نتایج جستجو برای: ecosystem cycles

تعداد نتایج: 171643  

Journal: :محیط شناسی 0
اطهره نژادی مجید مخدوم سید مسعود منوری علی بالی حمید فراهانی راد

human activities often adversely affect natural landscapes and ecosystems. natural landscapes consist of habitats, and habitat loss and fragmentation are major threats to biodiversity. environmental impact assessment (eia)as a systematic and well documented procedure to identify, describe and assess the direct and indirect effects of a developmental project in different environments does not co...

F. Li H. Lu L. Tong, R. Ding S. Ji S. Kang S. Li T. Du

Accurate estimation of leaf stomatal conductance (gs) is important in predicting carbon andwater cycles of terrestrial ecosystem. To estimate gs on field-grown soybean and maize underwater-stressed condition accurately, a modified optimal stomatal conductance (OSCM) modelwas established based on the relationship between marginal water cost of carbon gain and soilwater content by introducing a w...

2006
Michael S. Wetz Kenneth C. Hayes Alan J. Lewitus Jennifer L. Wolny David L. White

Tidal flow causes high temporal variability in environmental properties that impact ecosystem dynamics. Microbes such as phytoplankton are especially susceptible to tidal advection and mixing, and understanding their role in estuarine food webs and biogeochemical cycles requires information on their biomass and taxonomic composition over short time scales (e.g. tidal cycles). We conducted a sur...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Jennie Sirota Benjamin Baiser Nicholas J Gotelli Aaron M Ellison

Slow changes in underlying state variables can lead to "tipping points," rapid transitions between alternative states ("regime shifts") in a wide range of complex systems. Tipping points and regime shifts routinely are documented retrospectively in long time series of observational data. Experimental induction of tipping points and regime shifts is rare, but could lead to new methods for detect...

Journal: :international journal of environmental research 2011
l. lei l. jian w. yutao w. nvjie w. renqing

the value of wetlands is receiving increasing attention and the cost–benefit analyses (cba) is essential to evaluate the long-term effects of wetland rehabilitation projects. in order to guarantee the water quality of the south-to-north water diversion project of china (east route), the government of shandong province started a huge lakeshore wetland rehabilitation project in 2008. the cba appr...

Purpose: Considering the quantitative growth of university growth and technology centers in the country and the need for solutions to facilitate the success of these companies in global competition, this study identifies the indicators of innovation ecosystem of university growth and technology centers with the knowledge-based economy approach with data foundation approach. Methodology: This r...

2014
Sarah Q. Foster Robinson W. Fulweiler

*Correspondence: Robinson W. Fulweiler, Department of Earth and Environment, Boston University, 685 Commonwealth Avenue Rm. 130, Boston, MA 02215, USA e-mail: [email protected] Human activities have dramatically altered reactive nitrogen (N) availability in coastal ecosystems globally. Here we used a gradient of N loading found in a shallow temperate estuary (Waquoit Bay, Massachusetts, USA) to examin...

Journal: :international archives of health sciences 0
dehghani r. “environment health department, health faculty” and “social determinants of health research center”, kashan university of medical sciences, kashan, iran hasanbeiki o. health faculty, kashan university of medical sciences, ghotb ravandi boulevard, kashan, iran pourgholi m. environmental health engineering department, health faculty, kashan university of medical sciences, kashan, iran asgari j. english department, medicine faculty, kashan university of medical sciences, kashan, iran

aims: a very common species of leeches has been named as hirudo medicinalis. regarding to the application of leeches in medicine and their fast extinction, this study was performed in aquatic habitats of kashan aimed to determine the distribution of leeches and to provide information about their regional and habitat characteristics. materials & methods: this descriptive study was conducted duri...

2015
C. Rumpel A. Crème P. T. Ngo G. Velásquez M. L. Mora A. Chabbi

Grassland introduction into intensively managed agricultural landscapes may enhance soil organic matter (SOM) content and ecosystem services. However, the magnitude of this effect depends on grassland management practices, and their influence on the soil system. The aim of this paper is to highlight these impacts and their consequences for SOM dynamics and element cycling. We focused in particu...

2014
Summer B. Thyme Yifan Song T. J. Brunette Mindy D. Szeto Lara Kusak Philip Bradley David Baker

We describe the identification and characterization of novel homing endonucleases using genome database mining to identify putative target sites, followed by high throughput activity screening in a bacterial selection system. We characterized the substrate specificity and kinetics of these endonucleases by monitoring DNA cleavage events with deep sequencing. The endonuclease specificities revea...

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