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 Graphs: Photosynthesis, Air Temp and Humidity and H20 Loss

Figs. 1 & 2 BELOW. Rates of net photosynthesis of Fucus gardneri, a common intertidal seaweed, were measured to determine the variation in rates among individuals from two tidal heights at 14 sites around San Juan Island, Washington. Rates of 10 individuals (with few exceptions) were measured in air (to mimic exposure at low tide) and in water (submersed) and in both summer and winter at each tidal height at each site. The graphs represent the complete data set. Rates have been adjusted for seaweed mass (Analysis of Covariance), which differed significantly across tidal elevations. Some sites could not be sampled in winter due to difficulties of working at low tide at night. Site abbreviations: CCN (Colins Cove North), CCS (Colins Cove South), CPN (Cattle Point North), CCS (Cattle Point South), DH (Davison Head), FHL (Friday Harbor Laboratories), HH (Hannah Heights), LK (Lime Kiln), PC (Point Caution), PHE (Pump House East), PHW (Pump House West), RTN (Rueben Tarte North), RTS (Rueben Tarte South), SJC (San Juan County), WIL (Willows).

figure 1

figure 2

Figs. 3 & 4 BELOW. Air temperature and relative humidity just above a canopy of Fucus gardneri when exposed during two low tides in winter. Data were taken using a Viasala ruggedized probe and logger.

figure 3	figure 4

Fig. 5 BELOW. The loss of water from Fucus gardneri during wintertime low tides at Friday Harbor Laboratories, WA, was minimal during winter.

figure 5

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