 |
| Titel |
The effects of biomanipulation on the biogeochemistry, carbon isotopic composition and pelagic food web relations of a shallow lake |
| VerfasserIn |
B. M. Bontes, R. Pel, B. W. Ibelings, H. T. S. Boschker, J. J. Middelburg, E. Donk |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 3, no. 1 ; Nr. 3, no. 1 (2006-03-02), S.69-83 |
| Datensatznummer |
250000732
|
| Publikation (Nr.) |
 copernicus.org/bg-3-69-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
In this study we investigated the effects of experimental biomanipulation on
community structure, ecosystem metabolism, carbon biogeochemistry and stable
isotope composition of a shallow eutrophic lake in the Netherlands. Three
different biomanipulation treatments were applied. In two parts of the lake,
isolated from the rest, fish was removed and one part was used as a
reference treatment in which no biomanipulation was applied. Stable isotopes
have proved useful to trace trophic interactions at higher food web levels
but until now methodological limitations have restricted species specific
isotope analysis in the plankton community. We applied a new approach based
on the combination of fluorescence activated cell sorting (FACS) and isotope
ratio mass spectrometry (IRMS) to trace carbon flow through the planktonic
food web. With this method we aimed at obtaining group specific δ13C signatures of phytoplankton and to trace possible shifts in δ13C resulting from fish removal.
Biomanipulation led to an increase in transparency and macrophyte biomass
and decrease in phytoplankton abundance, but zooplankton numbers did not
increase. Fish removal also resulted in high pH, high O2, low CO2
and more negative δ13CDIC values than expected, which is
attributed to chemical enhanced diffusion with large negative fractionation.
Despite high temporal variation we detected differences between the isotopic
signatures of the primary producers and between the different treatments.
The fractionation values of green algae (~21) and diatoms (~23)
were similar and independent of treatment, while fractionation factors
of filamentous cyanobacteria were variable between the treatments that
differed in CO2 availability. 13C-labeling of the phytoplankton
groups showed that biomanipulation led to increased growth rates of green
algae and diatoms at the expense of cyanobacteria. Finally, consumers seemed
generalists to the available food sources. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|