Dinitrogen fixation, the biological reduction in N2 gas to ammonia contributes to the supply of new nitrogen in the surface ocean. To understand the diversity and abundance of potentially diazotrophic (N2 fixing) microorganisms associated with marine zooplankton, especially copepods, the nifH gene was studied using zooplankton samples collected in the Pacific Ocean. In total, 257 nifH sequences...

Chemical interactions play a fundamental role in the ecology of marine foodwebs. Dimethyl sulfide (DMS) is a ubiquitous marine trace gas that acts as a bioactive compound by eliciting foraging behavior in a range of marine taxa including the copepod Temora longicornis. Production of DMS can rapidly increase following microzooplankton grazing on phytoplankton. Here, we investigated whether grazi...

Pristane (2,6,10,14-tetramethylpentadecane) concentrations in mussels (Mytilus trossulus) increase abruptly during spring in Prince William Sound (PWS), Alaska. This increase is mainly due to ingestion by mussels of pristane-laden feces produced by near-shore zooplanktivores, especially juvenile pink salmon (Oncorhynchus gorbuscha). Examination of the trophic and temporal distribution of prista...

Zooplankton has a non-random distribution in the pelagic community and exhibits various levels of patchiness (HAURY et al., 1978). Recently, particular attention has been focused on investigating the small-scale vertical and horizontal distribution of zooplankton assemblages which are important for monitoring marine processes and disturbances to marine ecosystems (PAFFENAn investigation into th...

Molecular approaches are widely applied in species identification and taxonomic studies of minute zooplankton. One of the most focused zooplankton nowadays is from Subclass Copepoda. Accurate species identification of all life stages of the generally small sized copepods through molecular analysis is important, especially in taxonomic and systematic assessment of harpacticoid copepod population...

The present paper aims to describe the spatial distribution of zooplankton copepods, their biomass and instantaneous secondary production, in Barra Bonita, a large eutrophic, polymitic reservoir (22 degrees 29' S and 48 degrees 34' W) on the Tietê River, of the Paraná basin. Sampling was carried out during two seasons: dry winter and rainy summer. Species composition, age structure and numerica...

Fish typically evoke a flight response in copepods. The behaviour of infective stage parasitic copepods, Lepeophtheirus salmonis, and adult holoplanktonic copepods, Acartia spp., in response to the approach of a rubber fish mimic was compared. Responses were scored as attacks if the copepod moved closer to the head or escapes if it moved further from the head. The parasite attacked the mimic in...

The carotenoid astaxanthin is a powerful antioxidant and a compound of vital importance for many marine organisms such as crustaceans and salmonids. Although astaxanthin deficiency may have serious consequences for ecosystem functioning, its origin and transfer in the food web have been little studied. Astaxanthin is produced by planktonic crustaceans, but these cannot synthesise carotenoid pig...

Planktonic copepods exhibit rapid escape behavior in response to hydrodynamic disturbances. Small disturbances of brief duration were produced by a piezoelectric transducer moving a small cylinder. The escape responses of free-swimming adult males and females of the copepods Acartia tonsa and A. lilljeborgii were recorded using high-speed video and quantified using computerized motion analysis ...

Metagenetics is a rapid and taxonomically comprehensive method for revealing community structures within environmental samples, based on large amounts of sequence data produced by high-throughput sequencers. Because community structures of planktonic copepods are important in the ocean owing to their high diversity and abundance, a metagenetic analysis of the 28S D2 region using Roche 454 was p...