Today as we observed the ecosystem we noticed the leaves have completely died and are disintegrating on top of the soil and on the sides of the ecosystem. We believe the top half of our ecosystem are dying because a few weeks ago our string connecting the plant to the water disintegrated. There are sill roots connecting down into the water however I do not think the plant was receiving enough nutrients. Our soil also looks dry so the plant is not receiving nutrients from the soil. Roots that had been sticking out on the top half of the ecosystem are now withering because they did not find any nutrients. This also shows that the plant is dying.
Elodea is still alive and thriving. We think it is still thriving because it has water, nutrients from the water, and sunlight. Possibly the elodea is still living possibly because it was able to anchor itself into the pebbles creating a stable environment.
There are still baby snails attached to the walls and elodea. Our first snail looks to be dead however our water is not cloudy allowing the other organisms (elodea and other snails) to still survive.
Condensation changed from primarily one side of the bottle to the entire bottle. The condensation has also moved down into the lower half of the ecosystem.
After the first week of our observation we never observed the daphnia. We do not know if they were living in the rocks where we could not see them or if they died.
Some questions we have is the difference between having a closed ecosystem verses putting holes in the top half of the ecosystem for oxygen and another source of energy. This would be interesting to see the differences. Another variation we considered was leaving the ecosystem in a bottle outside in the sunlight rather than inside near the window. Finally, creating ecosystems of different proportions could show students that ecosystems can thrive in any space with the correct sources.
One other variable I was considering how it affected our ecosystem was the seasonal change. Even though the plant was inside, it still went through a seasonal change with cooler weather, cloudiness, less summer sunlight.
Another variable we may look into is the type of soil we used and how much soil we used. Our plant died due to lack of nutrients so if we had begun with more soil I am curious if the plant would have thrived for a longer period of time.
I am curious if the elodea will eventually die as well because the ecosystem rotation may fail due to the plant dying, or can the elodea survive off other sources of nutrients.
We can also try using different organisms. We feel the daphnia was a little useless because we were not able to observe or collect any data. One organism we feel would be an asset to the ecosystem would be a worm. It could help fertilize the soil creating more nutrients for the plant which was what we say having trouble surviving.
I think this could be a good activity to bring to the classroom. It could last for a long period of time and our students would see it on a more daily basis than we were able to here in this class. It would be a wonderful hands on activity for students learning about ecosystems, organisms, and each role sources play in an ecosystem.