Previous attempts to quantify copepod feeding have either been indirect (measuring the phytoplankton concentration before and after copepods were introduced to a sample), or direct (measuring the gut fluorescence of individual copepods feeding on phytoplankton). The disadvantage of the first method is that we obtain little information about the activities of individual copepods, and how their f...

The toxic diatom Pseudo-nitzschia seriata was exposed directly and indirectly (separated by a membrane) to copepods, Calanus hyperboreus and C. finmarchicus, to evaluate the effects of the copepods on domoic acid production and chain formation in P. seriata. The toxicity of P. seriata increased in the presence of the copepods. This response was chemically mediated without physical contact betwe...

The Antarctic Chilean peninsula, is characterized for being stable in its oceanographic conditions. Nevertheless, its coastal zones, such as bays, may have more variable physical conditions, both spatially and temporally. It has been observed that a remarkable interaction between the oceanographic conditions and spatial distribution patterns of zooplankton occurs. However, there is no good unde...

Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, ha...

Effects of turbulence on the dynamics of copepods as well as on the development of phytoplankton biomass were studied in 30 dm3 laboratory microcosms. Two experiments were carried out, with different successional stages of the plankton populations, using seawater from the Masnou nautical harbour, 20 km north of Barcelona. Two experimental conditions were established (stirred microcosms with cop...

Zooplankton from clear alpine lakes thrive under high levels of solar UV radiation (UVR), but in glacially turbid ones they are more protected from this damaging radiation. Here, we present results from experiments done with Cyclops abyssorum tatricus to assess UV-induced DNA damage and repair processes using the comet assay. Copepods were collected from three alpine lakes of differing UV trans...

The hypothesis that diatom carbon (C) produced during the spring peak supported spring zooplankton production and, ultimately, the growth of Coregonus lavaretus early larval stages from March to May 2006 in Lake Annecy, France, was tested using gut content analyses and fatty acid biomarkers. Gut content results showed that C. lavaretus larvae from stages 1 to 4 preferentially fed on copepods wi...

Patchiness of marine microbial communities has an important influence on microbial activities in the ocean, particularly in the oligotrophic open ocean where bioavailable nutrients are otherwise scarce. Such spatial heterogeneity is present in associations with dead and living particles, including zooplankton. The microbial community composition of mesozooplankton was investigated from the Sarg...

Several human pathogens and fecal-pollution indicators may persist as viable organisms in natural environments, owing to their ability to activate different types of survival strategies. These strategies include adhesion on both abiotic and biotic surfaces and the entrance to the so-called viable but nonculturable (VBNC) state. In an 18-month survey for the detection of enterococci in both lake...

The larval development of the nematode Contracaecum rudolphii (Rudolphi, 1819), a common parasite of the proventriculus of cormorants, was experimentally studied. Within the eggs cultivated in freshwater under laboratory temperatures of 20-22 degrees C, the developing larva undergoes two moults on days 4-5, attaining the third larval stage. Most of the ensheathed third-stage larvae, 291-457 mic...