Soft coral garden discovered in Greenland's deep sea

Date:
June 29, 2020
Source:
University College London
Summary:
A deep-sea soft coral garden habitat has been discovered in
Greenlandic waters using an innovative and low-cost deep-sea video
camera built and deployed by the team.



FULL STORY ==========================================================================
A deep-sea soft coral garden habitat has been discovered in Greenlandic
waters by scientists from UCL, ZSL and Greenland Institute of Natural Resources, using an innovative and low-cost deep-sea video camera built
and deployed by the team.


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The soft coral garden, presented in a new Frontiers in Marine Science
paper, is the first habitat of this kind to have been identified and
assessed in west Greenland waters.

The study has direct implications for the management of economically
important deep-sea trawl fisheries, which are immediately adjacent to
the habitat. The researchers hope that a 486 km2 area will be recognised
as a 'Vulnerable Marine Ecosystem' under UN guidelines, to ensure that
it is protected.

PhD researcher Stephen Long (UCL Geography and ZSL (Zoological Society London)), first author on the study, said: "The deep sea is often
over-looked in terms of exploration. In fact we have better maps of the
surface of Mars, than we do of the deep sea.

"The development of a low-cost tool that can withstand deep-sea
environments opens up new possibilities for our understanding and
management of marine ecosystems. We'll be working with the Greenland
government and fishing industry to ensure this fragile, complex and
beautiful habitat is protected." The soft coral garden discovered by the
team exists in near total darkness, 500m below the surface at a pressure
50 times greater than at sea-level. This delicate and diverse habitat
features abundant cauliflower corals as well as feather stars, sponges, anemones, brittle stars, hydrozoans bryozoans and other organisms.



==========================================================================
Dr Chris Yesson (ZSL), last author on the study, said "Coral gardens
are characterised by collections of one or more species (typically
of non-reef forming coral), that sit on a wide range of hard and
soft bottom habitats, from rock to sand, and support a diversity of
fauna. There is considerable diversity among coral garden communities,
which have previously been observed in areas such as northwest and
southeast Iceland." The discovery is particularly significant given
that the deep sea is the most poorly known habitat on earth, despite
being the biggest and covering 65% of the planet. Until very recently,
very little was known about Greenland's deep- sea habitats, their nature, distribution and how they are impacted by human activities.

Surveying the deep sea has typically proved difficult and expensive. One
major factor is that ocean pressure increases by one atmosphere (which
is the average atmospheric pressure at sea level) every 10 metres of
descent. Deep-sea surveys therefore have often only been possible using expensive remote operating vehicles and manned submersibles, like those
seen in Blue Planet, which can withstand deep-sea pressure.

The UK-Greenland research team overcame this challenge by developing a
low-cost towed video sled, which uses a GoPro video camera, lights and
lasers in special pressure housings, mounted on a steel frame.

The lasers, which were used to add a sense of scale to the imagery, were
made by combining high-powered laser pointers with DIY housings made at
UCL's Institute of Making, with help from UCL Mechanical Engineering.



==========================================================================
The team placed the video sledge -- which is about the size of a Mini
Cooper - - on the seafloor for roughly 15 minutes at a time and across
18 different stations. Stills were taken from the video footage, with
1,239 images extracted for further analysis.

A total of 44,035 annotations of the selected fauna were made. The
most abundant were anemones (15,531) and cauliflower corals (11,633),
with cauliflower corals observed at a maximum density of 9.36 corals
per square metre.

Long said: "A towed video sled is not unique. However, our research is certainly the first example of a low-cost DIY video sled led being used
to explore deep-sea habitats in Greenland's 2.2million km^2 of sea. So
far, the team has managed to reach an impressive depth of 1,500m. It
has worked remarkably well and led to interest from researchers in
other parts of the world." Dr Yesson added: "Given that the ocean is
the biggest habitat on earth and the one about which we know the least,
we think it is critically important to develop cheap, accessible research tools. These tools can then be used to explore, describe and crucially
inform management of these deep-sea resources." Dr Martin Blicher
(Greenland Institute of Natural Resources) said: "Greenland's seafloor is virtually unexplored, although we know is it inhabited by more than 2000 different species together contributing to complex and diverse habitats,
and to the functioning of the marine ecosystem. Despite knowing so little
about these seafloor habitats, the Greenlandic economy depends on a
small number of fisheries which trawl the seabed. We hope that studies
like this will increase our understanding of ecological relationships,
and contribute to sustainable fisheries management."

========================================================================== Story Source: Materials provided by University_College_London. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Stephen Long, Bridget Sparrow-Scinocca, Martin E. Blicher, Nanette
Hammeken Arboe, Mona Fuhrmann, Kirsty M. Kemp, Rasmus Nygaard,
Karl Zinglersen and Chris Yesson. Identification of a Soft Coral
Garden Candidate Vulnerable Marine Ecosystem (VME) Using Video
Imagery, Davis Strait, West Greenland. Front. Mar. Sci, 2020 DOI:
10.3389/ fmars.2020.00460 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200629090014.htm

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