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Sunday, July 23, 2017

Hometown hydromedusa

Last week, Eric's summer students were sorting through some plankton samples collected in Bodega Bay and Bodega Harbor.  Rachel spotted something different and took a closer look.  We're glad she did, because it turned out to be an interesting hydromedusa:


Meet Hydrocoryne bodegensis!  The scientists who first described this species (John Rees, Cadet Hand, and Claudia Mills) named it after Bodega Bay because they collected colonies from one of the Bodega Harbor jetties.  It's always fun to become familiar with local species that have "bodega" in their names!

This hydroid also has a polyp stage that grows attached to the substrate.  The tiny medusae (their bells are only ~1 mm high) develop among the clubbed tentacles of the polyp and then eventually break away to swim in the water column:

Modified from Rees, J.T., C. Hand, and C. Mills.  1976.  The life cycle of Hydrocoryne bodegensis, new species (Coelenterata, Hydrozoa) from California, and a comparison with Hydrocoryne miurensis from Japan.  Wasmann Journal of Biology 34: 108-118.


Although I didn't know it at the time, five years ago I photographed what might be this species, with a medusa just about to swim away:



Eric captured a short video of the Hydrocoryne bodegensis medusa, so I'm including a video file below.  While watching, note the following:

- 4 long tentacles, with visible (knobby) clusters of nematocysts
 
- each tentacle ends in a prominent rounded cluster of nematocysts (you can locate the end of each tentacle by looking for these rounded tips) 

 - a red ocelli (eye spot) at the base of each tentacle

- dramatic extension and contraction of the tentacles (this is likely a feeding strategy, e.g., increasing surface area to increase likelihood of prey capture)



 And one last view of this beautiful medusa with its tentacles extended:


P.S.  Thanks, Rachel, for spotting a seldom-seen hometown medusa!


Saturday, July 22, 2017

Golden sunset


Golden sunset, 22 July 2017
 

Thursday, July 20, 2017

Summer wind


It's been windy lately!  This photo was taken yesterday, 20 July 2017, but it could just as easily be a picture from the spring.

North northwest winds were blowing at ~20 mph (~17 knots) in the afternoon.

Water temperatures have been cool recentlyin the 10-11°C range.  And they've generally been cooler than average during the last few months.  To track the trends, you can look at the Bodega Ocean Observing Node site (click on the tab of interest).

Wednesday, July 19, 2017

Furry


Furry Crab (Hapalogaster cavicauda) at Salt Point on 14 July 2017.

P.S.  For additional photos and information about this species, check out the post from 21 February 2017.
 

Tuesday, July 18, 2017

Lasagna noodles on the beach?

While doing a recent beach survey, I noticed this Feather Boa Kelp (Egregia menziesii) washed ashore:


It looked quite youngrelatively short overall length, with broad blades, and a small holdfast.


When I looked more closely, I was intrigued by the holdfast:  



Can you see that the holdfast is attached to a small pieced of wood?



It might be easier to see this from below:


I wondered about the history of this kelp.  Did it start growing on a piece of wood that was lodged in rocks somewhere and then part of the wood broke off and washed ashore?   Or is it possible the kelp started growing on a small piece of floating driftwood?  Have you noticed Feather Boa Kelp growing on wood before? 

P.S.  I laughed when I read the description of juvenile Feather Boa Kelp on the California Seaweeds eFlora website.  It says they look like lasagna noodles.  A fun description of those broad, ripply blades!

Monday, July 17, 2017

Game of threads

Next up in the spider web series!  Here are some highlights from the past week of trying to photograph the diversity of colors created by silk threads and morning sun.  Feel free to pick your favorite!




















   Maybe they will be inspiration for a knitting or weaving project?

Sunday, July 16, 2017

Offshore fog


Fog off Bodega Head, 12 July 2017