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The Future of Sable Island

Southeast of mainland Nova Scotia sits "Sable Island", a small crescent shaped island home to magnificent wild horses and one-of-a-kind wildlife. But with the potential impacts of climate change on sensitive coastal areas, can a small island made entirely of sand survive the forces of nature in the middle of the Atlantic Ocean? On this episode, we talk to scientists with new research examining the future of Sable Island.

Transcript
Joel Houle

About 300 kilometres southeast from Halifax, Nova Scotia, sits an island of sand. Appropriately named Sable Island, this small crescent shaped island is home to magnificent wild horses, as well as the world's biggest breeding colony of grey seals.  But with the potential impacts of climate change on sensitive coastal areas, can a small island made entirely of sand survive the forces of nature in the middle of the North Atlantic Ocean? On this episode, we talk to scientists with new research examining the future of Sable Island. Welcome to a new episode of Simply Science — the podcast that talks about the amazing scientific work that our experts at Natural Resources Canada are doing.  My name is Joel Houle. And joining me is my cohost Barb Ustina. Barb, how are you?

Barb Ustina

I'm doing just fine. I'm really looking forward to this episode! It sounds pretty fascinating so far.

Joel Houle

Oh, it does! Me too! Before doing research for this episode, were you aware at all of Sable Island?

Barb Ustina

Yeah, as a matter of fact, in a former life when I was working in broadcasting, I almost went out there to do a story on the wild horses. And I Googled the island. I did all kinds of research and I got really, really excited to do the story. And the story fell through. So I was really disappointed. So it's kind of a return for me in a way. I do know a little bit about Sable Island, but certainly I've never been out there.

Joel Houle

Yeah. I mean, it would be so amazing to go there! I was looking at pictures online. What got me, there are pictures of horses on the beach, and it's beautiful, but it's the pictures at night that I saw. The ones where, like, there's no light pollution. It really is starry skies, like you wouldn't believe. It's absolutely stunning!

Barb Ustina

I can't even imagine what it would sound like if you were staying there overnight and looking at the stars in the sky. Would you hear the winds and the waves from both sides? That would just capture the imagination. And it's no wonder that scientists have focused on this island for a good amount of time. Almost since it was first written about in history, the island, back in the 1700s, they were talking about — Will this island survive? So this has been a concern of scientists for a long time already.

Joel Houle

Yeah. And it seems like history is continuing ... it’s being made today with researchers from both Natural Resources Canada and from Parks Canada collaborating on research now. I don't think I've ever been as excited to cover a podcast. Should we bring in our guests?

Barb Ustina

Let's do it.

Joel Houle

Joining us today are Jordan Eamer and Dan Kehler. Guys, welcome to the show!

Dan Kehler

Hey, thanks.

Jordan Eamer

Thanks for having us.

Joel Houle

Maybe you guys can tell us a little bit about what you do. Let's start with Jordan. You are a research scientist with the Geological Survey of Canada. What does your work entail?

Jordan Eamer

I can wear a few different hats. Mostly I do research in the coastal zone, I guess you can call it. A lot of my background is in coastal geomorphology, which is just kind of studying how the coastal geology changes with time and different forces acting on it. Since I started with NRCan, I've been working a lot with inner shelf geology as well. So usually using a lot of remotely sensed data from boats or from satellites. And balancing that with a lot of the onshore coastal work, which is tramping around beaches and dunes and making observations.

Joel Houle

Interesting. And Dan, you're an ecologist with Parks Canada. What's your expertise?

Dan Kehler

Yeah, so I'm the park ecologist for Sable Island National Park Reserve. And my expertise is actually more in the quantitative side. So a background in statistics and in modeling.

Barb Ustina

Now, the two of you are doing some work together on Sable Island, which is off the coast of Nova Scotia, and for those of us who have never been there, and I'm sure that most of our listeners have never been there. Can you set the scene for us a bit? What's it like there? It just looks like such a magical place!

Dan Kehler

Yeah. Sable Island is one of Canada's furthest offshore islands. It's 300 kilometres from Halifax, which is where we fly out of. But the closest point of land is 170 kilometres. So it's really out there in the Atlantic Ocean. And you feel the full brunt of those oceanic forces when you're standing on the beach. The island is really well known locally, nationally and even internationally as a location. Part of the maritime history is a bit more somber because there were a lot of shipwrecks in and around Sable Island during the age of sail as it sits somewhere on the track between what were the colonies on the eastern side of North America and the old world of England and France and so on. So there are over 300 recorded shipwrecks. And then in more recent times, it's well known as the location of the famed and iconic wild horse population of Sable Island.

