In 1972, the United States legislature passed the Clean Water Act due to a crisis in the nation’s water purity. The purpose of the act was to restore the chemical, biological, and physical nature of our nation’s waterways that had been so damaged by pollution.

The goal of the act was that, by 1985, no more pollutants would be discharged into the water supply and all of our nation’s rivers, streams, and lakes would be fishable and swimmable once more. Every city was required to install a water treatment plant, and every industry was required to use the best available technology to limit the amount of pollutants that entered water sources (Outwater, 1996). Under these stringent demands, water quality began to improve slightly. Still, almost two decades after the year of supposed goal fulfillment, about a third of the nation’s waterways continue to be polluted. Read more

Arctic ice-melting this summer has already been so extreme that it has easily passed the last record low, set in 2007.

Sea ice cover in the Arctic has fallen to its lowest level since satellite records began 33 years ago, scientists said recently, prompting experts to warn the world had entered “uncharted territory” in the rate of climate change.

But as the annual summer melting period ends, scientists at the National Snow and Ice Data Center in Colorado said the Arctic’s sea ice “extent” – the total area that is at least 15 per cent ice – had fallen to just 3.41m square kilometres, or 1.32m square miles. This is nearly 50 per cent lower than the average recorded from 1979 to 2000 and well below the September 2007 record low of 4.17m sq km, leading some to warn that the climate may be changing faster than previously forecast. Read more

All water on a surface of our planet forms an environment named as hydrosphere. The hydrosphere occupies the biggest part of its surface: more than 380 million km2, or more than 75 % (its general area is about 510 million km2).

The characteristics of hydrosphere is usually begun from figure of 361,2 million km2 that is claimed to be the area of the surface of the Earth that is covered with water. But that is only the area of the seas and oceans, and all hydrosphere occupies larger territory. Read more

Researchers Expect Warming Waters to Shrink Fish Size by 20% by 2050

An important study published September 30, 2012 in Nature reveals:

The size of aquatic water-breathers is strongly affected by temperature, oxygen level and other factors such as resource availability2, 14. Specifically, the maximum body weight ( ) of marine fishes and invertebrates is fundamentally limited by the balance between energy demand and supply, where is reached when energy demand = energy supply (thus net growth = 0).

What this means in practical terms is that as the oceans get warmer fish are expected to get smaller. Much smaller. Body weights are expected to shrink by 14 to 24% between 2000 and 2050. Tropical waters will be affected most, with an average fish size reduction of more than 20%.

One of the excellent illustrations in the Nature study showing the decline in fish size as related to warming of the oceans.

Researchers from the University of British Columbia used computer modeling to study the effects of changes in the ocean and climate systems on 600 species of fish. The study’s lead author, William Cheung, emphasized that he and his colleagues were “surprised to see such a large decrease in fish size.” Fish in the tropics, who are smaller-bodied, are especially affected by warmer ocean temperatures and will migrate to regions that are now temperate or even to polar ones. Read more