Now showing items 41-60 of 262

  • Decreased mass specific respiration under experimental warming is robust to the microbial biomass method employed 

    Bradford, Mark A.; Wallenstein, Matthew D.; Allison, Steven D.; Treseder, Kathleen K.; Frey, Serita D.; Watts, Brian W.; Davies, Christian A.; Maddox, Thomas R.; Melillo, Jerry M.; Mohan, Jacqueline E.; Reynolds, James F. (2009-05)
    Hartley et al. question whether reduction in Rmass, under experimental warming, arises because of the biomass method. We show the method they treat as independent yields the same result. We describe why the substrate-depletion ...
  • Deforestation of watersheds of Panama : nutrient retention and export to streams 

    Valiela, Ivan; Barth-Jensen, Coralie; Stone, Thomas A.; Crusius, John; Fox, Sophia E.; Bartholomew, Megan (Springer, 2013-03-19)
    A series of eight watersheds on the Pacific coast of Panama where conversion of mature lowland wet forest to pastures by artisanal burning provided watershed-scale experimental units with a wide range of forest cover (23, ...
  • Denitrification across landscapes and waterscapes : a synthesis 

    Seitzinger, Sybil P.; Harrison, John A.; Bohlke, John K.; Bouwman, A. F.; Lowrance, R.; Peterson, Bruce J.; Tobias, Craig R.; Van Drecht, G. (Ecological Society of America, 2006-12)
    Denitrification is a critical process regulating the removal of bioavailable nitrogen (N) from natural and human-altered systems. While it has been extensively studied in terrestrial, freshwater, and marine systems, there ...
  • Denitrification and total nitrate uptake in streams of a tropical landscape 

    Potter, Jody D.; McDowell, William H.; Merriam, J. L.; Peterson, Bruce J.; Thomas, Suzanne M. (Ecological Society of America, 2010-12)
    Rapid increases in nitrogen (N) loading are occurring in many tropical watersheds, but the fate of N in tropical streams is not well documented. Rates of nitrate uptake and denitrification were measured in nine tropical ...
  • Depleted 15N in hydrolysable-N of arctic soils and its implication for mycorrhizal fungi–plant interaction 

    Yano, Yuriko; Shaver, Gaius R.; Giblin, Anne E.; Rastetter, Edward B. (2009-08)
    Uptake of nitrogen (N) via root-mycorrhizal associations accounts for a significant portion of total N supply to many vascular plants. Using stable isotope ratios (δ15N) and the mass balance among N pools of plants, ...
  • Differences in throughfall and net precipitation between soybean and transitional tropical forest in the southern Amazon, Brazil 

    Base, Frank; Elsenbeer, Helmut; Neill, Christopher; Krusche, Alex V. (2012-06)
    The expansion of soybean cultivation into the Amazon in Brazil has potential hydrological effects at local to regional scales. To determine the impacts of soybean agriculture on hydrology, a comparison of net precipitation ...
  • Differential physiological responses to environmental change promote woody shrub expansion 

    Heskel, Mary; Greaves, Heather; Kornfeld, Ari; Gough, Laura; Atkin, Owen K.; Turnbull, Matthew H.; Shaver, Gaius R.; Griffin, Kevin L. (John Wiley & Sons, 2013-03-13)
    Direct and indirect effects of warming are increasingly modifying the carbon-rich vegetation and soils of the Arctic tundra, with important implications for the terrestrial carbon cycle. Understanding the biological and ...
  • Differential responses of ammonia-oxidizing archaea and bacteria to long-term fertilization in a New England salt marsh 

    Peng, Xuefeng; Yando, Erik; Hildebrand, Erica; Dwyer, Courtney; Kearney, Anne; Waciega, Alex; Valiela, Ivan; Bernhard, Anne E. (Frontiers Media, 2013-01-22)
    Since the discovery of ammonia-oxidizing archaea (AOA), new questions have arisen about population and community dynamics and potential interactions between AOA and ammonia-oxidizing bacteria (AOB). We investigated the ...
  • The disappearing cryosphere : impacts and ecosystem responses to rapid cryosphere loss 

    Fountain, Andrew G.; Campbell, John L.; Schuur, Edward A. G.; Stammerjohn, Sharon E.; Williams, Mark W.; Ducklow, Hugh W. (American Institute of Biological Sciences, 2012-04)
    The cryosphere—the portion of the Earth's surface where water is in solid form for at least one month of the year—has been shrinking in response to climate warming. The extents of sea ice, snow, and glaciers, for example, ...
  • Discharge–calcium concentration relationships in streams of the Amazon and Cerrado of Brazil : soil or land use controlled 

