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Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system

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dc.contributor.author Pitcher, GC
dc.contributor.author Probyn, TA
dc.contributor.author Du Randt, A
dc.contributor.author Lucas, AJ
dc.contributor.author Bernard, Stewart
dc.contributor.author Evers-King, H
dc.contributor.author Lamont, T
dc.contributor.author Hutchings, L
dc.date.accessioned 2014-07-30T09:20:17Z
dc.date.available 2014-07-30T09:20:17Z
dc.date.issued 2014-04
dc.identifier.citation Pitcher, G.C., Probyn, T.A., Du Randt, A., Lucas, A.J., Bernard, S., Evers-King, H., Lamont, T. and Hutchings, L. 2014. Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system. Journal of Geophysical Research: Oceans, vol. 119(4), pp 2183-2200 en_US
dc.identifier.issn 2169-9275
dc.identifier.uri http://onlinelibrary.wiley.com/doi/10.1002/2013JC009443/abstract
dc.identifier.uri http://hdl.handle.net/10204/7541
dc.description Copyright: 2014 Wiley. This an ABSTRACT ONLY. The definitive version is published in Journal of Geophysical Research: Oceans, vol. 119(4), pp 2183-2200 en_US
dc.description.abstract Acquisition of high resolution time series of water column and bottom dissolved oxygen (DO) concentrations inform the dynamics of oxygen depletion in St Helena Bay in the southern Benguela upwelling system at several scales of variability. The bay is characterized by seasonally recurrent hypoxia (<1.42 ml l(sup-1)) associated with a deep pool of oxygen-depleted water and episodic anoxia (<0.02 ml l(sup-1)) driven by the nearshore (<20 m isobath) decay of red tide. Coastal wind forcing influences DO concentrations in the nearshore through its influence on bay productivity and the development of red tides; through shoreward advection of the bottom pool of oxygen-depleted water as determined by the upwelling-downwelling cycle; and through its control of water column stratification and mixing. A seasonal decline in bottom DO concentrations of ~11.2 ml l(sup-1) occurs with a concurrent expansion of the bottom pool of oxygen depleted water in St Helena Bay. Upwelling of this water into the nearshore causes severe drops in DO concentration (<0.2 ml l(sup-1)), particularly during end-of-season upwelling, resulting in a significant narrowing of the habitable zone. Episodic anoxia through the entire water column is caused by localized degradation of red tides within the confines of the shallow nearshore environment. Oxygenation of the nearshore is achieved by ventilation of the water column particularly with the onset of winter mixing. No notable changes are evident in comparing recent measures of bottom DO concentrations in St Helena Bay to data collected in the late 1950s and early 1960s. en_US
dc.language.iso en en_US
dc.publisher Wiley en_US
dc.relation.ispartofseries Workflow;13087
dc.subject St Helena Bay en_US
dc.subject Southern Benguela upwelling system en_US
dc.subject Oxygen depletion en_US
dc.subject Dissolved oxygen(DO) en_US
dc.subject DO concentration en_US
dc.subject Episodic anoxia en_US
dc.title Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system en_US
dc.type Article en_US
dc.identifier.apacitation Pitcher, G., Probyn, T., Du Randt, A., Lucas, A., Bernard, S., Evers-King, H., ... Hutchings, L. (2014). Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system. http://hdl.handle.net/10204/7541 en_ZA
dc.identifier.chicagocitation Pitcher, GC, TA Probyn, A Du Randt, AJ Lucas, Stewart Bernard, H Evers-King, T Lamont, and L Hutchings "Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system." (2014) http://hdl.handle.net/10204/7541 en_ZA
dc.identifier.vancouvercitation Pitcher G, Probyn T, Du Randt A, Lucas A, Bernard S, Evers-King H, et al. Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system. 2014; http://hdl.handle.net/10204/7541. en_ZA
dc.identifier.ris TY - Article AU - Pitcher, GC AU - Probyn, TA AU - Du Randt, A AU - Lucas, AJ AU - Bernard, Stewart AU - Evers-King, H AU - Lamont, T AU - Hutchings, L AB - Acquisition of high resolution time series of water column and bottom dissolved oxygen (DO) concentrations inform the dynamics of oxygen depletion in St Helena Bay in the southern Benguela upwelling system at several scales of variability. The bay is characterized by seasonally recurrent hypoxia (<1.42 ml l(sup-1)) associated with a deep pool of oxygen-depleted water and episodic anoxia (<0.02 ml l(sup-1)) driven by the nearshore (<20 m isobath) decay of red tide. Coastal wind forcing influences DO concentrations in the nearshore through its influence on bay productivity and the development of red tides; through shoreward advection of the bottom pool of oxygen-depleted water as determined by the upwelling-downwelling cycle; and through its control of water column stratification and mixing. A seasonal decline in bottom DO concentrations of ~11.2 ml l(sup-1) occurs with a concurrent expansion of the bottom pool of oxygen depleted water in St Helena Bay. Upwelling of this water into the nearshore causes severe drops in DO concentration (<0.2 ml l(sup-1)), particularly during end-of-season upwelling, resulting in a significant narrowing of the habitable zone. Episodic anoxia through the entire water column is caused by localized degradation of red tides within the confines of the shallow nearshore environment. Oxygenation of the nearshore is achieved by ventilation of the water column particularly with the onset of winter mixing. No notable changes are evident in comparing recent measures of bottom DO concentrations in St Helena Bay to data collected in the late 1950s and early 1960s. DA - 2014-04 DB - ResearchSpace DP - CSIR KW - St Helena Bay KW - Southern Benguela upwelling system KW - Oxygen depletion KW - Dissolved oxygen(DO) KW - DO concentration KW - Episodic anoxia LK - https://researchspace.csir.co.za PY - 2014 SM - 2169-9275 T1 - Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system TI - Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system UR - http://hdl.handle.net/10204/7541 ER - en_ZA


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