Extracellular Enzyme Activities and Soil Organic Matter Dynamics for Northern Hardwood Forests receiving Simulated Nitrogen Deposition

Anthropogenic nitrogen enrichment alters decomposition processes that control the flux of carbon (C) and nitrogen (N) from soil organic matter (SOM) pools. To link N-driven changes in SOM to microbial responses, we measured the potential activity of several extracellular enzymes involved in SOM degradation at nine experimental sites located in northern Michigan. Each site has three treatment plots (ambient, +30 and +80 kg N ha −1  y −1 ). Litter and soil samples were collected on five dates over the third growing season of N treatment. Phenol oxidase, peroxidase and cellobiohydrolase activities showed significant responses to N additions. In the Acer saccharum – Tilia americana ecosystem, oxidative activity was 38% higher in the litter horizon of high N treatment plots, relative to ambient plots, while oxidative activity in mineral soil showed little change. In the A. saccharum – Quercus rubra and Q. velutina – Q. alba ecosystems, oxidative activities declined in both litter (15 and 23%, respectively) and soil (29 and 38%, respectively) in response to high N treatment while cellobiohydrolase activity increased (6 and 39% for litter, 29 and 18% for soil, respectively). Over 3 years, SOM content in the high N plots has decreased in the Acer – Tilia ecosystem and increased in the two Quercus ecosystems, relative to ambient plots. For all three ecosystems, differences in SOM content in relation to N treatment were directly related ( r 2  = 0.92) to an enzyme activity factor that included both oxidative and hydrolytic enzyme responses.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42480/1/10533_2004_Article_7112.pd

Science and Technology Issues in the 115th Congress

Science and technology (S&T) have a pervasive influence over a wide range of issues confronting the nation. Public and private research and development spur scientific and technological advancement. Such advances can drive economic growth, help address national priorities, and improve health and quality of life. The constantly changing nature and ubiquity of science and technology frequently create public policy issues of congressional interest. The federal government supports scientific and technological advancement directly by funding and performing research and development and indirectly by creating and maintaining policies that encourage private sector efforts. Additionally, the federal government establishes and enforces regulatory frameworks governing many aspects of S&T activities. This report briefly outlines an array of science and technology policy issues that may come before the 115th Congress. Given the rapid pace of S&T advancement and its importance in many diverse public policy issues, S&T-related issues not discussed in this report may come before the 115th Congress. The selected issues are grouped into 9 categories: - Overarching S&T Policy Issues, - Agriculture, - Biomedical Research and Development, - Defense, - Energy, - Environment and Natural Resources, - Homeland Security, - Information Technology, - Physical and Material Sciences, and - Space. Each of these categories includes concise analysis of multiple policy issues. The material presented in this report should be viewed as illustrative rather than comprehensive. Each section identifies CRS reports, when available, and the appropriate CRS experts to contact for further information and analysis

Federal Prize Competitions

This report discusses federal prize competitions, which are a tool for incentivizing the achievement of scientific and technological innovation by offering monetary and non-monetary benefits (e.g., recognition) to competition participants. Prize competitions have a long history of use in both the public and private sectors, but have gained popularity in recent years. This report describes the background and current trends of federal prize competitions, potential policy considerations, and legislation in the 115th Congress

Defense Advanced Research Projects Agency: Overview and Issues for Congress

This report provides an overview of The Defense Advanced Research Projects Agency (DARPA), including the agency's organizational structure, characteristics (i.e., the "DARPA model"), and strategic priorities. The report also describes funding trends at DARPA and the Administration's FY2018 budget request. Finally, the report discusses select issues for possible congressional consideration, including the appropriate level of funding for the agency, technology transfer, and the potential role of DARPA in maintaining the technological superiority of the U.S. military

CRS In Focus

This report discusses the role of the Under Secretary of Defense for Research and Engineering and how the position fits into the organizational structure of the Defense Department

CRS In Focus

This report discusses the role of the Under Secretary of Defense for Research and Engineering and how the position fits into the organizational structure of the Defense Department

Federally Funded Academic Research Requirements: Background and Issues in Brief

This report contains background information and selected issues on federal regulations and administrative requirements related to federally-funded academic research, including a general overview and discussion of select issues

Advanced Gene Editing: CRISPR-Cas9

This report describes a new gene editing technology, known as CRISPR-Cas9, with the potential to revolutionize genetic engineering and the biotechnology industry. The report then provides information on the potential economic benefits of the technology and identifies some issues for congressional consideration, including the regulation of current and future products, national security concerns, and ethical and societal issues surrounding the use of the technology