Blog Assignment #4: Mystery Pond Water Organisms

Gretchen Janes

Megan Thees

Karina Yu

Closterium found in water sample

Closterium on Pond Water poster

Epistylis from water sample, attached to
 root of the plant floating in the water. 

Epistylis on Pond Water poster 

Eremosphaeara from water sample

Eremosphaera on Pond Water poster

Describe the organisms that you found in your samples.

• Epistylis is a genus of peritrichous ciliates with a short oral disc, a collar and a rigid stalk. Sometimes they branch to form colonies, but the organism seen in this photo above is singular. This organism can attach to the skin or fins of a host, typically fish. Epistylis is of greater concern than other ciliates when in the presence of fish because it secretes protein eating enzymes that creates a wound on the host allowing for bacterial invasion at the attachment site.  
• Closterium is a genus of unicellular charophyte green algae in the family Closteriaceae. This is the closest unicellular organism to land plants. Closterium is a planktonic algae which provide food to zooplankton.
• Eremosphaera is a genus of green algae. It consists of spherical unicells. Each cell has numerous discoid, parietal chloroplasts with pyrenoids and lumps of starch grains that radiate outwards from the cell center in strands of cytoplasm.. A mucilage envelope is sometimes present. The cell wall of Eremosphaera is composed of numerous layers.

What organisms are they and what is their function in the pond system (autotroph, heterotroph, predator, food source for other organisms, etc.).

• We identified the organisms we found in our samples as Closterium, Epistylis, and Eremosphaera from the Pond Water Posters in lab.
• Epistylis are heterotrophs. This protozoan feeds on waterborne bacteria and particles. Epistylis are a food source for Amphileptus.
• Closterium are autotrophs. Closterium eat stentors and other larger protista. They use photosynthesis for food.
• Eremosphaera are autotrophs they use photosynthesis for food. They are a food source for certain fish, frog, and aquatic insects.

Did you find anything in the pond water that was unexpected?

• All of the organisms that we found were on the Pond Water posters in lab so it wasn’t unexpected to find them in pond water samples, but since we also looked at samples from the aquarium in lab it was a little surprising to see that that water was home to some of the same organisms!

REFLECTION: What did looking at pond water make you realize about the organisms that inhabit that niche?

• After looking at the water samples it made us realize that this niche of organisms is very contained in the way that ponds are usually landlocked and have no outflow, and the organisms that inhabit them essentially live there for their entire life span unless taken out by other organisms. It also made us realize the organisms are very diverse in this type of ecosystem.

QUESTIONS:

• If the organism were placed in a different aquatic environment would they adapt/survive?
• Where else can these organisms be found?
• How are these organisms distributed?
• Since different levels of light and things like oxygen are available at different depths of water in a pond, how different would the types of organisms found be from a sample from the surface of the pond compared to ones near the bottom?

HYPOTHESIS:

• These organisms can be found in any freshwater environment.

REFERENCES:

McCarty T. Pond Ecology (Water Quality). Water Quality (Penn State Extension). [accessed 2017 Apr 22]. http://extension.psu.edu/natural-resources/water/ponds/pond-management/pond-construction/pond-ecology