At over 1500 m tall, Anton Dohrn Seamount is one of the UK’s highest mountains (taller than Ben Nevis, Snowdon and Scafell Pike!), yet its summit lies 600 m below sea level in the North East Atlantic! The steep-sided seamount sits in over 2000 m of water and is located 200 km to the west of Scotland in the Rockall Trough, a deep water channel in the North East Atlantic.
The seamount is about 45 km wide and is a former volcano that was last active around 40-70 million years ago. Its summit has since been eroded by waves to give the seamount a flat, fairly uniform top. Steep slopes extend down the side of the seamount to a moat at around 2400 m deep. This short video shows you just what the seamount looks like underwater:
The Seamount was named after the German research vessel that discovered it in the late 1950s, which in turn was named after a prominent German biologist, Anton Dohrn, who was the founder and director of the first zoological research station in the world.
The seamount is home to a wide range of animals, including the orange roughy (also known as the slimehead!), which can live for up to 149 years!!! These are predatory fish that live on or just near the seafloor close to strong currents that bring their food (other fishes and squid) to them (http://oceana.org/marine-life/ocean-fishes/orange-roughy).
The seamount also has some of the funkiest reefs we’ve seen in the area (and super deep too, over 1200 m!). These cold-water reefs are full of stony corals, sea fans (gorgonians), and giant black corals, which could be hundreds or even thousands of years old!! A species of black coral found at around 500 m deep in Hawaii is thought to live for over 4000 years (http://www.cbsnews.com/news/black-coral-can-live-for-over-4000-years-leiopathes-annosa/). While that coral species doesn’t live on Anton Dohrn Seamount, we do have something similar, which could live for just as long!
Because of the high number of species found on the seamount, the amazing coral gardens, and the slow growth rate of many species, the cliff edges and sides of the seamount are now protected within a Marine Protected Area (MPA), which limits the damaging activities that can take place around the seamount (http://jncc.defra.gov.uk/page-6527).
Large areas of the seamount are still unexplored because of the difficulty in surveying areas that are so deep. During this trip, we will be using the ISIS Remotely Operated Vehicle (ROV) on board the RRS James Cook to record high-definition video of the animals living on the top of the seamount and on the north-west facing slope. We will also use the ROV to collect samples of these animals for identification and genetics analysis when we get back to dry land.
More details of what we find and how we process the samples we collect will be shared in future blogs over the next 5 weeks. Stay tuned!
Text by Nicola Foster and Rebecca Ross, Plymouth University