Production,composition and sedimentation of salp fecal pellets in oceanic waters

Rates of fecal pellet production have been recorded from seven species of oceanic salps feeding on natural diets. Expressed as g C defecated per mg salp body C per hour, the values range between 3.7 and 27.7. Carbon: nitrogen ratios of the salp fecal pellets average 11.4; the organic matter of the pellets is mainly protein and carbohydrate. Sinking velocities of the pellets are very high, ranging from 320 to 2 238 m d^-1 for pellets from three species. However, the pellets sink slower than would be predicted from extrapolation of rates for crustacean pellets, probably due to the shape of the pellets and their density. The high rates of defecation, large size and rapid sedimentation of salp fecal pellets make them likely mechanisms for rapid transport of small particulate matter from surface waters to deep water and the benthos.