Rachel Merz:	I have several goals that I want to do with this lecture thing. I want to do them simultaneously. One is that the thing that I most love about hearing faculty lectures is to have that sense of what the insider's view is. How is it that an art historian looks at a piece of art? What do they see? How does someone translate between one language and another if they're talking about poetry? How does an economist get their data? These are amazingly interesting things to me, and often the best part of any kind of faculty lecture is when you get that sort of insider's view. Part of what I'm doing here is spending some more time telling you how I do things and how the students who work with me do things so that we can have that view. 
	A second part of this is to talk about how I work with students in the field, how I work with them as younger colleagues, and how we develop projects together. The third thing is a thing I think I do with every lecture I ever give, which is to celebrate invertebrates, that I'm really interested in organisms that are different than we are and I'm interested in their interactions with the physical world. I think that the things that I'll be showing you today will hopefully illustrate that.
	To begin, where are we? This is Friday Harbor, Washington. This is an island on the San Juan Islands. It's about an hour north of Seattle, and it's where I often do projects. A good thing about an island is that it's a little bit difficult to get to, and so that means that there's a little bit less in the way of [inaudible 00:01:39] of this island. It's one of the reasons that the University of Washington has a marine lab there. If you were flying over it, you might see this strange collection of buildings. This is the Friday Harbor laboratories. What you see here right along the coast is a series of buildings. These are all labs, and in the summertime there is on the order of maybe 250 or so biologists that congregate there. Many of those are associated with classes, graduate classes as well as some undergraduate classes, but there are lots and lots of researchers who come here.
	If you were on the ground, this is what it would look like. Each of these labs has a different sort of character. There's an invertebrate lab, there are embryology labs, there's all kinds of things that are going on here. Now, what you can't quite see from this picture is that back in the woods here is where there are all kinds of places for people to live, so there are huts and there are cabins and there are duplexes and there are apartments and there are a whole array of places, including for those of you who are not biologists but who might imagine that you might want to go to this place, there's a thing called the Whiteley Center, where if you want to go write a paper or develop a proposal or paint, there are facilities for you to go there and do that too.
	Now, I'm going to show you, the next picture is not a modern picture. This is a picture, it comes from when I was in graduate school. This is some friends who were in a hut across the way, and this hut now no longer exists, it's been replaced, upgraded, but what is still there of course are the raccoons. When you are there, you are there totally in and amongst the wildlife that [inaudible 00:03:30]. The other thing that is true is that the community of scientists who are there have their own traditions and going there for me is like going to a homecoming. 
	One of the things that makes that true is that all these different kinds of housing that exist at the labs means that people bring their families, and so there are lots of kids who grow up in this setting and they get to know people at different stages. Another thing is that it's habit-forming, Friday Harbor is, that once you go, you want to go again. This for instance, this is a group of my friends and me in graduate school. More than half of us still go back there regularly. When you go there, there is this great community of scientists.
	There's some other traditions. Okay, so this is one of the main summer entertainments. This is the Invertebrate Ball. This is where all the scientists come and they dress up as things that they do or study. For instance here on the left there, there is Louis Druehl, who's a world famous kelp biologist. He's dressed up there as bull kelp. Then his partner there was my graduate advisor, that's Michael LaBarbera. He studies the interaction of organisms and flow, and so for this particular Invertebrate Ball, he was turbulent flow. His line was he used to be a random eddy, but now he's turbulent flow. This is [inaudible 00:05:05]. 
	Now, another part of the tradition is that the labbies take part in the Fourth of July parade in Friday Harbor. This was last year. There seemed to be sort of a cnidarian theme going on here. These are jellyfish, if you couldn't recognize them. This is a sea pen. Here they are though, marching down the street, having a great time. People who have been coming for decades participate in the parade, but also if you were just there as a student for a summer, you could do that [inaudible 00:05:35].
	Another part of the tradition there is the interaction with the citizens in citizen science kind of things. Several times during the summer, there's what are called organized beach walks. Basically, scientists, students from the labs set up camp at some site and townspeople and tourists and whatever come, and whoever's there playing the role of the scientist is explaining the world to them. This is Leah Lee and Mark Levine-Weinberg you might recognize Swarthmore students who were in the middle of this particular one.
