نتایج جستجو برای: river ecosystem

تعداد نتایج: 162076  

2013
Jie Wang Hiroshi Ishidaira Wenchao Sun Shaowei Ning

Suspended sediment concentration of a river can provide very important perspective on erosion or soil loss of one river basin ecosystem. The changes of land use and land cover, such as deforestation or afforestation, affect sediment yield process of a catchment through changing the hydrological cycle of the area. A sediment rating curve can describe the average relation between discharge and su...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1998
R E Turner N Qureshi N N Rabalais Q Dortch D Justić R F Shaw J Cope

Marine diatoms require dissolved silicate to form an external shell, and their growth becomes Si-limited when the atomic ratio of silicate to dissolved inorganic nitrogen (Si:DIN) approaches 1:1, also known as the "Redfield ratio." Fundamental changes in the diatom-to-zooplankton-to-higher trophic level food web should occur when this ratio falls below 1:1 and the proportion of diatoms in the p...

2013
Fort Collins

This volume is a state-of-knowledge synthesis of monitoring and research conducted on the Upper Verde River (UVR) of Arizona. It contains information on the history, hydrology, soils, geomorphology, vegetation, and fish fauna of the area that can help land managers and other scientists in successfully conducting ecosystem management and future monitoring and research in this important Southwest...

Journal: :Environmental management 2002
Eric W Larsen Steven E Greco

Understanding how hydraulic factors control alluvial river meander migration can help resource managers evaluate the long-term effects of floodplain management and bank stabilization measures. Using a numerical model based on the mechanics of flow and sediment transport in curved river channels, we predict 50 years of channel migration and suggest the planning and ecological implications of tha...

2009
Kirstie Fryirs Gary J. Brierley

An authentic approach to river rehabilitation emphasizes concerns for the natural values of a given place. As landscape considerations fashion the physical template upon which biotic associations take place, various geomorphic issues must be addressed in framing rehabilitation activities that strive to improve river health. An open-ended approach to river classification promotes applications th...

2014
John O. ESIN

The goal of this paper is to assess the principles and policy consideration for biodiversity conservation in the Cross River estuary using secondary data. This is informed by the need to document the status of the resources of the estuary as a basis for regulating the future exploitation and for the protection of the mangrove ecosystem in order to enhance sustainability.

Journal: :Brazilian journal of biology = Revista brasleira de biologia 2002
M de los A P Lizama A M Ambrósio

The condition factor for nine species of tropical freshwater fish of the Characidae family in the upper Paraná River floodplain is described. Fish were caught over a period of 12 months (February 1993 to March 1994). Knowledge of the nine species is important for adequate management and maintenance of the biological equilibrium of the ecosystem.

2017
David W. Johnston

For over a centmy, Dyke marsh along the Potomac River just south of Alexandria, VA, has been a favorite site for natural history studies. Despite earlier attempts at diking to create agricultural land and dredging for sand and gravel, the remaining marsh represents the last major tidal freshwater wetland on the upper Potomac River, and is now owned and maintained by the National Park Seivice as...

Journal: :Anais da Academia Brasileira de Ciencias 2011
Gislaine I Manetta Andréa Bialetzki Luiz A Martinelli Evanilde Benedito

The upper Paraná River floodplain is composed of several marginal lagoons, making it a natural breeding ground for many fish species at developmental stages. The aim of this study is to estimate the trophic positions of these fishes based on feed intake (measured via diet) and nitrogen assimilation (measured via δ(15)N). The monthly samplings were concentrated during the spawning season in the ...

2017
David J. Beale Avinash V. Karpe Warish Ahmed Stephen Cook Paul D. Morrison Christopher Staley Michael J. Sadowsky Enzo A. Palombo

A multi-omics approach was applied to an urban river system (the Brisbane River (BR), Queensland, Australia) in order to investigate surface water quality and characterize the bacterial population with respect to water contaminants. To do this, bacterial metagenomic amplicon-sequencing using Illumina next-generation sequencing (NGS) of the V5-V6 hypervariable regions of the 16S rRNA gene and un...

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