Posts from Antarctica: Staying Safe in the Field Part 2 – Safety and Crevasse Rescue Trainings

kalley November 30, 2019 2:35 am

The United States Antarctic Program (USAP) primarily exists to support scientific research in Antarctica. In order to provide that support, one of their most important functions is to ensure the safety of all personnel involved in the research. Much of our time at McMurdo has been spent doing trainings to get us oriented to the station, our environment, and the equipment we’ll be using. I’ve had general trainings on operating NSF’s light vehicles, waste management, medical facilities, fire prevention and response, harassment, and environmental protection. I’ve also done field-oriented trainings on understanding the contents of our survival bags (we carry these with us at all times off station or out of camp; they include things like emergency tents and sleeping bags, a stove, fuel, and food), recognizing signs of hypothermia and frostbite, assessing and managing risk, and driving snowmobiles. We also do trainings that are specific to where we’re headed in the field. In our case, that includes crevasse rescue training.

Our team is headed (as soon as we can get out of McMurdo) for two camps in the deep field, both of which are on ice shelves. Ice shelves are the floating extensions of the ice sheet: they’re connected to and flowing with the ice on the continent, but they are also truly floating on the ocean, going up and down with the tides. Since the undersides of ice shelves are sitting in water, there is virtually no friction at their bases slowing them down, so ice tends to speed up when it flows into an ice shelf. Any time ice speeds up, goes around a bend, crosses a big change in elevation, or hits a bump in the bedrock, it tends to crack, forming crevasses. These crevasses can be hundreds of feet deep and are often hidden by a fragile layer of snow known as a “snow bridge,” which can be very difficult to spot. If you unknowingly cross a snow bridge, it may collapse under your weight, dropping you into the crevasse.

We plan to do our best to avoid crevasses in the first place. Our team includes two professional field guides, Cece and Blair, who will scout all our sites and travel routes before we use them for science. That has been done as much as possible already using high-resolution satellite imagery. Once our advance team gets to WAIS Divide, they will go out on one or two reconnaissance (“recce”) flights to inspect our sites from the air. If it’s safe, the pilot will land, and Cece, Blair, and our team member Martin will run radar to double-check that there aren’t bottom crevasses in our camp location that could disrupt the drilling operations. Once the team gets to the field, Cece and Blair will travel the routes we plan to take and use flags to mark areas that are safe and indicate hazards to avoid.

Proving routes in this way is incredibly valuable and raises our margin of safety greatly, but we will be in a rapidly changing environment, and new crevasses can open or be uncovered during our time in the field. We will ensure that our campsite is in a spot that is really, really safe, so there’s no problem walking around there without extra precautions. Anytime we move outside of camp, however, we will used roped travel, whether that’s on a snowmobile, on foot, or by ski. In this system, everyone wears climbing harnesses, and attaches their harnesses to knots in a long rope connecting the party. Each member of the team is spaced out a good ways – our foot/ski ropes will have a 15-meter spacing between people, and the snowmobile rope teams will have a longer spacing. The idea is that if someone breaks through a snow bridge, the other people on the team will be able to catch them on the rope. When we did our crevasse rescue training in the field last week, part of what we did was learn how to properly lay out ropes for travel, tie the right knots, and clip in securely.

Blair sets up knots in one of the ropes that we will use in the field for roped snowmobile travel

Once a person falls into a crevasse and is caught by the rope, there are lots of options for getting that person out. Assuming the person is conscious and can communicate, the team can start by just trying to walk away from the crevasse and haul them out. It’s really important to communicate, however, because sometimes crevasses have overhangs that the person can get crushed under as the team hauls them out. If the person can’t communicate (perhaps they’re just too far away to hear), or if the team isn’t strong enough or the footing not solid enough to haul the person out by walking, there are a bunch of options.

First, the person in the crevasse will be connected to the rope with two smaller looped cords, attached with a knot called a Prusik hitch. This hitch can slide up the rope easily when not under tension, but holds tight when weighted. One of those Prusiks is attached to the waist of the harness, and the other is attached beneath it and has another loop tied in it that goes around the foot. If the person in the crevasse is able, they will stand up on the foot Prusik and move the waist Prusik up the rope. Then they put their weight on the waist Prusik and move the foot Prusik up, continuing that way until they can wriggle up over the edge of the crevasse.

Me practicing using Prusik hitches to move up and down a rope during our indoor rope training, while field guide Blair watches and gives me instructions

If the person in the crevasse is unconscious or unable to move up the rope on their own, the team up above needs to set up a pulley system to get them to the top. The first thing that has to be done is to make it so the team isn’t having to use their weight to keep the person in the crevasse from falling. This involves digging a snow anchor, in which some sort of stable object, such as a shovel, ice axe, or a piece of metal that has been designed to be a strong snow anchor, is buried a foot or two deep in the snow and rigged so it can be attached to the climbing rope that the person in the crevasse is on. Once the snow anchor has the person’s weight, the rest of the rope team have more freedom to move around to build a pulley system, get another team member down into the crevasse to help the person if necessary, lower another rope to the person in the crevasse, etc. Exactly which technique is used depends strongly on the individual situation. Fortunately, either Cece or Blair will be with every team working outside of camp, so they will be there to make technical decisions and give directions if a crevasse rescue is necessary.

