Cold-water coral distributions and surficial geology on the Flemish Cap, Northwest Atlantic

Miles, Lara Lynne (2018) Cold-water coral distributions and surficial geology on the Flemish Cap, Northwest Atlantic. Masters thesis, Memorial University of Newfoundland.

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Abstract

This thesis investigates possible geological preferences of cold-water coral species over varying spatial scales. Cold-water species and surficial geology were identified from geo-referenced video imagery covering 15.09 km of seabed, at four sites on the flanks of the Flemish Cap in the Northwestern Atlantic. Species distribution and abundance were compared to the surficial geology and lithology described at five spatial scales. A total of 30,310 individual corals were enumerated comprising 27 species on 8 different geological facies. Hard substrate inhabiting species did not show a preference for attachment substrate grain size or lithology type. The most abundant species Anthomastus spp. (soft coral) was the only species found on all grain sizes and both lithology types. Surficial geological facies were statistically distinct when described at finer spatial scales (10 m, 50 m, 100 m) but, not at broader scales (500 m and 1000 m). Species distributions were primarily driven by depth and secondarily by substrate type. While other environmental variables described at coarse spatial scales (thousands of km) are suitable for predicting cold-water coral distributions; surficial geology is a more suitable surrogate at finer spatial scales. These observations highlight the importance of describing substrate and surficial geology at spatial scales less than 100 m.

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