After some thought, they came up with an automatic sampler containing eight polyethylene bottles mounted on a carousel. Each morning the carousel automatically rotated to position the next bottle beneath the funnel. The sampler logged rainfall to within 0.2 millimetres as well as measuring the rate of rainfall in each shower. So successful were the samplers that they are now being manufactured and sold internationally under licence by Ecotech Ltd, a Melbourne-based environmental equipment company. Soils ain't soils Environmental response to pollutants depends on many factors.
Some regions cope with acidification better than others, having larger 'critical loads'.
Critical load refers to the greatest assault that an ecological system can withstand before showing measurable degradation. Scientists determine critical load by examining rock and soil type, land use and rainfall. If soil is fertile with a pH greater than 4.5, and rainfall is relatively low, the critical load will be high. The terrain can withstand moderately large additions of acidity without undue suffering. Conversely, in low pH soils, acidification mobilises toxic aluminium ions.