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In defiance of post-nasal drip and an ominous tickle at the back of my throat, I got up early again this morning and went out on the low tide. I skipped yesterday's low tide in favor of getting a little more sleep, thinking that it would help me fight off this incipient summer cold, but I didn't want to miss two of the three intertidal trips I had planned for this weekend. So I made the quick drive up to Davenport Landing, where low tide was at 06:4o.

The first thing I noticed when I got down to the beach was that the algae have started piling up. There were drifts that I sank into almost knee-deep. Fortunately they hadn't really started decomposing yet, so the smell wasn't too bad. That will change if it stays warm and the high tides don't wash any of the algal detritus back out to sea.

Looking back at Davenport Landing beach, from the north. 2 August 2015. © Allison J. Gong
Looking over piles of algal detritus towards Davenport Landing beach, from the north. 2 August 2015.
© Allison J. Gong

It's treacherous stuff, that algal duff. It covers up deep holes and slippery rocks, so each footstep becomes an adventure. Because it has been so warm I had considered going out in shorts and surf booties, but more than once this morning I was glad to be wearing my hip boots.

It was a busy day for nemertean worms. Nemerteans are unsegmented, slimy, predatory worms that feed by shooting out a proboscis and wrapping it around prey. In some nemerteans the proboscis is armed with a stylet that injects toxins to help immobilize prey, which are often small polychaete (segmented) worms. Nemerteans are not uncommon, but are often inconspicuous and easily overlooked. None of the ones that I saw today were actively hunting.

Nemertean worm (Paranemertes peregrina) at Davenport Landing, 2 August 2015. © Allison J. Gong
Nemertean worm (Paranemertes peregrina) at Davenport Landing, 2 August 2015.
© Allison J. Gong

As you can see, the body of this worm is not segmented. However, it has the same body wall musculature that you'd find in the polychaetes, which are the segmented marine worms. It uses the muscles to alternately contract and elongate the body and move forward. In most nemerteans neither the head nor the tail end is particularly distinguishable, but in worms you can usually tell the anterior (head) end by the direction of locomotion. Here's a video:

Continuing to play with the 'microscope' setting on my camera, I took this picture of a chiton (Mopalia muscosa):

Mopalia muscosa at Davenport Landing, 2 August 2015. © Allison J. Gong
Mopalia muscosa at Davenport Landing, 2 August 2015.
© Allison J. Gong

I'm still learning how to make that compromise between super-macro and depth of field on this setting. The chiton in the above photo is about 4 cm long so I wasn't zoomed in terribly far, and I like how it is in focus but some of the other critters are as well.

On the reef to the north of Davenport Landing beach there's a large pool that gets to a bit more than knee deep on me, and is cut off from the ocean during low tide. This pool has proven to be a great place to practice my underwater picture taking. The past couple of times I've come out here I've seen schools of surfperches swimming in this pool. The school contains large individuals (about as long as my hand) and smaller ones that I think are the babies of the big ones. I haven't been able to catch one--for some reason I've never included a dipnet in my collecting gear, preferring to catch sculpins with my hands--but I think they are shiner surfperches (Cymatogaster aggregata).

Before trying to photograph the fishes underwater, I shot some video from above:

It turns out that photographing fish underwater isn't as easy as I thought it might be. Surfperches are pretty skittish and I couldn't get as close to them as I wanted. However if I stood still for a minute or so they forgot about me and would resume their normal behavior. In the meantime I did sort-of-accidentally take some cool pictures of the pool from below the surface.

Large tidepool at Davenport Landing, 2 August 2015. © Allison J. Gong
Large tidepool at Davenport Landing, 2 August 2015.
© Allison J. Gong
Large tidepool at Davenport Landing, 2 August 2015. © Allison J. Gong
Large tidepool at Davenport Landing, 2 August 2015.
© Allison J. Gong

And finally, fish!

Shiner surfperches in large tidepool at Davenport Landing, 2 August 2015. © Allison J. Gong
Shiner surfperches (Cymatogaster aggregata) in large tidepool at Davenport Landing, 2 August 2015.
© Allison J. Gong

Last, but certainly not least, in this same large pool I found several anemones. The most brightly colored are the Anthopleura artemisia. I love how their tentacles can be such a vibrant translucent orange or purple, or the oral disc can have that deep saturated red color.