Blair (right) helps Atsu and Doug rig a pulley system that can be used to get a teammate out of a crevasse

These techniques were all brand new to me. We practiced much of the rope work indoors first (I arrived in McMurdo at 3:30 in the morning and indoor rope training started that day at 8 am. I was a bit late, but I did make it!). The day after our indoor training, we spent the whole day out on the ice shelf where a bulldozer had been used to dig a large simulated crevasse. It was really valuable to practice the same skills we learned indoors in an outdoor setting – everything gets harder when you’re wearing gloves and your rope is digging into the snow.

Cece (top) helps Ted with some advanced crevasse rescue techniques in the bulldozed “crevasse”

We don’t expect to need any of our crevasse rescue skills; we intend to avoid crevasses in the first place. But we also need to be prepared in case we need to act in an emergency situation!

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Posts from Antarctica: Staying Safe in the Field Part 1 – Staying Warm

kalley November 28, 2019 1:01 am

Before I dive into the current topic, a quick update on our logistics: Our advance team was supposed to fly out on Wednesday, November 27, but between bad weather at WAIS Divide and the holiday weekend, they are now officially delayed until Monday, December 2nd. Once they get out to the camp at WAIS Divide, they will run reconnaissance flights (“recce flights”) from there to scout the site and start putting in our first field camp on Thwaites Glacier. The rest of our team will follow to get in position at WAIS Divide, probably in stages. My guess is I’ll be listed on a flight that’s aiming to leave for WAIS Divide sometime in the middle of next week; it’s highly unlikely that we’d leave as early as Monday (the day all of us who aren’t on the advance team were originally hoping to fly), and we could get out as late as who-knows-when, depending on weather. That’s all to say: Expect several blog posts over the next few days, since I should still have relatively reliable internet as long as we’re in McMurdo. Things will get much spottier and less verbose (and with fewer pictures) once we move to the deep field!

Now on to the topic at hand: staying safe in the field…

Antarctica is not a forgiving continent. Staying safe in the field requires careful advance planning, a detailed understanding of the terrain, constant vigilance to catch changes in surface conditions, close attention to weather observations, and plans for every contingency. The mortality rate of Antarctica’s earliest visitors was harrowingly high, but modern scientific expeditions are very safe. However, that safety is only achieved by hard work before and during the field season.

Our time in McMurdo has two main purposes: prepare our science and cargo for the field, and prepare ourselves for the field. Preparing our science and cargo for the field would make for a pretty mundane blog post (it involves many hours of testing, labeling, spreadsheets, and packing), but I thought you might find it interesting to know how we prepare ourselves for the field. This is a big topic, so this will be the first in a series of posts on staying safe in the field (which may or may not be posted consecutively). I’ll talk here about staying warm, and in later posts I’ll cover how we train for the field and what sort of communications and emergency responses we have available.

One of the most important aspects of staying safe in the field is staying warm. Everyone who comes to Antarctica with the US Antarctic Program (USAP) is directed to bring our own base layers (the technical name for long underwear), which are typically wool, silk, or synthetic lightweight layers that are worn as the first layer beneath many. These layers are good at wicking moisture away from the skin, keeping us relatively dry and warm. We also have to bring our own socks. I like to wear a pair of silk liner socks under heavyweight wool socks.

After base layers, we move onto mid-layers. USAP provides some of these at the Clothing Distribution Center (CDC) in Christchurch, and typically people bring some of their own, as well. I usually wear a pair of fleece pants over my base layer, as well as one or two light-to-midweight fleece tops. Sometimes I’ll swap a fleece for a lightweight down jacket. Whenever possible I choose mid-layers that have hoods, as these can be pulled over or under hats while keeping drafts off my neck.

Wearing the USAP-issued parka, “Big Red.”

USAP supplies most of our outerwear. We’re provided with seriously warm boots, waterproof snow pants, and the iconic big, cozy parka known as “Big Red.” They also provide us with thin liner gloves, insulated leather work gloves, mittens, goggles, a hat, a balaclava, and a neck gaiter. I was pleased to note that most of the issued gear fits me fairly well; in the past, USAP gear was limited to men’s sizes, and women (especially small women) often found outfitting at the CDC to be challenging. My waterproof pants and fleece mid-layer are definitely a bit big but wearable, and the proportions of Big Red make working in the parka difficult for just about everyone, but especially for smaller individuals (if it’s not too terribly cold, I’ll switch to wearing a smaller down coat I brought myself; many people bring their own outerwear that’s a little easier to work in) . The biggest problem for me is that the smallest work glove size is too large for me, making working in those nearly impossible. Fortunately I brought a few pairs of my own gloves.

I like to wear silk liner gloves under relatively thin work gloves, and I keep mittens in my pockets to warm up my hands when I don’t need the dexterity of gloves. I wear a neck gaiter – just a wide, stretchy loop of fabric that goes around my neck, like a compact scarf – which I can pull up over my mouth and nose when the cold or wind are too much. I tend to wear one relatively lightweight hat and use my hoods for extra warmth. With 24-hour sunlight and a highly reflective snow surface, eye protection is very, very important; I have a pair of glacier glasses with adaptive polarized lenses that do a really excellent job toning down the brightness, and I also plan to always carry my USAP-issued tinted goggles that can cover more of the area around my eyes if it is too cold or windy.

