The carbon and nitrogen content of transparent exopolymer particles (TEP) was determined and related to the concentration of TEP as quantified by a colorimetrical method. TEP were produced in the laboratory from dissolved precursors by laminar or turbulent shear. Dissolved precursors were obtained by 0.2 μm filtration from diatom cultures, with or without nutrient reduction, and from natural di...

Increases in water temperature, as a result of climate change, may influence biogeochemical cycles, sediment-water fluxes and consequently environmental sustainability. Effects of rising temperature on dynamics of nitrate, nitrite, ammonium, dissolved inorganic nitrogen (DIN), dissolved reactive phosphorus (DRP), dissolved organic carbon (DOC) and gaseous nitrogen (N2 and N2O) were examined in ...

In vast regions of the ocean, a significant fraction of the vital nutrient phosphorus (P) in surface waters is associated with dissolved organic matter (DOM). Oceanic biological productivity in these regions is potentially dependent on the regeneration of bioavailable forms of P from DOM. Using tangential-flow ultrafiltration, high molecular weight (HMW) DOM samples were collected for chemical ...

The initial benthic degradation of senescent Zostera marina leaves was studied in controlled flowthrough microcosm chambers for 33 d. Sediment chambers without added eelgrass leaves served as control chambers. The inflowing artificial seawater and ouflowing seawater were analyzed for dissolved organic carbon and nitrogen (DOC and DON), total acid-hydrolyzable amino acids (THAA), dissolved free ...

Rotating biological contactors (RBCs) constitute a very unique and superior alternative for biodegradable matter and nitrogen removal on account of their feasibility, simplicity of design and operation, low land area requirement, low energy consumption, low operating and maintenance cost and treatment efficiency. The present review of RBCs focus on parameters that affect performance like rotati...

Biology and the environment interact, one shaping the other (1). In the oceans, the chemistry of seawater and the chemistry of life are intimately linked (2). In 1958, Alfred Redfield (3) noted that the microscopic plankton of the surface ocean contain carbon, nitrogen, and phosphorous atoms in a stoichiometry of ∼105:16:1 and that as these organisms sink and decay, the deep waters of the ocean...

The biodegradation module of a simulation program for municipal solid waste landfills (MODUELO) was developed. The biodegradation module carries out the balance of organic material starting with the results of the hydrologic simulation and the waste composition. It simulates the biologic reactions of hydrolysis of solids and the gasification of the dissolved biodegradable material. The results ...

Plant photosynthate fuels carbon-limited microbial growth and activity, resulting in increased rhizosphere nitrogen (N) mineralization. Most soil organic nitrogen is macromolecular (chitin, protein, nucleotides); enzymatic depolymerization is likely rate limiting for plant nitrogen accumulation. Analyzing Avena (wild oat) planted in microcosms containing sieved field soil, we observed increased...

We examined the flows of nitrogen in two batch incubations of plankton assemblages under controlled conditions, using mesopelagic seawater from different depths. Observations included concentrations of nutrients, organic matter (particulate and dissolved) and plankton (biomass by species). Because nitrogen flows were not observed directly (as is generally the case), we examined them using a mul...