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Articles 1 - 6 of 6
Full-Text Articles in Life Sciences
The North American Carbon Program Multi-Scale Synthesis And Terrestrial Model Intercomparison Project – Part 1: Overview And Experimental Design, D. N. Huntzinger, C. Schwalm, A, M, Michalak, K. Schaefer, A. W. King, Y. Wei, A. Jacobson, S. Liu, R. B. Cook, W. M. Post, G. Berthier, D Hayes, M. Huang, A. Ito, H. Lei, Chaoqun (Crystal) Lu, J. Mao, C. H. Peng, S. Peng, B. Poulter, D. Ricciuto, X. Shi, Hanqin Tian, W. Wang, N. Zeng, F. Zhao, Q. Zhu
The North American Carbon Program Multi-Scale Synthesis And Terrestrial Model Intercomparison Project – Part 1: Overview And Experimental Design, D. N. Huntzinger, C. Schwalm, A, M, Michalak, K. Schaefer, A. W. King, Y. Wei, A. Jacobson, S. Liu, R. B. Cook, W. M. Post, G. Berthier, D Hayes, M. Huang, A. Ito, H. Lei, Chaoqun (Crystal) Lu, J. Mao, C. H. Peng, S. Peng, B. Poulter, D. Ricciuto, X. Shi, Hanqin Tian, W. Wang, N. Zeng, F. Zhao, Q. Zhu
Chaoqun (Crystal) Lu
Terrestrial biosphere models (TBMs) have become an integral tool for extrapolating local observations and understanding of land–atmosphere carbon exchange to larger regions. The North American Carbon Program (NACP) Multi-scale synthesis and Terrestrial Model Intercomparison Project (MsTMIP) is a formal model intercomparison and evaluation effort focused on improving the diagnosis and attribution of carbon exchange at regional and global scales. MsTMIP builds upon current and past synthesis activities, and has a unique framework designed to isolate, interpret, and inform understanding of how model structural differences impact estimates of carbon uptake and release. Here we provide an overview of the MsTMIP effort …
A Free-Ranging, Feral Mare Equus Caballus Affords Similar Maternal Care To Her Genetic And Adopted Offspring, Cassandra M.V. Nuñez, James S. Adelman, Daniel I. Rubenstein
A Free-Ranging, Feral Mare Equus Caballus Affords Similar Maternal Care To Her Genetic And Adopted Offspring, Cassandra M.V. Nuñez, James S. Adelman, Daniel I. Rubenstein
Cassandra M.V. Nuñez
Adoption of nongenetic offspring occurs in a variety of species but is rare in equids. We report a case of adoption by a free-ranging, feral mare Equus caballus and compare the maternal care received by her genetic offspring (born 1995) to that of her adopted offspring (born 1996) for the first 30 weeks of development. We compare five measures of care: (1) total time spent suckling, (2) mare aggression during suckling, (3) number of mare-terminated suckling bouts, (4) contact maintenance, and (5) mare-foal distance. For most behaviors, we detected no difference in the mare’s treatment of the two foals; however, …
Iron Oxidation Stimulates Organic Matter Decomposition In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver
Iron Oxidation Stimulates Organic Matter Decomposition In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver
Steven J. Hall
Humid tropical forests have the fastest rates of organic matter decomposition globally, which often coincide with fluctuating oxygen (O2) availability in surface soils. Microbial iron (Fe) reduction generates reduced iron [Fe(II)] under anaerobic conditions, which oxidizes to Fe(III) under subsequent aerobic conditions. We demonstrate that Fe (II) oxidation stimulates organic matter decomposition via two mechanisms: (i) organic matter oxidation, likely driven by reactive oxygen species; and (ii) increased dissolved organic carbon (DOC) availability, likely driven by acidification. Phenol oxidative activity increased linearly with Fe(II) concentrations (P < 0.0001, pseudo R2 = 0.79) in soils sampled within and among five tropical forest sites. A similar pattern occurred in the absence of soil, suggesting an abiotic driver of this reaction. No phenol oxidative activity occurred in soils under anaerobic conditions, implying the importance of oxidants such as O2 or hydrogen peroxide (H2O2) in addition to Fe(II). Reactions between Fe(II) and H2O2 generate hydroxyl radical, a strong nonselective oxidant of organic compounds. We found increasing consumption of H2O2 as soil Fe(II) concentrations increased, suggesting that reactive oxygen species produced by Fe(II) oxidation explained variation in phenol oxidative activity among samples. Amending soils with Fe(II) at field concentrations stimulated short-term C mineralization by up to 270%, likely via a second mechanism. Oxidation of Fe(II) drove a decrease in pH and a monotonic increase in DOC; a decline of two pH units doubled DOC, likely stimulating microbial respiration. We obtained similar results by manipulating soil acidity independently of Fe(II), implying that Fe(II) oxidation affected C substrate availability via pH fluctuations, in addition to producing reactive oxygen species. Iron oxidation coupled to organic matter decomposition contributes to rapid rates of C cycling across humid tropical forests in spite of periodic O2 limitation, and may help explain the rapid turnover of complex C molecules in these soils.
