Tuesday, July 27, 2010

Starfish from Deep-Sea Hawaii- What Lives Below A Tropical Paradise!

So, this week...a special TREAT! A recent visit by a colleague from the Hawai'i Undersea Research Laboratory (HURL) at the University of Hawai'i at Manoa has resulted in my being able to show all of my loyal Echinoblog fans some EXCLUSIVE images of the deep-sea fauna in the Hawaiian Islands!!

Hawai'i has some AWESOME shallow-water echinoderms. I've blogged about many of these species.

This includes such cool critters as Colobocentrotus-the shingle urchin and some uncommon/rarely seen starfish, such as Coscinasterias, Valvaster, and Astropecten. As well as some neat artistic renditions...

Most people don't realize that HURL one of the most active deep-sea laboratories in the United States with ongoing research in marine biology, oceanography, geology, and even anthropology (discovering World War II submarines and shipwrecks for instance!)

They operate not one but TWO manned submersibles in American waters-the Pisces IV and the Pisces V. Plus a remotely operated vehicle.

Both subs are deployed off the mother ship, the Ka‘imikai-o-Kanaloa (often abbreviated KoK) which is Hawaiian for "Heavenly Searcher of the Sea" Here is the Pisces V being deployed from the aft deck of the KoK.

...and thanks to Craig Young, I've actually been down in the Pisces V (in 2001) and found it to be one of the coolest things I've ever done!

I've had a fairly LONG association with not only the Hawaiian Undersea Research Lab, but also the Invertebrate Zoology department at the Bishop Museum in Honolulu, Hawaii, where I helped identify and sort the echinoderms in the collection.

I was ultimately able to learn and help to identify the deep-sea starfish/sea star fauna in and around the Hawaiian Islands.

Its interesting that there's actually a much HIGHER diversity of deep-sea starfish around Hawai'i then shallow-water. But sadly, much of it is very poorly known. We continue to discover new things about the invertebrate fauna around the Hawaiian Islands on a regular basis!

Thanks to HURL..I am now able to share the diversity of (at least some of) this fauna with you!

What follows are images taken by the Hawaiian Undersea Research Laboratory of the animals in their habitat. (sorry for the bars at the top-these designate the species, dive and locality...)

Bear in mind...there are NO common names. Why? Because almost NO one other then scientists and possibly the occasional deep-sea fisherman, who gets one caught in a net gets to see these!

1. Anseropoda insignis. A weird deep-sea species found throughout the Indo-Pacific, but ONLY in deep-water (This one from 200-300 m or so..) The body is FLATTENED and almost PAPER-THIN. And are easily damaged when collected by trawl nets...so you almost never see them alive like this....

These are decent sized, about 8 to 10 inches across.

2. Tremaster mirabilis.
I blogged about this as a species, "about which, little is known.."

but here..we see it sitting practically FLUSH on the sea bottom.. About 4-6 inches in diameter.

3. Astropecten polyacanthus.
I just thought it would be interesting to show that even shallow-water species can get quite deep. This one was from less then 100 m (I'll have to check exactly how deep). Here is a post I did about one found in shallow-water.

4. Pentaceraster cumingi. At one time, this species was more commonly encountered at SCUBA depth, but I have anecdotally heard that because of its large size lack of abundance, and slow movement, this species has been rendered "locally extinct" in some places because people take them. But still occur in fairly deep-water (50-130 m)...

These are big..almost a foot and a half across..as are most oreasterids.

5. Asterodiscides tuberculosus.
This is a species that you can see at the deeper end of a SCUBA dive. There are two toenail-like plates at the end of each arm. We know almost nothing about it.

Decent sized animals..about 6 to 8 inches across.

4. Ctenophoraster hawaiiensis.
This species was described by Walter K. Fisher in 1906. We know nothing about it. This species is about 7 to 9 inches across.

Tamaria triseriata. Another species that is really pretty..but whose biology is unknown.
About 5 to 6 inches across.

Calliderma spectabilis (which is a synonym of Calliderma emma).
These are amazing to see on video. They get BIG..and are almost a foot and a half across (armtip to armtip)! Probably because of their size, these are collected quite frequently.

It is interesting to note that the genus Calliderma also occurs in the Cretaceous of Europe, which suggests that this may be one of those critters that has been around and unchanged for quite a long time...

