Just a human, being

Posted on by Allison J. Gong

Recently I’ve been thinking a lot about our species’ relationship to the natural world. These musings have been brought on not only by my own impairment and inability to spend as much time in the field as I would like, but also by the current political climate in the U.S. Recent Executive Branch appointments and policy announcements make me fear that we, as a country, are going to be even more removed from the natural world than we currently are. This will have dire long-term consequences for all of us. Much has been made lately of federal cuts to spending on science and environmental protection. I am not qualified to address the economic aspects of cuts, but can speak to what I feel will be their effect on quality of life.

For several generations now, humans have become increasingly separated from the natural world around them. We live in cities surrounded by concrete and steel, most of us don’t grow or kill our own food, and we tend to view the natural world as “other,” differing from us in some fundamental way. Even among people who spend much of their leisure time outdoors, many at least occasionally view nature as something to be conquered–by climbing the highest peak, hiking the longest trail, visiting the deepest part of the ocean, or surfing the biggest wave. There isn’t necessarily anything wrong with testing your skills and challenging yourself to perform at the highest level possible. I do that all the time, by trying to learn the names and biology of the organisms I encounter in the wild. But if that’s what you’re doing every time you venture outdoors then you are missing out on something.

Sometimes you need to just be.

One of my graduate advisors, Todd Newberry, used to tell students when we went into the field to “get your face down where your feet are.” It was a simple phrase to remind students that none of the interesting stuff going on in the intertidal occurs at human eye level. And even things that you can see while standing up are very different when you observe them from the level at which they experience the world. For example, can you identify this very common and conspicuous animal from the intertidal at Natural Bridges?

7 March 2017
© Allison J. Gong

The observation skills that Todd taught us were the kind that reward patience and a certain ability to lose oneself in time. “Glance-and-go” was something that he taught us to despise as both lazy and weak, a mindset to be tolerated for a short time in rookies but completely unacceptable for anyone aspiring to the Varsity team. The true rewards of observation in the field come when you spend real time with the organisms, learning enough about them to imagine what their lives are like, and appreciating them for what they are instead of disregarding them for not being more like us.

In my experience there is something transcendent about simply being in nature. And I don’t mean temporarily occupying a bit of space that happens to be out-of-doors. I mean the act of immersing yourself, mentally as well as physically, in the natural world. I mean, instead of using your time outdoors to get from point A to point B or achieving some tangible goal such as bagging your limit or adding to your life list of species seen, stopping for a while and just being. Slowing down and stepping back from the frenzy of modern human life, even for a few minutes, allows you to notice things that ordinarily don’t catch your attention. Even seeing this happen second-hand is a lot of fun. One of the best things about taking students out in the field is hearing them exclaim, “I never noticed that before!”

I have to admit, though, that it’s not always easy to do this. Not everyone gets–or even wants–to make the Varsity team. Many people don’t have time in their busy lives to spend hours in the field every so often; certainly most don’t have the luxury of a job that requires spending time outdoors like I do. And of course there are those who just aren’t interested. That’s fine, too. After all, I’m not at all interested in the stock market, soccer, or stamp-collecting.

Now, back to that picture above. I bet that from this view, as you would see them from eye-level, you’d be able to made a good guess.

Organisms of the mid-intertidal at Natural Bridges
7 March 2017
© Allison J. Gong

These are the famous owl limpets, Lottia gigantea. They are the largest limpets on our coast, and are notable not only for their size (up to 10 cm long) but also for some rather extraordinary behavior. These large individuals, which occupy suspiciously blank areas of the mid-intertidal at Natural Bridges, are all females. The limpets are very territorial: when immersed at high tide they will cruise over the area that they monopolize and push or scrape off any interlopers such as other limpets, barnacles, or newly settled larvae.

An owl limpet (L. gigantea) in her farm at Natural Bridges
7 March 2017
© Allison J. Gong

See those zig-zaggy marks no the rock in the photo above? The owl limpet is also a farmer. As she’s patrolling her territory she uses her radula to scrape off the film of algae that grows on the rock. It takes a while for the algal film to develop, so the limpet restricts her grazing to one area at a time. She is, in effect, manipulating her environment to produce food. When humans do this we call it agriculture. Why not use the same term when a snail does it?

These Lottia farms are exactly the kind of thing that people overlook, and even stand in, without noticing that they are there. In the intertidal, as in many natural places, you don’t really see what’s going on until you slow down, let yourself just be, and get your face down where your feet are. You might be surprised at how much you can see.

