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Carter TS, Clark CM, Fenn ME, Jovan S, Perakis SS, Riddell J, Schaberg PG, Greaver TL, Hastings MG. Mechanisms of nitrogen deposition effects on temperate forest lichens and trees. Ecosphere 2017; 8:10.1002/ecs2.1717. [PMID: 34327038 PMCID: PMC8318115 DOI: 10.1002/ecs2.1717] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We review the mechanisms of deleterious nitrogen (N) deposition impacts on temperate forests, with a particular focus on trees and lichens. Elevated anthropogenic N deposition to forests has varied effects on individual organisms depending on characteristics both of the N inputs (form, timing, amount) and of the organisms (ecology, physiology) involved. Improved mechanistic knowledge of these effects can aid in developing robust predictions of how organisms respond to either increases or decreases in N deposition. Rising N levels affect forests in micro- and macroscopic ways from physiological responses at the cellular, tissue, and organism levels to influencing individual species and entire communities and ecosystems. A synthesis of these processes forms the basis for the overarching themes of this paper, which focuses on N effects at different levels of biological organization in temperate forests. For lichens, the mechanisms of direct effects of N are relatively well known at cellular, organismal, and community levels, though interactions of N with other stressors merit further research. For trees, effects of N deposition are better understood for N as an acidifying agent than as a nutrient; in both cases, the impacts can reflect direct effects on short time scales and indirect effects mediated through long-term soil and belowground changes. There are many gaps on fundamental N use and cycling in ecosystems, and we highlight the most critical gaps for understanding potential deleterious effects of N deposition. For lichens, these gaps include both how N affects specific metabolic pathways and how N is metabolized. For trees, these gaps include understanding the direct effects of N deposition onto forest canopies, the sensitivity of different tree species and mycorrhizal symbionts to N, the influence of soil properties, and the reversibility of N and acidification effects on plants and soils. Continued study of how these N response mechanisms interact with one another, and with other dimensions of global change, remains essential for predicting ongoing changes in lichen and tree populations across North American temperate forests.
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Affiliation(s)
- Therese S. Carter
- US Global Change Research Program, ICF Contractor, 1800 G Street NW, Suite 9100, Washington, D.C. 20006 USA
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912 USA
| | - Christopher M. Clark
- US EPA, Office of Research and Development, Global Change Research Group, 1200 Pennsylvania Avenue, N. W., Washington, D.C. 20460 USA
| | - Mark E. Fenn
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, California 92507 USA
| | - Sarah Jovan
- USDA Forest Service, Pacific Northwest Research Station, 620 SW Main Street, Portland, Oregon 97205 USA
| | - Steven S. Perakis
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, Oregon 97331 USA
| | - Jennifer Riddell
- Sustainable Technology Program, Mendocino College, 1000 Hensley Creek Road, Ukiah, California 95482 USA
| | - Paul G. Schaberg
- USDA Forest Service, Northern Research Station, 705 Spear Street S, Burlington, Vermont 05405 USA
| | - Tara L. Greaver
- National Center for Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711 USA
| | - Meredith G. Hastings
- Department of Earth, Environmental, and Planetary Sciences, Institute at Brown for Environment and Society, Brown University, 324 Brook Street, Providence, Rhode Island 02912 USA
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Yu L, Belyazid S, Akselsson C, van der Heijden G, Zanchi G. Storm disturbances in a Swedish forest—A case study comparing monitoring and modelling. Ecol Modell 2016. [DOI: 10.1016/j.ecolmodel.2015.09.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Erlandsson M, Laudon H, Fölster J. Spatiotemporal patterns of drivers of episodic acidification in Swedish streams and their relationships to hydrometeorological factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:4633-4643. [PMID: 20637494 DOI: 10.1016/j.scitotenv.2010.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 06/07/2010] [Accepted: 06/09/2010] [Indexed: 05/29/2023]
Abstract
This study examined the spatiotemporal patterns of episodic acidification in 87 weakly buffered streams in Sweden at a monthly sampling frequency during a ten-year study period (1998-2007). Time series of pre-industrial pH (pH(0)) were reconstructed from the acidification model Meta(MAGIC), and the acidification impact was defined by the difference between the pH(0) and the contemporary pH (i.e., DeltapH=pH(0)-pH(t)). Acidification episodes were defined as observations for which the pH(t) was at least 0.4 units lower than average, in combination with a pH at least 0.2 units higher than average. Thus, only occasions in which the stream water was both more acidic and more acidified than average were characterized as acidification episodes. For each observed episode, the primary cause was identified from one of the following five possible drivers: dilution, increase in sulfate, nitrate or organic acids, or sea salt deposition. In total, 258 episodes were observed during the study period. The study showed that streams that were acidified during baseflow (DeltapH>0.4), but not chronically acidic (pH>5.2), were subjected to regular episodic acidification. Dilution was the single most important cause and the main driver for 58% of the identified episodes. Increases in sulfate concentrations were also relatively common (26% of episodes), whereas increases in nitrate and organic acids as well as sea salt deposition were of minor importance. The total number of dilution-related acidification episodes within a year had a significant (p=0.005) positive correlation (r=+0.83) with the average annual precipitation. Occurrences of sulfate episodes were related to droughts during the preceding summers. While the number of streams that are susceptible to episodic acidification will decrease as a consequence of recovery from acidification, the hydrological and meteorological consequences of future climate change may make episodic acidification more common.
