Megabenthic biotope composition of the Rockall Escarpment, Northeast Atlantic

Nickson, Ashley (2023) Megabenthic biotope composition of the Rockall Escarpment, Northeast Atlantic. Memorial University of Newfoundland. (Unpublished)

[English] PDF (Undergraduate Honours Thesis) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (1MB)

Abstract

The depths of the ocean have been largely shrouded in the unknown. However, technological advances made in the past 60 years have provided researchers with the opportunity to start unravelling the complexities of the deep sea. There is now an understanding that the deep sea is host to a complex and diverse mosaic of communities that we also realize are in peril due to the effects of climate change. This thesis examined the biodiversity patterns and biotope composition present within the Rockall Escarpment, situated in the Northeast Atlantic Ocean. We used data that was annotated from images across nine transects, totalling to 16,150 m, obtained by a Remotely Operated Vehicle. Benthic community composition was assessed across the whole study area using Non-Metric Multidimensional Scaling (nMDS), followed by SIMPER, and indicator species analysis to classify the benthic taxa observed into biotopes. In total, 59,418 individual organisms representing 199 megafaunal morphospecies were analyzed. Twelve biotopes were identified, biotopes five, six, nine, and twelve composed of vulnerable sessile taxa including the cold-water corals Solenosmilia variabilis, Madrepora oculata, and Desmophyllum pertusum. Substrate, food availability and currents are among the most significant factors influencing the complex geomorphology and consequently, the distribution of megafaunal species. Determining the megafaunal species richness and abundance present, and the factors that affect their distribution, provide insights into vulnerable biotopes. Understanding the vulnerable biotopes present will ultimately contribute to our baseline knowledge of the distribution of taxa in the Northeast Atlantic and hopefully, management measures that are climate adaptive.

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