A different sort of hatching

Posted on by Allison J. Gong
Newborn bald sculpin (Clinocottus recalvus) hatchlings
22 February 2017
© Allison J. Gong

My bald sculpins have begun hatching! Their egg mass has been disintegrating over the past few days and I couldn’t tell if that was because they were dying or hatching. Yesterday I was able to spend some time looking at them and was surprised to see that a few little pink blobs had wiggled their way out of the egg mass while I was manipulating it. Baby fishies! Well, they’re still mostly yolk, but each yolk has a baby fish attached to it. They flit around quite a lot and are difficult to photograph. I had to put this trio in a depression slide, the macro photographer’s trick of making the universe smaller so the creature can’t swim too far away.

Bald sculpin (C. recalvus) hatchling
22 February 2017
© Allison J. Gong

This little fish was cooperating with me, so I carefully placed a coverslip on its drop of water and took some video. The first part was shot through the dissecting microscope with epi-illumination from a fiber-optic light, which shows the surface details. The second clip was taken through the compound microscope with trans-illumination; this kind of lighting doesn’t show any of the three-dimensional structure of objects but does a wonderful job with transparent objects like larval fish.

I like that the baby fish have spots on their yolk sacs as well as the top of the head. And from the second half of the video it appears that they don’t yet have a gut, at least not one that I can see. For the time being they don’t need a gut, as they’re surviving off the energy stored in the yolk sac, but once the yolk has been absorbed they will have to start feeding. At that point they’ll need to have complete guts. I imagine they will be hungry, and hope I have something they’ll be able to eat.

How big are these baby fish, you ask? The smallest ones were about 2 mm long, and the biggest one was twice the size, with a correspondingly smaller yolk.

Bald sculpin (C. recalvus) hatchling
23 February 2017
© Allison J. Gong

And yesterday I caught some time-lapse video of a baby hatching from its egg. Why have I never played with the time-lapse function on my phone before? It’s really cool.

For now I’m keeping the babies in a mesh container, separated from their father so he cannot eat them. I don’t think I’ll end up with more than a couple dozen hatched larvae, as the egg mass has begun to decompose and many of the embryos have died inside their eggs. And no doubt some of the larvae that I’ve rescued already will die. I figure I have a few days before I need to worry about feeding the survivors. After that, who knows? Your guess is as good as mine.

Metamorphosis

Posted on by Allison J. Gong

It has been a few weeks since I posted about my most recent batches of urchin larvae. Some strange things have been happening, and I’m not yet sure what to make of them. It would be great if animals cooperated and did what I expect; somehow that never seems to be the case. The upshot of all this uncertainty is that there is always something new to learn. I, for one, am not going to complain about that.

One noteworthy thing to report is that my hybrids all died, very quickly and unexpectedly. They had been racing through development and on the dreaded Day 24 they looked great.

Hybrid larvae of purple urchin (Strongylocentrotus purpuratus) eggs fertilized by red urchin (Mesocentrotus franciscanus) sperm, age 24 days.
23 January 2017
© Allison J. Gong

And the next time I changed their water, they were all dead. So much for the hybrid vigor I had written about earlier. Teach me to get cocky and think I know what’s going on.

Fast forward to Day 52, and some of the cultures are still going strong. I originally set up four matings, and at least some individuals from each are alive. One thing that seems to happen when I start multiple batches of larvae at the same time is that the batch with the fewest numbers does the best. This time my F3xM1 mating was always the least dense culture, but some of them have already begun and completed metamorphosis. And the ones that are metamorphosing are the ones being fed what I expected to be the less desirable food source. As I said, not much of this whole experience is making sense.

The good thing is that I have an opportunity to observe these larveniles in action. As long as they don’t get arrested in this neither-here-nor-there stage, they should soon join their siblings as permanent inhabitants of the benthos.

This video contains short clips of three different larveniles. I’ve arranged the clips from earlier to later stages of metamorphosis. Although these are three separate individuals, you can imagine that each one goes all of these stages.

Having both tube feet (for crawling around the benthos) and ciliated bands (for swimming in the plankton) make these animals unsuited for either habitat. They have gotten very heavy and sink to the bottom, but it doesn’t take much water movement to knock them off their five little tube feet. It always amazes me that teensy critters like this, so fragile and easily killed, manage somehow to stick in the intertidal and survive long enough to be grown-up urchins on their own. And yet some of them will. I’ve seen it happen.

A few days make all the difference

Posted on by Allison J. Gong

Almost a week ago, my sculpin eggs were doing great. The embryos had eyes and beating hearts and were actively squirming around inside their eggs. A few of them had died but overall they seemed to be developing well. I had high hopes that they would continue to do so, and began to think of what I’d need to do once they hatched.

