 |
| Titel |
Macrobenthic assemblage structure and organismal stoichiometry control faunal processing of particulate organic carbon and nitrogen in oxygen minimum zone sediments |
| VerfasserIn |
W. R. Hunter, L. A. Levin, H. Kitazato, U. Witte |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 3 ; Nr. 9, no. 3 (2012-03-13), S.993-1006 |
| Datensatznummer |
250006839
|
| Publikation (Nr.) |
 copernicus.org/bg-9-993-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Arabian Sea oxygen minimum zone (OMZ) impinges on the western Indian
continental margin between 150 and 1500 m, causing gradients in oxygen
availability and sediment geochemistry at the sea floor. Oxygen availability
and sediment geochemistry are important factors structuring macrofaunal
assemblages in marine sediments. However, relationships between macrofaunal
assemblage structure and sea-floor carbon and nitrogen cycling are poorly
understood. We conducted in situ 13C:15N tracer experiments in the OMZ
core (540 m [O2] = 0.35 μmol l–1) and lower OMZ boundary (800–1100 m,
[O2] = 2.2–15.0 μmol l–1) to investigate how
macrofaunal assemblage structure, affected by different oxygen levels, and
C:N coupling influence the fate of particulate organic matter. No macrofauna
were present in the OMZ core. Within the OMZ boundary, relatively high
abundance and biomass resulted in the highest macrofaunal assimilation of
particulate organic carbon (POC) and nitrogen (PON) at the lower oxygen 800 m stations
([O2] = 2.2–2.36 μmol l–1). At these stations
the numerically dominant cirratulid polychaetes exhibited greatest POC and
PON uptake. By contrast, at the higher oxygen 1100 m station ([O2] = 15.0 μmol l–1) macrofaunal C and N assimilation was lower, with POC assimilation dominated by one large solitary ascidian. Macrofaunal POC
and PON assimilation were influenced by changes in oxygen availability, and
significantly correlated to differences in macrofaunal assemblage structure
between stations. However, macrofaunal feeding responses were ultimately
characterised by preferential organic nitrogen assimilation, relative to
their internal C:N budgets. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|