Post number 4

My microorganism, is a lichen a mutualistic organism of fungus and algae. While it may live in most areas Lichens do need a specific environment to survive. Algae alone don’t have a waxy cuticle like plants, so they are unable to retain water during drought periods that was until the introduction of fungal hyphae into the system allowing them to absorb liquid water and water vapor. When Lichens are wet or in a moist area they are on and photosynthesizing and actively growing while when they are dry are turned off. This is known as poikilohydry allowing lichen to turn off its photosensitive machinery and conserve energy. You can tell if a lichen is in the on form based on its color.

Lichen also needs clean air to exist and survive. In the industrial age specifically being sensitive to Sulfur dioxide which can quickly degrade the fungal thallus of the lichen. Notice how most cities don’t have lichen (or at the very least a less diverse amount of lichen) just algae on the trees at best. This can make lichen a great indicator of pollution. For example bushy lichen needs cleaner air, leafy can survive a little bit of pollution while crusty lichen (like Canoparmelia texana ) can survive air pollution.


Like all living things lichen needs nutrients to exist like O2, CO2, H2O and especially nitrogen. While Lichen needs nitrogen, it can’t normally access it in its current state so that where other microorganisms step in like the to make it usable. The cyanobacteria in the lichen can be used to fix the nitrogen so it can be actively used by the lichen. Other than that CO2 and O2 are obtained through other normal algal functions


Finally, is the physical location lichen lives or the substrate. Many lichens can grow on rocks trees and the soil itself. This combined with its as poikilohydry abilities allows it to grow and survive in multiple diverse locations and even change the habitat such as sand dunes allowing other species to colonize the area. The Shield Lichen I found was located on top the trees of Arabian mountain and can be found throughout the


My microbe is once again Canoparmelia texana or shield lichen found in Arabia mountain Georgia. One strange quirk of my microorganism is that as a lichen is a symbiotic organism of both fungi and algae with an asexual and sexual phase. The lichen’s life begins when the fungal mycobiont grows around an algal photobiont and cyanobacteria. The fungal part forms most of the structure creating the thallus or main body structure of the lichen and envelopes it with hyphae (it may even penetrate it). Next comes 3 forms of growth and reproduction a lichen may take. Which is listed as follows

  1. Vegetative or where the thallus just grows which is slow.
    1. For my microbe the growth rate is about 0.5mm- 0.5m but it lives for a relatively long time of 500-5000 years.
  2. Asexual reproduction by releasing tiny fragments of itself in 3 ways
    1. Fragmentation- older thallic portions break off
    2. Sorida- spherical bundles of filaments
    3. Ishida- tiny finger like projections                                                       
  3. Sexual reproduction which involves
    1. The male, flask shaped sex organ the Spermogonium which produces spermatia from small pores or ostioles inside the sex organ                                                              
    2. The female sex organ or Carpogonium which is a stalk like projection with the lower coiled ascogonium and upper tricoghyne                                                                                                   
    3. Finally, the spermatia enter the tricoghyne and fertilizes the ascogonium and starts a new thallus growth

The lichen lifecycle can be seen in the following youtube video

Canoparmelia texana Shield lichen general structure

My organism is Canoparmelia texana is a form of lichen that I found during my trip to arabia mountain. Lichen is a symbiotic organism consisting of a algal and fungal layer. First there is the cortex or outer layer of the lichen thallus protecting the rest of the organism. The upper cortex is made up of fungal hyphae of the upper fungal layer and below that is the algal layer aconospores in a lacunar shape, these conida spores are the primary zone of reproduction for the lichen. Closer to the basement layer is the large medulla hyphal layer filled with the Canoparmelia texana fungus. Next the more congested lower cortex hyphal layer and finally the black apothecia Rhizines. Pictures of sample

Day one

I ventured to Arabia Mountain park on a quiet weekday. There wasn’t a lot of people there since it was well 2:00pm and when I tried to talk to a worker she wasn’t exactly qualified for this work to study the tree Lichen known as Canoparmelia texana “shield lichen,”. Canoparmelia texana is a strange whitish growth dust around the base of the tree after the recent rain shower this a algae (protist) fungi symbiotic complex on the bark of the tree. Three things that drew me to this microbe was one it’s ubiquity, two how often its ignored despite this, and finally it’s pollution tolerance which means if spread can help to protect the environment (in small ways). Now how I choose this microbe, no real logical thought, it was either this or mushrooms and unfortunately, I could not find any. Pictures below.                                                                                                                   

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