Showing posts with label urchin. Show all posts
Showing posts with label urchin. Show all posts

Monday, March 6, 2017

Highlights from the recent NOAA Okeanos Explorer Samoa Expedition!

So, here is a nice highlight of various wonderful invertebrates observed by NOAA's deep-sea research vessel, the Okeanos Explorer which for all of 2016 and 2017 will be studying the massive marine reserves of American territory in the tropical Pacific!

DON'T FORGET OKEANOS LIVE FEED RESUMES MARCH 7!
From now until April, they have been in American Samoa! You can see an overview of their expedition here. But if you have been following along, then you've been enjoying about 2 weeks of deep-sea research streamed LIVE here: http://oceanexplorer.noaa.gov/okeanos/media/exstream/exstream.html


But obviously, not everyone can watch EVERY day during the entire dive. So I present some cool highlights (but invertebrates) from the last leg of the research dive.  

My thanks to Santiago Herrera and Matthew Jackson the biology & geology science leads for this last epxpedition!!

If you have missed it and are interested you can always go to Twitter and search for #Okeanos often with #Samoa or other similar terms.

You can also go look at screengrabs on the Facebook group

Also a reminder based on recent news about significant budget cuts to NOAA Remember that NOAA operates the Okeanos Explorer program!!  The oceans represent a HUGE unknown quantity and yet, we have no exploration arm to explore the amazing deeps of the Earth. Deep-sea News has made a GREAT argument about why we need an "Ocean NASA"! And right now, the closest thing NOAA gives us the closest thing to that! 

So, if you enjoy these and other images as well as the livestream RESEARCH and DISCOVERY please contact your congressional representative and LET THEM KNOW: DO NOT DEFUND NOAA.

and now.. onto some cool beasts!!


PROTISTS! 
Most of what I'll present here are animals, but in the deep regions of the ocean, single-celled organisms that are basically HUGE amoebas can develop fairly LARGE structures out of sediment. I've written about them here. Some are called xenophyophores but it turns out that there's a fair diversity of them.

 Here's at least one structure observed on Utu Seamount at about 3030 meters! 


SPONGES!! Some of the most commonly encountered animals on these Okeanos dives are sponges. Sponges are relatively simple animals that are basically big masses of cells but some of them use specific kinds of materials to create skeletons.  Some use calcium carbonate, some use a fiber called spongin..and one group which is seen commonly in the deep-sea: glass or silicon dioxide.

I've written posts about glass sponges before, here and a prior Okeanos cruise discovered what is probably the largest glass sponge known here. 

Here's a large one with a thick stalk and a large opening on the "head"
This is a cool one: this is a cladorhizid sponge. Many cladorhizid sponges are predatory and I think this one is as well..

those spines emerging off the edge makes it a deadly deep-sea umbrella!
Here's another one from a different angel from Rose Atoll, about 2525 meters! 

This is a glass sponge in the Euplectellidae, which is often identifiable by the unusual "cap" on the top of the sponge.. These are known for having 2 commensal male and female mated shrimps which do not escape from the internal cavity.. 
I missed the name/identification on this one..but I like to point out that those brown "roots" are actually GLASS. Glass sponges often seem to be growing "living" fiber optic cable and have been studied for their optical properties! 

WEIRD CNIDARIANS!!
Cnidarians are of course-those animals with stinging cells and radial symmetry. Jellyfish, sea anemones, hydras, hydroids and so on.They account for a huge diversity in deep-sea habitats! 

 This "cosmic jellyfish" has been making the rounds. Its been identified as Benthocodon hyalinus by my colleague Allen Collins at NMFS. It was observed on Utu Seamount at about 3006 meters!! 



Its not unusual for us to see a giant hydroid on these dives.. This one identified tentatively as Corymopha


One of the most noteworthy of the cnidarians observed was this Dandelion or benthic siphonophore. Siphonophores are colonial animals which are mostly found swimming though the ocean in long chains which in some instances can be meters long!  Familiar species include the painful Portuguese Man o War. 

