The response of organic matter mineralisation to nutrient and substrate additions in sub-arctic soils

Copyright © 2010 Elsevier. NOTICE: This is the author’s version of a work accepted for publication by Elsevier. Changes resulting from the publishing process, including peer review, editing, corrections, structural formatting and other quality control mechanisms, may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Soil Biology and Biochemistry, 2010, Vol. 42, Issue 1, pp. 92 – 100, http://dx.doi.org/10.1016/j.soilbio.2009.10.004Global warming in the Arctic may alter decomposition rates in Arctic soils and therefore nutrient availability. In addition, changes in the length of the growing season may increase plant productivity and the rate of labile C input below ground. We carried out an experiment in which inorganic nutrients (NH4NO3 and NaPO4) and organic substrates (glucose and glycine) were added to soils sampled from across the mountain birch forest-tundra heath ecotone in northern Sweden (organic and mineral soils from the forest, and organic soil only from the heath). Carbon dioxide production was then monitored continuously over the following 19 days. Neither inorganic N nor P additions substantially affected soil respiration rates when added separately. However, combined N and P additions stimulated microbial activity, with the response being greatest in the birch forest mineral soil (57% increase in CO2 production compared with 26% in the heath soil and 8% in the birch forest organic soil). Therefore, mineralisation rates in these soils may be stimulated if the overall nutrient availability to microbes increases in response to global change, but N deposition alone is unlikely to enhance decomposition. Adding either, or both, glucose and glycine increased microbial respiration. Isotopic separation indicated that the mineralisation of native soil organic matter (SOM) was stimulated by glucose addition in the heath soil and the forest mineral soil, but not in the forest organic soil. These positive ‘priming’ effects were lost following N addition in forest mineral soil, and following both N and P additions in the heath soil. In order to meet enhanced microbial nutrient demand, increased inputs of labile C from plants could stimulate the mineralisation of SOM, with the soil C stocks in the tundra-heath potentially most vulnerable

Complexity management through product portfolio cost modeling and optimization

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; in conjunction with the Leaders for Global Operations Program at MIT, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 61).A significant amount of complexity exists within the brand and product portfolios of PharmaCo. This complexity is driven by several factors: first, medical needs for differing products and dosages; second, marketing requests for new configurations of current product offerings; third, unique regulations and requirements for individual country markets; fourth, product portfolio growth from acquisition activity. This complexity increases both production costs and support costs (such as planning and procurement) for PharmaCo. The focus of this project is to reduce the complexity in the brand and SKU portfolios at PharmaCo. Two approaches can be utilized to reduce complexity in the product portfolio. First, measures can be taken to reduce already existing SKUs and brands. This has largely been the focus of previous efforts at PharmaCo, although additional work remains in this area. Previous analyses have focused on providing recommendations for pruning specific SKUs and divesting or pruning specific brands. Second, measures can be taken to manage the future proliferation of SKUs and brands in order to control future complexity growth. This approach has been largely unaddressed in previous internship projects and will be a major focus of the current project. It is first necessary to clearly understand all costs that are associated with complexity. Consequently, the first step of this project was to conduct site visits with multiple plants in order to learn all costs that are impacted by complexity. At these site visits, cross functional groups involved in all aspects of operations at the site were identified and consulted. Additionally, Marketing was contacted to understand complexity costs that affect Marketing. Both cost elements will be combined to develop a complexity cost model. This model is being piloted and applied to a stable brand that still has level or increasing volumes over the next several years.by Peter Sommerkorn.S.M.M.B.A

No evidence for compensatory thermal adaptation of soil microbial respiration in the study of Bradford et al. (2008)

Bradford et al. (2008) conclude that thermal adaptation will reduce the response of soil microbial respiration to rising global temperatures. However, we question both the methods used to calculate mass-specific respiration rates and the interpretation of the results. No clear evidence of thermal adaptation reducing soil microbial activity was produced

The age of CO2 released from soils in contrasting ecosystems during the arctic winter

Copyright © 2013 Elsevier. NOTICE: This is the author’s version of a work accepted for publication by Elsevier. Changes resulting from the publishing process, including peer review, editing, corrections, structural formatting and other quality control mechanisms, may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Soil Biology and Biochemistry, Vol. 63, pp. 1 – 4 DOI: http://dx.doi.org/10.1016/j.soilbio.2013.03.011In arctic ecosystems, winter soil respiration can contribute substantially to annual CO2 release, yet the source of this C is not clear. We analysed the 14C content of C released from plant-free plots in mountain birch forest and tundra-heath. Winter-respired CO2 was found to be a similar age (tundra) or older (forest) than C released during the previous autumn. Overall, our study demonstrates that the decomposition of older C can continue during the winter, in these two contrasting arctic ecosystems

Arctic Climate Feedbacks: Global Implications

Report describing sea-level rise and the associated flooding of coastal regions that may affect more than a quarter of the world’s population. It includes sections on atmospheric and ocean circulation feedbacks, ice sheets and sea-level rise feedbacks, marine and land carbon cycle feedbacks, and methane hydrate feedbacks

Arctic Climate Feedbacks: Global Implications, Executive Summary

Executive summary describing research to evaluate environmental feedback related to climate change. The summary includes a breakdown of the key findings from each chapter of the report, with charts and maps illustrating statistics

A participatory scenario method to explore the future of marine social‐ecological systems

Source at https://doi.org/10.1111/faf.12356.Anticipating future changes in marine social‐ecological systems (MSES) several decades into the future is essential in the context of accelerating global change. This is challenging in situations where actors do not share common understandings, practices, or visions about the future. We introduce a dedicated scenario method for the development of MSES scenarios in a participatory context. The objective is to allow different actors to jointly develop scenarios which contain their multiple visions of the future. The method starts from four perspectives: “fisheries management,” “ecosystem,” “ocean climate,” and “global context and governance” for which current status and recent trends are summarized. Contrasted scenarios about possible futures are elaborated for each of the four single perspectives before being integrated into multiple‐perspective scenarios. Selected scenarios are then developed into storylines. Focusing on individual perspectives until near the end allows actors with diverse cultures, interests and horizons to confront their own notions of the future. We illustrate the method with the exploration of the futures of the Barents Sea MSES by 2050. We emphasize the following lessons learned: first, many actors are not familiar with scenario building and attention must be paid to explaining the purpose, methodology, and benefits of scenarios exercises. Second, although the Barents Sea MSES is relatively well understood, uncertainties about its future are significant. Third, it is important to focus on unlikely events. Fourth, all perspectives should be treated equally. Fifth, as MSES are continuously changing, we can only be prepared for future changes if we collectively keep preparing