Lichens are a symbiotic relationship between algae and fungi
that cover ten times as much of the surface of earth as tropical rain forests.
The fungi are not able to survive without their algal partner and the algae may
survive off the photosynthetic properties. Lichen species differ by the fungi
present and allows for classification. The lichen body is composed of fungal
filaments that encompass green algae cells. Even when there is a low
concentration, lichens are able to absorb minerals and water. This synergistic
system can withstand intense cold, heat, light and barren rock.
Lichens are significant in determining air quality of an
area because of growth sensitive to pollutants. Namely, air pollutants such as
sulfur dioxide and nitrogen dioxide. Sulfur dioxide is considered an industrial
pollutant and is commonly the by-product of high sulfur fuels; nitrogen dioxide
is a common oxide produced by high temperatures in combustion reactions
including the burning of coal of fumes from automobiles. Nitrogen dioxide cause
alkalinity in lichen substrates while sulfur dioxide disrupts important
physiological processes in lichens and can cause acidity. “Lichen deserts,”
areas of little to no lichen growth, occur in areas where there are high sulfur
dioxide concentrations. This is because photosynthesis and respiration is
sensitive to changes in pH and therefore sulfur dioxide rich areas show a
decrease in lichen species. On the other hand, a tolerant species has the
potential to grow in areas of high pollutant concentrations.
Beatrix Potter, a well-known children’s author, had a
passion for botany. She was one of the first to anticipate lichens as symbiotic
life forms with records of algal and fungal properties. Potter took the
initiative to maintain some algal cells and fungal spores in the heart of her
own kitchen. Illustrations demonstrated Potter’s observations suggesting that
every twenty minutes fungal and algal growth was monitored. She was forty years
ahead of her time with many of the fungal differences not recognized until the
1940s.
Candelaria concolor,
a yellow foliose species, contains small lobes and is tight attached to the
substrate on which it grows. This species favors nutrient rich bark and is
sensitive to sulfur dioxide. Physica
species, typically blue or green in color, are abundant if excess nitrogen is
in the air. If one of these species is present in an area that is not normally
this nutrient rich, the site is considered to be anthropogenically enhanced.
I was put into group B and we covered West Green and the
Union Street area. I chose a tree just outside the Life and Sciences Research Building
just off Union Street. The tree was very close to the parking lot at only a
twelve-step distance. To measure the lichen growth, a four-quadrant contraption
was created out of a piece of 11x17 inch paper; each quadrant measured 4x4
inches. The four directions were measured on the tree: north, east, south, and
west. This data is going to be used to determine sulfur dioxide and nitrogen
dioxide levels in the air on different areas of the campus. This data will
include samples from trees on South Green, College Green, and West Green/ Union
Street.
The coordinates of my tree on West Green: 39°19’38, 0’N 82°06’15.3’W. I identified
the species as Acer rufinerve, a
snakebark maple that is native to Japanese mountain forests; the tree exhibited
the paired branching. To begin, the measuring device was placed about 1 meter
off the ground (close to 3 feet) and held at almost eye level. The northern
side of the tree contained the most lichen with a measured 3 in all four
quadrants. This was the side where the colonies were visible from across the
parking lot with the naked eye. The eastern side of the tree demonstrated the
lowest measurement of lichen. Quadrants one, three, and four had a score of 0
while quadrant two had a score of 1. The southern direction of the tree also
contained many lichen with scores matching the northern direction. All four
quadrants measured a 3. It was difficult to see just how many lichen were on
this side because the colonies were so small, however, abundant. These would
not have been visible across the parking lot unlike the lichen facing the
northern direction. The western direction of the tree was fairly moderate with
quadrant one measuring a 3 and quadrant 3 measuring a 1. Quadrant two and
quadrant 4 measured a 0.
The standard deviation of the data was then calculated.
Values:
1.
N: 3, 3, 3, 3
2.
E: 0, 1, 0, 0
3.
S: 3, 3, 3, 3
4.
W: 3, 0,1, 0
Average:
(3+3+3+3) + (0+1+0+0) + (3+3+3+3) +
(3+0+1+0) = (12 + 1 + 12 + 4) = 29
29/ 16 values = 1.8125 or 1.81
average
Standard Deviation:
N: 3 – 1.81 = (1.19)2 = 1.41
|
S: 3 – 1.81 = (1.19)2 = 1.41
|
3 – 1.81 =
(1.19)2 = 1.41
|
3 – 1.81 =
(1.19)2 = 1.41
|
3 – 1.81 =
(1.19)2 = 1.41
|
3 – 1.81 = (1.19)2
= 1.41
|
3 – 1.81 =
(1.19)2 = 1.41
|
3 – 1.81 =
(1.19)2 = 1.41
|
E: 0 - 1.81 = (-1.81)2 = 3.28
|
W: 3 – 1.81 = (1.19)2 = 1.41
|
1 - 1.81 = (-.81) 2 = .66
|
0 - 1.81 = (-1.81)2 = 3.28
|
0 - 1.81 = (-1.81)2 = 3.28
|
1 - 1.81 = (-.81) 2 = .66
|
0 - 1.81 = (-1.81)2 = 3.28
|
0 - 1.81 = (-1.81)2 = 3.28
|
Average:
√(1.41 + 1.41 + 1.41 + 1.41) + (3.28 +.66 + 3.28
+3.28) + (1.41 +1.41 +1.41 +1.41) + (1.41 + 3.28 + .66 + 3.28)/ √16-1
=√(5.64) + (10.5) + (5.64) + (8.63)/ √15
=√30.41/15
=√2.023
=1.42
The standard deviation of the data
was calculated to be 1.42.
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| Tree location |
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| Tree location |
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| Paired branching |
 |
| Paired branching |
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| Northern direction |
 |
| Northern direction |
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| Eastern direction |
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| Southern direction |
 |
| Western direction |
Sources:
