Quantifying the distinctiveness of deep-water vertical habitats

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To support marine spatial management, we need to understand better the spatial distribution of ecologically important habitats, which can be facilitated by identifying the factors that play significant roles in shaping biological spatial patterns. The main issue in deeper waters is that most habitats are poorly studied, with rarer ones still being discovered. In shallow coastal waters, the slope of the seabed has long been identified as an important structural component for benthic communities, with differences in composition observed between vertical and flat areas. In deeper waters, however, traditional sampling equipment are ineffective in rugged environments. Deep vertical habitats have therefore not been studied in detail, even though large vertical reefs of overhanging scleractinians, and walls inhabited by alcyonacea, bivalves and sponges are increasingly being discovered, and likely represent an underestimated high biodiversity habitat. Because of their complex topography, cliff environments provide natural protection to vulnerable species against trawling activities, potentially allowing larvae to recolonize surrounding damaged habitats. However, not all walls are necessarily biodiversity hotspots, and it remains unknown whether they host assemblages different from nearby flat terrain. That said, we can hypothesize that environmental conditions likely affect vertical habitats distinctly. For example, large coral colonies may only grow on rock faces with particular strength properties and currents likely interact with the steep topography to create complex flow patterns that affect suitability of feeding conditions, potentially controlling fine-scale spatial patterns. The aim of this research program is to understand the role of deep-water vertical habitats in controlling local and regional spatial biodiversity patterns. Beta-diversity comparisons between vertical-wall and flat-terrain communities will be performed, and the geological, hydrodynamic and biological controls on habitat complexity, diversity and fine-scale niche selection of associated fauna will be investigated. This work will make use of existing video datasets, as well as collect new datasets from deep-water fjords in Newfoundland and upcoming offshore expeditions. Understanding the factors controlling the distribution of these biodiversity hotspots is crucial to the implementation of successful conservation measures given global declines in marine biodiversity. Now that Canada has met its 2020 conservation targets, monitoring of biologically and ecologically significant habitats will be key to ensure early detection of change. By investigating geological, hydrodynamic and biological controls, this project will increase our understanding of the factors that control the biodiversity and distribution of understudied deep-water vertical habitats.