DOI: 10.1002/gbc.20077
Scopus记录号: 2-s2.0-84883199569
论文题名: Iron fertilization enhanced net community production but not downward particle flux during the Southern Ocean iron fertilization experiment LOHAFEX
作者: Martin P ; , Van Der Loeff M ; R ; , Cassar N ; , Vandromme P ; , D'Ovidio F ; , Stemmann L ; , Rengarajan R ; , Soares M ; , González H ; E ; , Ebersbach F ; , Lampitt R ; S ; , Sanders R ; , Barnett B ; A ; , Smetacek V ; , Naqvi S ; W ; A
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2013
卷: 27, 期: 3 起始页码: 871
结束页码: 881
语种: 英语
英文关键词: 234-thoriumsediment traps
; iron fertilization
; net community production
; POC flux
Scopus关键词: 234-thoriumsediment traps
; Downward particle fluxes
; Iron fertilization
; Net community productions
; Phytoplankton biomass
; POC flux
; Primary productivity
; Sinking particles
; Photosynthesis
; Phytoplankton
; Silicates
; Silicon
; Iron
; biogeochemistry
; biomass
; chlorophyll a
; crustacean
; deep sea
; detritus
; diatom
; flagellate
; grazing pressure
; iron
; net ecosystem production
; particle motion
; particulate organic carbon
; photosynthesis
; primary production
; remineralization
; silicate
; Atlantic Ocean
; Southern Ocean
; Bacillariophyta
; Copepoda
; Mastigophora (flagellates)
英文摘要: 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-1) 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 m-2 d-1, probably ±20%. 234Th profiles implied constant export of ~6.3 mmol POC m-2 d-1 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 m-2 d-1, 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. Key Points Primary productivity and net community production increased upon fertilizationDue to silicon limitation, a bloom of small flagellates, not diatoms, developedParticle flux did not increase and was similar to fluxes in unfertilized waters ©2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/77580
Appears in Collections: 气候变化事实与影响
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作者单位: National Oceanography Centre, Southampton, United Kingdom; Earth Observatory of Singapore, 50 Nanyang Ave., Singapore, Singapore; Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany; Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University North Carolina, Durham, United States; LOV, Observatoire Océanologique, UPMC University of Paris 6, Villefranche/mer, France; GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany; LOCEAN-IPSL, CNRS/IRD/UPMC/MNHN, Paris, France; Physical Research Laboratory, Ahmedabad, India; National Institute of Oceanography, Dona Paula, India; Instituto de Ciencias Marinas y Limnolõgicas, Universidad Austral de Chile, Valdivia, Chile
Recommended Citation:
Martin P,, Van Der Loeff M,R,et al. Iron fertilization enhanced net community production but not downward particle flux during the Southern Ocean iron fertilization experiment LOHAFEX[J]. Global Biogeochemical Cycles,2013-01-01,27(3)