All the clothing I’ll wear on a typical day in the field

Having the right clothing is vital to staying warm, but just wearing the gear is not enough. It’s really important to dress in layers and to proactively add and remove layers as needed. Just as getting too cold is a problem, getting too warm and sweaty makes your clothing damp, cooling things down quickly if you stop moving or if the temperature drops. It takes some practice to figure out which layers work best for you and for the weather conditions, and adjustments have to be made throughout the day as weather changes. Rather than adding more clothing to get warmer, sometimes it’s more important to start moving, or to eat or drink something calorie-dense; your body can’t produce enough heat without calories for energy, and typically it’s important to eat many more calories than normal to keep your body warm in a cold environment (i.e. we eat a LOT of chocolate). When needed, we also use external heat sources; in particular, we sometimes use instant hand and toe warmers in our gloves and boots, and will fill our thermoses and Nalgene water bottles with boiling water for hot drinks and for hot water bottles that act as a temporary heat source.

USAP also provides our camping equipment. We have several types of tents, which I hope to talk about in later posts. One of the most important aspects of staying warm at night is having insulation between the ground and your sleeping bag. Sleeping bags keep you warm primarily through the insulating effects of air trapped by the down or synthetic insulation. Underneath your body, the air is squished out of the sleeping bag, so that’s often where the most heat is lost. USAP provides both a foam sleeping mat and an inflatable sleeping mat, which are stacked on top of each other under the sleeping bag. The sleeping bags themselves are large and warm, and we typically use a fleece or synthetic sleeping bag liner or two to fill in some of the space inside the sleeping bag, or an extra bag over the top to make the whole system warmer. Depending on the temperature and the warmth of the sleeping bag and the temperature of the night, I might sleep in just my base layers, or I may add layers as necessary. I also often wear booties with down insulation in the tent and in in my sleeping bag to keep my feet warm (hot water bottles help with this, too!). We use “mummy bags,” which are sleeping bags that are narrower near the feet to keep them warmer, and have a hood that can be cinched in on cold nights so only your nose sticks out.

The result of all this is that, although it’s common to get cold from time to time throughout the day, there’s usually no excuse for staying cold. You add layers, use external heat sources, eat something, and start moving. It’s a lot of effort and requires a lot of practice and management, but we’re typically relatively warm and comfortable in the field.

Happy Thanksgiving to all of you back in the US!

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Posts from Antarctica: Antarctic transportation

kalley November 26, 2019 7:37 pm

Antarctica is arguably the world’s most remote landmass. There are no human native Antarcticans; by the time homo sapiens emerged, Antarctica had long-since drifted south, been isolated by the Southern Ocean, and grown an ice sheet. Captain James Cook came close to Antarctica in the late 1700s, but did not catch sight of the ice sheet; it wasn’t until the 1800s that explorers and sealers began to map the waters around Antarctica and first set foot on the continent.

Although our transportation technologies have developed significantly in the past two centuries, Antarctica remains a remote and difficult place to get to. It’s also difficult to travel within Antarctica. I thought I’d tell you a bit about my journey down here, and share a few pictures of some of the vehicles that are used at McMurdo and across Antarctica.

The LC-130 on skis that brought us to McMurdo

Most trips to Antarctica start in the familiar commercial airline system. I flew from Cleveland to Houston, and after a long layover, from Houston to Auckland on the North Island of New Zealand. In Auckland I retrieved my luggage and cleared customs before checking back in for one more short flight to Christchurch on the South Island. National Science Foundation (NSF) representatives met me and a dozen other Antarctic travelers at the airport, gave us hotel and scheduling information, and put us on a shuttle. After nearly 40 hours of travel, I was very grateful to have a day or two to adjust to the new time zone (Christchurch is 18 hours ahead of US eastern time; McMurdo, and all US field teams, keep Christchurch time while in Antarctica in the summer).

The next morning we were taken to the NSF Clothing Distribution Center (CDC), where we were issued our Extreme Cold Weather (ECW) gear. (I hope to talk more about clothing and staying warm in Antarctica in a future post.) We were told that both the C-17s, flown by the 109th Airlift Wing of the New York National Guard to move people and cargo to polar regions, were out of commission, so there was a 99% chance we wouldn’t be flying to the ice the next day. We all settled in to enjoy Christchurch for a couple days. I highly recommend the botanic gardens, if you ever have the chance to visit.

Inside the LC-130 on the way to McMurdo

At breakfast the next morning I was surprised with the news that a flight was going that evening, so I packed up my gear, checked out of the hotel, and enjoyed one more beautiful warm day in the city. That afternoon a shuttle took us back to the CDC, where we checked in all our gear and boarded one of the National Guard’s LC-130s. These are also used to move people and cargo to McMurdo, but are much slower, smaller, and louder than the C-17s, so they’re not the most desirable aircraft. There are only 10 LC-130s in the world, and each are equipped with huge retractable skis, so they can land on both conventional and snow runways. Our flight to McMurdo left around 7 pm and took 8 hours (it takes about 5 hours on a C-17). We were very tired when we landed in McMurdo around 3 in the morning. 24-hour sunlight this time of year means that we had no trouble finding our shuttles, which took us to McMurdo station and our dorm rooms for a few hours of sleep.

