 |
| Titel |
Autotrophic and heterotrophic metabolism of microbial planktonic communities in an oligotrophic coastal marine ecosystem: seasonal dynamics and episodic events |
| VerfasserIn |
O. Bonilla-Findji, J.-P. Gattuso, M.-D. Pizay, M. G. Weinbauer |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 11 ; Nr. 7, no. 11 (2010-11-08), S.3491-3503 |
| Datensatznummer |
250005053
|
| Publikation (Nr.) |
 copernicus.org/bg-7-3491-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| A 18 month study was performed in the Bay of Villefranche to assess the
episodic and seasonal variation of autotrophic and heterotrophic ecosystem
processes. A typical spring bloom was encountered, where maximum of gross
primary production (GPP) was followed by maxima of bacterial respiration
(BR) and production (BP). The trophic balance (heterotrophy vs. autotrophy)
of the system did not exhibit any seasonal trend although a strong
intra-annual variability was observed. On average, the community tended to
be net heterotrophic with a GPP threshold for a balanced metabolism of 1.1 μmol O2 l−1 d−1.
Extended forest fires in summer 2003
and a local episodic upwelling in July 2003 likely supplied orthophosphate
and nitrate into the system. These events were associated with an enhanced
bacterioplankton production (up to 2.4-fold), respiration (up to 4.5-fold)
and growth efficiency (up to 2.9-fold) but had no effect on GPP. A Sahara
dust wet deposition event in February 2004 stimulated bacterial abundance,
production and growth efficiency but not GPP. Our study suggests that
short-term disturbances such as wind-driven upwelling, forest fires and
Sahara dust depositions can have a significant but previously not
sufficiently considered influence on phytoplankton- and
bacterioplankton-mediated ecosystem functions and can modify or even mask
the seasonal dynamics. The study also indicates that atmospheric deposition
of nutrients and particles not only impacts phytoplankton but also
bacterioplankton and could, at times, also shift systems stronger towards
net heterotrophy. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|