Mystery of the “spurting” mussels

If you’ve read any of my posts, you should realize by now that clams are pretty weird. Some catch live prey. Some have algae in their bodies that they “farm” for food. Some can bore into hard rock. Some sail the seas on rafts of kelp. Clams live in a competitive world and have had hundreds of millions of years of time to evolve to try out all sorts of weird, unlikely ways of life.

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U. crassus in a Slovenian river (Alexander Mrkvicka)

The thick shelled river mussel (Unio crassus) is known from many rivers and streams of Central Europe. As this is a very well-studied region of the world, many generations of academics have noted an unusual, seemingly inexplicable behavior undertaken by these mussels at certain times of year.

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U. crassus propped up on its foot (UCforLife)

Using its muscular foot, U. crassus pulls itself to the edges of the streams and rivers it lives in until it is partially exposed to air. It orients itself at a right angle with the surface of the stream with its siphons (two little snorkels coming out of the shell) facing out towards the water. Like all bivalves, U. crassus can act as a bellows by opening and closing its shell to pull in and push out water through those siphons. It has one siphon above the water and one below, and it proceeds to suck in water and spray it into the center of the stream using the power of its suction. The water can travel over a meter away and they continue this spurting about once a minute, sometimes for hours.

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Squirting water into the stream! (Vicentini 2005)

Needless to say, this is a very strange and unlikely behavior to observe in a mussel. It is exposing itself to potential dessication or suffocation from exposure to air. It is vulnerable to predation from terrestrial mammals and birds. There has to be a very powerful benefit from this behavior to outweigh those risks. And why squirt water into the air?

Some researchers proposed that the mussels were traveling to shore to harvest from the more plentiful food particles deposited there. But why would they face their siphons away from the shore then? Other workers suggested that it was a way to reduce heat stress through evaporation, though that also seems unlikely, considering the water is warmest in the shallows. The question persisted for decades in the minds of curious malacologists.

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Top-down view of spurting behavior (Vicentini 2005)

In 2005, Heinrich Vicentini of the Swiss Bureau for Inland Fisheries and Freshwater Ecology decided to try settle the question of why these mussels spurt. He observed several dozen of the mussels crawl to the edge of the water and diligently begin squirting into the streams. In the name of science, he put himself in the path of these squirts, caught the water and used a hand lens to observe that the squirted water was full of mussel larvae (glochidia).

Lifecyle of U. crassus (Rita Larje via UCforLife)

U. crassus falls in the order Unionida, a group of freshwater mussels distinguished by a very unusual method of reproduction. They are parasites! Because they can’t swim well enough to colonize upstream against the current, they need to rely on fish to hitch a ride. Some have evolved elaborate lures to convince fish to take a bite, then allowing them to release their larvae, which attach to the fish’s gills like binder clips and ride all the way upstream. Once they have reached their destination, they detach and grow up into more conventional burrowing mussels. It’s a weird, creepy and wonderfully brilliant strategy that enabled the mussels to invade the inland rivers which would otherwise be inaccessible to them.

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Loach (type of freshwater fish) gills with unionid larvae attached (UCforLife)

The mussels appear to be spurting out not only water, but their babies. They gain a couple of advantages from this. For one, their larvae can distribute further than would be possible from the bottom of the creek. Instead, they are released at the center of the surface of the stream, where they can be carried for a much longer distance by the current before they settle at the bottom. In addition, the splash of water on the surface may mimic the behavior of insects and other fish food falling in the water. A curious minnow might venture to investigate the source of the splash, where it would promptly breathe in a cloud of larvae that get stuck on its gills. A pretty rude surprise, but a brilliant trick to give the baby mussels the best chance of surviving.

So again, clams prove themselves to be far more clever and interesting than they might initially seem. U. crassus and other members of the Unionida are an ancient and globally distributed lineage which have evolved all sorts of weird and wonderful ways to maintain their river lifestyle. Unfortunately, rivers are some of the most widely damaged environments in the world. A majority of freshwater mussel species worldwide including U. crassus are endangered by habitat loss, overharvesting and pollution. But more research into their unusual biology can help us understand ways we can enhance their conservation, with the hope of providing more habitat for them to recover populations in the future. New projects in Sweden and other countries aim to recover habitat for their larvae to settle along 300 km of rivers, and research the fish species which their larvae prefer to hitch a ride on. With more work, we can hopefully ensure that the streams of Europe will harbor little mini super-soakers for millennia to come.

