نتایج جستجو برای: river ecosystem

تعداد نتایج: 162076  

2001
James McNames Tobias Kukulka

The Columbia River discharge plays a central role in North-East Pacific Ocean coastal ecosystem dynamics. A model is developed to predict non-stationary surface-salinity time-series in the North Pacific Ocean off-shore the Columbia River. The model takes wind velocities and Columbia River discharge as inputs only. Wind velocities are converted to smoothed wind stresses which are then integrated...

2013
Wei Sun Chunyu Xia Meiying Xu Jun Guo Aijie Wang Guoping Sun

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrification. However, limited information about the characteristics of AOA and AOB in the river ecosystem is available. The distribution and abundance of AOA and AOB in the sediments of the Dongjiang River, a drinking water source for Hong Kong, were investigated by clone library analysis and quantitative real-time PCR...

2017
Eric Snyder Stephen Balcombe Courtney Henderson

2000
John Loomis Paula Kent Liz Strange Kurt Fausch Alan Covich

Five ecosystem services that could be restored along a 45-mile section of the Platte river were described to respondents using a building block approach developed by an interdisciplinary team. These ecosystem services were dilution of wastewater, natural purification of water, erosion control, habitat for fish and wildlife, and recreation. Households were asked a dichotomous choice willingness ...

2017
Fabio F. Pereira Fabio Farinosi Mauricio E. Arias Eunjee Lee John Briscoe Paul R. Moorcroft

Land surface models are excellent tools for studying how climate change and land use affect surface hydrology. However, in order to assess the impacts of Earth processes on river flows, simulated changes in runoff need to be routed through the landscape. In this technical note, we describe the integration of the Ecosystem Demography (ED2) model with a hydrological routing scheme. The purpose of...

Journal: :Applied and environmental microbiology 2003
E González-Toril E Llobet-Brossa E O Casamayor R Amann R Amils

The Tinto River (Huelva, southwestern Spain) is an extreme environment with a rather constant acidic pH along the entire river and a high concentration of heavy metals. The extreme conditions of the Tinto ecosystem are generated by the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the Iberian Pyrite Belt. Molecular ecology techniques were used t...

Journal: :Remote Sensing 2017
Jia Zhu Zhihong Huang Hua Sun Guangxing Wang

The distribution of forest biomass in a river basin usually has obvious spatial heterogeneity in relation to the locations of the upper and lower reaches of the basin. In the subtropical region of China, a large amount of forest biomass, comprising diverse forest types, plays an important role in maintaining the balance of the regional carbon cycle. However, accurately estimating forest ecosyst...

2007
Yaw A. Twumasi Edmund C. Merem

In the Sub-Saharan African region of the River Niger Basin, where none of the major rivers is fully contained within the borders of a single nation, riverine ecosystem health monitoring is essential for survival. Even the globally proclaimed goals of sustainability and environmental security in the region are unattainable without using geospatial technologies of remote sensing and Geographic In...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Manuel del Jesus Romano Foti Andrea Rinaldo Ignacio Rodriguez-Iturbe

The spatial organization of functional vegetation types in river basins is a major determinant of their runoff production, biodiversity, and ecosystem services. The optimization of different objective functions has been suggested to control the adaptive behavior of plants and ecosystems, often without a compelling justification. Maximum entropy production (MEP), rooted in thermodynamics princip...

2014
Alexander K. Fremier Evan H. Girvetz Steven E. Greco Eric W. Larsen

Environmental legislation in the US (i.e. NEPA) requires defining baseline conditions on current rather than historical ecosystem conditions. For ecosystems with long histories of multiple environmental impacts, this baseline method can subsequently lead to a significantly altered environment; this has been termed a 'sliding baseline'. In river systems, cumulative effects caused by flow regulat...

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