Blog Assignment #7: Biosphere

Gretchen Janes, Karina Yu, Megan Thees

Week 1: Immediately after making biosphere

Week 1

Week 6

• List of all the items that you added to your biosphere.

• Pond water
• Gravel
• Soil
• Anabaena (1.5mL)
• Selanastrum (1.5mL)
• Plants
• Bacopa caroliniana
• Ceratopteris sp. (water sprite)
• Subwassertang
• 1 big snail (Conrad)
• 3 small snails
• 1 shrimp (Stewart)
• 3 daphnia
• 2 large rocks
• ⅗ tube of Alga-Gro Concentrate

• Photo of another group's biosphere

Michelle, Eloina, Greyson, & Hazel’s Biosphere

• List of the items in the other groups biosphere
• Pond water
• Gravel
• Soil
• Anabaena (2.5mL)
• Selanstrum (2.0mL)
• Plants
• Bacopa
• Water sprite
• ¾ tube of Alga-Gro Concentrate
• 1 big snail
• 8 small snails
• daphnia
• 1 shrimp

Questions:

• Why did you choose to include the organisms that you put in your biosphere? What was your rational (i.e. more heterotrophs, equal heterotrophs to autotrophs, etc. and why)?
• For our biosphere we decided to put approximately an equal amount of heterotrophs to autotrophs to balance food and growth. We chose these organisms because each organism either complemented or controlled the growth of another. We added Anabaena because they can do nitrogen fixation which is good for the plants. And the plants control anabaena growth since it reduces algae population by providing shade and compete for the same nutrients. The plants are oxygenators. Snails and shrimps will control algae plant growth by eating the aquatic plants and algae. The daphnia can feed on unicellular algae such as selenastrum.
• What is the function/role or each of your organisms in your biosphere? What did you see them do?
• Plants: Plants control anabaena growth. The plants reduce algae populations by competing with algae for sunlight and nutrients. Plants are oxygenators.
• Anabaena: Does nitrogen-fixation which provides plants with usable ammonia.
• Daphnia: Controls selenastrum growth. Daphnia can feed on unicellular algae such as selenastrum.
• Snails: Control algae and plant growth. Snails eat aquatic plants and algae.
• Shrimp: Eats aquatic plants and algae.
• What changes did you observe in your biosphere over the last 6 weeks?
• All daphnia have died
• Discovered biosphere contained two newly hatched damselflies (currently in larvae state)
• Water has slowly gotten cloudy with green algae
• Were there any surprises?
• One surprise was finding two damselflies in our biosphere! At first we had no idea what they were but we knew we had not added them on purpose. Damselflies lay their eggs inside plant tissues and they spend a lot of their life living underwater so it’s interesting to see that the materials we were provided with could have had them. The damselflies could also have been living in the pond water that we added already.
• Would you expect your biosphere to continue to function/survive? Why?
• I would expect our biosphere to continue to function as it is now because the organisms that are left have the essentials they need to survive. The algae is obviously going well since the water is now cloudy with it. This means the plants are getting enough ammonium and the snails and shrimp are getting enough algae to eat. The plants may not get enough sunlight if the water gets progressively cloudier however if the snails reproduce this may solve that issue.
• Compare your biosphere to another group's biosphere? What are the similarities? What are the differences?  How do you account for the differences?
• We compared our biosphere to Michelle, Eloina, Greyson, & Hazel’s biosphere because we added similar items to both of our biospheres. We both added pond water, soil, gravel, 2 of the same plants (Bocapoa and water sprite), 1 shrimp, and 1 big snail. One of the major differences between the two biospheres was how many little snails were added. Our group only added 3 of them but the other group added 8. We were wondering if we had added more snails to our biosphere if the amount of algae would have been less, but looking at the other group who did add more snails the amount of algae looks about the same. However they did add more of the Alga-Gro concentration than we did, so maybe that evened it out in the end.  
• Reflection: What did the biosphere teach you about how ecosystems function?
• The biosphere taught us how important species interaction is to ecosystem functions. The flow/cycling of nutrients through the ecosystem, the regulation of populations, and the stability of the biological community, all contribute to the continuation and maintenance of life and this depends on their adaptation and coevolved relationships.
• Write at least 3 scientific questions based on your observations of your biosphere.
• What caused the daphnia to die?
• If more snails were added to our biosphere would the amount of algae be less?
• How did the two damselflies affect our biosphere?
• Write 1 hypothesis based on the questions above.
• If more snails were added to our biosphere and nothing else was changed, there would be less algae.
• Write an experiment your group could run to test the hypothesis above.
• Repeat our current experiment except this time we will add a total of 8 snails rather than just 4.