News from the seabed…
Dr Anuschka Miller (SAMS) & André Cocuccio (MCA)
Since January 2011, a European Union funded project has been surveying areas including Dundrum Bay and SE Mourne Coast, Carlingford Lough and Approaches and Dundalk Bay, to gather information on the depth, shape and sediment type of the seabed. The project is also responsible for gathering data off the west coast of Scotland.
Multibeam echosounder image of newly discovered 113m long and 1.3m high shipwreck lying in Dundalk Bay at a minimum depth of 17.9m. Image courtest of Chris Martin, Marine Institute
With first results beginning to emerge, a previously unknown shipwreck has just been discovered in Dundalk Bay. So far, researchers have been unable to find any records relating to the wreck, which appears to lie upside down. Comprising a bulky rectangular object with a flat top surface and a long mast-like structure protruding from it, the wreck looks like a giant spade sitting on the seabed.
Why we need seabed information
Whilst modern terrestrial maps are largely highly accurate, seabed maps are often much less so, with some of the data used to construct them originating from 19th century lead-line measurements.
Nowadays, state-of-the-art survey vessels employ high-resolution multibeam echosounder (MBES) technology to record seabed information in detail. This works by simultaneously emitting hundreds of sound beams beneath the survey vessel, whilst onboard computers ‘listen’ for and record the return echoes or ‘soundings’ to be reflected back from the seabed, or a wreck sitting on it.
As the survey vessel continues along its pre-defined survey line-plan, the MBES system compiles and stores all the soundings it receives, building up a picture of the seabed as it goes. Once completed, the compiled soundings or ‘bathymetry’ can be used to produce a highly detailed, three-dimensional model of the seafloor and any objects located on it.
Many people benefit from this kind of information: in particular the data are used to improve nautical charts and provide environmental planners and developers with an accurate picture of the types of seabed habitats around our coast. Furthermore, reliable maps of the seabed are a prerequisite for safe shipping and for the effective management and conservation of the marine environment.
This kind of high-resolution data may also help the authorities to identify both appropriate sites for developing marine renewables and areas that may deserve particular protection measures.
THE INIS Hydro Project
The INIS Hydro project, which receives £3.2m from the European Union’s INTERREG IVA Programme, brings together seven partner organisations from the Republic of Ireland and the UK to generate high-resolution bathymetric datasets for over 1400 km2 of key coastal seabed areas off the coasts of Ireland, Northern Ireland and Scotland to the most rigorous of international standards (IHO Order 1a).
The project fosters close working relationships between the partner organisations through the development and implementation of a standardised seabed survey specification, as well as the sharing of good practice between the partners.
INIS Hydro is led by the Maritime and Coastguard Agency and delivered by the Agri-Food and Biosciences Institute, the Geological Survey of Ireland, the Marine Institute, the Northern Lighthouse Board and the Scottish Association for Marine Science. The UK Hydrographic Office is the seventh partner providing quality assurance of the acquired data.
On completion of the project by September 2013, all data will be made freely available to the public.
For more information visit www.inis-hydro.eu
