Nitrogen Cyclic in Forest and Grass Ecosystems Irrigated with 15 N-Enriched Wastewater

Jordan, Marilyn J.; Nadelhoffer, Knute J.; Fry, Brian

doi:10.2307/2269439

Cited by 25 publications

(38 citation statements)

References 24 publications

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“…Changes in abundance and composition of understory shrubs and herbs might also be expected in response to N deposition, as has been shown in Europe (Bobbink et al 1998). In the eastern United States the data are not as clear;the few studies that have examined this effect have used fertilization experiments as opposed to gradient studies or long-term measurements, and the studies have shown varying responses (Jordan et al 1997;Hurd et al 1998;Rainey et al 1999;Gilliam et al 2006). It is known from studies in the eastern United States that N addition shifts the activity of soil microorganisms, with some responding positively to N addition, while others respond negatively (e.g., Carreiro et al 2000).…”

Section: Forestsmentioning

confidence: 99%

Effects of Air Pollution on Ecosystems and Biological Diversity in the Eastern United States

Lovett

Tear

Evers

et al. 2009

Annals of the New York Academy of Sciences

194

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Conservation organizations have most often focused on land-use change, climate change, and invasive species as prime threats to biodiversity conservation. Although air pollution is an acknowledged widespread problem, it is rarely considered in conservation planning or management. In this synthesis, the state of scientific knowledge on the effects of air pollution on plants and animals in the Northeastern and Mid-Atlantic regions of the United States is summarized. Four air pollutants (sulfur, nitrogen, ozone, and mercury) and eight ecosystem types ranging from estuaries to alpine tundra are considered. Effects of air pollution were identified, with varying levels of certainty, in all the ecosystem types examined. None of these ecosystem types is free of the impacts of air pollution, and most are affected by multiple pollutants. In aquatic ecosystems, effects of acidity, nitrogen, and mercury on organisms and biogeochemical processes are well documented. Air pollution causes or contributes to acidification of lakes, eutrophication of estuaries and coastal waters, and mercury bioaccumulation in aquatic food webs. In terrestrial ecosystems, the effects of air pollution on biogeochemical cycling are also very well documented, but the effects on most organisms and the interaction of air pollution with other stressors are less well understood. Nevertheless, there is strong evidence for effects of nitrogen deposition on plants in grasslands, alpine areas, and bogs, and for nitrogen effects on forest mycorrhizae. Soil acidification is widespread in forest ecosystems across the eastern United States and is likely to affect the composition and function of forests in acid-sensitive areas over the long term. Ozone is known to cause reductions in photosynthesis in many terrestrial plant species. For the most part, the effects of these pollutants are chronic, not acute, at the exposure levels common in the eastern United States. Mortality is often observed only at experimentally elevated exposure levels or in combination with other stresses such as drought, freezing, or pathogens. The notable exceptions are the acid/aluminum effects on aquatic organisms, which can be lethal at levels of acidity observed in many surface waters in the region. Although the effects are often subtle, they are important to biological conservation. Changes in species composition caused by terrestrial or aquatic acidification or eutrophication can propagate throughout the food webs to affect many organisms beyond those that are directly sensitive to the pollution. Likewise, sublethal 100Annals of the New York Academy of Sciences doses of toxic pollutants may reduce the reproductive success of the affected organisms or make them more susceptible to potentially lethal pathogens. Many serious gaps in knowledge that warrant further research were identified. Among those gaps are the effects of acidification, ozone, and mercury on alpine systems, effects of nitrogen on species composition of forests, effects of mercury in terrestrial food webs, interactiv...

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Section: Forestsmentioning

confidence: 99%

Effects of Air Pollution on Ecosystems and Biological Diversity in the Eastern United States

Lovett

Tear

Evers

et al. 2009

Annals of the New York Academy of Sciences

194

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“…In the northwest region around the LWRP, nitrate isotope data confirm that the shallow wells here have a different nitrate source than in the rest of the study area (Figure 9). Shallow nitrate-δ 15 N values are between 13.0‰ and 29.2‰, in the range expected for treated wastewater effluent (Jordan et al, 1997;Griggs et al, 2003), and nitrate-δ…”

Section: Nitrate Sources Applied Wastewatermentioning

confidence: 78%

Nitrate Biogeochemistry and Reactive Transport in California Groundwater: LDRD Final Report

