Env. science student studies algae blooms in lakes

Margaux Daly analyzes New Brunswick lake sediments to determine blooms through time

Algae blooms are one of the biggest environmental concerns in North America, and some New Brunswick lakes are succumbing to their harmful effects. Fourth-year honours student Margaux Daly is researching how algae blooms affect the past and present ecology of New Brunswick lakes under the supervision of Joshua Kurek, an associate professor in the department of geography and environment. Daly’s research may have implications to the control and management of algae blooms in New Brunswick lakes.

“Algae blooms […] are signals of environmental stress,” said Daly. “So the project is about determining characteristics of lakes that are sensitive to environmental stressors, and that helps us better manage the lakes in the future.” Algae blooms are massive surface-water growths of blue-green algae. This phenomenon is mainly caused by eutrophication, a process in which a body of water accumulates a high concentration of chemical nutrients. Sewage containing agricultural and industrial waste often leads to stronger and more frequent blooms. Algae blooms produce natural toxins which endanger aquatic organisms and have severe impact on human health. They also deplete oxygen in the water, creating a stressful environment for species living in the area.

Daly is studying the ecological systems of three lakes located throughout New Brunswick: Lac Unique, First Lake and States Lake. Lac Unique is the only one of these lakes Daly’s honours research took her to several New Brunswick lakes. Margaux Daly/Submitted experiencing algae blooms. Daly collected sediment samples from their deepest locations, using a sediment core collector from a boat. The sediment samples, which contain layers of minerals and different types of bacteria, provide records of long-term climate changes. From these samples, Daly obtains the fossils of a type of freshwater crustacean called cladocera, also known as the water flea. This organism indicates changes of the lakes’ food webs due to their high sensitivity to various environmental stressors. Daly analyzes and compares the cladoceran population structures across the three lakes. The results from her analysis are used as a proxy to understand and construct climate records of the environmental changes in the lakes.

Daly said the results she has obtained so far indicate the lakes are experiencing a loss of species richness over time, with Lac Unique experiencing the greatest loss.

“[T]here is clearly something different about [Lac Unique] that is making it more susceptible to climate change than the reference sites [State Lake and First Lake], likely because it is closer to anthropogenic activities than the other two lakes,” said Daly.

“When intense algae blooms are occurring, species that can withstand these conditions or even thrive in them will become more successful and species that are less suited to those conditions become less abundant or completely die out,” she said.

Daly said she developed her interest in environmental studies from camping and canoe trips. “I have a certain appreciation and care for the environment. I think the science of ecology and population structure is really interesting. It is really cool […] how little changes can have such a big impact and how well suited the environment is to changes.”