HR: 1330h
AN: NB33R-05    [Abstracts]
TI: Status of Lake Superior Benthic Macroinvertebrates, 1994-2003
AU: * Scharold, J
EM: scharold.jill@epa.gov
AF: US EPA Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 United States
AU: Lozano, S J
AF: NOAA Great Lakes Environmental Research Laboratory, 2205 Commonwealth Blvd., Ann Arbor, MN 48105 United States
AU: Corry, T D
AF: US EPA Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 United States
AB: Recently documented changes to benthic communities in the lower Great Lakes have created concerns about the status of benthic macroinvertebrates in Lake Superior. This lakewide study was conducted to ascertain their status in U.S. nearshore waters of Lake Superior. Benthic macroinvertebrates were collected from 27 sites representing the U.S. nearshore waters (20 to 110 m) of Lake Superior in 1994, 2000, and 2003. No significant differences in total benthic macroinvertebrate abundance, or abundances of oligochaetes, clams or chironomids were detected between years. Abundance of the amphipod Diporeia spp. was lower in 2000 than in 1994 and 2003. The oligochaete trophic index, a measure of relative abundance of species tolerant of varying degrees of organic enrichment, did not differ between years. Diporeia exhibited a bimodal depth distribution, with peaks in abundance at depths of 30 to 40 and 60 to 70 m. Oligochaetes were most abundant at 50 to 60 m depth, clams between 30 and 70 m, and chironomids at less than 30 m, with a secondary peak at 50 to 60 m. The spatial and temporal variability observed in Lake Superior benthic macroinvertebrate communities has implications for sampling design for environmental assessment. This abstract does not necessarily reflect USEPA policy.
DE: 4239 Limnology
DE: 4804 Benthic processes/benthos
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly