ROV Hercules Dive NA124 H1841 2020 10 30 20 50 33 473 UTC 4 W1

So we're about to start a 100 metre transect as we continue up the western side of San Juan Sima. And we keep the lasers on and try and keep a steady distance from the bottom. Our qualification is organisms that live here. And we try and do about five of these transects per dive. You can see potentially the change in the community structure as we go up the slope. We're heading into a lower oxygen region. It's sure to have an impact on climate change as we see. There's a question in the chat. Kira is asking us, was taking two rocks at one location for replicants? I can step in for you. No, I think it was just an opportunity. Thank you. Get a couple of rocks. I'll have a piece. I'd be very impressed with that. Yeah, if you get it wrong, that's nine wavelengths. Yeah. I'm starting to plateau a little here. Yeah, the sonars look pretty flat. Those are some of the sea urchins that we were seeing before. Are those the ones they call pincushions? I didn't quite hear that. Are those the ones that they call pincushion sea urchins? Yeah, they're actually quite soft. I'm hoping we will collect one at some point today. It's blanking on the name. I'll look it up. Kira, I don't know if you're listening, but any explanations for the way these rocks are pitted and eroded? I find it pretty remarkable that some rocks have sediment all over them that makes them starkly black. A little bolder. Smooth. Fairly different from what I'm wearing. Yeah, so we're interested in that, too. What different micro-colonized surfaces, types of rock. Does the mineral composition affect that? Is that a runaway dump where people... Yeah. We were experiencing that in those pareia fields. Of course it was when Jake and I were flying. You can have some more sediment on this plateau. So for the colonization experiment, we'll be deploying those when the oxygen levels are correct in the water? Is that my understanding? Yeah, we'll try and get quite a bit shallower, but if we need to make space to collect things, we will for now. So we'll delay it as long as possible. Roger that. Do we still have open space in the toolbox? I believe there is two rocks for the colonization experiment, so... We have four wood space. One. We have blocks of wood in the starboard box that we need to get rid of before we can put anything in. Roger that. So to all of our viewers right now, the light that you're seeing is just from the RO... Can you guys hear me? Am I loud? Yes, we can hear you, Lisa. I must have muted something. We can hear you. Very loud. So the light that we're seeing right now is just from the ROV, and we're at about 950 meters deep, which is just shy of where the last little bit of sunlight can penetrate to, which is 1,000 meters. Can it really get that deep? I always thought it was like 200. Depends where you are. So the turbidity of the water, is that what you're... If you're off La Jolla, you'll be in pitch dark at 20 meters most of the year. But in the middle of the Pacific, being in a submersible 500 meters down, and we can still see a little bit of light, it's very... There's whole areas of reefs, tropical Pacific, with very clear water, that you can still have algae growing down at 100 meters. Exactly. 200. 200. Mesophotic reefs. Now, one of the deepest known seaweeds was collected with a manned submersible, the Johnson Sea Link submersible. They named it Johnson Sea Linkia. That's great. Oh, there's a prey. Prey up to the left. Look at how the oxygen drops. Might be a rockfish. Or a really long, fine sea urchin. That's a big difference from yesterday's dive. One or two scattered... Add one more step. Five zero meters. One, two, zero. Bridge now. Change the speed to 0.3. Well, when I first called him in, I said 0.3, and he said 0.3, but I think it's because of our high wind and high current that it's been... I don't think it overthrew. And then this last one was 0.3. Thanks, Ernie. Do you have an estimate of the current speed here? Down the sea floor or up on the... On the sea floor. I'm not really blowing that hard. Once we're done with this transect, we can let ourselves sail in it for a second and see how fast we go. But I'm not really blowing that hard right now. Fair enough here. We're on a very, very flat area right now. Floor will start to slope up again. So we've got a long, straight, flat area ahead of us now before we begin to rise again. We were hoping we might be able to do some push coring. Yeah, I'd be curious to see how deep these sediments are, if they're deep at all. We can try and settle down. But I'd say it's probably pretty shallow. Yeah, it's pretty shallow. Pretty sandy. We can even poke it with a manib. But I don't think that coral will go very far. There's a... I guess go ahead. I'm really curious about all these circular pits and rocks. It's one of the large yellow sponges we sampled recently. It's a glass sponge. Beautiful yellow bars. And the feathery things we're seeing scattered around are this one on the right. If you feel right now, that's a filter feeding sea cucumber. It attaches permanently to rocks. We have another kind of sponge on the left that we sampled earlier as well. A very delicate glass sponge. Some quite interesting sediment right here with a big burrow. A couple of big burrows in the mud. Who do you think lives in there? That's a good question. I do. It's quite large. So Greg, take a look. The oxygen is really dropping. Yeah, the oxygen is suddenly dropping. We're really pretty flat. How much longer on the transition? Oh, just another 15 minutes. Did you want to... Did I... Didn't hear that. Sorry. You said 15 minutes? 