Ruth Patrick, stream biologist pioneer, dies at 105

Dr Patrick was an ecologist who worked at the Academy of Natural Sciences for 8 decades. She died Monday at the age of 105. Dr. Ruth Patrick devised a system to gauge the health of a stream by studying the biological diversity in it. She was an expert on diatoms (single celled organisms) and discovered that the presence or absence of diatoms, certain insects and macro invertebrates were all indicators of stream health. Ruth Patrick was the first person to realize that we can measure the extent to which conditions have affected a stream by observing the number and type of organisms living in it and relating that information to the surrounding habitat. In order to determine the richness of the living community, scientists observe changes in the total number of organisms. Different species react to pollution in different ways. Organisms that are pollution-sensitive are more susceptible than others to the effects of changes in a stream. Organisms that are pollution-tolerant can cope with adverse conditions more easily. The presence or absence of such organisms is an indirect measure of pollution. When a stream becomes polluted, pollution-sensitive organisms decrease in number or disappear, while pollution-tolerant organisms remain stable or increase in number. We can thank Dr. Ruth Patrick for this discovery. For more information about Dr. Patrick’s life, check out the memorial article about her at: http://www.ansp.org/about/academy-news/archive/2013/September/ruth-patrick/