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Water quality and optical absorbance data for journal article entitled, "The removal kinetics of dissolved organic matter and the optical clarity of groundwater" by Francis H. Chapelle, Yuan Shen, Eric W. Strom, and Ronald Benner. Hydrogeology Journal. In Press.
It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies have been conducted in these environments. We conducted a landscape scale study examining Hg cycling in coastal Louisiana (USA) including four field trips conducted between August 2003 and May 2005. Sites were chosen to represent different ecosystem types, including: a large shallow eutrophic estuarine lake (Lake Pontchartrain), three rivers draining...
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These replicate data support the findings described in the publication, "A comparison of four pore water sampling methods for mixed metals and dissolved organic carbon, and implications for sediment toxicity evaluations" by Danielle Cleveland, William G. Brumbaugh, and Donald D. MacDonald (Environmental Toxicology and Chemistry 2017). The data represent comparison of four commonly-applied techniques for obtaining pore water samples for the quantification of nickel, copper, zinc, arsenic, cadmium, lead and dissolved organic carbon (DOC), including peepers, push points, centrifugation, and diffusive gradients in thin films (DGTs). The methods were evaluated at low and high concentrations of metals in three sediments...
Mercury (Hg) was measured in stream water and precipitation in the Loch Vale watershed in Rocky Mountain National Park, Colorado, during 2001–2002 to investigate processes controlling Hg transport in high-elevation ecosystems. Total Hg concentrations in precipitation ranged from 2.6 to 36.2 ng/L and showed a strong seasonal pattern with concentrations that were 3 to 4 times higher during summer months. Annual bulk deposition of Hg was 8.3 to 12.4 μ g/m2 and was similar to deposition rates in the Midwestern and Northeastern U.S. Total Hg concentrations in streams ranged from 0.8 to 13.5 ng/L and were highest in mid-May on the rising limb of the snowmelt hydrograph. Stream-water Hg was positively correlated with dissolved...
Spatial patterns in carbon (C) and nitrogen (N) cycles of high-latitude catchments have been linked to climate and permafrost, and used to infer potential changes in biogeochemical cycles under climate warming. However, inconsistent spatial patterns across regions indicate that factors in addition to permafrost and regional climate may shape responses of C and N cycles to climate change. We hypothesized that physical attributes of catchments modify responses of C and N cycles to climate and permafrost. We measured dissolved organic C (DOC) and nitrate (NO3–) concentrations, and composition of dissolved organic matter (DOM) in 21 streams spanning boreal to arctic Alaska, and assessed permafrost, topography, and attributes...
Mercury (Hg) was measured in stream water and precipitation in the Loch Vale watershed in Rocky Mountain National Park, Colorado, during 2001–2002 to investigate processes controlling Hg transport in high-elevation ecosystems. Total Hg concentrations in precipitation ranged from 2.6 to 36.2 ng/L and showed a strong seasonal pattern with concentrations that were 3 to 4 times higher during summer months. Annual bulk deposition of Hg was 8.3 to 12.4 μ g/m2 and was similar to deposition rates in the Midwestern and Northeastern U.S. Total Hg concentrations in streams ranged from 0.8 to 13.5 ng/L and were highest in mid-May on the rising limb of the snowmelt hydrograph. Stream-water Hg was positively correlated...
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Groundwater data were collected in the spring and fall of 2008 from three sites representing different geological settings and biogeochemical conditions within the surficial glacial aquifer of Long Island, NY. Investigations were designed to examine the extent to which average vadose zone thickness in contributing watersheds controlled biogeochemical conditions and processes, including dissolved oxygen concentration (DO), oxidation-reduction potential (Eh), dissolved organic carbon concentration (DOC), and microbial dinitrogen (N2) production. Greatest N2 production was observed at the south shore of Long Island, which is characterized by a thin vadose zone, low DO and Eh, and relatively high DOC. Limited N2 production...
Roots influence root litter decomposition through multiple belowground processes. Hydraulic lift or redistribution (HR) by plants is one such process that creates diel drying?rewetting cycles in soil. However, it is unclear if this phenomenon influences decomposition. Since decomposition in deserts is constrained by low soil moisture and is stimulated when dry soils are rewetted, we hypothesized that diel drying?rewetting, via HR, stimulates decomposition of root litter. We quantified the decomposition of root litter from two desert shrubs, Artemisia tridentata ssp. tridentata and Sarcobatus vermiculatus, during spring and summer in field soil core treatments designed to have abundant roots and high magnitude HR...