Barb Ustina

Jordan, from a geographical point of view, what makes this island so unique?

Jordan Eamer

Right. Dan gets to do all the magic and talk about horses, and I get to talk about sand grains and glaciers and stuff. I get it. So, yeah. The story of Sable actually, it does trace back tens of thousands of years. So it's a story of glacial advance and retreat. So over the last several ice ages, glaciers have pushed ice sheets or pushed an immense amount of sand and gravel out to the edge of the shelf, which is where the Sable Bank sits with Sable Island sits on top of. And all this advance and retreat just kept pushing more and more sediment until the last ice age that we know happened around 20,000 years ago. Just as the ice was retreating, it did one little extra advance. And that kind of pushed the last little bit of sediment up on top of this bank and built the island that we know as Sable Island today. So it's a story about ice being pushed to the edge of the shelf. And then as that ice retreated, the sea level was actually much lower. So Sable Island itself was humongous, it was probably 10 times larger than it is today. And over the last 10,000 years or so, as sea level rose, the island generally changed shape. And the sands have been better and better sorted as the ocean has been sorting this sediment and turning it into the Sable Island that we know and love today. What's really incredible about the island itself is it's almost entirely composed of sand. There's not an iota of bedrock that you can find out there. And there's very little bits of gravel here and there as well. So it's really fascinating.

Barb Ustina

Wow, it sounds incredible. Now, tell me a bit about the work that you're doing there, the research.

Dan Kehler

Sure. I mean, we've been ... since those sands have been sorted for so long, we continue to sort them by shape and colour. And I’ve spent a lot of time ... just kidding. I do manage most of the conservation programs that happen on Sable Island National Park Reserve. So that includes collaborating with some of the longstanding research programs and researchers who have been studying grey seals. The world's largest breeding population for grey seals. They were studying horses. It's been an important centre for atmospheric research. It has been and continues to be a weather station that's been operated by the Canadian government for a long time now.

Jordan Eamer

And I actually moved out to Nova Scotia to take a job with Sable Island National Park Reserve. And when I started, it was as an operations coordinator. So that was a very different job than I have today. It involved a lot of things — from fixing broken pipes and driving around and finding, you know, unexplored coordinates and finding runways for land planes on. But while I was doing that, my background in coastal geomorphology and geology, I was always kind of fascinated by the island. But I was kind of coming up with research projects and programs in my head. So it was nice to be on the island for months at a time and make all these observations and kind of take those observations with me to my current position.

Barb Ustina

 Now, are you looking at archival photographs as well to do a comparison of the past to the present that sort of monitor the level of erosion?

Jordan Eamer

So that's the current project that we're just in the process of publishing right now. So there is a really great record of air photos that have been collected over the islands historically since the late 50s. And what we were able to do, in partnership with the Nova Scotia Community College out in Middleton, was digitize them and — you call it georectify — so basically you're putting this into a common space so that you can compare air photos over time and actually do measurements with these air photos. So with Nova Scotia Community College and partners, other researchers that Natural Resources Canada and with Sable National Park Reserve, and Dan, we were able to sort of piece together how the coastline changed of Sable Island and the island itself over the last 60 years or so.

Barb Ustina

Just following up on that, what have you learned? What are these images telling you?

Jordan Eamer

Well, lots! One thing that's sort of the underlying picture ... and this is not a surprise to anybody who spent an appreciable amount of time on the island. The underlying picture is one of net shoreline retreat. So generally the coast is eroding there. So we kind of knew this from a geologic perspective, as we were talking about earlier. As sea level has risen over the last 10,000 years, the island has shrunk, shrunk, shrunk. But we are now trying to fine tune that picture to the scale of decades over the last few decades. We're actually ascribing rates now to this to this shoreline retreat. And what we're finding is that in general, the whole coastline along the southern coast is retreating. And that is offset a little bit by the north coast of the island. It's seeing a little bit of advance. But overall net around the whole of the island, it is in general, the coastline is retreating. And what's interesting is we were able to not only look at the shoreline itself, so where the ocean meets land. So we took it one step further and we looked at what's called a foredune. So it's sort of like the first kind of real chunk of the island, if you want to call it that. It's where the beach meets the land. And we looked at how that is migrating over that same time period. And that is a much more nuanced sort of result. And it tells you a lot about how the island itself is evolving with these changing conditions in the ocean. And one interesting find — we don't need to talk about all of it because I could — one interesting finding is that there was a big lagoon that turned into a lake that has since been infilled with sand along the southern shore. And all of a sudden as that all infilled with sand, that became an available source of sediment to continue to build that dune. Even though all the coastline is retreating on that southern coast, that dune is actually growing and moving landward at the same time. So there's a bit of a conflicting signal there. So it's just really interesting.

