Did you know that Monday, June 8th is World Oceans Day? If not, well, you've got all weekend to decide how to celebrate. I'm starting a two-month plankton-sorting project, but feel free to think smaller.

The Monterey Bay Aquarium, that colossal advocate of all things Ocean, celebrated with a webcast from Julie Packard, the Aquarium's founder and director, and Alton Brown, food geek extraordinaire. The picture of the two of them in front of the sardines (or maybe anchovies) is simply delightful. Julie Packard looks comfortable, professional, like the conservation matriarch she is. Alton Brown just looks crazy. His hair is disorganized, his glasses are thick, his smile is a goofy grin. He's ready to explode stuff, or at the very least set something on fire.

The webcast started with an introduction of our two hosts, sitting there with the sardovies (anchines?). I hate to say so, but it went downhill from there. If you want to experience it for yourself, once they post it online, I'm not saying you shouldn't. Just minimize your browser and look at something else while you listen to the audio.

After the initial video clip, the rest of the webcast is simply a series of photographs, without so much as a single Ken Burns effect. Sometimes the photos match the audio, as when a picture of a little kid accompanies Alton mentioning that he was raised on a steady diet of Jaques Cousteau specials. Other times they are almost comically mismatched, as when the aquaculture discussion is illustrated by a fishing boat hauling up a net. (A couple of powerpoint slides even make an appearance, but that's just so embarassing I'm not going to talk about it.)

I guess they were trying to keep bandwidth down, but in that case, why not forgo video altogether? My hopes were too high. I wanted explosions! Or at least fire!

Our IT guy streamed the webcast in the main lecture hall. About a half dozen of us showed up to start watching, and only three of us stuck it out for forty minutes, at which point we gave up and turned it off altogether. To be fair, it wasn't entirely the disappointing content. Warm sunny days are rare enough here in Monterey that they must either be spent a) playing hooky or b) working hard, oh yes working so hard, because you are so dedicated to science that you will not take even the sunniest and warmest of days off. Good little scientist!

Not-working and staying inside, for example watching a webcast, is inexcusable (blogging, of course, is an exception). So we quit, and yes, that means I am committing the sin of criticizing something that I didn't even finish viewing. Sorry! If anyone sat through the whole thing and wants to tell me what I missed in the last twenty minutes, I'd love to hear it!

Anyway, the most interesting topic from the first forty minutes was sardines. Actually interesting, I mean, I'm not being facetious. Here's a fun fact about Alton Brown: he adores sardines. He says he eats them, fresh or canned, at least five times a week. FIVE TIMES A WEEK. I don't even eat ice cream that frequently!

Sardines came up because sardines always come up when people talk about eating lower on the food chain, which in turn always comes up when people talk about sustainable seafood. It's an argument most famously presented by Taras Grescoe in Bottomfeeder: although is it certainly possible to overfish low-food-chain items, they are at much less risk than high-food-chain items, because there are more of them to begin with and their turnover time is quicker.

It's intriguing to note that all of our big terrestrial meats are bottom-feeders (grazers) with the notable exception of pig*. There are probably a lot of historical and ecological factors behind that, but I'll just mention one: on land, grazers outgrow their predators. Elephants are bigger than tigers. Bison are larger than wolves. But in the water, animals get larger and larger as you travel up the food chain. Tuna are bigger than sardines. Sharks are larger than shrimp. And whales are . . . complicated.** Given that a bison's got more meat than a wolf and a tuna's got more meat than a shrimp, it's pretty straightforward to understand why we eat at different trophic levels in different ecosystems.

Anyway, the point is that it would be more sustainable to gobble sardines the way Alton does than to scarf down salmon and tuna the way some people do. But most Americans don't want to. Why not? Alton suggests that the turn-off is that fact that you buy sardines with the head still attached: "Americans probably wouldn't even eat chicken if it came with a head. . . . we are a country of the cut, not the carcass."

(I bet he's been working on that one for a while. It's poetical!)

I'm reminded me of a curious ethical quandary that my husband and I banter over, sometimes more and sometimes less seriously: I'll kill it but I won't eat it, and he'll eat it but he won't kill it.

I've killed plenty of squid and fish for science, but I've never deliberately eaten any animal. My spouse, meanwhile, has never been a vegetarian, but readily admits he's too soft-hearted to kill anything larger than an ant in cold blood.

Who's the greater hypocrite?
Who's to judge?

