Publicação da Revista Nature desse mês de outubro, ótimo artigo.
The evolution of the marine phosphate reservoir
Noah J. Planavsky1,2, Olivier J. Rouxel2,3, Andrey Bekker4, Stefan V. Lalonde5, Kurt O. Konhauser5, Christopher T. Reinhard1 & Timothy W. Lyons1
- Department of Earth Sciences, University of California, Riverside, California 92521, USA
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institute, Woods Hole, Massachusetts 02543, USA
- Université Européene de Bretagne, European Institute for Marine Studies, Technopôle Brest-Iroise, Place Nicolas Copernic, 29280 Plouzané, France
- Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
Correspondence to: Timothy W. Lyons1 Email: timothy.lyons@ucr.edu
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Abstract
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 system1. 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 estimated2, 3, 4, 5. 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 ~750 to ~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 metazoans6, 7. 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.
- Department of Earth Sciences, University of California, Riverside, California 92521, USA
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institute, Woods Hole, Massachusetts 02543, USA
- Université Européene de Bretagne, European Institute for Marine Studies, Technopôle Brest-Iroise, Place Nicolas Copernic, 29280 Plouzané, France
- Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
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