Iron input and the export and burial of biogenic silica (opal produced from diatoms)

http://www.sciencedaily.com/releases/2012/03/120313140434.htm

Input of Iron Linked to Biological Productivity in Ancient Pacific
Ocean

"By closely examining the sedimentary record, Murray and his
colleagues have established a clear relationship between plant
plankton (diatoms) and the input of iron, exactly as Martin
predicted."

...

"By examining the paleo-oceanographic record of iron input and the
deposition of diatoms, Murray and his colleagues found that the
ancient system is highly consistent with what occurs in the oceans
today."

...

"The new publication provides an important sedimentary record from the
high-nutrient, low-chlorophyll region of the equatorial Pacific Ocean,
and shows strong links between iron input and the export and burial of
biogenic silica (opal produced from diatoms) over the past million
years."

The full paper is available at -

http://www.nature.com/ngeo/journal/v5/n4/full/ngeo1422.html

NATURE GEOSCIENCE | LETTER
Links between iron input and opal deposition in the Pleistocene equatorial Pacific Ocean

Richard W. Murray, Margaret Leinen & Christopher W. Knowlton
Nature Geoscience 5, 270–274 (2012) doi:10.1038/ngeo1422
Published online 11 March 2012

Increases in overall marine primary productivity and export production in high-nutrient, low-chlorophyll regions of the ocean have, particularly during dry and dusty glacial periods, been hypothesized to be linked to the enhanced delivery of iron1. In the modern ocean, iron availability limits production in high-nutrient, low-chlorophyll regions, and may be important in lower-nutrient settings as well2. Here, we assess the relationship between productivity and iron in sedimentary records from the high-nutrient, low-chlorophyll region of the equatorial Pacific Ocean over the past million years. We find strong links between iron input, the export and burial of biogenic silica (opal) and total export production. Our data demonstrate that iron accumulation was more closely tied to the accumulation of opal than any other biogenic component, with high iron input associated with substantially increased opal sedimentation. The strong links between iron and opal accumulation over the past one million years are in agreement with the modern biogeochemical behaviour of iron and silica, and the response of the diatom community to their mutual availablity3, 4. Our data support earlier suggestions1 of a biological response to iron delivery over geologic timescales.


This paper clearly mentions Diatoms as the phytoplankton that
sequester more carbon than other phytoplankton.