 |
| Titel |
Short-term changes in particulate fluxes measured by drifting sediment traps during end summer oligotrophic regime in the NW Mediterranean Sea |
| VerfasserIn |
J. C. Marty, M. Goutx, C. Guigue, N. Leblond, P. Raimbault |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 5 ; Nr. 6, no. 5 (2009-05-20), S.887-899 |
| Datensatznummer |
250003750
|
| Publikation (Nr.) |
 copernicus.org/bg-6-887-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| Short-term changes in the flux of particulate matter were determined in the
central north western Mediterranean Sea (near DYFAMED site) using drifting
sediment traps at 200 m depth in the course of the DYNAPROC 2 cruise (14
September–17 October 2004). In this period of marked water column
stratification, POC fluxes varied by an order of magnitude, in the range of
0.03–0.29 mgC m−2 h−1 over the month and showed very rapid and
high variations. Particulate carbon export represented less than 5% of
integrated primary production, suggesting that phytoplankton production was
essentially sustained by internal recycling of organic matter and retained
within the photic zone. While PON and POP fluxes paralleled one another, the
elemental ratios POC/PON and POC/POP, varied widely over short-term periods.
Values of these ratios generally higher than the conventional Redfield
ratio, together with the very low chlorophyll a flux recorded in the traps
(mean 0.017 μg m−2 h−1), and the high phaeopigment and acyl
lipid hydrolysis metabolite concentrations of the settling material,
indicated that the organic matter reaching 200 m depth was reworked (by
grazing, fecal pellets production, degradation) and that algal sinking,
dominated by nano- and picoplankton, made a small contribution to the
downward flux. Over time, the relative abundance of individual lipid classes
in organic matter (OM) changed from glycolipids-dominated to neutral (wax
esters, triacylglycerols) and phospholipids-dominated, suggesting ecosystem
maturation as well as rapid and continual exchanges between dissolved,
suspended and sinking pools. Our most striking result was documenting the
rapid change in fluxes of the various measured parameters. In the situation
encountered here, with dominant regenerated production, a decrease of fluxes
was noticed during windy periods (possibly through reduction of grazing).
But fluxes increased as soon as calm conditions settle. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|