week 7 - 2/25/2010 Cyanobacteria (blue-green algae or...

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2/25/2010 1 Cyanobacteria (blue-green algae or Cyanophytes) Prokaryotes (no membrane bound organelles) Most are O 2 producing photosynthetic Found in most habitats Oldest known fossils Cheney Reservoir, Kansas. June 2003. Photo Courtesy of KDHE. http://ks.water.usgs.gov/studies/qw/cyanobacteria/ Cyanobacteria Specialized cells akinetes – resting cells Heterocytes (heterocysts in old literature) – site of most nitrogen fixation Float by gas vesicles (surface scums) Phycobilins – unique light harvesting pigments Can produce toxins http://ks.water.usgs.gov/studies/qw/cyanobacteria/binder-lake-ia.jpg Photo by J. L. Graham http://www.mfe.govt.nz/publications/ser /snapshot-lake-water-quality- nov06/html/images/cyanobacteria.jpg Cyanobacterial Morphologies Fig 8.4 Heterocytes in Anabaena sp. www.micrographia.com/. ../bact0200/anabae03.htm
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2/25/2010 2 Phycobilins (alga – bile) Accessory pigments that absorb light in the red , orange , yellow and green light, wavelengths which are not well absorbed by chlorophyll a The bluish pigment phycocyanin is found in Cyanobacteria and gives them their common name of " blue-green algae ". The reddish pigment phycoerythrin is found only in Rhodophyta and gives them their common name of " red algae Blooms of cyanobacteria http://www.waterencyclopedia.com/images/wsci_01_img0017.jpg Microcystis a type of cyanobacteria, secretes a toxin which causes liver damage in animals including humans. (Photo by Tom Bridgeman, Univ. Toledo, courtesy of Ohio Sea Grant) http://www-cyanosite.bio.purdue.edu/images/lgimages/microcy3.jpg Cyanobacterial toxins Produce hepatotoxins and neurotoxins (anatoxins, microcystins…) Toxins can be bioconcentrated by some organisms Toxins evolved as protection against zooplankton grazing Other types of algae make toxins (red-tide) http://www.gov.mb.ca/waterstewardship/quality/images/Toxic%20Algae.jpg http://www-cyanosite.bio.purdue.edu/cyanotox/toxiccyanos.html Read Sidebar 8.2 page 134 Protoctista Eukaryotic Algae Protozoa http://media.wiley.com/Lux/75/8375.nfg026.jpg
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2/25/2010 3 Protoctista (protists) (Greek protos , very first; ktistos , to establish) • is defined by exclusion: its members are neither animals (which develop from a blastula), plants (which develop from an embryo), fungi, nor prokaryotes All the other Eukaryotes: Algae (other than cyanobacteria), protozoa (Protista), amoeba, … Have nucleus (eukaryotic), single celled or multi-cellular Eukaryotic Algae have nucleus Non vascular Oxygenic Photosynthesis (chloroplasts – Chl a ) Single celled, colonial, multicellular Prokaryotic Cyanobacteria (blue-green algae) Generally not considered “true” algae Do not have membrane bound organelles Protoctista Eukaryotic algae : nonvascular, eukaryotic, oxygen photosynthesis, chlorophyll a Rhodophyceae (red algae) Chrysophyceae (golden algae ) Bacillariophyceae (
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This note was uploaded on 11/14/2010 for the course NRM 2305 taught by Professor Staff during the Spring '08 term at Texas Tech.

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week 7 - 2/25/2010 Cyanobacteria (blue-green algae or...

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