Digital Commons Network^™

Greenhouse Gas And Nitrogen Inventory Report For Municipal And School Operations, Jackson H. Kaspari, Elena Piekut

The Sustainability Institute Publications

The City of Dover recognizes the many challenges that a changing climate presents and acknowledges that municipalities have a responsibility to lead adaptation and greenhouse gas reduction efforts at the local level. Through a University of New Hampshire Sustainability Fellowship undertaken by UNH doctoral student Jackson Kaspari, the City of Dover has become the first municipality in North America to complete a baseline footprint for both greenhouse gas (GHG) and nitrogen impacts of local government operations. This inventory informs Dover’s policymakers, residents, property owners, and business owners on how to best introduce mitigation measures, helping Dover contribute to a global …

Will Dam Removal Increase Nitrogen Flux To Estuaries?, Arthur J. Gold, Kelly Addy, Alisa Morrison, Marissa Simpson

New Hampshire EPSCoR

To advance the science of dam removal, analyses of functions and benefits need to be linked to individual dam attributes and effects on downstream receiving waters. We examined 7550 dams in the New England (USA) region for possible tradeoffs associated with dam removal. Dam removal often generates improvements for safety or migratory fish passage but might increase nitrogen (N) flux and eutrophication in coastal watersheds. We estimated N loading and removal with algorithms using geospatial data on land use, stream flow and hydrography. We focused on dams with reservoirs that increase retention time at specific points of river reaches, creating …

Climate Change Decreases Nitrogen Pools And Mineralization Rates In Northern Hardwood Forests, Jorge Duran, Jennifer L. Morse, Peter M. Groffman, John L. Campbell, Lynn M. Christenson, Charles T. Driscoll, Timothy J. Fahey, Melany C. Fisk, Gene E. Likens, Jerry M. Melillo, Myron J. Mitchell, Pamela H. Templer, Matthew A. Vadeboncoeur

Faculty Publications

Nitrogen (N) supply often limits the productivity of temperate forests and is regulated by a complex mix of biological and climatic drivers. In excess, N is linked to a variety of soil, water, and air pollution issues. Here, we use results from an elevation gradient study and historical data from the long‐term Hubbard Brook Ecosystem Study (New Hampshire, USA) to examine relationships between changes in climate, especially during winter, and N supply to northern hardwood forest ecosystems. Low elevation plots with less snow, more soil freezing, and more freeze/thaw cycles supported lower rates of N mineralization than high elevation plots, …

History Of Nutrient Inputs To The Northeastern United States, 1930–2000, Rebecca L. Hale, Joseph H. Hoover, Wilfred M. Wollheim, Charles J. Vorosmarty

Faculty Publications

Humans have dramatically altered nutrient cycles at local to global scales. We examined changes in anthropogenic nutrient inputs to the northeastern United States (NE) from 1930 to 2000. We created a comprehensive time series of anthropogenic N and P inputs to 437 counties in the NE at 5 year intervals. Inputs included atmospheric N deposition, biological N2 fixation, fertilizer, detergent P, livestock feed, and human food. Exports included exports of feed and food and volatilization of ammonia. N inputs to the NE increased throughout the study period, primarily due to increases in atmospheric deposition and fertilizer. P inputs increased until …

Tracking Environmental Trends In The Great Bay Estuarine System Through Comparisons Of Historical And Present-Day Green And Red Algal Community Structure And Nutrient Content, Jeremy C. Nettleton, Christopher D. Neefus, Arthur C. Mathieson, Larry G. Harris

PREP Reports & Publications

Monitoring macroalgae populations is an effective means of detecting long term water quality changes in estuarine systems. To investigate the environmental status of New Hampshire’s Great Bay National Estuarine Research Reserve, this study assessed the abundance/distribution of macrophytes, particularly Gracilaria and Ulva species, relative to eutrophication patterns; compared historical (1970s-1990s) and current algal biomass/cover at several sites; and compared Ulva and Gracilaria tissue N/P content to ambient and historical levels. Ulva and Gracilaria biomass/cover have increased significantly at several sites. Cover by Ulva species, at seasonal maxima, was over 90 times the value recorded in the 1970s at Lubberland Creek, …

