Microbial Communities using Hay Infusion Lab 9C

Microbial communities on a salt concentration gradient were measured over a period of 4 weeks. This is what was found:

1st measurement

Fresh-none

trace-1 moved

brackish- none

saline- 2 types everything moved-too many to count

high saline-2 types everything moved-too many to count

sea water- 1 type 3 cells

2nd measurement

fresh- 1 type of cell no movement

trace- 0 cells

brackish- 1 type 5 cells

saline- 1 type 4 cells

high saline- 0 cells

sea-  0 cells

3rd measurement-

Fresh-none

Trace-none

Brackish-none

Saline- 2 types,

High saline- 3 types

Sea- 3 kinds

4th measurement

Fresh-none

trace-none

brackish- none

saline- 1 type, lots of them

high saline- 3 types, lots of them

sea- 2 types, lots of them

Like Whittaker's study of trees, there is an ideal level where growth is most sustained. This is true for this experiment as well, high saline was most sustainable for growth, and anything less than saline was not good for growth. Although there may have been some incorrect measurements due to using the microscope wrong, the final result follows this hypothesis. 

Clements model for this experiment would say that certain species have a sharp cutoff on the level of salt tolerance in which habitat they can live in. This experiment seems to be more suited to the Gleason model, however, because some species were seen over several gradients of salt, although it was very obvious that their numbers declined in different salt habitats. 

The dried grass was collected from a salt marsh near the sea, but I would expect a different result from grass collected no where near the salt water, because the protozoas would not be adjusted to living in a salty environment. 

The collections smelled terrible:

Smell-

Fresh- bad breath

trace-horrible

brackish-better than trace

saline- same as brackish

highly saline- worse than fresh

sea- barely smell anything

The worst smelling sample had the most bacteria, however, the 2nd worst smelling one had no bacteria. Thus, we could not tell bacteria culture from the smell. However, it can be expected that many bacteria types grew in different hay cultures because of the different and unique smells, not to mention that we looked under the microscope at them.