7. Calliaster pedicellaris.
This is a pretty handsome animal. Sharp, cone-shaped spines cover the edge and the surface. We know pretty much nothing about it other then that.

Good sized about 6-7 inches across.

Coronaster eclipes.
Another BEAST of a starfish! These can be VERY big..almost a foot and a half across. Possibly a predator? Described by Walter K. Fisher in 1925 and until the submersibles began operation...rarely encountered since then...

9. Brisinga panopla
What's a bunch of deep-sea pictures without a brisingid or three?
There are actually about four species of brisingid that are known in and around the Hawaiian Islands..

What are brisingids? Short answer: starfish/sea stars that are deep-sea filter feeder/predators. Go here to read more! plus, they have Cool names. (go see!)

These can get to be over a foot in diameter.
So, this is NOT all of the species...just the ones I thought were immediately interesting. There's a LOT more. How many more?? Go check out this checklist for the starfish I helped develop..
and here's the master list for all Hawaiian Invertebrates..

Hopefully...I'll get to show some other species at some point...

Interested in more Hawaiian Invertebrates??

Here's a GREAT book-"In Deeper Waters" by two of the primary scientists at HURL available at Amazon..
and here is John Hoover's excellent field guide to shallow water (with some overlapping into the deep-sea) invertebrates!

Tuesday, July 20, 2010

Another Worry From Global Warming: Parasites that EAT Starfish SPERM!!!

This week, we have what sounds like a horrific title: Starfish Sperm Eating Parasites!

Parasites are weird and freaky...and how many people out there knew that Sea Stars even HAD parasites???

yes! they do. So, let's get to it!
1. The Parasite- and....it does WHAT???
So, in the early 2000s, Bill Stickle, a marine biologist at Louisiana State University authored several studies looking at the parasitic relationship between a ciliated protozoan Orchitophrya stellarum (described way back in 1907) and several different sea stars from the North Pacific.

in a series of papers published by his lab, including this one (2005), this one (2007) and this one (2001) (this wasn't all of them) , they describe the close relationship this parasite has with its host(s).

2. Orchitophrya LIVES AMONG and EATS starfish Sperm! Yes that's right! These little single-celled animals probably enter through the gonopores (although there's lots of big spaces for a tiny critter to enter on a starfish) and invade the gonads/testes of male sea stars (location indicated below with red arrows) and get right to work eating up all of their little starfish baby-makers!

Interestingly, the parasites do NOT attack the ovaries (female reproductive structures).

Apparently, these parasites were FILLED with phagosomes (digestive bodies) which included numerous sperm in various stages of digestion.

Here is a pic of one of these guys right in the middle of a spermalicious FEAST!

This has some MAJOR impact on the amount of sperm produced by the host species, which are particularly ripe in brooding winter males and spring-summer broadcasting males (i.e., when they are ejecting sperm into the water and females are ejecting eggs into the water at the same time).

But WHAT species? Well, apparently, these parasites like asteriids..which are very familiar beasts such as (this is an incomplete list)

Pisaster ochraceus
Leptasterias spp.
and...the North Pacific Asterias amurensis (now invasive in Australia). Early studies on the interaction between the parasite and their hosts were actually performed on this species...
The Atlantic Asterias forbesi, was actually one of the first species discovered to host the parasite-from populations in Europe and the east coast of North America, which may be where it originated. But its unclear how/where this happened..

3. Orchitophrya is a KICK-ASS Starfish sperm-eating Parasite! (but can live life on its own)

Stickle's lab discovered that the parasites CAN actually live outside and away from sea stars, but they become smaller, they become less developed and their mouth actually moves away from the front of their body!!

Now, when you FEED them asteriid starfish sperm? ALL of these changes REVERSE themselves!! So, Orchitophrya is considered a "facultative" parasite...that is it can live free of the host when it needs to do so.

The range of the parasite seems to have gotten as far south as Washington but based on several of the surveys taken there were only a few regions that had unusually low sperm outputs from parasitized male adults.

3. When it gets (global warming) HOT, the parasites get BUSY.
There has been much concern over what will happen to various marine invertebrates as global warming intensifies. And there has been some concern about how, even our local faunas, such as the Ochre Stars will be affected.