Today the egg mass is 19 days old, and things aren’t going so well.

Bald sculpin (Clinocottus recalvus) egg mass, age 19 days.
18 February 2017
© Allison J. Gong

Many of the embryos on the outer edges have died, and all that remains of them are the tattered remnants of their eggs. Those opaque white eggs have been dead for a while and the pale pink shredded eggs died more recently, in the last day or so. I took a quick peek at the egg mass yesterday, and it looked much healthier than it does today. I’d guess that all told about 30% of the embryos have died since development began.

Bald sculpin (Clinocottus recalvus) egg mass, age 19 days.
18 February 2017
© Allison J. Gong

The embryos that are still alive seem to be fine. Their eyes can now move around independently but I still don’t know what, if anything, they can see. Their bodies continue to grow and now they have spots on their tails as well. I can make out where the heart is because I can see it beating, but I can’t discern any of the other internal organs. If the lighting is just right I think I can see pectoral fins on some of the embryos, which are too faint and indistinct to photograph. The baby fish are still swimming around inside their eggs, too.

Question of the Day: What caused the eggs’ condition to deteriorate so rapidly?

Well, I can think of a couple of explanations.

Survivorship curves
Source: Wikimedia Commons, 2017

Explanation #1: Not everybody survives long enough to hatch. Sculpins and other fishes that lay large numbers of eggs are generally described as having a Type III survivorship curve (see right). These organisms have lots of babies, few of which survive to adulthood; probability of death is highest in the youngest age classes. Individuals that do make it to adulthood experience much lower mortality and have a decent chance of surviving into old age. In an egg mass like this, each egg has a very small probability of eventual survival to adulthood. To paraphrase an old saying, if they all survived then the world would be covered in bald sculpins. Obviously that’s not the case–and that’s a good thing!–so most of these eggs are not going to make it in the long run even in the best of circumstances.

Explanation #2: Crappy water quality. A very strong storm blasted through the area yesterday, complete with wind gusts to about 50 m.p.h. and 1-2 inches of rain, depending on location. All of this rain generates a lot of surface runoff, which carries mud and debris (think bushes and trees as well as garbage) into Monterey Bay. Plus, the high winds and turbulent swell stir up the bottom in shallow areas, resulting in brown, turbid water. This is the water that we use in the lab, and it’s our only source of seawater. Today the water was visibly cloudy. At least it seems to be just sediment, though, and not another phytoplankton bloom.

Poor water quality could affect the sculpin eggs if the sediment settles out on the surface of the egg mass, impeding gas exchange between the eggs and the surrounding water. In the field these eggs would be subjected to strong turbulence from the bashing waves, which would keep them clean and the water highly oxygenated. Some species of fish guard their egg masses and blow water on them to clear them of both sediment and fouling organisms. I hadn’t seen the parents of my sculpin eggs caring for their offspring at all, but I have been rinsing off the egg mass every day. Maybe I haven’t been able to keep the eggs clean enough. It does seem to be the eggs on the outside of the mass that are dying, so cruddiness might very well be part of the problem.

I’ll look at them again tomorrow and see if anything has changed. The news could be either good or bad, and I honestly don’t know what to expect.

Have a heart

Posted on by Allison J. Gong

Back in mid-December I collected a couple of small intertidal fishes and brought them back to the lab for observation and identification. Then the female laid a batch of eggs, which I’ve been watching ever since. Today the eggs are 15 days old. They are developing pretty quickly, I think, at ambient seawater temperatures of 12-13.5°C. Some of the changes can be seen with the naked eye, while others are visible only with some magnification.

Here’s a timeline of development for the first couple of weeks in the earliest life of bald sculpins.

Day 4: The egg mass is clean and the eggs are clear and pink. The very young embryo can be faintly seen as a paler pink strip lying on top of the darker pink yolk, which fills most of the internal volume of the egg. There are also some oil droplets associated with but not part of the yolk.

Eggs of the bald sculpin (Clinocottus recalvus)
3 February 2017
© Allison J. Gong

It wasn’t until this day that I was convinced the eggs were alive. Until then they looked like undifferentiated pink blobs with not a lot going on.

Day 7: Today they had eyes! And they were swimming around inside their eggs!

Eyed larvae of the bald sculpin (Clinocottus recalvus)
6 February 2017
© Allison J. Gong

Day 10: Today the eyes look more like fish eyes and are taking on a silvery sheen. Black pigment spots are forming along the dorsal surface of the embryos, and the yolk is noticeably smaller. The eggs are starting to look dirty to the naked eye, due to the darkening eyes and pigment spots.

