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Author (up) Albani, M.; Medvigy, D.; Hurtt, G.C.; Moorcroft, P.R. file  url
  Title The contributions of land-use change, CO2 fertilization, and climate variability to the Eastern US carbon sink Type Journal Article
  Year 2006 Publication Global Change Biology Abbreviated Journal Global Change Biol  
  Volume 12 Issue 12 Pages 2370-2390  
  Keywords Climate Variability; CO2 Fertilization; CO2 Fluxes; Disturbance History; Eastern United States; Ecosystem Demography (ED) Model; Forest Harvesting; Land-use History; Regional-scale Uptake; Terrestrial Carbon Sink  
  Abstract Atmospheric measurements and land-based inventories imply that terrestrial ecosystems in the northern hemisphere are taking up significant amounts of anthropogenic cabon dioxide (CO2) emissions; however, there is considerable disagreement about the causes of this uptake, and its expected future trajectory. In this paper, we use the ecosystem demography (ED) model to quantify the contributions of disturbance history, CO2 fertilization and climate variability to the past, current, and future terrestrial carbon fluxes in the Eastern United States. The simulations indicate that forest regrowth following agricultural abandonment accounts for uptake of 0.11 Pg C yr−1 in the 1980s and 0.15 Pg C yr−1 in the 1990s, and regrowth following forest harvesting accounts for an additional 0.1 Pg C yr−1 of uptake during both these decades. The addition of CO2 fertilization into the model simulations increases carbon uptake rates to 0.38 Pg C yr−1 in the 1980s and 0.47 Pg C yr−1 in the 1990s. Comparisons of predicted aboveground carbon uptake to regional-scale forest inventory measurements indicate that the model's predictions in the absence of CO2 fertilization are 14% lower than observed, while in the presence of CO2 fertilization, predicted uptake rates are 28% larger than observed. Comparable results are obtained from comparisons of predicted total Net Ecosystem Productivity to the carbon fluxes observed at the Harvard Forest flux tower site and in model simulations free-air CO2 enrichment (FACE) experiments. These results imply that disturbance history is the principal mechanism responsible for current carbon uptake in the Eastern United States, and that conventional biogeochemical formulations of plant growth overestimate the response of plants to rising CO2 levels. Model projections out to 2100 imply that the carbon uptake arising from forest regrowth will increasingly be dominated by forest regrowth following harvesting. Consequently, actual carbon storage declines to near zero by the end of the 21st century as the forest regrowth that has occurred since agricultural abandonment comes into equilibrium with the landscape's new disturbance regime. Incorporating interannual climate variability into the model simulations gives rise to large interannual variation in regional carbon fluxes, indicating that long-term measurements are necessary to detect the signature of processes that give rise to long-term uptake and storage.  
  Call Number Serial 875  
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Author (up) Ardiel, E.L.; Rankin, C.H. file  url
  Title C. elegans: social interactions in a “nonsocial” animal Type Journal Article
  Year 2009 Publication Advances in Genetics Abbreviated Journal Adv Genet  
  Volume 68 Issue Pages 1-22  
  Keywords Animals; Behavior, Animal; Caenorhabditis elegans/genetics/*physiology; Caenorhabditis elegans Proteins/genetics; Ecosystem; Female; Genetics, Behavioral; Male; Pheromones/physiology; Social Behavior  
  Abstract As self-fertilizing nematodes, Caenorhabditis elegans do not normally come to mind when one thinks of social animals. However, their reproductive mode is optimized for rapid population growth, and although they do not form structured societies, conspecifics are an important source of sensory input. A pheromone signal underlies multiple complex behaviors, including diapause, male-mating, and aggregation. The use of C. elegans in sociogenetics research allows for the analysis of social interactions at the level of genes, circuits, and behaviors. This chapter describes natural polymorphisms in mab-23, plg-1, npr-1, and glb-5 as they relate to two C. elegans social behaviors: male-mating and aggregation.  
