DO ALL CYANOBACTERIA WIN? USING PALEOLIMNOLOGICAL APPROACHES TO DISENTANGLE THE LONG-TERM NUTRIENT AND CLIMATE DRIVERS OF HARMFUL CYANOBACTERIA BLOOMS

Paleo, contemporary, and modeling-based limnological studies have documented and forecasted global increases in harmful cyanobacterial blooms, suggesting that cyanobacteria will be climate change “winners”. Characterizing the strength of nutrients and temperature as drivers of cyanobacterial blooms is complicated by differences in species’ responses to environmental change and insufficiently long time series. We employ a multiproxy paleolimnological approach using photosynthetic pigments and environmental DNA (eDNA) metabarcoding to investigate cyanobacteria in Maine lakes that span different climate zones and trophic states. These sediment reconstructions can be used to disentangle the effects of nutrients, temperature, and their interactions on cyanobacterial communities in Maine lakes over the past 125 years. Specifically, we address: 1. Are nutrients or temperature a better predictor of cyanobacterial abundance and diversity in Maine’s temperate lakes? 2. Do nutrients and temperature interact to affect cyanobacterial abundance and diversity, and if so, how? Results will help to further characterize climate “winners”, determine any timing/direction/magnitude of algal community change, and better clarify whether Maine lake ecosystems are moving outside their natural variability. Pairing paleolimnological proxies, including eDNA approaches, over long timescales contributes to a more precise understanding of climate change effects on cyanobacterial taxa and underscores the importance of paleolimnological records in assessing effects of climate change on lake systems.

Presentation Preference: Oral

Primary Presenter: Avery Lamb, University of Maine (avery.lamb@maine.edu)

Authors:

Avery Lamb, University of Maine  (avery.lamb@maine.edu)

Robin Sleith, Bigelow Laboratory for Ocean Sciences  (rsleith@bigelow.org)

Peter Countway, Bigelow Laboratory for Ocean Sciences  (pcountway@bigelow.org)

Suzanne McGowan, Netherlands Institute of Ecology  (S.McGowan@nioo.knaw.nl)

Andrew Rominger, University of Hawaii at Manoa  (rominger@hawaii.edu)

Michael Kinnison, University of Maine  (mkinnison@maine.edu)

Jasmine Saros, University of Maine  (jasmine.saros@maine.edu)