Larvae of the bald sculpin (Clinocottus recalvus), age 11 days
10 February 2017
© Allison J. Gong

Today was the first day I could see their heartbeats! It was surprisingly difficult to capture the beating hearts with the camera.

Day 15: Some of the eggs have died, becoming opaque and hard. A few have broken open and are empty. The overall color of the egg mass is paler, as the larvae are consuming their yolks. The black pigment spots are becoming more prominent and seem to be concentrated on the top of the head.

Larvae of the bald sculpin (Clinocottus recalvus), age 15 days
14 February 2017
© Allison J. Gong

They look like baby fish now! They’re still flipping around inside their eggs and I think may be responding to light. They don’t seem to like it when I shine the light on them.

I’ve put together a short video of the eggs at various stages of development so far.

Let me know what you think!

Eggs of a different sort

Posted on by Allison J. Gong

Back in mid-December I collected some urchins at Davenport Landing. Some of these urchins are the parents of the larvae that I’m culturing and observing now. Towards the end of the trip I flipped over some surfgrass (Phyllospadix torreyi) and saw two fish, obviously sculpins, huddled together; they had been hiding in the Phyllospadix and waiting to be submerged when the water returned with the high tide. I have a probably inordinate fondness for intertidal fishes, and love catching sculpins. These were too big to be fluffies (Oligocottus snyderi) but I couldn’t pin down an ID any closer than that. I brought them back so I could take a closer look at them in the lab.

Trying to key out the intertidal sculpins in California is an activity fraught with danger. There are about a dozen species that are likely, plus more that are occasionally encountered in the intertidal. When identifying fishes ichthyologists use meristics, or counts of things such as scales along the lateral line or hard spines in the dorsal fin, to differentiate species. Since you can’t very easily count the number of spines in the dorsal fin while observing a fish thrashing around in a ziploc bag, I needed to get them under the dissecting scope.

Here is a picture that I took of the fish this morning. This is the same posture they had when I first saw them in the field. I think the male (paler fish on the right) is guarding the darker female. Oh, and while I’m at it, I should say that skin color is an unreliable characteristic to use when IDing sculpins. Their skin color can and does change very rapidly, depending on the surroundings and the fish’s emotional state.

3 February 2017
© Allison J. Gong

See those little tufts on the top of the head of the fish on the left? Those are called cirri. When I was keying out these guys I narrowed down the options to either bald sculpin or mosshead sculpin, and the distribution of the cephalic cirri was the final determining factor. Mosshead sculpins (Clinocottus globiceps) have cirri densely scattered over the entire head, while in balds (Clinocottus recalvus) the cirri extend forward only to just behind the eyes; in other words, bald sculpins have no cirri between the eyes or anywhere anterior to the eyes. In my fish the cirri clearly do not extend forward of the eyes, making these bald sculpins.

Bald sculpin (Clinocottus recalvus) peering at the camera with justifiable suspicion.
3 February 2017
© Allison J. Gong
Bald sculpin egg mass
3 February 2017
© Allison J. Gong

It usually takes animals a week or two to settle in after being collected from the field. After a couple of weeks the fish were eating regularly and hungrily. Sculpins don’t have an air bladder, which helps keep them from getting washed out of their home pools as the tide moves in and out, and tend to sink if they aren’t swimming. They can, however, swim very well. Once they got used to the idea of food coming at them from above they would start looking up when I removed the lid to their tank. When they’re really hungry they will swim up and attack the food, ripping it from my forceps. Otherwise I dangle food in front of their faces and they take it a little more gently. Now they are both eating well.

One of the sculpins went off its feed last week and then surprised me by producing a mass of pink eggs. She had deposited the eggs on the underside of the cover instead of on the surfgrass I have in the tank. No wonder she hadn’t been eating; with all those eggs inside her there would be no room for food! I decided to keep the eggs and see what, if anything, would happen with them.

Eggs of the bald sculpin (Clinocottus recalvus)
3 February 2017
© Allison J. Gong

Each of the eggs is about 1mm in diameter, and they are indeed pink. They are stuck together in a pretty firm mass. I peeled it off the cover of the tank and the whole mass remained intact. I can easily pick up the mass and put it into a bowl for viewing under the dissecting microscope. At first I could see that the eggs contained a large yolk and some smaller oil droplets but I couldn’t tell whether or not they were alive. I cleaned them off to remove any dirt or scuzz, then returned them to the tank, hoping the parents wouldn’t eat them. Over the first several days I couldn’t see any change in the eggs except some of them became opaque and white, obviously dead. And it looked like maybe the stuff inside the eggs was shifting around a bit, but I wasn’t sure if that was something good going on or the beginning of decomposition. The egg mass continued to stick together, though, which I took as a positive sign.

