Progress 08/15/05 to 08/14/10
Outputs
OUTPUTS: Depletion of labile calcium (Ca) pools in soil by acid rain has increased interest in soil Ca dynamics. Previous work that microbial C and N cycle processes are unresponsive to Ca additions and pH increases of 0.5 - 1.0 units. We established 20 5 x 5 m field plots and plant-free mesocosms with 4 treatments; Ca fertilization (850 or 4,250 kg/ha) as wollastonite, P (50 kg/ha) as NaPO4 and (P + 850 kg/ha Ca) to test three hypotheses; 1) Microbial biomass and activity are not controlled by soil pH in northern hardwood forest soils. We tested this hypothesis by quantifying the pH optima for microbial processes in Ca treated and reference soils; 2) the ability of microbes to respond to increased soil pH is limited by P availability, and 3) Ca additions inhibit microbial access to labile carbon. We tested this hypothesis with lab studies of Ca-C-microbial interactions, characterization of labile C using nuclear magnetic resonance (NMR) spectroscopy, and measurements of gross mineralization and nitrification. We observed increases in nitrification in response to Ca additions in plant-free mesocosms, but not in field plots. These results suggest that plants inhibit nitrifier response to Ca additions by uptake of ammonium. pH optima experiments showed that raising soil pH above 4 increases mineralization and nitrification, but rates did not increase as pH was raised to 5 and 6. Gross N mineralization did not respond to either low or high Ca additions. However, high Ca addition increased microbial N immobilization and this substantially reduced short-term net N mineralization. We observed P-limitation of nitrification, with gross nitrification increasing more than 2x in response to P addition. High rates of microbial N immobilization appeared to consume the nitrate so that no net response was seen. Other field and lab results showed no microbial responses to P additions. However, P plus Ca reduced short-term (2 d) gross and net N mineralization, indicating that some combination of P and Ca altered microbial N transformations. Results from C-addition experiments showed that Ca availability reduces long-term mineralization of soil organic C but not that of added leaf litter. Mineralization of added litter was reduced, however, by further Ca addition in the lab. Chemical characterization of soil organic matter (SOM) work focused on hot-water extractable organic matter (HWEOM), a bioavailable fraction of the SOM. We investigated the effect of Ca-treatment on SOM and HWEOM in the forest floor with the hypothesis that applied Ca binds with labile organic fractions of SOM leaving them unavailable to soil microbes. We found a net decrease in hot-water extractable organic carbon in Ca-treated plots compared to control plots. We also found an increase in soil C/N ratio with time for Ca-treated plots, suggesting that microbial activity was suppressed. NMR spectroscopic results confirmed that the organic carbon present as O-alkyl functional groups has decreased with Ca-treatment in HWEOM. The rate of biodegradation of HWEOM extracted from Ca-treated soils was not significantly different suggesting that the Ca treatment did not reduce bioavailability of soil C. PARTICIPANTS: Peter Groffman, principal investigator Melany Fisk, principal investigator Chris Johnson, principal investigator Ankit Balaria, graduate student Kevan Minick, graduate student Lisa Martel, technician David Lewis, technician Robin Schmidt, technician TARGET AUDIENCES: The target audience for this research is primarily scientific; forest soil scientists, ecologists and soil microbial ecologists. However, results from this project have relevance to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics is important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to producing publications for scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policymakers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from this project are relevant to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics is important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to publications in scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policymakers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material.
Publications
- Balaria, A., Johnson, C.E., and Xu, Z. 2008. Molecular-scale characterization of hot-water extractable organic matter in organic horizons of a forest soil. Soil Science Society of America Journal 73:812-821.
- Groffman, P.M. and M.C. Fisk. 2011. Calcium contrains plant control over forest ecosystem nitrogen cycling. Submitted to Proceedings of the National Academies of Science.
- Minick, K.J., Fisk, M.C. and P.M. Groffman. 2010. Calcium and phosphorus interact to reduce mid-growing season net nitrogen mineralization potential in organic horizons in a northern hardwood forest. Soil Biology and Biochemistry doi:10.1016/j.soilbio.2010.10.009.