15 minutes. The sediment is looking a little thicker. Yeah. Let's see where that burrow hole was. Are you looking for anything particular other than low oxygen? No. We'll put them out on a rock somewhere. Somewhere kind of visible. It gives us the best chance of finding it again. Is that why you want to put them on a rock base and not the sediment? Not getting covered? It would be unlikely to be covered in the year that they're down. But somewhere prominent. It would be very hard to find. Even if you're 10 metres off. The narrow light beam of ROVs. It's amazing how hard it can be to find things that you've put down. So that's why we tag things with reflective tape and little floats. We'll have a very accurate GPS location from the crew here. But it still can be a challenge to find things anyway. We just had a comment in the science chat from Kristen Little. She said we had just flown over a thorny hedge. And apart from the ray, it's part of the dive. We haven't seen exactly many fish. That's absolutely true. Especially compared to previous dives. That's the end of the transect right there. Thank you. Would you like me to hold the ship here? Or just keep moving until we find some sediment? Keep going. If we see some reasonable sediment, we might try and poke it. See if we can get a sample. We also got an answer from, I think, Paul's question from earlier about some of the topology of the rocks. The circular pits. And Kristen Little has replied saying those pits are quite common erosion features of the fault. And then Mary Wickston also chimed in saying that those circular features or those burrowing holes that we just saw could be from burrowing lobsters. The biggest of those being a Chalineopsis. But no Thalma. Kiera also chiming in to the question about the rocks. Looks like a lot of the types of rocks that we're seeing look to be mostly broken debris that has fallen down slope. And then the circular depression in the rocks. Again, echoing what Kristen Little has said. These circular depressions are likely due to uneven weathering and erosion. That is a header cone. Or it was. Dead header cone. Those ozodacs are for burrowing lobsters. Oh, I know. The boneworms who are interested in getting on the bones are usually bright red because they're full of hemoglobin, blood. They have a blood pigment similar to ours. So they're aerobic animals. They can tolerate very low oxygen because they have so much blood. But their bacterial symbionts that live in their roots that they use to dissolve the bone also are aerobic bacteria. So they have a pretty heavy physiological demand for oxygen. They are able to tolerate low oxygen. But the biggest ozodacs we ever find are usually in the very deep sea. 2,000 meters. That's where the oxygen levels are usually not too bad. We find small ozodacs in shallower depths. Less than 1,000 meters. Okay, we've just finished that ship move. We're in this kind of flat pit here. And we're meant to go to point Q. Do we want to head down that direction? Uh, yes. If that's the track, please head that way. Sure. It will get steadily steeper. And possibly we'll be cross-cutting those contours. But if it gets too steep, we'll go perpendicular, upslope, and laterally. Got it. 175. So is your interest in low oxygen to replicate the first one? Or... We want to... 100 meter step, bearing 175. Thank you. We've put out these wood, rocks, and bones at a relatively high oxygen level. And then we want to just contrast the things that will colonize at a lower level. I'm expecting we might get different ozodacs. If we can get a few hundred meters depth difference. And Lisa would like to see what other different kinds of animals might be tolerating a lower oxygen relative to a higher oxygen. And we'll do this at two different sites on the cruise. So in a few days we'll put the other pair of sets out. We're seeing the oxygen decline pretty quickly now. We're just seeing more beautiful foray of sponges. Otherwise we've got scattered solace or solity filter feeding sea cucumbers. We've got a bunch of them kind of spotting over those rocks. Do they stay in one place or are they going to move around a lot? They can move a little bit. But really they are almost like a sucker. Their whole bottom part of their body becomes very thin. Transparent actually if you flip them over. But the upper part is quite armored with plates to protect them. They can pull those feathery appendages in if someone comes to attack them. Because they're very unarmored and used for feeding. So try and get those out of the way if they get disturbed. Science while we fly, is it okay if we also use this opportunity to keep and get clear of the hose while we keep on flying? Oh that's a good idea. Can someone grab the arm please? Go ahead Jake. Do they eviscerate? I