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Affiliation(s)
- Martin Erlandsson
- Department of Environmental Assessment, Swedish University of Agricultural Sciences, Box 7050, 750 07, Uppsala, Sweden.
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Aherne J, Larssen T, Cosby BJ, Dillon PJ. Climate variability and forecasting surface water recovery from acidification: modelling drought-induced sulphate release from wetlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2006; 365:186-99. [PMID: 16616319 DOI: 10.1016/j.scitotenv.2006.02.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Climate-induced drought events have been shown to have a significant influence on sulphate (SO(4)(2-)) export from forested catchments in central Ontario, subsequently delaying recovery of surface waters from acidification. Field and modelling studies have demonstrated that water table drawdown during drought periods promotes oxidation of previously stored (reduced) sulphur (S) compounds in wetlands, with subsequent efflux of SO(4)(2-) upon re-wetting. Although climate-induced changes in processes are generally not integrated into soil-acidification models, MAGIC (Model of Acidification of Groundwater in Catchments) includes a wetland compartment that incorporates redox processes driven by drought events. The potential confounding influence of climate-induced drought events on acidification recovery at Plastic Lake, south-central Ontario (under proposed future S emission reductions) was investigated using MAGIC and two climate scenarios: monthly precipitation and runoff based on long-term means (average-climate scenario), and variable precipitation and runoff based on the past 20 years of observed monthly data (variable-climate scenario). The variable-climate scenario included several periods of summer drought owing to lower than average rainfall and higher then average temperature. Nonetheless, long-term regional trends in precipitation and temperature suggest that the variable-climate scenario may be a conservative estimate of future climate. The average-climate scenario indicated good recovery potential with acid neutralising capacity (ANC) reaching approximately 40 micromol(c)L(-1) by 2020 and 50 micromol(c)L(-1) by 2080. In contrast, the forecasted recovery potential under the variable-climate scenario was very much reduced. By 2080, ANC was forecasted to increase to 2.6 micromol(c)L(-1) from -10.0 micromol(c)L(-1) in 2000. Elevated SO(4)(2-) efflux following drought events (introduced under the variable-climate scenario) has a dramatic impact on simulated future surface water chemistry. The results clearly demonstrate that prediction of future water quality, using models such as MAGIC, should take into account changes or variability in climate as well as acid deposition.
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Affiliation(s)
- J Aherne
- Department of Environmental and Resource Studies, Trent University, Peterborough, Ontario, Canada.
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Larssen T. Model prognoses for future acidification recovery of surface waters in norway using long-term monitoring data. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:7970-9. [PMID: 16295863 DOI: 10.1021/es0484247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
During the past 20 years, acid deposition in Europe has decreased by more than 60%, yet still a large number of lakes and streams in southern Norway have not recovered to a water quality sufficient to support sustainable populations of trout or salmon. Long-term (30 years) monitoring data were used hereto constrain the calibration of the acidification model MAGIC to three Norwegian calibrated catchments. The model accounted for 60-80% of the variance in the year-to-year variations in concentrations of most of the major ions in streamwater. The results support the use of the lumped parameter acid neutralizing capacity (ANC) to link chemical parameters to biological response, as the calibration efficiency for ANC is considerably higher than for other biologically important parameters such as inorganic aluminum (Al(n+)) and pH. Three different scenarios for future deposition of sulfur were run: current legislation, maximum feasible reductions, and an illustrative scenario removing all anthropogenic deposition. These analyses show that much of the potential improvement in water quality has already occurred and that only limited further improvement can be expected from the current legislation. The current legislation is unlikely to produce ANC values sufficiently high to allow self-reproducing populations of trout at two of the three sites. Most of the response in water chemistry to reduced acid deposition has been rapid; the water chemical responses largely occur the same year or a few years after reduction in the input. The soil pool of exchangeable base cations depleted during 150 years of acid deposition, however, requires several centuries for replenishment. The uncertainties in future predictions come from several factors, such as future nitrogen dynamics and impacts from changes in seasalt and precipitation events. The differences in future water chemistry predicted from changed seasalt deposition or nitrogen dynamics are larger that the differences between different deposition scenarios. Hence, these factors must be included in future assessments of recovery from acidification.
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Affiliation(s)
- Thorjørn Larssen
- Norwegian Institute for Water Research (NIVA), Post Office Box 173, Oslo, Norway.
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