Sources of organic matter to the deep-sea benthos [plankton, nekton, macrophyte detritus, terrigenous matter, chemoautotrophic production]

Particulate organic matter (POM) in the deep sea is derived from five major sources: planktonic material, carcasses of large nekton, marine macrophyte detritus, terrigenous matter and chemoautotrophic production. The direct contribution of terrigenous matter to deep marine sediments is small. Sediment trap measurements show that small planktonic POM adds about 4 g C m⁻²yr⁻¹ to the deep-sea carbon pool. The maximum expected input of pelagic Sargassum to the deep Atlantic is one-tenth of this, 0.4 g C m⁻²yr⁻¹. Calculations suggest the remains of large nekton contribute approximately 50 mg C m⁻²yr⁻¹ while the rate of primary carbon synthesis by chemoautotrophs is estimated to be 0.01 to 0.1 mg C m⁻²yr⁻¹.