haven't seen the solids eviscerate. They don't seem to be able to do that. They might be able to regenerate though if they were attacked. A lot of sea cucumbers have this amazing ability to lose most of their internal organs. They can just grow them back. Some are even more specialized with parts of their guts. Which they would tend to squeeze out first. Very sticky threads that will gum up the mouth of a predator. The moment they hit the sea water they absorb the water and become amazingly sticky. If you ever accidentally tread on a sea cucumber in many of the tropical reefs you'll end up with these wide long threads all over your legs. It's pretty hard to get off. Interesting natural glue. Turn on the suction. I remember a seminar I heard many years ago. It was called autotomy and evisceration. What a title for a seminar. I learned all about this idea about when they're harassed they basically give up something to the predator. Go away. Sacrifice some of their innards. We don't see it that much in the deep sea ones. It's mostly the shallow reefs that we see that. Where there's just so many more much greater biomass of fish. Here in the deep sea apart from the solace there are these very delicate very transparent water filled sea cucumbers that maybe aren't a good meal. So predators don't seem to go near them. Interesting when you think about it though. Sea stars too will give up their arm. Or brittle stars. Maybe it's a common anoderm strategy. The idea of self mutilation. Yeah. Crinoids or feather stars have special they have their arms have an internal skeleton and they have break points on their arms that snap off if someone bites at them. It's like a pre an easy to break suture that allows them to give up the arm without really suffering major damage. Hopefully that's enough to release the predator. Come back a few weeks later and there's a little arm growing back out of where it broke off. Alright I think Argus is starting to move southward. Roger that. Some sea stars are able to just fragment into many five or so pieces and each piece will then grow a new sea star. So they have an asexual reproduction on all of them. It involves just fragmenting into their various arms. Then you find that arm and it will be growing four new arms out of the front. The original point of the arm where it attached to the body. What's this thing coming up? It looks like a Venus flytrap anemone coming up in the field now. That's super cool. Wow. It's the first one we've seen on our watch today. Yeah. We have a question in the science chat from Kristen Little. She's asking what depth is thought to represent the emergence line for the seamount? That could be important for interpreting the erosive features seen on the rocks here, i.e. submarine versus sub-aerial weathering. That's a great question Kristen. I just got the PDFs recently and haven't scanned through to find that out. We'll get that depth and get back to you. We have Kira in the lounge. If you have those PDFs, could you see or do you know where San Juan once emerged to? How's the clearing of the slope going? Any progress? I haven't seen any. Little red jelly or maybe a ctenophore? I think it was a ctenophore. Very cool. There's a little tiny bit of the yellow that we were looking for. Oh, yeah. Fantastic. Jake, you're doing great. Coming out in fragments is perfect. We have another comment in the science chat from Mary Wixon who is asking if we could get a good view of one of those slender red shrimps, that would be worthwhile, as this could be the first report of this unit in California, even if it proves impossible to identify any farther. So if we see any more of those, try to get a couple of screen grabs. Okay. Sure thing. Am I starting to hit upslope again? I'm leveling off. I think that is going. That'll be flat again. Yeah. Follow the track. Kira has replied in the science chat to our earlier question about the depth of the emergent zone for this San Juan Seamount. Kira says that the San Juan Seamount was indeed subaerial for about 1 million years. It reached elevations of 460 meters, which would be modern water depths of about 700 meters for the emergent line. So we might well reach that on this dive. We're at 950 meters now, so we could get up another 250 meters. Might be stretching to get that close today. We are going to add another hour on to the dive today. Making some good efforts there, Jake. Zoom on that thing in the middle. Not sure what that is. Yeah, let's do it. The yellow circle? Yeah, what is that? Is that a spunk? Maybe it's just a big spunk. I'm going to give you the camera there. Oh, we don't have our video person there. Fixing a camera issue. Okay, no problem. Looks like a collapsed skeleton of a... Or is it trash? It looks like a skeleton of a heterogon. Big skeleton. With a lot of detritus on it. Another type of sponge on top of it, right? Yeah. Okay, no worries. Keep going. Getting close to your target. You in? Sorry? Is that good there? You are below 10. I'd like to go below 10. No, you're good there. Thanks, Jake, for trying to get that thing clear. Yep. I think we got one yellow bag. Fantastic. Yeah. That's great. Maybe there's some other smaller bits we just can't see right now. I tend