I’ll talk in more detail about the trainings we’ve had in a separate post, but along with the C-130s and C-17s, I wanted to mention a few more methods of transportation that are used in McMurdo and on the ice sheet.

A big-wheeled van common in McMurdo

To get around town (McMurdo has a population of approximately 1,000 in the summer, so it really is a town!), vans and trucks modified with very large wheels are used. McMurdo is full of volcanically-derived dust and mud that tend to make everything dirty and necessitate big wheels. Large-wheeled vehicles are also used to distribute pressure from the vehicles that drive out onto the seasonal sea ice and the permanent ice shelves in the area. Vehicles that carry a lot of gear often have tracks rather than wheels for extra traction.

The tracked Hägglund vehicle used to haul our gear

Two of the most unusual vehicles I’ve encountered are the Hägglund and the Delta. The Hägglund is a Swedish vehicle, first developed in the 70s, which has two compartments on tracks and can be used for hauling people and gear. If you ever visit the International Antarctic Center in Christchurch, you can take a ride in a Hägglund. We used them on our outdoor crevasse rescue training day and our overnight camp shakedown (more posts to come!) to carry gear out to our sites on the ice shelf.

The low-pressure Delta vehicle that brought us to and from our overnight camp on the McMurdo Ice Shelf

The Delta is a low-pressure vehicle originally designed for use in oil fields on the delicate Arctic tundra. Although these vehicles look anything but delicate, the huge wheels spread out their weight so that no single point beneath them is subjected to damaging pressures, making them actually very gentle on the surfaces they drive on. We rode in a Delta to and from our overnight shakedown out on the ice shelf a couple days ago.

A snowmobile similar to the ones that we will use at our field sites

Over the next week or two, our team will begin moving to the deep field. If the weather holds, our advance team (I’m on the later team) will fly tomorrow to a camp called WAIS Divide on an LC-130. From there they will move to smaller Twin Otter aircraft to begin setting up camp on the floating tongue of Thwaites Glacier. Setting up a large polar science camp, with heavy tents, generators, drilling equipment, safety gear, etc. takes many flights and many days of work. While on the ice sheet, we will move by snowmobile, ski, and on foot to manage logistics and carry out our research.

Reminders of the remoteness and harshness of this continent are constant in McMurdo. The unusual vehicles are one of those reminders. It’s worth remembering that the science we do here is only possible thanks to the hard work of hundreds of people – the Air National Guard, pilots, heavy equipment operators, fuel specialists, firemen, and many more that work very hard to deliver and manage the equipment we need.

Our team riding in the back of the Delta vehicle

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Posts from Antarctica: Intro to the International Thwaites Glacier Collaboration and the TARSAN project

kalley November 22, 2019 7:22 pm


Greetings from McMurdo Station, Antarctica! For those of you who don’t know me, my name is Karen Alley and I’m a visiting assistant professor in the College of Wooster Department of Earth Sciences. I’m a glaciologist and a remote sensor, which means that I study ice sheets and glaciers mainly using satellite imagery. Most of my work has focused on the interactions between the floating parts of ice sheets, known as ice shelves, and the ocean beneath.

I’m in Antarctica as part of the International Thwaites Glacier Collaboration (ITGC; www.thwaitesglacier.org). Our team is TARSAN (Thwaites and Amundsen Regional Survey and Network). In a couple weeks we’ll be heading out first to the floating tongue of Thwaites Glacier and then to the Dotson Ice Shelf. I should be able to share a few blog posts while I’m at McMurdo, and I might even be able to get some text out from the deep field, if our satellite uplink works. I hope to share with you information about our research and about living and working in Antarctica. If I can’t get posts through from the deep field, I’ll at least be able to share some info when I return in February.

For now, I wanted to provide an introduction to the ITGC and our team’s role in that project.

Let’s start with the big picture. We study the world’s ice sheets and glaciers for many reasons, but one of the most globally important reasons is to understand rates of sea-level rise. Greenland holds about 23 feet of equivalent sea level. That means that if all of the ice in Greenland melted, every ocean in the world would rise 23 feet. I spend my life studying this stuff, and I still have a difficult time imagining those numbers. Just Greenland, a relatively small landmass, has enough ice piled on top to raise every single bit of ocean in the world 23 feet.

Antarctica, on the other hand, holds about 187 feet of equivalent sea level.

Now, that being said, we’re not in any danger of melting all the ice in Greenland and Antarctica, so we’re not worried about 200+ feet of sea-level rise coming anytime soon. However, those very large numbers mean that melting even a small percentage of Greenland and Antarctica has big consequences, since millions of people in the world live within just a few feet of sea level.

So, to understand sea-level rise, we have to understand what the ice sheets are going to do as the world warms. Since the ice sheets are huge, we focus on the parts of the ice sheets that are most likely to change and that hold enough ice to significantly impact global sea-level. Thwaites Glacier is at the top of the list.

