User:Megan Piccirillo/Notebook/Biology 210 at AU

Lab 2: Identifying Algae and Protists
Objective: To examine algae and protists from our transect, to understand the characteristics of algae and protists and to practice using a dichatomous key to identify species (Bentley, 2015).
Introduction: This week we examined unicellular eukarya from samples taken from our Hay Infusion, which was prepared the week prior. The goal of the lab was to identify at least three organisms from the "top" of our Hay Infusion and three organisms from the "bottom" of our Hay Infusion, to ensure that we captured organisms that grow and live in different niches. I hypothesized that the organisms found at the "top" of our Hay Infusion would be different from the organisms that were found at the "bottom."

Hay Infusion culture jar: Sample taken from the "top," or the surface and from the bottom of the jar.

Materials and Methods: We observed the undisturbed Hay Infusion sample through vision and smell. Next, we prepared two wet-mount slides in order to examine the algae and protists present in our sample. To do so, we used a pipette to draw a specimen from the very top surface of the samples and a specimen from the bottom of the jar. To view the organisms, we used a microscope with magnification ranging from 4x to 40x. To identify the particular organisms found, we used a dichotomous key. In order to measure the organisms, we used the microscope's ocular lens.
Observations and Data:
Description of the Hay Infusion: The smell of the sample was rancid and fowl. None of us could bare the smell and there was obvious mold growing on the surface of the, which appeared to have hardened. The bottom of the sample appeared to contain decomposed matter and was almost mud or sand-like. The water within the sample was murky and appeared yellow-brown in color. Of the plant matter that has been placed into the Hay Infusion sample last week (a small Brussels sprout, two pine needles, and a small leaf), only the pine needles appeared intact.

Another view of the Hay Infusion culture jar

Found Organisms:
From the top of the jar, the following organisms were found;
- Pelomyxa (2mm and motile)
- Paramecium aurella (130 μm and motile)
- Pandorina (colony size: 45 μm and non-motile)

From the bottom of the jar,the following organisms were found;
- Gonium (colony size: 90 μm and non-motile)
- Clopidium (61 μm and motile)
- Paramecium aurella (140 μm and motile)

A picture of a paramecium aurella observed through a microscope

Conclusion: From the observed data, my hypothesis that there would be different organisms found in the sample from the "top" of the Hay Infusion compared to the organisms found at the "bottom" of the Hay Infusion is not entirely supported. Both niches contained paramecium aurella, and therefore the organisms were not completely different based on the niche. Perhaps paramecium aurella can survive in various niches or perhaps the difference in the "top" and "bottom" of the jar was not too significant. If I were to redo the experiment, I might test chemical properties of the different niches or identify more than 3 organisms from each niche to see if there is more crossover.
Source: Bentley, M., Walters-Conte, K., and Nancy K. Zeller. 2015. A Laboratory Manual to Accompany: General Biology II. Department of Biology, American University: Washington D.C.. 22-23.

Lab 1:
Objective: To make careful observations about the characteristics of different species (Bentley, 2015).

Introduction: In order to achieve the above objective, I have observed a 20x20 ecological niche. My niche is located in the back of campus behind the “North side” residence halls. It is a relatively low traffic part of campus, as people do not regularly travel through the area to get to work, class, or their homes. The transect is part of a community garden on American University’s campus in Washington, DC. Within the transect, there are 4 wooden planters, each containing a different species of vegetation. I hypothesis that the soil/ground sample collected from the community garden will contain many species because of the varied factors within this niche.
Materials and Methods: To complete these observations, my group members and I walked to the transect and took notes using a pencil, paper, and a Smartphone’s camera (pictures below). We spent about 15 minutes collecting visual observations and also collected a soil/ground specimen using a 50mL conical tube. The specimen collected from within the 20x20 transect was used to conduct a Hay Infusion. Completing the Hay Infusion involved combining 500mL of water with 10-12g of the soil/vegetation/fecal specimen in a jar. 0.1g of dried milk was added to the mixture and mixed gently for 10 seconds. The jar was left unopened for a week to allow Protista to grow (Bentley, 2015).
Observations and Data:
The abiotic factors include:
• Direct sunlight, as there is no vegetation or constructed object to provide shade
• Frozen soil, due to recent temperatures
• Frost and ice on the plants, due to recent weather and temperatures
• 4 constructed 3x6 rectangular vegetation planters
• Fence: the area is fenced in, which provides protect from larger animals that may eat the growing vegetation

The biotic factors include:
• Woodchips surrounding the vegetation boxes
• Dried out grass and weeds surrounding the vegetation boxes
• Animal feces
• Decomposing plant matter in and around the vegetation boxes
• Vegetation variation of the planters (kale, cucumber, lettuce, and Brussels sprouts)

Conclusion: Based on our observations, there are many biotic and abiotic factors that influence this 20x20 niche. While I could visibly see multiple species of vegetation, I could not observe multiple species of bacteria or protista without a microscope. Next lab, we will use the Hay Infusion sample to look at organisms from out transect under the microscope. Perhaps, we will identify more species. MP
Sources:
Bentley, M., Walters-Conte, K., and Nancy K. Zeller. 2015. A Laboratory Manual to Accompany: General Biology II. Department of Biology, American University: Washington D.C.. 16-17.