نتایج جستجو برای: environmental ecosystems

تعداد نتایج: 405619  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Hywel T P Williams Timothy M Lenton

The Earth possesses a number of regulatory feedback mechanisms involving life. In the absence of a population of competing biospheres, it has proved hard to find a robust evolutionary mechanism that would generate environmental regulation. It has been suggested that regulation must require altruistic environmental alterations by organisms and, therefore, would be evolutionarily unstable. This n...

2007
Simone D. LANGHANS Scott D. TIEGS Urs UEHLINGER Klement TOCKNER Simone D. Langhans

Environmental heterogeneity is a key regulator of ecological processes. Riverine floodplains are particularly heterogeneous and dynamic systems and loss of their natural environmental heterogeneity and dynamism as a consequence of human impacts constitutes their most serious threat. On river floodplains, flow and flood pulses create a shifting mosaic of channels, ponds, bars, islands, and ripar...

2005
PATRICK J. MULHOLLAND

'Environmental Sciences Division, Oak Ridge National Luboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 USA LDeparrment of Natural Resources and Environmental Sciences, University of Illinois, Urbana, Illinois 61801 USA ?Institute of Ecology. University of Georgia. Athens, Georgia 30602 USA -'Ecosystems Center. Marine Biological Luboratory, Woods Hole, Massachusetts 02543 USA 'Department of ...

Journal: :Journal of environmental management 2008
Ram Ranjan

This paper derives the optimal level of restorative efforts required to restore environments degraded by invasive species invasion. Specific attention is focused on a case when restoration faces the risk of failure through relapse of the restored environment caused by repeat invasions. The level of restored environment may also play a role in its future improvement or susceptibility to failure....

2016
Francisco Flores-López S. E. Galaitsi Marisa Escobar David Purkey

In the Peruvian Andes, water infiltration from tropical wetlands, called páramo, generates headwaters for downstream rivers. The hydrological processes of these wetlands are not well understood within the larger hydrological system, impeding efforts to mitigate the rapid environmental changes anticipated due to regional population growth and climate change. This study constructed and calibrated...

Journal: :Cadernos de saude publica 2005
Aldo Pacheco Ferreira

This study aimed to evaluate the co-occurrence of caffeine and the extent of its influence as compared to other traditional water quality parameters (microbiological and physico-chemical) in order to characterize it as an efficient indicator of anthropic pollution of urban aquatic environments. Caffeine is an ingredient in a variety of beverages (coffee, tea, and caffeinated soft drinks) and nu...

2017
V. Kuo W. R. Shoemaker M. E. Muscarella J. T. Lennon

We present here a draft genome assembly of Micrococcus sp. KBS0714, which was isolated from agricultural soil. The genome provides insight into the strategies that Micrococcus spp. use to contend with environmental stressors such as desiccation and starvation in environmental and host-associated ecosystems.

Journal: :global journal of environmental science and management 2016
a. padash s.a. jozi s.m.b. nabavi b. dehzad

in recent decades, necessity to protect environment has been a serious concern for all people and international communities. in appropriate development of human economic activities, subsistence dependence of the growing world population on nature decreases the natural diversity of ecosystems and habitats day by day and provides additional constraints for life and survival of wildlife. as a resu...

Journal: :Journal of theoretical biology 2008
Paolo D'Odorico Francesco Laio Luca Ridolfi Manuel T Lerdau

Recent research in ecology has concentrated on the effect of environmental changes on ecosystem structure and function. In most cases the focus has been on how ecosystems respond to changes in the mean values of environmental parameters, while the impact of changes in the variance has seldom been studied. However, changes in environmental variability may be important. For example, recent climat...

2004
W. R. Boynton

Productivity, trophic structure, and energy flow in the steady-state ecosystems of Silver Springs, Florida W.M. Kemp a,∗, W.R. Boynton b a Horn Point Laboratory, Center for Environmental Science, University of Maryland System, Box 775, Cambridge, MD 21613, USA b Chesapeake Biological Laboratory, Center for Environmental Science, University of Maryland System, 1 Williams Street, Solomons, MD 206...

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