Casino Creek. Macroscopically, the specimen in this sample appeared as a large bright 

 green mass of filamentous algae. Microscopically, the mass proved to be a monoculture of 

 Cladophora, probably Cladophora glomerata, a common filamentous green alga (Division 

 Chlorophyta) that often becomes a nuisance in nutrient-rich lakes and streams in temperate 

 regions around the world. The bright green color indicates fresh new growth; epiphytic diatoms 

 had not yet had a chance to colonize the filaments. 



Cottonwood Creek. Macroscopically, the specimen in this sample appeared as a pale 

 yellow to beige flocculent mass about 1 centimeter thick and several centimeters wide and long. 

 Microscopically, the mass proved to be a colony of diatom (Division Bacillariophyta) cells 

 embedded in amorphous mucilage. The cells were mainly a Cymbella species and a Synedra 

 species. These taxa are known to extrude polysaccharide mucilage through pores in their cell 

 walls, thus forming stalks, tubes, and amorphous masses in which the diatoms live. Certain 

 species of Cymbella and Synedra are associated with eutrophication. 



Non-Diatom Algae (Beaver Creek) 



In addition to diatoms, which ranked first in biovolume at all three sites, periphyton 

 samples fi-om Beaver Creek contained cyanobacteria, red algae, green algae, and yellow-green 

 algae (Table 3). At the upper site, the pollution-tolerant cyanobacterium Oscillatoha was 

 fi-equent and ranked 2"'' in biovolume. The filamentous green alga Cladophora was common and 

 ranked 3"^ , while the filamentous red alga Audouinella was occasional and ranked 4'*^. 



At the middle site, Cladophora and Oscillatoria were common and frequent and ranked 

 2" and 3"^ , respectively, followed in abundance by Vaiicheria and two genera of green algae: 

 Oedogonium and Closterium. The chrysophyte Vaucheria prefers steady flows of cool water and 

 is often found in springs and spring brooks. At the lower site, Cladophora was abundant and 

 ranked 2" in biovolume, followed by an occasional cell of Closterium, which ranked 3"^. 

 Cladophora is frequently cited as an aquatic nuisance in the United States (Wehr and Sheath 

 2003). Large standing crops of Cladophora are of^en a sign of elevated concentrafions of 

 inorganic nutrients, particularly phosphorus. 



