Benthic Metabolism in Fluvial Sediments with Larvae of Lampetra sp.

Lampreys spend their larval stage within fine sand fluvial sediments, where they burrow and act as filter feeders. Lamprey larvae (ammocoetes) can significantly affect benthic-pelagic coupling nutrient cycling in rivers, due to high densities. However, bioturbation, feeding excretion activities are still poorly explored. These aspects were investigated by means of laboratory incubations intact sediments added with ammocoetes animals alone. Oxygen respiration, fluxes rates determined. Individual ammocoete suggested that biomass-specific oxygen consumption ammonium, reactive phosphorus silica size-dependent, greater small compared large individuals. The comparison metabolic measured revealed activity decreases when burrowed sediments. Furthermore, results suggest a major fraction ammonium excreted was assimilated benthic microbes or microalgae overcome situ N-limitation. Alternatively, part the oxidized denitrified nitrate uptake rather increased along density. Ammocoetes but such production not apparent bioturbated likely microbial microalgal immobilization