Presentation Title

The Effects of Hypoxia on Zooplankton Population Estimates and Migration in Lakes

Project Collaborators

Jon Doubek (Collaborating Mentor)

Abstract

Zooplankton are small animals that live in aquatic environments and play an important ecological role as primary consumers. Many zooplankton species typically exhibit diel vertical migration (DVM) in lakes, where they avoid visual predators and UV radiation by remaining in the hypolimnion (bottom waters) during the day and ascending to the epilimnion (surface waters) to feed on phytoplankton at night. However, hypoxic conditions in the hypolimnion of lakes may interfere with DVM and force zooplankton to increase diel horizontal migration (DHM) to find predation refuge in nearshore zones. Climate change and eutrophication are expected to increase the prevalence and severity of hypoxic conditions worldwide and thereby possibly alter zooplankton migration patterns. We hypothesized that hypoxia will force zooplankton to shift their migration patterns from predominantly DVM to DHM to avoid oxygen-depleted bottom waters. To test our hypothesis, we conducted a standardized global sampling program to evaluate whether pelagic, full water column estimates of zooplankton are greater at night versus the day under hypolimnetic hypoxic versus oxic conditions. Participants attempted to sample at least one lake with an oxic hypolimnion and one lake with a hypoxic hypolimnion during the thermally-stratified period at midday and midnight. With our global dataset (currently expecting about 60 lakes in 22 countries), our goal is to improve our understanding of how global change may alter zooplankton migration behavior and patterns in lakes.

Primary Faculty Mentor Name

Jason Stockwell

Status

Undergraduate

Student College

Rubenstein School of Environmental and Natural Resources

Program/Major

Environmental Sciences

Primary Research Category

Food & Environment Studies

Secondary Research Category

Biological Sciences

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The Effects of Hypoxia on Zooplankton Population Estimates and Migration in Lakes

Zooplankton are small animals that live in aquatic environments and play an important ecological role as primary consumers. Many zooplankton species typically exhibit diel vertical migration (DVM) in lakes, where they avoid visual predators and UV radiation by remaining in the hypolimnion (bottom waters) during the day and ascending to the epilimnion (surface waters) to feed on phytoplankton at night. However, hypoxic conditions in the hypolimnion of lakes may interfere with DVM and force zooplankton to increase diel horizontal migration (DHM) to find predation refuge in nearshore zones. Climate change and eutrophication are expected to increase the prevalence and severity of hypoxic conditions worldwide and thereby possibly alter zooplankton migration patterns. We hypothesized that hypoxia will force zooplankton to shift their migration patterns from predominantly DVM to DHM to avoid oxygen-depleted bottom waters. To test our hypothesis, we conducted a standardized global sampling program to evaluate whether pelagic, full water column estimates of zooplankton are greater at night versus the day under hypolimnetic hypoxic versus oxic conditions. Participants attempted to sample at least one lake with an oxic hypolimnion and one lake with a hypoxic hypolimnion during the thermally-stratified period at midday and midnight. With our global dataset (currently expecting about 60 lakes in 22 countries), our goal is to improve our understanding of how global change may alter zooplankton migration behavior and patterns in lakes.