	People come to Friday Harbor because of the labs, because of the communities there, but we also go there because they've got great tides. By this I mean in different places in the world, different amounts of the coast are exposed during low tide. In this part of the world, it's a good chunk of the coastline. The tides there are a little bit different than our East Coast tides. The top graph here marks what the normal East Coast tide is like, and that is that we have two highs and two lows a day and they're about equal size, but this is what the West Coast tides are more like, certainly in Puget Sound. That is that there is a high-high tide and a low-high tide and a low-low tide and a high-low tide. What this means is if you're going to be out working, you have to work in the intertidal in this lower low tide. That's going to come over a set number of hours in a given day and that's when you have to be there. There's really no choice about that. 
	Now, what's cool about these low tides here is that the water changes level pretty dramatically. This is a picture of the Friday Harbor docks, and the thing that you can keep track of is right there is ... This is a floating dock out here and that's a rampway out to the dock, and here's a little diver shack. This is high tide and this is low tide, so something like 20 feet of water disappeared and when it does, then the intertidal is exposed. In that intertidal are tons of wonderful, fabulous creatures that are just waiting for you to go and study them. 
	Now, the other thing to keep in mind in the way this works is that depending on the position of the sun and the moon, we have more or less extreme tides. When the moon and the sun are lined up, so that's full moon or new moon, we have what's called spring tides. They last typically for about a week and the tides are more extreme during that week. Then they're followed by neap tides, which also last for about a week, where the moon and the sun are kind of at right angles to each other and cancel their gravitational forces, and so the tides are not as extreme. 
	What this means in a practical sense is that when spring tides are going on, that means that's when we work. That's when the low tides are the most extreme, the most intertidal is exposed, and so you have about a week of pretty intense work where you have to be there when the tides are low. You actually need to work in the outgoing tide, so that would be on the order of ... You look up the tide in a tide table and it seems very reasonable, say it's 8:00 in the morning. That's not bad, except that you're going to work in an outgoing tide and you got to get ready so that means you're getting up and out at like 5:00. You do that for a week and you're kind of exhausted and then you have a week where you're analyzing your data and recovering from that and [inaudible 00:09:14] beginning. 
	Now, one last thing that's really good about Friday Harbor is that those low-low tides in the summer happen in the daylight. In the winter, they happen at night. I don't think Friday Harbor would be a marine lab if that weren't true because as cozy as that looks, I have to tell you being out in the nighttime is not that much fun, not the second and third and fourth and tenth nights. 
	Now, the way I work with students is that we start at the beginning of the spring tide series. I take them on every day of the spring tide to a different habitat. We have sort of an ongoing conversation about that habitat every day. What are the organisms that live there? What are the things that catch their eye? What are the patterns? Where do their curiosities lead them? Then at the end of that day, we go back to the lab and I pose a question. If you had to work in this habitat, what would you want to be doing? What is the question that's most interesting for you? And so after a week of this, we have a pile of questions and then we have a neap tide week to try to figure out which of those is the most interesting and most doable questions. Hopefully by the end of the neap tide we have maybe one or two questions that seem like the ones that are most likely, and so we begin on them.
	In the past few years, a lot of students who've worked with me have worked at False Bay. If you were on the shore and you were looking at this, you would say, "Oh, this is a great place. I can just bring my boat in here, there's a lot of water, everything's going to be fine," but six hours later, this is what it looks like. If you are a marine biologist, you are really happy about this state of things. This is a great bay. You have an extensive intertidal to work in. To give you a little bit of a sense of that, here's this bay. It's about a kilometer long, about a kilometer wide. It's 300 acres, and the campus here is about 450, so you can get a sense. It's a pretty big space.
	It's a preserve, so the University of Washington has protected it. At the northern end of it is where False Bay Creek comes into it, so that's the part of the bay that is influenced by fresh water. It's also the one that gets exposed the most, and so it's going to be warmer in the summer and cooler in the winter. At the mouth, there is a pretty extensive eelgrass bed, and then this drops off quite deeply here, and so this is the area where there's likely to be the most currents. 
