نتایج جستجو برای: aquatic ecosystems

تعداد نتایج: 72145  

1998
G. MATHIAS KONDOLF

1. California is a tectonically active region with a Mediterranean climate, resulting in extreme spatial and temporal variability in river channel conditions. Restoration approaches that work in one part of the state may not succeed elsewhere. 2. Restoration projects should be planned and designed based on an understanding of geomorphological and ecological processes, rather than simply mimicry...

2001
Renato BAUDO

In Italy, Ecotoxicology has found a place with the Legislative Decree n. 152 (May 11, 1999), emanated in fulfilment of the Directives 91/271/CEE "urban waste-water treatment" and 91/676/CEE "protection of waters against pollution caused by nitrates from agricultural sources". This decree in reality goes beyond (actually anticipating the content of the Framework Directive on Water, still under w...

Journal: :محیط زیست طبیعی 0
مهدی بنایی گروه شیلات دانشکده منابع طبیعی، دانشگاه صنعتی خاتم الانبیا، بهبهان علیرضا میرواقفی- بیماریها گروه شیلات، دانشکده منابع طبیعی، دانشگاه تهران آنتونی سوردا گومیل گروه زیست شناسی دانشکده علوم زیستی دانشگاه ایلس بالرز اسپانیا غلامرضا رفیعی گروه شیلات، دانشکده منابع طبیعی، دانشگاه تهران کمال احمدی گروه شیلات، دانشگاه آزاد اسلامی، واحد تهران شمال و عضو باشگاه پژوهشگران جوان

pesticides are one of the most pollutants in aquatic ecosystems. monitoring of aquatic pollution with these compounds is very important. therefore, health status of aquatic animals can be used as a bio-indicator for pollution monitoring in surface waters. diazinon is an organophosphorous pesticide, which is found in the aquatic environment of iran. the concern has arisen over the ability of thi...

2000
Sven Brückner Kurt Sundermeyer

generalized interactions flexible acquaintances/interactions reactive capabilities pro-active capabilities

2013
Douglas S. Robertson William M. Lewis Peter M. Sheehan Owen B. Toon

[1] The Chicxulub asteroid impact produced massive extinction in terrestrial environments most likely through an intense heat pulse and subsequent widespread fires. Aquatic environments were shielded from this heat and fire but nevertheless showed massive extinction in marine environments and, for reasons unexplained, far less extinction in freshwater environments. Extinction in marine environm...

1998
C. N. Dahm

1. The surface water/groundwater (SW/GW) interface is a crucial control point for lateral nutrient ̄uxes between uplands and aquatic ecosystems and for upstream/ downstream (longitudinal) processes in lotic ecosystems. 2. Hydrological and biogeochemical dynamics of the SW/GW ecotone are linked to the degree of channel constraint and the sediment characteristics of the ̄oodplain and stream bed. 3....

Journal: :Environmental toxicology and chemistry 2013
Taylor A Jones Matthew M Chumchal Ray W Drenner Gabrielle N Timmins Weston H Nowlin

Methyl mercury (MeHg) is one of the most hazardous contaminants in the environment, adversely affecting the health of wildlife and humans. Recent studies have demonstrated that aquatic insects biotransport MeHg and other contaminants to terrestrial consumers, but the factors that regulate the flux of MeHg out of aquatic ecosystems via emergent insects have not been studied. The authors used exp...

2014
Simon J. Thuss Jason J. Venkiteswaran Sherry L. Schiff

Stable isotopes ([Formula: see text]15N and [Formula: see text]18O) of the greenhouse gas N2O provide information about the sources and processes leading to N2O production and emission from aquatic ecosystems to the atmosphere. In turn, this describes the fate of nitrogen in the aquatic environment since N2O is an obligate intermediate of denitrification and can be a by-product of nitrification...

2014
Martin Wagner Magnus Engwall Henner Hollert

(Micro)Plastics in the aquatic environment are an issue of emerging concern. However, to date, there is considerable lack of knowledge on the abundance and toxicity of plastic debris in aquatic ecosystems, especially with regard to the freshwater situation. In this editorial, we briefly discuss important aspects of the research on environmental (micro)plastics to stimulate research and call for...

2000
Ronald Benner Mary Ann Moran Robert E. Hodson

The relative contributions of procaryotes and eucaryotes to the degradation of the lignin and polysaccharide components of lignocellulosic detritus in two marine and two freshwater wetland ecosystems were determined. Two independent methods-physical separation of bacteria from fungi and other eucaryotes by size fractionation, and antibiotic treatments-were used to estimate procaryotic and eucar...

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