People (and frogs!) before cows

It was hard not to feel irritated as I opened the homepage of East Meadow Action, a grassroots group recently formed to defeat the development of Student Housing West (SHW), particularly regarding the Family Student Housing project on East Campus. The group has its heart in the right place. They believe that the field at the base of campus is a setting deserving of preservation, and are trying to prevent the building of new student housing to achieve this goal. I’m writing this to counter a number of points brought up on their site about the planning and design of SHW. I feel qualified to discuss this matter because I’ve been serving as a graduate student rep on the planning committee for the project since its early days last summer. From the start, I’ve been dedicating my efforts to keeping the project economical to ensure lower rent and as dense as possible, to prevent campus from sprawling into land needed by wildlife. I’m sorry to say that East Meadow Action’s efforts to defeat construction will harm both students and the environment if they succeed.

Student Housing West is an enormous planned development on the West side of campus designed to house ~2600 undergraduates, 200-220 graduate students, nearly 140 apartments for student families and a childcare facility. Well, it was initially planned to be on the west side of campus, beginning below Kresge College and continuing down the hill to the current site of Family Student Housing. That was the site university administrators provided for developers pitching their concepts for the project in an extended series of meetings last summer. We selected one developer, Capstone Development Partners, because of their proven track record of student housing construction and management. I personally voted for them because their plan had the highest goals for sustainability and the team made it clear that they would work to adapt to any contingencies which would surely arise during the future planning process.

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The red-legged frog. Apparently Californians ate them to near-extinction, no joke. From Wikipedia.

It turned out that their promised adaptability was put to the test when we were informed that nearly half the site would not be usable for construction. It turns out that a very cute and endangered species, the Red-Legged Frog, uses that corridor for their annual migration from the northerly forests to the grasslands near the Arboretum. Capstone suddenly had to work with half the space that they had initially anticipated for the 2800 students destined to live at West Campus. In addition, it meant there would be no housing prepared for current families living in Family Student Housing (FSH) when it was torn down to make room for the new development.

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Aerial view of the two sites. Source: UCSC CHES

This news could well have killed the project. SHW would not be built in time. Students would be left to fend for themselves and find housing in town on Craigslist. But members of the planning committee discussed another site for the new FSH, one which I have long personally considered a waste of space: the “meadow” near Hagar and Coolidge Drive. As an environmentalist and earth scientist, I bristle at the suggestion that the field at the base of campus is some kind of natural grassland. This space is heavily damaged; if it was left alone, it would return in a few decades to being redwood forest much like North Campus. But it hasn’t been left alone. It is instead a haven for domestic cows which graze and trample the space year-round. The animals, while endearing, continuously roam mowing every blade of grass to a stub, happily emitting methane on a prime piece of real estate.

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The cows declined to comment on their thoughts re: Family Student Housing.

Perhaps the current ongoing environmental review of the site will find that the land is needed by some sensitive species other than domestic cattle. If that turns out to be the case, then I will shut up and the project will probably need to restart at the drawing board. But some of the “alternative sites” that East Meadow Action assures us are available on campus (but never get specific about) seem far worse to me. Some possibilities include the forested land north of campus or the trailer park on the Northwest of campus. Both of these places seem much worse candidates to pave over to me in terms of ecological value (redwood and oak woodland) or their need for people (the trailer park is some of the most affordable housing on campus and much beloved by the students living there). I would much rather pave over cow pasture than a forest or someone’s home.

When I read through the website of East Meadow Action, I am struck that the centerpiece of their argument is the aesthetic value of lower campus as open space. I confess that I find this extremely irritating. It’s irritating to me because aside from being an advocate for conservation of sensitive species like the red-legged frog, I am also a student who has to get by living in this town, and I don’t have the luxury of worrying about aesthetics. When they mentioned Ranch View Terrace as an example of “building done responsibly”, my opinion was sealed. Take one look at the floor plans described for the single family homes of Ranch View Terrace, “a large housing complex set back from the road and mitigated by vegetation and topography.” How exactly are we going to house 2500 students in single family homes, artfully hidden behind trees? East Meadow Action is not motivated by environmentalism. They’re motivated by the same Not In My BackYard mentality that is choking the development of dense housing in town. We are in a housing crisis and their ocean views are a luxury that we can’t afford.

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East Meadow Action’s ideal for student housing.

I agreed to be SHW rep because I want to make sure future graduate students will have an affordable housing option on campus. I currently am “lucky” to spend 40% of my stipend on rent in town. When I first came to attend grad school here I had to deal with Craigslist and ended up paying over 60% of my income for the first two years I lived here. Students are pursuing extreme solutions. I know people considering living in the woods, or in unzoned bedrooms in town that are another source of tension with the community. It will only continue to get worse as rents rise in the coming years.

