Mearns Rock 2007
What You See
In 2007, the boulder is completely "smothered" by a thick growth of adult Fucus (popweed) plants, so thick that it's difficult to identify other organisms that may be hiding among the foliage. When we looked closely, we saw lots of tiny (baby) mussels attached to the plants, and when we lifted the plants to see underneath, there were barnacles. Although it is difficult to see, these are large Fucus plants with lots of swollen reproductive blades. A thin band of the filamentous green algae remains along the lower edge of the rock. The beach face below the boulder has about a 50% cover of large Fucus plants and a white covering of barnacles. The eelgrass bed is difficult to see, but it doesn't appear to be very dense.
What’s Happening?
Conditions in 2007 are dramatically different than any previous year, since 1991. During that year, the boulder was also "smothered" with young Fucus plants. That was only two years after the oil spill! Now, 16 years later (and 18 years after the spill), we see a very similar situation. It appears that young plants colonized the boulder in 2005 and 2006 and then grew extremely rapidly to a reproductive stage.
Why would this rich growth happen now, especially since we haven’t seen anything like this for some 16 years? Perhaps the water temperature has changed to favor the rapid growth. Plants need nutrients, such as nitrogen. Perhaps nitrogen levels in this area in 2006 to 2007 were higher than average over the past 16 years. Or maybe it was a wet spring and the young plants were not exposed to dry conditions during low tides. We will have to explore these ideas.
Will the abundance of life on the Rock ever stop changing? How long should we keep looking at it? What do you think the growth will look like in the summer of 2008, 19 years after the oil spill? We will let you know!
(07.01.07, Snug Harbor, Knight Island, Alaska)
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