![]() ![]() It is this sequestered carbon that is responsible for ultimately lowering atmospheric CO 2. The particles that escape these processes entirely are sequestered in the sediment and may remain there for millions of years. The fixed carbon that is decomposed by bacteria either on the way down or once on the sea floor then enters the final phase of the pump and is remineralized to be used again in primary production. It is this aggregation that gives particles a better chance of escaping predation and decomposition in the water column and eventually making it to the sea floor. The sinking particles will often form aggregates as they sink, greatly increasing the sinking rate. Once this carbon is fixed into soft or hard tissue, the organisms either stay in the euphotic zone to be recycled as part of the regenerative nutrient cycle or once they die, continue to the second phase of the biological pump and begin to sink to the ocean floor. coccolithophores and foraminifera) combine calcium (Ca) and dissolved carbonates ( carbonic acid and bicarbonate) to form a calcium carbonate (CaCO 3) protective coating. In these surface waters, phytoplankton use carbon dioxide (CO 2), nitrogen (N), phosphorus (P), and other trace elements ( barium, iron, zinc, etc.) during photosynthesis to make carbohydrates, lipids, and proteins. The biological pump can be divided into three distinct phases, the first of which is the production of fixed carbon by planktonic phototrophs in the euphotic (sunlit) surface region of the ocean. This transfer occurs through physical mixing and transport of dissolved and particulate organic carbon (POC), vertical migrations of organisms ( zooplankton, fish) and through gravitational settling of particulate organic carbon. The biological pump depends on the fraction of primary produced organic matter that survives degradation in the euphotic zone and that is exported from surface water to the ocean interior, where it is mineralized to inorganic carbon, with the result that carbon is transported against the gradient of dissolved inorganic carbon (DIC) from the surface to the deep ocean. The biological pump is a set of processes that transfer organic carbon from the surface to the deep ocean, and is at the heart of the ocean carbon cycle. ![]() The ocean plays a fundamental role in Earth's carbon cycle, helping to regulate atmospheric CO 2 concentration. ![]() It is also intimately linked to the cycling of other elements and compounds. This flow of carbon is referred to as the Earth's carbon cycle. It is capable of moving among and between the geosphere, cryosphere, atmosphere, biosphere and hydrosphere. The element carbon plays a central role in climate and life on Earth. Scavenging: DOC incorporation within sinking particles. Below 1000 m depth carbon is considered removed from the atmosphere for at least 100 years. Pump processes vary with depth Photic zone: 0–100 m Mesopelagic: 100–1000 m Bathypelagic: 1000 to abyssal depths. An ocean without a biological pump would result in atmospheric carbon dioxide levels about 400 ppm higher than the present day. This takes carbon out of contact with the atmosphere for several thousand years or longer. Overall, the pump transfers about 10.2 gigatonnes of carbon every year into the ocean's interior and a total of 1300 gigatonnes carbon over an average 127 years. The biological pump is not so much the result of a single process, but rather the sum of a number of processes each of which can influence biological pumping. īudget calculations of the biological carbon pump are based on the ratio between sedimentation (carbon export to the ocean floor) and remineralization (release of carbon to the atmosphere). It is the part of the broader oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO 3) formed into shells by certain organisms such as plankton and mollusks (carbonate pump). The biological pump is the biological component of the "marine carbon pump" which contains both a physical and biological component. In other words, it is a biologically mediated process which results in the sequestering of carbon in the deep ocean away from the atmosphere and the land. The biological pump (or ocean carbon biological pump or marine biological carbon pump) is the ocean's biologically driven sequestration of carbon from the atmosphere and land runoff to the ocean interior and seafloor sediments. ![]()
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