Effect Of Continued Nitrogen Enrichment On Greenhouse Gas Emissions From A Wetland Ecosystem In The Sanjiang Plain, Northeast China: A 5 Year Nitrogen Addition Experiment, Changchun Song, Lili Wang, Hanqin Tian, Deyan Liu, Chaoqun (Crystal) Lu, Xiaofeng Xu, Lihua Zhang, Guisheng Yang, Zhongmei Wan
Effect Of Continued Nitrogen Enrichment On Greenhouse Gas Emissions From A Wetland Ecosystem In The Sanjiang Plain, Northeast China: A 5 Year Nitrogen Addition Experiment, Changchun Song, Lili Wang, Hanqin Tian, Deyan Liu, Chaoqun (Crystal) Lu, Xiaofeng Xu, Lihua Zhang, Guisheng Yang, Zhongmei Wan
Chaoqun (Crystal) Lu
Mounting evidence supports that wetland ecosystems, one of the largest carbon pools on the earth, are exposed to ample nitrogen (N) additions due to atmospheric deposition or N loading from upstream agricultural fertilizer application. However, our understanding of how N enrichment affects the fluxes of greenhouse gases (GHGs) in wetlands is weak. A 5 year N addition experiment was conducted to examine the responses of CH4 and N2O fluxes as well as ecosystem respiration from wetlands in the Sanjiang Plain, Northeast China, through 2005 to 2009. Four levels of N addition (control, 0 kg N ha−1 yr−1; low-level, 60 kg …
Continuous, Pulsed And Disrupted Nutrient Subsidy Effects On Ecosystem Productivity, Stability, And Energy Flow, Michael J. Weber, Michael L. Brown
Continuous, Pulsed And Disrupted Nutrient Subsidy Effects On Ecosystem Productivity, Stability, And Energy Flow, Michael J. Weber, Michael L. Brown
Michael J Weber Dr
Resource pulses and subsidies can supply ecosystems with an important source of nutrients that supports additional productivity at multiple trophic levels. Common carp Cyprinus carpio provide ecosystems with a continuous nutrient subsidy through bioturbation and excretion but may also initiate a nutrient pulse through carcass decomposition. We examined how continuous (common carp foraging and excretion), pulsed (carcass decomposition) and disrupted (carp introduced and then removed) nutrient subsidies differed in their ability to alter nutrient availability, ecosystem productivity and stability and energy flow. Nitrogen and phosphorus availability and primary production were highest in pulsed, intermediate in continuous and lowest for disrupted …
When Wet Gets Wetter: Decoupling Of Moisture, Redox Biogeochemistry, And Greenhouse Gas Fluxes In A Humid Tropical Forest Soil, Steven J. Hall, William H. Mcdowell, Whendee L. Silver
When Wet Gets Wetter: Decoupling Of Moisture, Redox Biogeochemistry, And Greenhouse Gas Fluxes In A Humid Tropical Forest Soil, Steven J. Hall, William H. Mcdowell, Whendee L. Silver
Steven J. Hall
Upland humid tropical forest soils are often characterized by fluctuating redox dynamics that vary temporally and spatially across the landscape. An increase in the frequency and intensity of rainfall events with climate change is likely to affect soil redox reactions that control the production and emissions of greenhouse gases. We used a 24-day rainfall manipulation experiment to evaluate temporal and spatial trends of surface soil (0–20 cm) redox-active chemical species and greenhouse gas fluxes in the Luquillo Experimental Forest, Puerto Rico. Treatments consisted of a high rainfall simulation (60 mm day-1), a fluctuating rainfall regime, and a control. Water addition …