Why are bivalves important to marine food webs?

Bivalves play a vital role in marine food webs primarily as primary consumers that bridge the gap between microscopic organic matter and higher-level predators.1

• Filter Feeding: Most bivalves are suspension feeders that use modified gills, known as ctenidia, to filter plant detritus, bacteria, and algae from the water column or sediment surface. By consuming these microscopic organisms, they effectively channel energy from the base of the food web into the broader ecosystem.12
• Prey Source: Because they are often abundant—sometimes dominating entire habitats like rocky coasts or soft shores—bivalves serve as a critical food source for many marine predators, including crustaceans, starfishes, and snails.13
• Nutrient Cycling: By occurring in high densities, bivalves can significantly influence nutrient cycles within their environments.3

While most bivalves occupy this role as primary consumers, some specialized deep-sea species have evolved to become predators, feeding on small crustaceans and worms. Conversely, some bivalves, such as the invasive zebra mussel, can disrupt established food webs by rapidly consuming resources and altering the ecological balance of their surroundings.124