Right now, all we can do to remedy the issue in Santa Cruz is pass rent control ordinances and increase supply. SHW is the best project we have to increase supply and do so ensuring maximum density. I want UCSC to continue to be a forest campus, which necessitates not chopping down trees. I am trying to ensure that students have an affordable housing option on campus. I want student families to have guaranteed housing that comes online right when their previous outdated complex is torn down. The sentimental affection that some may feel for the aesthetics of a cow pasture strikes me as the privilege of a comfortable and vocal minority. I value the croaking of frogs and the laughter of children over the yammering of NIMBYs and, yes, even the mooing of cows.

Dan Killam

Fourth Year PhD Candidate, UCSC Earth and Planetary Sciences

University of Southern California ’12, BS Environmental Studies

Graduate Representative for Student Housing West

No Man’s Sky: An Environmentalist’s Review

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Approaching a beautiful lake-filled green planet, which unfortunately turned out to be covered with hostile robots.

I’m entering the atmosphere of this planet in full knowledge that I don’t have the fuel to lift off again. Normally, this wouldn’t be an issue, but the weather strongly tends towards acid rain and the average temperature is well above 150°F. So when I’m landed, I’m going to have to be quick about harvesting some plutonium (an odd choice for fuel considering its rarity on Earth) to use for my ship’s launch thrusters. When I get out to do so, my life support systems immediately begin using power and I realize my harvesting tool is low on juice as well. I could easily die here, alone and hundreds of light years from the nearest real-life human.

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My home base, on a frozen lake on the tundra planet I call home. One of the strange hog-faced, antlered bipedal herbivores is in the foreground.

The main enemy in No Man’s Sky is scarcity. Everything from your space-suit’s life support systems to the hyperdrive you use to travel between planets requires some amount of resources to power and repair. Most planets are not friendly in conditions. They can be frozen to -200 degrees, or +200 or both in a day. Windstorms and acid rain can sap away at your suit’s life support systems. You are truly subservient to the environment in No Man’s Sky.

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Weird hopping pineapple creature in the foreground in this strange fungus-dominated toxic world, where acid rain quickly sapped my suit’s life support systems.

There is a stunning variety of animal and plant life present in the game. All environments and the inhabitants thereof are generated by an algorithm, meaning that the game’s creators can’t be fully aware of all the billions of worlds existing in their fictional galaxy. I have seen flying worms, giant predatory dinosaur-like creatures that chase me on sight, and what can only be described as a hopping pineapple. Each planet is its own ecosystem. Most creatures are uninterested or fearful of you, though a few do seem to chase me or attack in defense. Some attack each other.

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A creature reminding me of a terror bird on a burning hot desert planet.

To be fair, the ecosystems are somewhat limited. I have yet to see truly giant trees rivaling the redwoods of my own real-life planet. I haven’t seen icebergs or glaciers, because each planet only has one real biome. There are no ice-caps or climate differences on each world, which is disappointing, but typical in science fiction (think Hoth or Tatooine from Star Wars). I haven’t seen a running river, which would likely be too computationally expensive to generate. All oceans and lakes seem to be static at a certain sea level. There are no differences in gravity between worlds, most likely to simplify gameplay. Star systems have planets and moons are not to realistic scale, with planets and moons far closer than they should be, probably for visual effect.

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Triceratops-like creature and a weird tubby feathered animal, with a crashed freighter in the background.

Some of the design limitations are interesting from an environmental perspective. There are orbiting space stations, but no cities to speak of. The sparse planetary settlements have at most a few inhabitants in a few buildings. Did the civilization of this fictional galaxy suffer some calamity which decimated its population? Or did they make a conscious decision to spread out and dismantle their cities in subservience to environmental preservation? Perhaps No Man’s Sky is the most extreme manifestation of the Kuznets curve. As human societies mature and living situations improve, their policies begin to value conservation and public health instead of economic growth.

In this way, the civilization of No Man’s Sky has achieved a near-environmental utopia. The player’s actions, however are interesting in their persistence. When you destroy a plant or harvest resources, they do not return. The changes that you make are truly persistent, and the game does not fill back in the gaps. As I rode my buggy over the surface of my own planet, I felt a twinge of regret running over the strange coral-like creatures in the warm canyons between stretches of tundra, because they will not regenerate.

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Remnants of a disbanded city? This world was a frozen archipelago with a yellow sky.

No Man’s Sky has been heavily criticized by many players, who felt it didn’t live up to the hype it received before release. Several updates have been added to improve the core gameplay and story in the last year. Regardless of the improvements of the game itself, I find the concept and environmental ideas in the game to be engrossing. As a real-life naturalist, the experience of exploration and nature-watching in a game is also fun, with the added novelty of knowing that every creature I see has likely never been observed before.

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A modern settlement, in harmony with nature.