Thwaites Glacier, which is the name of a fast-flowing, Florida-sized portion of West Antarctica that dumps a whole lot of ice into the ocean, is arguably the most important glacier in Antarctica. It is thinning, retreating, and increasing ice discharge rapidly, and it holds back much of the ice in West Antarctica. (Antarctica is often divided up into West Antarctica, East Antarctica, and the Antarctic Peninsula. West Antarctica is the piece of the ice sheet that sits deepest below sea level, which makes it most likely to respond to rising ocean temperatures.)

Recent work (e.g. this paper or this one) suggests that Thwaites Glacier isn’t stable. Over the next few hundred years, it is likely to melt back and break apart piece by piece, releasing west Antarctica’s ice and raising sea levels by 10 feet or so. As a scientific community, we need to find out whether it’s true that Thwaites is slowly collapsing, estimate how much and how fast sea-level rise will occur, and constrain the processes leading to this collapse in order to predict how similar patterns might progress in other parts of Antarctica and Greenland. The ITGC is an effort between the US and the UK to answer some of these pressing questions. Eight teams are examining ice flow patterns, sediment cores that tell us the history of the glacier, ocean characteristics, sub-ice-shelf bed topography, grounding-line (where the glacier goes from sitting on land to floating) dynamics, basal melt rates, surface accumulation patterns, computer models predicting the glacier’s future, and more.

Our team is split into two groups. One group is doing ship-based measurements of ocean conditions near Thwaites. The group I’m in will be on the floating part of Thwaites Glacier, and later on the nearby Dotson Ice Shelf. We intend to use seismic surveys to study the ocean and the bed beneath the floating ice shelves, radar to look at details of accumulation and change within the ice itself, and a hot-water drill to drill through the ice shelves and place instruments in the ocean underneath. We want to know more about the details of the interactions between the ice shelves and the ocean beneath, and to pinpoint the circulation patterns that are leading to melting at Thwaites. Much of the relatively warm water reaching the Thwaites grounding line may travel beneath Dotson, so our group and the ship-based group will provide a slightly larger context for understanding changes at Thwaites.

For now we’re completing safety trainings and equipment preparation at McMurdo, and crossing our fingers that weather and logistics hold to allow us to collect plenty of data. I’ll share some info about those trainings and preparations in a later post or two!

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New paper: Early Silurian recovery of Baltica crinoids following the end-Ordovician extinctions (Llandovery, Estonia)

Mark Wilson November 16, 2019 6:27 pm

It has been an absolute delight to work with the crinoid master Bill Ausich of The Ohio State University. He is not only one of the world’s top paleontologists, he’s a great guy. Bill taught me all I know about Paleozoic crinoids and their complex systematics. Last week our latest paper appeared on Silurian crinoids in Estonia, with the perceptive and observant Ursula Toom (Department of Geology, Tallin University of Technology) as our co-author. Here’s the abstract from the Journal of Paleontology—

“Three new Llandovery (early Silurian) crinoids from Estonia provide an improved understanding of the paleogeographic aspects of the crinoid diversification following the end-Ordovician extinctions. The new taxa are Euspirocrinus hintsae new species (Rhuddanian eucladid), Oepikicrinus perensae new genus new species (Aeronian camerate), and Rozhnovicrinus isakarae new genus new species (Aeronian eucladid). This brings the total of described Llandovery crinoids in Estonia to eight nominal species and a further three taxa in open nomenclature. The Rhuddanian radiation in Baltica mirrored that on Laurentia and Avalonia and was dominated by Ordovician clades that continued to diversify during the Silurian. Known Aeronian crinoids from Estonia continue these clades, whereas new clades diversified on Laurentia and Avalonia. However, by the Wenlock, a largely cosmopolitan fauna existed on Laurentia, Avalonia, and Baltica.”

Bill and I visited Estonia in the summer of 2018 to do this work, which took place primarily in Tartu and Tallin. We had a wonderful time with our Estonian friends. This particular project involved the description of new Silurian crinoids to help plot crinoid recovery and diversification after the end-Ordovician mass extinctions.

One of the new crinoids is shown above. It is Oepikicrinus perensae n. gen. n. sp., a new eucamerate from the Llandovery. The genus is named after Armin Öpik (1898–1983), an epic Estonian paleontologist. The species name recognizes Helle Perens, an expert Estonia geologist. The figure particulars: (1) lateral view of two paratypes, TUG 999-1-1 and 999-1-2; (2) lateral view of partially disarticulated paratype GIT 405-254-3; (3) lateral view of holotype GIT 405-254-1, with complete arms, also note long pinnules; (4) lateral view of compacted paratype GIT 405-254-2, with proximal arms. Scale bars = 1.0 mm (2); 2.5 mm (1, 3, 4).

