Science Of Lichens

After we discovered that Skerries is an unpolluted town with green lichen, we decided to find out if Balbriggan was polluted or unpolluted. We discovered that the lichen found in Balbriggan tended to be more orange and red as opposed to Skerries's green and white. This tells us that Balbriggan is a polluted town.The orange and red lichen can grow when there are high levels of pollution in the air as they are more resilient than the green lichen. The lichen that we found in Balbriggan were mainly orange and red and we searched mainly for lichen on trees. Balbriggan has high levels of pollution because they have quite a large population. There are lots of factories in Balbriggan so they produce many fumes. Balbriggan is a fairly large town so people tend to drive places rather than walk. This releases lots of fumes from cars and pollutes the air.

Lichen do survive extreme conditions. They are found in some of the most extreme places on Earth – the frozen north, hot deserts, rocky coasts. They are common as epiphytes on leaves and branches in rain forests and temperate woods. They can live on bare rock, walls and gravestones, and on exposed soil surfaces.There are about 200 different kinds of lichens in Antarctica. In the Horlick Mountains, at 86 degrees south, there are six different kinds of lichen. In the Himalayas, they grow at altitudes up to 18,000 feet (~5500m). The European Space Agency discovered that lichen can survive unprotected in space. Two species of lichen were sealed in a capsule and launched on a Russian Soyuz rocket. Once in orbit the capsules were opened. Two species of lichen were exposed to the vacuum of space, to cosmic radiation and huge swings of temperature. After 15 days the lichens were retrieved and were found to be in full health: no damage was found.

Lichens  on  trees  are a unique organism because they are actually a symbiotic relationship between two organisms — fungus and algae. The fungus  grows  on the  tree  and can collect moisture, which the algae needs. The algae, in return, can create food from the energy of the sun, which feeds the fungus. Lichen on tree bark is completely harmless to the tree itself. The rhizines (similar to roots) allow them to attach to the tree but do not go deep enough to harm the tree in any way. Many people believe when a tree becomes sick and has lichen, that the lichens are the cause of the illness. This is impossible and most likely the lichen was there long before the tree became ill.

Many animals  eat lichen , including snails, voles, squirrels and snub-nosed monkeys. In winter, they are an important source of food for reindeer, which avoid the ones containing poisonous cyanobacteria.  A  large number of related  lichen  species that the reindeer and caribou  eat  are known, depending on which continent they inhabit, as reindeer  lichens  or caribou  lichens . Cladina stellaris is the most heavily eaten species. Caribou  prefers  eating lichen  because it is very healthy. Musk-oxen live in the frozen Arctic and roam the  tundra  in search of the roots,  mosses , and  lichens  that sustain them.   Humans  sometimes  eat lichens  too, and some species are used in Asian traditional medicines. Only a few  lichens  are truly  poisonous , with species of Letharia and Vulpicida being the primary examples. These  lichens  are yellow because they have high concentrations of the bright yellow toxin vulpinic acid. Wolf  lichen  (Letharia vulpina) was used in Scandinavia

During the course of our project, we at Ardgillan C.C and Skerries C.C discovered that the lichen found in Skerries tend to be more green and white than orange and red. This tells us that Skerries is a not very polluted town. The green lichen can only grow when there are low levels of pollution in the air. The lichen that we found in Skerries were mainly green and we searched mainly for lichen on trees. Skerries has low levels of pollution because they have a relatively small population. There are no factories in Skerries so they don't produce many fumes. Skerries is a fairly small town so people can walk to places so there is not a lot of pollution from cars.

Think of lichen as a traffic light. RED/ORANGE lichen indicate heavy pollution in an area. This is when you should STOP and think about what you are doing to the environment. Just how you would stop at a red traffic light. If you see GREEN/WHITE lichen in your area,that means the environment is healthy and you should keepdoing what your doing, just like you would GO at a green traffic light.