Actualités et séminaires

Rapid warming since the 19th century is transforming the Arctic, including its freshwater ecosystems as warmer temperatures and greater nutrient inputs from a greening landscape are increasing lake and pond productivity. However, nutrients from growing avian nesting colonies can have a much greater effect on aquatic primary production, as undisturbed Arctic catchments have relatively low nutrient inputs. Therefore, a more complete assessment of climate warming’s influence on Arctic aquatic primary production should consider how warming may influence avian population dynamics.

The Ox Bel’Ha and Sac Actun karstic systems are among the longest coastal cave systems in the world. These systems are located around and below the city of Tulum on the east side of the Yucatan peninsula. Divers have explored and mapped them for years and obtained detailed topographical information. The caves are mainly shallow (15-30 m below surface) and form a dense network of submerged caves directly outflowing to the ocean. The rapid urban development of Tulum goes with decreasing groundwater quality in the karstic system and a new threat for the coral reef and its biodiversity.

Hydrothermal geysers are visually engaging geomorphic features that represent a rapid and occasionally violent release of energy manifested as hydrothermal fluids/vapors launched skyward. Although not completely rare worldwide, hydrothermal geysers intrigue humans now and throughout history. Fortunately for us, Yellowstone National Park is home to roughly 500 geysers, making it the most concentrated geyser field in the world. Yet, the dynamics of geyser eruptions are uncertain. Much of this uncertainty stems from a lack of knowledge of their subsurface structure.

Les écosystèmes aquatiques sont particulièrement exposés aux pollutions d’origine urbaine et agricole. De manière intrigante, certains parasites intestinaux, les acanthocéphales, présentent la remarquable capacité d'accumuler des polluants depuis leur hôte. Ces parasites peuvent s’avérer utiles pour leur poisson-hôte si les bénéfices associés à la séquestration des polluants, et donc à l’atténuation des effets écotoxicologiques, contrebalancent les coûts de l’infection parasitaire.