The above plate shows the other two new crinoids. Rozhnovicrinus isakarae n. gen. n. sp., a new eucladid, is named after the prominent Russian paleontologist Sergei V. Rohznov and our Estonian friend and paleontological colleague Mare Isakar. Euspirocrinus hintsae n. sp., another new eucladid, is named for Linda Hints, an Estonian paleontologist who found the best specimen. The figure details: Rozhnovicrinus isakarae n. gen. n. sp.: (1) crown with damaged aboral cup, paratype TUG 1329-14-1; (2) two specimens, the larger with only an impression of the aboral cup is paratype GIT 405-252-1, and the smaller complete specimen is holotype GIT 405-252-2; (3) D-ray lateral view of aboral cup of paratype GIT 405-252-1; (4) enlargement of holotype GIT 405-252-2 and arms of paratype GIT 405-252-1 (see Fig. 5.2); (5, 6) paratype TUG 1329-14-4: (5) aboral cup and proximal arms; (6) enlargement of aboral cup; (7) Euspirocrinus hintsae n. sp., holotype GIT 405-256, note distal coiling of arms. Scale bars = 2.5 mm (1, 3–6); 5.0 mm (2, 7).

This all looks very esoteric when I write these highlights, but it was a challenging and fun project. This work is an example of systematics used to address paleoecological, evolutionary and biogeographic questions. It also represents the continuing work of a diverse, international team.

My colleagues Bill Ausich and Ursula Toom in Tallin, Estonia (summer 2018).

Reference:

Ausich, W.I., Wilson, M.A., & Toom, U. 2020. Early Silurian recovery of Baltica crinoids following the end-Ordovician extinctions (Llandovery, Estonia). Journal of Paleontology, DOI: https://doi.org/10.1017/jpa.2019.89

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Wooster Records Wettest Year on Record

acrawford October 13, 2019 8:13 pm

Last year around this time, I reported on this blog that Wooster had just completed its third wettest year on record. A year later, the “wettest year” record has been broken. With continuous record-keeping beginning in 1900 at the OARDC weather station, the 1901 water year (Oct 1900 through Sep 1901) is the first full year, and 2019 is the 119th year on record. Amazingly, this was the wettest year ever recorded for Wooster. Here is an updated graph of the annual precipitation in Wooster with “line of best fit” and a more detailed curve. The black dot at the end of the time series is water year 2019. At 56.3 inches, it beat out the previous record of 51.0 inches set in 2004 by 6% — a large margin! Note that although, there has been a long-term increase in annual precipitation at Wooster, this year was so far above the trend line that it’s likely we’ll drop back down to around 42 inches next year.

The reason for this record was primarily because of an exceptionally wet period from May through August, peaking with a July in which we experienced about twice as much precipitation as normal. Late spring to early summer is usually our wetter season, but this year the summer storms were dramatic. However, as shown in the plot below, every month except September yielded above-average precipitation. (The green bars are the total precipitation in 2019 for each month; the blue dots are the average, and the black whiskers are the standard deviation.) In fact, the record was broken in August!

Finally, it’s worth noting that the maximum daily precipitation was 4.22 inches recorded July 22. That ranks 5th highest all-time in Wooster for daily precipitation. Only two days have ever had over 5 inches — September 14, 1979 and the infamous flood of July 5, 1969. (Note, because of when precipitation is recorded, much of the precipitation really fell on the 21st, 13th, and 4th, respectively.)

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A new paper on the future of Antarctica’s Ice Shelves

kalley October 9, 2019 3:41 pm

Our group published a new paper today in Science Advances, which suggests that ice-flow models that predict future sea-level rise are missing an important process: Basal channels, which are “upside-down rivers” of buoyant water flowing along the undersides of ice shelves, have formed at the margins of some of Antarctica’s most important ice streams. For example, Pine Island Glacier, shown below in a 2007 NASA MODIS satellite image, has basal channels beneath both of its weak “shear-margins” (red dashed lines). We know warm water is flowing through these channels because they create open-water areas, called “polynyas,” at the ice-shelf edge. These channels are weakening the weakest areas of fast-flowing ice streams, making them more susceptible to ocean-driven break-up.

Check out Wooster’s press release here: https://news.wooster.edu/news/2019/10/wooster-professor-is-lead-author-in-new-study-on-antarctic-conditions-that-are-causing-sea-level-rise/

The full article is open-access and can be downloaded from Science Advances: https://advances.sciencemag.org/content/advances/5/10/eaax2215.full.pdf

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A new paper on a cryptic crustoid graptolite from the Middle Ordovician of Estonia

Mark Wilson October 7, 2019 4:04 pm

I have long enjoyed exploring the Ordovician and Silurian rocks of Estonia with my Estonian friend Olev Vinn. We have done a lot of work together, and Estonia continues to provide fascinating fossils for our studies. Our circle of paleontologists has expanded continually over the years in Estonia, including other Estonians, Brits and Americans (along with many Wooster students — search “Estonia” in this blog).

