February 13, 2018

E2 – Science at a Glacier’s Edge

Posted by Shane Hanlon

 

In southeast Alaska, a team of scientists faced boat-blocking icebergs, calving-induced tidal waves, and cold, dreary days. All in the name of science. Using a hogde-podge of instruments ranging from radar to drone boats named Rosie and Casey, these scientists set out to brave the seas to understand a glacier.

In this episode, listen to oceanographer David Sutherland describe his experiences at Le Conte glacier, the southernmost tidewater glacier in the northern hemisphere. Sutherland and his team are trying to figure out what processes underwater affect how fast the glacier melts—their research in Alaska will help scientists studying glaciers from around the world.

Read more about David’s research on Eos.org.

 

TRANSCRIPT

Shane Hanlon: Welcome to the American Geophysical Union’s Podcast about the scientists and the methods behind the science. These are the stories you won’t read in a manuscript or hear in a lecture. I’m Shane Hanlon.

 Nanci Bompey: And I’m Nanci Bompey.

Shane: And this is Third Pod from the Sun.

Shane: So Nanci, you’re…you don’t have a science background right? You’re a journalist by training.

Nanci: I have a degree in chemistry, Shane.

Shane: You do! Oh crap, I had no idea. Oh wow, I apologize.

Nanci: Not a PhD but I do have a bachelor’s degree and I worked as a chemist.

 Shane: Okay, well, that’s…I legitimately did not know that so I learn something new every day. But, no, what I actually wanted to ask you about was there was uh, there was, we were kind of joking in the office sometime last year about you being an honorary oceanographer. What was that about?

Nanci: So, yes. While I do have a degree in chemistry, I do not have a background in geoscience. But, a couple years ago one of the editors of one of our journals at AGU invited me to go on an ocean research cruise with him and his team out in Oregon. They were at Oregon State University. So, I went on an ocean research cruise, it was just off the coast of Oregon for a few days but it was awesome. Got to do the whole thing, got to sleep on a boat, got to help them with the CTD’s which is this very common oceanography thing. Got to see them in the lab, stay up late, had some rocky seas. So, it was really cool, I think I’m definitely an oceanographer after that, basically.

Shane: I have to say I’m jealous. I am a…I guess we’re both scientists by training [laughing] but I pursued science but I didn’t get to do anything quite that exciting. My most exciting, I guess, voyage was riding around on dinghies in ponds setting up turtle traps. So I gotta say, I’m jealous.

Nanci: It was pretty cool, it was pretty sweet.

Shane: Well I will say though, you are an honorary oceanographer and I’ve never quite had the experience or opportunity to be part of that but, maybe, we can live vicariously through an actual oceanographer. So for that, let’s bring in our producer JoAnna Wendel. Hi JoAnna.

JoAnna Wendel: Hey, Shane.

Shane: So what do you got for us?

JoAnna: So I have a story for you about the place where ocean meets ice. So this ice covers about 10% of Earth’s surface, much of it in the form of vast sheets or glaciers. And, glaciers which are like huge tongues of ice that slide and glide across the earth are a real hot topic in climate change these days. These glaciers creep and retreat as our climate changes over millions and millions of years. Even parts of the United States were covered in glaciers at one point. But, right now, scientists are concerned with how human activities cause these glaciers to melt and retreat. So, things like releasing to much greenhouse gases, like carbon dioxide or methane, this traps heat in the atmosphere and warms it up causing glaciers to melt and retreat. Industrial activities like farming and burning fossil fuels in forests also send a lot of dust and soot into the atmosphere, which also, end up falling on the glaciers causing them to melt and retreat. It’s this huge complicated process and scientists use a lot of tools to study each little tiny piece of that puzzle. And to learn more about how scientists study glaciers I talked to this guy, Dave Southerland, and oceanographer at the University of Oregon. So, back to Oregon, which also happens to be my alma mater. So, Dave and his colleagues have recently been studying this glacier called Le Conte in Southeastern Alaska, and they take these research cruises there, you know, every couple of years.

Nanci: So, let’s hear from Dave about what he’s doing.

Dave: I study where fresh water meets salty water. Places in the ocean where rivers meet the ocean or solid fresh water like ice, where ice meets the ocean. It’s really where I think really the most interesting questions are. It’s where people live. In particular, estuaries are where the majority of the coastal ocean is, where the majority of people live in the world. Then in the high altitudes say around the Arctic or Antarctic, it turns out the areas around ice sheets and glaciers where they meet the ocean is really where a lot of change is happening. It’s where we need to understand the processes that are going to control sea level rise for instance. If you want to understand how global climate change is affecting our world, we need to understand where ice meets the ocean.