Anthopleura artemisia at Davenport Landing, 2 August 2015. © Allison J. Gong
Anthopleura artemisia at Davenport Landing, 2 August 2015.
© Allison J. Gong
Anthopleura artemisia at Davenport Landing, 2 August 2015. © Allison J. Gong
Anthopleura artemisia at Davenport Landing, 2 August 2015.
© Allison J. Gong

Hard to believe that these animals are the same species, isn't it? Then again, to an alien scientist studying humans it might be hard to believe that a Viking, an Australian aboriginal and I (an Asian-American) are the same species. It's all simply a matter of perspective.

This morning I collected another plankton sample from the end of the Santa Cruz Municipal Wharf, equipped this time with a 53-µm net used to collect phytoplankton. Phytos, as we refer to them, are the (mostly) unicellular photosynthetic organisms that make up the bottom of the pelagic trophic web. In a nutshell, they are the food that sustains all other organisms in the pelagic realm; i.e., every creature that lives away from the sea floor. Without phytoplankton, we would essentially have zero life in the sea. Think about that the next time you see a "Save the Whales" sign:  To save the whales, maybe we should work harder at saving the phytoplankton.

The water is still that pretty shade of aquamarine, but to the naked eye it seemed a little less opaque than it was a week ago. One thing I did see immediately was a huge school of bait fish, and a gaggle of teenage boys trying to catch them with their fishing poles. The school was pretty impressive; the teenage boys, not so much. But they get props for trying.

School of bait fish on the east side of the Santa Cruz Municipal Wharf, 24 July 2015. © Allison J. Gong
School of bait fish on the east side of the Santa Cruz Municipal Wharf, 24 July 2015.
© Allison J. Gong

I find schooling behavior fascinating. I love how the amorphous blob moves through the water, avoiding predators and obstacles (including my plankton net) alike with apparently little effort. Even the sea lions swimming around the pilings didn't generate much of a response from the fish except a lazy move out of the way.

The arrival of bait fish makes me wonder if whales will follow.


Back in the lab I looked at what I had caught. As expected there were very few large animals, but quite a lot of interesting phytoplankters and small zooplankters. Here's a sort of representative sample:

Marine phytoplankton collected from Santa Cruz Municipal Wharf, 24 July 2015. Key:  (a) Radiolarian, a type of amoeba; (b) Protoperidinium, a dinoflagellate; (c) Ceratium, a dinoflagellate; (d) unidentified golden cells. © Allison J. Gong
Marine phytoplankton collected from Santa Cruz Municipal Wharf, 24 July 2015.
Key: (a) radiolarian, a type of amoeba; (b) Protoperidinium, a dinoflagellate; (c) Ceratium, a dinoflagellate; (d) unidentified golden cells.
© Allison J. Gong

The coolest thing I found in today's sample was a silicoflagellate. I think in all my years of observing local marine plankton I've seen silicoflagellates only once before today, when I was in graduate school. Not much is known about their biology, but their siliceous fossils have been pretty well studied.

Silicoflagellate in plankton sample collected from Santa Cruz Municipal Wharf, 24 July 2015. © Allison J. Gong
Silicoflagellate in plankton sample collected from Santa Cruz Municipal Wharf, 24 July 2015.
© Allison J. Gong

Silicoflagellates are flat unicellular phytoplankters with two flagella that they use to swim. You can sort of see one flagellum sticking out at about 10:30 on the cell perimeter. You can see it better in this video clip (apologies for the background music). Watch as the flagellum wiggles and pushes the cell around.

Did you see the flagellum? How cool is that? Pretty fancy for a simple unicell, isn't it?

1

I'm sorry. I had to go there. You didn't really expect me not to, did you?

The reason, of course, is that today we got our first settled and metamorphosed Pisaster stars! We were doing our normal Monday water change when I noticed a teensy orange speck on the bottom of one of the jars. I used my beat-up old paintbrush to remove the tiny dot to a dish, put it under the dissecting scope, and saw this:

Metamorphosing ochre star (Pisaster ochraceus), age 48 days. 20 July 2015. © Allison J. Gong
Metamorphosing ochre star (Pisaster ochraceus), age 48 days. 20 July 2015.
© Allison J. Gong

From this picture it's a little hard to see what's going on. The entire body has contracted a lot, from a 2.5-mm larva to about 1/4 of the original size as a 600-µm juvenile, and become much more opaque. There are tube feet and spines as well as some remnants of larval body (the soft bits at the bottom of the animal) at this in-between larvenile stage.

