Cold water corals with Heather Stewart - a people post from Carol Cotterill

Heather relaxes on the R/V Belgica before the
next core comes on deck
There are so many amazing people working at BGS that I thought we should have a regular “People Post” to introduce some of them to the outside world! I work at BGS Edinburgh, so will concentrate on Murchison House and Loanhead.....with over 150 people that should keep me going on a weekly basis for three years at least!
So onto my first “willing” people post guinea pig......Heather Stewart.

Heather works as a Marine Geoscientist and has been with BGS for 13 years. I asked Heather how she would describe her job – “Wonderful” came the reply. I think we need a little more digging here (excuse the pun) to describe what a Marine Geoscientist does.....!
Now I work as a Marine Geoscientist as well, and describe it to people as working with wet rocks – Heather was more descriptive (thankfully). Her work ranges from deep water environments to the surface of the seabed. This work covers so many areas including;
  • Biological Habitat Mapping – how do the sediments on the seabed vary, does this influence the biology that grows there, and are any aspects such as cold water corals endangered and need protecting;
  • Glacial Geomorphological Mapping – by mapping the features left behind by the last ice age, we can begin to understand how the ice sheets and glaciers that covered much of the UK grew and decayed, and what that meant in terms of a changing climate. It also helps us understand what once used to be land and how that affects the sediments left behind;
  • Distribution of the different sediment types on the seabed – since 1955, offshore extraction of aggregates (sands and gravel) have supplied >600 million tonnes to the UK construction industry. Aggregates have been used to combat coastal erosion by shoring up coastline defences and beach replenishment. Mapping of the sediments offshore also helps The Crown Estate manage mineral licensing and prospecting, benefitting the UK economy whilst protecting the flora and fauna unique to our waters.
Image showing backscatter (seabed roughness indicator) on the lefthand panel, the seabed sediment interpretation in the centre and a glacial geomorphology interpretation of a section of the backscatter in the righthand panel.
Mapping Mini-Mounds
Cold water coral reef habitat
(Image Crown Copyright 2006)
So onto a current project led by the Universiteit Gent investigating mini-mounds. Mini-mounds are colonies of cold water corals that grow up to 10’s of metres in width and up to 11 metres in height. Heather and colleagues are looking at three areas where mini-mounds are growing, or have grown, in the Bay of Biscay. So why are these coral growths important?

Sea-bed photograph of a mini-mound from the
South West Approaches (UK) showing coral rubble and
squat lobsters which are commonly found living
among the coral fragments

Cold water corals grow during interglacial periods – times of warmth when ice caps are smaller and vegetation changes on land. However, during glacial times when global temperatures drop and ice extends across much of northern Europe and Scandinavia, these coral communities stop growing, and become covered in layers of sediment. So if you go and investigate these coral mounds, you are effectively looking at large clocks that record climate change events like a living stopwatch.

Heather and  PhD candidate Tim Collart (UoG)
looking over a new core

Some of the questions they are attempting to answer using some cores collected from the Bay of Biscay earlier this year investigate the activity of these mounds in more detail, including why and how does their growth switch off, why do they sometimes die completely instead of going into “hibernation” and how do they start growing in the first place. It is hoped that the answers to these questions will tell us something about changes in ocean currents and environmental triggers that occur as the climate changes.

Heather then came up with a sentence that sums the work we do up so well;
You can find cool things in everything you do”.
And to put into context the epic task ahead of any of us working to understand our marine environment, the following facts are taken from an article published in Scientific American from October 2014: We have mapped the entire surface of the moon and 98% of the surface of Venus at 100m resolution, and 60% of Mars at 20m resolution. However our own oceans are only mapped at 5 km resolution.....we have a long way to go and a lot of cool things still to discover!
By Carol Cotterill