Spatial patterns in carbon (C) and nitrogen (N) cycles of high-latitude catchments have been linked to climate and permafrost, and used to infer potential changes in biogeochemical cycles under climate warming. However, inconsistent spatial patterns across regions indicate that factors in addition to permafrost and regional climate may shape responses of C and N cycles to climate change. We hypothesized that physical attributes of catchments modify responses of C and N cycles to climate and permafrost. We measured dissolved organic C (DOC) and nitrate (NO3–) concentrations, and composition of dissolved organic matter (DOM) in 21 streams spanning boreal to arctic Alaska, and assessed permafrost, topography, and attributes...
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Data includes fine‑scale (1.5 cm minimum resolution) vertical solute concentrations for filtered methylmercury (ng/L), filtered total mercury (ng/L), dissolved organic carbon (mg/L), and dissolved chloride (micromole/L) in SixMile Brook, New York and McTier Creek, South Carolina. Vertical solute data were assessed one time at one site in each stream in 2009, at edge-of-water (margin) and center-of-channel (channel) using two mini-piezometer (USGS MINIPOINT) devices (seven 0.325 cm stainless steel tubes, 0.8 cm screened interval). Each MINIPOINT device was installed with sampling points in surface water and at approximately 1.5, 4.5, 7.5, 12.5, 17.5, 30, and 60 cm below the bed-sediment/surface water interface.
Stream water samples were collected over a range of hydrologic and seasonal conditions at three forested watersheds in the northeastern USA. Samples were analyzed for dissolved total mercury (THgd), DOC concentration and DOC composition, and UV254 absorbance across the three sites over different seasons and flow conditions. Pooling data from all sites, we found a strong positive correlation of THgd to DOC (r2 = 0.87), but progressively stronger correlations of THgd with the hydrophobic acid fraction (HPOA) of DOC (r2 = 0.91) and with UV254 absorbance (r2 = 0.92). The strength of the UV254 absorbance–THgd relationship suggests that optical properties associated with dissolved organic matter may be excellent proxies...
It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies have been conducted in these environments. We conducted a landscape scale study examining Hg cycling in coastal Louisiana (USA) including four field trips conducted between August 2003 and May 2005. Sites were chosen to represent different ecosystem types, including: a large shallow eutrophic estuarine lake (Lake Pontchartrain), three rivers draining...
The effects of a dry-rewetting event (D/RW) on soil microbial properties and nutrient release by leaching from two soils taken from adjacent grasslands with different histories of management intensity were studied. These were a low-productivity grassland, with no history of fertilizer application and a high-productivity grassland with a history of high fertilizer application, referred to as unimproved and improved grassland, respectively. The use of phospholipid fatty acid analysis (PLFA) revealed that the soil of the unimproved grassland had a significantly greater microbial biomass, and a greater abundance of fungi relative to bacteria than did the improved grassland. Soils from both grasslands were maintained...
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Conclusions: The proportion of wetlands in the watershed at different scales affects dissolved organic carbon (DOC) concentrations in downstream lakes and rivers. Thresholds/Learnings: Synopsis: This study quantifies how the proportion of wetlands in the watershed at different scales affects dissolved organic carbon (DOC) concentrations in downstream lakes and rivers. Whether the watershed influence varies with season or hydrologic type of lake was also examined. The scaling and modelling approach used offered a useful way to examine heterogeneity of land cover types within the watershed and spatial arrangements, while allowing generality of conclusions with a large sample size. Zones of increasing distance from...
    map background search result map search result map Landscape indictors of human impacts to riverine systems Water quality and optical absorbance data for groundwater samples collected during 2010 to 2012 from select Principal Aquifers of the United States Vertical gradients of filtered methylmercury, filtered total mercury, dissolved organic carbon, and dissolved chloride in stream-bed sediments at SixMile Brook, New York and McTier Creek, South Carolina during summer 2009 A comparison of four pore water sampling methods for mixed metals and dissolved organic carbon, and implications for sediment toxicity evaluations-Data Coastal Groundwater Chemical Data from the North and South Shores of Long Island, New York A comparison of four pore water sampling methods for mixed metals and dissolved organic carbon, and implications for sediment toxicity evaluations-Data Vertical gradients of filtered methylmercury, filtered total mercury, dissolved organic carbon, and dissolved chloride in stream-bed sediments at SixMile Brook, New York and McTier Creek, South Carolina during summer 2009 Water quality and optical absorbance data for groundwater samples collected during 2010 to 2012 from select Principal Aquifers of the United States Landscape indictors of human impacts to riverine systems