气候变化领域集成服务门户(CCPortal): Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean

CCPortal

DOI	10.1029/2019GB006397
	Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean
	Janssen D.J.; Rickli J.; Quay P.D.; White A.E.; Nasemann P.; Jaccard S.L.
发表日期	2020
ISSN	0886-6236
EISSN	1944-9224
卷号	34 期号:1
英文摘要	While chromium stable isotopes (δ53Cr) have received significant attention for their utility as a tracer of oxygen availability in the distant geological past, a mechanistic understanding of modern oceanic controls on Cr and δ53Cr is still lacking. Here we present total dissolved δ53Cr, concentrations of Cr (III) and total dissolved Cr, and net community productivity (NCP) from the North Pacific. Chromium concentrations show surface depletions in waters with elevated NCP, but not in lower productivity waters. Observed Cr deficits correspond well with calculated Cr export derived from NCP and Cr:C ratios of natural phytoplankton and marine particulates. Chromium (III) concentrations are stable over the diel cycle yet correlate with NCP, with maxima found in highly productive surface waters but not in lower productivity waters, indicating biological control on Cr (III). The relationship between Cr (III) and δ53Cr suggests that δ53Cr distributions may be controlled by the removal of isotopically light Cr (III) at an isotopic enrichment factor (∆53Cr) of −1.08‰ ± 0.25 relative to total dissolved δ53Cr, in agreement with the global δ53Cr-Cr fractionation factor (−0.82‰ ± 0.05). No perturbation to δ53Cr, Cr, or Cr (III) is observed in oxygen-depleted waters (~10 μmol/kg), suggesting no strong control by O2 availability, in agreement with other recent studies. Therefore, we propose that biological productivity is the primary control on Cr and δ53Cr in the modern ocean. Consequently, δ53Cr records in marine sediments may not faithfully record oxygen availability in the Late Quaternary. Instead, our data demonstrate that δ53Cr records may be a useful tracer for biological productivity. ©2020. The Authors.
英文关键词	biological productivity; chromium; chromium redox; GEOTRACES; paleoproxy; stable isotopes
语种	英语
scopus关键词	biological control; chromium; isotopic composition; isotopic fractionation; phytoplankton; stable isotope; tracer; Pacific Ocean; Pacific Ocean (North)
来源期刊	Global Biogeochemical Cycles
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/129676
作者单位	Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland; Institute of Geochemistry and Petrology, ETH Zürich, Zürich, Switzerland; School of Oceanography, University of Washington, Seattle, WA, United States; School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, Honolulu, HI, United States
推荐引用方式 GB/T 7714	Janssen D.J.,Rickli J.,Quay P.D.,et al. Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean[J],2020,34(1).
APA	Janssen D.J.,Rickli J.,Quay P.D.,White A.E.,Nasemann P.,&Jaccard S.L..(2020).Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean.Global Biogeochemical Cycles,34(1).
MLA	Janssen D.J.,et al."Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean".Global Biogeochemical Cycles 34.1(2020).