Now showing items 173-192 of 265

  • A pan-arctic evaluation of changes in river discharge during the latter half of the 20th century 

    McClelland, James W.; Dery, Stephen J.; Peterson, Bruce J.; Holmes, Robert M.; Wood, Eric F. (American Geophysical Union, 2006-03-30)
    Several recent publications have documented changes in river discharge from arctic and subarctic watersheds. Comparison of these findings, however, has been hampered by differences in time periods and methods of analysis. ...
  • Particle export from the upper ocean over the continental shelf of the west Antarctic Peninsula: A long-term record, 1992–2007 

    Ducklow, Hugh W.; Erickson, Matthew; Kelly, Joann; Montes-Hugo, Martin; Ribic, Christine A.; Smith, Raymond C.; Stammerjohn, Sharon E.; Karl, David M. (2008-03)
    We report on results of a long-term (1993-2007) time series sediment trap moored at 170 m to the west of the Antarctic Peninsula in the mid-continental shelf region (350 m depth; 64º30’ S, 66º00’ W). This is a region ...
  • Particle Flux in the deep Sargasso Sea : the 35-Year Oceanic Flux Program time series 

    Conte, Maureen H.; Weber, John C. (The Oceanography Society, 2014-03)
    The Oceanic Flux Program (OFP) sediment trap time series, the longest running time series of its kind, has continuously measured particle fluxes in the deep Sargasso Sea since 1978. OFP results provided the first direct ...
  • Past, present, and future roles of long-term experiments in the LTER Network 

    Knapp, Alan K.; Smith, Melinda D.; Hobbie, Sarah E.; Collins, Scott L.; Fahey, Timothy J.; Hansen, Gretchen J. A.; Landis, Douglas A.; La Pierre, Kimberly J.; Melillo, Jerry M.; Seastedt, Timothy R.; Shaver, Gaius R.; Webster, Jackson R. (American Institute of Biological Sciences, 2012-04)
    The US National Science Foundation—funded Long Term Ecological Research (LTER) Network supports a large (around 240) and diverse portfolio of long-term ecological experiments. Collectively, these long-term experiments have ...
  • Pattern and variation of C:N:P ratios in China’s soils : a synthesis of observational data 

    Tian, Hanqin; Chen, Guangsheng; Zhang, Chi; Melillo, Jerry M.; Hall, Charles A. S. (2009-09-01)
    Inspired by previous studies that have indicated consistent or even well-constrained relationships among carbon (C), nitrogen (N) and phosphorus (P) in soils, we have endeavored to explore general soil C:N:P ratios in ...
  • Permafrost degradation and methane : low risk of biogeochemical climate-warming feedback 

    Gao, Xiang; Schlosser, C. Adam; Sokolov, Andrei P.; Walter Anthony, Katey M.; Zhuang, Qianlai; Kicklighter, David W. (IOP Publishing, 2013-07-10)
    Climate change and permafrost thaw have been suggested to increase high latitude methane emissions that could potentially represent a strong feedback to the climate system. Using an integrated earth-system model framework, ...
  • Plant community responses to experimental warming across the tundra biome 

    Walker, Marilyn D.; Wahren, C. Henrik; Hollister, Robert D.; Henry, Greg H. R.; Ahlquist, Lorraine E.; Alatalo, Juha M.; Bret-Harte, M. Syndonia; Calef, Monika P.; Callaghan, Terry V.; Carroll, Amy B.; Epstein, Howard E.; Jonsdottir, Ingibjorg S.; Klein, Julia A.; Magnusson, Borgbor; Molau, Ulf; Oberbauer, Steven F.; Rewa, Steven P.; Robinson, Clare H.; Shaver, Gaius R.; Suding, Katharine N.; Thompson, Catharine C.; Tolvanen, Anne; Totland, Orjan; Turner, P. Lee; Tweedie, Craig E.; Webber, Patrick J.; Wookey, Philip A. (National Academy of Sciences of the USA, 2006-01-20)
    Recent observations of changes in some tundra ecosystems appear to be responses to a warming climate. Several experimental studies have shown that tundra plants and ecosystems can respond strongly to environmental change, ...
  • Plant functional types do not predict biomass responses to removal and fertilization in Alaskan tussock tundra 