Fertilizer And Stormwater Runoff Outreach Program In Newcastle, Nh, David Anderson

PREP Reports & Publications

The New Hampshire Coastal Protection Partnership (NH Coast) implemented a year long pilot public education and outreach program in the Town of New Castle aimed at reducing nitrogen pollution from lawn fertilizers and promoting rain gardens as a solution to storm water runoff and nonpoint source pollution. A total of 77 landowners representing 138 acres of land pledged to either not use lawn fertilizers or use only low phosphorus, slow release nitrogen brands. The program also resulted in the installation of New Castle’s first demonstration rain garden.

Meta-Analysis Of Fertilization Experiments Indicates Multiple Limiting Nutrients In Northeastern Deciduous Forests, Matthew A. Vadeboncoeur

Earth Systems Research Center

It is widely accepted that nitrogen limits primary production in temperate forests, although co-limitation by N and P has also been suggested, and on some soils Ca and base cations are in short supply. I conducted a meta-analysis to assess the strength of existing experimental evidence for limitation of primary production by N, P, and Ca in hardwood forests of the northeastern United States and southeastern Canada, using data from 35 fertilization experiments in deciduous forests on glaciated soils across the region.

There is strong evidence for N limitation (formal meta-analysis weighted mean response ratio = 1.51, p < 0.01; simple mean = 1.42, p < 0.001). Forest productivity also tends to increase with additions of P (simple mean = 1.15, p = 0.05) and Ca (simple mean = 1.36 p < 0.001). Across all treatments, 85% of response ratios were positive. Multiple-element additions had larger effects than single elements, but factorial experiments showed little evidence of synergistic effects between nutrient additions. Production responses correlated positively with the rate of N fertilization, but this effect was reduced at high rates of ambient N deposition.

Albedo Estimates For Land Surface Models And Support For A New Paradigm Based On Foliage Nitrogen Concentration, D. Y. Hollinger, Scott V. Ollinger, Andrew D. Richardson, T. P. Meyers, D. B. Dail, M. E. Martin, N. A. Scott, T. J. Arkebauer, D. D. Baldocchi, K. L. Clark, P. S. Curtis, K. J. Davis, A. R. Desai, D. Dragoni, M. L. Goulden, L. Gu, G. G. Katul, S. G. Pallardy, K. T. Paw, H. P. Schmid, P. C. Stoy, A. E. Suyker, S. B. Verma

Faculty Publications

Vegetation albedo is a critical component of the Earth's climate system, yet efforts to evaluate and improve albedo parameterizations in climate models have lagged relative to other aspects of model development. Here, we calculated growing season albedos for deciduous and evergreen forests, crops, and grasslands based on over 40 site‐years of data from the AmeriFlux network and compared them with estimates presently used in the land surface formulations of a variety of climate models. Generally, the albedo estimates used in land surface models agreed well with this data compilation. However, a variety of models using fixed seasonal estimates of albedo …

Nutrient Allocations And Metabolism In Two Collembolans With Contrasting Reproduction And Growth Strategies, Thomas Larsen, Marc Ventura, Christian Damgaard, Erik A. Hobbie, Paul Henning Krogh

Faculty Publications

Physiological mechanisms such as allocation and release of nutrients are keys to understanding an animal's adaptation to a particular habitat. This study investigated how two detrivores with contrasting life‐history traits allocated carbon (C) and nitrogen (N) to growth, reproduction and metabolism. As model organisms we used the collembolans, Proisotoma minuta (Tullberg 1871) and Protaphorura fimata (Gisin 1952).

