EARTH, FIRE, AND WATER: USING PALEOLIMNOLOGY TO IDENTIFY DRIVERS OF CYANOBACTERIA ONSET IN SUBTROPICAL AND TROPICAL LAKES PRIOR TO THE ANTHROPOCENE

Cyanobacteria dominance in lake systems can occur in response to the modern impacts from humans and climate.  While substantial understanding of harmful algal bloom (HAB) dynamics has been accomplished through modern limnological investigations, historic data are needed to document the drivers and triggers linked to the beginning of cyanobacteria dominance, which frequently precede scientific study.  Here, we measured proxies linked to HABs (nutrients, pigments, cyanotoxins) on dated sediment cores from 6 lakes with a focus on the drivers triggering the onset of cyanobacteria dominance.  Results show that factors altering biogeochemical processes in lakes were as important as total nutrient concentrations.  For Lake Amatitlan, Guatemala and Lake Santa Julia, Mexico, erosional dynamics from ancient societies were the drivers of nutrient inputs and cyanobacteria onset, which also showed rapid recovery once human populations decreased.  However, for Ditch Pond Alabama, fire was the trigger causing excessive P inputs and HAB formation called “pyroeutrophication”.  Finally, for Lakes Apopka and Harris, Florida and Lake Mattamuskeet, NC, USA, alterations to hydrology was the primary trigger beginning cyanobacteria dominance.  For each system, cyanobacteria onset was linked to environmental change with most systems providing unique and novel scenarios.  Given that each of these systems represent “pristine” conditions prior to HAB formation and human impacts, these data show that HAB onset can be linked to specific environmental perturbations still occurring in the modern era.

Primary Presenter: Matthew Waters, Auburn University (mwaters@auburn.edu)

Authors:

Matthew Waters, Auburn University  (mwaters@auburn.edu)

Mark Brenner, University of Florida  (brenner@ufl.edu)

Jason Curtis, University of Florida  (curtisj@ufl.edu)

Savvas Paradeisis-Stathis, Auburn University  (szp0156@auburn.edu)

Savanna Wooten, Auburn University  (slw0093@auburn.edu)

Benjamin Webster, Auburn University  (bcw0030@auburn.edu)