Foras na Mara

Deep water coral found in unexplored canyons off the South West continental shelf

Images Joint copyright (C) Defra, JNCC, Marine Institute, BGS

A team of Irish and UK Marine scientists discovered the cold water coral, Lophelia pertusa, in unexplored deep sea canyons 400km south of Cork on the edge of the European continental shelf during a recent MESH (Mapping European Seabed Habitats) survey on the Irish national RV Celtic Explorer.  Deep water camera equipment was used to capture images of the seafloor in water up to 1km deep, where pressure is 100 times greater than surface pressure. Cameras also captured evidence of the impact of fishing on the mound forming coral as trawl marks in the seabed and discarded fishing nets and ropes were encountered on a number of occasions.

The survey, carried out by the Marine Institute, the British Geological Survey (BGS), the University of Plymouth and led by the Joint Nature Conservation Committee (JNCC),  provided a test for using the INTERREG IIIB funded MESH project’s Guide to Marine Habitat Mapping for seabed surveys in deep offshore waters.

Little was known of the biology or geology of the canyons, on the cusp of UK, French and Irish territorial waters, beyond a few historical records of cold water corals.  One of the reasons for carrying out the survey was to find out if the canyons supported large cold water coral reefs, or steep rocky reefs, which could be considered for protection under the European Union’s Habitat Directive. 

The survey, between June 4th and 17th, centred over two canyons on the edge of the continental shelf plateau at 200m depth, down to 1,000m, covering an area greater than 850km2, more than 120,000 football pitches.  Scientists investigated the morphological and geophysical structure of the canyon systems and mapped the distribution and extent of the habitats using high resolution multibeam sonar to create 3D maps. The BGS’s sub bottom profiling sparker, capable of penetrating up to 500m below the canyon’s surface, was used on the R.V. Celtic Explorer for the first time, to examine the thickness of sediment layers and the structure of the underlying bedrock. 

“Some parts of canyons show erosional features and others depositional, with indications of both downward and upward currents across the survey area, resulting in the interesting geological structures and ecology of the area,” according to Heather Stewart of BGS.

 Forty-four video transects were made, lowering the camera on a winch wire to over 1000m deep and towing it along slowly, to distinguish biological communities in the canyons.  "Much more of the seabed than expected, consisted of fine, muddy sands," added Heather Stuart.  "We found hard substrata (rock and boulders) and corals in only a few areas along the steeper edges of the canyons".  Ripples in the sediment show current directions.  Sea cucumbers (Holothurians), squat lobster (Munida rugosa), numerous anemone and several starfish species, sea pens, shell debris and fish species were also encountered.

“In Ireland, techniques for marine habitat mapping have been developed within the Irish National Seabed Survey Programme and within INFOMAR - the successor project to map inshore waters” said Marine Institute Chief Executive Dr. Peter Heffernan speaking about the recent discoveries.  “The Marine Institute has been deeply involved with both of these projects, along with a number of partners including the Geological Survey of Ireland. Seabed habitat mapping is an important policy support tool in Sea Change – the Marine Knowledge and Information Strategy 2007 – 2013.”

Analysis of data will continue through to January 2008.  Maps showing the distribution of the different seabed habitats found will be produced, and cold water coral or rock reef habitats will be considered, where appropriate, for designation as Special Areas of Conservation under the EU Habitats Directive.  Findings are also being analysed as PhD research being undertaken at Plymouth University.

Ends

Notes to Editors

MESH - Mapping European Seabed Habitats  

MESH has been undertaken by an international consortium of 12 partners across the UK, Ireland, the Netherlands, Belgium and France and is funded under the EU INTERREG IIIB fund. It began in the spring of 2004 and is due to complete this year producing a range of ground-breaking maps and reports, including a web-delivered geographic information system (GIS) showing the habitat maps, templates for future marine mapping projects with protocols and standards, a report describing case histories of habitat mapping, and a stakeholder database. 

Many cutting-edge underwater survey techniques have been tested and reviewed by MESH for habitat mapping, including satellite remote sensing, aerial photography, high resolution acoustic echo sounders, deep sea video and remotely operated vehicles, divers and grab sampling.  Their findings show the best way to use techniques for habitat mapping, essential for protection of Special Areas of Conservation, and are a critical step towards an ecosystem approach to holistic resource management. 

One of the most exciting developments of MESH will be the delivery of the MESH Guide to habitat mapping, a web-based interactive multimedia tool  that will take the reader, be they an expert mapper or interested lay-person, through the processes and decisions required to design, carryout and interpret a marine survey.  The Guide will be launched in August 2007 and will be available on the  MESH website.  Tools and applications to assist with all the processes of habitat mapping will be available for free download.  This part of the MESH project is being coordinated through the Marine Institute and incorporates contributions from all the MESH partners. 
For further details visit the MESH website or contact Project Coordinator Jon Davies:jon [dot] davies [at] jncc [dot] gov [dot] uk

 

Sea Change

Provision of accurate marine habitat maps is vital information to the national Sea Change programme of marine research and development, which aims to drive the development of the marine sector as a dynamic element of Ireland’s knowledge economy. It uses a series of carefully calculated possible scenarios for Ireland by the year 2020 to define global market opportunities linked to the development of marine technologies and resources, as well as practical costed action plans and clearly defined objectives regarding how those opportunities might be achieved. Sea Change also highlights the need for a shift away from the traditional view of the sector as one primarily associated with the harvesting of food, and points towards a wide variety of market-led opportunities in sustainable energy, functional food products, transport, technology and environmental well-being. Mapping of our marine resources are an integral key to this.

The Marine Institute

The Marine Institute was created under the Marine Institute Act in 1991 to “undertake, to co-ordinate, to promote and to assist” in the development of marine research and development in Ireland. Since its early days in Harcourt Street Dublin, it has grown into an internationally respected science body with over 200 staff, two purpose-built vessels – RVCeltic Explorer and RV Celtic Voyager, a research facility near Newport, Co. Mayo and now a brand new headquarters and laboratory on the shores of Galway Bay.