Wednesday, July 25, 2012

Let’s Talk Science: Breaking down decomposers

By Brook Beeler, environmental educator, Office of Communication and Education

Nitrogen and phosphorus are essential building blocks for living organisms. These elements and others, like carbon, allow organisms to create cells, tissue, and provide energy to complete their life processes. Nitrogen and phosphorus, also known as “nutrients”, are an integral part of living organisms. These nutrients continue to be important to the ecosystem even after the organisms die. If it weren’t for an essential part of the food web known as decomposers these nutrients would forever be trapped in dead plants (like lawn clippings and dead leaves) and animals.

Decomposers, like the ones pictured in this simplified aquatic version, are an important part of the food web. They break down dead organisms and release nutrients like nitrogen and phosphorus for other organisms to use.
Decomposers, such as fungi, bacteria, and invertebrates like earthworms and insects, work to break down the cells and other structures that made up any living organism. Watch this short video that shows how decomposers are nature’s “trash collectors”. In the process of breaking down dead plants and animals, decomposers do two important things:

1) They use oxygen to gain energy and drive their own life processes.
2) They release nutrients back into the environment for other organisms to use.

Understanding these two functions of the decomposer might just help with the bigger picture. Because when you insert human behaviors into the system we can have a big impact on the outcome.

Nutrient pollution

Nutrient pollution is a well documented problem in our waters in the US. You can learn more about it from this short EPA video. Nutrients can directly make their way to waters in a variety of ways including stormwater runoff. When these nutrients hit a lake or river, they act as a fertilizer, accelerating plant and algae growth. It is when the plants and algae die that decomposers step in to do their job.

So as decomposers kick their cycle into high gear, remember they are 1) using oxygen and 2) releasing more nutrients back into the environment. As they consume the oxygen in water there is less available for fish and other aquatic life. Low oxygen also means that some bodies of water may not meet Washington’s water quality standards.

Yard waste can create pollution

Remember the example of grass clippings and dead leaves? These happen to be great food for decomposers. As they break down dead plant tissue, they are freeing nutrients, which in turn make great food for your yard and garden. However, often times this yard waste is improperly disposed. Dumping grass clippings near storm drains, into ditches, and even directly into water can add up to a big nutrient pollution problem. You can learn more about proper disposal of grass clippings from our Focus on Clean and Healthy Waters.

One person’s yard waste may not make a big difference, but when many people do it, the decomposing yard waste can be very harmful to water and fish. So keep yard waste away from streams and lakes. Here are a few other ways that you can prevent nutrient pollution in your local lake, river, and Puget Sound.
You can learn about these and many other ways to protect our water at our Washington Waters website.

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