Lab

Philippe Archambault's Lab

Institution: Laval University

Featured projects (1)

Project
Human-driven changes are occurring at an alarming rate on global scales and threaten coastal habitats in the Arctic. Kelps are large brown seaweeds that form unique habitats along many rocky Arctic coasts. Many fish and other animals use these lush underwater forests or shelter and food, which are particularly striking along Arctic coasts where ice scour and harsh climate leave the nearby land barren with little vegetation. Kelp forests have been recorded throughout the Canadian Arctic, yet we know little of these habitats, and their fate in this era of rapid change represents a critical gap in our knowledge of Arctic coastal ecosystems. Research to date suggest that a warmer Arctic with less sea ice may increase the extent of kelp by providing extended periods of light and warmer waters for growth. However, melting sea ice and permafrost may offset this benefit by freshening and increasing water color and turbidity in coastal areas. This project will combine coastal surveys, scientific dive experiments, laboratory tests, community meetings, remote sensing, research cruises, and modelling approaches to map kelp forests in the Arctic, assess their importance for coastal ecosystems and coastal societies, and predict climate-driven impacts on them. Knowledge on Arctic kelp forests will help northern communities and societies anticipate and prepare for coastal changes and possibly even benefit from these new ecosystems.

Featured research (14)

The Green Edge project was designed to investigate the onset, life, and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in Arctic Ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocean food chain, it is crucial to understand how changes in the Arctic environment will affect it. Green Edge was a large multidisciplinary, collaborative project bringing researchers and technicians from 28 different institutions in seven countries together, aiming at understanding these changes and their impacts on the future. The fieldwork for the Green Edge project took place over two years (2015 and 2016) and was carried out from both an ice camp and a research vessel in Baffin Bay, in the Canadian Arctic. This paper describes the sampling strategy and the dataset obtained from the research cruise, which took place aboard the Canadian Coast Guard ship (CCGS) Amundsen in late spring and early summer 2016. The sampling strategy was designed around the repetitive, perpendicular crossing of the marginal ice zone (MIZ), using not only ship-based station discrete sampling but also high-resolution measurements from autonomous platforms (Gliders, BGC-Argo floats …) and under-way monitoring systems. The dataset is available at https://doi.org/10.17882/86417 (Bruyant et al., 2022).
Evaluating the effects of multiple stressors on ecosystems is becoming increasingly vital with global changes. The role of species interactions in propagating the effects of stressors, although widely acknowledged, has yet to be formally explored. Here, we conceptualise how stressors propagate through food webs and explore how they affect simulated three‐species motifs and food webs of the Canadian St. Lawrence System. We find that overlooking species interactions invariably underestimate the effects of stressors, and that synergistic and antagonistic effects through food webs are prevalent. We also find that interaction type influences a species’ susceptibility to stressors; species in omnivory and tri‐trophic food chain interactions in particular are sensitive and prone to synergistic and antagonistic effects. Finally, we find that apex predators were negatively affected and mesopredators benefited from the effects of stressors due to their trophic position in the St. Lawrence System, but that species sensitivity is dependent on food web structure. In conceptualising the effects of multiple stressors on food webs, we bring theory closer to practice and show that considering the intricacies of ecological communities is key to assess the net effects of stressors on species. The role of species interactions in propagating the effects of stressors, although widely acknowledged, has yet to be formally explored. Here, we conceptualise how stressors propagate through food webs and we find that overlooking species interactions invariably underestimate the effects of stressors. In conceptualising the effects of multiple stressors on food webs, we bring theory closer to practice and show that considering the intricacies of ecological communities is key to assess the net effects of stressors on species.
