The relationship between the partial pressure of carbon dioxide (pCO2) and dissolved organic carbon (DOC) concentration in Brazilian lakes, encompassing 225 samples across a wide latitudinal range in the tropics, was tested. Unlike the positive relationship reported for lake waters, which was largely based on temperate lakes, we found no significant relationship for low-latitude lakes (< 33), d...

The least known component of the `biological pumpa is the active transport of carbon and nutrients by diel vertical migration of zooplankton. We measured CO 2 respiration and dissolved organic carbon (DOC) excretion by individual species of common vertically migrating zooplankton at the US JGOFS Bermuda Atlantic Time-series Study (BATS) station. The inclusion of DOC excretion in this study buil...

The study of molecular transformation processes of dissolved organic carbon (DOC) in the environment significantly contributes to a better understanding of the global biogeochemical organic matter cycle. In an oxic karst groundwater system, in which the most powerful abiotic DOC degradative reactions, photodegradation and metal-mediated redox chemistry, are at best marginal contributors, a near...

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...

The Catskill Mountains of southeastern New York State have among the highest rates of atmospheric nitrogen deposition in the United States. Some streams draining Catskill catchments have shown dramatic increases in nitrate concentrations while others have maintained low nitrate concentrations. Streams in which exchange occurs between surface and subsurface (i.e. hyporheic) waters are thought to...

Concentrations of dissolved organic carbon (DOC) and particulate organic carbon (POC) were analysed from the source to the mouth of the River Sebangau in Central Kalimantan, Indonesia during the dry and wet seasons in 2008/2009 and an annual total organic carbon (TOC) flux estimated. DOC concentrations were higher and POC concentrations lower in the wet season compared to the dry season. As see...

[1] We report on the water column biogeochemistry in adjacent mangrove and seagrass systems in Gazi Bay (Kenya), with a focus on assessing the sources and cycling of organic and inorganic carbon. Mangrove and seagrass-derived material was found to be the dominant organic carbon sources in the water column, and could be distinguished on the basis of their dC signatures and particulate organic ca...

Surface hydrographic and biogeochemical properties were measured contemporaneously at high spatial density during a w x transit from Chesapeake Bay, across the Middle Atlantic Bight MAB and Gulf Stream to the Sargasso Sea near Bermuda w x from 28 September–2 October 1996. Discrete samples were collected for total organic carbon TOC , dissolved organic w x w x w x w x carbon DOC , total organic ...

Due to high terrestrial runoff, the Baltic Sea is rich in dissolved organic carbon (DOC), the light-absorbing fraction of which is referred to as colored dissolved organic matter (CDOM). Inputs of DOC and CDOM are predicted to increase with climate change, affecting coastal ecosystems. We found that the relationships between DOC, CDOM, salinity, and Secchi depth all differed between the two coa...

[1] Photomineralization of terrigenous dissolved organic matter (tDOM) in the Arctic Ocean is limited by persistent sea ice cover that reduces the amount of ultraviolet (UV) radiation reaching the underlying water column. UV-dependent processes are likely to accelerate as a result of shrinking sea ice extent and decreasing ice thickness caused by climatic warming over this region. In this study...