Archive for July, 2018

Fieldwork in Estonia, with a bonus visit to Narva

July 31st, 2018

Tartu, Estonia — Today Bill and I had a spectacular geology and culture field trip in northeastern Estonia. As you can see in the images, the weather was excellent, if a little warm. Our Estonian hosts took us from Tartu to several places north and east to the border with Russia. Our fieldwork in an oil shale quarry is shown above, but first our journey there —

Lake Peipsi (or Lake Peipus) is near Tartu. It is one of the largest freshwater lakes in Europe, with the Russian border running down its center. We stopped briefly for this view. It looks like one of North America’s Great Lakes from here. There is much history along these shores.

This is the Kiviõli Concentration Camp Holocaust Memorial near our collecting site today. The 20th century history of this region, especially during World War II, is notably grim and brutal. Relatively little has been published on the German concentration camps in Estonia.

This is the oil shale mine we visited near Põhja-Kiviõli in northern Estonia. The oil shales, in the form of kukersite, are the brown units in the top half of the outcrop. The shales are dug from these pits and then separated from the limestones, which appear light gray. The pits fill quickly with water, so there are massive pumps continually working nearby.

A closer view of an oil shale outcrop. These units are Late Ordovician in age (Sandbian) and nearly unique to Estonia. They are very rich in organic material — up to 55% of the rock. The oil shales are used in a variety of ways for energy and petroleum products.

Finding specimens of the spherical rhombiferan echinoderm Echinosphaerites was one of our goals for this trip. Here is one in limestone. The best are those that are in the oil shale because they pop free of the matrix. We didn’t find very many, though.

Giant bryozoans were surprisingly common in the oil shales. This is the base of a large trepostome. We found many of these bryozoans with beautiful borings. It was a good collecting site.

Here are our delightful Estonian hosts at lunch following fieldwork. From left to right: Olev Vinn (a colleague since 2006), Ingrid Vinn, and Mare Isakar.

Much to our surprise we were able to go to the storied easternmost Estonian city of Narva. This was very much a treat. Narva sits along the Narva River, which is the border with Russia. The city has a high concentration of Russian-speakers and a distinct Estonian-Russian culture. Its history has been, needless to say, complex even to present times.

This is Hermann Castle, also called Narva Castle, the focus of our visit. Hermann Castle is the blocky, high structure. To the right is visible another castle on the other side of the Narva River (see below).

This is that Russian castle opposite the Hermann Castle on the castle on the other bank of the Narva River. It is the Ivangorod Fortress. It makes for quite a striking boundary at the western edge of Russia.

The Narva River between the two castles, looking upstream. The Ivangorod Fortress is on the left. This is effectively the boundary between East and West in Europe.

The Narva border crossing bridge between Estonia on the left and Russia on the right. This is the view from the top of the Hermann Castle. At this point my phone gave me a message: “Welcome to the Russian Federation”.

The interior of the Hermann Castle is a museum. I thought these stone cannon balls were geologically interesting, considering that earlier this summer I saw their equivalents in Wales. Note my foot for scale.

On the way back to Tartu, we visited the town of Sillamäe on the Baltic coast. During Soviet times factories in Sillamäe extracted uranium oxides from local oil shales and then from other ores mined throughout the Soviet Empire. Because of the high concentration of scientists and engineers, this town was built with, shall we say, higher architectural and aesthetic standards than the usual Soviet constructions. It was a “closed town” forbidden to foreigners or even most Estonians.

This is a 1987 statue in Sillimäe celebrating its atomic achievements. By then this town produced almost 100,000 tons of uranium oxides for Soviet nuclear weapons and energy plants. It all stopped in 1989, and when Estonia reclaimed the area two years later there were serious contamination problems to solve. [Update: Cheryl Rofer, Los Alamos National Laboratory (retired), added a comment and a link to her story about the clean-up: Averting a Baltic Sea Disaster. It is an excellent read!)