	Now, to give you a sense of what is draining into this bay, here's an aerial view of False Bay Creek, the sort of agricultural land that is around it. It is draining this valley. There's not that much that is industrial there, but there is some agricultural work, including these guys. There's a certain amount of terrestrial runoff that is happening, and so as we enter the bay from this side, the question would be what do you wear? This is what you wear. You don't know what the temperature will be like. It could be rainy or misty or whatever, but you're pretty sure you're going to get wet, and so you're going to be happy what you're going to wear is waders. I have a lot of waders, so if any of you guys want to come visit, I can take you out.
	Then what we do is we get out on the bay and if you follow my instruction is you lie down on your belly, and the bay looks different. Instead of it looking like a big, empty thing, what you begin to realize is that the surface is all pockmarked with all kinds of things. Each one of those divots is the home of an animal. Some of them are bivalves, some of them are various kinds of arthropods. There are lots of worms out there. Each one of those organisms needs to be moving water to in and out of that sediment in order to be able to have oxygen. 
	What that means is if you dig up the sediment, what you'll see is that there are these tan areas that are traced as opposed to these darker areas, and they are the ones that clear water with oxygen is interactive. All these animals that live in the sediment are causing oxygenation to happen around these areas and are therefore controlling essentially the chemistry of the near shore. Actually not just the near shore, the bottom of the ocean is like this. There's all kind of organisms and they are pumping water and influencing the chemistry there.
	Now, the other thing is that in this sediment are sand grains, and those sand grains have a ton of little critters that are living around them, and so many, many of the organisms that live in this sediment are eating the sediment. They are like earthworms. They are taking bites of this mineral material that is not organic sand and then digesting it. You might come to a place like this in the bay where it has all these funny little squiggles and you wonder what these little squiggles are, and the squiggles are poop. 
	Here's a fecal mound being built by a worm. Now, the worm doesn't really care about the fecal mound. What the worm is doing is eating sediment down below and its body is like a conveyor belt and moving that sediment out on the top. These animals are not only moving oxygenated water in and out, they are moving sediment. The suggestion is that Puget Sound alone is probably turned over to a depth of about half a meter every five years by the process of these organisms. 
	The sediment then, it's a place to live, it has got food in it. It's also a protection. It's protection from extreme temperatures and from some predators, but I want you to realize that all of you who've probably enjoyed seafood ... I wouldn't say probably. All of you who've enjoyed seafood probably have some molecules in you that came from worms that lived in those mudflats. We have a much more direct connection to [inaudible 00:15:53]. 
	Now what I'm going to do is talk about a series of projects that different students have done. The first one I'm going to talk about, it's by Rachel Crane here, I'm going to give you the most detail about because I want you to see how it is we go about solving a series of problems. Then I'm going to give you some shorter vignettes of other kinds of critters.
	This is Rachel Crane and we're taking on the lugworm mystery. Lugworms are fabulous big, juicy worms. They are segmented worms and they live in burrows like this. In fact, lugworms are the ones that did that little poop pile on the top of the sediment. Now, the thing that's interesting about False Bay is that we have two species of lugworms. I don't know from your eyes, but from the eyes of people who aren't necessarily yet biologists, whether or not these two worms look alike, but to me they look a lot alike. That's its head over there, this is the head here. There's a whole series of gills on both of them, and then this is the tail and that's the tail. 
	They turn out they're about the same size, they live in the same way, they're really very closely related. We have them digging up the space in the bay in this way. In that slightly tan-looking area, there's Abarenicola pacifica lives, and then in the green area is Abarenicola claparedi. Hobson '67 described this. At that point, the explanation for how they were distributed here was the idea that Abarenicola pacifica, the one that lives near the False Bay Creek, was more tolerant of terrestrial conditions than it was more tolerant of being heated or being cooled or being exposed to freshwater. And then claparedi was a more oceanic species that was down here near the mouth.