Then yesterday when I looked at the eggs I was able to convince myself that, yes, something is happening inside them. I saw tiny little fish bodies, complete with bulbous rudimentary heads, developing on the yolks!

Developing bald sculpin (C. recalvus) embryos
3 February 2017
© Allison J. Gong

Each egg is a pale pink sphere containing a darker pink yolk. At this early stage of development the yolk takes up most of the interior space of the egg. Lying across the yolk, with a swelling at one end, is the developing fish embryo. The swelling is the head. Even at this stage the three body axes (anterior-posterior, dorsal-ventral, and left-right) have been established for quite a while. The yolk will shrink as the energy stores within it are consumed by the developing embryo. I don’t know if sculpins hatch as larvae (i.e., with a yolk sac still attached) or as juveniles (after the yolk sac has been completely consumed). I hope I get to watch these eggs and see!

Beginnings and leavings

Posted on by Allison J. Gong

A few days ago I was in the intertidal with my friend Brenna. This most recent low tide series followed on the heels of some magnificently large swells and it was iffy whether or not we’d be able to get out to where we wanted to do some collecting. Our first day we went up to Pistachio Beach, just north of Pigeon Point, where the rocky intertidal is bouldery and protected by some large rock outcrops.

Pigeon Point lighthouse, viewed from Pistachio Beach.
27 January 2017
© Allison J. Gong
27 January 2017
© Allison J. Gong

So while the swell was indeed really big, we were pretty well protected in the intertidal. The Seymour Center has a standing order for slugs, hermit crabs, and algae. I was easily able to grab my limit (35) of hermit crabs over the course of the afternoon, and while it’s too early in the season for the algae to do much I had my sluggy friend with me to take care of finding nudibranchs, which left me free to let my attention wander as it would.

Codium setchellii at Pistachio Beach.
27 January 2017
© Allison J. Gong

The very first thing to catch my eye as we go out there was the coenocytic green alga Codium setchellii, which I wrote about last time. I’ve seen and collected C. setchellii from this site before, but don’t remember seeing it in such large conspicuous patches. I need to review what I learned about the phenology of various intertidal algae, but here’s a thought. Maybe Codium is an early-season species that gets outcompeted by the plethora of fast-growing red algae later in the spring. Red algae were present at Pistachio Beach but not in the lush (and slippery!) abundance that I’ll see in, say, June. I’m willing to bet that Codium will be less abundant in the next few months.

Leptasterias sp. at Pigeon Point.
24 April 2016
© Allison J. Gong

In my experience, the six-armed stars of the genus Leptasterias have always been the most abundant sea stars on the stretch of coastline between Franklin Point and Pescadero. Even though they are small–a monstrously ginormous one would be as large as the palm of my hand–they are very numerous in the low-mid intertidal. I’ve seen them in all sorts of pinks and grays with varying amounts of mottling. Alas, I don’t know of any really reliable marks for identifying them to species in the field.

Unlike other familiar stars, such as the various Pisaster species and the common Patiria miniata (bat stars), which reproduce by broadcast spawning their gametes into the water, Leptasterias is a brooder. Males release sperm that is somehow acquired by neighboring females and used to fertilize their eggs. There isn’t any space inside a star’s body to brood developing embryos, so a Leptasterias female tucks her babies underneath her oral surface and then humps up over them. Leptasterias also humps up when preying on small snails and such, so that particular posture could indicate either feeding or brooding.

Here’s a Leptasterias humped up on a rock, photographed last spring:

Leptasterias sp. at Pigeon Point.
5 May 2016
© Allison J. Gong

The only way to tell if a Leptasterias star is feeding or brooding is to pick it up and look at the underside. I did that the other day and saw this:

Brooding Leptasterias sp. star at Pistachio Beach.
27 January 2017
© Allison J. Gong

Those little orange roundish things are developing embryos. While the mother is brooding she cannot feed, and can use only the tips of her arms to hang onto rocks. Don’t worry, I replaced this star where I found her and made sure she had attached herself as firmly as possible before I left her. In a few weeks her babies will be big enough to crawl away and she’ll be able to feed again.

Looks like the reproductive season for Leptasterias has begun.

