Declan joined this Science Foundation of Ireland Survey for Training Through Research Surveys at the invitation of Scientist in Charge Dr Louise Allcock of NUI Galway on the RV Celtic Explorer.
Deep-sea Exploration: Into the Unknown
My name is Declan Morrissey. I am a recent graduate from
Marine Science in NUIG. Currently, I am aboard the RV Celtic Explorer participating in a deep-sea ROV cruise as part
of the Strategic Marine Alliance for Research and Training (SMART) Trainingthrough Research Surveys (TTRS) programme.
The purpose of this cruise is biodiscovery - that is to find novel
natural compounds that may have the potential to be used in the treatment of
disease and illnesses. The expedition is a part of a 5 year project
"Exploiting and conserving deep-sea genetic resources” funded by Science
Foundation Ireland and the Marine Institute.
This cruise requires the use of Ireland’s ROV Holland I. This ROV has a depth rating
of 3000 m. This amazing piece of equipment allows us to peak into the secretive
world of the deep sea. Here, we have colonies of Lophelia pertusa, a dominant reef-building coral of the North-East
Atlantic. This coral provides an elevated position and hard substrate for other
fauna to attach. This is highly advantageous for filter feeders. Corals can
also attach to steep surfaces of seamounts and canyon walls where Lophelia reefs are either absent or do
not provide enough surface area for all the life. It is estimated that
worldwide cold-water corals have the same abundance and distribution as their
shallow water counterparts (284,000km2) and the same associated
biodiversity.
Figure 1. Lophelia pertusa
reefs at the Hovland Mounds. Note that the large amounts of dead reef are GOOD.
The live coral grows on top of the dead skeleton framework so it means this
reef has been thriving for thousands of years.
This cruise was lucky to have permission to explore
both the Hovland Mounds Special Area of Conservation (SAC) and the Belgica MoundsSAC, the purpose being to record footage of the fauna and determine the habitat
heath. It will also feed into future predictive habitat modelling which will
give us a better idea of the most probable areas these animals can be found. It
does this by forming a relationship between the living organism and the associated
environmental variables, such as slope, current speed, etc. Due to the deep
sea’s large size and how expensive it is to survey, these models provide a good
baseline for planning future biodiscovery projects and for informing
conservation policy for the promotion of areas to a protected status. This is
an area I am pursuing later in the year at ICBM in the University of Oldenburg,
Germany. It is an incredible experience to see these habitats first hand. Areas
of interest during this survey include submarine canyons. Submarine canyons are
thought to be biodiversity hotspots due to the funnelling of nutrients from the
shallow productive environment to the deep sea. The incised walls of the canyon
provide steep surfaces for the attachment of corals and sponges, which are of
particular interest. I am looking
forward to returning to the Whittard Canyon as last year I gathered sediment
cores from the Whittard Canyon to hunt for microplastics.
Figure 2. A murder of
venus fly trap anemones (Phelliactis sp.) gathered around the only hard
substrate in the area. Referred to as a murder by our chief scientist Dr.
Louise Allcock for their voracious appetite.
My role here is to assist all the senior scientists in any
way and learn as much as possible. With three chemists ( Dr. Ryan Young, Prof.
Olivier Thomas, and Robert Nesbitt), four zoologists (Dr. Louise Allcock our
chief scientist, Dr. Claire Laguionie-Marchais, Raissa Hogan, and Morag Taite),
and one oceanographer (Eoghan Daly) on board
I have been learning a lot about the deep sea and the animals that inhabit this
highly understudied ecosystem.
Figure 3. Decorator crab
holding a Paramuricea octocoral. We
can still see you!
One of the more intense places onboard is Holland I’s
control shack. Here, two pilots and up to three scientists control the ROV.
Here one taxonomist and one chemist guide the pilot's route depending on what
is interesting. Luckily, there is room for a student as well so I have been
aiding with this process. In the shack, time has no meaning. Hours feel like
minutes as you are so engrossed in the visuals of the deep-sea ecosystem that
anything happening outside that room becomes irrelevant.
Corals and sponges are known to have an interesting
chemistry, according to the on-board chemists Ryan, Olivier, and Robert. For
this reason, we are collecting samples belonging to these phyla. Any sample
that is collected will have genetic and taxonomic work carried out back on
shore with the remainder examined for novel compounds. These compounds will
hopefully end up in medicines in the future. Bycatch is also not wasted and is
quickly preserved for future genetic work. Genetic work is very important to
understand the evolution and relationships of these animals and it can identify
key features in their past such as population declines or bottlenecks.
Eoghan Daly, a postgraduate student interested in the
effects of trawling on seabed rugosity, is using the multibeam onboard.
Rugosity is the measure of the roughness of the sediment. Certain corals and
sponges have a preference on which type of sediment they grow in so any
man-made changes in this composition has wider biodiversity impacts.
Figure 4. Transparent sea
cucumbers (Holothurians). As deposit feeders they eat the sediment to extract
carbon and nutrients which is passed through their gut…as you can see.
Of course, I have been involved with data logging. Data
logging with large amounts of information can become very tricky very fast if
not kept on top of. One thing about the ROV is that it’s data heavy. We get positional data (lat, long, depth)
every 10 seconds or so from the USBL system, each 2hr high def video is about
100 Gb, we get video feeds from 3 other cameras, and also have a series of
still digital images to process. This is
on top of the data associated with the samples that we collect. Everything
needs to be accounted for. A properly
managed data set is the first step to a successful project. This cruise has
multiple outcomes and these all use different aspects of the gathered data.
All the skills I learn on board are of great value as I hope
to pursue deep-sea research at the University of the Algarve as part of my M.Sc.
this September. In particular, I would like to compare biodiversity trends and
physical processes in the Whittard Canyon off the wide Irish shelf with that of
the Lisbon and Nazaré Canyons which are located near urban bases off the narrow
Portuguese shelf.
By Declan Morrissey
Acknowledgements
I would like to thank Dr Louise Allcock and her excellent crew of scientists for sharing their knowledge and extending the invitation to join them in a fantastic voyage of discovery.
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