	Now, that could be. There are lots of things that are [inaudible 00:17:53] because of those kind of reasons, but the tricky thing about this is if you go to different bays and different places, the position of these species is altered. In some cases, claparedi is high and Abarenicola pacifica is low. There's been this sort of standard question. What's going on with these species?
	We decided that one of the things that we noticed as we walked down in the bay was that the quality of the texture of the sediment changed, and that when you're at the north end of the bay where the water is coming in, the freshwater's coming in, it's relatively solid under your feet, but as you get farther and farther out, it becomes less so. We wanted to quantify how different is that sediment?
	Here's Rachel. She's doing a thing that she invented called the drop test. Now, what she has in her hand is a metal rod on which we can string weights, and she's going to drop that rod, it's going to stab into the sediment, she's going to pull it out. She's very cheerful in there, and we're then going to measure how far it penetrated the sediment. [inaudible 00:19:04]. She was totally lovely to work with. 
	All right, so here's some data that come from that kind of analysis. We wanted to test the kind of chemical properties of the sediment. Along this axis, I have how much the rod weighed, the mass, which is in terms of it being dropped, kind of equivalent to force. This is how deeply it stabbed into the sediment. Now, for a lot of you who are used to looking at graphs, so you're going to be unhappy that this graph is plotted the way it is, it feels like it's backwards, but what we're doing here is following the biomechanics tradition, which is following an engineering tradition, which is setting us up like a stress-strain curve. 
	This is a way material testing is often displayed, and so the idea here is that this sediment, the sediment that's associated with pacifica, which is the one near the land, is pretty stiff sediment. The penetration depth doesn't increase very much even though you're increasing the weight. On the other hand, in this one, the one that's out near claparedi, the sediment is a lot goopier. The rod penetrates the sediment greater and greater degrees the more mass you add.
	Now, these are gorgeous data. Look at this. This is just totally amazing that you could have two species, you could wander around and take these kinds of data, and that they would be as clean as this. This gave us some sense of security that what we were working on was in fact ... That the sediment could be important to them.
	Now, one of the questions we'd say is, "Okay, so what makes the sediment be like that? Why is it goopy in one place and not in another?" We think the key here is in what are the component parts. This is [inaudible 00:20:55] of sand, and what I'd like your eye to see is that this is like a zillion little mini ball bearings. They are rounded, they are relatively large. In contrast, clay is completely different in its shape and it's much, much smaller.
	When we take sediment samples from these two different habitats, we see a strikingly different picture. In the green bars here, these are A. claparedi, the ones that are out in the goopy sediment, and what you see is that the size of the sediment on this axis is dominated by what we would call sands. The sediment that you get where these goopy muds are are made mostly of these fine sands. In contrast, the sediment that comes from the claparedi is what we would call poorly sorted. It has a lot of different size classes within it and very importantly, it has this silt and clay component. 
	Now, the reason that that's important to the mechanics of this is that if you think about all these little ball bearings, they work well enough when they're by themselves, but if you have tiny little particles in with them, then they can't move as much. Here's a graphic [inaudible 00:22:17] used this week in Bio 2, but it was perfect for my purposes here. The idea here is that these are the clay particles and they get stuck between the bigger sand particles and they keep them from moving, and so that means that the sediment that has those clay particles in them is actually much firmer.
	We begin to have some information here about that A. pacifica lives in these sediments that are much stiffer and have higher clay component. They're not as well sorted. The claparedi live out here in stuff that is mostly sand. Okay, that tells us only so much. Why do these two worms that look like each other, that live the same kind of way, that are of the same size, why are they separate? We did a time-trusted biological phenomena, which is that we transplanted them. The way these transplants go is that we dig up some pacifica, and these worms have to be in perfect shape. They cannot be damaged by this process at all. We then put some of them on their own sediment and allow them to build burrows, and what you find is that on their own sediment, 100% of them make burrows and almost all of those burrows are vertical, which matters because this is the way they initially want to live.