A new paper by Amanda Bates, Bill Stickle and Christopher Harley in the Journal of Experimental Marine Biology and Ecology uses some lab results to postulate what might happen to Orchitophrya under higher temperature conditions...

The authors isolated the parasite and cultured it. Then exposed it to Pisaster ochraceus
and Patiria miniata
at variable temperatures-the control versus 10 and 15 degrees C.

Interestingly, the parasite much prefers Pisaster to Patiria, which further details how specific the relationship is...Orchitophyra likes asteriids (e.g., Pisaster, Evasterias, and Asterias)

Higher temperatures led not only to increased DENSITY of parasites but also infection INTENSITY.. That is, greater amounts of the male testes were infected.

The end result?

After 21 days, so much of the sperm in the testes has been consumed that effectively, the hosts have partly to completely lost their "reproductive potential". That's effectively castration (emasculation?). Yikes!

So, what does that mean?

As all good scientists do, the authors warn that lab results don't always translate directly into what you see out in the "wild". There's a lot of variation in temperature of local areas and of course, the various populations and so on.. and more work needs to be done..

HOWEVER, they do note an interesting case of temperature increase of 1.5 degrees C per decade from 1976 to 1997 in Tokyo Bay. The temperature increase corresponded to the first detection of the parasite in Tokyo Bay in 1996! So, maybe some cause for concern is here?
This is a great example of how global warming's effect could conceivably extend beyond simply the direct effects on marine faunas. Who knows what weird combination of dominos could be altered?

In this case, the changes in water chemistry may benefit some asteroids (as indicated here), but on the other hand, SO will their parasites!

Speaking of unintended impacts, I can only wonder how many extra hits I will get from disappointed people who were looking for out of context key words in this blog's title... :-)

Friday, July 16, 2010

Pycnopodia Juvenile Stage Has Arrived!!

July 16 UPDATE!!! by Allison Gong:
What does Pycnopodia look like before it starts growing into an "adult"??? 

My colleague Dr. Allison Gong at the UC Santa Cruz Long Marine Laboratory recently had the fortune to observe the spawning and early larval development of Pycnopodia helianthoides-the sunflower star one of my favorite animals!
(This and all pictures courtesy of Allison Gong, UCSC)

Info and the comments below are graciously provided by her (seen above in her natural habitat)!

Apparently the gametes collected were produced by these hefty beasts on display at the Seymour Center. There are four in the aquarium. Each one may be either the mother or the father of these larvae.
(This and all pictures courtesy of Allison Gong, UCSC)

Allison says: "This is a 3-day-old early dipleurula larva. It is basically a ciliated blob with an invagination in the flattened posterior end. The internal tube and knob structures are the developing larval gut."

(This and all pictures courtesy of Allison Gong, UCSC)
Allison says: "This photo is essentially the same thing, photographed under dark-field conditions for a rather cool effect."
(This and all pictures courtesy of Allison Gong, UCSC)

A neat black and white shot...

(This and all pictures courtesy of Allison Gong, UCSC)
Two More!!
(This and all pictures courtesy of Allison Gong, UCSC)

UPDATE Ladies and Gentlemen, we have BIPINNARIA!!! (an intermediate larval stage of starfish)
Sez Allison: "These guys sure don't develop as quickly as urchins! At 14 days, the larva has reach a stage called the bipinnaria. It's sort of a more elaborate version of the dipleurula. In this ventral view, you can see the stomach quite clearly as the darkish ovoid shape in the bottom part."
"Here's a left-side view of a different larva at the same stage. These guys are really transparent, and it's hard to get a feel for their three-dimensional structure because the camera focuses on a single plane."
"These guys happened to swim under the objective lens at the same time, so I snapped a shot of them. In this photo you're getting both a ventral and a dorso-lateral view."

10 June 2009-Allison Sez: These larvae are growing so slowly! I'm used to things happening more quickly. Oh well. This is a ventral (front) view of a 22-day-old bipinnaria larva. The internal ovoid structure in the lower half is the stomach, with dark food cell visible inside. Here's a trick to "seeing" the 3-dimensional structure in a 2-d photo: Imagine a capital letter 'c' and rotate it 90 degrees along its vertical axis. You're now looking into the "opening" of the 'c', right? That's exactly the view of this larva. The roughly triangular object on the top and the squarish object on the bottom correspond to the ends of the 'c'. Confusing, isn't it?
Okay, here's a nice lateral view. The gut is nicely visible in this picture. You can see the elongated esophagus and the sphincter where it meets the stomach. You are looking at the larva's left side, with its anterior end up and its posterior end down.
Bipinnaria larvae reaches the 29 day stage!