to have tough luck with the cup corals. I tend to get stuck. That one is pretty small. If anything, it's got a tongue up on the yellow thing. Yellow branching. Which is unfortunate. If it was small enough. Roger that. Got Steve looking for Al, and I tried plugging in her camera, but... So, Jessica, did they tell you guys we were going to extend the dive for an hour, or did that word get passed on? Yeah, that word got passed on for us, yeah. So we'll probably do a watch change at 4 o'clock, and then come back on for a shower leave. Try to cover as much ground for you guys as we can. Yeah, if we could get a zoom on some of these shrimps, they just capture a couple stills. Yeah, definitely. That's fantastic. Hopefully these are the shrimps that Mary Wick sent us. All fantastic. Is that the one, Mary? The one? The piece on the side? Get the lasers on the side? Just slurp it up? They're not so easy to slurp. I'm going to try to run. They're very, very, very sweet. Yeah. These are wild. The pan to the right, there actually is a sea urchin just there. We haven't really had a close look at either. Sure thing. Come a little wider, Jonathan. That's not a spot prawn, I assume. No. Come a little wider, Jonathan. There it is down there. Still get that in the frame? Sure thing. This is an echinotheroid sea urchin. They're very venomous, actually. If we get one of these on board, we'll be handling it with care. Mary said yes, that's it. One of them on the left. Yeah. We might have captured that shrimp. See, it's got a lot of long tube feet coming out. Waving in the breeze. And also, it has a lot of little spines. It can really do some damage. Underneath, it has little scoop-like spines that help it walk along. That's a lot of green detritus here. That's probably what it's eating. Okay, thank you. All right. Will it like to scavenge kind of the detritus off the rock? Off the sediment? We saw a kelp fall earlier, and there were three of them on a piece of kelp. Looks like salt rock. It looked like in that flat bit, it wasn't just a slope change. It was a sheet flow versus the columnar depth. Interesting. Roger that. Thank you. Bit coming up in our sonar. Roger. And in Perth Visual. There it is. Coming up. Two parts of the rock. Group 10. Thank you, Paul. What's happening? Hello. It is a minus quad lobster. It's probably not a tuna crab, which we do see shallow. Looking at the genetics of the tuna crabs along the western Pacific. Trying to fit them into the picture. They're in their own genus, Pluripotens, of the tuna crab. These ones are probably called munita, but it looks like it's a bit of a taxonomic mess. So we did sample some munitas yesterday by chance with the rock. Is that a coral there on that rock? That's one of the yellow bryozoans we saw earlier. Down there. Jonathan? That's another Acanthogorgia. That's the one we had already. There's a couple little clips of it. Do you see the bryozoan? Yeah. Oh, that one. Yeah. We were looking at it. Different one. That zoom is incredible. Definitely helped by such clear water. You can see it in the Argus camera up here. Just how crisp it is. Beautiful to find inside it. And what's the depth difference between Argus and Irving? It's changing, but it's around 15 to 17 right now. Meters? Meters, yeah. We call it the delta. Delta depth. Crisp and little. There's some nice tubular lava. Zoom here, Jonathan. Great. Steve is saying that the Acanthogorgia is carpeting at the top of the summit on the southern side. That crab looks ready to roll with us. Yeah. You going to keep coming up there, Steve? If that's what you want, I can go along contour. And then we can go straight up slope. Might be a little bit better, yeah. I'll turn towards the ridge. We'll be going 205. And then we'll just jog over the ridge now. Change course to 205. Sorry, science. We're just trying to get ourselves a bit situated here. Yeah, just the angle of this slope on the way to Q. Instead, we're going to kind of come along contour. If you're looking at height back for a little bit, and then go straight up slope. Okay, yeah. That might make things a bit better visually. I could probably still grab a bit once we're that close. You want me looking 205? Stand by. We'll wait for the swing to go out a little bit. What we're looking at here is a slope with lots of broken pieces of basalt, which is mainly lava. You can see there on the left, though, that's a lava tube. It must have been a spectacular sight. And this is gradually breaking up, fragmenting into boulders over the top of the slope. You're seeing quite a lot of... Yeah. I'll bring these around. This is more a convergent. Mesh-like structure. You can see there is a dead skeleton of a very large glass sponge. All right, Jake. Go ahead and come around to 205. 