These are some of our major research lines. Examples of projects are described in our profiles
Filter-feeder trophic interactions
Filter-feeder trophic interactions reveal the impact of this group on ecosystem functioning. We have demonstrated the different ecological niches of several species of filter-feeders (bivalves and tunicates) that co-exist in the same habitat using stable isotopes and in situ experiments at the individual level. We have constructed models that predict that cultured filter-feeders can exert a top-down and bottom-up control on phytoplanktonic community structure via feeding and ammonia excretion, respectively. Finally, combining field experiments on capture efficiency and individual-based modelling, we have estimated for the first time the potential contribution of picoplankton to the energetics of the mussel Mytilus edulis. We are currently working on new hypotheses on the capture mechanisms of filter-feeders
Filter-feeder trophic interactions reveal the impact of this group on ecosystem functioning. We have demonstrated the different ecological niches of several species of filter-feeders (bivalves and tunicates) that co-exist in the same habitat using stable isotopes and in situ experiments at the individual level. We have constructed models that predict that cultured filter-feeders can exert a top-down and bottom-up control on phytoplanktonic community structure via feeding and ammonia excretion, respectively. Finally, combining field experiments on capture efficiency and individual-based modelling, we have estimated for the first time the potential contribution of picoplankton to the energetics of the mussel Mytilus edulis. We are currently working on new hypotheses on the capture mechanisms of filter-feeders
Bioenergetic modelling
The flow of energy through individuals is critical not only to predict growth and reproduction potential but also to understand the effects of populations on biogeochemical processes at the ecosystem level. We have extensively compared the strengths and weaknesses of the two main bioenergetic models, Scope For Growth and Dynamic Energy Budget (DEB) (empirical and mechanistic principles, respectively). Given the mechanistic nature of DEB, I have embraced this theory as the state-of-the-art framework to model individual bioenergetics. We have constructed two new DEB models for the oyster Crassostrea virginica, and the freshwater fish Umbra limi to explore the effects of environmental drivers on individual growth. Despite the fact that DEB is an individual-based model, we can translate the inter-individual variability to a population model aiming towards a more realistic simulation of ecosystem processes. We are currently working on new bioenergetic models for Atlantic salmon and tunicates
The flow of energy through individuals is critical not only to predict growth and reproduction potential but also to understand the effects of populations on biogeochemical processes at the ecosystem level. We have extensively compared the strengths and weaknesses of the two main bioenergetic models, Scope For Growth and Dynamic Energy Budget (DEB) (empirical and mechanistic principles, respectively). Given the mechanistic nature of DEB, I have embraced this theory as the state-of-the-art framework to model individual bioenergetics. We have constructed two new DEB models for the oyster Crassostrea virginica, and the freshwater fish Umbra limi to explore the effects of environmental drivers on individual growth. Despite the fact that DEB is an individual-based model, we can translate the inter-individual variability to a population model aiming towards a more realistic simulation of ecosystem processes. We are currently working on new bioenergetic models for Atlantic salmon and tunicates
Carrying capacity modelling
The concept of carrying capacity is commonly used in shellfish aquaculture to establish the limits for sustainable production. Although carrying capacity has been explored using ecosystem models since the 90s, we have been pioneers in operationalizing these models by defining objective thresholds of sustainability. We base these thresholds on the natural variability of the ecosystem, an approach that applies the concepts of ecological resilience and the precautionary principle. We also led the application of mathematical algorithms to objectively optimize the spatial arrangement of aquaculture facilities to maximize aquaculture production while guaranteeing ecosystem sustainability. Using these models, we have confirmed the central role of coastal hydrodynamics in ecosystem functioning and demonstrated an inverse relationship between water residence time and ecological resilience in shellfish aquaculture sites. We have also explored the use of food web modelling to infer resilience and functional diversity to inform carrying capacity. We are currently working on novel ways to effectively incorporate our models into management.
The concept of carrying capacity is commonly used in shellfish aquaculture to establish the limits for sustainable production. Although carrying capacity has been explored using ecosystem models since the 90s, we have been pioneers in operationalizing these models by defining objective thresholds of sustainability. We base these thresholds on the natural variability of the ecosystem, an approach that applies the concepts of ecological resilience and the precautionary principle. We also led the application of mathematical algorithms to objectively optimize the spatial arrangement of aquaculture facilities to maximize aquaculture production while guaranteeing ecosystem sustainability. Using these models, we have confirmed the central role of coastal hydrodynamics in ecosystem functioning and demonstrated an inverse relationship between water residence time and ecological resilience in shellfish aquaculture sites. We have also explored the use of food web modelling to infer resilience and functional diversity to inform carrying capacity. We are currently working on novel ways to effectively incorporate our models into management.