Here's a picture of a fully metamorphosed little star:

Newly metamorphosed ochre star (Pisaster ochraceus), age 48 days. 20 July 2015. © Allison J. Gong
Newly metamorphosed ochre star (Pisaster ochraceus), age 48 days. 20 July 2015.
© Allison J. Gong

I expect we'll be seeing more tiny orange dots on the bottoms and sides of the jars in the next several weeks. At some point we will have to figure out what they eat and provide it for them. But at least we know we're able to get them through the larval phase.

Just for kicks, here are some pictures of where we grow the larvae and how we do the twice-weekly water changes.

Larval culturing paddle table. © Allison J. Gong
Larval culturing paddle table.
© Allison J. Gong
Step 1:  We pour the larvae into a filter to concentrate them into a smaller volume of water. Then we can wash or rinse the jar. © Allison J. Gong
Step 1: We pour the larvae into a filter to concentrate them into a smaller volume of water. Then we can wash or rinse the jar.
© Allison J. Gong
Steps 2 and 3:  We use a turkey baster to transfer most of the larvae from the filter into a jar of clean water. The final step is to turn the filter over and wash the last larvae into the jar. © Allison J. Gong
Steps 2 and 3: We use a turkey baster to transfer most of the larvae from the filter into a jar of clean water. The final step is to turn the filter over and wash the last larvae into the jar. Then we fill up the jar and resume the stirring.
© Allison J. Gong

An update on other matters:

Today is the six-month birthday of my baby urchins! Six months ago to the day these little guys were zygotes, and six-months-plus-one-day ago their parents were roaming the intertidal. They grow up so fast!

Juvenile sea urchin (Strongylocentrotus purpuratus), age 6 months. 20 July 2015. © Allison J. Gong
Juvenile sea urchin (Strongylocentrotus purpuratus), age 6 months. 20 July 2015.
© Allison J. Gong

And lastly, that little shmoo-type thing that I found in the plankton yesterday has revealed itself to be. . . an anemone!

One of the things I like best about cnidarians is the beautiful transparency of their bodies. I love how you can see fluid circulating through the tentacles. Gorgeous, isn't it?

California is being slammed by a very intense El Niño event, and the effects are being felt up and down the coast. Seawater temperatures here in Santa Cruz have been in the 15-16°C since late May, and in the past week have shot up to 18.5°C. While Californians have their fingers crossed that El Niño will bring drought-relieving rain this winter, I'm also concerned about how it is affecting marine life.

On a whim, I decided this morning to take a look at what's going on in the local marine plankton. I grabbed a plankton net with a mesh size of 165 µm (we call a net with this mesh size a "zooplankton net") and headed out to the end of the wharf. The water is a milky greenish aqua color, which the Monterey Bay Aquarium says is due to a bloom of a type of phytoplankton called coccolithophores. I've never seen living coccolithophores before, as they are usually not common in Monterey Bay. Besides, they are really small and don't often get caught in the type of plankton net that I deploy. So while I didn't really think I'd catch any coccolithophores, it is always fun looking at plankton. Given the warm water and lack of productive upwelling this season, I didn't know what to expect.

Water under the Santa Cruz Municipal Wharf, 19 July 2015. © Allison J. Gong
Water under the Santa Cruz Municipal Wharf, 19 July 2015.
© Allison J. Gong
Water on the west side of the Santa Cruz Municipal Wharf, 19 July 2015. © Allison J. Gong
Water on the west side of the Santa Cruz Municipal Wharf, 19 July 2015.
© Allison J. Gong

When the water around here is this color, it usually means that phytoplankton are not very abundant. And sure enough, when I pulled up the net it wasn't very brown and didn't have that certain smell of diatoms, which were extremely thick earlier in the season. In fact, earlier this month the Central and Northern California Ocean Observing System (CeNCOOS) detected high levels of both the toxin domoic acid and the diatom, Pseudo-nitzschia, that produces it. But in today's sample I didn't see a single diatom and only a few dinoflagellates. It's conditions like this--warm, nutrient-depleted water--that the coccolithophores like.

One of the best things about examining a plankton sample is that you never know what you'll find. Despite the lack of phytoplankton in the water, my sample was chock full of interesting zooplankters. In addition to the usual copepods (probably the most abundant animals in the world) and their larvae, there were larval polychaete worms and molluscs, medusae of multiple species, and assorted other goodies.