Esser¹,

Beller²,

Carle³

et al. 2006

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Introduction and BackgroundNitrate contamination is a significant threat to groundwater in California and other states. Successful groundwater management requires science-based simulation of future impacts in affected aquifers and science-based assessment of management practices designed to reduce nitrate levels. An important component of developing science-based approaches is the need to develop new and better tools for the characterization and quantification of biogeochemical reactions in the subsurface that control the fate and transport of nitrate in groundwater. When coupled with our ability to characterize groundwater flow and to model reactive transport, these new tools will allow an accurate assessment of the future distribution of nitrate in California aquifers and of the impact of different management practices on nitrate input to groundwater. Such assessment is vital to making cost-effective management and policy decisions regarding land use and groundwater remediation. Research ActivitiesOur research investigated the fate and transport of nitrate in groundwater at two scales, with an emphasis on microbial denitrification :• Field scale: denitrification in the shallow saturated zone at a dairy farm in the Central Valley, and • Basin scale: nitrate transport in two impacted basins.The research focused on developing and applying rapid methods to quantify denitrification in order to assess the role of denitrification in the shallow and deep saturated zone, and to allow quantitative assessment of the kinetics of microbiallymediated denitrification in groundwater systems.The research supported a number of students, including two LLNL postdocs.• Tracy LeTain, SEP, LLNL postdoc (Harry Beller, advisor) • Michael Singleton, CMS Directorate Postdoc (Bradley K. Esser advisor) -4-• Keara Moore, University of Arizona (Brenda Ekwurzel, advisor): Keara's work on nitrate source attribution and transport in the Livermore-Amador Basin formed the core of her M.S. thesis.• Brad Cey, University of Texas at Austin (Bridget Scanlon, advisor): Brad is using the dairy site that was developed with LDRD funding in his doctoral research.• Glenn Shaw, UC-Merced (Martha Conklin, advisor): Glenn participated in sampling at the dairy site, and spent a summer working at the lab. Technical accomplishments• We developed a quantitative polymerase chain reaction method for functional nitrite reductase genes to assay denitrifier populations in soil and in water; • We determined denitrification rate constants for an autotroph with Fe monosulfide; • We installed several multilevel wells and performed a synoptic water and soil survey at a Central Valley dairy that allowed us to demonstrate localized denitrification in stratified groundwater; • We used real-time qPCR to determine denitrifier populations in soil cores taken from the dairy wells, and demonstrated that denitrification was strongly localized at the oxic-anoxic interface at this site; • We developed a new tracer for manure lagoon seepage that allows us to distinguish wastewater ...

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“…At present, the 15 N trace technique has been proved useful as an tool for studying the ecological effects of N input on ecosystem. Jordan et al (1997) studied the N cycling in forest and grass ecosystems irrigated with 15 N-enriched wastewater in Falmouth, and found that under conditions of N saturation, δ 15 N values for plants were lower, possibly due to discrimination against 15 N during uptake of NH 4 + and NO 3 -by plant roots. Moreover, the capacity of soil N retention fell rapidly as the forest and grass ecosystems became N saturated, and N leaching losses greatly increased.…”

Section: Ecological Effects Of Nitrogen Input On Ecosystemmentioning

confidence: 99%

Application of stable isotope techniques in studies of carbon and nitrogen biogeochemical cycles of ecosystem

Sun

Mou

et al. 2011

Chin. Geogr. Sci.

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Stable isotope techniques have been proved useful as tools for studying the carbon (C) and nitrogen (N) biogeochemical cycles of ecosystem. This paper firstly introduced the basic principles and the distribution characteristics of stable isotope, then reviewed the recent advances and applications of stable isotope in the C and N biogeochemical cycles of ecosystem. By applying the 13 C natural abundance technique, ecologists are able to understand the photosynthetic path and CO 2 fixation of plants, the CO 2 exchange and C balance status of ecosystem, the composition, distribution and turnover of soil organic C and the sources of organic matter in food webs, while by using the 13 C labeled technique, the effects of elevated CO 2 on the C processes of ecosystem and the sources and fate of organic matter in ecosystem can be revealed in detail. Differently, by applying the 15 N natural abundance technique, ecologists are able to analyze the biological N 2 -fixation, the N sources of ecosystem, the N transformation processes of ecosystem and the N trophic status in food webs, while by using the 15 N labeled technique, the sources, transformation and fate of N in ecosystem and the effects of N input on the ecosystem can be investigated in depth. The applications of both C and N isotope natural abundance and labeled techniques, combined with the elemental, other isotope ( 34 S) and molecular biomarker information, will be more propitious to the investigation of C and N cycle mechanisms. Finally, this paper concluded the problems existed in current researches, and put forward the perspective of stable isotope techniques in the studies of C and N biogeochemical cycles of ecosystem in the future.

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Nitrogen Cyclic in Forest and Grass Ecosystems Irrigated with 15 N-Enriched Wastewater

Cited by 25 publications

References 24 publications

Effects of Air Pollution on Ecosystems and Biological Diversity in the Eastern United States

Effects of Air Pollution on Ecosystems and Biological Diversity in the Eastern United States

Nitrate Biogeochemistry and Reactive Transport in California Groundwater: LDRD Final Report

Application of stable isotope techniques in studies of carbon and nitrogen biogeochemical cycles of ecosystem

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