Zooplankton interaction with summer cyanobacteria blooms in Lake Erie’s Presque Isle Bay, 2016-17

Session: 41a. - Great Lakes Harmful Algal Blooms Research from Watershed Influence to Ecosystem Effects

J. Campbell, Mercyhurst University, [email protected]
H. Rick Diz, retired-Gannon University, [email protected]

Abstract

The plankton community of Lake Erie’s Presque Isle Bay was sampled biweekly from June through mid-September 2016 and 2017, to obtain data necessary to refine an ecosystem model for predicting blooms of cyanobacteria. Net phytoplankton and zooplankton were assessed with triplicate vertical tows of a 65-micron mesh Wisconsin-style plankton net. Nannoplankton was quantified with whole water samples preserved in Lugol’s iodine and concentrated by sedimentation. Abundance of Daphnia species was highest in mid-June both years and then decreased when the summer cyanobacteria bloom (CB) of Microcystis, Anabaena, Aphanizomenon and Lyngbya developed in late July and August. Several species of rotifers and the littoral cladoceran Chydorus increased in abundance during the CB. The colonial diatom Aulacoseira persisted as a co-dominant taxon with cyanobacteria both summers. The net phytoplankton of Presque Isle Bay in summer were probably not directly utilized by feeding zooplankton but may benefit some of the zooplankton taxa by supporting smaller edible epiphytic flagellates and bacteria produced when blooms collapse and decompose. CBs in the bay appear to be more related to temperature/day-length changes than to biotic factors related to the zooplankton community.

1. Keyword
cyanophyta

2. Keyword
zooplankton

3. Keyword
Lake Erie

4. Additional Keyword
Presque Isle Bay

5. Additional Keyword
net phytoplankton