Energy flow in an arctic aquatic ecosystem Page: 4 of 12
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BACKGROUND
In spite of an extremely harsh environment, the lakes
and ponds of the Alaskan arctic coastal plain support abundant
aquatic fauna and associated avifauna. In situ primary produc-
tion is sufficient, however, for only a small fraction of the
energy demands of the large invertebrate populations of insect
larvae and crustaceans (Butler, et al.,1980). Allochthonous
carbon sources were assumed, therefore, to fill the shortfall and
attempts have been made to quantify the inputs of terrestrial
carbon to the freshwater habitat carried by runoff or the intro-
duction of vegetative litter derived from emergent macrophytes
(Alexander, et al.,1980). An alternate potential source of car-
bon is the peat which underlies the vegetative mat, but the
highly degraded nature and ubiquitous presence of this substance
suggested that this material was resistant to microbial usage
(Hobbie, 1980). The overall energy source allocations have re-
mained an uncertain aspect of arctic freshwater foodwebs, es-
pecially with regard to the full annual cycle during which energy
dependencies may shift completely in response to the changes in
ice cover and daylight.
The principal investigator became involved in foodweb
studies in the Arctic first with the IBP Tundra Biome and then
with the NOAA/OCSEAP studies of the nearshore marine ecosystem.
In the coastal waters, many of the same species present in tundra
lakes--oldsquaws, loons, phalaropes, ciscoes, whitefishes and
arctic char -- were also using the food resources of the marine
environment. Some species such as the oldsquaw (Clangula
hyemalis) may nest on the tundra and feed on freshwater prey or-
ganisms or may remain on the marine lagoons (males and non-
breeders) for all or part of the summer. The anadromous fishes
migrate into the lagoons to feed in the summer and return into
the freshwater drainages to overwinter and spawn. In the process
of sorting out the energy supplies and trophic interdependencies
of the larger apical organisms while in the lagoons, we sought to
establish the magnitudes of energy (carbon) inputs arising from
primary production, fluvial inputs of "new" terrestrial vegeta-
tion and peat.
Assessing the role of peat in the trophic energetics of the
system presented a problem in that feeding studies on the major
invertebrates would be tedious and ran the risk of being incon-
clusive because of the temporal constraints. By comparing the
stable carbon isotope ratios of the nearshore fauna and their
carbon sources, it was possible to separate terrestrial from4
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Schell, D.M. Energy flow in an arctic aquatic ecosystem, report, January 1, 1983; United States. (https://digital.library.unt.edu/ark:/67531/metadc1186062/m1/4/?rotate=0: accessed July 18, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.