    Bret-Harte, M. Syndonia; Mack, Michelle C.; Goldsmith, Gregory R.; Sloan, Daniel B.; DeMarco, Jennie; Shaver, Gaius R.; Ray, Peter M.; Biesinger, Zy; Chapin, F. Stuart (John Wiley & Sons, 2008-04-15)
    Plant communities in natural ecosystems are changing and species are being lost due to anthropogenic impacts including global warming and increasing nitrogen (N) deposition. We removed dominant species, combinations of ...
  • Plant nitrogen dynamics in fertilized and natural New England salt marshes : a paired 15N tracer study 

    Drake, Deanne C.; Peterson, Bruce J.; Deegan, Linda A.; Harris, L. A.; Miller, E. E.; Warren, R. Scott (Inter-Research, 2008-02-07)
    We examined the effects of increased nutrient availability on nitrogen (N) dynamics in dominant New England salt marsh plants (tall and stunted Spartina alterniflora and S. patens) using paired large-scale nutrient and ...
  • Potential influence of climate-induced vegetation shifts on future land use and associated land carbon fluxes in Northern Eurasia 

    Kicklighter, David W.; Cai, Y.; Zhuang, Qianlai; Parfenova, E. I.; Paltsev, S.; Sokolov, Andrei P.; Melillo, Jerry M.; Reilly, John M.; Tchebakova, Nadja M.; Lu, X. (IOP Publishing, 2014-03-21)
    Climate change will alter ecosystem metabolism and may lead to a redistribution of vegetation and changes in fire regimes in Northern Eurasia over the 21st century. Land management decisions will interact with these ...
  • Predicting microbial nitrate reduction pathways in coastal sediments 

    Algar, Christopher K.; Vallino, Joseph J. (Inter-Research, 2014-01-23)
    We present an ecosystem model that describes the biogeochemistry of a sediment nitrate reducing microbial community. In the model, the microbial community is represented as a distributed metabolic network. Biogeochemical ...
  • Probabilistic forecast for twenty-first-century climate based on uncertainties in emissions (without policy) and climate parameters 

    Sokolov, Andrei P.; Stone, P. H.; Forest, C. E.; Prinn, Ronald G.; Sarofim, Marcus C.; Webster, M.; Paltsev, S.; Schlosser, C. Adam; Kicklighter, David W.; Dutkiewicz, Stephanie; Reilly, John M.; Wang, C.; Felzer, Benjamin S.; Melillo, Jerry M.; Jacoby, H. D. (American Meteorological Society, 2009-10-01)
    The Massachusetts Institute of Technology (MIT) Integrated Global System Model is used to make probabilistic projections of climate change from 1861 to 2100. Since the model’s first projections were published in 2003, ...
  • The processing and impact of dissolved riverine nitrogen in the Arctic Ocean 

    Tank, Suzanne E.; Manizza, Manfredi; Holmes, Robert M.; McClelland, James W.; Peterson, Bruce J. (Springer, 2011-06-11)
    Although the Arctic Ocean is the most riverine-influenced of all of the world’s oceans, the importance of terrigenous nutrients in this environment is poorly understood. This study couples estimates of circumpolar riverine ...
  • Processing arctic eddy-flux data using a simple carbon-exchange model embedded in the ensemble Kalman filter 

    Rastetter, Edward B.; Williams, Mathew; Griffin, Kevin L.; Kwiatkowski, Bonnie L.; Tomasky, Gabrielle; Potosnak, Mark J.; Stoy, Paul C.; Shaver, Gaius R.; Stieglitz, Marc; Hobbie, John E.; Kling, George W. (Ecological Society of America, 2010-07)
    Continuous time-series estimates of net ecosystem carbon exchange (NEE) are routinely made using eddy covariance techniques. Identifying and compensating for errors in the NEE time series can be automated using a signal ...
  • Quantifying the production of dissolved organic nitrogen in headwater streams using 15N tracer additions 

