Investigation of geographic variation in the thermal tolerance of zebra mussels, Dreissena polymorpha

Technical Report · Thu Jun 01 04:00:00 EDT 1995

OSTI ID:146958

Hernandez, M R; McMahon, R F ^[1]; Dietz, T H ^[2]

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1. Univ. of Texas, Arlington, TX (United States)
2. Louisiana State Univ., Baton Rouge, LA (United States)

Data previously collected from endemic northern European populations indicated a maximum, long-term upper thermal limit of 28{degrees}C for D. polymorpha, a temperature well below maximum, summer-daytime, surface water temperatures in the lower Mississippi River ({>=}30{degrees}C). Thus, it has been speculated that natural selection for thermal tolerance among zebra mussels in the warm waters may have led to development of genetically more thermally tolerant populations than presently occur in the cooler waters of the Great Lakes. In order to investigate this possibility, thermal tolerance times on continual exposure to a lethal temperature of 33{degrees}C were determined for samples of zebra mussels collected biweekly in the lower Mississippi River from 14 March through 18 October, 1994 and from the Niagara River on 24 May and 9 August 1994. Multiple factor ANOVA indicated that while there were differences in mean thermal tolerance times among acclimation groups and with time of collection, there was no difference in thermal tolerance between the Niagara and lower Mississippi River populations. Least Squares Analysis indicated that sample mean thermal tolerance times among lower Mississippi River mussels increased, suggestive of a seasonal pattern of thermal tolerance regulation which could not be eliminated by laboratory temperature acclimation. Such seasonal thermal tolerance acclimatization may make fouling populations of D. polymorpha more resistant to thermal mitigation during summer months. It may also partially account for the reduced thermal tolerance reported among northern European populations drawn from much cooler waters than those of the lower Great Lakes and lower Mississippi River. Lack of significant thermal tolerance differences between Niagara and lower Mississippi River zebra mussels suggests that there has been no selection for a thermally tolerant physiological race of D. polymorpha in the lower Mississippi River.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 146958
• Report Number(s): EPRI-TR--105116; CONF-9502124--; CNN: Grant DAAH04-94-G-0118
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
55 BIOLOGY AND MEDICINE
BASIC STUDIES
BENTHOS
BIOLOGICAL FOULING
CONTROL
DIAGRAMS
GEOGRAPHICAL VARIATIONS
MUSSELS
NUMERICAL DATA
TEMPERATURE DEPENDENCE