On Friday 17^th July the DeepSeaCRU team from Plymouth University, working with partners from the National University of Ireland Galway, and the Centre for Environment, Fisheries and Aquaculture Science, will set out on the Irish Marine Institute’s research vessel Celtic Explorer, on a mission to test new maps of deep-sea sponge fields and cold water coral reefs of the North East Atlantic.

Celtic Explorer

Deep sea ecosystems are some of the most understudied and overlooked habitats in the natural world, and have extremely important roles as regions of biological diversity. As the pressures from global warming and human activity increase, it is becoming ever more important to understand these habitats so that they can be better protected and preserved. On this cruise we aim to further our understanding of these important and rare habitats by using computer models to predict the location of two main types of community, deep sea sponge fields and cold water coral reefs.

The sponge fields we are focusing on are dominated by the glass sponge Pheronema carpenteri. These sponges use silica (glass) to build their skeletons, and resemble fuzzy tennis balls on the seafloor (see our previous blog on this species).

A Pheronema carpenteri deep-sea sponge field in the Hatton-Rockall Basin, NE Atlantic. Image copyright © National Oceanography Centre, Southampton, UK 2011.

The cold water coral reefs we are focusing on are formed from the coral Lophelia pertusa. This species is similar to the corals associated with shallow water reefs but due to the absence of light in the deep, it does not have the symbiotic algae (Zooxanthellae) in its body tissues to help provide energy.

Cold water coral reef habitat

Both corals and sponges form the foundations of many ecosystems, offering food and protection to many other species. Not only this, but these habitats often act as nurseries for juvenile organisms such as commercial fish species further emphasising their importance. Both species are very vulnerable to disturbance and easily damaged by physical contact. By understanding where and why they live where they do we can begin to more effectively manage the deep sea to ensure the protection of these important but vulnerable ecosystems.

With the use of specially developed models it is possible to predict locations where the conditions found are suitable for these communities of animals to thrive. This is done by looking at the specific needs of an organism, such as the type of sediment that is needed to grow e.g. sandy or muddy or the optimum temperature, which is not too hot and not too cold. These preferences can then be looked at over a much larger scale to predict the likelihood that a community of that animal may be present. Using these methods we have created maps of the distribution of these habitats throughout the NE Atlantic.

Map of the predicted distribution of deep-sea sponge fields composed of Pheronema carpenteri in UK and Irish deep sea

On this expedition we will be visiting locations where we expect to find these communities based on high likelihood predictions from the models, and with the use of an underwater robot (remotely operated vehicle (ROV)) called Holland I, we will be able to survey the seabed and determine if the expected animals are found there.

Holland 1

Ultimately we hope to find new cold water coral reefs and new sponge fields, and to show that these types of predictive maps can give us useful information. The development and use of models, such as the ones we will be testing, will help to speed up efforts to conserve these habitats by providing information on where they are found at a fraction of the time and cost that is currently required.

This project is funded by the Eurofleets 2 programme.

text by Josh Davison.