[Campbell Biology P.751] The 'MAKE CONNECTIONS' section states that freshwater bivalves feed... | Practice Question

The 'MAKE CONNECTIONS' section states that freshwater bivalves feed on and reduce the abundance of photosynthetic protists and bacteria. If freshwater bivalves were to become extinct, what immediate ecological impact would likely occur in aquatic communities?

  • A: A decrease in water clarity due to an increase in photosynthetic protists and bacteria.
  • B: An increase in the dissolved oxygen levels in the water.
  • C: A reduction in primary productivity in the aquatic ecosystem.
  • D: Increased biodiversity as new filter-feeding species fill the vacant niche.

Explanation

Freshwater bivalves act as filter feeders, controlling the population of photosynthetic protists and bacteria. Their extinction would remove this natural control, leading to an unchecked proliferation of these microorganisms. This overgrowth, often referred to as an algal bloom, would reduce water clarity by making the water murky or opaque, and could also lead to oxygen depletion when these organisms die and decompose.