In order to investigate sources and turnover rates of dissolved organic matter from Chesapeake Bay and Galveston Bay, colloidal organic matter (COM) was isolated using cross-flow ultrafiltration and subsequently characterized for its elemental (C, N, and S) and isotopic (13C and 14C) composition. Distributions of dissolved organic carbon (DOC) in Chesapeake Bay showed a non-systematic variation...

This research investigated a membrane bioreactor (MBR) process for removing biodegradable organic matter (BOM) and trihalomethane (THM) precursors from pre-ozonated water. Bench-scale and mini-pilot-scale MBR experiments were conducted using powdered activated carbon (PAC) and acclimated biomass. Dissolved organic carbon (DOC) was removed through a combination of adsorption and biodegradation m...

High-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with ultraviolet absorbance (UVA) and on-line dissolved organic carbon (DOC) detectors has been adapted and optimized under various conditions. An enhanced HPSEC-UVA system employing a modified commercially available DOC detector provides a better understanding of the qualitative and quantitative natural organic m...

Rivers are critical links in the carbon and nitrogen cycle in aquatic, terrestrial, and atmospheric environments. Here riverine carbon and nitrogen exports in nine large rivers on the Tibetan Plateau - the "Water Tower of Asia" - were investigated in the monsoon season from 2013 to 2015. Compared with the world average, concentrations of dissolved inorganic carbon (DIC, 30.7mg/L) were high in r...

Dissolved organic matter leached from decomposing organic matter is important in the leaching of nutrients from the root zone of ecosystems, eluviation of metals, and transport of hydrophobic pollutants. The objective of this study was to compare microbial mineralization rates in intact soil cores of various fractions of water-soluble dissolved organic matter. Uniformly 14C-labeled Populus frem...

[1] Surface waters of the Arctic Ocean have the highest concentrations of dissolved organic carbon (DOC) and terrigenous dissolved organic matter (DOM) of all ocean basins. Concentrations of dissolved lignin phenols in polar surface waters are 7-fold to 16-fold higher than those in the Atlantic and Pacific oceans, and stable carbon isotopic compositions of DOM are depleted in C by 1–2% relative...

Estuarine planktonic bacteria were incubated (bacterial bioassays) in water previously held in close contact with benthic sediments to assess the potential importance of benthic dissolved organic matter for planktonic bacterial production. The study was conducted using water and sediments collected from along a fresh to salt water gradient in the Parker River and Plum Island Sound Estuary in no...

The Deepwater Horizon oil spill triggered a complex cascade of microbial responses that reshaped the dynamics of heterotrophic carbon degradation and the turnover of dissolved organic carbon (DOC) in oil contaminated waters. Our results from 21-day laboratory incubations in rotating glass bottles (roller bottles) demonstrate that microbial dynamics and carbon flux in oil-contaminated surface wa...

Terrestrial ecosystems export large quantities of dissolved organic carbon (DOC) to aquatic ecosystems. This DOC can serve as a resource for heterotrophic bacteria and influence whether lakes function as sources or sinks of atmospheric CO2. However, it remains unclear as to how terrestrial carbon moves through lake food webs. We addressed this topic by conducting a comparative lake survey in th...

Soil labile organic carbon and soil enzymes play important roles in the carbon cycle of coastal wetlands that have high organic carbon accumulation rates. Soils under three vegetations (Phragmites australis, Spartina alterniflora, and Scirpusm mariqueter) as well as bare mudflat in Hangzhou Bay wetland of China were collected seasonally. Seasonal dynamics and correlations of soil labile organic...