The next day Brenna and I went to Davenport, again hoping to get lucky despite another not-so-low tide and big swell.

Davenport Landing Beach and adjacent rocky areas.
© Google Earth

Davenport Landing Beach is a popular sandy beach, with rocky areas to the north and south. The topography of the north end is quite variable, with some large shallow pools and lots of vertical real estate to make the biota very diverse and interesting. The big rocks also provide shelter from the wind, a big plus for the intrepid marine biologist who insists on going out even when it’s crazy windy. The southern rocky area is very different, consisting of flat benches that slope gently towards the ocean, with comparatively little vertical terrain. The southern end of the beach is always more easily accessible, which is why I almost always go to the north. But this day the north wasn’t going to happen. The winter storms had washed away at least a vertical meter of sand between the rock outcrops. That and the not-so-low tide combined for conditions that made even getting out to the intended collecting site a pretty dodgy affair. So Brenna and I trudged across the beach to the south.

28 January 2017
© Allison J. Gong

Along the way we saw lots of these thumb-sized objects on the beach. At first glance they look like pieces of plastic, but after you see a few of them you realize that they are clearly (ha!) gelatinous things of biological origin. They are slipper-shaped and you can stick them over the ends of your fingers. They have a bumpy texture on the outside and are smooth on the inside.

Any guesses as to what they are?

Pseudoconch of Corolla spectabilis, washed up on Davenport Landing Beach.
28 January 2017
© Allison J. Gong

These funny little things are the pseudoconchs of a pelagic gastropod named Corolla spectabilis. What is a pseudoconch, you ask? If we break down the word into its Greek roots we have ‘pseudo-‘ which means ‘false’ and ‘conch’ which means shell. Thus a pseudoconch is a false shell. In this case, ‘false’ refers to the fact that this shell is both internal (as opposed to external) and uncalcified.

The animal that made these pseudoconchs, Corolla spectabilis, is a type of gastropod called a pteropod (Gk: ‘wing-foot’). Pteropods are pelagic relatives of nudibranchs, sea hares, and other marine slugs. They are indeed entirely pelagic, swimming with the elongated lateral edges of their foot. Like almost all pelagic animals, Corolla has a transparent gelatinous body. Even their shell is gelatinous, rather flimsier than most shells, but it serves to provide support for the animal’s body as it swims.

You can read more about Corolla spectabilis and see pictures and video here.

Why, you may be wondering, do the pseudoconchs of C. spectabilis end up on the beach, and where is the rest of the animal? The body of Corolla and other pteropods is soft and fragile. When strong storms and heavy swells seep through the area, the water gets churned up and pteropods (and other pelagic animals) get tossed about and shredded. This leaves their pseudoconchs to float on currents until they are either themselves demolished by turbulence or cast upon the beach. Corolla is commonly seen in Monterey Bay, and it is not unusual to find their pseudoconchs on the beaches after a series of severe storms.

Brenna and I were wondering if we could preserve the pseudoconchs somehow. I took several back to the lab and tried to dry them, thinking that they might behave like Velella velella does when dried. Unfortunately, the next day they had shriveled into unrecognizable little blobs of dried snot, and the day after that they had disintegrated completely into piles of dust. Maybe drying them more slowly would work. Something to consider the next time I run across pseudoconchs in the sand.

Simply green

Posted on by Allison J. Gong

A few days ago I told my friend Brenna that I’d hunt around in the marine lab for a bit of a green alga that she wants to press. I had a pretty good idea of where to look, only the animals I’d seen it on had been removed from the exhibit hall. I asked for and got permission to examine the animals behind the scenes. And fortunately I had remembered correctly, and I was able to pick off some nice clumps of dark green stuff.

Bryopsis corticulans is a filamentous green alga. It grows to about 10 cm in length and is a dark olive color. When emersed it sometimes looks almost black. I’ve seen it in the intertidal in a few places, where at low tide it resembles nothing so much as a shapeless slime. It’s very difficult to see the beauty of organisms when they’re out of their natural element, which in this case is water.

B. corticulans emersed during low tide at Mitchell’s Cove.
8 June 2016
© Allison J. Gong

But see how pretty it is when submerged?

Bryopsis corticulans
23 January 2017
© Allison J. Gong

One of the reasons I love the algae is their very inscrutability. I enjoy discovering the beauty of organisms that, at first glance, don’t look like much. Many of the filamentous algae, both the greens and the reds, have a delicate structure that requires close examination to be appreciated. Fortunately, I have access to microscopes, so close examination is very easy.