Dan Kehler

And it's really interesting to think back to recorded history for the island, which starts more or less in 1801 with the first permanent settlement. And we've got written records of how the island has changed in that period. So between 1801 and now. We also have some vague idea of what was happening since the last retreat of the glaciers. But this project really let us quantify the change that many people have observed on the island. And it's not uniform. And there have been some really large-scale changes in particular areas where freshwater ponds used to exist and have now disappeared with the loss of that protective foredune. But for us, at the National Park Reserve, we're still faced with the basic question of will this park be here in the future? And this is a question people have been asking for a long time. And back in 1899, they were worried that the island was going to disappear and become an even greater hazard to navigation. And that led to a discussion about what the options would be to save the island, including armoring the coastline with rocks. And what they settled on was a great tree planting exercise to try to stabilize the island. And that didn't go very well. In fact, all those trees died. So here we are in 2021.

Jordan Eamer

Sorry Dan for jumping in there. There's one — one tree left.

Dan Kehler

It was planted later, in the 50s. And calling it a tree is a bit generous since it's really about mid-thigh high. But anyway, here we are in 2021, we're still scratching our heads wondering what is the evolution of this island. Is it on a path to disappearance or should it be something that will persist? And how is sea level rise and climate change factoring into that equation.

Jordan Eamer

It's interesting, too, because this is a question that has been asked for so long. There's been a lot of hypotheses around what is the ultimate trajectory of the island. And they range from it's migrating east through time and it's going to disappear into the gully — as all the sand just gets dumped into the gully — which is the marine protected area there. Or it's maintaining itself by this complex web of sediment being transferred around the island, over the island and then back around the other spit. Or my favourite which is — I don't know if you've heard the term Ockham's Razor — but it's just the simplest is usually the right explanation. But it's actually just sitting there and as the sea level rises parts of the island disappear. So we were able to kind of ... the data, the results that we produced, weren't totally suited to answering that question. But we were able to kind of at least point in some directions. And in general, what the data that we produced looks like ... the results that we produced, it looks like that sort of closed circulation may be happening. Or again, that simple explanation that as sea level rises, it just kind of — you just lose a little bit more island. Maybe that might be the trajectory that the island is on.

Dan Kehler

And Jordan, what you and others have explained to me is that the island is losing sand through wind. The wind blows the sand away. So we need a source of sediment and that's a function of the wave action. But also, I suspect the currents around the island. Which have always been a bit of a mystery to me, because I know we have major currents, part of the east pushing northward, the Gulf Stream, and then major currents to the west coming down from Labrador. But yet there's a more complex interplay that's happening on the island. And people talk about throwing a boat or a piece of trash and then seeing it reappear, having completely circumnavigated the island. And that's one of the things that I'm worried about is ... if there are any changes to the current patterns due to climate change pushing the Gulf Stream further offshore or what have you, what that would mean for the ability of the island to still get that sediment that it needs.

Jordan Eamer

I should note that we don't advocate any visitors to the island to throw trash in the ocean. I think these are previous experiments — but yeah. And that's something that we touched upon. So I alluded to a paper that is coming out soon. One of the more complex studies on offshore currents has shown that there seems to be an eastward occurrence off the south shore of Sable Island that ends in a gyre. So it's not quite at the gully, which is further east of the island, but in that general area. And that's, if we're going to get into the nitty gritty, that's actually, that current kind of supports what our findings are. It's that everything seems to be moving toward the east on the South Beach. And then maybe that gyre is actually a source of sediment, like Dan says. And maybe in major storms that can get pushed up on the beach and continue to keep Sable Island moving.

Joel Houle

Wow, that's very interesting. OK, so this is a little bit off topic, but we can't talk about Sable Island without at least asking the question, even though that's not your expertise. The horses, where did they come from?

Dan Kehler

Great question. We have a pretty good guess. Although for a long time people thought they’d swam from ships that had shipwrecked off the coast. In fact, the best evidence comes from some written records from the middle of the 1700s where they were two merchants who bought horses and transported them to the island. Boston merchants. And in the latter case, we believe those actually came from Acadians who were dispossessed of their property in the middle of the 1700s. Some of those horses were bought by this merchant and dropped off on the island. But keep in mind, people used to do this all the time with sheep and other livestock because these islands were free of predators and it was a commercial venture. They thought they would drop them off, come back and harvest them and make a lot of money. But I think they underestimated just the difficulty of getting to Sable Island and also the fact that there were many other shipwrecked fishers and other folks who arrived on the island who needed a source of food. So some of the animals that were dropped off just disappeared. Cows and goats and what have you.

