An ecosystem is generally defined as the union of the biological community and its habitat. The community (the biotic) and the habitat (the abiotic) are intimately connected in a reciprocal relationship. As an example of this reciprocity, consider that physical factors shape the environment in which the beaver lives, while the beaver fundamentally changes the physical world in which it lives.

The term was first proposed in print in 1935 by A. G. Tansley, who wrote:

The more fundamental conception (than biotic community) is, as it seems to me, the whole system, including not only the organism-complex, but also the whole complex of physical factors -- the habitat factors in the widest sense."
Since its conception, the ecosystem concept has had a fundamental role in guiding ecological and environmental research. It has led to a great deal of interdisciplinary research, as biologists, chemists, geographers and geologists realize that their domains overlap and connect in a fundamental way in nature. Much of the recent theoretical work performed in ecology approaches whole ecosystems, rather than populations or communities by themselves.

One of the principal characteristics of the ecosystem is its scale-dependency. There are small (water-filled holes in tropical trees) and large (the boreal forest) ecosystems, the latter encompassing the former. Recent research has been focussed on not only modeling energy flux in these ecosystems, but understanding how different scales relate to one another. The rates at which biotic and abiotic reactions occur are directly related to the scale of the ecosystem, and the importance of one component to another is related to their similarity in scale. For example, climate changes (which affect ecosystems at a slow rate) have intense impacts on the forests but very little on the microbial communities living in the soil.

The ecosystem concept has also greatly changed the basic philosophies behind the management of natural resources. Classical approaches considered only the impact a development would have on the elements in question (for example, how a mine might affect the local walleye population -- a popular sport fish). Currently, developers and government agencies consider the role a development will play on all the elements of the ecosystem. The assimilation of ecosystem theory into management practices has changed the nature of environmental protection laws from prophylactic to preventative.

Build Your Own Ecosystem!

It happens once in a while after watching too much National Geographic Channel that you start hearing your inner voice screaming "Ooh, ecosystem. I want one!" over and over until it gets annoying. Now I doubt you can buy your own ecosystem from Wal-Mart, so let's follow the logic stemming from the Heckscher-Ohlin model: if it's more expensive to buy it outside, make one at home. While it can be very tempting to build your own Amazon Forest, I strongly discourage it. Let's be realistic here, a contained environment is easier to control than an open one. Imagine the Biosphere 2 or the Eden Project, only smaller. Much much smaller. Ready?

In the beginning...
when you decided to make make your own ecosystem... you didn't have an earth that was void and formless. Don't feel bad, we'll create one.

To make your own formless enclosure, you will need:

To form the frame for the bottom glass, cut two 12 1/2-inch lengths of the wood strip, to go across front and back, and two 10 1/2-inch lengths for the ends. Glue these to the particle board base with all-purpose white glue. The strips should butt against each other at the corners. Squeeze a bead of sealer around the inside bottom of the frame formed by the wood strips, then set the bottom glass inside the frame. Next, squeeze a bead of sealer around the bottom glass next to the wood-strip frame. Stand the front, back, and end pieces of glass in this sealer, securing them temporarily at the corners with small strips of cellulose tape. Front and back pieces should overlap end pieces.One by one, separate each corner; apply sealer on the edges of glass that will overlap; press the corner back together, and reattach the temporary tape. Remove the temporary tape once the sealer has set, then apply permanent waterproof weather-strip tape around the corners from bottom to top of the tank, letting it lap over the inside about 1/4 inch. Apply tape around top edge of tank, cutting it so it can be folded over to the inside. Squeeze a full bead of sealor along all inside joints, and smooth it into a cove shape using your finger.

Now you have an empty container to hold your ecosystem. You need to fill it up with water to give your "mighty current" something to sweep. But first, allow your eco-tank to set for 48 hours. Then put it in a location where you can always view it, preferably, away from direct sunlight. Add a layer of peat moss at the bottom, and cover it with 2 inches of dark substrate. After that, fill it with distilled water. Let your water stand for another 48 hours (to let any remaining harmful chemicals evaporate).

Let there be light!
While waiting for the standing time, buy a 400W Radium Metal Halide Lamp with 20K color temperature for your miniature world. Don't ask why. Just buy it! And while you're at the store, buy an overhead aquarium filter.

Let there be a firmament above...
Okay, a firmament is quite too much. Just set the filter up and switch it on to make the water flow and start a good gas exchange. Great! Now a mighty current is sweeping through the waters of your formless world. Now that your filter is working, install the halide lamp, and switch the lamp on as well. Keep your environment like this for 24 hours.

Let there be a Nitrogen Cycle...
Let's not keep your world empty. An ecosystem is not an ecosystem without life forms. Start a bacteria culture. First, turn the lamp and the filter off. Then, add fish food into the water. The water should become cloudy. Let it sit for 8-12 hours before adding 1 teaspoon of ammonia. Run the filter and let some bacteria thrive inside your filter. Wait for about a week then introduce aquatic plants to your system. When selecting water plants, choose those that are good oygenators and capable of thriving in acidic environments; because that's what we're making, an acidic world. If you don't believe me, check your water's ph, it should be close to 7.

Put fertilizer into the water and give your plants time to settle (two weeks should be enough). After this, the nutrients in the water and the intense light will encourage the growth of algae. Don't be alarmed; it's natural. We'll get rid of them. In the mean time throw in a slate rock, a driftwood (hey! boil the driftwood first) and a small unwaxed terracotta pot.

Let there be invertebrates!
Introduce 2 red ramshorn snails and 1 Japanese swamp shrimp (Yamato numa ebi) and watch them graze on your algae field.

Let the water team with an abundance of living creatures!
Okay, since this is a freshwater ecosystem, you can't put an octopus in. However, you can start stocking it with beautiful tetra. In the first week, add neon tetras (in a group of 8). They will probably be shy at first, and will try to hide behind the driftwood or among the plants. But give them time. Feed them regularly (with blood worms) and watch them as they grow more and more comfortable to your acidic environment. Introduce cardinal tetras (maybe about 5) after the first week. Give them time to become familiar with their environment. Then after a couple of weeks, add rummy nose tetras and blue king tetras both in groups of five. I think that's enough fish in your world.

The idea behind this project is to witness interdependence inside an enclosed environment. Ideally, the light should stimulate your plants to make carbohydrates, absorb carbon dioxide and release oxygen into the water (you know, photosynthesis). Your invertebrates should take nutrients from the aquatic vegetation and some decaying matter, as well as keep your tank free of algae. The fish should not only release carbon dioxide and take the oxygen in, but also release ammonia for the microbial life; your bacteria should then convert ammonia to harmless compounds which your plants could make use of. But where will the fish get nutrients from? Unless you could raise a colony of tubifex worms or start a sustainable daphnia culture, you would have to feed the fish yourself.

Ah you're done. Now all you have to do is watch your very own ecosystem burst with life (and sometimes, death). Congratulations! You are now an ecosystem builder. But it doesn't end there. You should keep and eye on your system and maintain it, otherwise it will disintegrate. Always check the water temperature, ph level (keep it close to 7), and CO2 level. Once a week, change 10 perecent of the water in your tank. If you live in a country with four seasons, it is imperative that you install a heater to keep your creatures warm during the winter. There are many other things you should know about maintaining your ecosystem, but I won't tell you. I think I've already shared enough so let experience teach you the rest.

Log in or registerto write something here or to contact authors.