Using Integrated Environmental Change Study Methods to Understand Factors Influencing Harmful Algae Blooms in a Rural Headwater Lake

Abstract

Eutrophication and algae production are an important lake management issue in rural Nova Scotia. In the past decade, there have been increasing instances of harmful algae bloom (HAB) events in previously unaffected surface water systems. Three major toxic cyanobacteria bloom events of Dolichospermum planctonicum were observed in Mattatall Lake in Cumberland County in 2014, 2015 and 2016. The bloom events were considered unprecedented for Mattatall Lake because it is a rural headwater lake where this level of productivity had not been observed before. This project utilized a multifaceted approach to studying the environmental changes at Mattatall Lake to parse what factors, cumulative or recent, might have contributed to the HAB events. A multiproxy paleolimnological assessment, in combination with historic climate and land use analysis, water quality monitoring, and comparison to a nearby reference site with no history of algae blooms was applied.