	If we then take these guys from the stiff sediment and we take them out towards the mouth of the bay where it's soft, they do a pretty good job of burrowing and fewer of them, but still most of them, are in this vertical orientation. The story changes a little bit when we take the worms that are used to this soft sediment, and first we have them burrow in the soft sediment, they do a pretty good job. Most of them make vertical orientation, but when they're challenged by the stiff sediment of the high intertidal, they pretty much fail. We have about 65% completing their burrows, but most importantly, only 25% of those are vertical burrows. 
	It looks like part of the answer here is the claparedi simply can't burrow in the stiffer sediment. Still, what's the difference in their bodies? Why is this [inaudible 00:24:35]? We have some observations from the field, and one of these is about body stiffness and one is about slime. All right. Rachel Crane made this great observation, which is that the body stiffness of the worms, pacifica, the ones that are in the stiffer sediment, are they're like little hotdogs. They are little rigid worms, relatively speaking, and the claparedi were not so rigid. How do you test how stiff their bodies are? Well, we did this completely ridiculous and totally fun experiment.
	What you're looking at here is the barrel of a pipet that's pointed at a video camera. What I've done is taken a worm, this is a live worm, and I've balanced it on that little pipet, and I'm measuring how fast and to what degree it bends on its own. All right? And so here's a couple of different sizes, A. pacifica. We do this, we measure the angle, and there it is. Now if we take the wimpy worm, this is what happens. They really are wimpier. It turns out highly significantly they are wimpier, and so they really do have more wobbly bodies. Why? Why could that be? The answer is all about how much muscle they've got in their body wall.
	Here's some SEMs where I've done cross-sections of worms that are of sort of equivalent size, and what I'm interested in is this layer that is the muscles that are associated with the body wall, which is associated with how powerful they are in terms of being able to burrow. It turns out that A. pacifica, the ones that live in the stiffer sediment and that have a stiffer body is about 1.5 times as thick. We have here now finally a morphological difference between these worms that wouldn't have been apparent from the outside.
	Now, as to slime. The claparedi, the ones that are the wimpy ones, you do have the sense when you're handling them that they're putting out a lot of mucus. All right, really? [inaudible 00:26:44] how do you measure how much mucus something is putting out? Okay, well, we did it. What was the outcome of that is that in terms of the amount of mucus produced, that claparedi do, for any given body size, make about twice as much mucus at any given moment as the stiffer worms, the pacifica. Okay, so, weird.
	So why? Why would mucus be a good idea? What we think is that with A. pacifica, they can burrow like the dickens in any of that sediment, but their challenge is that when they are in that soft, goopy sediment, is maintaining the burrow walls. That being able to shore that up is not altogether a simple thing, and that mucus is something that is associated with that. For instance, if you go out and you look at the burrow walls of claparedi, you can see along here that they are in fact coated with mucus and that that's probably something to do with firming that up. 
	The point here is, okay, I've given you a lot of information about this. How does it fit into the bigger world of marine biology? Why should anybody care about this? Besides the fact that they're these fabulous worms, which should carry some weight, but the deal here is that people for a long time have wondered about how organisms live within the sediment. It's a fairly recent idea that the mechanical properties of the sediment, the physical properties, could they be influencing that. The work that has been done on that has totally been in the lab. It's beautiful work, but it's not been associated with any kind of ecology that's associated with organisms. By Rachel taking this project, she really had a great idea of making this really interesting comparison in a setting where she really could get some traction on what the differences were and how it mattered. 
	[inaudible 00:28:48] now. Now, the next quick story I want to tell you about is about Leah Lee and the burrowing sea cucumbers, Leptosynapta clarki. Leah went out to the False Bay and she got very interested in a very peculiar and in some ways underappreciated little organism. It's this guy, the sea cucumber. Looks like a worm, but it also has the appearance of being a nearly transparent worm. It is a diaphanously thin-walled critter. How is this animal, which is normally under the sediment, how is it actually extending its body and burrowing under the sediment? 
	Here's the first clue. You dig this thing up and in a few moments, what's happened is that extended body has retracted, and it's going to retract to about a fifth the length of the extended body. Think about that, what it would be like to have a body that you could extend five times. You want something over there? You just send your arm over there. [inaudible 00:30:03] light bulbs? Could stretch. It's just amazing to think about how our bones limit us, right? One of the things that Leah correctly realized is that the key to understanding this sort of amazing phenomena is what's going on with the mechanics of the body wall. 