Sez Allison: We had a near miss late last week and lost about half of the larvae. I think maybe they didn't like the food we were giving them. We've altered the diet and the remaining larvae seem happy, although some of them may be arrested at an early stage of development.

This individual was the most advanced of all the larvae I observed today. At 29 days it is starting to develop little nubbins that may grow into long brachiolar arms--at least, I hope they do!--and measures 850 microns in length.
Sez Allison: This larva, at the ripe old age of 49 days, has reached the brachiolaria stage. It measures a whopping 1.5 mm long! The gut is a golden color because we've been feeding them a mixture of green algae and diatoms.

The simple band in the earlier stages has been elaborated into pointy little nubbins called brachiolar arms. In other species, such as Pisaster ochraceus, the arms get really long; I don't know how long they'll get in these Pycnopodia larvae. We'll have to wait and see.

Sez Allison: Whoa. Huge progress made in the last week! The larvae are 55 days old now and have *finally* started growing the long arms we've been expecting for weeks. I shot this photo through my Wild dissecting scope to get the cool effect of a dark background. Couldn't entirely get rid of the unwanted glare, though. Oh well.Sez Allison: Here's a closer shot of the same larva. The brownish structure in the bottom of the larva is its stomach.
From Allison: Isn't this gorgeous? At 66 days (7 weeks and counting) the larvae have reached the advanced bracholaria stage. The arms are longer and the larvae wave them as they swim around. These guys are still feeding, although they haven't grown much. It looks like they max out at about 1.5 mm in length. This particular larva may not be entirely competent (i.e., ready to metamorphose) yet, but it's getting close.

From Allison: Ta-dah! One larva has begun the process of metamorphosis. It has attached itself to a small piece of mussel shell with some suckers on the anterior end. The round structure you see at the top of the animal is the juvenile rudiment, or the earliest stage of the juvenile body, containing the water vascular system's first 5 tube feet. You can see that the brachiolar arms are still there. At this point the critter can no longer feed, as it completely re-arranges its entire body, and survives on energy reserves it put away as a feeding larva.

I never get tired of watching this kind of metamorphosis, in stars or urchins. It's the coolest thing out there. In a matter of a few days the animal transforms from a bilateral swimming creature to a pentaradial crawling beast, with a full scale re-arrangement of its external and internal anatomy. Larval parts will be resorbed or discarded, and new juvenile structures will be formed.

Amazing, isn't it?From Allison: A star is born! The little guy we've been monitoring, seen here in side view, has completed metamorphosis, and as far as I can tell is doing fine. All of the larval body has been resorbed now, and the critter is a little round disc with tube feet and spines. It's not very active right now but I think that's because it's recovering from the trauma of metamorphosis.
From Allison: I tried to get a better view of the aboral (i.e., top) surface but immediately lost contrast because the baby star is almost the same color as the bit of mussel shell it's sitting on. At least in this view you can see that it's radial now. Quite a change from the bilateral larva it was a week ago, isn't it?

I think these new juveniles will fast for a number of weeks, living on energy reserves they packed away while they were feeding larvae. It remains to be seen whether or not we can figure out what to feed these tiny guys, but we'll try to keep them going and will hopefully be able to document how all of the arms develop. Remember, these stars have ~20 arms as adults, although they start out with the requisite echinoderm 5, and we're interested in seeing if there's a pattern to how all the arms form.
So, a late addendum... have you ever wondered what Pycnopodia looks like when they are just wee babies?? Here ya' go..According to Allison, this is what they look like 23 days past settlement. They have FIVE rays just like ANY other SEA STAR. Neat, eh??

From here, they grow onto the enormous, multi-rayed forms that we know and love! I suspect that takes AT LEAST several months to years.... so, leave em' alone when you find em as adults! It probably takes a LONG time for them to reach even a 6 inch diameter!