Goodies #1 and #2:

A metamorphosing sea urchin (left) and larval polychaete (right), collected from the plankton. 19 July 2015. © Allison J. Gong
A metamorphosing sea urchin (left) and larval polychaete (right), collected from the plankton. 19 July 2015.
© Allison J. Gong

In the video clip below you can see the familiar baby-urchin-learning-how-to-walk, as well as a better view of the polychaete. Note the conspicuous segmentation and chaetae (bristles) that the animal splays out when disturbed or, in this case, gently squashed under a cover slip.

The little worm looks like it's dancing! Sometimes you can see its four eyes.


Goodie #3:

Cyphonautes larva collected in plankton sample, 19 July 2015. © Allison J. Gong
Cyphonautes larva collected from the plankton. 19 July 2015.
© Allison J. Gong

This creature is called a cyphonautes larva. It is the sexually produced pelagic propagule of a benthic bryozoan colony, most likely Membranipora membranacea. If it looks like a swimming triangle, well, that's exactly what it is.


Goodie #4:

This living lava lamp is very enigmatic. I called it a shmoo-type thing and was so intrigued that I isolated it into a separate dish for further observation. I was delighted to see that, a few minutes later, it had settled and metamorphosed into this:

It has eight stubby little tentacles and an obvious cnidarian appearance. I think it is a little anemone, but only time will tell.


Goodie #5:

Radiolarian collected from the plankton. 19 July 2015. © Allison J. Gong
Radiolarian collected from the plankton. 19 July 2015.
© Allison J. Gong

This beautiful object is a radiolarian, a type of marine amoeba. The main part of the cell is concentrated towards the center and pseudopodia are extended along the skeletal spines, which, in addition to making the cell an unpleasant mouthful, also aid in buoyancy. This one was rather large, measuring about 2 mm across. I saw many of these in today's sample.

All in all I spent a very enjoyable morning collecting and looking at plankton. I didn't see any coccolithophores, but I'm thinking that I probably should go out again with a finer-meshed net to see if I can catch them. And to see what will happen with the zooplankton if the phytoplankton remain scarce for the rest of the season.

1

THE ANSWER TO YESTERDAY'S PUZZLE IS . . .

. . . drum roll, please . . .

Microcladia coulteri!

I showed you this:

Mystery red alga, 18 June 2015. © Allison J. Gong
Mystery red alga, 18 June 2015.
© Allison J. Gong

but what you really needed to be certain of the ID was the rest of the photo:

A mystery no more! Microcladia coulteri growing epiphytically on another red alga, 18 June 2015. © Allison J. Gong
A mystery no more! Microcladia coulteri growing epiphytically on another red alga, 18 June 2015.
© Allison J. Gong

Huzzah again for natural history! I love it when natural history provides the answer to a taxonomic or identification question. Sometimes you need to see the organism where it lives in order to understand what it's all about. Quite a lot of modern biology has to do with grinding up organisms and examining their DNA; while I do appreciate the evolutionary and ecological insights these data provide, it's really not my cup of tea. I'd rather spend my time looking at intact organisms than their molecules, and getting outdoors to see them in nature instead of running gels and staring at computer algorithms. As in most other walks of life, it takes many kinds of work to get at the whole picture in ecology, and I am grateful to be able to contribute a little piece to the puzzle.

9

If you visit the California rocky intertidal in the spring or summer, one of the first things you notice will be the macroalgae, or seaweeds. They are incredibly abundant and diverse this time of year, covering just about every bit of rock. In fact, in a landscape sense the only visible organisms are macroalgae and surfgrass:

Algae-covered rocks at Pistachio Beach, 18 June 2015. © Allison J Gong
Algae-covered rocks at Pistachio Beach, 18 June 2015.
© Allison J Gong

Of the three major divisions of algae (the greens, browns, and reds), the red algae are the most diverse. We have several hundred species along the California coast, and while they don't get as big as the kelps (which are brown algae) they display an astonishing assortment of morphologies, colors, and life history complexities. Almost all of the algae in the photo above are reds. The olive-greenish stuff? Yep, those are reds; multiple genera of reds, in fact. The dark brown things? Those are also reds, again representing more than one genus.

