Impact of environmental changes on ice seal ecology
Over the past decades, the Arctic has experienced some of the most rapid global warming, resulting in structural changes in sea-ice as well as in oceanographic physico-chemical parameters. This changes will impact organisms at every level of the Arctic food web from phytoplankton to top predators. Because of their position at the top of the marine food web and their close association with sea-ice, ice seals are considered bio-indicators of the ecosystem health. The sensitivity to the impacts of climate change on ice seals is expected to be species-specific. Hooded seals (Cystophora cristata) are considered highly sensitive to changes in sea ice conditions due to a high dependence to stable ice floes for whelping, lactation, and moulting (thermoregulation), and as foraging habitat. Hooded seals are listed as ‘Vulnerable’ by the International Union for Conservation of Nature (IUCN). The scarcity of Arctic ice seal demographic and movement data via biotelemetry (due to their remote habitat and logistical and financial difficulties to set up large scale field sessions) limits our ability to clearly understand the impacts of climate-induced changes on ice seal dynamics and distribution, and consequently limits our capacity to forecast the future viability of ice seals to adapt to climate and habitat change. This project seeks to first investigate the movement and foraging ecology hooded seals at different life stages to provide a better understanding of the mechanistic links between environmental changes and seals’ behavioural and ecological responses. Ultimately, understanding these links will allow us to forecast the impacts of projected climate scenarios on marine Arctic ecosystem functioning.
Funding and partners:
BNP Paribas foundation, Department of Fisheries and Oceans Canada, French Ministry of Higher Education and Research, CNRS, La Rochelle Uiversity, France-Canada Research Funds, ECOMM chaire
Impacts of oceanic changes on energetics, behaviours & life-history strategies of fur seals
The current impacts of climate changes on oceans are not homogenous worldwide: in sub-polar and temperate regions, marine ecosystems tend to experience a directional linear increase towards hotter environments, while tropical regions decrease in climate stability and predictability along with an increase in frequency of extreme climate events such as ENSOs and marine heatwaves. These rapid physical forcings will have a different impact on the structure and dynamics of food webs, right up to top predators, which as integrators of ecosystem changes from geochemical parameters to preyscape dynamics, are considered indicators of marine ecosystem health. The consequences of warming for long-lived top predators depends on their ability to respond to and survive changing in environmental patterns they are exposed to. As long-lived species are unlikely to show evolutionary responses at the rate to keep pace with climate change, behavioral plasticity is key for understanding these responses to environmental changes. In turn, these behavioural changes will impact diet and movements of individuals, their energetic cost/benefit ratios, and result in expressions of phenotypic and life history-trait plasticity. The main objective of this project is to determine how changes in physical and biological/trophic environments impact the behaviours, energetics and life history traits of fur seals in various locations. Specifically, how environmental variability and predictability shape individual strategies of fur seals given their acclimation and adaptive capacities, the consequences on fitness traits, and ultimately on population trajectories.
Funding and partners:
French Polar Institute IPEV, CNRS, La Rochelle University
Newly-developed microsonars and AI methods to analyze the underwater data they collect
Marine ecosystems are undergoing drastic and rapid changes due to anthropogenic pressures from intensive fishing, pollution, habitat loss, or global warming. The consequences of these changes on ecosystem functioning often remain poorly assessed, with only 5% addressing the overall question of the ecological consequences of these physical changes due to a persisting deficit of in situ-collected biological data. These gaps are primarily due to a lack of tools suitable for sampling intermediate trophic levels (i.e. nekton: zooplankton, gelatinous, fish and squid ...) simultaneously with the measurement of physical and biogeochemical oceanographic parameters at fine scales. In the last 20 years, animal-borne bio-logging devices, have revolutionized the study of animal behavior in their natural environments, and allowed to start bridging these data gaps. To that end, new underwater micro-cameras and a newly-developed micro-sonar that mimics the echolocation system of whales and dolphins, have been deployed on diving marine animals to record the presence of mid-trophic level organisms along the trajectory of diving marine predators . Moreover, the large and growing datasets generated by these loggers prohibit manual analysis in their entirety and as such require the development of accurate and relevant data processing methods based on machine learning to automatically extract relevant information from raw data.
Funding and partners:
CNRS, La Rochelle University, ECOMM chaire, CNES, French Polar Institute IPEV
Role of marine mammals in ocean nutrient cycling, and in sea-to land nutrient transfers
Nutrient cycling are a major component of ecosystem functioning. Essential nutrients accumulated in the ecosystem are released during the mineralization of organic matter by decomposers, making these elements available to plants. Thus, the nature of the accumulated organic matter and microbial diversity will direct the quality and quantity of mineral nutrients available to plants, governing more generally the structuring of the food web. Animals facilitate these transfers to primary producers by digesting essential elements stored in an unavailable form (slow-decomposing living organic matter) and releasing them in a more available form via the production of feces and urine. Their role in these biogeochemical fluxes, although poorly documented, is identified as significant and even structuring. Top predators in the oceans, such as cetaceans, have a significant role in these nutrient fluxes, which they collect via their food in the oceans, and recycle via their waste, enriching these same ecosystems. Seabirds, seals or sea lions on the other hand make regular trips back and forth between the marine environment where they feed and the land where they rest and reproduce. These journeys promote the transfer of nutrients from the sea to the land and contribute to the enrichment of terrestrial food chains.
Funding and partners:
CNRS, La Rochelle University, PELAGIS Observatory, University of Rennes
Steller sea lion nutritional physiology
Foraging ecology and bioenergetics of Northern and Antarctic fur seals
Foraging ecology of grey seals
Flight energetics of frigatebirds
Performances of Mote antennas to increase transmitted data return