Review the effect of acid rain on the local distributions of

Humans produce about 160% of the natural emissions of sulphur. This is compared with about 5-10% in the case of carbon dioxide and nitrogen (Krebs, 2001). Combustion of fossil fuels, according to Krebs (2001) has ‘altered the sulphur cycle more than any of the other nutrient cycles’.

Sulphur is quickly oxidised in the atmosphere to sulphate (SO4) and redeposited rapidly on land or in the oceans. One clear manifestation of this alteration of the sulphur cycle is the widespread problem of acid rain (Krebs, 2001).

In areas uncontaminated by either industrial emissions or calcareous dust, precipitation usually has a pH value close to 5.0 (Schindler, 1998). Distilled water, which contains no carbon dioxide, has a neutral pH of 7.0. Liquids with a pH less than 7.0 are acid, and those with a pH greater than 70 are alkaline (USGS). Uncontaminated rainfall usually has a slightly acidic pH because it contains small amounts of both weak and strong acids of natural origin. In most areas within several hundred kilometres of industrial emissions prec

Schindler (1998) ends one part of his paper by saying; ‘Although it is now clear that reducing emissions of SO2 will allow the rapid recovery of lakes, it is unlikely that original pH values will be reached for many years. Unassisted biological recovery of all original species also appears to be unlikely…It therefore seems prudent to prevent as much ecological damage as we can’.

Special cells in the gills of fish, called ionocytes or chloride cells, control the concentration of chemicals in the blood. They collect ions such as chloride and sodium from the water, and transfer them to the blood where they must be kept at higher concentrations. Changes in these cells seem to be one way by which acidification affects fish populations (Swenson and May, 1987).

As a summary it is clear that acidification affects both fish and invertebrates, directly and indirectly. Some species have a higher tolerance to acidic environments than others, and some organisms within a population have a higher tolerance than others within the same population.

Some topics in this essay:
Sodium Chloride, According Krebs, American European, United Kingdom’, , Cloche Mountain, USGS Uncontaminated, USGS Schindler, swenson 1987, Washington DC, schindler 1998, eilers 1987, University Wisconsin, krebs 2001, fish populations, acid rain, lake trout, ph 70, brook trout, 50 schindler 1998, sulphur cycle, acidification affects fish, acidification water moves, streams rivers lakes, lower trophic levels,