干旱区生态环境知识资源中心(Arid): Seasonal flux patterns and carbon transport from low-oxygen eddies at the Cape Verde Ocean Observatory: lessons learned from a time series sediment trap study (2009-2016)

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DOI	10.5194/bg-18-6479-2021
	Seasonal flux patterns and carbon transport from low-oxygen eddies at the Cape Verde Ocean Observatory: lessons learned from a time series sediment trap study (2009-2016)
	Fischer, Gerhard; Romero, Oscar E.; Karstensen, Johannes; Baumann, Karl-Heinz; Moradi, Nasrollah; Iversen, Morten; Ruhland, Goetz; Klann, Marco; Koertzinger, Arne
通讯作者	Fischer, G (corresponding author), Univ Bremen, Geosci Dept, Klagenfurter Str 2-4, D-28359 Bremen, Germany. ; Fischer, G (corresponding author), Univ Bremen, MARUM Ctr Marine Environm Sci, Leobener Str 8, D-28359 Bremen, Germany.
来源期刊	BIOGEOSCIENCES
ISSN	1726-4170
EISSN	1726-4189
出版年	2021
卷号	18 期号:24 页码:6479-6500
英文摘要	Mesoscale eddies are abundant in the eastern tropical North Atlantic and act as oases for phytoplankton growth due to local enrichment of nutrients in otherwise oligotrophic waters. It is not clear whether these eddies can efficiently transfer organic carbon and other flux components to depth and if they are important for the marine carbon budget. Due to their transient and regionally restricted nature, measurements of eddies' contribution to bathypelagic particle flux are difficult to obtain. Rare observations of export flux associated with low-oxygen eddies have suggested efficient export from the surface to the deep ocean, indicating that organic carbon flux attenuation might be low. Here we report on particle flux dynamics north of the Cabo Verde islands at the oligotrophic Cape Verde Ocean Observatory (CVOO; approx. 17 degrees 35' N, 24 degrees 15' W). The CVOO site is located in the preferred pathways of highly productive eddies that ultimately originate from the Mauritanian upwelling region. Between 2009 and 2016, we collected biogenic and lithogenic particle fluxes with sediment traps moored at ca. 1 and 3 km water depths at the CVOO site. From concurrent hydrography and oxygen observations, we confirm earlier findings that highly productive eddies are characterized by colder and less saline waters and a low-oxygen signal as well. Overall, we observed quite consistent seasonal flux patterns during the passage of highly productive eddies in the winters of 2010, 2012 and 2016. We found flux increases at 3 km depth during October-November when the eddies approached CVOO and distinct flux peaks during February-March, clearly exceeding low oligotrophic background fluxes during winter 2011 and showing an enhanced particle flux seasonality. During spring, we observed a stepwise flux decrease leading to summer flux minima The flux pattern of biogenic silicate (BSi) showed a stronger seasonality compared to organic carbon. Additionally, the deep fluxes of total mass showed an unusually higher seasonality compared to the 1 km traps. We assume that BSi and organic carbon/lithogenic material had different sources within the eddies. BSi-rich particles may originate at the eddy boundaries where large diatom aggregates are formed due to strong shear and turbulence, resulting in gravitational settling and, additionally, in an active local downward transport. Organic carbon associated with lithogenic material is assumed to originate from the interior of eddies or from mixed sources, both constituting smaller, dust-ballasted particles. Our findings suggest that the regularly passing highly productive eddies at CVOO repeatedly release characteristic flux signals to the bathypelagic zone during winter-spring seasons that are far above the oligotrophic background fluxes and sequester higher organic carbon than during oligotrophic settings. However, the reasons for a lower carbon flux attenuation below eddies remain elusive.
类型	Article
语种	英语
开放获取类型	gold, Green Accepted
收录类别	SCI-E
WOS记录号	WOS:000731519700001
WOS关键词	PARTICULATE ORGANIC-CARBON ; DOWNWARD PARTICLE FLUXES ; MESOSCALE EDDIES ; MARINE SNOW ; DEEP-OCEAN ; SINKING VELOCITY ; MINIMUM ZONES ; SARGASSO SEA ; DEAD-ZONE ; ATLANTIC
WOS类目	Ecology ; Geosciences, Multidisciplinary
WOS研究方向	Environmental Sciences & Ecology ; Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/374142
作者单位	[Fischer, Gerhard; Baumann, Karl-Heinz] Univ Bremen, Geosci Dept, Klagenfurter Str 2-4, D-28359 Bremen, Germany; [Fischer, Gerhard; Romero, Oscar E.; Moradi, Nasrollah; Iversen, Morten; Ruhland, Goetz; Klann, Marco] Univ Bremen, MARUM Ctr Marine Environm Sci, Leobener Str 8, D-28359 Bremen, Germany; [Romero, Oscar E.; Iversen, Morten] Helmholtz Ctr Polar & Marine Res, Alfred Wegener Inst, D-27570 Bremerhaven, Germany; [Karstensen, Johannes; Koertzinger, Arne] GEOMAR Helmholtz Ctr Ocean Res Kiel, Dusternbrooker Weg 20, D-24105 Kiel, Germany
推荐引用方式 GB/T 7714	Fischer, Gerhard,Romero, Oscar E.,Karstensen, Johannes,et al. Seasonal flux patterns and carbon transport from low-oxygen eddies at the Cape Verde Ocean Observatory: lessons learned from a time series sediment trap study (2009-2016)[J],2021,18(24):6479-6500.
APA	Fischer, Gerhard.,Romero, Oscar E..,Karstensen, Johannes.,Baumann, Karl-Heinz.,Moradi, Nasrollah.,...&Koertzinger, Arne.(2021).Seasonal flux patterns and carbon transport from low-oxygen eddies at the Cape Verde Ocean Observatory: lessons learned from a time series sediment trap study (2009-2016).BIOGEOSCIENCES,18(24),6479-6500.
MLA	Fischer, Gerhard,et al."Seasonal flux patterns and carbon transport from low-oxygen eddies at the Cape Verde Ocean Observatory: lessons learned from a time series sediment trap study (2009-2016)".BIOGEOSCIENCES 18.24(2021):6479-6500.