Soluble and colloidal iron in the olgotrophic North Atlantic and North Pacific

被引:360
作者
Wu, JF
Boyle, E
Sunda, W
Wen, LS
机构
[1] MIT, Cambridge, MA 02139 USA
[2] NOAA, Beaufort Lab, Beaufort, NC 28516 USA
[3] CNR, Natl Ctr Ocean Res, Taipei, Taiwan
关键词
D O I
10.1126/science.1059251
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
In the oligotrophic North Atlantic and North Pacific, ultrafiltration studies show that concentrations of soluble iron and soluble iron-binding organic ligands are much lower than previously presumed "dissolved" concentrations, which were operationally defined as that passing through a 0.4-micrometer pore filter. Our studies indicate that substantial portions of the previously presumed "dissolved" iron (and probably also iron-binding ligands) are present in colloidal size range. The soluble iron and iron-binding organic ligands are depleted at the surface and enriched at depth, similar to distributions of major nutrients. By contrast, colloidal iron shows a maximum at the surface and a minimum in the upper nutricline. Our results suggest that "dissolved" iron may be less bioavailable to phytoplankton than previously thought and that iron removal through colloid aggregation and settling should be considered in models of the oceanic iron cycle.
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页码:847 / 849
页数:3
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