The thallus of B. corticulans is relatively simple, consisting of a bipectinate arrangement of filaments.

Apical tip of Bryopsis corticulans.
23 January 2017
© Allison J. Gong

Here’s a closer view:

Thallus of Bryopsis corticulans.
23 January 2017
© Allison J. Gong

This is a shot of the main axis and side filaments. The small green blobs are chloroplasts. One thing to notice is that there are no crosswalls separating any of the filaments. That’s because the thallus is coenocytic, essentially one large cell with a continuous cytoplasm. Coenocytic cells are common in fungi, the red and green filamentous algae, and a few animals. In animals, coenocytic cells are often referred to as syncytial. They can arise in one of two ways: (1) adjacent cells fuse together; or (2) nuclear replication occurs as usual during normal mitosis but cytokinesis (division of the cytoplasm) does not. However the syncytium arises, it can result in very large cells. Even though B. corticulans itself is a small organism, some algae in the Bryopsidales consist of single cells that can be over 1 meter long!

Sometimes things that appear simple at first glance conceal a deeper complexity when you look more closely.

Hope for the future

Posted on by Allison J. Gong

It has been almost three and a half years since I first documented seastar wasting syndrome (SSWS) in the lab. Since then many stars have died, in the field and in the lab, and more recently some species seem to be making a comeback in the intertidal. This circumstantial evidence may not be reason enough to conclude that the epidemic is over, but I think there is reason to be hopeful. Any disease outbreak eventually runs its course, and despite its death toll there are always at least some survivors. And I have an individual star that was very sick but seems to be recovering.

In September of 2015 one of my bat stars (Patiria miniata) developed the first tell-tale lesion of SSWS on its aboral surface. At the time the lesion was small (less than 10 mm in diameter) and superficial. Knowing that SSWS starts with minor symptoms and rapidly progresses to something horrific within a day or so, I wanted to keep an eye on this star. It held the same morbid fascination as a car accident or any other impending catastrophe.

5 September 2015

Bat star (Patiria miniata) with small aboral lesions.
4 September 2015
© Allison J. Gong
Dermal lesion on the aboral surface of a bat star (P. miniata).
5 September 2015
© Allison J. Gong

24 November 2015

By November 2015 the main lesion hadn’t grown much but a few others had developed. The star still wasn’t acting sick and was eating every once in a while, although it occasionally ignored the food that I offered.

Bat star (P. miniata) with aboral lesions.
24 November 2015
© Allison J. Gong

So far, so good. I was thinking that the star doesn’t look too much worse, so maybe it wouldn’t keep getting sicker. I checked on it regularly, offered food a few times a week, and left it alone.

4 May 2016

Several months later I noticed that the first lesion had gotten much deeper. The outer dermal layers had been completely compromised, exposing the animal’s internal organs (gonad and digestive caecum) to the external environment. This was bad, very bad. Even in stars, internal organs are supposed to be internal, except when stars extrude their stomachs to feed.

Bat star (P. miniata) with deep aboral lesion.
4 May 2016
© Allison J. Gong
Lesion on aboral surface of a bat star (P. miniata). Note the internal structures that are exposed to the surrounding seawater.
4 May 2016
© Allison J. Gong

This was the point in time when things started going south. The star lost the ability to maintain its internal turgor pressure and became lethargic and floppy. It stopped eating, or even responding to food. It spent most of its time in a corner of the seawater table where it lives, although a few times I saw it wrapped around one of the hoses that feeds the table. However, its body never started disintegrating the way I’d seen with other SSWS victims.

19 January 2017

Fast-forward another several months. About a month ago the sick bat star began perking up a bit when I placed food near the tip of one of the arms. A week later it actually wrapped its arm around the food, and I assume ate it. It has since been eating about once a week, after fasting for at least eight months. I began to think it would recover.

Today I had some time to photograph the star again, and it really appears to be doing much better!

Bat star (P. miniata) with healing lesions.
19 January 2017
© Allison J. Gong

The lesions are apparently healing over; at any rate, the internal organs are no longer exposed to the outside. The body margin between the arms has a few small divots, but they look superficial. Lately the star has been more active, too, cruising around the table instead of hunkering down in a corner. I’m going to keep feeding it to see if it continues to improve.

One of the most remarkable things about many animals with a decentralized nervous system, such as echinoderms and cnidarians, is their ability to regenerate lost parts and repair damage to their bodies. This bat star is a prime example. It has been sick for almost a year and a half now, and for at least half that time it hasn’t eaten. Yet it somehow had the metabolic reserves to heal a major wound to its body wall. That’s some astounding resilience there. I am very impressed, and you should be, too.

