Local patches

  

Recently, several people have asked me about the kelp beds that are visible just offshore of Bodega Head right now.  The calm ocean conditions and gray overcast days during the second half of July have helped make these Bull Kelp (Nereocystis luetkeana) patches stand out.

Most people in this area have heard about the significant declines of kelp beds throughout Sonoma and Mendocino counties during the last five years or so.  However, the kelp beds off Bodega Head are a bit of a puzzle.  These local patches of kelp have increased in number and extent during the last ten years, and that has become especially apparent during the last five years.

For the record, I started taking photos of some of the local Bull Kelp patches back in 2008.  As an example, here's one from 2016.  [Look for the darker blue/brown area in the water just beyond the shoreline.]

 

I'm not sure why the kelp beds off Bodega Head have increased while those at many other sites have decreased.  I have wondered if there might be some connection to more rock being exposed on the bottom (where kelp can take hold) if sand shifts during significant wave events (e.g., during the 2015-2016 El Niño).  But there are lots of other factors that could influence the success of the kelp here, e.g., water temperatures, nutrients, dispersal of spores, grazers, etc.  The reasons might remain a mystery, but the expansion of the local Nereocystis patches has been interesting to watch and raises many questions.