Honors Theses and Capstones

Date of Award

Spring 2014

Project Type

Senior Honors Thesis

College or School

COLSA

Department

Biological Sciences

Program or Major

Biology

Degree Name

Bachelor of Science

First Advisor

James Haney

Second Advisor

Alan Baker

Third Advisor

Jonathan Dufresne

Abstract

Russell Pond is an ultra-oligotrophic lake with low chlorophyll a (1.9 mg L-1), total phosphorus (3.4 mg L-1), high Secchi Disk (10.4 m) and high light transmission (water coefficient of water, kw=0.33). Vertical migration of Chaoborus, Bosmina, Daphnia, and copepods were examined using net collections of zooplankton discrete depth counts and sonar. Three contrasting patterns of vertical migration were observed in Russell Pond. Chaoborus punctipennis larvae vertical migration began at 7 pm and migrated through the entire lake water column, a total of 23 m from the sediments to the surface water in less than 4 hours, Bosmina had an epilimnetic migration, moving 3 m upward toward the surface between 4 and 6 pm but did not migrate further at 8 pm. Daphnia migrated downward (reverse migration) nearly 4 m, and the copepods did not migrate vertically. In contrast to the other macrozooplankton, the calanoid copepods staved in the deep epilimnion, with no detectable vertical displacement. The variation in vertical migration patterns in Russell Pond illustrate how this adaptive diel behavior is tailored to the differing selective pressures on the different zooplankton species.

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