Ocean Detritivores: Recycling the Marine Snow

Detritivores are the ocean's recyclers, consuming marine snow (falling organic particles) and settled detritus. They sustain the biological pump and nutrient cycles.

Major Functional Groups

1. Deposit Feeders – Ingest sediment + organic matter.
   • Polychaete worms (lugworms, terebellids)
   • Amphipods, isopods
   • Bivalves (clams, tellins – some switch between filter/deposit)
   • Sea cucumbers (holothurians) – vacuum cleaners of abyssal plains
2. Filter / Suspension Feeders – Capture particles from water column.
   • Barnacles, mussels, oysters, clams
   • Bryozoans, tunicates, sponges
   • Anchovies, sardines, menhaden, whale sharks, manta rays
3. Scavengers (Necrophages) – Consume large carrion.
   • Hagfish, sleeper sharks, amphipods (whale falls)
   • Gulls, petrels, albatrosses (surface)
   • Crabs, lobsters
4. Microbial Decomposers – The unseen majority.
   • Bacteria (Proteobacteria, Bacteroidetes) – hydrolyze polymers.
   • Archaea – anaerobic niches.
   • Fungi (chytrids, yeasts) – degrade refractory compounds.
5. Deep-Sea Specialists – Adapted to high pressure, low temp, no light.
   • Abyssal holothurians, ophiuroids, giant isopods, amphipod swarms
   • Osedax (bone-eating worms) on whale falls.
6. Wood Borers – Unique niche.
   • Shipworms (Teredinidae – bivalves)
   • Gribbles (Limnoriidae – isopods)

Ecosystem Impact

• Remineralize C, N, P, Si → fuel primary production.
• Sequester carbon via fecal pellets sinking to deep sea.
• Structure sediments (bioturbation) → oxygen penetration.
• Support fisheries (forage fish → predators).

Without detritivores, the ocean would suffocate in its own waste. They are the metabolic engine of the planet.