Thomas Robert Soderstrom Thomas Robert Soderstrom Thomas Robert Soderstrom (9 January 1936 Chicago – 1 September 1987) was an American agrostologist His special field of study was the grass family Gramineae or Poaceae. He was Curator of Grasses at the National Museum of Natural History in Washington, DC for some twenty years. In 1957 Soderstrom graduated from the University of Illinois with a BSc in Biology, and enrolled at the graduate school at Yale University, earning a Master of Science in Biology the following year and a PhD in Botany 1961. He joined the National Museum in 1960 as assistant curator. He became
Organisms involved in water purification to improve as the protozoa are subsequently consumed by rotifers and cladocera. Purifying bacteria, protozoa, and rotifers must either be mixed throughout the water or have the water circulated past them to be effective. Sewage treatment plants mix these organisms as activated sludge or circulate water past organisms living on trickling filters or rotating biological contactors. Aquatic vegetation may provide similar surface habitat for purifying bacteria, protozoa, and rotifers in a pond or marsh setting; although water circulation is often less effective. Plants and algae have the additional advantage of removing nutrients from the water; but some of those nutrients