Determining those changes in biomarkers that can be attributed to each factor is thus crucial for the correct assessment of the overall condition of aquatic environments, because ignoring environmental influence may lead to a biased image of pollution.
More stunning image galleries: Pollution from space, active volcanoes and a robot restaurant.
While popular perceptions of the east European environment center on nightmarish images of pollution hotspots, Communism also bequeathed a wealth of relatively untouched nature that supports far more biological diversity than can be found in Western Europe.
These unmanned crafts take photographs of smokestack scrubbers and assess smoke color in the images for pollution.
Thousands of images of pollution, strip mining, crowded cities, and land abuse could well be photographs taken in recent times.
The convention of coal companies grappled with these popular images: Air pollution and visibility, mine safety and labor regulations, unregulated strip mining, local apprehension, global warming, acid rain, soot and particulates, acid mine drainage and abandoned mines and more subsidence, the dreaded images of coal-draped Eastern Europe, and an unfair media.
In the West, at least, many observers see another image: massive air pollution and protesters hounding Olympic torchbearers.
Local technology companies are finding it harder to recruit employees, while business leaders fear that the city's image as the "pollution capital" is hurting its efforts to recruit companies and industries.
"The Great Stack, Sheffield" (1909), an etching by Joseph Pennell, shows smoke from a forest of chimneys blending and covering the sky — a memorable image of industrial pollution poisoning the atmosphere.
