Friday, 29 August 2014

Exploring the seaweeds of Europe’s largest artificial reef (Frithjof 29/08/2014)

Three diving marine scientists from the Hellenic Centre for Marine Research (HCMR) came to Scotland for a 10-day trip in order to explore the hitherto-unknown seaweed communities of the Loch Linnhe Artificial Reef in western Scotland (July 19-29). The project was hosted by the UK National Facility for Scientific Diving (NFSD), headed by Dr. Martin Sayer. Maria Salomidi, Kostas Tsiamis and Vasilis Gerakaris flew to Aberdeen, where they visited Frithjof at Oceanlab and in his home overlooking the Ythan Estuary. After one night there, they hit the long road from Aberdeen to the scenic West Highlands.

The Loch Linnhe Artificial Reef was built between 1998-2006, led by Martin Sayer and Tom Wilding at the Scottish Association for Marine Science, in cooperation with Foster Yeoman Ltd, operators of the Glensanda quarry in Morvern ( ). This large “superquarry” produces agglomeration for worldwide exports. This operation produces a fine powder as byproduct, which has no commercial value. In the late 1990s, this led to the idea of using it in a mixture with concrete for producing a type of breeze block-like elements which would be deployed in piles (termed “modules”) on the seabed of Loch Linnhe east of the Isle of Lismore. The rationale was that this would enhance structural diversity in a low-diversity soft-sediment area, resulting in locally increased biodiversity, standing stock of biota – in particular also of species of commercial interest. Even though the animal biodiversity and ecology, hydrology, biogeochemistry and other aspects of the reef had formed the centre of interest so far, no studies at all had considered the seaweeds of the reef.

The team managed to conduct a total of 25 diving operations, exploring the seaweed communities of the artificial reef from around 27 to 10 m depth and at natural reefs from 18 m to the surface. The wreck of the Breda, sunk in WW II by German bombers, was also surveyed – de facto it is an artificial reef which has been in the sea for over 70 years. The team was incredibly lucky with the weather: During the week of diving, the sea was flat calm and the sky mostly cloudless. Temperatures reached a record high ever recorded for Oban.

A total of around 50 seaweed species were recorded. It was also observed that on all except the modules > 20 m deep, seaweed standing stock exceeded animal standing stock by a large margin. Seaweed specimens were conserved on herbarium sheets; the communities on the reef were also amply documented by quadrat photographs.

We would like to thank Martin Sayer, Andy Mogg, Elaine Azzopardi and Hugh Brown at NFSD and the crew of the RV Seol Mara for their excellent support to the project which involved rather complex logistics and long working hours for everyone. Special thanks go to Martin and Jane Sayer for their legendary hospitality. The team would also like to acknowledge the EU program ASSEMBLE for funding this project.

A most memorable and worthwhile week in Oban!

 Andy Mogg readying underwater camera

 Grey seal at Eilean Dubh

 Laminaria hyperborea

 Soft corals on Loch Linnhe artificial reef

 Tritonia on a resupply mission

 Vasilis and Maria ready to dive

 Vasilis Maria and Frithjof on the Seol Mara

Vasilis Maria and Martin discussing on Seol Mara

No comments:

Post a Comment