Report

A certain organism I found very interesting was the Closterium. This is the only the genus name for the organism. The scientific name for the organism is Closterium Moniliferum.(Mara). There were a great number of these in my microaquarium. The Closterium organism is “elongated cylindrical, often lunate unicells comprising of two symmetrical semicells. Single, axial chloroplasts with many pyrenoids in each semicell.” (NCBI). The Closterium has very noticeable vacuoles at each end of it with what appears to be crystals in them. In the Closterium, “Terminal vacuoles at the cell tips hold vibrating crystals of barium or calcium sulfate, the function of which are unknown. Brownian motion causes these microscopic particles to move erratically due to the impacts of collisions with the surrounding liquid molecules in which they are suspended.”(conncollege.edu). These crystally figures are what I found most interesting about the organism. Closterium is a placoderm desmid because the cell walls have pores to secrete mucilage, even though the cells are only slightly constricted in the middle compared to other placoderms. The cell wall may be smooth or lined by thin longitudinal striae or large pores that are visible with high resolution microscopy, and is sometimes yellow or brown in color. “Some species have extra sections in the cell wall called girdle bands. Polymers in the cell wall may help protect the cell from drying out and allow them to survive for months in environments such as the dried mud at the edges of lakes.” (conncollege.edu). They move by secreting a liquid out each end at separate times. This allows the organism to “somersault” around. (Nester). It therefore does not have flagella.

Domain: Eukaryota
Kingdom: Plantae
Phylum: Charophyta
Class: Zygnemophyceae
Order: Desmidiales
Family: Closteriaceae
Genus: Closterium
Specie: Moniliferum

The Closterium can reproduce either sexually of asexually. It reproduces asexually by budding from a partitioned parent cell, and reproduces sexually by conjugation to form a hypnozygote. (NCIB). Asexual reproduction by budding is a lot more common than sexual reproduction. If in fact reproducing sexually, Conjugation may occur between both morphologically mature cells and recently-divided immature cells. A conjugation tube is not usually present. Both cells split open at the middle to allow the gametes to move and fuse inside the empty walls. Some species may form spores. (conncollege.edu) Unfortunately, I could not find a drawing of its life cycle stages.






Mara D, Horan N. 2003. The Handbook of Water and Wastewater Microbiology. San Diego, Ca: Academic. 819 p.
Green Algae: Closterium. [Internet]. Connecticut: Connecticut College. [cited 2007 Nov 26]. Available from http://silicasecchidisk.conncoll.edu/LucidKeys/Carolina_Key/html/Closterium_Main.html
Closterium. [Internet]. Maryland: National Center for Biotechnology Information. [cited 2007 Nov 26]. Available from http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=34145