Coastal connectivity
Hydrodynamics play a critical role in coastal ecosystem functioning and consequently is central in aquaculture research. We have developed a series of spatially-explicit ecosystem models coupling hydrodynamic to biogeochemical models. In order to facilitate this coupling, we have developed a flexible coupling framework that is able to assimilate the outcomes of different hydrodynamic models such as AquaDyn, RMA or FVCOM. This framework also allows for a probabilistic approach to characterize coastal connectivity based on the Markov chains theory. The framework builds upon the post-processing of hydrodynamic modelling outcomes and the construction of transition probability matrices that can be coupled to specific algorithms to calculate indicators of coastal connectivity such as transfer time or transfer rate. This approach has allowed us to explore coastal connectivity and potential interactions among shellfish farms. We are currently working on the applications of coastal connectivity to aquatic disease transmission.
Hydrodynamics play a critical role in coastal ecosystem functioning and consequently is central in aquaculture research. We have developed a series of spatially-explicit ecosystem models coupling hydrodynamic to biogeochemical models. In order to facilitate this coupling, we have developed a flexible coupling framework that is able to assimilate the outcomes of different hydrodynamic models such as AquaDyn, RMA or FVCOM. This framework also allows for a probabilistic approach to characterize coastal connectivity based on the Markov chains theory. The framework builds upon the post-processing of hydrodynamic modelling outcomes and the construction of transition probability matrices that can be coupled to specific algorithms to calculate indicators of coastal connectivity such as transfer time or transfer rate. This approach has allowed us to explore coastal connectivity and potential interactions among shellfish farms. We are currently working on the applications of coastal connectivity to aquatic disease transmission.
Ecological indicators of ecosystem functioning
The implementation of adaptive management requires cost-effective monitoring strategies to evaluate the performance of the management plan. Consequently, managers and policy-makers require objective ecological indicators. Using a meta-analysis covering 31 bays of Eastern Canada, we have demonstrated that bivalve condition index is a robust indicator of aquaculture activity, after which we defined a framework for monitoring using bivalve performance as indicator of ecosystem health. We have proposed monitoring mussel shell growth over time as an early warning indicator of critical transitions in aquaculture sites. We have demonstrated the application of these ideas to different ecosystems such as freshwater streams, using the growth of a generalist fish Umbra limi as indicator. We are currently working on the definition of thresholds and the implementation of indicators into management tools for objective decision making.
The implementation of adaptive management requires cost-effective monitoring strategies to evaluate the performance of the management plan. Consequently, managers and policy-makers require objective ecological indicators. Using a meta-analysis covering 31 bays of Eastern Canada, we have demonstrated that bivalve condition index is a robust indicator of aquaculture activity, after which we defined a framework for monitoring using bivalve performance as indicator of ecosystem health. We have proposed monitoring mussel shell growth over time as an early warning indicator of critical transitions in aquaculture sites. We have demonstrated the application of these ideas to different ecosystems such as freshwater streams, using the growth of a generalist fish Umbra limi as indicator. We are currently working on the definition of thresholds and the implementation of indicators into management tools for objective decision making.
Climate change impacts on coastal ecosystems
We have combined field observations and ecosystem modelling to investigate the effects of climate change on coastal ecosystems at the individual and ecosystem levels. Using long-term time series, we have demonstrated that the phenology of mussel larvae is changing, driven by the concomitant increase of ocean temperature in embayments of PEI. The influence of water temperature on the metabolism of poikilothermic organisms is critical for population dynamics, as we demonstrated for the non-indigenous bryozoan Membranipora membranacea. Although temperature is the main climate change driver, there are other drivers that can exert a significant effect on ecosystem functioning. For example, storms and hurricanes can alter coastal geomorphology and hydrodynamics, and consequently ecosystem functioning, as we demonstrated in an estuarine-scale experiment using field and modelling data pre- and post-storm. We have also used ecosystem modelling to forecast long-term climate change effects such as (1) the increase in mussel aquaculture production in St. Peter’s Bay driven by temperature and nutrient discharge via precipitation; (2) the competitive advantage of oysters vs mussels in a warming ocean due to different thermal tolerances; and (3) the differential resilience of coastal embayments as a function of river discharge and renewal with the open ocean. We are currently working on understanding how climate change will affect filter-feeder ecophysiology and the implications for climate change adaptation.
We have combined field observations and ecosystem modelling to investigate the effects of climate change on coastal ecosystems at the individual and ecosystem levels. Using long-term time series, we have demonstrated that the phenology of mussel larvae is changing, driven by the concomitant increase of ocean temperature in embayments of PEI. The influence of water temperature on the metabolism of poikilothermic organisms is critical for population dynamics, as we demonstrated for the non-indigenous bryozoan Membranipora membranacea. Although temperature is the main climate change driver, there are other drivers that can exert a significant effect on ecosystem functioning. For example, storms and hurricanes can alter coastal geomorphology and hydrodynamics, and consequently ecosystem functioning, as we demonstrated in an estuarine-scale experiment using field and modelling data pre- and post-storm. We have also used ecosystem modelling to forecast long-term climate change effects such as (1) the increase in mussel aquaculture production in St. Peter’s Bay driven by temperature and nutrient discharge via precipitation; (2) the competitive advantage of oysters vs mussels in a warming ocean due to different thermal tolerances; and (3) the differential resilience of coastal embayments as a function of river discharge and renewal with the open ocean. We are currently working on understanding how climate change will affect filter-feeder ecophysiology and the implications for climate change adaptation.