What a rich trip this was. Thank you again to Olev, Ingrid and Mare.

Starting work in Estonia

July 30th, 2018

Tartu, Estonia — Ah, fossils at last! Bill Ausich and I are here to explore several topics, but the main one is describing the crinoids in a Silurian (Aeronian) Konservat Lagerstätte at Kalana Quarry in central Estonia. Much more on this later, but above is one of the crinoids, from the stem to the calyx to the pinnulate arms. The preservation is very odd, with most of the original calcite dissolved away and considerable carbonization and, maybe, some recrystallization. (Much of the list of preservation modes we teach!)

We’re working in a beautiful teaching lab at the University of Tartu. We have plenty of space to lay out the specimens collected by the geologists here. (These particular quarry beds are no longer accessible.) The microscopes are new and the best student models I’ve seen.

Today was mostly orientation for us in the lab. After dinner we walked down to the Emajõgi River, which runs through the campus and has been very important in Estonian history. Its name means “Mother River”. Beautiful.

First full day in Estonia for the intrepid paleontologists

July 29th, 2018

Tartu, Estonia– Bill Ausich and I arrived exhausted but safely in this old university city last evening. Fortunately we had this gorgeous Sunday to recover and adjust to the seven-hour time difference. We explored the neighborhood around our hotel (“V-Spa Hotell”). This is the city hall building. We had dinner under the umbrellas. It is hot here, with “extreme high temperature” warnings and forest fires to the north.

This statue memorializes the Estonian War of Independence from the Russian Empire (and soon to be Soviet Union) in 1918-1920. If you follow the link you’ll see how complicated these events were. This year Estonia is celebrating a century since it declared independence. Tragically, it has had less than fifty years of actual independence because of Soviet, then German, then Soviet successive occupations.

Concluding 2018 summer research in the Tree Ring Lab

July 27th, 2018

Summer 2018 research in the Tree Ring Lab has come to a close. The group of five students worked on a variety of projects, learning about the climate and history of Ohio and Alaska, and the application of different dendrochronological techniques and statistical analyses. They also gained experience effectively conveying their research to others and writing official reports of their findings.

The summer research team on their last day working together (Left to right: Greg Wiles, Nick Wiesenberg, Victoria Race ’19, Juwan Shabazz ’19, Kendra Devereux ’21, Josh Charlton ’19, and Alexis Lanier ’20).

AMRE students with a sampled oak tree at Brown’s Lake Bog in Wooster, Ohio (Alexis Lanier ’20, Juwan Shabazz ’19, and Kendra Devereux ’21).

The AMRE team accomplished a lot during the eight weeks they were here on campus. Their research started with the principles of dendrochronology, when they learned how to count individual tree rings and measure their widths under the microscopes. From here, the team learned how to run this data in different programs like COFECHA and ARSTAN. This process allowed them to date many historical structures across Northeast Ohio such as Gingery Barn and Miller House and Barn. You can find a full list on the TRL’s reports page.

AMRE students with Nick Wiesenberg collecting samples from historical structures at Sonnenberg Village in Kidron, Ohio.

Alexis and Kendra visiting one of the historical structures at Sonnenberg Village.

The AMRE students also learned how to take these chronologies and make hypotheses regarding past climate by uploading the data to Climate Explorer and running various correlations with other datasets.

We were fortunate enough to go out in the field and personally collect most of the data that we worked with this summer. These eventful trips included a lot of tree coring and required lots of bug spray. Some of the AMRE group’s favorites trips included Stebbin’s Gulch and Brown’s Lake Bog.

Stebbin’s Gulch at the Holden Arboretum (Left to right: Josh Charlton ’19, Juwan Shabazz ’19, Alexis Lanier ’20, Kendra Devereux ’21, and Dr. Wiles).

Juwan with the machete, ready to clear a path for the rest of the team at Brown’s Lake Bog.

Lining up to cross the moat at Brown’s Lake Bog after a weekend of strong thunderstorms.

