Tuesday, October 25, 2011

Favorite Lake

My favorite lake growing up was Lake Michigan because my friends and family would up up to the Indiana Dunes on the southern shore of Lake Michigan. There are huge sand dunes to climb up as well as a beautiful beach to lay and play on. We would even go up some saturdays with a group of people from church and clean up the beach area. I still go up to the Indiana Dunes when I see my friends during the summer.

Indian Mounds Lab-Decomposition of Leaf Litter

Decomposition of Leaf Litter

Decomposition is the process of converting dead organic matter into simpler and smaller compounds. This is the main source of nutrition for trees within the forest. The main products from complete decomposition are carbon dioxide, water, and inorganic ions (like ammonium, nitrate, phosphate, and sulfate). Insects, worms, bacteria, and fungi carrry out these processes at the surface of soil and underneath the soil surface. Temperature and soil moisture affect the rate of decomposition since this process is carried out by bacteria and fungi. The higher the temperature, the higher the rate of decomposition. Decomposition still does occur even under the snow. If soil moisture is low, decomposition is inhibited from bacteria and fungi drying out. Also, decomposition is slow in wet soils because anerobic conditions occur which are shorter than aerobic conditions.

Leaf litter decomposition can be measured by the litter bag technique. A pre-measured quantity is placed within the mesh bag which is placed within the litter layer of the forest floor. The bags can be measured of time to determine the amount of mass lost from decomposition. They are allowed to be exposed to normal temperature and moisture fluctuations while being decomposed by insects and microorganisms.


Friday, October 7, 2011

Negative Feedback Loop-Blood Sugar Levels

Blood Sugar Level Change

The body maintains a blood sugar concentration (blood glucose level) between 64.8 and 104.4 mg/dL. The amount of glucose (sugar) found within the blood is the blood sugar concentration. The body regulates the blood glucose level in order to sustain a metabolic homeostasis. Glucose provides most of the body's energy for the cells in a body. Glucose moves from the intestines or liver to the body cells through the bloodstream and is able to be absorbed into the cells through the hormone insulin, which is produced through the pancreas. Blood glucose levels fluctuate throughout the day, usually be lowest in the morning before the first meal and rise after meals for an hour or two. Levels outside the normal range of blood glucose levels are indicators of medical conditions such as hypoglycemia and hyperglycemia.

After eating a meal, the level can rise to 140 mg/dL for non-diabetics. Insulin cause cells in the body to take up the glucose from the blood. It is necessary to have insulin to remove the excess glucose since it can be fatal to have too much glucose. So blood sugar levels go up once you have eaten since there is a high amount of glucose or sugar coming into the body. Insulin begins to kick in to take up the glucose in order to lower the blood sugar levels and bring the body back to a homeostatic state.

Blood sugar levels being controlled by insulin can then be considered a negative feedback loop since the increased effect of insulin prohibits an increase in the blood sugar levels. The goal is to get back to homeostasis or below. To make the system become normal again.

Time                       Blood Sugar Level
  0                                      104
  5                                      145
  10                                    180
  15                                    185
  20                                    132
  25                                    120
  30                                    108
  35                                    105
  40                                    104
  45                                    105

Monday, October 3, 2011

Soil Lab

The 12 Soil Orders

The twelve soil orders include:
1) Gelisols
2) Histosols
3) Spodosols
4) Andisols
5) Oxisols
6) Vertisols
7) Aridisols
8) Ultisols
9) Mollisols
10) Alfisols
11) Inceptisols
12) Entisols

Each soil is unique in the nutrient levels and where it is located in the world.

The soil I think is most interesting is Oxisols. Oxisols is a very weathered soil. You can find it in intertropical regions of the world. They are rich in Iron and Aluminum minerals and deficient in most other minerals. Globally, Oxisols only take up approximately 7.5% of ice-free land area. Hawaii is the only place in the U.S. where this soil can be found-approximately 0.02% of land area in U.S. There is low fertility within this soil but this can be compensated with treatments of lime and fertilizers. There are five suborders within the type Oxisols: Aquox, Torrox, Ustox, Perox, and Udox.

For the lab last Monday, we discussed the soil in the community garden behind Centenary United Methodist Church by Mercer in Macon, GA. They have set up a community garden for people to be educated on food and gardening, create a network for people in the local food system, and support and sustain food system in the Macon area by celebrating local food culture. Mark Vanderhoek from Mercer University is one of the main leaders of the Macon Roots organization.

In our lab, we took a split-spoon corer sample which gives you a soil profile. This allows you to see the depth of the soil and the type of soil the further you go down in depth. The change of color of the soil as well as the change in texture of the soil can be seen telling you about the type of soil and change of soil type over time.

We also took soil sieves which is a type of sifter that has stacks of mesh/grate over the bowls to allow sample of soil to be sorted out to see the different types of soil. The bigger holes in the mesh/grate are at the top and the grate gets smaller as you go down. The larger grains of soil are clay. The middle sized grains are silt and the small-fine grains of soil are sand. You can decide what type of soil it is through the percentages of clay, silt, and sand within the soil sample. This is found through the Soil Texture Diagram.

Lastly, we used the Dichotomous Key for Soil Samples to determine the classification of a soil sample we collected. Our group found our soil to be a Loamy sand because it remained in a ball when squeezed and it did not form a ribbon of uniform thickness and width when pressed between the thumb and forefinger.