Submarine Structures in the Mid-Irish Sea and Solan Bank
(2008)
The survey carried out on behalf of JNCC by Cefas had two
objectives:
- To map the extent and condition of an area of potential
Methane Derived Authigenic Carbonate which has
formed reef-like structures in the mid-Irish Sea;
- To map the extent and condition of bedrock and stony
reef around Solan Bank off the north-west coast of
Scotland.
Submarine Structures in the mid-Irish Sea
Survey work within the "Submarine structures in the mid-Irish
Sea" Area of Search took advantage of previous work undertaken by
the SEA6 surveys commissioned by the Department of Trade and
Industry, and gathered additional high resolution acoustic data.
High quality underwater imagery (video and still images) were also
obtained, along with seabed samples, to help interpret the acoustic
data.
"Submarine structures made by leaking
gases" are an Annex I habitat under the
EC Habitats
Directive. These seabed structures are often formed from
Methane Derived Authigenic Carbonate, or MDAC. MDAC occurs where
seabed sediments become bound together by carbonate cement - a
bi-product of the microbial oxidation of methane rising up through
the seabed, forming reef-like structures that provide a unique
habitat for a wide range of marine life.
Solan Bank
The Solan Bank Area of Search was found to have extensive
areas of bedrock outcrops with high topography, with linear cliffs
rising up to 10 metres from the surrounding seabed running in
ENE-WSW and SE-NW orientations. Away from the cliffs the substrata
ranged from well sorted sands through to highly fissured bedrock
reefs. The majority of reef sites were characterised by encrusting
fauna, in particular encrusting bryozoans and
encrusting corallines in shallower waters. Species
of note were an unidentified cup coral, a
sponge which has only previously been recorded
from fishing trawl records and not seen in situ before
(Oceanapia robusta) and another species
of sponge classified as rare (Poecillastra
compressa).
Further Reading
- Submarine structures in
the mid-Irish Sea leaflet
- Whomersley, P., Wilson, C., Clements, A., Brown, C., Long, D.,
Leslie, A., Limpenny, D. 2009. Understanding the marine environment
- seabed habitat investigations of Submarine Structures in the
mid-Irish Sea and Solan Bank Area of Search (AoS). JNCC Report
430.
Project Contractors
If you have any further questions about JNCC's offshore survey
work then please contact us.