Feeding behavior of the copepod Temora turbinata: clearance rate and prey preference on the diatom and microbial food web components in coastal area

Feeding behavior of Temora turbinata was investigated through laboratory experiments with special emphasis on its food preference and consequent clearance rate on diatom and microbial components given as common natural food assemblage of coastal area (Uchiumi, Uwa Sea, Japan). Among available prey items, T. turbinata showed the highest clearance rate for Thalassiosira spp. (0.23 ± 0.08 L Temora -1 day -1 ) followed by Chaetoceros spp. (0.11 ± 0.03 L Temora -1 day -1 ), but clearance rates for other diatom, Nitzschia spp. was lower (0.03 to 0.07 L Temora -1 day -1 ). Bacterial abundances showed no response against 24-h feeding of T. turbinata. Feeding of T. turbinata on heterotrophic nanoflagellates (HNF) was appar ent when clearance rates of T. turbinata on diatoms were relatively low, but T. turbinata did not consume HNF as well as ciliates with Thalassiosira spp. of which clearance rate was highest. The results suggest that HNF and ciliates are possible supplementary prey item for T. turbinata, but their contribution as food sources can be limited by the presence of other prey items such as preferable diatom species.