To estimate allocations of C and N in tissue, we changed the isotopic composition of the animal's yeast diets when they became sexually mature and followed isotope turnover in tissue, growth and reproduction for 28 days. In addition, we measured the composition of …

Dynamics Of N Removal Over Annual Time Periods In A Suburban River Network, Wilfred M. Wollheim, Bruce J. Peterson, S. M. Thomas, Charles S. Hopkinson, Charles J. Vorosmarty

Faculty Publications

River systems are dynamic, highly connected water transfer networks that integrate a wide range of physical and biological processes. We used a river network nitrogen (N) removal model with daily temporal resolution to evaluate how elevated N inputs, saturation of the denitrification and total nitrate removal processes, and hydrologic conditions interact to determine the amount, timing and distribution of N removal in the fifth‐order river network of a suburban 400 km2 basin. Denitrification parameters were based on results from whole reach 15NO3 tracer additions. The model predicted that between 15 and 33% of dissolved inorganic nitrogen (DIN) inputs were denitrified …

Global N Removal By Freshwater Aquatic Systems Using A Spatially Distributed, Within‐Basin Approach, Wilfred M. Wollheim, Charles J. Vorosmarty, A. F. Bouwman, Pamela Green, John Harrison, Ernst Linder, Bruce J. Peterson, Sybil P. Seitzinger, James P. M. Syvitski

Faculty Publications

We explored the role of aquatic systems in the global N cycle using a spatially distributed, within‐basin, aquatic nitrogen (N) removal model, implemented within the Framework for Aquatic Modeling in the Earth System (FrAMES‐N). The model predicts mean annual total N (TN) removal by small rivers (with drainage areas from 2.6–1000 km2), large rivers, lakes, and reservoirs, using a 30′ latitude × longitude river network to route and process material from continental source areas to the coastal zone. Mean annual aquatic TN removal (for the mid‐1990s time period) is determined by the distributions of aquatic TN inputs, mean annual hydrological …

Factors Affecting Ammonium Uptake In Streams - An Inter-Biome Perspective, Jackson R. Webster, Patrick J. Mulholland, Jennifer L. Tanks, H. Maurice Valett, Walter K. Dodds, Bruce J. Peterson, William B. Bowden, Clifford N. Dahm, Stuart Findlay, Stanley V. Gregory, Nancy B. Grimm, Stephen K. Hamilton, Sherri L. Johnson, Eugenia Marti, William H. Mcdowell, Judy L. Meyer, Donna D. Morrall, Steven A. Thomas, Wilfred M. Wollheim

Faculty Publications

The Lotic Intersite Nitrogen experiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and from desert to rainforest. Measurements at each site included physical, hydraulic and chemical characteristics, biological parameters, whole-stream metabolism and ammonium uptake. Ammonium uptake was measured by injection of '5~-ammonium and downstream measurements of 15N-ammonium concentration. 3. We found no general, statistically significant relationships that explained the variability …

Direct Estimation Of Aboveground Forest Productivity Through Hyperspectral Remote Sensing Of Canopy Nitrogen, Marie-Louise Smith, Scott V. Ollinger, Mary E. Martin, John D. Aber, Richard A. Hallett, Christine L. Goodale

Faculty Publications

The concentration of nitrogen in foliage has been related to rates of net photosynthesis across a wide range of plant species and functional groups and thus represents a simple and biologically meaningful link between terrestrial cycles of carbon and nitrogen. Although foliar N is used by ecosystem models to predict rates of leaf‐level photosynthesis, it has rarely been examined as a direct scalar to stand‐level carbon gain. Establishment of such relationships would greatly simplify the nature of forest C and N linkages, enhancing our ability to derive estimates of forest productivity at landscape to regional scales. Here, we report on …

Modeling Physical And Chemical Climate Of The Northeastern United States For A Geographic Information System, Scott V. Ollinger, John D. Aber, Anthony C. Federer, Gary M. Lovett, Jennifer M. Ellis

Faculty Publications

A model of physical and chemical climate was developed for New York and New England that can be used in a GIs for integration with ecosystem models. The variables included are monthly average maximum and minimum daily temperatures, precipitation, humidity, and solar radiation, as well as annual atmospheric deposition of sulfur and nitrogen. Equations generated from regional data bases were combined with a digital elevation model of the region to generate digital coverages of each variable.