The hybrids are winning!

Posted on by Allison J. Gong

Although at this stage it’s a close race. Two and a half weeks ago I spawned sea urchins in the lab, setting up several purple urchin crosses with the hope of re-doing the feeding experiment that I lost this past summer when I was on the DL (that’s Disabled List, for those of you who don’t speak baseball). I was also fortunate enough to set up a hybrid cross, fertilizing purple urchin (Strongylocentrotus purpuratus, or “Purp”) eggs with red urchin (Mesocentrotus franciscanus, or “Red”) sperm. I would have done the reciprocal hybrid cross (red eggs by purp sperm) as well if I’d gotten any of female red urchins to spawn. However it wasn’t really spawning season for the reds, and I consider myself lucky to have persuaded that one male to release some sperm for me.

This is the first time that I’ve tried to raise the hybrid larvae, although I know it can be done because my colleagues Betsy and John did it many years ago, before I came to the marine lab. All of my larvae are the exact same age and are being raised side-by-side, so I can make direct comparisons between the Purp by Purp crosses and the Purp by Red hybrids. Incidentally, when speaking or writing about a hybrid cross the convention I’ve adopted is to reference the female parent first, so when I say Purp by Red I mean a Purple eggs fertilized by Red sperm. A Red by Purp hybrid would logically result from red urchin eggs fertilized by purple urchin sperm.

My experience raising sea urchin larvae is that things almost always go well for the first 48 hours or so; most (but not all) of the fertilized eggs develop into embryos and undergo the crucial processes of gastrulation and hatching. In some cultures the hatching rate is close to 100%. After that there’s a window of 3-4 days when cultures can crash for no apparent reason, although food availability or quality may be a factor. If the larvae make it past their first week of post-hatching life they generally cruise along until the next danger period which occurs at about 24 days. I change the water in the culture jars and observe the larvae under the microscope twice a week.

Today the larvae are 18 days old. It’s a little early for that second mortality period, but some of the Purp by Purp cultures never really took off. The larvae don’t seem to be growing or developing as quickly as I’m used to. Perhaps this has to do with lower water temperatures, especially after the prolonged period of high temps in 2014-2015. In any case, two of the four Purp by Purp crosses are doing well and the other two are just hanging in there.

There are two things I can see with the naked eye that give me a heads-up when cultures are crashing: the first sign is an accumulation of debris at the bottom of the jar and the second is an absence of larvae in the water column. The debris can be due to excess food, a build-up of fecal matter (not usually the case, as I’m pretty good at doing the water changes on time), the disintegration of larval bodies, or some combination thereof. If the water column is clear then the culture has already crashed and everybody is dead.

Today one of my jars had crashed. The water column was very clear and there was a lot of fluff at the bottom of the jar. I’d been wondering if I could figure out what the fluff was made of, so I sucked up a bit in a pipet and examined it under the microscope. I thought I’d see dead algal cells or pieces that look like defecated algal cells. This is what I saw:

18 January 2017
© Allison J. Gong

Silly me. I had forgotten that the corpses of pluteus larvae would disintegrate pretty quickly, leaving behind only the skeletal rods. The rods get all tangled together and trap the organic stuff, which is probably a mixture of uneaten and defecated algal cells and the soft tissues of the larval bodies. This explains the clear water column in the jar.

While the Purp by Purp larvae have had mixed success so far, the Purp by Red hybrids have been doing well. From the outset they appeared to be more robust than the Purps, and even though the fertilization rate was only about 50% the post-hatching mortality seems low. The hybrid larvae are also larger than the Purps, and are developing more quickly. In the two photos below the scale bar indicates 100 µm.

Pluteus larva of Strongylocentrotus purpuratus, age 18 days.
17 January 2017
© Allison J. Gong
Pluteus larva of a hybrid cross between S. purpuratus and Mesocentrotus franciscanus, age 18 days.
17 January 2017
© Allison J. Gong

The hybrid larva is about 10% larger than the Purp larva. Other than that they look similar, but to me the hybrid larva seems farther along the developmental process: its arms are proportionally longer and have a more mature look (although I don’t have any way to describe that to a naive observer). There’s something about the gestalt of the animal that makes me think it’s more robust than the Purp individual.

We’ll see how the pure Purps and the hybrids do from here on. I actually have the Purp larvae divided up into different feeding treatments, which I may discuss in a future blog post. In the meantime I’m trying to baby the hybrid larvae as much as possible, to maximize their probability of successful metamorphosis in six weeks or so.