Bacteria that live more than 4,000 feet (2.5 miles) below the surface of the Pacific Ocean absorb about 10 percent of carbon dioxide, which the ocean removes from the atmosphere every year.
The team "discovered that benthic bacteria occupy large amounts of carbon dioxide and assimilate them into their biomass through an unknown process." This was quite unexpected, "study author Andrew Switman said in a statement:" Their biomass then potentially becomes a source of food for other animals in the deep sea, so in fact what we discovered is a potential alternative food source in the deepest parts of the ocean, where we thought there was not one. "
Writing in oceanography and limnology, researchers say that benthic bacteria, rather than marine animals, could be "the most important organisms" that consume organic waste that floats to the ocean floor.
To investigate the cellular processes of benthic organisms, the team analyzed samples of sediment taken from the area in the eastern Pacific Ocean between Hawaii and Mexico, known as Clarion-Clipperton fracture zone (CCFZ), a deep marine ecosystem that is completely free from light , but flashes of bioluminescence and with a surprising biodiversity seabed. Bacteria here "dominated the consumption" of organic waste for one or two days. When scaling their results, it is equivalent to about 200 million tonnes of carbon dioxide that can be fixed in biomass each year, making the region a potentially important part in the deep-sea carbon cycle.
"We found the same activity in multiple research sites separated by hundreds of kilometers, so we can reasonably suppose this happens on the seabed in the eastern CCFZ and preferably throughout the CCFZ," Sweetman said.
The CCFZ is home to more than just deep sea sponges, marine anemones, shrimp and octopuses. According to the German bottom, the clay floor is filled with trillions of polymetallic nodules with a potato size that contain deposits of nickel, manganese, copper, zinc, cobalt and other minerals, according to Pew's beneficial trusts. It is an area rich in minerals that the International Seabed Authority has awarded 16 research contracts to groups interested in conducting research on future mining.
Assuming that the results can be applied to a larger CCFZ, the authors say their findings may have implications for extracting minerals in this region.
"If mining continues in the CCFZ, it will significantly disrupt the seabed environment," Sweetman said. "Only four experiments similar to ours have been carried out on the spot in the Abyssic regions of the oceans, we need to know much more about the biology of the seabed and ecology before we consider blasting the region."