User:William Jessup/Notebook/Biology 210 at AU

Algae and Protists in the Hay Infusion 07.02.15

Introduction: Out of all the Eukaryotes, the two major groups of unicellular organisms are algae and protists. Algae perform photosynthesis, converting light energy into chemical energy. On the other hand, protists consume nutrients to produce energy. Both unicellular eukaryotes have multiple lineages and a wide variety of species that fall under their kingdom. The goal of this experiment was to observe and identify the protists and algaes that are living in our transect. These organisms are very important to biodiversity because they are often the base of the food chain, supporting all of the organisms later in the chain. The photosynthetic protists also help to produce oxygen, which is consistently consumed by many organisms.

Methods: First, two wet slides were prepared from samples from two different niches (Top and Bottom) in the Hay Infusion. The slides were observed on 10X and 40X objective lenses and any algae or protists were identified using a dichotomous key. After identifying several protists, we shook up the hay infusion and prepared a serial dilution. In order to this, we took 50μL of the Hay Infusion mixture and added it to 5mL of sterile broth creating a 1:100 dilution (10^-2). 50μL of the 1:100 dilution was then added to another tube of 5mL of sterile broth, making a 1:10,000 dilution (10^-4). This process was repeated two more times to produce a 10^-6 and a 10^-8 solution. Additionally, a total of eight nutrient agar plates were set up, four of which had tetracycline added. One of each type of plate was labeled the following: 10^-3, 10^-5, 10^-7, and 10^-9. For each plate, 50μL of a specific solution was added. 50μL of 10^-2 solution were smeared on the both of the 10^-3 plates. 50μL of 10^-4 solution were smeared on the both of the 10^-5 plates. 50μL of 10^-6 solution were smeared on the both of the 10^-7 plates. Finally, 50μL of 10^-8 solution were smeared on the both of the 10^-9 plates. All of the agar nutrients plates were then placed off to the side for the incubation. See image below for more details.

Results: After sitting out for two days, the Hay Infusion turned a milky white color, with some sediment laying on the bottom of the jar. A greenish brown film was also starting to grow on the top of the mixture. The solution smelled like dirt or mud and very swampy.

Only three organisms were found and identified. At the bottom of the Hay Infusion, only one organism, Colpidium, was found while at the top two other organisms were found, in addition to more Colpidium. The following table examines key characteristics of of each organism:

Organism	Type	Size (μm)	Location with Hay Infusion	Count	Motility
Colpidium	Protizoa	30	Top and bottom	A lot everywhere	motile
Pandorina	Green Algae	50	Top only	A lot everywhere	Very motile
Actinosphaerium	Protizoa	25	Top only	2 total	Very slow moving

Of the organisms discovered, only the Pandorina was a photosynthesizing eukaryote. The other two consume nutrients produced elsewhere.

Discussion: For some reason, only three separate organisms were identified in the Hay Infusion. This could be in part to the soil sample that was take. Perhaps it was just a bad sample. However, it could also mean that there is a poor biodiversity for protists and algae in our transect. If the Hay Infusion were to continue growing for two or more months, I would expect for the food supplies to slowly decline resulting in a decline in protist population. Eventually I would expect all life within the jar to die. Selective pressures that could affect the life in the jar is the amount of food and sunlight reaching the jar.

Establishing a Transect 06.30.15

Introduction: A transect is an established section of a habitat or ecosystem that is typically monitored for biodiversity. Biodiversity, the number and type of species found in a region, is so important because it increases the opportunity of medical advances, economic development, and biological resource discovery. By studying a specific transect, we can estimate the biodiversity and health of other ecosystems with similar environments. The purpose of this experiment is to analyze the biodiversity of a transect on the campus of American University.

Methods: To establish a transect, we walked to the Woods-Brown Amphitheatre and found a lush area (20x20 m2) with a small stream flowing through it. We walked around the area and looked for any abiotic and biotic factors we could find without disturbing the environment. We collected soil samples from a couple different locations in the transect for the hay infusion. To make the hay infusions, we added ~10g of the soil sample to 500mL of distilled water and 0.1g of dried milk. The solution was mixed and placed by a window without the lid on.

Results: The transect we found was on a hill with a small stream flowing through it. On one side there was a sidewalk and on the other was the McDowell residence hall. The area had several trees and smaller shrubs, as well as tall grasses and ferns. We also observed several species of birds, including American Robins and a Common/European Starling that were drinking from the stream. Abiotic Factors:  Rocks  Sidewalk  Water (manmade stream)  Dirt  Sprinkler head  McDowell Hall

Biotic Factors:  Plants (Ivy, ferns, tall grass, trees, etc.)  Birds (American Robin, European Starling, House Sparrow, Gray Catbird, unidentified)  Insects (ants, gnats)  Crustacean (Armadillidiidae/ Pill Bug)

Discussion: There was a large variety of both Biotic and Abiotic factors that were observed in the transect. Although some of the plant and animal species were unable to be identified properly at the time, we got a good idea of the variety of living organisms in the area. It will be interesting to see the actual species count because not only is American University is a certified National Arboretum, but our transect falls directly on a designated wildlife habitat, so it should potentially have numerous plant and animal species.