1. Role of Microorganisms in Ecosystems Microorganisms are organisms that are ___ __________ ___ _____ with the unaided eye. Microorganisms can either __________ the health of an ecosystem or __________ the health of an ecosystem

2. Examples of microorganisms maintaining the health of an ecosystem 1. Some microorganisms are ________________, which means they can ____________ organic matter. Decomposers free up carbon, hydrogen, phosphorus, nitrogen, and other _____________ so that they can be re-used in the ecosystem.

3. Nitrogen Fixation 2. Microorganisms fix nitrogen, which is the process of changing _____ into _____. This is done so that plants can use the nitrogen for growth and development.

4. Mycorrhizae 3. ________________ is a type of fungus that forms a _________________ relationship with a plant. – The plant supplies the mycorrhizae with carbohydrates. The mycorrhizae allows the plant to _______________ more nutrients. – For example, some plants cannot absorb phosphorus. The mycorrhizae can access this nutrient and make it available to the plant.

5. Examples of microorganisms disrupting the health of an ecosystem 1.When a lot of nutrients come into an aquatic ecosystem, _________ _________sometimes form. The algae hogs the sunlight, causing most of the plants in the area to die. Bacteria enter the area to decompose the dead plants, which reduces the amount of _________ available for the other organisms.

6. Dead Zones 2. The lack of oxygen caused by the algal bloom creates an ___________ (low-oxygen) area. This is called a ___________ __________.