Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Entire DC Network
Seasonal Variability In The Bacteriolytic Capacity Of The Deposit Feeder Arenicola Marina: Environmental Correlates, C. J. Plante, Lawrence Mayer
Seasonal Variability In The Bacteriolytic Capacity Of The Deposit Feeder Arenicola Marina: Environmental Correlates, C. J. Plante, Lawrence Mayer
Marine Sciences Faculty Scholarship
Although deposit-feeding macrofauna consume and digest sedimentary bacteria, it is unclear whether feeding rates and digestion efficiencies are high enough to significantly impact the composition and abundance of bacteria in marine sediments. It is likely that both feeding rates and efficiency of digestion vary markedly through space and time. We used a turbidimetric assay to compare the rate of bacteriolysis by digestive fluids collected seasonally from the deposit-feeding polychaete Arenicola marina. Under standardized, experimental conditions, bacteriolytic rates represent concentrations of lytic agents. This concentration was found to vary significantly throughout the year (p = 0.001), showing greater than a 2x …
Dimethylsulfide (Dms) And Dimethylsulfoniopropionate (Dmsp) In Relation To Phytoplankton In The Gulf Of Maine, David Townsend, M. D. Keller
Dimethylsulfide (Dms) And Dimethylsulfoniopropionate (Dmsp) In Relation To Phytoplankton In The Gulf Of Maine, David Townsend, M. D. Keller
Marine Sciences Faculty Scholarship
Dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP), in both particulate and dissolved forms, were surveyed during the early spring (March and April) and summer (July) of 1991 in coastal and offshore waters of the Gulf of Maine, USA, along with the hydrography, inorganic nutrients, phytoplankton chlorophyll, and phytoplankton taxonomic composition and abundance. Concentrations as high as 15 nM DMS (in April and July), 208 nM particulate DMSP (in April), and 101 nM dissolved DMSP (in July) were recorded. Total DMSP (dissolved plus particulate) reached 293 nM in a patch of the dinoflagellate Katodinium sp. in April. This is the first …
Lability Of Proteinaceous Material In Estuarine Seston And Subcellular Fractions Of Phytoplankton, A. K. Laursen, Lawrence Mayer, David Townsend
Lability Of Proteinaceous Material In Estuarine Seston And Subcellular Fractions Of Phytoplankton, A. K. Laursen, Lawrence Mayer, David Townsend
Marine Sciences Faculty Scholarship
The rate of proteolysis of amino acids was used to assess the nutritional lability of various materials making up estuarine seston in 3 Maine, USA, estuaries. Physical separations of subcellular fractions of phytoplankton cells led to higher proteolysis rate constants for the cytoplasmic fraction (>1.2 h(-1)) than for the membrane fraction (0.2 to 1 h(-1)). Whole cells, copepod fecal pellets, bottom sediments, and estuarine seston had overlapping ranges of rate constants of 0.17 to 1.3 h(-1), which were indistinguishable from one another. Protein pools in the seston of these estuaries throughout the seasons were dominated by phytoplankton production and …