The transport and deposition of anthropogenic nitrogen (N) to downwind ecosystems is significant and can be a dominant source of new N to many watersheds. Bacterially mediated denitrification in lake sediments may ameliorate the effects of N loading by permanently removing such inputs. We measured denitrification in sediments collected from lakes in the Colorado Rocky Mountains (USA) receiving ...

Nitrogen (N) dynamics were evaluated from 1 June 1995 through 31 May 1996 within the Arbutus Lake watershed in the Adirondack Mountains of New York State, U.S.A. At the Arbutus Lake outlet dissolved organic nitrogen (DON), NO3 and NH + 4 contributed 61%, 33%, and 6% respectively, to the total dissolved nitrogen (TDN) flux (259 mol ha−1 yr−1). At the lake inlet DON, NO3 , and NH + 4 constituted ...

Both nitrate (NO3-N) and ammonia (NH4-N) concentrations are in general highly variable during a lake’s seasonal cycle. During the growing seasonal peak, such concentrations can be very low due mainly to its’ sequestration by phytoplankton. With the aim to study NO3-N and NH4-N mean concentration variation along the increase of the trophic state of lakes, this study simultaneously analyses the i...

Here we report on three years (1996-1998) of measurements of organic and inorganic nitrogen (N) fluxes to and from Green Lakes Valley, a high-elevation ecosystem in the Colorado Front Range of the Rocky Mountains. Nitrate-N (NO3−N) was the dominant form of N in both precipitation and streamwater. Annual precipitation contained 52% NO3−N, 32% ammonium-N (NH4−N), 9% dissolved organic N (DON), and...

Additional Index Words: rate constant, zero-order reaction, firstorder reaction, submerged soil, available carbon. A theoretical analysis of denitrification occurring in submerged soil in a test tube, when assumed to be a zero-order reaction with available ———————————————————— organic carbon nonlimiting, appears to be a first-order reaction if the __ , , , , c effects of diffusion are neglected...

The steady-state First-order Acidity Balance (FAB) model for calculating critical loads of sulphur (S) and nitrogen (N) is applied to 609 Norwegian soft-water lakes to assess the future nitrate (NO3 -) leaching potential under present (1992-96) S and N deposition. The lakes were separated into five groups receiving increasing levels of N deposition (<25, 25-49, 50-74, 75-99 and 100-125 meq m-2 ...

Monomeric [Co(II)(hep-H)(H2O)4]SO4 [1]SO4 and [Co(II)(hep-H)2(H2O)2](NO3)2 [2](NO3)2 have been developed from 2-(2-hydroxyethyl)pyridine (hep-H) and CoSO4·7H2O/Co(NO3)2·6H2O, respectively, at 298 K. On exposure to heat (120 °C), the light orange single crystal of [1]SO4 transforms to a pink single crystal corresponding to the neutral sulfato bridged dimeric complex [(Co(II)(hep-H)(H2O)2(μ2-sulf...

Groundwater contamination was characterised using a methodology which combines shallow groundwater geochemistry data from 17 piezometers over a 2 yr period in a statistical framework and hydrogeological techniques. Nitrate-N (NO3-N) contaminant mass flux was calculated across three control planes (rows of piezometers) in six isolated plots. Results showed natural attenuation occurs on site alth...