	She began to make some measurements on the body wall. Now, the device that she used was a thing called a tensometer. Engineers are the ones who have all the knowledge about how to stress materials and to make measurements, and this is a typical kind of engineering device. What you do is you take the sample that you care about and you put it between these grips and then there's a sensor here, and the machine pulls or pushes on your sample, whatever you want. The sensor here records how much force. You can program this so that it can go fast or slow, and it also records how much the specimen changes its shape.
	If you took a piece of bone and you put it in that machine and you pulled on it, you would be applying a force, and it wouldn't surprise you that a bone doesn't change its shape very much. It's very stiff, and so it's not changing its strain very much, and so we see a pretty vertical line. That's a stiff sort of material. If you put in this machine a more flexible kind of material, like skin for instance, what you'd find is you'd be able to at much lower forces cause a greater extension of that material and it would be much more flexible. 
	One of the things that is interesting about a lot of biological, or at least some biological tissues, is that they don't do the classic kind of thing of either being stiff or flexible regardless of how ... Let me start that sentence again. One of the interesting things is that some organisms are made of tissues that are called viscoelastic, and so instead of giving always the same sort of stiffness regardless of the rate at which you put force on, their response to the force changes depending on how fast you're applying the force. That was really ... I'll try that again. All right? 
	The material that you know that is viscoelastic is silly putty. [inaudible 00:32:36] silly putty here, right? If I apply force to this fast, it's going to break clean. People think of silly putty, [inaudible 00:32:46] one of those things that only old people know about. Okay, so here we have silly putty. Now, if I take the same silly putty, but instead what I'm going to do is I'm going to apply force to it, low force, but very slowly. What happens is that it's more like a flute, extends and extends and extends. 
	It turns out the body wall of these little sea cucumbers are viscoelastic, that they can control that in some degree by ... In various ways with their nervous system, but what Leah discovered is that if she takes a piece of body wall or a whole animal and puts it in the tensometer, this is anesthetized so that the nervous system can't cause the muscles to contract, what happens is it is incredibly extensible. This is like having a body wall that is in some sense almost liquid. It can extend and extend and extend. That allows this weak little animal in a situation where it's in the sediment and can't generate a lot of force to nonetheless very slowly extend. 
	I'm going to show you an image here of Leptosynapta. Leptosynapta here is sitting on top of the cryolite. Cryolite is this totally cool mineral that has the same refractive index as water, and so it allows us to let something that is burrowing in sediment be seen. Here's a Leptosynapta up here and it's burrowing its anterior in here, and if I were to show you this as a realtime video, it would look like this. Leptosynapta are really, really slow, but if we turn this on, this is a time lapse that we have. Oops, sorry. This is a time lapse. 
	What it's doing here is slowly moving, only this is really fast for Leptosynapta. It's slowly moving these little particles out of the way. It's increasing the pressure in its body by contracting its muscles, and then it's very, very slowly extending the body wall, all at really low pressures, all with very low force. Takes a lot of patience to work with Leptosynapta, but ... What you should know is that in terms of biological materials, in terms of animal materials, Leah's measurements about the extensibility of this is twice as more extensible as any other published data on any kind of animal tissue. 
	Okay, another story. This is Joe Corcoran, and Joe is a current student at Swarthmore. He's worked with me at Friday Harbor for a couple of summers. Joe was not so interested in worms. Joe was interested in crabs. You can see there's some enthusiasm here. What he has in his hand is one of a couple of species that he has studied. This is a dungeness crab, and he was interested in how do crabs bury in the sand? Now, what I'm going to tell you about is a small piece of all that Joe has done in his work. He's done a lot of comparative work, both with different species and in different habitats, but I think you'll enjoy a different way of digging into the sediment.
