Ocean study could lead to protections for world’s seabed
An ambitious global study of the ocean seabed’s contribution to climate change mitigation through carbon capture has made its way to Bermuda, the source of the project’s $15 million budget.
The five-year Convex Seascape Survey has enlisted a team of more than 100 scientists who have been visiting locations around the world collecting sediment from the sea floor for analysis.
Its research could provide crucial data, lacking at present, to make a case for restrictions around destructive fishing practices such as bottom trawling and other human activities that kick up the sediment resulting in the carbon being released back into the atmosphere contributing to climate change.
The Convex team said as such, there is an “urgent” need to collaborate and build scientific consensus that leads to informed policies regarding sediment habitats.
Unlike seagrass, salt marsh and mangroves, marine sediment is not recognised by global policy frameworks as a habitat for blue carbon — organic carbon captured and stored by the ocean.
The Convex survey studies the importance of the ocean in the global carbon cycle, the historical impact and spread of human influences on the seabed, and the role of life and biodiversity on seascape carbon stores.
Backed by Bermudian-headquartered speciality reinsurer Convex Group, founded by Stephen Catlin, the science is being led by one of the world’s leading marine scientists, Callum Roberts, Professor of Marine Conservation in the Centre for Ecology and Conservation at the University of Exeter, in England.
The Royal Gazette was invited to spend a morning on the water with some of the scientists who were in Bermuda including Ben Harris, the postdoctoral research fellow for the project.
Dr Harris, who identified locations appropriate for the project criteria and created sampling methodologies, explained that the study is focused on areas within the world’s continental shelves which accumulate mud containing organic carbon.
These relatively shallow areas, which extend to about 200 miles off shore, are most affected by human activity, not least bottom trawling — an industrial fishing method that scrapes up the sea floor.
“We have been interested in these areas as they accumulate a lot of mud that has a lot of organic carbon content,” Dr Harris explained.
“Over time as it settles into the seabed, it gets stored. That is essentially a way of sequestering carbon from the atmosphere into the seabed.
“The trouble is, when we come through with building infrastructure or bottom trawls, it kicks it back into the water column and, through a microbial process, that organic carbon can get released into the atmosphere.
“The challenge right now is climate change and a lot of that is driven by rising Co2 levels.”
Dr Harris said the continental shelf covers about 27 million square kilometres, equal to about 7 per cent of the surface area of the oceans. The study seeks to discover how much carbon is there, how long has it been there and what the historical impact of humans is on that store.
He added: “We are looking at areas that are heavily impacted by trawling but also areas that have been protected for some time so we can compare and contrast.
“I’m also interested in the ecology — when you come in with a trawler, you rip all the stuff that is living in the seabed. What role does that play in this cycle? If you destroy the ecology, will that have an impact on the carbon as well?
“We think the organisms are also contributing to the carbon burial.”
The project collects samples in plastic cores showing the organic carbon make up, in some cases over millennia.
Study locations span from the tropics to the poles including Scotland and Jersey, Canada, New Zealand, Australia, Patagonia, South Africa and the Antarctic.
While these locations are on the continental shelf, Bermuda is the exception as an oceanic environment.
Dr Harris explained: “We wanted to have one site to compare and contrast all that continental muddy environment; a different place to have that reference point.”
Dr Roberts said that most fishing catch — about 95 per cent — comes from shallow coastal seas and that nearly all seabed disturbance is in those shallow seas.
“Some of the carbon gets sequestered in the sediment and there it should stay, and would if it were not for people stirring it up,” he said.
“The carbon stored in the seabed is important in keeping the atmosphere and climate change in check.”
Dr Harris said the study presents an opportunity to make a significant contribution to mitigating climate change impact.
“If the ocean is storing as much carbon as we think it is, and we are disturbing that carbon as much as we think we might be, then that gives us a massive opportunity to reduce that impact over time,” he said.