    Markewitz, Daniel; Lamon, E. Conrad; Bustamante, Mercedes C.; Chaves, Joaquin E.; Figueiredo, Ricardo O.; Johnson, Mark S.; Krusche, Alex V.; Neill, Christopher; Silva, Jose S. O. (2011-02)
    Stream discharge-concentration relationships are indicators of terrestrial ecosystem function. Throughout the Amazon and Cerrado regions of Brazil rapid changes in land use and land cover may be altering these hydrochemical ...
  • Distribution, species composition and management implications of seed banks in southern New England coastal plain ponds 

    Neill, Christopher; Bezerra, Maira Ometto; McHorney, Richard; O’Dea, Claire B. (2008-12)
    Buried seeds that germinate during periods of low water or water level drawdown can play important roles in shaping plant community composition, community dynamics and species richness in ecosystems with fluctuating water ...
  • Does elevated CO2 alter silica uptake in trees? 

    Fulweiler, Robinson W.; Maguire, Timothy J.; Carey, Joanna C.; Finzi, Adrien C. (Frontiers Media, 2015-01-13)
    Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO2) have increased 40% over the last century and the amount of N cycling in the ...
  • Drought legacies influence the long-term carbon balance of a freshwater marsh 

    Rocha, Adrian V.; Goulden, Michael L. (American Geophysical Union, 2010-09-30)
    Experimental manipulations provide a powerful tool for understanding an ecosystem's response to environmental perturbation. We combined paired eddy covariance towers with an experimental manipulation of water availability ...
  • Dynamics of N removal over annual time periods in a suburban river network 

    Wollheim, Wilfred M.; Peterson, Bruce J.; Thomas, Suzanne M.; Hopkinson, Charles S.; Vorosmarty, Charles J. (American Geophysical Union, 2008-09-23)
    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 ...
  • Ecological constraints on planktonic nitrogen fixation in saline estuaries. I. Nutrient and trophic controls 

    Marino, Roxanne; Chan, Francis; Howarth, Robert W.; Pace, Michael L.; Likens, Gene E. (Inter-Research, 2006-03-15)
    Heterocystous, planktonic cyanobacteria capable of fixing atmospheric N2 into available nitrogen (N) are common and critically important to nutrient cycling in many lakes, yet they are rarely observed in estuaries at ...
  • Ecological homogenization of urban USA 

    Groffman, Peter M.; Cavender-Bares, Jeannine; Bettez, Neil D.; Grove, J. Morgan; Hall, Sharon J.; Heffernan, James B.; Hobbie, Sarah E.; Larson, Kelli L.; Morse, Jennifer L.; Neill, Christopher; Nelson, Kristen; O'Neil-Dunne, Jarlath; Ogden, Laura; Pataki, Diane E.; Polsky, Colin; Chowdhury, Rinku Roy; Steele, Meredith K. (Ecological Society of America, 2014-02)
    A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, residential lots, ...
  • Ecosystem biogeochemistry considered as a distributed metabolic network ordered by maximum entropy production 

    Vallino, Joseph J. (2009-09-18)
    We examine the application of the maximum entropy production principle for describing ecosystem biogeochemistry. Since ecosystems can be functionally stable despite changes in species composition, we utilize a distributed ...
  • Ecosystem feedbacks and cascade processes : understanding their role in the responses of Arctic and alpine ecosystems to environmental change 

    Wookey, Philip A.; Aerts, Rien; Bardgett, Richard D.; Baptist, Florence; Bråthen, Kari Anne; Cornelissen, Johannes H. C.; Gough, Laura; Hartley, Iain P.; Hopkins, David W.; Lavorel, Sandra; Shaver, Gaius R. (2008-09-11)
    Global environmental change, related to climate change and the deposition of airborne N-containing contaminants, has already resulted in shifts in plant community composition among plant functional types in arctic and ...
  • Ecosystem fluxes of hydrogen : a comparison of flux-gradient methods 

    Meredith, Laura K.; Commane, R.; Munger, J. W.; Dunn, A.; Tang, Jianwu; Wofsy, Steven C.; Prinn, Ronald G. (Copernicus Publications on behalf of the European Geosciences Union, 2014-09-03)
    Our understanding of biosphere–atmosphere exchange has been considerably enhanced by eddy covariance measurements. However, there remain many trace gases, such as molecular hydrogen (H2), that lack suitable analytical ...
  • Eddy correlation measurements of oxygen fluxes in permeable sediments exposed to varying current flow and light 

    Berg, Peter; Long, Matthew H.; Huettel, Markus; Rheuban, Jennie E.; McGlathery, Karen J.; Howarth, Robert W.; Foreman, Kenneth H.; Giblin, Anne E.; Marino, Roxanne (Association for the Sciences of Limnology and Oceanography, 2013-07)
    Based on noninvasive eddy correlation measurements at a marine and a freshwater site, this study documents the control that current flow and light have on sediment–water oxygen fluxes in permeable sediments. The marine ...