This latest paper, Vinn et al. (2019), is from a project Olev, Ursula Toom, and I pursued with a single specimen from the Middle Ordovician (Darriwilian) of Estonia. It analyzes the unusual preservation of crustoid graptolite (rather rare in its own right) preserved inside the gloomy hollow of a nautiloid shell (its conch). Here is the abstract:

“A light grey nautiloid conch has a dark brown colony attached to its internal surface. This colonial fossil resembles hederellids and bryozoans, but is in fact a crustoid graptolite (Hormograptus? sp.). The colony has been lithoimmured inside this nautiloid conch by early cementation. Crustoid graptolites were a part of the encrusting communities in the Middle Ordovician of Baltica, but their abundance among encrusters of biogenic substrates reached a peak in the middle Sandbian. The cryptic mode of life appeared very early in the evolution of the crustoids. The discovery of this crustoid graptolite in a nautiloid conch indicates that the Baltic Middle Ordovician cryptic communities were taxonomically more diverse than was known previously. The nautiloid conch studied is sparsely encrusted with an encrustation density that is similar to those of other Middle Ordovician cryptic surfaces described from Estonia.”

From figure 2: Hormograptid graptolites from the Ordovician of Estonia. A–C. Hormograptus? sp., attached to the internal surface of a nautiloid conch; Harku Quarry, Kunda Regional Stage (lowermost Darriwilian) (GIT 494-41-1). [Image C is at the top of this post.]

The unusual taphonomic pathway of this specimen was through lithoimmuration, in which early calcite cement essentially entombed the crustoid graptolite colony against the internal nautiloid shell surface. That shell was made of aragonite which quickly dissolved, leaving the base of the graptolite exposed for us. That was enough to make the identification and show a bit of cryptic niche space occupied in the Middle Ordovician.

Reference:

Vinn, O., Wilson, M.A. & Toom, U., 2019. A crustoid graptolite lithoimmured inside a Middle Ordovician nautiloid conch from northern Estonia. Annales Societatis Geologorum Poloniae, 89: doi: https://doi.org/10.14241/asgp.2019.17

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Wooster Geologists at the 2019 Annual Meeting of the Geological Society of America

Mark Wilson September 29, 2019 1:54 pm

Phoenix, Arizona — It was a small group of Wooster Geologists at the annual meeting of the GSA held in Phoenix last week. The very early date (about a month earlier than usual) and the consequently earlier abstract deadline reduced attendance overall, especially for those geologists who needed the summer to collect data (most of our Independent Study students). Wooster had only one student at the conference: the happy Evan Shadbolt (’20) pictured above. Evan and I presented a poster on research by Team Jurassic Utah. Since we did the fieldwork in March 2019, we could get our abstract completed by the early deadline.

Dr. Greg Wiles gave an oral presentation on Holocene Alpine glaciation in southern coastal Alaska with a group of Wooster student and staff co-authors representing the Wooster Tree Ring Lab.

I was very proud to be part of a poster presentation on the Middle Jurassic of Israel by Yael Leshno Afriat, a graduate student at Hebrew University in Jerusalem. It was a delight to see Yael again, and her poster brought back great memories of fieldwork in the Negev.

The GSA annual meeting is where the Paleontological Society has its own annual meeting. This year long-time friend of Wooster Geology Dr. Paul Taylor was awarded a Fellowship of the society. Richly deserved. Search this blog for “Paul Taylor” and you’ll see how important he has been to us for decades.

The annual Wooster alumni gathering was, like every other event at this meeting, unusually under-populated. Nevertheless it was a great group, and there were alumni there we hadn’t seen at this meeting before. The photograph is of those present at our traditional 8:00 pm Monday picture time. There were several other Wooster geologists at the meeting who could not make it to the event at this time.

Next year in Montréal! This meeting will have more reasonable dates: October 25-28, 2020.

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New Publications from the Tree Ring Lab

gwiles September 26, 2019 8:16 pm

Four new studies from the Wooster Tree Ring Lab have recently appeared in Ecology, Journal of Geophysical Research – Biosciences, The Holocene and Chemosphere.

Brian Buma lead the study published in Ecology that described the results of revisiting a classic ecological succession site in Glacier Bay National Park and Preserve. The article is titled: 100 years of primary succession highlights stochasticity and competition driving community establishment and stability. We blogged about some of the fieldwork for this study a few years ago here.

Abstract: The study of community succession is one of the oldest pursuits in ecology. Challenges remain in terms of evaluating the predictability of succession and the reliability of the chronosequence methods typically used to study community development. The research of William S. Cooper in Glacier Bay National Park is an early and well‐known example of successional ecology that provides a long‐term observational dataset to test hypotheses derived from space‐for‐time substitutions. It also provides a unique opportunity to explore the importance of historical contingencies and as an example of a revitalized historical study system. We test the textbook successional trajectory in Glacier Bay and evaluate long‐term plant community development via primary succession through extensive fieldwork, remote sensing, dendrochronological methods, and newly discovered data that fills in data gaps (1940’s to late 1980’s) in continuous measurement over 100+ years. To date, Cooper’s quadrats do not support the classic facilitation model of succession in which a sequence of species interacts to form predictable successional trajectories. Rather, stochastic early community assembly and subsequent inhibition have dominated; most species arrived shortly after deglaciation and have remained stable for 50+ years. Chronosequence studies assuming prior composition are thus questionable, as no predictable species sequence or timeline was observed. This underscores the significance of assumptions about early conditions in chronosequences and the need to defend such assumptions. Furthermore, this work brings a classic study system in ecology up to date via a plot size expansion, new baseline biogeochemical data, and spatial mapping for future researchers for its second century of observation.

