 |
|
|
 |
|
 |
| |
Welcome to ProQuest-CSA, your Guide to Discovery. ProQuest-CSA helps researchers worldwide find and manage relevant information in their field. If you're a member of an academic institution you may have access to CSA Illumina. Please contact your library to find out. |
|
 |
|
 |
|
Food Web Structure in the Shallow Eutrophic Lake Vortsjaerv
(Estonia)
Noges, T | Noges, P | Haberman, J | Kisand, V | Kangur, K | Kangur, A | Jarvalt, A
Limnologica [Limnologica]. Vol. 28, no. 1, pp. 115-128. Mar 1998.
Data on the biomass and productivity of phytoplankton, bacteria,
metazooplankton, macrozoobenthos and fishes in eutrophic Lake
Vortsjaerv (270 km super(2), mean depth 2.8 m) were used to
construct the carbon balance of the lake. The average annual
biomass (g C m super(-2)) and production (g C m super(-2) y
super(-1)) of different links of the food web were the following:
phytoplankton - 3 and 418 (PPtot as particulate + exudate
production), bacteria 0.1 and 90, herbivorous metazooplankton -
0.2 and 5, predatory metazooplankton - 0.043 and 0.52,
macrozoobenthos 0.72 and 1.32, plankti- and benthivorous fishes
1.47 and 0.76, piscivorous fishes 0.18 and 0.1, respectively. The
efficiency of the consumption of primary production by secondary
producers (metazooplankton, macrozoobenthos) was extremely low,
the annual mean ratio of the production of herbivorous zooplankton
(Pfzp) and particulate primary production (PPpart) was only 2.1%,
increasing to 2.6% if macrozoobenthos production (Pbent) was
included. As the bacterial production constituted 21.5% of PPtot,
the consumption of phytoplankton biomass proceeds most likely
through the microbial loop (protists and bacteria). Among-animal
interactions had a much greater efficiency, the yearly average
ratio of predatory and filtrative zooplankton (Ppzp/Pfzp) being
permanently higher than 10% and the ratio of the production of
nonpredatory fishes (Pnpfish) to Pfzp + Ppzp + Pbent being 12%:
The production of piscivorous fishes constituted 13% of Pnpfish.
Fish production (plankti-, benthi- and piscivores) constituted
0.34% of PPpart and 0.21% of PPtot. Top-down effects in L.
Vortsjaerv cascade to the link of filter-feeders (herbivorous
metazooplankton, macrozoobenthos) the amount and size-spectra of
which are effectively controlled by predation. Small-sized
filter-feeding zooplankton looses control over filamentous algae
and is forced from both sides (selective grazing, food quality) to
the niche of detritophagy and bacterivory.
 Descriptors: Article Subject Terms Bacteria | Biomass | Carbon | Eutrophic Lakes | Food
Chains | Food webs | Lakes | Phytoplankton | Predation | Productivity | Shallow Water | Zooplankton
|
|
|
|