205. I want to be looking into the dark. We've got a few other glass sponges that are bright white that are alive. But we're seeing lots and lots of skeletons of these dead sponges. The yellow ones are dead. Yeah. Some of the glass sponges will have a coating of sediment or on the outside. The ones we've been seeing when they're alive are bright white. We're down at 7.5. Yeah, we're seeing a rapid drop in oxygen and quite a lot of corals are starting to show up. I don't know how much time you want to leave your deployment considering it took quite a bit of time. Why don't we deploy when we can leave it to the others? Oh. Is that what you're thinking? Oh, okay. I see your strategy. We can deploy if we want. We'll continue climbing up the mountain? Yeah. We'll have the fun. I'm okay with that. We would like to get a little higher before we do anything. If we need to put things in the biobox, we'll have to put things down. So we're going laterally along to a constant depth right now until we get in a better position and start ascending. Then we'll go up. We're at 100-900 metres now at 890 degrees. Our goal depth today was about 500 metres, but it's unlikely to be that shallow. We hope to come. We're still planning tomorrow's dive. We started late today. We've extended it by an hour. We're deciding if we're going to dive here again tomorrow or potentially on the other side. I'm kind of going back in time on a little bit of the chat, but I'm curious about the structures we're seeing. Crispin Little had speculated that some of these circular structures, the erosion structures that we're seeing, have been formed by rock-boring echinoids when the female was much shallower depth. Could that have been possible? Yeah, I'm certainly aware of that phenomenon in shallow waters, Crispin. We don't have the kind of urchins at this depth that are doing that. And historically, though, we do see them. Things like Strombolus centrodus. Here comes another one of those shrimps. 200 metres. Looks like there's a few. Do you want me to zoom on one? Yes, please. That's possible. Yeah, can you slow down and we'll have a look at this little rock? There's a couple more shrimps here. Go ahead and zoom on in there, Jonathan. That's great. We'll just kind of pan over the rock. This is the shrimp that Mary Whitstone alerted us to that could be a new record. Can you come still for a bit? She's been passing over more of them, and Mary's been letting us know. I'm not sure if this is called surgesties or not. All right, a little more zoom there, Jonathan. Thank you. Fabulous. Wow. Look at the brittle stars. Look at those long, whimsical features. Vintages. Scavenging on the rock as well. Oh, very cool perspective. It might not be a bad idea to get another sample of that Anabergia. Once we've got it really small and get that nice piece right there. Would you like to stop? Yes, please. Can you get the bridge now? Oh. What a chance. That's a cool rock. Hold position. Very wild. We're expecting a little bit of a swing, but we can kind of move on. We'll probably see another one in the next few years. Okay. Yeah. Next decent-sized coral. Yeah. As we settle out, we can. I'm sure we'll find another one. If not, we have the breadcrumb trail of where we just came from. Two. Hold on here. Let's see how much we're swinging. Standing out a bit. Oh, no. Is it on the crumbly? Yeah. Roger that. Avalanche waiting to happen. So, we're going to sample this coral. It's called Acanthogorgia. It's an octocoral. They have eight tentacles compared to normal or stony corals that have multiples of six. These are corals that don't need light. They just feed on what food comes by in the plankton. They don't have a stony skeleton. They have a skeleton that holds them rigid and made of various kinds of proteins. We'll get a nice zoom and we should be able to see the polyps that are out. You can see them in profile there. Each little cup has eight tentacles coming out. The surface of the rock is covered with brittle stars. We can see their arms, their long snake-like arms. Full zoom there, Jonathan. Keep going in if you've got it. All right, Jonathan. Full length. Okay, Jonathan. Go ahead and push down a little bit. Thank you. A little wider. That's great. I'm not digging that at all. Great. We're going to be aiming for the starboard biobox. Roger that. The position in between the four bioboxes. We're going to be aiming for the position B, which is more towards the aft, between the four bioboxes. Sample solo coming on. Sure thing. Camera quick. Roger that. Sorry, science. Can you repeat where the position will be for this? Absolutely. We're looking at the starboard biobox. We're going to go for that in-between section, more towards the aft of that biobox. Not in one of the four bioboxes, but that aft in-between section. Roger. Thank you. Roger. Basically, where we put the other samples before? Exactly. The sponges and that other exact one like this. Sure thing. We're going to give this a new sample number. Roger. Yes, and that new sample number is going to be NA124045. Roger that. Are you going to be able to tell this one apart? Yeah. This one, I think, is a little bit larger. It's balanced on the box there. Ah. Okay. I'm just tingling off my fingers there. Let's do something different here. It looks like it's going to go in that way, right? Yeah. There we go. It's sinking down. Thank you. Sure thing. Do we think the slope is working, or we'd have to test and see if it's okay? For sediment, it might be all right, but yeah, I think there's still things in the hose that haven't come out yet. Okay. Is there a sediment sample here that you're interested in? We can check. Yes, we can.