Quantifying relationships between video observations of cold-water coral cover and seafloor features in Rockall Trough, west of Ireland

Abstract

Cold-water coral distributions are only partially understood even in the most wellstudied areas. This is partly due to the only recent development of appropriate technology, and partly to the high cost and time associated with coral mapping, particularly in deep water. One way to optimise mapping is to develop predictive habitat models as proxies for the actual distribution of corals. These models may provide objective criteria for the selection of prioritised coral mapping areas. In this study, we quantified the relationship between observed cold-water coral distribution and terrain attributes as an important step in developing predictive habitat models. We estimated deep-water coral percentage cover from remotely operated vehicle video and demonstrate how such data can be used to examine quantitative relations between coral cover and terrain parameters (slope, aspect, rugosity and bathymetric position index) derived from ship-borne multibeam swath acoustic data. We show that, at carbonate mound provinces within sites on the Irish margin, coral abundance is correlated with terrain that is strongly sloping and irregular to a varying degree, depending on spatial scale. It is likely that terrain variations influence the hydrodynamic setting, resulting in a varying food supply. A similar approach may be applicable for other fauna in a variety of benthic environments. KEY WORDS: Habitat mapping · Terrain analysis · Remotely operated vehicle · Carbonate moundsResale or republication not permitted without written consent of the publisher OPEN PEN

Diversity, distribution and spatial structure of the cold-water coral fauna of the Azores (NE Atlantic)

“…These findings are in line with the known habitat requirements for most coral species, namely the presence of hard substrates with high topographic relief (Genin et al, 1986;Mortensen and Buhl-Mortensen, 2004;Guinan et al, 2009;Tong et al, 2012), low levels of sedimentation (Roberts et al, 2006), enhanced current flow (Frederiksen et al, 1992;Mienis et al, 2007;Dorschel et al, 2007) and high food supply (Bryan and Metaxas, 2007;Davies et al, 2009). …”

“…Widely distributed throughout the world's oceans, they can be found on continental shelves and margins, edges and slopes of oceanic islands, seamounts, canyons and ridges (e.g. Cairns, 2007;Wareham and Edinger, 2007;Molodtsova et al, 2008;Mortensen et al, 2008;Reveillaud et al, 2008;Baker et al, 2012), especially in areas of high currents and/or enhanced suspended or re-suspended organic matter (Davies et al, 2009;Guinan et al, 2009).…”

In-situ observation of deep water corals in the northern Red Sea waters of Saudi Arabia

“…DWCs are usually occur in areas of pronounced topographic relief and their distribution and abundance are influenced by environmental factors such as temperature, water current and substrate type (Mortensen and Buhl-Mortensen, 2004;Buhl-Mortensen et al, 2010;Guinan et al, 2009;Yesson et al, 2012;Bryan and Metaxas, 2006;Tong et al, 2012;Rengstorf et al, 2013). In our study, the maximum abundance and diversity of DWC was recorded from an area (A1) that is located relatively near the shore (Fig.…”

“…Among the 723 azooxanthellate scleractinian coral species currently known, the majority (532 species, 73.6%) are solitary in habit while the remainder (191,26.4%) are colonial. The distribution of DWC is governed by various factors including temperature and calcium carbonate saturation (Cairns, 2007), topographic relief (Mortensen and Buhl-Mortensen, 2004;Buhl-Mortensen et al, 2010;Guinan et al, 2009;Yesson et al, 2012), sedimentary regime and currents (Thiem et al, 2006;Bryan and Metaxas, 2006;Wilson et al, 2007;Dolan et al, 2008).…”

The impact of modelling method selection on predicted extent and distribution of deep-sea benthic assemblages

“…Slope provides terrain gradient in degrees and serves as a proxy for the local hydrodynamic regime (Guinan et al 2009). Rugosity acts as a measure of terrain 'roughness', or structural complexity, and also serves as a surrogate for substrate type (Rinehart et al 2004;Dunn & Halpin 2009).…”