    Johnson, Laura T.; Tank, Jennifer L.; Hall, Robert O.; Mulholland, Patrick J.; Hamilton, Stephen K.; Valett, H. Maurice; Webster, Jackson R.; Bernot, Melody J.; McDowell, William H.; Peterson, Bruce J.; Thomas, Suzanne M. (Association for the Sciences of Limnology and Oceanography, 2013-07)
    Most nitrogen (N) assimilation in lake and marine ecosystems is often subsequently released via autochthonous dissolved organic nitrogen (DON) production, but autochthonous DON production has yet to be quantified in flowing ...
  • Rapid screening for freshwater bacterial groups by using reverse line blot hybridization 

    Zwart, Gabriel; van Hannen, Erik J.; Kamst-van Agterveld, Miranda P.; Van der Gucht, Katleen; Lindstrom, Eva S.; Van Wichelen, Jeroen; Lauridsen, Torben; Crump, Byron C.; Han, Suk-Kyun; Declerck, Steven (American Society for Microbiology, 2003-10)
    The identification of phylogenetic clusters of bacteria that are common in freshwater has provided a basis for probe design to target important freshwater groups. We present a set of 16S ribosomal RNA gene-based oligonucleotide ...
  • Recent changes in nitrate and dissolved organic carbon export from the upper Kuparuk River, North Slope, Alaska 

    McClelland, James W.; Stieglitz, Marc; Pan, Feifei; Holmes, Robert M.; Peterson, Bruce J. (American Geophysical Union, 2007-11-08)
    Export of nitrate and dissolved organic carbon (DOC) from the upper Kuparuk River between the late 1970s and early 2000s was evaluated using long-term ecological research (LTER) data in combination with solute flux and ...
  • Reconciling carbon-cycle concepts, terminology, and methods 

    Chapin, F. Stuart; Woodwell, G. M.; Randerson, James T.; Rastetter, Edward B.; Lovett, G. M.; Baldocchi, Dennis D.; Clark, D. A.; Harmon, Mark E.; Schimel, David S.; Valentini, R.; Wirth, C.; Aber, J. D.; Cole, Jonathan J.; Goulden, Michael L.; Harden, J. W.; Heimann, M.; Howarth, Robert W.; Matson, P. A.; McGuire, A. David; Melillo, Jerry M.; Mooney, H. A.; Neff, Jason C.; Houghton, Richard A.; Pace, Michael L.; Ryan, M. G.; Running, Steven W.; Sala, Osvaldo E.; Schlesinger, William H.; Schulze, E.-D. (2006-01-06)
    Recent patterns and projections of climatic change have focused increased scientific and public attention on patterns of carbon (C) cycling and its controls, particularly the factors that determine whether an ecosystem is ...
  • Recovery from disturbance requires resynchronization of ecosystem nutrient cycles 

    Rastetter, Edward B.; Yanai, Ruth D.; Thomas, R. Q.; Vadeboncoeur, M. A.; Fahey, Timothy J.; Fisk, M. C.; Kwiatkowski, Bonnie L.; Hamburg, S. P. (Ecological Society of America, 2013-04)
    Nitrogen (N) and phosphorus (P) are tightly cycled in most terrestrial ecosystems, with plant uptake more than 10 times higher than the rate of supply from deposition and weathering. This near-total dependence on recycled ...
  • The regional and global significance of nitrogen removal in lakes and reservoirs 

    Harrison, John A.; Maranger, Roxane J.; Alexander, Richard B.; Giblin, Anne E.; Jacinthe, Pierre-Andre; Mayorga, Emilio; Seitzinger, Sybil P.; Sobota, Daniel J.; Wollheim, Wilfred M. (2008-06-25)
    Human activities have greatly increased the transport of biologically available N through watersheds to potentially sensitive coastal ecosystems. Lentic water bodies (lakes and reservoirs) have the potential to act as ...