Assessing the drivers of biodiversity

In a context of multiple environmental pressures, aquatic biodiversity responses are studied across different levels of biological organization and spatial scales, ranging from local to global.

1. Local scale

At the local scale, research focuses on phytoplankton community responses to re-oligotrophication and climate change, using statistical analyses and modelling approaches (including 3D models) to develop predictive tools. This includes assessing the combined effects of increasing temperatures and reduced food availability (i.e., zooplankton), in relation to re-oligotrophication processes and/or invasion by the genus Dreissena.

2. National scale

At the national scale, the work evaluates how lake trophic status and oxygenation influence methanogenic archaeal communities, including their abundance and metabolic potential. It also investigates the consequences of environmental conditions on methane-derived carbon transfer within benthic and pelagic food webs, mediated by methanogenic archaea.

3. Global scale

At the global scale, the aim is to understand the impact of climate change on zooplankton communities and whitefish (coregonid) populations, based on long-term collaborative networks established by CARRTEL scientists (notably within GLEON). This research evaluates the roles of both direct thermal forcing (e.g., spring and summer temperatures) and indirect effects (e.g., resource phenology) in shaping organism dynamics at a planetary scale.

Using IPCC climate scenarios, forward-looking analyses are also conducted to estimate the vulnerability of these organisms to future climate change.

4. Pollution impacts across biological scales

The impact of multiple pollutants is assessed across different levels of biodiversity (from individuals to communities), integrating life-history traits, functional traits, and genetic markers across micro- and macro-organisms. This is done through a combination of controlled experiments and in situ studies.

4.1 6PPD-quinone

This research aims to better understand the effects of 6PPD-quinone, an aquatic pollutant derived from tire wear particles, on fish and macroinvertebrates.

4.2 Pharmaceutical compounds

This work evaluates the impact of pharmaceutical substances on microorganisms, with a focus on how opportunistic bacteria contribute to horizontal gene transfer and promote the spread of virulence factors and antibiotic resistance genes.

Specific research goals currently at work can be summed up as follows: 

> Quantify the impacts of climate change and specifically changes of the thermal structure on pelagic communities through lake-specific and multi-lake approaches
> Identify key patterns of biodiversity dynamics (reference states, turn-over and tipping points) and relate them to environmental and anthropogenic drivers
> Determine the responses of littoral ecological communities to local and global stressors
> Fish population responses to global and local changes
> Focus on cyanobacterial blooms