气候变化领域集成服务门户(CCPortal): On-Shelf Nutrient Trapping Enhances the Fertility of the Southern Benguela Upwelling System

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DOI	10.1029/2019JC015948
	On-Shelf Nutrient Trapping Enhances the Fertility of the Southern Benguela Upwelling System
	Flynn R.F.; Granger J.; Veitch J.A.; Siedlecki S.; Burger J.M.; Pillay K.; Fawcett S.E.
发表日期	2020
ISSN	21699275
卷号	125 期号:6
英文摘要	The southern Benguela upwelling system (SBUS) supports high rates of primary productivity that sustain important commercial fisheries. The exceptional fertility of this system is reportedly fueled not only by upwelled nutrients but also by nutrients regenerated on the broad and shallow continental shelf. We measured nutrient concentrations and the nitrogen (N) and oxygen (O) isotope ratios (δ15N and δ18O) of nitrate along four zonal lines in the SBUS in late summer and early winter to evaluate the extent to which regenerated nutrients augment the upwelled nutrient reservoir originating offshore. During summer upwelling, a decrease in on-shelf nitrate δ18O revealed that 0–48% of the subsurface nutrients derived from in situ remineralization. The nitrate regenerated on-shelf in the more quiescent winter (0–63% of total nitrate) extended further offshore along the mid-shelf. A shoreward increase in subsurface nitrate δ15N and a greater N deficit in on-shelf bottom waters further indicated N loss to benthic (and at times, watercolumn) denitrification coincident with the on-shelf remineralization. Our data show that remineralized nutrients get trapped on the SBUS shelf in summer through early winter, enhancing the nutrient pool that can be upwelled to support surface production. We hypothesize that this process is aided by a number of equatorward-flowing hydrographic fronts that impede the lateral exchange of surface waters. The extent to which nutrients remain trapped on the shelf has implications for the occurrence of hypoxic events in the SBUS. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	hydrographic fronts; nitrate isotope ratios; nutrient regeneration; nutrient trapping; upwelling
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186842
作者单位	Department of Oceanography, University of Cape Town, Cape Town, South Africa; Marine Sciences Department, University of Connecticut, Mansfield, CT, United States; South African Environmental Observation Network (SAEON), Cape Town, South Africa; Nansen-Tutu Centre, Marine Research Institute, Department of Oceanography, University of Cape Town, Cape Town, South Africa; Branch: Oceans and Coasts, Department of Environmental Affairs (DEA), Cape Town, South Africa
推荐引用方式 GB/T 7714	Flynn R.F.,Granger J.,Veitch J.A.,et al. On-Shelf Nutrient Trapping Enhances the Fertility of the Southern Benguela Upwelling System[J],2020,125(6).
APA	Flynn R.F..,Granger J..,Veitch J.A..,Siedlecki S..,Burger J.M..,...&Fawcett S.E..(2020).On-Shelf Nutrient Trapping Enhances the Fertility of the Southern Benguela Upwelling System.Journal of Geophysical Research: Oceans,125(6).
MLA	Flynn R.F.,et al."On-Shelf Nutrient Trapping Enhances the Fertility of the Southern Benguela Upwelling System".Journal of Geophysical Research: Oceans 125.6(2020).