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Progress 08/15/08 to 08/14/09
Outputs
OUTPUTS: Depletion of labile calcium (Ca) pools in soil by acid rain has increased interest in soil Ca dynamics. Previous work that microbial C and N cycle processes are unresponsive to Ca additions and pH increases of 0.5 - 1.0 units. We established 20 5 x 5 m field plots and plant-free mesocosms with 4 treatments; Ca fertilization (850 or 4,250 kg/ha) as wollastonite, P (50 kg/ha) as NaPO4 and (P + 850 kg/ha Ca) to test three hypotheses; 1) Microbial biomass and activity are not controlled by soil pH in northern hardwood forest soils. We tested this hypothesis by quantifying the pH optima for microbial processes in Ca treated and reference soils; 2) the ability of microbes to respond to increased soil pH is limited by P availability, and 3) Ca additions inhibit microbial access to labile carbon. We tested this hypothesis with lab studies of Ca-C-microbial interactions, characterization of labile C using nuclear magnetic resonance (NMR) spectroscopy, and measurements of gross mineralization and nitrification. We observed increases in nitrification in response to Ca additions in plant-free mesocosms, but not in field plots. These results suggest that plants inhibit nitrifier response to Ca additions by uptake of ammonium. pH optima experiments showed that raising soil pH above 4 increases in mineralization and nitrification, but trates do not increase as pH is raised to 5 and 6. Gross N mineralization did not respond to either low or high Ca additions. However, high Ca addition increased microbial N immobilization and this substantially reduced short-term net N mineralization. We observed strong P-limitation of nitrification, with gross nitrification increasing more than 2x in response to P addition. High rates of microbial N immobilization appear to consume the nitrate so that no net response is seen. Other field and lab results show no microbial responses to P additions. However, P plus Ca reduced short-term (2 d) gross and net N mineralization, indicating that some combination of P and Ca alters microbial N transformations. Results from C-addition experiments show that Ca availability reduces long-term mineralization of soil organic C but not that of added leaf litter. Mineralization of added litter was reduced, however, by further Ca addition in the lab. Chemical characterization of soil organic matter (SOM) work has focused on hot-water extractable organic matter (HWEOM), a bioavailable fraction of the SOM. We investigated the effect of Ca-treatment on SOM and HWEOM in the forest floor with the hypothesis that applied Ca binds with labile organic fractions of SOM leaving them unavailable to soil microbes. We found a net decrease in hot-water extractable organic carbon in Ca-treated plots compared to control plots. We also found an increase in soil C/N ratio with time for Ca-treated plots, suggesting that microbial activity is suppressed. NMR spectroscopic results confirmed that the organic carbon present as O-alkyl functional groups has decreased with Ca-treatment in HWEOM. Continuing analysis will determine the rate of biodegradation, and amount of organic components (e.g. carbohydrates, proteins, lipids, etc.) using a molecular mixing model. PARTICIPANTS: Peter Groffman, principal investigator Melany Fisk, principal investigator Chris Johnson, principal investigator Ankit Balaria, graduate student Kevan Minick, graduate student Lisa Martel, technician David Lewis, technician Robin Schmidt, technician TARGET AUDIENCES: The target audience for this research is primarily scientific; forest soil scientists, ecologists and soil microbial ecologists. However, results from this project will have relevance to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics will be important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to producing publications for scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policymakers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from this project will have relevance to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics will be important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to producing publications for scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policymakers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material.
Publications
- Balaria, A., Johnson, C.E., and Xu, Z. 2008. Molecular-scale characterization of hot-water extractable organic matter in organic horizons of a forest soil. Soil Science Society of America Journal 73:812-821.
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Progress 08/15/07 to 08/14/08
Outputs
OUTPUTS: Depletion of labile calcium (Ca) pools in soil by acid rain has increased interest in soil Ca dynamics. Previous work found the surprising result that microbial C and N cycle processes are unresponsive to Ca additions and increases in soil pH of 0.5 - 1.0 units. In this project we established 20 5 x 5 m field plots and plant-free mesocosms with 4 treatments; fertilization with Ca (850 or 4,250 kg/ha) as wollastonite, P (50 kg/ha) as NaPO4 and (P + 850 kg/ha Ca) to test three hypotheses to explain these results; 1) Microbial biomass and activity are not strongly controlled by soil pH in northern hardwood forest soils. We tested this hypothesis by quantifying the pH optima for microbial processes in Ca treated and reference soils; 2) the ability of microbes to respond to increased soil pH is limited by P availability. We are testing this with our fertilization experiments and; 3) Ca additions inhibit microbial access to labile carbon. We are testing this hypothesis with laboratory studies of Ca-C-microbial interactions, characterization of labile C using nuclear magnetic resonance (NMR) spectroscopy, and measurements of gross mineralization and nitrification and microbial biomass and community structure. We observed increases in nitrification in response to Ca additions in plant-free mesocosms, but not in field plots. These results suggest that plants are either inhibiting (by uptake of ammonium) or masking (by taking up nitrate) microbial