Within the incredible diversity of red algae, today I want to focus on two species: Microcladia coulteri and Plocamium pacificum. Both of these algae have delicate branching forms that make beautiful pressings. But despite their apparently similar morphologies, they represent different taxonomic orders and have completely different lifestyles. Let's take a look at how similar they actually are:

Two unrelated but morphologically similar red algae, 18 June 2015. © Allison J. Gong
Two taxonomically unrelated but morphologically similar red algae, 18 June 2015.
© Allison J. Gong

Pretty tough to distinguish, aren't they? The specimen on the left is a bit more robust in comparison, but if you had only one of these in front of you and nothing to compare it to you'd probably be hard-pressed to determine which species it is.

This is where an understanding of natural history becomes invaluable. Since these species are morphologically so similar to each other, an extremely helpful piece of information is where (and how) each one lives. In terms of habitat, these species can be found pretty much right next to each other, so that doesn't help much. However, the surface on which each species grows tells you exactly what you need to know.

The specimen on the left in the photo above is Plocamium pacificum, a member of the taxonomic order Plocamiales. It lives from the mid-low intertidal to the shallow subtidal and is always attached to rocks, as you can see below:

Plocamium pacificum at Davenport Landing, 17 June 2015. © Allison J. Gong
Plocamium pacificum at Davenport Landing, 17 June 2015.
© Allison J. Gong

The specimen on the left was taken from a thallus that was growing on a rock. This means that it is Plocamium pacificum. Now we can label our photograph with one name.

Plocamium pacificum (left) and a mystery look-alike (right), 18 June 2015. © Allison J. Gong
Plocamium pacificum (left) and a mystery look-alike (right), 18 June 2015.
© Allison J. Gong

The specimen on the right was growing as an epiphyte ("on plant") on a large blade of another red alga. This epiphytic lifestyle tells me that it is not Plocamium, but a species in the genus Microcladia in the taxonomic order Ceramiales. When I brought it into the lab to key it out I was able to identify it as Microcladia coulteri. Three cheers for natural history!

Here's a picture of M. coulteri growing on blades of another red alga, Mazzaella sp. See how green the Mazzaella looks? Color isn't the only factor that determines which major group an alga belongs to, and can in fact be quite deceiving!

Microcladia coulteri growing epiphytically on Mazzaella sp. 18 June 2015. © Allison J. Gong
Microcladia coulteri growing epiphytically on Mazzaella sp. at Pistachio Beach, 18 June 2015.
© Allison J. Gong

Finally, we have both specimens identified:

Plocamium pacificum (left) and Microcladia coulteri (right), 18 June 2015. © Allison J. Gong
Plocamium pacificum (left) and Microcladia coulteri (right), 18 June 2015.
© Allison J. Gong

Which is all well and good when you have two specimens in hand that you can compare directly to each other. But what if all you have is this little bit?

Mystery red alga, 18 June 2015. © Allison J. Gong
Mystery red alga, 18 June 2015.
© Allison J. Gong

Would you say this is Plocamium, or Microcladia? What would you base your decision on? And how certain would you be?

Submit answers (with justifications!) in the Comments, and I'll give you the answer tomorrow.

Today I decided to look at some scuzz growing in one of the seawater tables at the marine lab. This table is populated mostly by coralline rocks, although I have some pet chitons running around in it.

Coralline rocks in seawater table at Long Marine Lab, 16 June 2015. © Allison J. Gong
Coralline rocks in seawater table at Long Marine Lab, 16 June 2015.
© Allison J. Gong

I picked out a promising rock and examined it under some decent light. Most of the rocks have at least some fuzzy red filamentous algae growing on them; this one also had a bit of a filamentous green, which made it a promising subject for photography. I already knew what the green was (Bryopsis corticulans) but didn't recognize the filamentous red. The Bryopsis is in the lower right corner of the rock in the photo below:

Coralline rock bearing red and green filamentous algae, 16 June 2015. © Allison J. Gong
Coralline rock bearing red and green filamentous algae, 16 June 2015.
© Allison J. Gong

What was noticeable about the Bryopsis and the mystery red is the difference in size. Bryopsis looks positively dainty until you compare it with the red. Wanting to take a closer look at the red, I plucked off a bit and mounted it on a microscope slide. This is really the only way to see what's going on with these filamentous algae, and it works like a charm. You don't have to make a cross-section or anything; you just put the piece in a drop of water, add a cover slip, and look at what you can get:

Apical tip of Antithamnion defectum, 16 June 2015. © Allison J. Gong
Apical tip of Antithamnion defectum, 16 June 2015.
© Allison J. Gong

What first caught my eye was the rather simple branching pattern. The central axis is made up of roughly rectangular cells, each of which has two side branches that are opposite each other. Each of the side branches has branchlets on only the upper surface. Branching like this is relatively easy to draw (things spiralling around in three dimensions are really difficult for me), although my drawing isn't nearly as pretty as the real thing.

