Why are the oceans considered a large carbon sink?
Phytoplankton takes in carbon through cellular
respiration.
Water absorbs carbon directly from the atmosphere by diffusion.
Carbon gets transferred among all the organisms of every food chain.
Decomposition rates in the water are far greater than on land.
All of the given options contribute to the oceans being considered a large carbon sink.
Phytoplankton takes in carbon through cellular respiration: Phytoplankton, which are microscopic plants, undergo photosynthesis and convert carbon dioxide into organic carbon. When they respire, they release some carbon dioxide back into the water, but overall, they absorb more carbon dioxide than they release, making them a net carbon sink.
Water absorbs carbon directly from the atmosphere by diffusion: The surface of the ocean acts as a barrier, allowing carbon dioxide from the atmosphere to dissolve into the water through diffusion. This process is facilitated by the large surface area of the oceans.
Carbon gets transferred among all the organisms of every food chain: Carbon is transferred among organisms in the marine food chain through consumption and excretion. Each time an organism eats another organism, it takes in and stores the carbon from their prey. This transfer occurs throughout the food chain, from primary producers, such as phytoplankton, to top predators.
Decomposition rates in the water are far greater than on land: Dead organisms and organic matter in the oceans can be decomposed by bacteria and other microorganisms at a faster rate than on land. This leads to the breakdown of organic carbon and its release as carbon dioxide back into the water. However, the overall uptake of carbon by marine organisms exceeds the carbon released through decomposition, making the oceans a net carbon sink.