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| Titel |
Marine oxygen holes as a consequence of oceanic acidification |
| VerfasserIn |
M. Hofmann, H.-J. Schellnhuber |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250024697
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| Zusammenfassung |
| An increase of atmospheric CO2 levels will not only drive future global mean temperatures
towards values unprecedented during the whole Quaternary, but will also lead to an
acidification of sea water which could harm the marine biota. Here we assess possible
impacts of elevated atmospheric CO2 concentrations on the marine biological carbon pump
by utilizing a business-as-usual emission scenario of anthropogenic CO2. A corresponding
release of 4075 Petagrams of Carbon in total has been applied to simulate the current
millennium by employing an Earth System Model of Intermediate Complexity (EMIC). This
work is focused on studying the implications of reduced biogenic calcification caused
by an increasing degree of oceanic acidification on the marine biological carbon
pump.
The attenuation of biogenic calcification imposes a small negative feedback on rising
atmospheric pCO2 levels, tending to stabilize the Earth’s climate. Since mineral ballast,
notably particulate CaCO3, plays a dominant role in carrying organic matter through the
water column, a reduction of its export fluxes weakens the strength of the biological carbon
pump.
There is, however, a dramatic effect discovered in our model world with severe
consequences: since organic matter is oxidized in shallow waters when mineral-ballast
fluxes weaken, oxygen holes (hypoxic zones) start to expand considerably in the
oceans with potentially harmful impacts on a variety of marine ecosystems. Our
study indicates that unbridled ocean acidification would exacerbate the observed
hypoxia trends due to various environmental factors as reported in recent empirical
studies. |
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