This microscope view, along with my little sketches, provided me with enough information to key out this alga even though it didn't have any reproductive structures. According to the dichotomous keys in Marine Algae of California* (the book that marine biologists refer to as the MAC, our Bible for identifying the algae) it is Antithamnion defectum. The MAC says that this species is common on other algae and can be found both intertidally and subtidally from southern British Columbia to Baja California. It could very well be that I see this species in the field, but these filamentous reds look pretty much the same, at least to my inexpert eye. It really does take a microscope to figure out what I'm looking at.


*Abbott, Isabella A. and George J. Hollenberg. Marine Algae of California. Stanford: Stanford University Press, 1976. Print.

Part of what makes the marine algae so fascinating to me is their life cycles. I'm intrigued by organisms that do things differently from us. And to be honest, from the perspective of someone who studies invertebrates and their life cycles, we humans are rather boring: we're born into in one body, reproduce (maybe), and then die, all in the same body. Ulva, on the other hand, follows the typical plant example and has a life cycle that includes alternation of generations.

Without going into too much detail, let's just say that Ulva has two generations within a single life cycle, one called a sporophyte and the other called a gametophyte. The difference between the sporophyte and gametophyte is the number of chromosome sets found in the cells of the respective generations: sporophytes have two sets of chromosomes per cell, a condition which we describe as being diploid (2n), while gametophytes are haploid (1n) and have only one set of chromosomes per cell. The diagram below lays it out nicely. Note that the gametophyte in the diagram is white, while the sporophyte is green.

Alternation_of_generations_simpler.svgThe little white circles in the diagram above are the reproductive cells. These cells are produced by either the gametophyte (in the case of gametes) or the sporophyte (in the case of spores).

Now, determining if what you're looking at is a sporophyte or gametophyte can be easy or difficult, depending on whether your species is isomorphic ('same form') or heteromorphic ('other' or 'different form'). Unfortunately for us, Ulva happens to be isomorphic, which means that the sporophyte and gametophyte are for the most part morphologically indistinguishable. However, if you knew what kind of reproductive cells a particular generation produces, you could deduce whether that generation is a sporophyte or a gametophyte, right? So, is there any way to determine whether a 2.5 µm cell is a spore or a gamete?

Yes, there is! In the group of algae that includes Ulva the spores are quadriflagellate, which is just a fancy way of saying that each one bears four flagella. The gametes are biflagellate, having (you guessed it) two flagella. Now it's just a matter of counting flagella on these tiny reproductive cells released by the specimen of Ulva in my bowl.

And voilà!

Biflagellated gametes of Ulva sp., 11 June 2015. © Allison J. Gong
Biflagellated gametes of Ulva sp., 11 June 2015.
© Allison J. Gong

It's clear that these cells have only two flagella, right? This means that they are gametes, not spores, and the thallus that produced them was the gametophyte!

Pretty dang nifty, isn't it?

I was making my last run through the wet lab today, about to head off to forage for lunch before a meeting elsewhere, when I saw this in one of my bowls:

Specimen of Ulva sp. spawning, 11 June 2015. © Allison J. Gong
Specimen of Ulva sp. spawning, 11 June 2015.
© Allison J. Gong

This is one of my feeding treatments for the juvenile urchins. The sheet of green stuff is Ulva sp., a green alga several species of which grow locally in the intertidal. You also see it in harbors and estuaries. This particular bit was growing ferally in one of the large outdoor tanks in an area of the marine lab called the tank farm.

You can see that the algal body (called a thallus) has a fairly distinct edge, except for the parts that the urchins have munched through. Can you also see the cloudy pale green water that runs sort of horizontally across the middle third of the bowl? That's the stuff that caught my eye. After glancing at the clock I figured I had just enough time to take a quick peek under the scope, and if I really didn't care about eating lunch I could even snap a few pictures and still make it to my meeting on time. Anyone who knows me personally understands that I organize my life around food and the next time I get to eat. The fact that I was willing to forego lunch to look at this green spooge should tell you how exciting this was.

