Melosira - Part of the Chrysophyta or golden-brown algae, Chrysophyta are divided into two classes. Chrysophyceae and the Bacillariophyceae. Melosira falls into the class Bacillariophyceae which are diatoms. Commonly found in drinking water, can give the water a grassy or fishy odor. (Burglingame, 2002)

Oscillatoria - cyanobacteria, Filamentous organism without heterocysts, Able to convert nitrogen into ammonia, nitrates, or nitrites. Found in the bottom of the aquarium. (Palinska, 2007)

Reference:

Canter-Lund H, Lund J. Freshwater Algae – Their microscopic world explored. Bristol. Biopress Ltd. 1995. p. 141, Fig. 255 Melosira. p. 227, Fig.430 Oscillatora

Burlingame, Gary. "Algal Blooms—Impact on Treatment, Taste, and Odor Problems." Encyclopedia of Environmental Microbiology. Vol. 1. New York: Wiley, 2002. 204-213. 6 vols. Gale Virtual Reference Library. Gale. Univ of Tennessee Library Serials Dept. 20 Nov. 2010 
<http://find.galegroup.com/gvrl/infomark.do?&contentSet=EBKS&type=retrieve&tabID=T001&prodId=GVRL&docId=CX2847500032&source=gale&userGroupName=knox61277&version=1.0>.

Palinska, Katarzyna, William Horgan, and Wolfgang Krumbein. "Cyanobacteria." Encyclopedia of Life Sciences: Supplementary Set. Vol. 22. Chichester, United Kingdom: Wiley, 2007. 199-206. 6 vols. Gale Virtual Reference Library. Gale. Univ of Tennessee Library Serials Dept. 20 Nov. 2010 
<http://find.galegroup.com/gvrl/infomark.do?&contentSet=EBKS&type=retrieve&tabID=T001&prodId=GVRL&docId=CX3026300160&source=gale&userGroupName=knox61277&version=1.0>.