21. In aquatic ecosystem, particulate organic matter (POM) is essential to which group of organisms?
A. Filter feeders
B. Deposit feeders
C. Grazers and shredders
D. None of the above
A. Filter feeders
To determine the answer to this question, we need to understand the role of particulate organic matter (POM) in an aquatic ecosystem. POM consists of small organic particles suspended in the water, such as dead organisms, feces, and decaying plant matter.
A. Filter feeders: These are organisms that filter out particles from the water to obtain their food. Many filter feeders, such as bivalves (clams, mussels) and some species of fish, rely on POM as a food source. They extract the organic material from the water and consume it.
B. Deposit feeders: These organisms obtain their food by consuming organic-rich sediments found at the bottom of bodies of water. Although deposit feeders mainly eat detritus and organic material that has settled on the bottom, they can also consume POM that has settled out of the water column.
C. Grazers and shredders: Grazers are organisms, such as some species of aquatic insects and certain fish, that feed on algae and other vegetation attached to rocks, reefs, or other submerged surfaces. Shredders are typically insects that consume leaf litter and other organic material in streams and rivers. While POM might not be their primary food source, it can still play a role in their diet.
Based on this information, the correct answer is C. Grazers and shredders. These organisms can benefit from the presence of particulate organic matter in an aquatic ecosystem, although other organisms like filter feeders and deposit feeders can also utilize POM to varying degrees. Therefore, option D, "None of the above," is not the correct answer.