response to the Ca additions. Measurements of gross rates of mineralization and nitrification and analysis of pH optima experiments will clarify which mechanism is important. Results from both field and laboratory plots have shown no response of any microbial process to P additions, suggesting that hypothesis #2 can be rejected. However, an interesting interaction of P and Ca caused a reduction in short-term (2 d) net N relative to C mineralization. These results suggest that the combination of P and Ca availability increase N immobilization. Results from C-addition experiments show that Ca availability alters the time-course of mineralization of added C. Ca availability suppressed mineralization of added acetate over the short term (2 wk). In contrast, Ca availability increased long-term (9 wk) mineralization of added leaf litter C. Our chemical characterization of soil organic matter (SOM) work has focused on hot-water extractable organic matter (HWEOM), a bioavailable fraction of the SOM. NMR analysis has shown that HWEOM has significantly lower C:N ratio, higher H:C ratio and higher O-alkyl C content than whole soil. The fraction of O-alkyl C in HWEOM increases with soil depth, while alkyl C decreases, contrary to the pattern observed for the whole soil. The NMR properties and elemental composition of HWEOM support the hypothesis that HWEOM is largely a mixture of carbohydrates and proteins that includes both labile C fractions and microbial biomass. Continuing analysis will determine if the amount or composition of HWEOM is affected by Ca and/or P addition. We are also using a molecular mixing model in an attempt to better estimate the biomolecular composition of both SOM and HWEOM. PARTICIPANTS: Peter Groffman, principal investigator Melany Fisk, principal investigator Chris Johnson, principal investigator Ankit Balaria, graduate student Kevan Minick, graduate student Lisa Martel, technician David Lewis, technician Robin Schmidt, technician TARGET AUDIENCES: The target audience for this research is primarily scientific; forest soil scientists, ecologists and soil microbial ecologists. However, results from this project will have relevance to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics will be important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to producing publications for scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policy-makers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from this project will have relevance to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics will be important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to producing publications for scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policy-makers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material.
Publications
- Balaria, A., Johnson, C.E., and Xu, Z. 2008. Molecular-scale characterization of hot-water extractable organic matter in organic horizons of a forest soil. Soil Science Society of America Journal. In press.
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Progress 08/15/06 to 08/14/07
Outputs
Concern about the role of acidic deposition in the long-term depletion of Ca in soil and vegetation led to the initiation of a watershed-scale Ca addition experiment at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire in 1999 (www.hubbardbrook.org). We treated an 11.8 ha watershed (watershed 1) with a Ca-silicate mineral (wollastonite) to restore the Ca that we estimate was leached from the ecosystem by 50 years of acidic deposition. The 1999 addition (850 kg/ha) was designed to increase the base saturation of watershed soils from approximately 10% to 19% (the modeled pre-acid rain value) and has resulted in marked changes in streamwater and soil pH and vegetation Ca dynamics. The addition and basic monitoring of changes in watershed processes were funded by a grant from the National Science Foundation (NSF). This project builds on the existing Ca addition study in watershed 1 at the HBEF. We established new fertilization plots and laboratory mesocosms to
test three hypotheses (listed below). We have 20 new 5 m x 5 m plots; five replicates of four treatments involving fertilization with Ca (850 or 4,250 kg/ha) as wollastonite, P (50 kg/ha) as NaPO4 and (P + 850 kg/ha Ca). These plots are instrumented with permanent trace gas flux monitoring chamber bases and tension lysimeters installed just below the Oa horizon. We also set up plant-free mesocosms (bins of soil collected and homogenized from the Oie, Oa and mineral horizons and held at room temperature and field capacity moisture content) with the same treatments (Ca (850 and 10,000 kg/ha), P, Ca + P) so that we can assess microbial processes in the absence of plants. We are using these plots to test three hypotheses; 1) Microbial biomass and activity are not strongly controlled by soil pH in northern hardwood forest soils. We will test this hypothesis by quantifying the pH optima for a series of microbial C and N cycle processes in Ca treated and reference soils in summer 2008; 2)
the ability of microbes to respond to increased soil pH is limited by phosphorus availability. Soil microbial activity at the HBEF may be limited by phosphorus and therefore cannot respond to the pH effect induced by Ca additions as a result. We will test this hypothesis by assessing response to our field and laboratory fertilization experiments and; 3) Ca additions inhibit microbial access to labile carbon. Recent studies suggest that Ca ions may have the ability to chemically bind labile C, limiting microbial access to C and leading to inhibition of microbial activity and growth. We will test this hypothesis with laboratory studies of Ca-C-microbial interactions, characterization of labile C using nuclear magnetic resonance (NMR) spectroscopy, and measurements of gross mineralization and nitrification and microbial biomass and community structure (PLFA). Plots were established and instrumented in summer 2006 and routine monitoring of soil microbial biomass and activity, soil
solution chemistry and soil:atmosphere trace gas fluxes began in fall 2006.
