TIDAL ZONES
Tidal zones are unique environments. Not quite land, not quite sea, the inhabitants of tidal pools fight to survive between two worlds. Tatoosh Island, located off the Washington Coast, is one of the richest temperate tidal systems in the world.

Bob Paine, a University of Washington zoologist, has visited Tatoosh at least 12 times a year for over 30 years to study the natural connections between the organisms that inhabit the intertidal zones.

An on-going experiment Paine conducted with mussels and starfish since 1970 was ideal in demonstrating the principal of "keystone species," which holds that certain species are critically important to the balance of an ecosystem.

Bob Paine discusses how all organisms are embedded in one rich, interactive system.

Paine's experiment showed that the population of starfish in the Tatoosh tidal zone are critical in controlling the mussel population. In test areas where Paine physically removed the starfish, mussels crowded out most other life forms. Thus, the starfish is a "keystone species" because it has a critical effect on the entire ecosystem. Without the starfish, the biodiversity in the tidal zones of Tatoosh Island would be radically different.

Keystone species apply to plants and trees as well. Destruction of a certain tree or plant can also alter the characteristics of an ecosystem. Scientists understand how two or three species' affect each other but the complex relationship of a whole ecological community is still not completely understood. If human activity accidentally decimates or completely destroys a keystone species in an ecosystem, the imbalance could mean the environment could change drastically forever.

Visit www.rtpnet.org/~nhas/virtvoy/keystn.html to find out more on keystone species

To find out ways to help keep our tidal zones in balance, visit: http://www.kingcounty.gov/environment/waterandland/puget-sound-marine.aspx

Now let's visit the temperate
forests of Washington to understand
the important role of trees
in the Earth's biodiversity!