BUT the species in this group live attached to the bottom, apparently with a huge array of feeding tentacles extended.. there's a blog about these waiting to be written! hopefully soon...
Similar in lifestyle-check out this tiny bottom living (aka benthic) ctenophore (or comb jelly). I've discussed these at length before here. Again, most comb jellies swim-but then you get these oddballs that have an active bottom life using their long tentacles to capture prey.
A mushroom coral! Rose Atoll, 680 m


Probably the BIG, weird star of this leg was this BIZARRE blobby tree shaped thing! Turns out its a bizarre sea anemone in the family Aliciidae! Its tentacles had been withdrawn...
It turns out we saw one of these during the Marianas expedition LAST year!  Which makes the one above a likely DIFFERENT species from the other one we saw which had yellow buttons rather than white ones..

 Dr. Dave Pawson at the National Museum of Natural History was apparently stung by one of these (only 6 inches long) and reported that each of these buttons are batteries of STINGING cells which can cause painful stings that last for several hours!! (click here) 

MOLLUSKS! 
Unsurprisingly, some of the most exciting observations on this last cruise were MOLLUSKS! We don't normally see a lot of snails or clams on these cruises..but we made up for it on this dive! 

Neopilina, MONOPLACOPHORAN! 
Few animals that I know of have what might be considered "holy grail" status. THIS is one of them..

In this case, the mysterious mollusk known as Neopilina! This mysterious mollusk has previously been collected from abyssal and ultrabyssal depths between 4000 and 6000 meters. From both the Atlantic and the Pacific. 

These are rarely collected and in the past were perceived as being VERY important to evolutionary or other ecological studies.  Basically these animals were regarded as ancient AND ancestral mollusks-the "Ur mollusk" if you will. They inspired a LOT of questions about what they were related to and how other mollusks were related to one another.. 

But I think this might be the FIRST time an in situ (in place and ALIVE) observation has been made! I admit that this tiny brown limpet thing does not have the same... presence as say some giant octopus  or squid, but once you know all the history behind it.. well, I say this with no irony-seeing it alive in its habitat was HISTORIC!!


 Octopus!  So, of course we are always fond of cephalopods when they turn up! This white translucent octopus species was observed at least twice on the dive at relatively "shallow" depths between 380 and 400 m. This first shot was from Tau seamount.

 Note that the webs of skin between the arms were translucent! 
This one was seen at Rose Atoll at about 393 m and it was investigating a series of little holes and caves.. presumably looking for food..



ECHINODERMS!! So, where MY group is concerned I'm always a little biased and have more imagery than of other groups (not as many corals for example). And because I work on starfishes-there's enough pics that I will get to those in another post!

 but for now, here's some striking "spiny-skinned" friends that I saw...

 This funny beast which I think was in the Deimatidae? Note that as with many deep-sea sea cucumbers, the body wall was translucent and we can see the sediment eaten by the animal THROUGH the body wall! 
The bizarre semi-swimming sea cucumber Psychropotes I blogged about this genus of sea cucumber and the number of species there might in the world oceans! 
This sea cucumber (Paelopatides?) in free swim glide! Moki Seamount about 2083 m WHEEEE!

This interesting fold over backwards behavior of a sea cucumber at Utu Seamount

A sea urchin the family Pedinidae I think? Lovely greenish coloration!
A reddish.. echinothuriid urchin? Aka a "pancake" or "tam o shanter" urchin. I've written about these before  here.  We saw a few different species of these kinds of urchins. But they are difficult to ID from pictures..

MIXED TAXON CRAB + COMBINATION!!
There were at least two interesting cases where we saw crustaceans "team up" with another animal that one does not normally associate.....

1. Decorator crab + cidaroid urchin! This was an odd one. The ROV was observing this cidaroid urchin..and as it changed angles.. it noticed this majiid type "decorator" crab hanging on with its rear legs. We've seen other crabs hanging onto fire urchins in tropical shallow-water habitats as protection-but not seen something like this. Unclear if it is incidental or something that happens regularly...

2. Zoanthid "anemone" PLUS hermit crab! A relationship that has been seen before but no less weird whenever we see it. Basically a sea anemone-like animal called a zoanthid rides and replaces the shell that this hermit crab would normally be wearing..

The crab benefits from the protection and the zoanthid gets driven around by the crab for dispersion, food, etc.. Interesting commensalism!

Here's a nice one seen back in 2015 by Diva Amon!

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Wednesday, March 2, 2016

Echinoderms with Spines for Walkin'

OKEANOS Explorer is BACK!!! And even though they've only been able to venture into the field for two days, there's already some AWESOME video which inspires this week's post!! 