Joel Houle

Wow, that's interesting. Yeah. Thank you for indulging me with that question. So let's talk a little bit about your work process. So the two of you, how do you work together? What does a typical day on the island look like?

Dan Kehler

Well, in the days when Jordan also worked for Parks Canada, it was fun to collaborate on some idea generating. I remember Jordan taking me out in the Jeep at low tide and then digging around with a shovel at some of these old soils that are on the beach. And that sparked some discussion about how did it get there and what's offshore of the island and how do we figure out what the geological history of Sable Island is.

Jordan Eamer

Dan, got to experience some classic geology: drive to a spot, dig a hole. I think we still have those samples wrapped in tinfoil marked "this way up" in the freezer on one Sable, don't we Dan?

Dan Kehler

Hopefully not in the food freezer.

Jordan Eamer

It's in the sample freezer. I'm sure.

Dan Kehler

This work involves a bit of detective legwork just to find the imagery. So when we arrived, we didn't have the full historical record of the images. We didn't know what existed and where they were. So I think at one point I had to call in a favour from someone who worked for Parks in Ottawa to physically walk over to the National Air Photo Library and verify whether or not these photos existed. And we found them. We found the old ones. We were able to get them scanned and then sent to us. And then the rest of the imagery existed in various places. But there's one set we never found. There's a map. I have this map from 1983 and we know there was imagery created at that time. But the originals have disappeared. So that, unfortunately, is a gap in our multi-decadal data stream.

Jordan Eamer

But the work that we're in the process of finalizing right now, this air photo historical analysis, it's not very exciting. Unfortunately, it's a lot of desktop work. So we can't jazz it up too much. But I am looking forward to some future collaborations in the works. We're working with some of my old colleagues on modeling future trajectories of the island. So getting a better handle of how the island itself is evolving, but also getting a better handle of our infrastructure. How best to place infrastructure. What effect it's having on the on the sort of smaller scale. Wind flow patterns and how sediment is transported around the island because windblown sediment is obviously a huge component of daily life out there. You can't escape it. I did have the opportunity to do some fieldwork with my NRCan hat on. I guess that was in late 2019. And again, that was a classic coastal geomorphology trip where you just kind of — you start your day looking at some LIDAR, some elevation maps and you look at some air photos and you put a point on a map and then you just go and you just walk around. And you do a lot of arm waving and a lot of pontificating and then write it up in a report.

Dan Kehler

That reminds me of the first conversation I ever had with a geomorphological scientist, who I was trying to get advice about some of these issues. He said: "Oh, yeah, just have somebody come to the island and walk around and they'll be able to give you their opinion." Which to me, coming from a quantitative background, is that really how they do science over there? I learned so much on that trip that Jordan was talking about with himself at another coastal geomorphologist, just walking around. And visually, they can describe what's happened in an area just by looking at the patterns of the sand, the striations, the layering and so on. So I wouldn't call myself a geomorphologist, but I've got a few nuggets that I pull out from time to time if I need to impress someone.

Barb Ustina

Oh, definitely. Now, it sounds like it's quite a collaboration, the two of you working together. And are there things that you can do working collaboratively that you're not able to do if you're working individually? I think you've touched on some of those things already, but how does working collaboratively lead to different ideas of doing things or different ways of doing things and just sort of the sum of the parts are better, working collaboratively than individually?

Dan Kehler

Well, it's easy for me to start answering this because we are heavily reliant on the expertise from outside scientists for all the work that we do. So we're not trained in coastal geomorphology, we're not trained in image analysis. So to be able to get this project together took all those different expertise together. Otherwise we wouldn't have gotten this project off the ground.

Jordan Eamer

I think part of it, too, is just the expansion of our networks as well. I hadn't worked with Nova Scotia Community College prior to starting with Parks. And making those connections and the incredible resources there, but also bringing all of my connections from NRCan from past academic colleagues. I'm a science adviser with the Sable Island Institute. And that's one link we have between Parks and NRCan as well. And so bringing this whole network of researchers together, all bringing different things to the table, it really helps these broad research projects come together. I should also add that Dan always makes me get more than one data point. His statistical background... I can't just go and say: "Well, I see that thing there. So that must be how it is." So we work together well that way.

Barb Ustina

So based on your observations, the island is receding. I don't know if that's the word you use for it. But is it possible that one day the island will disappear? Like the question was asked, like a hundred years ago, 150 years ago. Are we still asking that same question?

