15 research outputs found
The effects of hypoxia on zooplankton population estimates and migration in lakes
Many zooplankton species typically exhibit diel vertical migration (DVM), where
zooplankton migrate from the hypolimnion to the epilimnion of lakes at night.
Zooplankton exhibit this behavior to avoid visual predators and UV radiation by
remaining in the bottom waters during the day and ascending to the surface waters to feed
on phytoplankton at night. However, hypoxic conditions in the hypolimnion of lakes mayinterfere with DVM and force zooplankton to increase diel horizontal migration (DHM)
to find predation refuge in littoral 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 hypothesize 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 are conducting a standardized
global sampling program to test whether pelagic, full water column estimates of
zooplankton are greater at night versus the day under hypolimnetic hypoxic versus oxic
conditions. Participants are aiming 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.info:eu-repo/semantics/publishedVersio