Trace metals are incorporated into phytoplankton cells in the euphotic zone but rapidly sediment along with particulate organics, on their senescence. Both, the biological pump and the dispersion of particulates are primarily controlled by the hydrodynamics prevalent within St. Helena Bay, which also governs the retention zone in the shadow of one of the major upwelling cells. The dynamics of entrainment-stratification drives the productivity, while a residual cyclonic gyre concentrates the surface productivity within the bay. Bed-shear stresses spatially constrain the accumulation of biogenic organic matter, which governs the trace metal biogeochemistry of the sediments, along a narrow terrigenous mud belt. DA - 2005-10 DB - ResearchSpace DP - CSIR KW - Organic carbon KW - Upwelling retention hydrodynamics KW - Sediment ecosystems KW - Retention Zones KW - St. Helena Bay - South Africa KW - Environmental sciences KW - Benguela upwelling ecosystem LK - https://researchspace.csir.co.za PY - 2005 SM - 0272-7714 T1 - Spatial characteristics of sediment trace metals in an eastern boundary upwelling retention area (St. Helena Bay, South Africa): A hydrodynamic-biological pump hypothesis TI - Spatial characteristics of sediment trace metals in an eastern boundary upwelling retention area (St. Helena Bay, South Africa): A hydrodynamic-biological pump hypothesis UR - http://hdl.handle.net/10204/1575 ER -