  Call Number Serial 1074  
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Author (up) Baustian, J.; Mendelssohn, I.; Lin, Q.; Rapp, J. file  url
  Title In situ burning restores the ecological function and structure of an oil-impacted coastal marsh Type Journal Article
  Year 2010 Publication Environmental Management Abbreviated Journal Environ Manage  
  Volume 46 Issue 5 Pages 781-789  
  Keywords Alkanes/analysis; Biodiversity; Chemical Hazard Release; *Ecosystem; Environmental Monitoring; Environmental Remediation/*methods; Fires; Louisiana; Petroleum/*analysis; Polycyclic Hydrocarbons, Aromatic/analysis; Soil/chemistry; Soil Pollutants/analysis; Water Pollutants, Chemical/*analysis; *Wetlands  
  Abstract As the use of in situ burning for oil spill remediation in coastal wetlands accelerates, the capacity of this procedure to restore the ecological structure and function of oil-impacted wetlands becomes increasingly important. Thus, our research focused on evaluating the functional and structural recovery of a coastal marsh in South Louisiana to an in situ burn following a Hurricane Katrina-induced oil spill. Permanent sampling plots were set up to monitor marsh recovery in the oiled and burned areas as well as non-oiled and non-burned (reference) marshes. Plots were monitored for species composition, stem density, above- and below ground productivity, marsh resiliency, soil chemistry, soil residual oil, and organic matter decomposition. The burn removed the majority of the oil from the marsh, and structurally the marsh recovered rapidly. Plant biomass and species composition returned to control levels within 9 months; however, species richness remained somewhat lower in the oiled and burned areas compared to the reference areas. Recovery of ecological function was also rapid following the in situ burn. Aboveground and belowground plant productivity recovered within one growing season, and although decomposition rates were initially higher in the oiled areas, over time they became equivalent to those in reference sites. Also, marsh resiliency, i.e., the rate of recovery from our applied disturbances, was not affected by the in situ burn. We conclude that in situ burning is an effective way to remove oil and allow ecosystem recovery in coastal marshes.  
  Call Number Serial 130  
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Author (up) Besemer, K. file  url
doi  openurl
  Title Biodiversity, community structure and function of biofilms in stream ecosystems Type Journal Article
  Year 2015 Publication Research in Microbiology Abbreviated Journal Res Microbiol  
  Volume 166 Issue 10 Pages 774-781  
  Keywords Biofilm; Microbial diversity; Microbial ecology; Stream ecosystems  
  Abstract Multi-species, surface-attached biofilms often dominate microbial life in streams and rivers, where they contribute substantially to biogeochemical processes. The microbial diversity of natural biofilms is huge, and may have important implications for the functioning of aquatic environments and the ecosystem services they provide. Yet the causes and consequences of biofilm biodiversity remain insufficiently understood. This review aims to give an overview of current knowledge on the distribution of stream biofilm biodiversity, the mechanisms generating biodiversity patterns and the relationship between biofilm biodiversity and ecosystem functioning.  
  Call Number Serial 1206  
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Author (up) Brierley, A.S.; Kingsford, M.J. file  url
  Title Impacts of climate change on marine organisms and ecosystems Type Journal Article
  Year 2009 Publication Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 19 Issue 14 Pages R602-14  
  Keywords Animals; Carbon Dioxide/*chemistry; Demography; *Ecosystem; *Geography; *Greenhouse Effect; Marine Biology; Oceans and Seas; Population Dynamics; *Temperature; Climate change  
  Abstract Human activities are releasing gigatonnes of carbon to the Earth's atmosphere annually. Direct consequences of cumulative post-industrial emissions include increasing global temperature, perturbed regional weather patterns, rising sea levels, acidifying oceans, changed nutrient loads and altered ocean circulation. These and other physical consequences are affecting marine biological processes from genes to ecosystems, over scales from rock pools to ocean basins, impacting ecosystem services and threatening human food security. The rates of physical change are unprecedented in some cases. Biological change is likely to be commensurately quick, although the resistance and resilience of organisms and ecosystems is highly variable. Biological changes founded in physiological response manifest as species range-changes, invasions and extinctions, and ecosystem regime shifts. Given the essential roles that oceans play in planetary function and provision of human sustenance, the grand challenge is to intervene before more tipping points are passed and marine ecosystems follow less-buffered terrestrial systems further down a spiral of decline. Although ocean bioengineering may alleviate change, this is not without risk. The principal brake to climate change remains reduced CO(2) emissions that marine scientists and custodians of the marine environment can lobby for and contribute to. This review describes present-day climate change, setting it in context with historical change, considers consequences of climate change for marine biological processes now and in to the future, and discusses contributions that marine systems could play in mitigating the impacts of global climate change.  
  Call Number Serial 2155  
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