“We can create large marine protected areas based on carbon. It is globally relevant.
“In Europe we have loads of MPAs but most are trawled. We are asking, what is an MPA if it is trawled?”
He explained that Bermuda does not have bottom trawling in its waters.
Once the science is completed, Dr Harris said project partner the Blue Marine Foundation will take the open-source data and use it to ensure that informed decisions are made going forward on sustainable ocean use.
The four-strong crew participating in the Convex Seascape Survey gathered at Spanish Point Boat Club on a calm and sunny Wednesday morning ready for a day on the boat conducting research.
While the conditions above the water were perfect, those below on the sea floor posed some challenges for Ben Harris, the postdoctoral research fellow for the project, and his dive partner.
All aboard the boat captained by Chris Gauntlett, owner of Blue Water Divers, we stopped off at a location between Pearl Island and Morgan’s Point in the Great Sound, close to Somerset Bridge.
There, a range of activities took place including the dives to collect seabed samples which are essentially time capsules revealing the historical carbon make up of the seabed.
As he emerged from the 60-foot dive, Dr Harris said: “We are inside the bay here, it is a very thick, silty sediment. It all gets kicked up and there was zero visibility [visibility].
“We had to hold on to each other and keep our equipment close by. I put the little bell weight down and it buried itself into the sediment. It’s like trying to do your job in the dark.
“We would expect that in this area, there is no current. There is probably a bit more organic sediment in there than usual.”
Also as part of the science, water samples were collected, remotely-operated vehicles were dispatched as well as baited cameras to lure marine life into the path of their lens.
During their time in Bermuda, the team will complete about 36 dives in different areas and samples will undergo environmental DNA analysis.
Dr Harris added: “It will be trickier. We don’t have a lot of mud here and that is what we are looking for. We had to abandon a dive the other day as it was all coral. But we do have a lot of sand and calcareous ooze in Bermuda. It is inorganic carbon and we are interested to know how much there is, and what the inorganic components looks like.
“There wont be a marine protected area for carbon like this in Bermuda.”
Bermuda is looking to create different types of MPAs to help replenish fish stocks here through the Bermuda Ocean Prosperity Programme.
Dr Harris added: “As we are out here anyway, we designed our sampling plan to fall into the areas that are being applied to BOPP.
“We are providing preliminary data to help them in the future.”
Mr Catlin, who is also life president of Convex Group, referenced the work of Sir David Attenborough, the iconic British writer, broadcaster and naturalist, in highlighting the damaging effects of bottom trawling.
Sir David’s Ocean series showed for the first time on camera the weighted nets or dredges being towed along the seabed, leaving a trail of destruction behind them. The series also highlights large scale waste, as unintended catch is killed and thrown overboard.
The Convex survey builds upon research gathered from the Catlin Arctic Survey determining ice thickness and the Catlin Seaview Survey creating a baseline record of the world's coral reefs.
Mr Catlin told the Gazette: “This project is greater than the sum of the two former projects.
“It is slightly more difficult to sell — it’s all about mud — but we have a suspicion that the CO² absorption is far greater than people realise.
“I think this is a very good thing for us to do in Bermuda.”
The project fieldwork is scheduled to end next March and scientific papers will continue to be published until the early end of next year.
Paul Simons, the chief executive of Convex Group, spoke from the perspective of “an island boy, born and bred in Bermuda”.
He said: “Clearly the impacts of climate change are impacting places like Bermuda. We are seeing more frequent storms and the ferocity of those storms is greater.
“This study will help us get a deeper appreciation of the necessity for robust, timely and empirical data, and share that information for us all to make better decisions going forward.
“We only have one planet. I want my kids to live in a world where they feel comfortable knowing that we are doing all we can to try to subvert some of the things that are happening.”
• For more information about the Convex Seascape Study, visit convexseascapesurvey.com
The Convex Seascape Survey has attracted widespread media attention including:
• BBC
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