The research we’ve done over the last two years took place in the Le Conte Glacier in La Conte Bay in Southeast Alaska. We call it a tidewater glacier or a marine-terminating glacier and that just means that the ice that drains a big ice field up in the mountains actually drains down into the ocean and it empties into the ocean. So it calves off icebergs, water runs off directly into the ocean, so it’s in that environment of sort of a swirly mix of ocean currents and berg-y bits and icebergs that we were trying to get our measurements.

We went to Alaska actually to study processes or study the physics of a situation that we think applies, not just to Alaska glaciers but also to Greenland glaciers to Western peninsula glaciers to Patagonian glaciers. It’s really what does the ocean do to the underside of these tide water glacial systems, so the ocean obviously, when you put ice in water that’s warmer than the freezing point, it melts but what we really want to understand is the rate of that melt and where it happens. That’s the main question, is what control does the ocean have on the melt rates of these glaciers.

If we can understand that, then we might understand how the glacier calves, so by calving, I mean how ice chunks break off and become icebergs.

Shane: Why Le Conte? What’s so special about this glacier?

JoAnna: So, actually, the people near this glacier have been studying it since the 1970s.

Dave: If you know anything about Alaska, it’s very alive, it’s very wild. There’s eagles, there’s whales, there’s seals, there’s salmon, there’s goats. The mountains are high. There’s ice everywhere, and so it’s this really sort of adventurous place and everyone has sort of a feel for nature there because they spend time out in it.

To go to La Conte Glacier, you fly in and out of a town called Petersburg, Alaska and it’s this really small town, you know, like 2,000 people, but they’re connected to the ocean so everyone has a fishing boat or they’re connected or they know someone with a boat or they hunt or they trap and so everyone’s really interested what’s happening with the glacier and what’s happening in Le Conte. It’s fun just to walk around town and meet people and you talk to them and you explain what you’re doing and they have a really excellent knowledge of the ocean there as well. They not only want to hear what you say but they actually tell us things as well as scientists. It’s really, it’s one of those areas where we can learn a lot of science just by listening to the local people.

It was a program started by the local high school, started surveying the glacier back in the, I want to say the 1970s where every year they’d take high schoolers up to look at the glacier and they take pictures and they survey it. They trace out where it is. It was in the 1990s that they noticed that this glacier was starting to move back rapidly and they contacted some scientists up at the University of Alaska who’s one of the co-scientists on this project that we’re involved in. That led to a, for the past 20 years, people have been studying this system in some degree or the other. It was really because of the local engagement with their environment.

Nanci: That’s cool! But, I mean, they’ve been taking these measurements for so long. Why?

JoAnna: So, what they want to know is what happens to the glacier as ocean waves continually lap against its face. Especially that place hundreds of meters underneath the water – that place you can’t see with your eyes or observe with a satellite.

Dave: The underwater environment is always the most challenging part to see. We have amazing satellite data these days, right? You can go on Google Earth and you can go look at all these glacial systems and fjords, down to really high resolution. You can identify people and cars but if you try to look under the ocean, right, you can’t do that from satellites. So, as an oceanographer, we have to go out in ships and think of ways to image the underside of these, not just the ocean, but the underside of these glaciers that end often in really deep fjords so we’re talking about fjords that are hundreds of feet deep, half a mile deep sometimes and so you just, a lot of the action is happening. I mean literally, the tip of the iceberg is like a real thing, so we really want to understand the rest of the story there. Most of the story is underneath the water.

Shane: Alright, what I want to know is how do they study what’s happening underneath the water? Right, because it’s really cold, it’s dark for half the year, there are giant icebergs floating around…so what gives.

JoAnna: Let’s start from the beginning. So, these scientists—12 of them usually—go  out on an ocean research vessel, that’s normally a fishing boat and they spend like a week and a half just kind of sailing back and forth in front of this glacier gathering as much data as possible in that time period, and they use a lot of different instruments.

Dave: We had a science crew and then there’s a crew on the boat who was operating the ship the whole time so we didn’t have to worry about operating the ship, luckily. Then we ran all the instruments as well. We had a team of about 12 people on board running 24 hours. All day, all night, rain, no rain, whatever conditions we had.

So we get on board and there’s only maybe five bunks and we have 12 people for a science crew. We had to do what’s called hot-bunking, which means that there’s always people awake so you can share a bunk with another person because you don’t ever sleep at the same time and so the galley, the galley is what in the ship is where you eat dinner, where the food is cooked, it’s like the kitchen. That’s sort of the center of this boat. There’s the galley and then there’s the outside, the back deck.

So, when I wake up, you go out into the galley, you go look in the back deck and there’s always something going on, there’s either like the crane lowering something into the water, there’s people attaching instruments to things, taking instruments apart, looking at data on the computers. There’s always a lot of activity going on. Then there’s the crew. There’s the cook making food in the galley and there’s the captain and his mate up on the bridge sort of making sure that we’re safe. There’s a lot of activity that every day, it was different but sort of the same activities going on from day-to-day.

