biodeposition

Biodeposition is the deposition of organic matter into sediments as a result of biological processes, most commonly produced by suspension-feeding and detritivorous organisms. It encompasses fecal material, pseudofeces, and other organic particulates released by organisms as they feed or decay, which settle to the seabed or lakebed and contribute to the sediment organic matter pool.

In aquatic systems, biodeposition occurs when organisms such as oysters, mussels, or deposit-feeding worms produce waste that aggregates on the bottom. The rate depends on organism density, feeding mode, water flow, and ambient productivity. Biodeposits can consist of fine organic particles and microbes, and they influence the geochemical and physical properties of sediments, including grain size distribution, porosity, and redox conditions.

Ecologically, biodeposition affects nutrient cycling, carbon remineralization, and sediment oxygen demand, and can alter microbial activity and mineralization rates at the sediment-water interface. It helps transfer carbon and nutrients from the pelagic zone to the benthos, shaping benthic-pelagic coupling and local ecosystem productivity.

In human activities, biodeposition is a central consideration in aquaculture and environmental management. High biodeposition from intensive farming can elevate the organic load on the seabed, increasing ammonia production and oxygen consumption, which may lead to hypoxic conditions. Management strategies include optimizing feeding efficiency, controlling stocking density, siting farms to minimize accumulation, and monitoring sediment organic content and pore-water chemistry.

Measurement and study of biodeposition involve quantifying the mass of organic matter deposited per unit area per time, using sediment traps, biodeposition chambers, or modelling approaches. The concept integrates marine ecology, biogeochemistry, and environmental management.