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Pescadero Basin [This is Steve
Haddock taking a turn to report on some of the things we have been
finding during the blue-water SCUBA dives.] Being far from shore has
certain advantages. On moonless nights, the stars reach all the way to the
horizon, and on windless days the ocean stretches out invitingly in all
directions. Windless days are critical for blue-water
diving, as we
can’t operate effectively if it is blowing more than 15 knots. Today is one
of the windy days, and I’m not yet sure how I feel about being unable to
dive. I always love jumping in and seeing what bewildering variety of
species is assembled, but this break forces me to rest up and perhaps
catch up with the interesting things we have been accumulating. We have
been very fortunate so far. We have been able to SCUBA dive on 9 of the
12 possible days, and each dive has been unique and surprising.
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Abundant siphonophores greeted us on our first dives. This was good news,
since several of us are interested in them, but they took our breath away
in more ways than one: their potent stings set our lips and hands on fire.
After suffering through this medley of electric shock+nettle+burning, Karen
and I decided to make face shields out of pieces of lycra. So now in
addition to breathing like Darth Vader, we look like him as well. Mock us
all you want, but we have been sting-free since then!
Some of the predator-prey
relationships we have seen are also quite unique. How else would we be
able to observe the struggle between a siphonophore and a polychaete
other than by joining them in their own environment? In the picture below, the
alciopid has been snared by an Athorybia,
and has released a defensive red ink cloud. In a cascade of parallels, we
have also found the alciopid parasitic on a lobate ctenophore, and there
is another lobate ctenophore
that releases nearly identical red ink clouds!
One of my favorite finds
on this trip is the ctenophore I call “picocydippid”. This amazing
creature is bright blue with purplish lips, swims frenetically, and
measures in at just over one millimeter long (yes millimeter), while its
tentacles stretch out for at least 40 times that length. Many of the
copepods we are seeing are bigger than this little guy! Because of its
morphology, I’m fairly sure it is an adult and a new species as well. I
caught one on our expedition to Hawaii, but it was rudely eaten by another
ctenophore in the same jar before I could examine it. This time I was able
to take photos and document it as best as I could aboard the ship. That I could take decent
pictures through our dissecting microscope is just one indication of how
great a working environment the R/V Western Flyer
provides! I’d like to thank the crew for giving us steadfast diving
support, with all the extra effort required in launching and tending the
boat. So far the Gulf has had plenty to offer. The hazy blue water, a mix of tropical and gulf waters, is indicative of the productivity of the northern area and the influence of the warm oceanic water from the south. There have been many fascinating sights, like marea roja (red tide) a dense and dark monoculture of dinoflagellates that was less than half a meter thick, medusae dividing by fission, and siphonophores with specialized sections along the length of their tails. We look forward to more discoveries as we continue our visits to the realm of the gelata. |