The talk is open to the public for anyone in Seattle who is interested.

—Jim Dodge

***

The American Fisheries Society annual meeting starts in Seattle in a couple of days. I will be in attendance, and am bracing myself for an onslaught of these stories. I worry that “I once saw an echo with a target strength of almost -12 dB re. 1 μPa at 1 m!” is not actually that impressive to most people. I suppose I will just have to fall back on my natural modesty.

It is time to reset the clock from the rise and fall of the tide, to the come and go of the school bus. Pack your bag and put in a few treasures…A little bit sad about the place you are leaving, a little bit glad about the place you are going. It is a time of quiet wonder – for wondering, for instance: Where do hummingbirds go in a hurricane?

I can’t say that question has ever kept me up at night, but I have wondered about it from time to time. Well, it seems that the question now has an answer. See the photo below, taken by Chuck at his parents’ house in Greenville, NC, during the storm:

Just chillin' at the feeder during the hurricane. No biggie.

Apparently, hummingbirds go wherever the hell they want during a Hurricane.

Winter in Hell from Enrique Pacheco on Vimeo.

Shot by Enrique Pacheco, and brought to my attention by Julia Whitty. Iceland is one of the strangest and most awesome places I’ve been, and getting to travel there this spring for a conference was an amazing privilege. This video almost makes me wish I had been there during the Eyafjallajökull eruption last year. From the photographer’s description on Vimeo:

This is a 8 minutes short film, not a quick youtube video, please be patient or watch it later.

I shot this film over the course of a year. It then took me few months to edit and color grade it.
…
Winter 2010, the stunning landscape of Iceland succumbs to the Arctic cold. Beaches and lakes get frozen, but something unexpected is going to happen… the earth shakes, warms up, and suddenly a big crack opens up at the top of the glacier Eyjafjallajokull. Lava, smoke, ash and fire come up from the depth of the earth, melting everything in its path.

The original is from here. Maybe now you understand why posting has been slow. At least I’m almost at the last line by now…

H/T to my friend Arielle for sending this.

Barham’s thesis is part of the early literature on the “deep scattering layer,” or DSL. This was a phenomenon that began receiving attention with the wide adoption of sonar during World War II. Ships with acoustic depth sounders would often see what appeared to be a second ocean bottom much shallower than the one they were expecting. Even stranger, this “false bottom” suddenly rose to the surface every night, frightening more than one captain by making him think he was running up on an uncharted shoal. It would descend again in the morning. The deep (sound) scattering layer, or layers, was present most places in the ocean, somewhere between 200 and 800 meters below the surface. After the war, some scientists began to investigate it in earnest.

One of the citations in Barham’s thesis is a paper by Gordon Tucker, from 1951. I recognized the name Tucker, because it is the name of a type of net widely used for sampling zooplankton. In fact, I spent a week my senior year of college struggling with a sticky release mechanism on one of these nets aboard the NOAA Ship McArthur II in the Gulf of the Farallones, offshore of San Francisco. On a whim last week, I decided to go up to the UW’s main library on campus to find this paper, which of course is not available electronically yet.

Back in my office with a pleasantly musty hard-bound copy of volume 10 of the Journal of Marine Research, I discovered that Tucker (1951) was the paper where he invented the Tucker net. What’s more, he did it to try to figure out what what was causing the deep scattering layer. His answer, based on cruises in the Bering Sea and near San Diego? Mostly myctophids, or lanternfish: little bioluminescent guys an inch or two long, with some krill in the upper layers as well.

In the same volume, I stumbled across, completely by chance, another paper on the composition of the deep scattering layer, this one by a Norman Marshall. Independently from Tucker, who published in the subsequent issue, he had argued for the same biological cause of the DSL—lanternfish—based on their theoretical sound-scattering properties, known widespread distribution, and daily vertical migrations. It was really cool, reading these old papers, to see the evidence for the “biological hypothesis” coming together into what would become our present-day understanding of the DSL.

But there was still more. On the back cover of each issue, the editors of the journal were listed. I did a double take. One was C-G. Rossby—yes, that Rossby. Another was Harald Sverdrup. If you haven’t heard of him, he was no big deal. Just has a unit of measurement named after him. And there was Thomas G. Thompson. He was the sort of guy who you might choose if you were trying to pick a namesake for a 274-foot research vessel, and wanted to name it after the father of American chemical oceanography. These guys were all giants, and it’s kind of funny to think of them scrounging for reviewers and hassling authors for revisions.

