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| Titel |
Evidence for greater oxygen decline rates in the coastal ocean than in the open ocean |
| VerfasserIn |
D. Gilbert, N. N. Rabalais, R. J. Díaz, J. Zhang |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 7 ; Nr. 7, no. 7 (2010-07-26), S.2283-2296 |
| Datensatznummer |
250004905
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| Publikation (Nr.) |
 copernicus.org/bg-7-2283-2010.pdf |
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| Zusammenfassung |
| In the global ocean, the number of reported hypoxic sites (oxygen <30%
saturation) is on the rise both near the coast and in the open ocean. But
unfortunately, most of the papers on hypoxia only present oxygen data from
one or two years, so that we often lack a long-term perspective on whether
oxygen levels at these locations are decreasing, steady or increasing.
Consequently, we cannot rule out the possibility that many of the newly
reported hypoxic areas were hypoxic in the past, and that the increasing
number of hypoxic areas partly reflects increased research and monitoring
efforts. Here we address this shortcoming by computing oxygen concentration
trends in the global ocean from published time series and from time series
that we calculated using a global oxygen database. Our calculations reveal
that median oxygen decline rates are more severe in a 30 km band near the
coast than in the open ocean (>100 km from the coast). Percentages of
oxygen time series with negative oxygen trends are also greater in the
coastal ocean than in the open ocean. Finally, a significant difference
between median published oxygen trends and median trends calculated from raw
oxygen data suggests the existence of a publication bias in favor of negative
trends in the open ocean. |
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