David Schindler is an ecologist and limnologist — an expert on the science of inland waters — who proved that phosphates in detergents used by humans act as a pollutant that ultimately leads to the death of ecosystems in lakes. He was also able to establish that acid rain causes the widespread death of fish.
Agricultural and urban runoff enters lakes, raising nitrate and phosphate levels and leading to algal overgrowth and oxygen depletion. Changes in acidity levels can reduce the diversity of wildlife, killing sensitive species. To demonstrate just some of the effects of human pollution, David famously carried out an experiment where he separated a lake into two then treated one side with carbon, nitrogen and phosphorus, and the other with carbon and nitrogen alone.
An aerial photograph of the results clearly showed the bright-green bloom of algae that grew on the phosphorus-treated side, whilst the untreated side remained clear. This photograph attracted global media attention and helped to raise public awareness of this important environmental problem — triggering the banning of harmful phosphates in detergents.