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| Titel |
Testing the impact of calcareous nannofossil size evolution on pelagic carbonate burial over the past 17 million years |
| VerfasserIn |
Baptiste Suchéras-Marx, Jorijntje Henderiks |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082742
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| Zusammenfassung |
| Calcareous nannofossils (i.e., coccoliths and incertae sedis such as Discoasters) are the
products of marine, unicellular calcifying algae. Calcifying phytoplankton play a
fundamental role in marine ecosystems and global biogeochemical cycles. Their size and
abundance determine the strength of the biological carbon and carbonate “pumps”,
which represent important feedbacks to the carbon cycle. Despite their small size
ranging from 2 to 20 micrometer, they contribute about half of the total pelagic
carbonate burial in today’s oceans. An overall macroevolutionary decrease in the size of
these carbonate producers is recorded over the Cenozoic, but the impact of this
turnover on pelagic carbonate burial rates has remained unquantified. Here, we
investigate the past 17 million years (Ma) to quantify the nannofossil flux (number of
nannofossils/m2/yr) and the corresponding nannofossil carbonate flux (g/m2/yr) in
40 samples from five DSDP/ODP sites from the North Atlantic, South Atlantic,
Eastern Indian, Western Indian and Western Pacific Oceans. Three different size
assemblages are observed. From 17 Ma to 10 Ma, the assemblages were dominated by
large coccolith species, mostly Coccolithus pelagicus and large reticulofenestrids.
From 10 Ma to 5 Ma, the abundance of large-sized coccoliths diminished while
medium-sized reticulofenestrids became the most abundant species. After 5 Ma,
small-sized reticulofenestrids ( |
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