Diatoms Tell History of Johns Creek

SHELTON (October 28, 2004) –The Squaxin Island Tribe is studying diatoms – tiny one celled organisms – from the wetland source of Johns Creek to discover how the stream has changed over the past few decades. “Different types of diatoms take root under different conditions,” said John Konovsky, water quality manager for the Squaxin Tribe. “By studying which diatoms were prevalent in the past we can determine how the habitat has changed.”

When diatoms die their shell-like bodies stay intact and settle to the bottom of the wetland, so researchers can not only see what current habitat conditions are but also how they have changed over time. Tribal researchers will canoe through the creek’s upper wetlands, taking 4-foot core samples along the way. Those 4-feet can take the tribe back decades into the creek’s history.

Compared to higher forms of life, such as insects or fish, diatoms give a much clearer picture of what has been going on in the creek. “Fish eat bugs, so it’s easy to say that if there are a lot of different kinds of bugs, that fish would also be healthy,” said Konovsky. “But, diatoms are much more precise than that.”

“The assumption is that lower levels of life respond more readily to environmental changes,” said Konovsky. “Diatoms aren’t focused on one aspect of habitat, they respond to everything we throw at them.” For example, if the temperature of the wetland increases, the type of diatom that can exist will quickly become more prevalent than other species. This can tell the tribe that something, like a drought or an unusually hot summer occurred, and had an impact on the creek.

The tribe’s diatom study is part of a larger investigation of habitat conditions on Johns Creek. Last fall the tribe mapped water temperatures on several streams, including Johns Creek, using infrared technology. So called “Forward Looking Infrared Radar” allows researchers to find hotspots in surface water temperatures and gives them access to the full picture of water temperature throughout the stream.

Unlike most major river systems in western Washington that have glacial or mountain sources, practically all of the streams in the tribe’s traditional fishing area originate in wetlands. “Johns Creek is pretty typical of the kinds of streams we see,” said Konovsky. The more the tribe looks into the unique way that these streams behave, the better they can prevent them from being degraded. “We’re developing a way to determine the biological health of these wetlands.”

Coho salmon, which spend a much longer time in fresh water as juveniles than other salmon, have especially been affected by habitat degradation. “Protecting and restoring habitat is the most important thing we can do to recover declining salmon populations,” said Jim Peters, natural resources director for the Squaxin Tribe.


For more information, contact: John Konovsky, water quality manager, Squaxin Island Tribe, (360) 432-3804. Emmett O’Connell, South Sound information officer, (360) 438-1181, ext. 392, [email protected]

Photos available: Photos of Squaxin tribal staff gathering diatom samples available, high quality, jpg format. Contact Emmett O’Connell at above number for more information.