So when I would wake up, I was on the 4 PM to 4 AM shift. I would check in with my other lead scientists on the boat and say, “Hey, what’s been going on? What’s the plan for the next 12 hours,” and we’d sort of develop a plan and go from there.

My favorite part about being in the field is just being totally focused on one thing. We don’t get cell coverage there, we don’t get internet access and so it’s really nice to unplug and just focus in on this one thing, right? We’re collecting data that we’re going to use for the rest of the year so my favorite part is just being outdoors really for 10 to 14 days at a time and not really worrying about what’s happening in the world elsewhere. That’s really nice. It keeps you going the rest of the time when you’re sitting in front of your computer banging your head on the wall about your data and everything else or your code not working.

That’s my favorite part and working in Alaska was just the icing on the cake and just seeing all the wildlife and the friendly people and knowing that what you’re doing actually matters to these people was just an amazing experience.

Shane: I got to say, hearing this is making me long for some time outside of DC.  And it sounds like the people and the atmosphere, like everything there, was just so amazing. But I’m assuming they actually got a lot of work done. What were they actually looking at?

JoAnna: They were looking at this thing called a subglacial plume. That’s basically a stream of fresh water coming out from the bottom of the glacier, underwater. The water starts as ice on top of the glacier and then it melts in the sunlight. Then that water streams down through cracks and crevasses in the glacier, sometimes making caves, and it flows out the bottom. Because the subglacial plume is made of fresh water, when it spurts out of the glacier it actually rises because the water around it is saltier. And it kicks up this salty, slightly warmer seawater and drags it upwards—which can help to melt the face of the glacier. But the thing is, the subglacial plume comes out 230 meters underwater. That’s not really a place scientists can or want to go.

Dave: Right now, the study of the sort of near glacier environment is really hampered by the fact that we lack some technology to make these measurements under the water. It was actually a lot of our thought processes was how are we going to make these measurements and how are we going to do it in a way that we can compare to maybe standard methods or have a couple different ways to measure something so that we can make sure that we’re doing it right.

What we needed measurements of were the underwater environment and so we took some techniques that were commonly used for other applications, so mapping the sea floor and we sort of adjusted those or adapted those to our own application.

In particular, we care about how the water moves, so we care about that. We call it the ocean circulation and so the water moving around tells us something about the source of that water so is it coming from the glacier or is it coming in from the outside of the fjord? The movement of that water that also helps it erode or melt away the glacier. Then the temperature of the water, we use instruments to measure the temperature of the water all the way down to the bottom, so from the surface, we lower it all the way down to the bottom so 600 feet, 800 feet down and then how salty the water is as well.

Then what we did as well was we used what’s called a multi-beam sonar. You can think of it just as a fancy fish finder, so like an echo sounder that you would just send sound waves that bounce off usually the bottom of the ocean.

What that is, it just looks like a big, maybe three feet long, black box that you stick on a pole and then you stick that pole underneath the water off the side of the boat, and it sends out sound pulses and those sound pulses then bounce back off whatever surface is out there. It could be the sea floor, or it could be the ice itself. We were going back and forth in front of the glacier, sending these sound pulses out and they were hitting the glacier surface and then coming back to our boat and we record that distance basically.

In this case, we tilted it to look at the ice face and so we were actually directly imaging the underside of the glacier. If you do that repeatedly, then you can actually see how the underside of the glacier changes, while you are also collecting the ocean data and everything else at the same time.

Nanci: I’m assuming that they couldn’t just take out their phone and take a picture, right?

JoAnna: Right. They also wanted to see what was going on with the glacier, so they used a couple actually different kinds of drones…they had drones that can be flown in the air and they had these remotely operated boats, which are kind of like kayaks with engines in them and they go right up to the face of the glacier, which is not where you or I want to be!

Dave:  I was actually the drone operator. I am official FAA-certified part 107 so I could even fly commercial if I get fired from my day job here, so I flew the drone.

Luckily, we’re in the area where there’s no airports nearby, there’s no other stuff that you have to worry about if you’re trying to fly something in a city for instance. We were never over top any people. We might have been over top some seals, but there you go.

JoAnna: They also had these remotely operated boats, called Robotic Oceanographic Surface Samplers, to study the glacier face even more closely.

Dave: The remotely operated boats are actually just heavily modified kayaks that they make commercially available, this company called Mokai makes kayaks that have jet engines in them. My colleague Jonathan Nash at Oregon State modifies them to collect oceanographic data at the same time.

The boats are also a little more expendable than say human life, so we can send them up to the glacier front where they might get hit by an iceberg or a chunk of ice calving off whereas we won’t go up to the glacier front on the real research vessel.

