Mearns Rock Time Series
How does marine life recover from a major, one-time stress, such as an oil spill? As you will learn here, the answer is not simple.
Visit our Mearns Rock Time Series photo gallery to view a series of photographs of "Mearns Rock," a large boulder (approximately 4 feet [1.2 meters] high by 7 feet [2.1 meters] long) located in the intertidal zone at Snug Harbor on Knight Island, Prince William Sound, Alaska. The boulder is located on a very protected, south-facing rocky shoreline that was oiled during the Exxon Valdez spill in March, 1989.
This section of shoreline was not cleaned after the spill. We presume that the boulder, like the rest of this shoreline, was coated by spilled oil, which was gradually removed from it by natural processes during the first year after the oil spill. (Note that we have not yet provided photos of a "control" site, a boulder on a similar shoreline that was not oiled.)
NOAA biologists have photographed this boulder--and the animals and plants growing on it--once each year (in late June or early July) during the past 20 years.
Ideas to Consider
- How long should we continue to take photos of this boulder?
- You may want to create a photo time series of your own. Each year, photograph a boulder at low tide. Then, compare the photos to see how the boulder's marine life changes over time.
- For a class project, teachers may want to print (on a color printer) the large images of Mearns Rock. Then, cut out the images and ask your students to put them in chronological order. How closely matched are the students' results with the actual chronological order of the photos?
- Try our Graphing Project. Using photos of Mearns Rock, you'll graph the changes over time in the percent cover of rockweed, mussels, and barnacles on this boulder.