(It turns out that a few minutes later the person I was supposed to meet with e-mailed me and asked to postpone our meeting until next week. Yes! This means actual quality time with the microscope and the spooge.)

Here's what a spawning green alga looks like:

That undulating column on the left side is a stream of reproductive cells being released by the thallus. And yes, those are my little urchins chowing down. They like eating Ulva much better than the coralline rocks they'd been subsisting on until recently.

Under the compound scope at 400X magnification, the reproductive cells look like this:

The tiny little cells zooming around are about 2.5 µm long. The way they swim suggests that they have flagella. Do they look familiar?

They should. They look a lot your typical flagellated animal sperms! I don't think it's a coincidence that my first thought upon seeing the green stuff in the bowl was "Spooge!"

But here's where it gets tricky. For algae, looking and acting like sperm doesn't mean that something is sperm. More on that in the next post.

I've been fielding questions about my recent sea star spawning work from people I've shared this blog with, which is a lot of fun! To streamline things and make the info available to anybody who might be following, I decided to put together a very brief FAQ-like post to address the most recent questions.

Question:  Can you watch the eggs divide in real time?

In a time-lapse sense you can watch cleavage divisions occur, but not in real time. What I can do is set up a slide on the microscope and leave it there for a while. The gradually warming temperature speeds up development to the point that I can sort of see the division in real time. Of course, the danger is that the embryo will cook on the slide. I generally figure that once I've pipetted some embryos onto a slide and dropped a cover slip on top of them, they're goners (it's not really possible to remove the cover slip without damaging the cells underneath it) so I feel marginally less bad about sacrificing a few to the gods of observation.

Questions:  I’m fairly certain that the stars can go back to the sea, but are you able to keep their eggs with them, too? How difficult is that transport?

Actually, my scientific collecting permit specifically states that I'm not allowed to return animals to the wild. If I needed to, I could apply for additional permits but it has never been necessary for the work I do. Surplus eggs and larvae, therefore, are discharged into the seawater outflow at the lab and do return to the ocean but the parents remain in my care.

Question:  Are orange and purple stars usually able to cross with each other?

As far as anyone has been able to determine, the color of stars has zero effect on whether two individuals' gametes are able to do the nasty together. The sea stars that I'm working with--Pisaster ochraceus, the ochre star--are broadcast spawners, meaning that each individual spews his/her gametes into the water, where fertilization and development occur. The stars are also synchronous spawners, meaning that if one individual in an area begins spawning other stars in the immediate vicinity will also spawn. After all, it does take two to tango, and to spawn while nobody else does is a tremendous waste of energy.

So yes, a purple star and an orange star should be able to mate without any problems... at least not any problems due to the parents' colors.

Question:  If so, what color do they end up being, statstically?

This is a very interesting question. Two of my colleagues are going to spawn Patiria miniata (bat stars) next week to address this. Their plans are to cross a Blue female with an Orange male, an Orange female with a Blue male, and both pure-color matings. They did a preliminary version of this experiment a couple of years ago but didn't end up with enough juveniles at a size that color could be ascertained; thus they couldn't calculate any statistically meaningful color ratios.

Questions:  Do you suppose that the wasting disease could be now in the genetic makeup? Any thoughts (unofficial of course) about this?

My thought is sort of the opposite, actually. The animals that we brought in from the field are all survivors of SSWS; if anything, I'd expect them to be resistant to whatever causes the plague, and to (hopefully) pass on this resistance to their offspring. Of course, there's no way of knowing if and how exposure to SSWS affects the quality of the gametes. It's quite possible that these survivors are less fit after the SSWS outbreak than they were before.

Question:  Purple Male with Purple Female developed well and purple Male with Orange female didn’t…some sort of incompatibility?

Well, given what I saw today the Orange (female) x Purple (male) cross almost certainly did not work. Fertilization occurred, but almost none of the embryos had any indication of normal development. Since we know the Purple male was able to mate successfully with the Purple female, we can infer that his sperm were fine. It could be that there was something going on with the Orange female's eggs; there were a lot of them, but maybe their quality just wasn't very good. Or perhaps we somehow mistreated and wrecked them the other day.

Any other questions? Use the Comments section to ask them, and I'll address them in a future post.

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