نتایج جستجو برای: anthropogenic activity

تعداد نتایج: 1156982  

2012
Richard K. F. Unsworth Michael A. Rasheed Kathryn M. Chartrand Anthony J. Roelofs

There is strong evidence of a global long-term decline in seagrass meadows that is widely attributed to anthropogenic activity. Yet in many regions, attributing these changes to actual activities is difficult, as there exists limited understanding of the natural processes that can influence these valuable ecosystem service providers. Being able to separate natural from anthropogenic causes of s...

2017
Marcel Langner Thomas Draheim Wilfried Endlicher

Urban agglomerations are places of increased emissions of anthropogenic pollutants into the atmosphere. Since most of these pollutants are harmful to humans, reduction of their ambient concentrations is a major issue of environmental policy on international, national, and local levels. According to Wiederkehr and Yoon (1998), air pollutants can be grouped into major and trace or hazardous air p...

Journal: :Science 2003
Ben I McNeil Richard J Matear Robert M Key John L Bullister Jorge L Sarmiento

We estimated the oceanic inventory of anthropogenic carbon dioxide (CO2) from 1980 to 1999 using a technique based on the global chlorofluorocarbon data set. Our analysis suggests that the ocean stored 14.8 petagrams of anthropogenic carbon from mid-1980 to mid-1989 and 17.9 petagrams of carbon from mid-1990 to mid-1999, indicating an oceanwide net uptake of 1.6 and 2.0 +/- 0.4 petagrams of car...

Journal: :Environmental science & technology 2007
Etelvino H Novotny Eduardo R deAzevedo Tito J Bonagamba Tony J F Cunha Beáta E Madari Vinícius de M Benites Michael H B Hayes

The compositions of humic acids (HAs) isolated from cultivated and forested "Terra Preta de Indio" or Amazonian Dark Earth soils (anthropogenic soils) were compared with those from adjacent non-anthropogenic soils (control soils) using elemental and thermogravimetric analyses, and a variety of solid-state nuclear magnetic resonance techniques. The thermogravimetric index, which indicates the mo...

2016
Esther H. D. Carlitz Robert Miller Clemens Kirschbaum Wei Gao Daniel C. Hänni Carel P. van Schaik

Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwe...

Journal: :Environmental pollution 2002
B Koerner J Klopatek

Recent research has shown the Phoenix, AZ metropolitan region to be characterized by a CO2 dome that peaks near the urban center. The CO2 levels, 50% greater than the surrounding non-urban areas, have been attributed to anthropogenic sources and the physical geography of the area. We quantified sources of CO2 emissions across the metropolitan region. Anthropogenic CO2 emission data were obtaine...

2017
Ellie E. Dyer Phillip Cassey David W. Redding Ben Collen Victoria Franks Kevin J. Gaston Kate E. Jones Salit Kark C. David L. Orme Tim M. Blackburn

Alien species are a major component of human-induced environmental change. Variation in the numbers of alien species found in different areas is likely to depend on a combination of anthropogenic and environmental factors, with anthropogenic factors affecting the number of species introduced to new locations, and when, and environmental factors influencing how many species are able to persist t...

Journal: :محیط شناسی 0
عبدالرضا کرباسی دانشکده محیط زیست دانشگاه تهران شهرزاد ولوی کارشناس ارشد محیط زیست دانشکدة محیط زیست واحد علوم و تحقیقات اهواز

present survey studies intensity of heavy metals pollution (ca, fe, ni, cd, pb, zn, as, hg) in the sediments of bamdezh wetland. the main objective of the study is to quantify heavy metal pollution intensity in the wetland. other objectives of the study are separation of natural and anthropogenic heavy metal pollution and identification of the origin of heavy metals. results of this study shows...

Journal: :The Journal of experimental biology 2011
Dalal Hanna Gabriel Blouin-Demers David R Wilson Daniel J Mennill

Anthropogenic noise can mask animal signals that are crucial for communicating information about food, predators and mating opportunities. In response to noise masking, signallers can potentially improve acoustic signal transmission by adjusting the timing, frequency or amplitude of their signals. These changes can be a short-term modification in response to transient noise or a long-term modif...

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