Anoxic Marine Basins:
According to scientists, anoxic marine basins may be among the most viable places to conduct large-scale carbon sequestration in the deep ocean.
- Anoxic Marine Basins is a body of water without oxygen.
- Permanent anoxic basins form when there is a strong layering of the water column created in a cup-like formation on the ocean floor.
- The layering is caused by density differences due to salt concentration or temperature.
- Once stratification occurs, circulation with the rest of the ocean is minimised, and microorganisms consume the oxygen in the water.
- In most anoxic basins, the water is extremely stagnant and can have mixing times of many thousand years.
- They range from a few hundred metres to several kilometres across and from 10 metres to 500 metres deeper than the surrounding seafloor.
- They can’t support animal life and are populated primarily by microbes and some very specialised fungi with different metabolisms than creatures in oxygen-rich environments.
- Some of them rely on molecules such as nitrate for respiration, and some get their carbon from gases like carbon dioxide (CO2) and methane (CH4) instead of eating other organisms or particles of organic matter.
- Many anoxic basins also contain toxic chemicals, which are produced by geothermal activity or by microbes living in the basins.
- Some also contain salt domes, big mounds of hardened salt.
- In some anoxic basins, methane and other gases collect in reservoirs beneath the seafloor.
- The gases can percolate upward, pushing up domes of sediment on the seafloor that are called mud volcanoes.
- The gases can burst through the soft sediments, creating “mini-eruptions” of wispy columns of sediment-filled water.
