For decades, heavy metals have been deposited into marine sediments as a result of anthropogenic activities. Depending on their bioavailability, these metals may represent a risk to benthic organisms. Dissolved interstitial water metal concentrations have been shown to be better predictors of bioavailability than sediment metal concentrations. In order to improve our understanding of metals bio...

Despite the importance of incubation assays for studies in microbial ecology that frequently require long confinement times, few reports are available in which changes in the assemblage structure of aquatic prokaryotes were monitored during long-term incubations. We measured rates of dissolved organic carbon degradation and microbial respiration by consumption of dissolved oxygen (DO) in four e...

The location and magnitude of oceanic iron sources remain uncertain owing to a scarcity of data, particularly in the Arctic Ocean. The formation of cold, dense water in the subsurface layer of the western Arctic Ocean is a key process in the lateral transport of iron, macronutrients, and other chemical constituents. Here, we present iron, humic-like fluorescent dissolved organic matter, and nut...

In natural waters, the equilibrium state of hydrophobic organic compounds among bottom sediment (BS), suspended sediment (SPS), and water is fundamental to infer their transfer flux and aqueous bioavailability. However, this type of information remains scarce and fragmented. This study systematically evaluated the equilibrium state of polycyclic aromatic hydrocarbons (PAHs) in the Yangtze River...

Understanding how the concentration and chemical quality of dissolved organic matter (DOM) varies in soils is critical because DOM inXuences an array of biological, chemical, and physical processes. We used PARAFAC modeling of excitation–emission Xuorescence spectroscopy, speciWc UV absorbance (SUVA254) and biodegradable dissolved organic carbon (BDOC) incubations to investigate the chemical qu...

Hansell, D.A., 1993. Results and observations from the measurement of DOC and DON in seawater using a high-temperature catalytic oxidation technique. Mar. Chem., 41: 195-202. Operating temperatures for the high-temperature catalytic oxidation of dissolved organic matter (DOM) in seawater were evaluated for optimization of total dissolved nitrogen analysis. In addition, the possibility of NO2 be...

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 ...

Phosphorus (P) contributes to eutrophication of surface waters and buffer strips may be implemented to reduce its transfer from agricultural sources to watercourses. This study was conducted to test the hypothesis that soil type and slope influence the retention of dissolved organic P and inorganic orthophosphate in agricultural runoff in 2-m-wide buffer strip soils. A solution, comprised of di...

Organic decomposition is a complex interaction between chemical, physical and biological processes, where the variety of aquatic vascular plants is essential for the trophic dynamics of freshwater ecosystems. The goal of this study was to determine the aquatic macrophyte Eichhornia azurea (Sw.) Kunth decomposition rate, the time relation with the limnological parameters, and whether this relati...

Photochemical and microbial degradation of external inputs of dissolved organic matter (DOM) from both natural (forests) and anthropogenic (swine and equine pastures) non-point sources to rivers were examined through field and laboratory microcosm experiments. Little or no photochemical degradation of DOM to inorganic N or P occurred in either the agricultural or forest runoff. The dissolved or...