We report a synchronous increase in accumulation of reduced inorganic sulfur since c. 1980 in sediment cores from eight of nine lakes studied in the Canadian Arctic and Svalbard (Norway). Sediment incubations and detailed analyses of sediment profiles from two of the lakes indicate that increases in sulfur accumulation may be due ultimately to a changing climate. Warming-induced lengthening of ...

The geochemical processes of mercury in Dongfeng (DF) and Wujiangdu (WJD) reservoirs, which were constructed in 1992 and 1979, respectively in Wujiang River, which is the upper branch of Yangtze River were investigated. One sampling site was chosen up river of 1 km from the dam for each reservoir. Three sampling campaigns were conducted at these sampling sites in December 2003, April 2004 and J...

As part of a larger study of mercury (Hg) biogeochemistry and bioaccumulation in agricultural (rice growing) and non-agricultural wetlands in California's Central Valley, USA, seasonal and spatial controls on methylmercury (MeHg) production were examined in surface sediment. Three types of shallowly-flooded agricultural wetlands (white rice, wild rice, and fallow fields) and two types of manage...

To predict erosion rates throughout the Andes, we conducted a multiple regression analysis of the sediment discharge from 47 drainage basins in the Bolivian Andes and various topographic, climatologic, and geologic parameters. These mountainous basins are typically large (17–81,000 km; km), often have decades of measurement mean p 11,000 data on daily water and sediment discharge, and display a...

Annual rates of sediment denitrification and sediment–water fluxes of oxygen and nutrients were quantified at two shallow locations, Virksund and Ulbjerg, in the Limfjorden, Denmark. The sediment was sandy and colonized mainly by bivalves with a wet weight of 2,508 g m22 at Virksund and 572 g m22 at Ulbjerg. A benthic microalgal community was present throughout the year, and for 1–2 months in t...

The seasonal variation and depth distribution of the capacity for denitrification and dissimilatory NO(3) reduction to NH(4) (NO(3) ammonification) were studied in the upper 4 cm of the sediment of Norsminde Fjord estuary, Denmark. A combination of C(2)H(2) inhibition and N isotope techniques was used in intact sediment cores in short-term incubations (maximum, 4 h). The denitrification capacit...

Net-pen salmon aquaculture has well-known effects on coastal ecosystems: farm waste increases sediment organic content and the incidence of sediment anoxia, supports increased production of deposit-feeding invertebrates, and attracts higher densities of demersal fish and other mobile carnivores. These impacts are widely considered to be localized and transitory, and are commonly managed by impo...

Seasonal turbidity patterns and event-level hysteresis analysis of turbidity verses discharge in four 1 km headwater catchments in California’s Sierra Nevada indicate localized in-channel sediment sources and seasonal accumulation-depletion patterns of stream sediments. Turbidity signals were analyzed for three years in order to look at the relationships between seasonal turbidity trends, event...