Impacts
Results from this project will have relevance to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics will be important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to producing publications for scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives
linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policy-makers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material.
Publications
- Groffman, P.M., M.C. Fisk, C.T. Driscoll, G.E. Likens, T.J. Fahey, C. Eagar and L.H. Pardo. 2006. Calcium additions reduce nitrogen cycling in a northern hardwood forest. Ecosystems 9:1289-1305.
- Groffman, P, C. Johnson and M.C. Fisk. 2006. Microbial Biomass and Activity in Acid Forest Soils Amended with Wollastonite (CaSiO3). Annual Meeting of the Soil Science Society of America. November 2006. Indianapolis, IN.
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Progress 08/15/05 to 08/14/06
Outputs
Concern about the role of acidic deposition in the long-term depletion of Ca in soil and vegetation led to the initiation of a watershed-scale Ca addition experiment at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire in 1999 (www.hubbardbrook.org). We treated an 11.8 ha watershed (watershed 1) with a Ca-silicate mineral (wollastonite) to restore the Ca that we estimate was leached from the ecosystem by 50 years of acidic deposition. The 1999 addition (850 kg/ha) was designed to increase the base saturation of watershed soils from approximately 10% to 19% (the modeled pre-acid rain value) and has resulted in marked changes (detailed below) in streamwater and soil pH and vegetation Ca dynamics. The addition and basic monitoring of changes in watershed processes were funded by a grant from the National Science Foundation (NSF). This project builds on, the existing Ca addition study in watershed 1 at the HBEF. During this first year of work, we have
established new, small fertilization plots and laboratory mesocosms to test three hypotheses (listed below). We have established 20 new 5 m x 5 m plots; five replicates of four treatments involving fertilization with Ca (850 or 4,250 kg/ha) as wollastonite, P (50 kg/ha) as NaPO4 and (P + 850 kg/ha Ca). These plots are instrumented with permanent trace gas flux monitoring chamber bases and tension lysimeters installed just below the Oa horizon. Later this summer, we will collect and homogenize large amounts of soil (ca. 100 kg) from the Oie, Oa and mineral horizons and set up plant-free mesocosms (bins of soil held at room temperature and field capacity moisture content) with the same treatments (Ca (850 and 10,000 kg/ha), P, Ca + P) so that we can assess microbial processes in the absence of plants. We will use these plots to test three hypotheses; 1) Microbial biomass and activity are not strongly controlled by soil pH in northern hardwood forest soils. Long-term exposure to low pH
has led to the development of microbial communities that are adapted to acidic conditions and that do not respond in a positive way to increases in soil pH. We will test this hypothesis by quantifying the pH optima for a series of microbial C and N cycle processes in Ca treated and reference soils; 2) the ability of microbes to respond to increased soil pH is limited by phosphorus availability. Soil microbial activity at the HBEF may be limited by phosphorus and microbial biomass and activity cannot respond to the pH effect induced by Ca additions as a result. We will test this hypothesis with field and laboratory fertilization experiments and measurements of phosphatase activity and; 3) Ca additions inhibit microbial access to labile carbon. Recent studies suggest that Ca ions may have the ability to chemically bind labile C, limiting microbial access to C and leading to inhibition of microbial activity and growth. We will test this hypothesis with laboratory studies of
Ca-C-microbial interactions, characterization of labile C using nuclear magnetic resonance (NMR) spectroscopy, and measurements of gross mineralization and nitrification and microbial biomass and community structure (PLFA).
Impacts
Results from this project will have relevance to forest production over the northeastern region of the U.S. Loss of calcium (Ca) may be a key factor limiting carbon (C ) and nitrogen (N) sequestration in forests this region, and there are active efforts to consider amendments to the Clean Air Act to reduce deposition and/or to make applications of Ca to acid-damaged forests. Understanding interactions between Ca, N and C dynamics will be important to evaluating the productivity, C sequestration and water quality implications of these efforts. In addition to producing publications for scientific journals, results from this project will become part of the education and outreach program of the Hubbard Brook Ecosystem Study. Results will be disseminated through the Hubbard Brook website (http://www.hubbardbrook.org) and by the Hubbard Brook Research Foundation (HBRF) through their Science Links program. The HBRF is a non-profit organization that develops new initiatives
linking ecosystem science and public policy. The Science Links program enhances the exchange of information among scientists, land managers, and policy-makers. The first two efforts focused on acidic deposition and anthropogenic N and resulted in coverage by over 300 media outlets. The U.S. EPA and the U.S. Senate Environment and Public Works Committee have used Science Links information to evaluate policy options related to acidic deposition. HBRF also provides information to the public and K-12 students through field trips, slideshow presentations, and published material.
Publications
- No publications reported this period
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