#5 - Back from the field and lots to report!

Hi Everybody,

We're back from the field and we found lots of mummified seals! Over 300, in fact, and about 30 penguins just in our 3 weeks this season. However there must be thousands out there either buried, trapped under glaciers, or in more remote areas we couldn't get to. There's a bit too much to tell you all about in one email so I'll split up everything into 9 emails based on the most exciting and interesting parts of trip, maybe sending one a day for the next week or so. I'll do my best to show you all a bit about camp life, the natural history of the Dry Valleys, the seal-climate science, and working in one of the most remote regions in the world. Also at the end of this email I'll include a brief mention of what our project is all about from the UCSC PBSci newsletter for those who might want a general overview of the whole project. Without further ado...

Lower Wright Valley: Overview, Camp Put in and our First Foray into the Valleys

Since our primary objectives were to find as many mummified seals and seal bones as possible in the limited field time we had, we spent our time in places that seemed to have the densest concentration of seals. We spent the first half of our trip camped in Wright Valley and the second in Marshall Valley, which just south of what the map below shows. Throughout our field time we took many day trips to different valleys, along the coast, and to some dry spots farther to the north. Our camp moves and day trips were facilitated by helicopter, without which we'd be unable to cover nearly as much territory as we did!

In the lower right, you can see McMurdo station where we flew from for about a 40 minute trip to the east end of Wright Valley, and our sling load dropped off shortly thereafter. We managed to set up our camp shortly into the afternoon, so we could go for a hike and take a look for our departed seal friends in the same day. We were camped near the "ll" in Wright Valley. 

  

Upper Left- One of three Scott Tents for sleeping. In the Background you can see a roughly Miocene aged river spur that hadn't been eroded by glaciers since they didn't make it that far into the eastern edge of the valley. The river used to flow to the ocean, but uplift now forces glacial melt to flow in the opposite direction toward a depression now filled by Lake Vanda in Upper Wright Valley. Upper Right - The Wilson Piedmont and Lake Brownworth, blocking Wright Valley from the coast of the Ross Sea. Lower Left - The edge of the Wilson Piedmont (a massive glacier that cuts Wright valley off from the ocean,) about an hour to the east of our camp. Notice the sand dunes at the base of the glacier, Katabatic winds that blow out from the interior of the Antarctic continent are funneled through the valley and get caught at the wall of ice formed by the Wilson Piedmont. Meltwater forms Lake Brownworth in the right side of the image, which empties into the Onyx River, the largest and longest river in Antarctica, though not really comparable to the Amazon. Lower Right - Looking up at Clark Glacier, just north of our camp (the "ll" in Wright Valley on the map). I mostly just included this picture to show that I likely had a better lunch spot than you did in early January.

 

Left- Admiring the Wilson Piedmont. Right - Another view of the Wilson Piedmont

 

Left - Passing by a frost crack measurement experiment started in 1960, heading west from our camp. Right - Scott sampling a mummified seal.

You may have noticed that I mentioned the Wilson Piedmont blocks Wright Valley from the ocean. This means that many of the seals had to climb over this glacier to get into the valley, where many of them ended crawling up even further inland. The main question people tend to ask about in our project is "Why?" but we can really only speculate why they crawled inland based on how we find them, and it's difficult if not impossible to get inside a mummy seal brain and figure out exactly why. The vast majority of the seals we found are juveniles, a number of them we noticed had bite marks or scars, perhaps they either got lost trying to navigate around the Ross Sea, or maybe they were escaping predators. It's hard to say for sure. 

 This concludes the first email. If you have any questions just let me know and I'll try to cover them in other emails later on. 

Cheers from McMurdo,

Jon

PS. Mom, if you'd like to forward these to Mr. Wille or other teachers who might be interested in hearing about this, feel free!

PPS. Here's that general overview written by Paul Koch, the PI on this project:

Paul Koch: Climate Change and the Dry Valley

We live on a planet where climate cycles between large extremes, from the mostly glacial climates that set in about four million years ago to the warm greenhouse climates that were more typical over most of the last 500 million years. By understanding how species adapted to climate change in the past, we may be able to predict how they’ll react to ongoing and future climate change. My research in Antarctica is designed to answer questions about the vulnerability of marine animals to polar warming. 

I’m working on these questions with colleagues from UCSC, the University of Maine, Durham University, and the University of Pisa. Our field project is focused on the Dry Valley Region along the coast of the Ross Sea. This extreme polar desert receives less than ten millimeters of precipitation in a typical year (though we got about three years worth in a day-long blizzard last February). The frigid, dry conditions are ideal for creating the object of our mission here – seal mummies. These seals clearly made a tactical error, wandering up to 100 kilometers inland, before they succumbed to the inevitable (starvation, hypothermia). With only skuas (large seabirds) as scavengers, the seals are naturally freeze-dried. The mummies are ultimately destroyed by the fierce winds of the Dry Valleys, but many are over 1,000 years old.

The Ross Sea region was less icy in the not-so-distant past. Today ice shelves are frozen to the beaches along most of the coast, but several different lines of evidence suggest that the sea was lapping on those beaches just 1,000 years ago. This environmental change allowed the Ross Sea to sustain wildlife that is rare on the coast today. For instance, we have found fur, bones, and mummies of elephant seals along the central and southern coast of the Ross Sea, and our study of ancient DNA indicates that they came from a huge population of seals that collapsed about 1,000 years ago. Today, the area is populated only by species that have successfully adapted to the current icy conditions, such as the crabeater seal (Lobodon carcinophagus). The crabeater seal has been so successful that it is now the most abundant seal on Earth and one of the most abundant wild large mammals overall.

Because of human-induced warming, the Ross Sea may soon become less icy again. My colleagues and I are trying to squeeze a wealth of data from the dried out carcasses of crabeater seals and other marine mammals to understand how they dealt with a warmer past so we can predict how they’ll respond to a warmer future. We are using skeletal measurements to identify the species and age of the species, radiocarbon dating to determine when they lived and died, forensic chemistry to infer their diets, migratory behavior, and clues about their environments, and ancient DNA to reconstruct seal populations and evolutionary trends. We hope the deeper understanding of seal behavior gleaned from fossils will be useful to wildlife biologists as they work to conserve these iconic species.