	This is a realtime video of crab burying. Anytime you go out barefoot in the intertidal, that's a thing to think about. Okay, so how does this crab do it compared to other kind of things? Here's a blowup of that same crab that Joe was showing before. What you can see is that these limbs are a little bit different in their shape than most other crabs. For crabs that are more likely to be on the rocks, et cetera, their limbs are more likely to be sort of tubular, but these guys I think you can get a little sense of from this picture are pretty much flattened. They have a lot of surface area that's associated with them. The thing you can't see from this picture is that the angle at the posterior end of the body is quite narrow. 
	What these guys are doing is essentially using their limbs and their stiff body to move the sediment around. This is now a high-speed video. I've put blue lines on here so you can see where the animal begins. He anchors his back legs, and then he begins with his middle legs to simultaneously be sweeping the sediment around, and he's moving them under his body and essentially liquefying them in some sense. 
	One of the things that I hope you might be able to see from these blue lines is that he's essentially backing into the sediment. There's a series of leg movements where these big flat legs are sweeping the sand away. He's using the claws to push the body back in. Joe's been doing a lot of analyses of these, looking at animals of different sizes under different sedimentary conditions, and finding that this species does it somewhat differently than other species. It's also the best at moving through sediments. It's really kind of a sediment specialist. It's also true that small crabs can get into the sediment much more easily than big ones, and the sediment itself has rocks or cobble in it that this technique doesn't work as well. Wouldn't be surprised about that. [inaudible 00:39:29] end of it or not. My suggestion is that when you see Joe, you ask him for more details about his project. 
	The last critter, the last one I want to talk about is Justin [Swee 00:39:44] and the paper bubble snail, [inaudible 00:39:47]. What Justin is, he's standing out in that eelgrass bed, and you can't see it, but he's fascinated with something in the water. What he's looking at are these little snails. These are called bubble snails. They're called bubble snails because the shell here is so thin, it looks just like a little bubble. They are crawling around here on the surface of these eelgrass blades, where they are looking for mates.
	Essentially, what happens with these guys is that they find mates up on these eelgrass beds, blades, and they lay eggs. These eggs hatch, the larvae are in the water column for a short while, and then settle into the sediment, and the larvae, the juveniles live in the sediment for about eight or 10 months, and then the snails are mature and they come up on the surface. They have to move from the sedimentary part of the bay to the eelgrass in order to find partners. They form these long little snail trails, and part of this following behavior has to do with the fact that each of these animals is a hermaphrodite and each other animal is a potential mate. At this time of the year, what they're doing is they're finding mates and looking for places to lay their eggs. Here's sort of a blow-up of what that looks like.
	What Justin appreciated was that if you go out and you look at the eelgrass and the algae that's growing on it, what you see is that there's quite a bit of current going by and that the snails do a pretty good job of hanging onto that, but they have a problem if you think about it about how it is they hang onto the sediment when that same current is going by. If you can put out mucus, it can glue you to the sediment, but that sediment isn't attached to anything and so you could easily be displaced. 
	Here they are marching across the thing. They don't want to be displaced. They want to find their other partners and march in this parade. Here is a realtime video that Justin took, where these animals are crawling along the surface. They put out some amount of mucus, but then when a current comes, look what they do. They sort of dig their head down a little bit into the sediment and a sheet of mucus and sediment comes over their bodies. What you're seeing is them putting on an instantaneous weight belt. 
	What happens in the process of this is that the whole mass of the organism is increased. Here's the weight of the snail in terms of the mass gained just by crawling on top of the sediment, and then when they do the sheeting behavior, they increase their mass. I'm not going into the depth of Justin's project here, but he worked with animals in flow tanks and was able to show that by putting on these little sandy blankets, they are able to keep themselves from being blown away and that they have specific behaviors about orienting to the current as well, and so that they are using the sediment in a slightly different way. 
	What I hope you might have gotten from this is that when you are in a situation like this, you might think that you're there alone when in fact you're not alone. There are hundreds of species in that sediment. There are thousands and thousands of individuals, and they all have bodies that have interesting attributes and that have characteristics that allow them to meet the physical challenges of this situation. I hope that maybe your interest is piqued a little bit about things that are different than we are, and ready to take on these interactions of those organisms in physical situations. With that, I'll stop and ask for questions please.