BELL, ROBERT A. Department of Biology, University of Wisconsin - Stevens Point, Stevens Point, WI, 54481. - Phytoplankton community composition in the Tri-Lakes area of central Wisconsin, USA.
Tri-Lakes (Upper and Lower Camelot, Sherwood, Arrowhead) in Adams
County, Wisconsin are man-made impoundments draining substantial
agricultural lands and surrounded by considerable shoreline
residential development. The planktonic algal community, as sampled
from June - November 2000, was sparse to moderately dense, fairly
diverse (69 genera from 6 divisions basin-wide), and unremarkable in
taxonomic composition. All sites sampled displayed the general algal
successional trends expected from northern-temperate, mildly eutrophic
waters. These included: sparse but taxonomically diverse communities
in the spring; a late spring pulse of diatoms; a late summer pulse of
green algae; and a steadily increasing component of Cyanobacteria
leading to their community dominance by the end of the growing season.
Upper Lake Camelot (55 genera) best represented this pattern. Lower
Lake Camelot (53 genera) had a large green algal pulse but only a
small diatom pulse. Lake Sherwood was the most taxonomically diverse
body (63 genera) and had the most extreme pulses of diatoms and
greens. Lake Arrowhead had the lowest taxonomic diversity (39 genera),
was the most dominated by Cyanobacteria, and had only minor pulses of
diatoms and greens. The algal communities indicate a mesotrophic to
slightly eutrophic lake status. Continued agricultural and
residential inputs of fertilizers and pesticides will likely
exacerbate the cyanobacterial dominance leading to further reductions
in aquatic health and aesthetic values. Previous chemical treatment
and macrophyte removal have achieved limited success, and might have
altered algal community dynamics. Remediation approaches that might
improve water quality include: reducing upstream inputs via sediment
traps or lagoons; reducing in-lake nutrients via sediment removal;
reducing residential inputs via improved septic/sanitation systems;
and shoreline vegetation filter strips.
Key words: algal ecology, aquatic ecology, eutrophication, phytoplankton