FRESHWATER AND MARINE ALGAE

Cyanobacteria - Second lecture -  Ecology, Water Quality, Aquaculture

Nitrogen fixation - Need lots of energy to break N=N (N₂ triple bond) uses ATP from photosynthesis and nitrogenase enzyme.  N₂ is converted to NH₄⁺  which is then converted to glutamine which is transfered to vegetative cells.  Most N fixation is in heterocycsts, but can also occur in some non-heterocytous cyanobacteria under low dissolved N conditions.
Most interesting case is Azolla-Anabaena symbiosis.  Important to rice cultivation.
Many organisms benefit from cyanobacteria ability to fix N and photosythesize.  Symbiosis is common.

Azolla - Anabaena
Rhizosolenia (Diatom) - Richelia
Sponges - Aphanocapsa
Tunicates - Prochloron
Fungi - Nostoc and others
Roots of cycads - Nostoc
Polar bear hairs - Aphanocapsa or Gloeocapsa

Fungi and algae = lichens   about 10% have cyanobacteria others are green algae

Cyanobacteria can survive in extreme environments
hot springs to 74 degrees C
under polar ice caps  - Lyngbya and Phormidium
high alkalinity - Lake Texcoco in Mexico - Spirulina
high salinity - coral reefs
open ocean - Synechococcus and Trchodesmium (makes the Red Sea red and seen by Darwin on Beagle, looked like sawdust in water)
desert soils - cryptogramic crust (Nostoc and Microcystis)

only acidic waters slow cyanobacteria

Water quality

indicators of eutrophication - Annie, Fanny and Mike  - Anabaena, Aphanizomenon, Microcyctis
form large mats on bottom and floating
several cause off-flavor, Geosmin and MIB, problem in drinking water and fish
catfish farming
Phoenix Project
can also release toxins (hepatoxins - Microcystin) and neurotoxins and Lyngbyatoxin (swimmers itch)

Aquaculture

Spirulina - Wonderfood, collected in Lake Chad and Lake Texcoco, now grown in raceways
grown as feed ingredient (chickens and ornamental birds and fish, seafood,
Cyanotech and Earthrise farms
SuperBlue Green algae on the Internet - Oregon's Lake Klamath