Just to be clear, I'm not unconflicted about the scientific carnage I've perpetrated. I've tried to justify every animal death in terms of advances in knowledge contributing to conservation, but it still bothers me. A lot. In fact, it is a contributing factor to my not wanting a career as a research biologist. I suppose I could study plants, like my wonderful vegan friend who works on orchids, but they're not my passion. If I'm a biologist, I'm going to study cephalopods, because that's what I love.

That's what I kill.



* Pigs and humans have a lot in common.

** Many whales are big predators, like sperm whales. So they fit right in. But the very biggest, the blue whales, have to mess up my rule-of-thumb by being bottom-feeders (metaphorically speaking--they don't actually eat off the bottom, like gray whales)

I've sat through (heck, even instigated!) plenty of lengthy discussion about various definitions of life. But just now, I'd like to propose a brand new definition: life is anything that pollutes the environment. What do you think?

At first, it always seems like a good idea. Photosynthesis, for example. Here we are, just some simple cells swimming in water, bathed in sunlight, with plenty of carbon (mostly thanks to the volcanos*). Let's take those raw ingredients and make sugar! Incidentally, we'll produce a little oxygen on the side. Shouldn't be a big problem. Right? Wrong! It turns out that a little oxygen becomes a lot of oxygen, and oxygen is hugely reactive. Right off the bat it started oxidizing iron.

Once, iron was dissolved abundantly in the oceans, and the carefree phytoplankton probably never gave a second thought to the fact that they needed (a miniscule amount of) iron to build their photosynthetic machinery. But these days, almost all of the iron in the world has been transformed into iron oxide, rendering it virtually insoluble and therefore inaccessible to the very phytoplankton that need it. They must instead rely on oceanic fertilization by rivers and blowing sand from the Sahara. Bits of the ocean that don't have much riverine input and aren't downwind of any deserts are notoriously iron-poor. The low chlorophyll (indicative of low phytoplankton activity) in these areas was a big puzzle to oceanographers until they figured out the iron connection!

Jumping from single-celled goo to the mammals, let's consider gray whales. Our penchant for categorization compels us to divide whales in two broad ecological categories: toothed whales (think killer & sperm**) that eat seals and squid and maybe the occasional whaler, and baleen whales (think blue and humpback) that swim gently through the sea like giant Brita filters, absorbing plankton. But there are more than two ways to feed yourself from the ocean, and gray whales have gotten creative.

Gray whales are baleen whales, but rather than swim placidly through the water, filtering as they go, they've decided to dig for their meals. They're bottom feeders, foraging through the silty seafloor for crustaceans and worms. Now, if you've ever gone diving, you know what happens if you kick your fins too close to a sandy, or worse yet, a silty bottom. Clouds of dust billow into the water, obscuring your vision and taking a frustratingly long time to settle down. Now, imagine a whale deliberately rooting around in the muck! Gray whales re-suspend huge amounts of sediment, filling the ocean with dirty plumes that are easily visible from aerial surveys.

Sloppy eaters are always attended by those willing to pick up the crumbs, and gray whale mud plumes provide superb "ephemeral foraging opportunities" for seabirds (fun citation!). Millions of birds feed regularly off of gray whale plumes, making these environmental disturbances easily comparable to a human landfill or elementary school (at least from a gull's perspective).

My point is that all living things, from whales to bacteria, alter the world around them to some extent. Put a plant in a jar and it will eventually use up all the carbon and starve. Put a rat in a separate jar, and it will breathe up all the oxygen and asphyxiate. But put them in the same jar, and they can coexist for a little while--long enough for the rat to starve to death, or maybe eat the plant and then asphyxiate. Hmm.

Okay, add more plants, some insects, and eventually you'll find a balance of consumption of production, death and spawning. You'll have created an ecosystem.

So that's the game of Life: it changes its environment, pollutes it, if you will, and then some other Life jumps on the pollution as a resource. Meanwhile, we humans are the Protean player, the ecological wild card. We're something special in the sheer variety of transformations we can accomplish. Physical, check (we build dams). Chemical, check (greenhouse gases and holes in the ozone!). Biological, check (I can't even decide which species to pick--dodos? moas?--but we can eat pretty much anything out of existence). In addition to making a wide variety of changes, we also make changes very fast. We're changing things faster than we can even learn about the way they were before we started changing them.

Which is really pretty spooky.



* Yeah, so obviously this definition of life renders the Earth itself a living being. Volcanos belch ash and gas into the atmosphere and alter the global climate. Does this put me on the same page as Gaia theorists? And then there's fire . . .

