气候变化领域集成服务门户(CCPortal): (Table 2) Seasonal flux data and percentages of major bulk components of total flux at the mesotrophic sediment trap site CB from 1988

CCPortal

DOI	https://doi.org/10.1594/PANGAEA.867251
	(Table 2) Seasonal flux data and percentages of major bulk components of total flux at the mesotrophic sediment trap site CB from 1988 - 2012
	Fischer; Gerhard; Romero; Oscar E; Merkel; Ute; Donner; Barbara; Iversen; Morten Hvitfeldt; Nowald; Nicolas; Ratmeyer; Volker; Ruhland; Götz; Klann; Marco; Wefer; Gerold
发布日期	2016-10-26
数据集类型	dataset
英文简介	A more than two-decadal sediment trap record from the Eastern Boundary Upwelling Ecosystem (EBUE) off Cape Blanc, Mauritania, is analysed with respect to deep ocean mass fluxes, flux components and their variability on seasonal to decadal timescales. The total mass flux revealed interannual fluctuations which were superimposed by fluctuations on decadal timescales. High winter fluxes of biogenic silica (BSi), used as a measure of marine production (mostly by diatoms) largely correspond to a positive North Atlantic Oscillation (NAO) index (December-March). However, this relationship is weak. The highest positive BSi anomaly was in winter 2004-2005 when the NAO was in a neutral state. More episodic BSi sedimentation events occurred in several summer seasons between 2001 and 2005, when the previous winter NAO was neutral or even negative. We suggest that distinct dust outbreaks and deposition in the surface ocean in winter and occasionally in summer/autumn enhanced particle sedimentation and carbon export on short timescales via the ballasting effect. Episodic perturbations of the marine carbon cycle by dust outbreaks (e.g. in 2005) might have weakened the relationships between fluxes and large-scale climatic oscillations. As phytoplankton biomass is high throughout the year, any dry (in winter) or wet (in summer) deposition of fine-grained dust particles is assumed to enhance the efficiency of the biological pump by incorporating dust into dense and fast settling organic-rich aggregates. A good correspondence between BSi and dust fluxes was observed for the dusty year 2005, following a period of rather dry conditions in the Sahara/Sahel region. Large changes of all bulk fluxes occurred during the strongest El Niño-Southern Oscillation (ENSO) in 1997-1999 where low fluxes were obtained for almost 1 year during the warm El Niño and high fluxes in the following cold La Niña phase. For decadal timescales, Bakun (1990) suggested an intensification of coastal upwelling due to increased winds (''Bakun upwelling intensification hypothesis''; Cropper et al., 2014) and global climate change. We did not observe an increase of any flux component off Cape Blanc during the past 2 and a half decades which might support this. Furthermore, fluxes of mineral dust did not show any positive or negative trends over time which might suggest enhanced desertification or ''Saharan greening'' during the last few decades.
空间范围	Median Latitude: 21.232309 * Median Longitude: -20.719252 * South-bound Latitude: 20.755000 * West-bound Longitude: -20.848333 * North-bound Latitude: 21.300000 * East-bound Longitude: -19.742000
时间范围	1988-03-22T00:00:00 - 2012-09-12T00:00:00
语种	英语
国家	国际
学科大类	气候变化
学科子类	气候变化
文献类型	数据集
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/216744
推荐引用方式 GB/T 7714	Fischer,Gerhard,Romero,et al. (Table 2) Seasonal flux data and percentages of major bulk components of total flux at the mesotrophic sediment trap site CB from 1988 - 2012.2016-10-26.https://doi.org/10.1594/PANGAEA.867251.