Cold-Water Corals. Distribution of fauna and responses to environmental perturbation

  • Over the last decade, the importance of Cold-Water Coral (CWC) reefs as hotspots of elevated biodiversity on the European continental margin has become firmly established in scientific literature. Reefs are formed predominantly by the calcium carbonate skeletons of successive generations of Scleractinian corals such as Lophelia pertusa (Linnaeus, 1758). This skeletal structure often forms complex 3D structures which can provide a host of habitat niches for other fauna. Advances in remote sensing techniques has led to the location of a large number of reef structures, commonly in regions with elevated flow or productivity, such as on the Norwegian margin. Often these reefs are associated with high commercial fish stocks, and structural damage to reef ecosystems from fishing activity has led to progressively more CWC reefs being closed to fishing by various national legislations. The oil and gas industry also operates in regions and at depths where extensive reef structures can are found, and there is a level of concern over the potential negative impact this industry may have on these ecosystems. The variation in faunal composition across and between reefs has only been investigated in a few studies to date. Likewise, the fundamental functioning of some of the key ecosystem species, such as Lophelia pertusa, is not well understood. In this thesis a selection of techniques were used to fill some of these knowledge gaps. A novel method was developed utilising machine-learning algorithms to swiftly and semiautomatically quantify percentage coverage of substrate by living coral polyps. The system was used to assess live coral coverage across a trawl damaged region of the Tisler reef, Norway. The machine-learning algorithm method performed as accurately as a human in quantifying coverage (using standard methodologies), but in considerably less time. Distribution of a selection of fauna across and between Norwegian reefs was investigated using a large dataset collected as part of the Hotspot Research on the Margin of European Seas (HERMES) project. Previously unreported distribution patterns were observed on a variety of spatial scales for a number of the species investigated. Laboratory work was conducted to determine the degree to which flow velocity related to net zooplankton capture rates by Lophelia pertusa. The investigation clearly indicated that a significantly higher capture rate was attainable under 0.025 m s-1 than 0.05 m s-1 flow velocity, a surprising result given the high flow velocities often prevalent at reef locations. Additional laboratory investigations subjecting Lophelia pertusa polyps to doses of various anthropogenic materials (waste from drilling operations, trawl resuspended sediments) were conducted, with results indicating a general resilience of the species to particle exposure.

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Publishing Institution:IRC-Library, Information Resource Center der Jacobs University Bremen
Granting Institution:Jacobs Univ.
Author:Autun Purser
Referee:Laurenz Thomsen, Jelle Bijma, Vikram Unnithan, Andres R├╝ggeberg
Advisor:Laurenz Thomsen
Persistent Identifier (URN):urn:nbn:de:101:1-2013052411290
Document Type:PhD Thesis
Date of Successful Oral Defense:2010/05/10
Date of First Publication:2010/05/19
PhD Degree:Geosciences
School:SES School of Engineering and Science
Other Countries Involved:Belgium
Library of Congress Classification:Q Science / QH Natural history - Biology / QH301-705.5 Biology (General) / QH324 Methods of research. Technique. Experimental biology / QH324.2 Data processing. Bioinformatics
Call No:Thesis 2010/8

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