** Sperm whales are weird! And not just in name. They are most definitely endowed with teeth, not baleen, but a guy named Milinkovitch proposed in 1993 that they are actually more closely allied with the baleen whales. He did some genetics to back it up, other people did genetics to contradict him, and people are still arguing about it. This should be interesting even if you don't really give a fig about genetics, because it also lets people argue about echolocation, which is undeniably cool. Toothed whales (including sperm) echolocate. Baleen whales don't. If sperm whales are truly more closely related to baleen whales, then either (1) sperm & other toothed whales evolved echolocation independently, or else (2) the first whales evolved echolocation, and baleen whales lost it somewhere on their evolutionary trajectory. Everyone agrees that (1) is extremely unlikely. It seems there's some evidence that embryonic baleen whales may actually have a residual "melon" (à la bottlenose dolphins) early in development--which would support (2).

I'm not talking about the romantic sea cow, morphologically named, but the ubiquitious sea cow, ecologically named.

Shame on me for using such fancy words! I meant this: copepods are sometimes called the cows of the sea, not because they look anything at all like cows (they don't) but because of their somewhat bovine behavior. They are herbivores--grazers of phytoplankton--and they are very good at it. The fact that all of the carbon, photosynthetically fixed from carbon dioxide into useable sugars by tiny single-celled oceanic grass, is available to be transported on up the food chain to eventually build tuna and whales, is due in large part to the steady, efficient grazing of copepods.

But, as I said, they don't look anything like cows. They are small (millimeters) and crunchy (exoskeleton). The stereotypical copepod has long, sweeping antennae and one eye. A single eye. In the middle of its head.

For a long time that didn't seem too weird to me, any more than anything else in the routinely weird and wacky world of biology; it was just something to remember about copepods--like a rhinocerous having horns. But just recently, as I sat in class watching a professor draw a copepod on the board, I automatically corrected him when he drew two eyes--and it struck me, quite suddenly, that the cyclopsian nature of the copepod is totally and utterly bizarre.

Let's take a moment to talk about bilateral symmetry. It's another biological fact that we tend to take for granted--that if you drew a line down your middle, the left side would roughly match the right. It's by no means a rule of life--think of anemones and jellyfish, who display radial symmetry, or sea stars and urchins, who've taken it a step further to pentaradial symmetry.* But bilateral symmetry has been around for a pretty long time. The most primitive bilateral animals are the flatworms, and they have two eyes even though they don't have a coelom**.

So I started reading up on copepods, and I found out that the single eye of adult copepods is a "persistent" larval feature. Like most other aquatic crunchies (crustaceans), copepods have a larval stage called a nauplius. It looks rather simpler than the adult forms, and with successive molts it adds appendages and segments until it has the proper number to be considered a grown-up. The nauplius form is also simplified by having a single "median" eye--that is, an eye that is set nicely in the center of its head (like a cyclops) and not off to one side (like a pirate).

Most copepod nauplii simply retain this median eye as they mature into adult forms, but most other crustacean nauplii (and a few copepods) split their eye up into the two (or more) compound eyes of adults. At least, that's what we think happens, but this hypothesis has not received unanimous support, so I suppose some folks think that the adult eyes derive from some entirely separate tissue.

I haven't found any explicit evolutionary discussion of this phenomenon. I can only suppose, however, that the single eye of the nauplius is a derived character. That is, I expect that crustaceans evolved from a two-eyed ancestor, and as their larvae became more and more specialized, some developmental gene mutated and they ended up with only one eye.

I'd welcome any discussion, wild hypotheses, or research articles on the subject. Be warned, however, that searching for the words "copepod" and "eye" together yields a wealth of information about the very intimate relationships many copepods have with the eyes of other organisms. What I said about copepods as grazers is all very true, but the group has diversified incredibly, and they have also excelled at the parasitic lifestyle.



* Actually, echinoderms are weird when it comes to symmetry. Their larvae are actually bilaterally symmetrical, and it is only when they settle and turn into adults that they develop radial symmetry. Bilateral symmetry is partially preserved in the sea cucumbers, and it is actually one of the characters that makes echinoderms close cousins to chordates. Read more!

** A coelom is a body cavity, the hollow bit inside you that holds all your gooey organs; since they don't have a coelom, flatworms are just solid chunks of tissue. Being a solid chunk of tissue, they can't have circulatory systems or respiratory systems, and have to rely on diffusion to move gases and nutrients around their body. Relying on diffusion means you need a really large surface area to volume ratio, and it's this restriction that keeps flatworms flat. I used to be rather distainful of the flatworms for being acoelomate; after all, the flatworm representative we meet most commonly in the lab, Planaria, is kind of cute but doesn't have much to recommend it. But then I met the marine flatworms, some of whom are more spectacular than nudibranchs, and I opened my mind to acoel virtues.