Bacteria living 4000m below the ocean surface in the Clarion-Clipperton Fracture Zone (CCFZ) are consuming carbon dioxide and turning it into biomass, a new study shows.
by: Ocean News 30 Nov. 2018
Until now, scientists believed the main source of biomass on the seafloor was the organic matter that floated down towards the depths: dead fish, plankton and other detritus.
Prof. Andrew K. Sweetman from the Lyell Centre for Earth and Marine Science and Technology at Heriot-Watt University in Edinburgh said: “We have recently made two major findings.
“In contrast to similar studies in the north Atlantic Ocean, we found that bacteria and not seafloor animals were the most important organisms consuming organic detritus that floats down towards the ocean floor.
“We also discovered that benthic bacteria are taking up large amounts of carbon dioxide and assimilating it into their biomass through an unknown process. This was completely unexpected.
“Their biomass then potentially becomes a food source for other animals in the deep sea, so actually what we’ve discovered is a potential alternative food source in the deepest parts of the ocean, where we thought there was none.
“If we upscale our results to the global ocean, our findings reveal that 200 million tonnes of CO2 could be fixed into biomass each year by this process.
“This equates to approximately 10% of the CO2 that the oceans remove each year, so it’s possibly an important part of the deep-sea carbon cycle.
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