Photo taken in the West Arm of Glacier Bay close to where the Cooper plots were “rediscovered”.

 

Dr. Ben Gaglioti (University of Alaska – Fairbanks)  just lead another innovative study. This time Ben has assembled a time series of traumatic resin ducts (TRDs) in mountain hemlock that  is a record of past winter conditions and the strength of the Aleutian Low. The article appeared in the Journal of Geophysical Research: Biogeosciences.

The study included tree-ring records from four wild outer coast sites along the the Gulf of Alaska. This is the first work to use these TRD features in tree-rings as a proxy for winter storminess.

a – The clearly-stressed trees used in this study. b – Careful observations and measurements from increment cores were taken to work out the timing of maximum wind stress and storminess. c, d –  Examples of Traumatic Resin Ducts in the tree rings.

Once assembled, the decadal variability of the winter time record was clearly related to the Pacific Decadal Oscillation (see below). This new record is the first of its kind and gives us a new record of wintertime variability from the North Pacific.

Figure above shows a frequency diagram TRDs compared with indices of winter Pacific decadal variability. The records compare favorably giving us confidence in this new proxy technique and Ben’s interpretations.

Ben used some new sites and some from  the archives of the Wooster Tree Ring Lab as part of this study and his new technique is one that the Wooster lab can adopt and learn as we continue to analyze new collections and re-analyze our past collections.

 

Rob Wilson (University of St. Andrews) lead a study from the Yukon. He used blue intensity tree-ring records from white spruce to improve dendroclimatic temperature reconstructions from the southern Yukon.

The study is titled: Improved dendroclimatic calibration using blue intensity in the southern Yukon. and the abstract reads like this: In north-western North America, the so-called divergence problem (DP) is expressed in tree ring width (RW) as an unstable temperature signal in recent decades. Maximum latewood density (MXD), from the same region, shows minimal evidence of DP. While MXD is a superior proxy for summer temperatures, there are very few long MXD records from North America. Latewood blue intensity (LWB) measures similar wood properties as MXD, expresses a similar climate response, is much cheaper to generate and thereby could provide the means to profoundly expand the extant network of temperature sensitive tree-ring (TR) chronologies in North America. In this study, LWB is measured from 17 white spruce sites (Picea glauca) in south-western Yukon to test whether LWB is immune to the temporal calibration instabilities observed in RW. A number of detrending methodologies are examined. The strongest calibration results for both RW and LWB are consistently returned using age-dependent spline (ADS) detrending within the signal-free (SF) framework. RW data calibrate best with June–July maximum temperatures (Tmax), explaining up to 28% variance, but all models fail validation and residual analysis. In comparison, LWB calibrates strongly (explaining 43–51% of May–August Tmax) and validates well. The reconstruction extends to 1337 CE, but uncertainties increase substantially before the early 17th century because of low replication. RW-, MXD- and LWB-based summer temperature reconstructions from the Gulf of Alaska, the Wrangell Mountains and Northern Alaska display good agreement at multi-decadal and higher frequencies, but the Yukon LWB reconstruction appears potentially limited in its expression of centennial-scale variation. While LWB improves dendroclimatic calibration, future work must focus on suitably preserved sub-fossil material to increase replication prior to 1650 CE.

The Figure above shows the location of the Yukon study site and includes various other sites the Wooster lab has worked on in Alaska. Rob has been a great help in the efforts at the Wooster Tree Ring Lab facilitating our lab’s ability to perform these analyses.

 

Mary Garvin (Biology, Oberlin College) lead the study using tree-rings and chemical analyses entitled: A survey of trace metal burdens in increment cores from eastern cottonwood (Populus deltoides) across a childhood cancer cluster, Sandusky County, OH, USA.  

Abstract: A dendrochemical study of cottonwood trees (Populus deltoides) was conducted across a childhood cancer cluster in eastern Sandusky County (Ohio, USA). The justification for this study was that no satisfactory explanation has yet been put forward, despite extensive local surveys of aerosols, groundwater, and soil. Concentrations of eight trace metals were measured by ICP-MS in microwave-digested 5-year sections of increment cores, collected during 2012 and 2013. To determine whether the onset of the first cancer cases could be connected to an emergence of any of these contaminants, cores spanning the period 1970–2009 were taken from 51 trees of similar age, inside the cluster and in a control area to the west. The abundance of metals in cottonwood tree annual rings served as a proxy for their long-term, low-level accumulation from the same sources whereby exposure of the children may have occurred. A spatial analysis of cumulative metal burdens (lifetime accumulation in the tree) was performed to search for significant ‘hotspots’, employing a scan statistic with a mask of variable radius and center. For Cd, Cr, and Ni, circular hotspots were found that nearly coincide with the cancer cluster and are similar in size. No hotspots were found for Co, Cu, and Pb, while As and V were largely below method detection limits. Whereas our results do not implicate exposure to metals as a causative factor, we conclude that, after 1970, cottonwood trees have accumulated more Cd, Cr, and Ni, inside the childhood cancer cluster than elsewhere in Sandusky County.

Figure – shows the extent of the cancer cluster that coincides with more accumulated Cd, Cr and Ni in the tree-rings.

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