JoAnna: Ok, one more thing about the boats though—two of them have names! And there’s a fun story around how they got those names…

Dave: One of the first trips we took there in August of 2016, we get into town a few days early to set up the boat and to test things out and then at night time, we take a few hours off every once in a while. We were walking around Petersburg and one of our, this woman June Marion, who works at Oregon State noticed a sign outside the Sons of Norway Hall in Petersburg, Alaska, it said, “Wedding reception tonight. Open to all.” At first, we didn’t think anything of that until we started talking to some other locals and they were like, “Oh yeah, there’s this wedding happening and you have to be invited to the wedding but the reception is open to all.” We said, “Okay, but ‘open to all’, what does that mean?” They went, “Oh, everyone in town is invited.”

That just sort of blew our minds and so we decided to go because we’d met some people locally and June was really excited to go and sort of see the local scene and so we went to this wedding reception at the Sons of Norway Hall and the couple that was getting married were named Rosie and Casey. We met them and they were very nice and we were so inspired by their wedding and their openness and sort of just their welcoming nature, which was really representative of the whole community, that June decided to name the boats after them.

Shane: Life goal: get a science boat named after me. Nanci, maybe we should start talking to scientists with know to get some Shane & Nanci boats out there!

Nanci: Totally, but as fun as boat-naming sounds, it can’t all just be fun and games, right?

JoAnna: Right. Well, it turns out there’s probably a lot of ways you can die when you’re on a boat in the middle of a bunch of icebergs.

Dave: From a safety point of view, obviously when you go into these fjords on a ship, you’re not going super fast so there’s no risk of like of doing a Titanic, right, where you’re going to run into an iceberg at such a speed that you blow a hole in the hull, but what can happen is you can get scrunched or crunched by icebergs coming together or you know, repeated hull bashing by ice is not good for the boat and so you can weaken the hull. There are safety concerns like real safety concerns of operating in these areas. Then once you’re close to the glacier, you have to worry about really large calving events. Le Conte Glacier sort of calves off these, we call them small bergs but they’re sort of car-sized bergs and berg-y bits and those are fine, they create waves that you can just ride out. But if a really large full-width iceberg calved off, you wouldn’t want to be very close to the glacier because it could lead to a, in the best situation, your boat just rocks a lot and everything falls off the shelves and everyone sort of falls over and maybe lose some equipment. In the worst case, your boat gets swamped and maybe lose someone off the back deck or something like that.

Those are the things that we have in the back of our minds when we’re working there. We take that all into consideration. We didn’t do anything that was unsafe in this field work, we were definitely close in pushing the boundary I think, but we’re always within a distance where a piece of ice wouldn’t have come up underneath us and hit us, that’s the other worst-case scenario is that these glaciers can sometimes have tows or things that stick out underneath and they might just pop up underneath your boat and that’s when you don’t know that it’s coming.

Shane: Okay, this is freaking terrifying. Imagine watching a piece break off, thinking “Oh, good thing we weren’t under that’, and then it comes up from below.

JoAnna: Well, okay. That wouldn’t probably happen but, you know…Despite the dangers, Dave loves working at this glacier. It may not be as large or awe-inspiring as the glaciers in Greenland or Antarctica, but Alaska is just beautiful. And the work they’re doing can really help us understand the hundreds of glaciers around the world.

Dave: The real sort of ultimate goal for this is to inform these big climate models that include

everything. They include oceans, they include ice sheets, they include the atmosphere. They have to do all this at a scale where they’re not actually, they can’t see an individual fjord or an individual glacier, so what they do is they have to parameterize things so they have to come up with a way to say, “What is the effect of that process,” in this case, ocean melt or how the ocean melts glaciers, how do they include that in their model in their big climate model?

What we’re doing is going to help inform those climate models to say, “Well, how do you take that into account, because this is really an important process because this is ice sheet change that accounts for 1/3 to 1/2 of all sea level rise currently.” We have to get it right. That’s the goal.

Shane: So, Nanci, does this make you want to be an actual oceanographer?

Nanci: So it sounds super cool, but honestly, I think those three days on a boat with those scientists from Oregon were enough for me.

JoAnna: And, if you want to find out more, check out my story about this research on Eos.org.

Shane: Alright folks, that’s all from Third Pod From The Sun.

Nanci: Special thanks to JoAnna for bringing us this story and editing this interview, and of course thanks to Dave for sharing his amazing project with us.

Shane: This podcast is also produced with help from Lauren Lipuma, Josh Speiser, Olivia Ambrogio, and Caitlyn Camacho. And thanks to Kayla Surrey for producing this episode.

Nanci: The AGU would love to hear your thoughts about this podcast. Please rate and review us. Of course you can find the latest episodes on your favorite podcasting app or at thirdpodfromthesun.com.

Shane: Thanks, all and we’ll see you next time.