With the widespread influence of human activities on marine ecosystems, evaluation of ecological status provides valuable information for conservation initiatives and sustainable development. To this end, many environmental indicators have been developed worldwide and there is a growing need to evaluate their performance by calculating ecological status in a wide range of ecosystems at multiple spatial and temporal scales. This study calculated and contrasted sixteen indicators of ecological status from three methodological categories: abundance measures, diversity parameters and characteristic species. This selection was applied to coastal benthic ecosystems at Sept-Îles (Québec, Canada), an important industrial harbor area in the Gulf of St. Lawrence, and related to habitat parameters (organic matter, grain size fractions, and heavy metal concentrations). Nearly all indicators highlighted a generally good ecological status in the study area, where communities presented an unperturbed profile with high taxa and functional diversities and without the dominance of opportunistic taxa. Some correlations with habitat parameters were detected, especially with heavy metals, and bootstrap analyses indicated quite robust results. This study provides valuable information on the application of environmental indicators in Canadian coastal ecosystems, along with insights on their use for environmental assessments.
A simplified model, representing the dynamics of marine organic particles in a given size range experiencing coagulation and fragmentation reactions is developed. The framework is based on a discrete size spectrum on which reactions act to exchange properties between different particle sizes. The reactions are prescribed according to triplets interactions. Coagulation combines two particle sizes to yield a third one, while fragmentation breaks a given particle size into two (i.e. the inverse of the coagulation reaction). The complete set of reactions is given by all the permutations of two particle sizes associated with a third one. Since, by design, some reactions yield particle sizes that are outside the resolved size range of the spectrum, a closure is developed to take into account this unresolved range and satisfy global constraints such as mass conservation. In order to minimize the number of tracers required to apply this model to an Ocean General Circulation Model focus is placed on the robustness of the model to the particle size resolution. Thus, numerical experiments were designed to study the dependence of the results on i) the number of particle size bins used to discretize a given size range (i.e. the resolution) and ii) the type of discretization (i.e. linear vs nonlinear). The results demonstrate that in a linearly size discretized configuration, the model is independent of the resolution. However, important biases are observed in a nonlinear discretization. A first attempt to mitigate the effect of nonlinearity of the size spectrum is then presented and shows significant improvement in reducing the observed biases.
ABSTRACT: Understanding the mechanisms that support feeding interactions and species cooccurrence in regions subject to rapid environmental changes is becoming increasingly important to predict future trends in population dynamics. However, there is still little information available on the trophic ecology for many benthic species to help us better understand trophic interactions and individual trophic roles. Here, we used stable isotopes (δ13C, δ15N) in conjunction with the Bayesian ellipses approach to explore spatial trends in isotopic niche width and overlap of 3 syntopic arctic brittle stars (Echinodermata: Ophiuroidea; Ophiacantha bidentata, Ophiocten sericeum, and Ophiopleura borealis) in Baffin Bay (BB), the Canadian Arctic Archipelago (CAA), and the North Water Polynya (NOW). These 3 coexisting ophiuroids displayed great interspecific plasticity in foraging behaviors and showed a high degree of inter-individual dietary flexibility. However, differences in surface carbon composition drove the variability of resource utilization at the individual level across stations, which in turn affected trophic interactions, niche overlaps, and isotopic niche breadth of ophiuroids. Greater niche overlap was found in the highly productive region of the NOW, where consumers exhibited similar food selectivity, whereas an increase in niche segregation occurred in regions with greater sea-ice concentration. These results suggest that isotopic niche size reflects individual responses to fluctuations in food availability and possibly past competition, both induced by local oceanographic features. Our study indicates that niche parameters of ophiuroids can respond quickly to ecological and environmental gradients, which suggests important adaptability of these species facing multiple stressors.

Lab head

Philippe Archambault
Department
  • Department of Biology
About Philippe Archambault
  • Philippe Archambault currently works at the Department of Biology, Laval University. Philippe does research in Marine Biology and Ecology. Their current project is 'Understanding the cumulative impacts of human activities on the structure and function of the benthic ecosystems in Arctic and subarctic.'

Members (14)

Karen Filbee-dexter
  • University of Western Australia
Cindy Grant
  • Laval University
Jesica Goldsmit
  • Fisheries and Oceans Canada
David Beauchesne
  • University of Toronto
Laure de Montety
  • Marine and Freshwater Research Institute/ Hafrannsóknastofnun
Lisa Treau De Coeli
  • Laval University
Gustavo Yunda-Guarin
  • Memorial University of Newfoundland

Alumni (1)

Elliot Dreujou
  • Northern Institute for Research in Environment and Occupational Health and Safety