Freshwater plankton response to acidification

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6002592

Havens, III, K E

An in situ bag experiment was performed at circum-neutral Lake O'Woods, West Virgnia, where lakewater inside large enclosures was gradually acidified to pH 6.5 or 4.5, in order to examine plankton community succession during acidification. At acidic Cheat Lake (pH ca. 4.5), West Virginia, in situ feeding experiments and bag experiments were performed to evaluate the importance of selective herbivory in controlling algal community structure in acid lakes. The Lake O'Woods plankton community changed dramatically with increasing acidity. Species richness declined, as sensitive forms were eliminated. The phytoplankton became dominated by Peridinium inconspicuum and the filamentous green alga Mougoetia viridis, while euglenophytes, chrysophytes and diatoms were eliminated. Bosmina longirostris and Chydorus sphaericus were the dominant crustaceans at low pH. Only a single rotifer, Lecane luna, tolerated the acidic conditions. All others were eliminated at pH below 6.0. Despite the rapid acidification regime, the nature of the plankton community changes, as well as community structure at pH 4.5, were as predicted in the literature from earlier comparative studies. During the Cheat Lake feeding experiments, P. inconspicuum was always the extreme dominant alga. However, it was never significantly grazed by the herbivorous zooplankton. The herbivores selectively consumed the other, more rare algae, particularly the unicellular greens. Despite the existence of selective herbivory, algal community structure did not change inside enclosures where herbivores were excluded in a 26 and an 18 day experiment. Cheat Lake herbivores seem to have little effect on algal community structure. This is probably also true in most precipitation-acidified lakes. However, herbivore biomass, and also energy flow to higher trophic levels, may be suppressed because most of the primary producer biomass is inedible.

• OSTI ID: 6002592
• Country of Publication: United States
• Language: English

Related Subjects

520200 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
560302* -- Chemicals Metabolism & Toxicology-- Microorganisms-- (-1987)
560303 -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID RAIN
ACIDIFICATION
AIR POLLUTION
AQUATIC ECOSYSTEMS
AQUATIC ORGANISMS
ATMOSPHERIC PRECIPITATIONS
BIOLOGICAL EFFECTS
COMPARATIVE EVALUATIONS
ECOSYSTEMS
LAKES
PHYTOPLANKTON
PLANKTON
POLLUTION
POPULATION DYNAMICS
RAIN
SPECIES DIVERSITY
SURFACE WATERS
ZOOPLANKTON