Étudiant-chercheur étoile July 2015



Matthew Bogard

PhD student in Biological Sciences
Université du Québec à Montréal


Award-winning publication: Oxic water column methanogenesis as a major component of aquatic CH4 fluxes

Published in: Nature Communications
 

Abstract

"Methane (CH4) is one of the most patent greenhouse gases in the atmosphere, but its sources and controls are poorly understood. One of the greatest knowledge gaps in the global CH4 cycle is its regulation in aquatic environments and aquatic contributions to global atmospheric emissions. Traditionally, it is assumed that CH4 is produced exclusively by microorganisms in anoxie (oxygen-free) deep water and sediment environments. Here, we dispel this assumption and advance the understanding of the aquatic CH4 cycle by demonstrating CH4 is produced in oxygen-rich surface water. We establish a previously unconsidered, mechanistic link between the dynamics of aquatic algal growth and CH4 production in surface waters, and confirm that this pathway is a significant component of total lake CH4 emissions. We combined existing literature data to show that this oxic water CH4 production might actually be the main source for CH4 emissions both in large, deep lakes, and in the oceans. Our findings have very broad implications for a wide, multi-disciplinary audience in the fields of biogeochemistry, ecology, microbiology, climatology and environmental modeling."

This study has clear long-term implications for our understanding and adaptation to changes in climate that are linked to methane (CH4) dynamics, because CH4 accounts for roughly 20% of all planetary warming, and its atmospheric concentrations are increasing in recent decades. This work also provides new insight into how human activities may shape greenhouse gas concentrations in the atmosphere, since it establishes a previously unconsidered link between CH4 emissions and the growth of algae, and algae are strongly influenced by nutrient pollution (eutrophication), human manipulation of the food web, and a series of other factors linked to human activity. As a result, Matthew Bogard's study helps to predict how CH4 fluxes from aquatic systems will respond under future scenarios of human-driven environmental changes and management decisions.