Effects of temperature on two psychrophilic ecotypes of a heterotrophic nanoflagellate, Paraphysomonas imperforata

Article Abstract:

The protozoon Paraphysomonas imperforata has psychrophilic ecotypes that exhibit different responses to different degrees of low temperature. These responses are demonstrated in their growth rates, ingestion rates, and cell sizes as shown in this laboratory study of flagellates isolated from Newfoundland coastal waters and the Arctic Ocean. The adaptability of these protozoa to different environmental conditions seems to have produced ecological types thatare different physiologically and genetically. Adaption of Paraphysomonas imperforata to cold temperature suggests its tolerance to specific temperature it was exposed to over a long period of time. This study shows the similar characteristics of the two flagellate ecotypes that vary in their response rates due to the altitude and different temperatures of their geographic sources.

Microbial ecology, Protozoa, Protozoans

Effects of UV-A (320 to 399 nanometers) on grazing pressure of a marine heterotrophic nanoflagellate on strains of the unicellular cyanobacteria Synechococcus spp

Article Abstract:

A study was conducted to confirm if UV-A alone has the capacity to suppress grazing of Paraphysomonas bandaiensis on Synechococcus spp. To evaluate the effect of UV-A on the influence of nanoflagellate grazing on a Synechococcus primary production was the other objective. Results revealed that UV-A alone, as opposed to treatment combining it with UV-B, impacts the composition and biomass of marine microbial communities by influencing predator-prey interactions and primary production.

Ultraviolet radiation, Cyanobacteria, Plankton populations

Significance of size and nucleic acid content heterogeneity as measured by flow cytometry in natural planktonic bacteria

Article Abstract:

Size and nucleic acid content heterogeneity measured by flow cytometry in natural planktonic bacteria are discussed. Different methods for counting the planktonic bacteria using epifluorescence microscopy and flow cytometry are compared. The high-DNA bacteria are the dynamic members in the bacterial community. The active cell index (ACI) is a valid estimate of the fraction of actively metabolizing bacteria in natural plankton communities.

United States, Sweden, Statistical Data Included, Usage, Measurement, Flow cytometry, Food chains (Ecology), Food chains, Nucleic acids, Plankton, Planktonic bacteria