Interview with Professor Jean-Éric Tremblay

In this interview, Professor Jean-Éric Tremblay (Université Laval) presents his work on nutrient dynamics in the St. Lawrence system, from the riverine part to the Gulf. His research reveals a major change in the ecosystem: while phosphorus inputs have been controlled over time, nitrogen inputs have increased significantly due to the use of agricultural fertilizers, altering the overall nutritional balance. The study highlights a marked seasonal dynamic, where continental nutrients spread very far into the Gulf during winter in the absence of assimilation by phytoplankton, fueling the spring bloom, while in summer, they are rapidly absorbed in the estuary. To ensure sustainable management of the river and counter phenomena such as hypoxia, he advocates better control of nitrogen discharges upstream, increased integration of research into economic development, and strengthened awareness among the general public and future maritime stakeholders.