Jordan Eamer

Yes, sure. Absolutely. So we were able to do ... it's almost a shame to call it a model. But we were able to sort of look ahead about 20 years with this analysis. And it does show a pretty significant recession in parts of the island in terms of the coast. But even 20 years into the future, I was surprised. When you live out there, and Dan can speak to this, too. It does sometimes feel like when it's a really big storm and it's coming at you from both coasts, it feels like the island is very small. And it feels like there's just no way it's going to stick around forever. But the results of this analysis anyway, did kind of show that, yes, the changes are real and they're significant in places. But there's lots of time here, too. And the island has been around for a long, long time. And so we've got some time to figure it out. But yeah, it's still an open-ended question as to what the overall trajectory is. And the thing we don't know, too, is what the island chain will look like in a in a scenario with accelerated sea level rise. We only know what we found up until this point. So with sea level rise increasing the rate over the next 100 years — that might play a very different role in how the island falls.

Dan Kehler

I would add to that, Jordan, that in many people's minds, the island is this curious mix of fragility and also resilience. So we see the effects of a single storm of it on the island. You think, how can that happen? And what does that mean for the future of the island? And what this project helped us do is to sort of take away those small episodic events and then look at what the long-term process has been over those 60 years. And from the national park perspective, it influences all the work that we do. It influences not just how species can persist in this environment, but also how the humans can persist. So what is the future and the fate of the site where we have infrastructure on the island, which we need to maintain in order to welcome visitors and to protect the island? It affects our ability to have visitors come to the island because the runway itself is on the beach. And so the beach is changing. So it's important for us to know how it's changing in order to understand whether we can continue to maintain and operate this place as we have in the recent past.

Joel Houle

That's really interesting. I never thought about the runway. Yeah, like, how do you land on sand? So, guys, if people would like to know more about the work that you do, or about Sable Island, are there any resources available online, like websites or social media accounts to follow?

Dan Kehler

Oh yes! We at Sable Island National Park Reserve, maintain both a website and a Facebook page. But there are many other resources beyond the National Park Reserve, including a great website produced by the Sable Island Institute, and there's a website by The Friends of Sable Island, all of which have great information about that place.

Jordan Eamer

Yeah, and I'm on Twitter. I just started it last year. It's got two tweets I think. So wait for that third! But, you know, there's also the Geological Survey of Canada at NRCan. They do a lot of their stuff through Twitter as well. So I think that's usually the more like cutting edge of what's coming out from those venues.

Joel Houle

Sounds good. We'll put the links in the description of the podcast. Make sure you subscribe to see Jordan's third tweet. Jordan and Dan, thank you so much for coming and chatting with us today.

Dan Kehler

Thank you so much!

Jordan Eamer

A lot of fun!

Joel Houle

That was a really fun interview! Jordan and Dan seem like the kind of people you'd want to be stuck on an island in the middle of the Atlantic Ocean with, right?

Barb Ustina

Yeah, no kidding. Now, maybe we will make it out there one day. Maybe we can put a bug in their ear that, you know, Simply Science can go out there and shoot a video with them some day or something like that would be amazing!

Joel Houle

Yeah. I mean, right now, during the quarantine, I'd settle for getting out of the house. But, you know, blue sky, I would love to go to Sable Island. It sounds absolutely amazing.

Barb Ustina

I know! Just goes to show that it's part of our amazing country, too, like from coast to coast. So many different places to go. I just wanted to mention before we sign off that Jordan and Dan, they're not working in isolation. They want to make sure that everybody knows that they're sort of continuing that long research tradition in a way. And they're building on a large body of scientific knowledge that's been gathered before them over the course of decades and centuries, really, by a wide range of scientists, naturalists and enthusiasts, including NRCan geoscientists and other federal government department research teams.

Joel Houle

So if our audience wants to know more about the work that's been done, we have some links in the episode description. We have information on Sable Island itself as well as the work that's being done by both departments. So check out those links. If you like this episode, feel free to share it with your friends. And if you share over Twitter, make sure to tag us. There's @NRCanScience for our Simply Science account. And you can always tweet at us directly. I'm @JoelScience...

Barb Ustina

And I'm @SimplyScienceB. That's the letter B. And I might remind everyone that Simply Science also has a website and a YouTube channel, which you should check out. We have in-depth articles of interest and videos that showcase the fascinating scientific work that we do at Natural Resources Canada. And this is just a taste of it today. And you can find those links in the episode description as well. Social media channels too.

Joel Houle

Thank you, Barb! And thank you so much, everyone, for listening. We'll see you in the next episode.

Barb Ustina

See you later!

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