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Arctic seafloor sediment key to atmospheric carbon recycling

In the media

The Arctic is “a bellweather, or a sentinel” for global climate changes in general – and with rapid sea ice melt occurring there, the area is becoming increasingly accessible to researchers and other interested parties, Leeds’ Dr Christian März told the BBC’s Paul Hudson.

With the opening up of the Arctic making the region more accessible to fisheries, shipping routes and oil and gas exploration, there is a “clear trend” that the UK is building capacity there, Dr März said, citing the new polar research vessel, the RSS Sir David Attenborough (of “Boaty McBoatface” fame), a floating laboratory capable of lasting 60 days at  sea without resupply.

Dr März, Principal Investigator of the NERC-funded ChAOS (Changing Arctic Ocean Seafloor) project – one of a suite of four projects in a £10m NERC investigation into climate change in the Arctic Ocean commencing this month – was interviewed on Paul Hudson’s Weather Show on Sunday 25 February. Describing the accelerated warming, he explained that the extreme environment of the Arctic strongly amplifies warming around the globe, with the resulting decline in sea ice having implications for the entire region and, potentially, more widely.

Referring to his own monitoring of meteorological observations of the Arctic – temperatures 20C higher than the seasonal average have been recorded this year – Paul Hudson said, “It’s clear the Arctic Ocean is in long-term decline.”

The retreat of the sea ice has consequences for atmospheric carbon recycling, explained Dr März, Associate Professor in Biogeochemistry at the School of Earth and Environment.

“The reason we are interested in the seafloor is that it is the ultimate sink for carbon – atmospheric CO2 –  over long geological time scales. Most of the carbon that arrives at the sea floor at the Arctic, in terms of sediments, will essentially be removed from the atmosphere. Retreating sea ice exposes more water to sunlight so more algae can grow, more carbon sinks to the sea floor, more carbon can get buried and that removes CO2, so its a good thing.”

However, not all carbon gets buried, said Dr März. “A lot of it gets eaten up by microrobes, like in your compost heap in the garden – and that also releases various nutrients that everything that lives within the water column needs.”

The resulting algal blooms  cause a greening of the ocean and have great importance to the food chain and carbon cycling. “We are really interested in how this balance between the burial of carbon and the recycling of nutrients into the water column changes as the sea ice is retreating.”