We examined the chemical composition and bioavailability of dissolved organic carbon (DOC) and nitrogen (DON) from two pristine and two polluted cedar bog wetlands across three seasons. Pristine and polluted wetlands differed in DOC and DON concentrations, chemical characteristics, and bioavailability. DOC and DON concentrations were higher in the polluted than in the pristine wetlands. In cont...

Dissolved inorganic and organic nitrogen levels are elevated in aquatic systems due to anthropogenic activities. Dissolved organic nitrogen (DON) arises from various sources, and its impact could be more clearly constrained if specific sources were identified and if the molecular-level composition of DON were better understood. In this work, the pharmaceutical carbamazepine was used to identify...

[1] Here we describe, test, and apply a system of spatially explicit, global models for predicting river export of three dissolved organic matter (DOM) components: dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved organic phosphorus (DOP). The DON and DOP models represent the first attempt to model DON and DOP export in a spatially explicit, global manner. DOC, DON...

Seasonal and spatial distributions of extracellular enzymatic activities and microbial incorporations of dissolved organic substrates were followed in sediments of the brackish water Kiel Bight (Baltic Sea, Federal Republic of Germany). Enzymatic hydrolysis of polymeric organic compounds was determined by means of fluorogenic substrates (4-methylumbelliferyl-beta-d-glucoside, l-leucine-4-methyl...

Seawater from the northern Adriatic, with low phosphorus (0.03 WM) and nitrogen (1.0 WM NO3 and 1.0 WM NH4) concentration, was incubated for 12 days in 20-l polycarbonate carboys. The addition of a nutrient mixture (0.6 WM PO4, 5.1 WM NO3, 1.8 WM NH4, 10.6 WM SiO2) induced a strong diatom bloom, reaching 25 Wg l31 Chl a. Primary and bacterial production were stimulated by the initial enrichment...

A simple and generic method is developed to form organic nanoparticles in porous materials by solvent evaporation. The composites can be readily dissolved in water to produce aqueous organic nanoparticle dispersions.

The widespread occurrence of dissolved proteins as well as porin proteins was confirmed in water columns at five stations located in the North Pacific, the northern North Pacific, and the Bering Sea, where no investigation has heretofore been made with regard to dissolved protein. The major dissolved proteins detected in this study were determined to be glycosylated, based on the detection of a...