SEDIMENTARY DNA AND PIGMENT RECORDS FROM TWO LAKES IN WASHINGTON STATE PARKS

Washington State, USA has had an opportunistic monitoring program for lake cyanotoxins since 2007. Two lakes, situated in state parks within the Puget Sound Region, have annual cyanobacteria blooms that cause the closure of public access to these lakes. Toxin concentrations in both lakes have been sufficient to cause wildlife and pet deaths. The hydrology of both lakes is dominated by groundwater inputs and both lakes have experienced some human impacts during the establishment of the parks. Here, we present sediment core records describing the algal pigment remains over the last ~150 years. In both lakes, carotenoids indicative of cyanobacteria were present throughout the sediment record, demonstrating that the natural geomorphic setting predisposes limnological conditions that support cyanobacteria. However, DNA analyses of the sediment record (qPCR and shotgun metagenome) revealed that the producers of the harmful levels of toxins currently in the lakes may be a more recent phenomenon. Possible climatic and fisheries management strategies are explored.

Primary Presenter: William Hobbs, Washington State Department of Ecology (whob461@ecy.wa.gov)

Authors:

Theo Dreher, Oregon State University  (theo.dreher@oregonstate.edu)

Rolf Vinebrooke, University of Alberta  (rolf@ualberta.ca)