What was I talking about? Oh, right. PDFs. My walk up to the library to look for an old reference turned into a field trip to the Cambrian Explosion of modern oceanography. Thinking about it, this experience wasn’t totally unique—these kinds of bang-bang-bang connections often happen when I spend time flipping through hard copies of journals. I find interesting and useful things I didn’t expect to. For whatever subtle design reasons, the electronic paper-reading experience doesn’t yet do that. If you know a librarian, let them know.

Even better, if you know a California legislator, let them know. Cuts to that state’s higher education funding may force the largest oceanography library in the world to close. There’s old stuff at the Scripps Library that cannot be found anywhere else. If it’s moved to an offsite storage warehouse, it probably won’t be found anymore, period. The UW has already lost its Fisheries and Oceanography Library to cuts by a state legislature ambivalent to higher education. Don’t let it happen at Scripps.

A crab, seen from below, infested with a rhizocephalan. The crab's right side is drawn transparent to show the branching body of the parasite. Image from 'Invertebrates,' by Brusca and Brusca.

And you will spend the next half hour with your mouth open, descending through increasing degrees of stupefied horror, as you learn exactly what you are looking at. Congratulations. You just discovered the rhizocephala: the parasitic “root headed” barnacles.

The rhizocephala are a superorder within the subclass Thecostraca, the group of crustaceans that includes all the barnacles, but their form is highly modified from the familiar acorn and gooseneck barnacles. The only visual indication we have that these creatures are related to the other barnacles is their nauplius and cyprid larvae. In the normal barnacles, these larvae find a rock, stick themselves to it, grow a shell, and spend the rest of their days filter feeding.

Rhizocephalan larvae do not settle on rocks. Instead, the females settle on other crustaceans–usually crabs, and usually on the gills, where the crab’s exoskeleton is thinnest. This is important, because soon after settling, the larva injects its soft innards into the crab. This may take place through one of the larva’s antennae, wielded like a hypodermic needle, or the larva may molt and stick itself on the crab while it develops a special stylet inside its body. When the time is right, it everts this poker into the crab and injects its guts as a worm-like body called a vermigon.

This is where it starts to get really awful. The injected mass of visceral cells, now called the “interna,” starts to grow inside the host’s fluid-filled cavities, branching out root-like through the entire body, but concentrating on the digestive tract. Somehow, the parasite keeps the host’s immune system from attacking this network of invasive threads while it grows, drawing nourishment continuously from the host’s precious bodily fluids.

Rhizocephalon externa: it is the gross-looking yellow blob highlighted under the crab's tail.

When mature, the female interna extrudes an appendage out of the host’s body. This is called the externa, and it is little more than a gently-pulsing sac of gonads, attached to the host’s body by a short stalk, emitting a trail of pheremones to attract male larvae. When these larvae arrive, they land on the externa, and inject their soft insides into it. They then migrate into special seminal receptacles and fuse with the female, becoming nothing more than soft clumps of sperm-producing tissue, themselves parasitic on the already-parasitic female. Eggs are fertilized and released, and the cycle begins again.

But wait–it gets even sicker. In many cases, the externa is extruded under the crab’s tail flap, where it would carry its own eggs. Some species of rhizocephalans actually chemically castrate the crab, and then modify its behavior–that is, perform mind control–compelling it to take care of the parasite’s gonads as if they were the crab’s own children. This works even in males, who don’t ever carry eggs, and never exhibit any of these behaviors on their own. In these cases, the crab stops growing, and never molts again. It spends the rest of its days as a kind of zombie, eating food that will be sucked out of its digestive tract by the parasite that destroyed and replaced its reproductive system.

Now aren’t you glad you know all that?

Walker, G. (2001). Introduction to the Rhizocephala (Crustacea: Cirripedia) Journal of Morphology, 249 (1), 1-8 DOI: 10.1002/jmor.1038

This evening, I went with a couple of friends to watch the fireworks display over the lake from a small park by the lakeshore. The entire lake was crowded with boats, most of which had been anchored there for the better part of the day to get a prime spot for watching the show. The explosions themselves were fantastic, but almost as cool was the sight we saw afterwards: hundreds of boats, all filing out of Lake Union into Portage Bay, on their way through the Montlake Cut to docks and marinas in Lake Washington. It looked almost like some crazy firefly migration, and the video I took of it almost kind of does it justice…

Anyway, as the straggling boats from Lake Union continue to stream by the end of the dock, and various independent-minded Seattleites continue to set off various kinds of ordnance…happy birthday, America, and happy 4th to everyone in it.