Purpose

• Making an ecosphere jar that includes producers, consumers, (and decomposers).

Theory

   An ecosphere jar is a miniature ecosystem that does not need external resources. The plants (like algae) produce oxygen as a product of photosynthesis. Living animals (like snails, shrimps, or fish) breathe in oxygen and breathe out carbon dioxide and their waste contains nitrogen (both of which the plants need). The animals also eat algae and keep the ecosphere clean. Bacteria and other microorganisms eat the snail waste, decaying plants and helping the plants with carbon dioxide and inorganic nutrients that they produce as waste. The water continues to cycle inside the closed system through condensation. So, the whole ecosphere jar would have a full energy and matter cycle, and that means, this ecosphere jar can operate independently (except sunlight).

   I chose an aquatic ecosphere jar which included a bottle of water and soil. The water I used was sat for a day so that there would be some microorganisms and bacteria in the water served as decomposers. The soil I used was aquarium soil. It was made of natural soil as raw material by sintering, so it has natural detritivores that can provide nutrients for plants.

   The producer I chose is Ceratophyllum demersum. It is propagated by cuttings, so it is easy to keep it. I put two strains of it in my ecosphere jar. Although the more I put it in the jar, the more oxygen it would produce in the daytime, in the night, it would absorb more oxygen in the jar (certainly, it absorbs oxygen in the daytime as well, but in the daytime, it can produce oxygen and in the night, it does not produce any oxygen). Also, because my ecosphere jar is not very large, if I put a lot of producers in it, the space in which the shrimps lie would be too small, and they might get stuck in it.

   The consumers I chose were Neocaridina denticulata and Cipangopaludina chinensis. I put five Neocaridina denticulata and three Cipangopaludina chinensis. The shrimps are easy to keep because they only need water, a little bit of oxygen (rather than fish that need a lot of oxygen to live), and some aquatic plants to live in. Because Neocaridina denticulata donated feed on algae or organic detritus, it can help to remove residual bait, and algae, and can be mixed in the aquarium as a fish tank scavenger. Snails can purify water, avoid eutrophication, and decompose organic matter to improve the circulation of matter. Because my ecosphere is small, I did not put a lot of shrimp and snails in it, otherwise, the producer would be eaten up.

Steps

1. Put the soil in the jar and cover the bottom (about one-seventh of the whole jar).
2. Pour the water into the jar and fill it about two-thirds of the way.
3. Wait until the soil has settled and planted the aquatic plants in it. (The soil needs to cover part of the plants)
4. Wait until the water is clear and put the shrimp and snails in it. After that, pour the water into the jar that fills the bottle roughly with water.
5. Seal the jar and make sure no oxygen and any other matter can go into the jar.

Material

    A jar, a bottle of water, soil, two strains of Ceratophyllum demersum, five Neocaridina denticulata, and three Cipangopaludina chinensis.

Result

• After 30 days (11.7): All living things are alive.
• Now (2.22): Only the algae is still alive, which only one leaf left.

After 30 days, the consumers and producers are still alive, but the water becomes more cloudy than on day 1, and the roots of aquatic are coming out of the soil. Also, there are some small pieces of aquatic on the bottom of the water.

Analysis

    The organisms in my ecosphere jar are all alive after 30 days. I think the reason is the quantity distribution of producers, consumers, and decomposes is relatively even. The number of consumers is not too much that might eat all of the producers, the number of producers is not too much that take up all the space and the number of producers is not too little as well that can not provide enough oxygen. In addition, I put three snails in my ecosphere jar which can purify water, avoid eutrophication, and decompose organic matter to improve the circulation of matter. For the non-living things, I use aquarium soil which can provide nutrients for aquatics. Therefore, because of these reasons, my ecosphere jar could still be alive after 30 days.

    However, after 4 months, all consumers died, and the plant is dying. The reason I think is that consumers died and the balance between ecology is broken. So why the consumers died? I guess there are two reasons. One is those shrimps that were burned to death because of refracted by the sun. Another is the oxygen is gone. However, I don’t think that’s very likely because, in the end, the producer is alive (although there are only a few leaves on it). In short, because consumers are all dead, energy flows and matter circulates slower. There is not enough energy for snails to live, so snails died yet. Because there are no snails, organic matter produced by algae cannot be converted into inorganic matter. And thus, there are only a few leaves on the algae. From this experiment, I found that to form a perfect and healthy ecosystem, the conditions required are still very demanding. I still have some problems with the organisms I selected in the early preparation and the proportions of various organisms. So sorry about all shrimps and snails which died in this ecosphere jar. Rest in peace, all the way. I hope you will not enter the ecological bottle again in the next life, but enjoy the outside world.