Reproduction and dispersal strategies in extreme environments: insights into persistence and shifts in marine biodiversity

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The long-term objective of my research program is to clarify the drivers and adaptive significance of breeding and dispersal strategies in cold-water and deep-sea benthic animals, in the context of a changing ocean. Life-history events are explored from the perspectives of chronobiology (relation between biological activity and time), phenology (relation between periodic events and climatic conditions) and evolutionary biology (adaptive benefits of life-history strategies). We recently demonstrated lunar mass-spawning events in 24 boreal species belonging to 6 phyla, as well as seasonal and lunar breeding cycles in deep-sea species exposed to weak environmental variability. We also assessed the underpinnings and significance of lecithotrophy/oviparity (maternally provisioned propagules) on the continuum between planktotrophy (externally feeding propagules) and matrotrophy/viviparity (live bearing). Currently proposed advantages of rhythmic reproductive events cannot fully explain why so many species release progeny in sync, irrespective of reproductive strategies, depth or region. Moreover, historical predictions made about gradients of non-pelagic development and pelagic lecithotrophy towards the deep sea and the poles (e.g. Thorson's rule) have been both supported and challenged, calling for further study of the selective pressures at play. Extending my research program into the Arctic for this funding cycle follows a twofold premise. (1) It complements our studies along subarctic coasts and in the deep sea (representing marked and weakly seasonal environments, respectively), and allows us to test hypotheses related to photoperiod (high latitude, seasonal ice cover) and food availability (unique primary production) using the same or closely related taxa. (2) Marine species are expected to shift their distributions towards the Arctic in the face of climate change, while pressures on this environment (ocean warming, shipping and mining activities) increase, stressing the need to understand local life-history strategies to predict impacts on biodiversity. The short-term objectives are to identify (i) intra and interspecific spatial dynamics related to reproductive strategies; (ii) sources and cycles of energy storage and reproductive investment; and (iii) drivers of breeding periodicities in Arctic benthic taxa (echinoderms, cnidarians, mollusks). Identifying drivers of breeding and dispersal strategies in Arctic marine taxa will provide insight into shifting biodiversity and distribution patterns, and assist management strategies supporting food security in Canada's northernmost communities. The interdisciplinary context of the proposed program provides opportunities for significant discoveries and for training HQPs (including Indigenous scientists) in a variety of tools and techniques inside a collaborative environment.