Sunday, the ROV spied this awesome beast, a weird sea urchin in the genus Aspidodiadema. Although there's at least one species known in this area, A. hawaiiensis, I'm not sure that this is the same thing.

I've talked about this urchin before.  The spines bow out from the central body and touch the bottom rather than simply projecting outward as they do in other species. They are unusual in that they use their spines to "walk" along the sea bottom.

Here's a diagram of another species but with the "walking tips" clearly deployed on the bottom


On Sunday, they spied ANOTHER Aspidodiadema sp. But the video actually captured the unusual TIPS of the walking spines!!!
Do you see those round, circular tips that are on the tips of the spines??

Look at the red arrows below pointing to the "walking cups" on the spines that the urchin uses to move!
What's also kind of interesting is that this animal (and I think a few others) were actually CLIMBING a rock face and not just walking along a flat surface as diagrammed by Mortensen back in the day. So, these do a lot more than just just support..

Think of the spines like the long legs on the spider robot from Johnny Quest!

The "walking tips" of the spines look sort of like little hooves that the spines use to gain purchase on the substrate probably in conjunction with the tube feet. The center illustration shows what the bottom of that "hoof" looks like as you look directly up into it.. basically a modified spine tip adapted to aid in movement!

So, we HAVE seen something like this before in  Echinothuriid or "tam o shanter" or "pancake" urchins! 

I've done this story more than a few times..with one of the most recent accounts here.

Long story short: The urchin walks on a bunch of little legs with modified tips that ALSO resemble hooves! 

Look for the little white tips on the spines around the bottom edge!! Those are how it moves around on the soft-muddy substrate.
Spiny sea urchin
Sea Urchin underbelly
Here's a close up of what those look like!!! Superficially similar to the ones in Aspidodiadema!  At least in shape..
But wait.. There's MORE????   How about in STARFISH???
That's right! I'm pretty sure I've found spines that might serve in a similar (or maybe opposite?) fashion in deep-sea sea stars!  The filter-feeding Brisingids!! (here)

I just published a paper last year which documents some work I did recently on Hawaiian brisingids!
The starfish actually live on old munitions and junky metal debris.. I wrote about it here

Among one of the discoveries was a new species of the brisingid genus Brisingenes in Hawaii! Scientific paper citation is here.
The species was named Brisingenes margoae in honor of Dr. Margo Edwards at the University of Hawaii! She is a professor of geophysics working on mapping this unusual munitions filled terrain! 

She was head of the project and invited my participation! 
After collecting these starfish I noted something rather interesting.. the tips of the spines that occur on along the tube foot grooves were stained brown from contact with the metal casings they were sitting on! 

The one on the right shows the brown tip on one spine..
 This suggested that these were actually inset or even anchored into the surface rather than just kind of pointing away as has been suggested from watching them filter feed..

But when you look further at some other species, you see that there's probably an additional way for them to remains stabilized on whatever bottom they happen to be sitting on..
Here's a close up of some of those spines in one species from the North Pacific.. The tips are kind of wide and hoof-like! Similar to what you see in Aspidodiadema and the echinothuriid urchins! 
The case for the functioning of these spines is still sort of at the "hypothesis" stage at the moment..but it seems like a good argument all things considered. It seems likely that they serve at least in part as anchors. But do they use them to move also? Little walking legs? Something in between? Do they vary depending on where they live?

This all makes sense though. Spines are how these animals interact with their environment. In these deep-sea habitats where you have a lot of water currents and unstable bottoms, these spines help them. Either as support or to help move efficiently where a soft tube foot might not.

Weird. But I love figuring out strange sh*t like this!!
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Friday, September 25, 2015

Know your Deep-Sea Urchins! (Okeanos echinoid edition!)


Leg 4 of the Hohonu Moana Okeanos Explorer Expedition has begun! (here is the link to live feed!)

We have new investigators Scott France (on invertebrates) and MacKenzie Gerringer (on fishes) studying the huge diversity of deep-sea corals, sponges and other life in the northern Hawaiian Islands region.

