Abstract
Benthic community responses to lake eutrophication are poorly understood relative to pelagic responses. We
compared phytoplankton and periphyton productivity along a eutrophication gradient in Greenland, U.S., and Danish
lakes. Phytoplankton productivity increased along the phosphorus gradient (total phosphorus [TP] 5 2–430 mg
m23), but whole-lake benthic algal productivity decreased, substantially depressing increases in primary productivity
at the whole-lake scale. In shallow, oligotrophic Greenland lakes, periphyton was responsible for 80–98% of primary
production, whereas in Danish lakes with TP . 100 mg m23, phytoplankton were responsible for nearly 100% of
primary production. Benthic contributions ranged from 5 to 80% depending on morphometry and littoral habitat
composition in lakes with intermediate phosphorus concentrations. Thus, eutrophication was characterized by a
switch from benthic to pelagic dominance of primary productivity. Carbon stable isotope analysis showed that the
redistribution of primary production entailed a similar shift from periphyton to phytoplankton in the diets of zoobenthos.
Benthic and pelagic habitats were energetically linked through food web interactions, but eutrophication eroded
the benthic primary production pathway.
compared phytoplankton and periphyton productivity along a eutrophication gradient in Greenland, U.S., and Danish
lakes. Phytoplankton productivity increased along the phosphorus gradient (total phosphorus [TP] 5 2–430 mg
m23), but whole-lake benthic algal productivity decreased, substantially depressing increases in primary productivity
at the whole-lake scale. In shallow, oligotrophic Greenland lakes, periphyton was responsible for 80–98% of primary
production, whereas in Danish lakes with TP . 100 mg m23, phytoplankton were responsible for nearly 100% of
primary production. Benthic contributions ranged from 5 to 80% depending on morphometry and littoral habitat
composition in lakes with intermediate phosphorus concentrations. Thus, eutrophication was characterized by a
switch from benthic to pelagic dominance of primary productivity. Carbon stable isotope analysis showed that the
redistribution of primary production entailed a similar shift from periphyton to phytoplankton in the diets of zoobenthos.
Benthic and pelagic habitats were energetically linked through food web interactions, but eutrophication eroded
the benthic primary production pathway.
| Original language | English |
|---|---|
| Journal | Limnology and Oceanography |
| Issue number | 48(4) |
| Pages (from-to) | 1408-1418 |
| ISSN | 0024-3590 |
| Publication status | Published - 2003 |