气候变化领域集成服务门户(CCPortal): Net community production, Thorium-234 activity and particle flux during the Southern Ocean iron fertilization experiment LOHAFEX

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DOI	https://doi.org/10.1594/PANGAEA.832525
	Net community production, Thorium-234 activity and particle flux during the Southern Ocean iron fertilization experiment LOHAFEX
	Martin; Patrick; Rutgers van der Loeff; Michiel M; Cassar; Nicolas; Vandromme; Pieter; d'Ovidio; Francesco; Stemmann; Lars; Rengarajan; R; Soares; Melena; González; Humberto E; Ebersbach; Friederike; Lampitt; Richard Stephen; Sanders; Richard J; Barnett; Bruce A; Smetacek; Victor; Naqvi; Syed Wajih Ahmad
发布日期	2013-05-15
数据集类型	dataset
英文简介	A closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO4), and the 300 km2 fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux into the deep ocean. Chlorophyll a and primary productivity doubled after fertilization, and photosynthetic quantum yield (FV/FM) increased from 0.33 to >0.40. Silicic acid (<2 µmol/L) limited diatoms, which contributed <10% of phytoplankton biomass. Copepods exerted high grazing pressure. This is the first study of particle flux out of an artificially fertilized bloom with very low diatom biomass. Net community production (NCP) inside the patch, estimated from O2:Ar ratios, averaged 21 mmol POC/m2/d, probably ±20%. 234Th profiles implied constant export of ~6.3 mmol POC/m2/d in the patch, similar to unfertilized waters. The difference between NCP and 234Th-derived export partly accumulated in the mixed layer and was partly remineralized between the mixed layer and 100 m. Neutrally buoyant sediment traps at 200 and 450 m inside and outside the patch caught mostly <1.1 mmol POC/m2/d, predominantly of fecal origin; flux did not increase upon fertilization. Our data thus indicate intense flux attenuation between 100 and 200 m, and probably between the mixed layer and 100 m. We attribute the lack of fertilization-induced export to silicon limitation of diatoms and reprocessing of sinking particles by detritus feeders. Our data are consistent with the view that nitrate-rich but silicate-deficient waters are not poised for enhanced particle export upon iron addition.
空间范围	Median Latitude: -47.972615 * Median Longitude: -15.137787 * South-bound Latitude: -49.037300 * West-bound Longitude: -16.097930 * North-bound Latitude: -44.509310 * East-bound Longitude: -12.881320
时间范围	2009-01-26T13:04:00 - 2009-03-06T12:31:00
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/233546
推荐引用方式 GB/T 7714	Martin,Patrick,Rutgers van der Loeff,et al. Net community production, Thorium-234 activity and particle flux during the Southern Ocean iron fertilization experiment LOHAFEX.2013-05-15.https://doi.org/10.1594/PANGAEA.832525.