On October 24, 2024, we were honored to welcome Dr. Katrine Turgeon from the University of Quebec, who shared her extensive research on how dams alter aquatic ecosystems’ biodiversity and trophic structures over time and space. Dr. Turgeon’s work bridges ecology, conservation, and socio-economic factors, making it highly relevant to current environmental challenges.
Key Takeaways from the Seminar
The “Hump-Shaped” Response in Predatory Fish:
- Dr. Turgeon’s research revealed that dams cause notable shifts in fish populations, particularly among predatory species. The “hump-shaped” response pattern shows a peak in biomass followed by a decline, a critical indicator for understanding ecosystem stability.
- This pattern was most evident in pike species, where pre-impoundment levels have not fully recovered, highlighting the long-term effects of dam-induced changes.
Regional Differences in Impact:
- Tropical ecosystems show more pronounced biodiversity changes compared to boreal regions, underscoring the need for region-specific conservation strategies.
- In Quebec, boreal ecosystems have demonstrated resilience to certain disturbances, while tropical regions require more focused efforts to mitigate biodiversity loss.
Conservation, First Nations, and Mercury Contamination
A critical aspect of Dr. Turgeon’s seminar was the intersection of conservation and Indigenous rights, particularly how mercury contamination in fish affects First Nations communities. Dams not only alter aquatic ecosystems but also cause the release and subsequent bio-accumulation (through cannibalism in predatory fish) of methylmercury, a potent neurotoxin, into the water.
Mercury accumulation has severe consequences for local fish populations, leading to bioaccumulation and biomagnification, especially in predatory species like pike. This poses a significant health risk to First Nations communities, who rely on these fish as a primary food source. Pregnant women and infants are especially vulnerable, as mercury exposure can have long-lasting neurological impacts.
Dr. Turgeon emphasized the need for conservation strategies that not only restore and protect aquatic biodiversity but also respect and prioritize the cultural and dietary traditions of First Nations communities.
Challenges and Advice for Aspiring Researchers
Dr. Turgeon shared her journey from postdoc to professor, candidly discussing unexpected challenges, such as increased administrative responsibilities and budget management. She recommends student’s to not be mere ’lab-rats’ blindly following their supervisor’s instructions and instead think for themselves, while actively engaging their community and diversifying their skillset.
Research Highlights
- Trophic Surge Hypothesis: Dr. Turgeon explained how nutrient levels and fish populations experience a transient phase of instability during dam construction, known as the Trophic Surge Hypothesis.
- Inverted Food Pyramid in Reservoirs: A surprising finding was the inverted food pyramid observed in some reservoirs.
Socio-Ecological Context
Dr. Turgeon’s study isn’t limited to biological implications. It also addresses socio-economic factors, such as how energy needs and cultural sites intersect with environmental goals.
Looking Ahead
Dr. Turgeon envisions a future where human dimensions are integral to ecological research and urges aspiring reseasrhers in her field to engage the citizens more, by learning how to simplify complex scientific concepts based on their target audiences, thereby helping shape public policy.
For more in-depth insights, connect with me on LinkedIn and join the conversation!