The Hawaiian region brings with it a very different fauna from the one we saw in the Atlantic Okeanos cruises. There's actually quite a bit more diversity in the Pacific in sea stars, and many other echinoderms. So I thought I would offer a guide to some of the more prominent groups of echinoderms that we are likely to encounter in these deep-sea habitats: the sea urchins!!

Most everyone is familiar with the spiny balls that one observes in the intertidal or while SCUBA diving. 
Burrowing Urchin, Echinometra mathaei
And basically, sea urchins in the deep appear the same.. BUT many of them are unusual in some way.  Different adaptations or different evolutionary histories and there's much more to them than the "typical" urchins most people encounter in shallower depths. 

Here are some of the more commonly encountered sea urchins we will likely encounter in the Hawaiian region (below about 1000 m). These are also pretty typical of deep-sea settings throughout the Indo-Pacific.

There ARE a few that aren't noted here. Mostly the "irregular" urchins such as sand dollars, or sea biscuits. 

My thanks in advance to the Facebook screengrab group and Carina M. Gsottbauer

1. Aspidodiadema:  This is a genus of unusual deep-sea urchins that is represented in Hawaii and in many tropical deep-sea habitats in the Pacific as well as one species in the Atlantic. These have really long spines that it uses for locomotion in conjunction with its tube feet.

There's apparently more than one species of Aspidodiadema in Hawaii, but so far we've been calling the one seen by Okeanos, Aspidodiadema hawaiiense. Upon looking at both images, there do seem to be some differences but its unclear without a specimen to examine..
Here's a nice moving GIF of this Aspidodiadema species on the move! 
This image shows the same type of animal as the one above but with a mysterious bag like extension emerging from the top. Possibly an anal sac as we see in diadematid urchins?? Unclear.
In comparing them, this second one seems to be lighter in color... 

2. Caenopedina! This genus is a member of the family Pedinidae, of which it is the only living member. This genus is widely occurring mostly in deep-sea habitats. 

According to the Hawaiian Undersea Research Lab's Animal ID guide, there are two recognized species in the region: 

Caenopedina pulchella This species shows these very thick spines which are brightly colored green and purple!
The small individual above seems to have much smaller spines relative to this larger one.. but the colors patterns appear consistent..

This second species is Caenopedina hawaiiensis and it seems to show a very different appearance... 
3. Echinothuriid Urchins! These are one of the most frequently encountered sea urchins in deep-sea settings. Commonly referred to as "pancake urchins" or "tam o shanter" urchins, their body shape is suspended by water pressure, so when removed from the ocean into say, a bucket on the deck of a ship, their very soft skeletons collapse into a flat "pancake" like shape.

I've written on these animals plenty of times here and here and their shallow-water relatives here. 

One caveat about this section: I'm not sure that any of these can be correctly identified..so I'm keeping it vague. At least for now. 

But salient features of the urchins as a group include: 
1. Needle sharp spines which can be pretty dang painful!
2. Cute little walking legs with special "hooves" on their spines 
We've seen at least 2 species.. this purple species..
Rewatching yesterday's #okeanos dive: sea #urchin w/ mittens on its spines #Hawaii, Lone Cone ~1800m pic.twitter.com/kEL4cTtBIn
There's this slightly different pink echinothuriid
 this grey species                            

Echinothuriids are a frequently encountered group in the deep-sea. We will likely encounter more of them..

4. Cidaroid Urchins! One of the other "typical" urchins one encounters in the deep-sea is that cidaroids.  This is a fairly old group of urchins, which branched off early in the history of urchins and has a fairly good Mesozoic fossil record (see here).   

Cidaroids are unusual for urchins in that they lack skin on their spines, which results in an overabundance of "fouling" animals which can settle and grow on them. I've briefly talked about the ecological importance of this here. 

We've also seen cidaroids with a CRAZY range of spine shapes and morphologies, such as what I summarized here. 
                           
Cidaroids are not just predators on corals as shown below, but are also likely predators on stalked and other crinoids as I've posted about previously..

A nice diversity of cidaroid urchins in the deep-sea Hawaiian Islands.. More at the HURL gallery here.   but sadly we've really only seen a few at the deep depths Okeanos has been exploring..

Histocidaris variabilis.. note the barnacles growing on the spines...


 Stereocidaris hawaiiensis

Possibly Stylocidaris calacantha.  This one was observed high up in the branches of this bamboo coral, likely feeding on the polyps..

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