Susan Williams, Ph.D.

Intertidal Ecology of Fucus, San Juan Island, Washington

• Map: Map of our study sites
• Sites: Table describing each site's physical features
• Graphs- Page 1, Page 2: Sample graphs illustrating some of the temperature data
• Data: Links to downloadable temperature data from each site
• Contact information for the principle investigators

Sample Intertidal Temperature Graphs:

Midnight vs. Noon Daily Temperatures

In the San Juan Islands, at any given point on the rock, the total number of hours per day of exposure to air remains fairly constant throughout the year (ca. 50% of the time at the High level, 22% at the Mid). However, the timing of the lower low tides swings from daytime in the spring and summer to after dark in the fall and winter, and this change is clearly reflected in the TidbiT data.

Maximum vs. Minimum Daily Temperatures

Graphs illustrating daily maximum and minimum temperatures differ slightly from those comparing Noon and Midnight.

Mean Maxima for High and Mid Tidal Heights

Mean maxima through the year are illustrated for the hottest and coolest sites, showing very similar seasonal patterns but substantial differences in the degree of heating. Davison Head (DH) was a south-facing site and Point Caution (PC) was north-facing. As expected, TidbiTs in the High zone consistently recorded hotter temperatures than in the Mid zone.

A few sites (e.g. Hannah Heights,) had Mid zones that were as hot or slightly hotter than the adjacent High zone; these data reflected the Mid TidbiT's placement on a more-horizontal or a more-south-facing surface than the High one.

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