An Ecosystem in Transition
The graph below shows
changes in the area covered by one of the
most abundant alga on the shorelines of
Prince William Sound, Fucus gardneri,
commonly called "rockweed" or "popweed." Because
this alga favors the middle part of the intertidal
zone where much of the heavy oiling
and cleanup occurred, its abundance declined
in many areas of the Sound. Beginning in
1990, scientists saw the cover of
rockweed increase steadily at oiled sitesuntil
1994, that is. From 1994 through 1995,
there appeared to be a noticeable decline
in cover, especially at sites that had
caused the decline in 1994 and 1995?
Scientists don't know for certain. Here are some possibilities:
Mean Abundance per 0.25 Sq Meter Quadrat by Year
do these trends over time mean for
recovery in Prince William Sound?
Scientists think they suggest that highs and lows in abundance of plants and animals will continue as the system adjusts itself. With time, natural controls will dampen the fluctuations in abundance of marine life. Most of these adjustments will not be noticeable, and to the casual observer, conditions will continue to look much as expected in an area that remains a very beautiful place to visit. However, these subtle changes may have implications for how scientists view the process of recovery from the one-time stress of an oil spill. Eventually, the changes also may affect other parts of the ecosystem that are commercially and aesthetically important, such as the fisheries and tourist destinations. NOAA scientists will continue to study the sound until 2005 in an effort to answer these questions.