Plankton have traditionally been viewed as the basis for limnetic food webs, with zooplankton acting as a gateway for energy passing between phytoplanktonic primary producers and fish. Often, benthic production has been considered to be important primarily in shallow systems or as a subsidy to planktonic food web pathways. Stable isotope food web analyses of two arctic lakes (NE14 and I minus) in the Toolik Lake region of Alaska indicate that benthos are the primary source of carbon for adults of all species of benthic and pelagic fish present. We found no effect of turbidity, which may suppress benthic algae by shading, on food web structure. Even though Secchi transparency varied from 10.2 m in NE14 to 0.55-2.6 m in I minus, food webs in both lakes were based upon benthos, had four trophic levels, and culminated with omnivorous lake trout. We suggest that the importance of benthos in the food webs of these lakes is due to their extreme oligotrophy, resulting in planktonic resources that are insufficient for the support of planktivorous consumers.
|Original language||English (US)|
|Number of pages||9|
|State||Published - Oct 2003|
Bibliographical noteFunding Information:
We would like to thank Michael C. Miller (University of Cincinnati, OH) and Anne Giblin (Marine Biological Laboratory, Woods Hole, MA) for providing unpublished limnological data on the lakes, James Lee for aging the lake trout and analyzing age, length, and weight data, and Valerie Brady and Anne Cotter for assistance with stable isotope analyses. We wish to thank Jack Kelly, Chris Luecke, Anett Trebitz, and an anonymous reviewer for critical comments on the manuscript. This work was supported by NSF grants to John Hobbie, with a subcontract to M.E.M. The information in this document has been funded in part by the U. S. Environmental Protection Agency. It has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.
- Food webs
- Stable isotopes
- Trophic structure