Some natural ecosystems near industrialized and agricultural areas receive atmospheric nitrogen inputs that are an order of magnitude greater than those presumed for preindustrial times. Because (N) often limits microbial growth on dead vegetation, increased N input can be expected to affect the ecosystem process decomposition. We found extracellular enzyme responses a forest-floor community chronically applied aqueous NH4NO3 explain both decreased litter decomposition rates caused by added...

Because plant litter decomposition is directly mediated by extracellular enzymes (ectoenzymes), analyses of the dynamics their activity may clarify mechanisms that link rates to substrate quality and nutrient availability. We investigated this possibility placing arrays white birch sticks at eight upland, riparian, lotic sites on a forested watershed in northern New York. For 3 yr, samples were analyzed for mass loss, protein, total Kjeldahl nitrogen (TKN), phosphorus (TP) accumulation, 11...

The effects of “trace” (environmentally relevant) concentrations the antimicrobial agent sulfamethoxazole (SMX) on growth, nitrate reduction activity, and bacterial composition an enrichment culture prepared with groundwater from a pristine zone sandy drinking-water aquifer Cape Cod, MA, were assessed by laboratory incubations. When enrichments grown under heterotrophic denitrifying conditions exposed to SMX, noticeable differences control (no SMX) observed. Exposure SMX in as low 0.005 μM...

The fate and transport of inorganic nitrogen (N) is a critically important issue for human aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes lake on Cape Cod, MA. These factors included chemistry, seepage rates direction flow, the abundance potential activity N-cycling microbial communities. Genes coding...

Influenza A viruses (IAVs) deposited by wild birds into the environment may lead to sporadic mortality events and economically costly outbreaks among domestic birds. There is a paucity of information, however, regarding persistence infectious IAVs within following deposition. In this investigation, we assessed 12 that were present in cloacal and/or oropharyngeal swabs naturally infected ducks. Infectivity these was monitored over approximately one year with each virus tested five water...

Abstract Many freshwater lakes are groundwater flow‐through systems. Although commonly considered to be sinks for nitrogen inputs, relatively little is known about carbon and export from groundwater. The current study focused on lake‐bottom biogeochemical processes accompanying the transport of nitrogen, dissolved oxygen (O 2 ), organic (DOC) during lake‐water recharge a lake. Lake‐water porewater (15–100 cm below lakebed) samples were collected along transects within lake downwelling zone....

Abstract Microbial processing of atmospheric nitrogen (N) deposition regulates the retention and mobilization N in soils, with important implications for water quality. Understanding links between deposition, microbial communities, transformations, quality is critical as shifts toward reduced remains persistently high many regions. Here, we investigated these connections along an elevation transect Colorado Front Range. Although rates pools extractable increased down transect, soil...

Abstract As atmospheric dust deposition continues to increase across the southwestern United States, it has potential alter ecosystem productivity and structure by delivering nutrients, base cations, pollutants remote mountain sites. Due sparse distribution of monitoring sites, open questions remain about spatial temporal variability fluxes composition mountainous terrain. We present a 1 year (November 2017 November 2018) record seasonal from an elevation transect Colorado Front Range...

Abstract Urbanization can have substantial effects on water quality due to altered hydrology and introduction of constituents bodies. In arid semi‐arid environments, streams are further stressed by dewatering as a result diversions. We conducted high‐resolution synoptic survey two in Colorado, USA that transition abruptly from granitic/metamorphic forested mountains sedimentary urbanized plains both highly managed for supply, yet differ degree urbanization. A mass balance approach developed...

Abstract Information on the contribution of nitrogen (N)‐cycling processes in bed sediments to river nutrient fluxes large northern latitude systems is limited. This study examined relationship between N‐cycling and N speciation loading Yukon River near its mouth at Bering Sea. We conducted laboratory bioassays measure sediment samples collected over distinct water cycle seasons. In conjunction, microbial community composition using genes involved ( narG , napA nosZ amoA ) 16S rRNA gene...

Disposal of treated wastewater for more than 60 years onto infiltration beds on Cape Cod, Massachusetts produced a groundwater contaminant plume greater 6 km long in surficial sand and gravel aquifer. In December 1995 the disposal ceased. A long-term, continuous study was conducted to characterize post-cessation attenuation from source 0.6 downgradient. Concentrations total pools mobile constituents, such as boron nitrate, steadily decreased within 1−4 along transect. Dissolved organic...

Abstract As humans increasingly dominate the nitrogen cycle, deposition of reactive (Nr) will continue to have adverse consequences for ecosystems. In Rocky Mountains, Nr remains elevated and has become dominated by ammonium, despite efforts reduce emissions. Currently, spatial models do not fully account urban agricultural emissions, sources that contribute observed high rates ammonium in adjacent To address this gap Colorado Front Range, we measured along a transect from plains subalpine...

Abstract Groundwater discharge delivering anthropogenic N from surrounding watersheds can impact lake nutrient budgets. However, upgradient groundwater processes and changing dynamics in biogeochemistry at the groundwater‐lake interface are complex. In this study, seasonal water‐level variations a flow‐through altered patterns of wastewater‐derived contaminant plume, thereby affecting biogeochemical controlling transport. Pore water collected 15 cm under lakebed along transects perpendicular...

The use of wetlands as a treatment approach for nitrogen in runoff is common practice agroecosystems. However, nitrate not the sole constituent present agricultural and other biologically active contaminants have potential to affect removal efficiency. In this study, impacts combined effects four veterinary antibiotics (chlortetracycline, sulfamethazine, lincomycin, monensin) on nitrate-N efficiency saturated sediments were evaluated coupled microcosm/mesocosm scale experiment. Veterinary...

A plume of contaminated groundwater extends from former disposal beds at the Massachusetts Military Reservation's wastewater-treatment plant toward Ashumet Pond, coastal ponds, and Vineyard Sound, Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to rapid-infiltration for nearly 60 years before site moved a different location in December 1995. Water-quality samples were collected monitoring wells, multilevel samplers, profile borings characterize nature extent observe...

Water originating from coal-bed natural gas (CBNG) production wells typically contains ammonium and is often disposed via discharge to ephemeral channels. A study conducted in the Powder River Basin, Wyoming, documented downstream changes CBNG water composition, emphasizing nitrogen-cycling processes fate of ammonium. Dissolved concentrations 19 points ranged 95 527 μM. Within specific channels, decreased with transport distance, subsequent increases nitrite nitrate concentrations. Removal...