Publication Date:
2010-10-29
Description:
Phosphorus is a biolimiting nutrient that has an important role in regulating the burial of organic matter and the redox state of the ocean-atmosphere system. The ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks can be used to track dissolved phosphate concentrations if the dissolved silica concentration of sea water is estimated. Here we present iron and phosphorus concentration ratios from distal hydrothermal sediments and iron formations through time to study the evolution of the marine phosphate reservoir. The data suggest that phosphate concentrations have been relatively constant over the Phanerozoic eon, the past 542 million years (Myr) of Earth's history. In contrast, phosphate concentrations seem to have been elevated in Precambrian oceans. Specifically, there is a peak in phosphorus-to-iron ratios in Neoproterozoic iron formations dating from approximately 750 to approximately 635 Myr ago, indicating unusually high dissolved phosphate concentrations in the aftermath of widespread, low-latitude 'snowball Earth' glaciations. An enhanced postglacial phosphate flux would have caused high rates of primary productivity and organic carbon burial and a transition to more oxidizing conditions in the ocean and atmosphere. The snowball Earth glaciations and Neoproterozoic oxidation are both suggested as triggers for the evolution and radiation of metazoans. We propose that these two factors are intimately linked; a glacially induced nutrient surplus could have led to an increase in atmospheric oxygen, paving the way for the rise of metazoan life.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Planavsky, Noah J -- Rouxel, Olivier J -- Bekker, Andrey -- Lalonde, Stefan V -- Konhauser, Kurt O -- Reinhard, Christopher T -- Lyons, Timothy W -- England -- Nature. 2010 Oct 28;467(7319):1088-90. doi: 10.1038/nature09485.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth Sciences, University of California, Riverside, California 92521, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20981096" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Aquatic Organisms/*metabolism
;
Atmosphere/chemistry
;
*Biological Evolution
;
Ferric Compounds/analysis/metabolism
;
Geologic Sediments/chemistry
;
History, Ancient
;
Ice Cover
;
Iron/analysis/metabolism
;
Marine Biology
;
Oceans and Seas
;
Oxidation-Reduction
;
Oxygen/analysis/metabolism
;
Phosphates/analysis/*metabolism
;
Phosphorus/analysis/metabolism
;
Seawater/chemistry
;
Silicon Dioxide/analysis/metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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