Index Catalog // ScholarsArchive@OSU

Creator:: Sherr, Evelyn, Sherr, Barry F., and Sigmon, Crystal T.
Abstract:: We evaluated the extent to which the average metabolic activity of open ocean bacterioplankton changed during 2 to 3 d incubations of 1 μm filtered seawater at in situ temperature. Indices of bacterial activity during incubation experiments were compared to those of in situ bacterioplankton, which were repeatedly sampled at...
Resource Type:: Article

Creator:: Sherr, Barry F., del Giorgio, Paul, and Sherr, Evelyn
Abstract:: The redox dye 5-cyano-2, 3-ditolyl tetrazolium chloride (CTC) is used in aquatic sciences as a vital stain for enumeration of respiring bacteria in situ. Questions concerning its efficacy have been raised. We propose that the abundance of CTC-positive (CTC+) bacteria is a useful parameter in microbial ecology based on the...
Resource Type:: Article

Creator:: Sherr, Evelyn and Sherr, Barry F.
Abstract:: Recent data on seasonal variation in the concentration of atmospheric oxygen are independent evidence for a marked annual cycle in the production/respiration (P/R) ratio of the biotic community of the ocean in both the northern and southern hemispheres. Based on the oxygen data, the P/R ratio tends to be >1...
Resource Type:: Article

Creator:: Wolfe, Gordon V., Sherr, Evelyn, and Sherr, Barry F.
Abstract:: Degradation and release to solution of intracellular dimethylsulfoniopropionate (DMSP) from Emiliania huxleyi 370 was observed during grazing by the heterotrophic dinoflagellate Oxyrrhis marina in 24 h bottle incubations. Between 30 and 70 % of the lost algal DMSP was metabolized by the grazers without production of dimethylsulfide (DMS) when grazer...
Resource Type:: Article

Creator:: Gonzalez, Juan M., Sherr, Evelyn, and Sherr, Barry F.
Abstract:: Previous work has demonstrated selective feeding by bacterivorous protists on the of prey size. Other prey characteristics may also affect protist grazing rates. In this relative uptake rates of fluorescently labeled bacterial (FLB) cells made from starving bacteria (S-FLB), and of live-stained motile vs non-motile bacteria by marine We also...
Resource Type:: Article

Creator:: Gonzalez, Juan M., Sherr, Barry F., and Sherr, Evelyn
Abstract:: We propose quantification of the activity of digestive enzymes as a novel way to estimate rates of protist grazing in natural waters. Our first application of this approach was determination of protistan bacterivory by assaying the activity of lysozyme at acid pH. Lysozyme specifically degrades peptidoglycan, a major structural component...
Resource Type:: Article

Creator:: Tranvik, Lars J., Sherr, Evelyn, and Sherr, Barry F.
Abstract:: A variety of macromolecules labeled with FITC (fluorescein isothiocyanate), including carbohydrates (dextran) and proteins (ferritin, casein, albumin, concavalin A), spanning a range of molecular weights from 55 to 2000 kD, were actively ingested by marine heterotrophic flagellates at substrate concentrations of 1 to 10 mg/L. The uptake capacity for the...
Resource Type:: Article

Creator:: Suzuki, Marcelino T., Sherr, Evelyn, and Sherr, Barry F.
Abstract:: We compared estimates of bacterial abundance and of average bacterial cell size based on direct counts of bacterioplankton cells stained with acridine orange (AO) or 4’-6-diamidino-2-phenylidole (DAPI). Estimates of numbers mll–1 of bacteria stained with DAPI were on average 70% (range 57–82%) of bacterial counts made with AO as the...
Resource Type:: Article

Creator:: Sherr, Barry F., Sherr, Evelyn, and McDaniel, Julie
Abstract:: Grazing by phagotrophic flagellates and ciliates is a major source of mortality for bacterioplankton in both marine and freshwater systems. Recent studies have demonstrated a positive relationship between clearance rate and prey size for bacterivorous protists. We tested the idea that, by selectively grazing the larger (more actively growing or...
Resource Type:: Article

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