Final answer:
Most organic matter is found at the bottom of the sea due to marine snow, which is the continuous sinking of organic matter from the ocean surface. This organic matter serves as a source of nutrients for benthic organisms and contributes to nutrient cycling in the marine ecosystem.
Step-by-step explanation:
Most organic matter is found at the bottom of the sea because of a process called marine snow. Marine snow refers to the continuous shower of organic matter that sinks from the surface of the ocean to the seabed. This organic matter comes from the remains of dead organisms, fecal matter, and other organic materials that accumulate over time.
Marine snow provides a source of nutrients for benthic organisms, which are organisms that live on or near the seabed. These organisms break down the organic matter through decomposition and contribute to the overall cycling of nutrients in the marine ecosystem.
An example of this is the formation of oceanic dead zones, where high levels of organic matter lead to an increase in microbial activity that depletes oxygen levels, making it difficult for other marine organisms to survive.
Learn more about organic matter distribution in the sea