Kendra Devereux ’21 with the sample bag at Barnes Preserve in Wayne County.

Josh Charlton ’19 coring a tree at Stebbin’s Gulch in the Holden Arboretum.

The other two summer researchers working in the Tree Ring Lab this summer, seniors Victoria Race and Josh Charlton, have been working with tree ring data collected from Alaska. Their work focuses on the modeling of Columbia Glacier located in Prince William Sound, Alaska. They are currently working on an abstract to submit to the upcoming GSA conference this fall. Stay tuned for more information regarding their project!

AMRE students with Victoria Race ’19 and Arrow at Brown’s Lake Bog.

Special thanks to the National Science Foundation, the Sherman Fairchild Foundation and the AMRE program for helping to make this research possible. Enjoy the rest of your summer!

Wooster and Ohio State paleontologists return to Estonia

July 27th, 2018

Bill Ausich (Ohio State University Academy Professor) and I begin a long journey today from Ohio to the delightful nation of Estonia. (I’ve posted a map above in case you’ve forgotten the location of this Baltic country.) We were last in Estonia in the cool summer of 2012, where we had a fantastic combined team of Wooster and OSU students. This time it is just Bill and me with a variety of research goals.

Here is the renowned Professor Ausich as we wait for a transatlantic flight in Newark, New Jersey. (I think he looks like Teddy Roosevelt.) Our first stop is Stockholm, Sweden, and then a flight to Tallinn, Estonia. From there we will take a bus to Tartu, Estonia.

Off we go. More posts later!

Summer Research at Wooster: Rain-on-Snow in Alaska

July 13th, 2018

The following post is courtesy of Anna Cooke (’20), who worked with Dr. Alex Crawford through Wooster’s Sophomore Research Program this summer

In the heat of Ohio’s summer, it’s been a small bit of relief to turn my attention to Alaska; or more specifically, to rain on snow events in Alaska. A rain on snow event is pretty much exactly what it sounds like. It occurs when rain falls on a preexisting snowpack. For this to happen, the temperature must rise above freezing during a precipitation event. If the temperature then falls below freezing following the event, the result is a layer of ice on the surface of, in, or underneath the snowpack.

But why should those of us who live in the continental interior care?

Rain on snow, hereby referred to as ROS, has some interesting and possibly devastating effects. One such effect is on caribou populations. The diet of Alaskan caribou varies, but something that most caribou have in common is the dependence on ground foliage, such as lichens, as a winter food source (Joly et al., 2015). ROS is dangerous for caribou because of the possibility that the resulting ice layers will block this food source. Nutritional stress caused by ROS can lead to declining birth rates and calf weights. At the most extreme, mass die-offs can result from starvation (Mallory and Boyce, 2018). The resulting population decline or emigration of caribou impacts the hunters who rely on the caribou as a food source.

Fig 1: Caribou photo courtesy of Dr. Karen Alley.

Other impacts of ROS include the shutdown of airports and loss of revenue from tourism, and permafrost degradation. If enough rain infiltrates through the snowpack to its base, when it refreezes, the latent heat that is released will maintain a soil temperature of 0 degrees Celsius when it should be much colder. The resulting warming of subsurface temperatures could destabilize permafrost systems, causing slope instability and avalanches (Rennert et al., 2009).

Identifying ROS Events

If we want to mitigate the effects of ROS events, it is important that we understand where, when, and how often they occur. To do this, ROS can be identified and analyzed using climate models, satellite data, and observational data from weather stations. One difficulty in identifying ROS events is that no one agrees on just what a ROS event is. Some people define it as 3 mm of rain falling on 5 mm of snow water equivalent, or SWE, which is the amount of water present if the snowpack were to be melted. Others use different thresholds than 3 and 5 mm. Some use measures such as over 12 continuous hours of precipitation visually classified as drizzle and greater than 0.0 mm.

Despite this variation all identification strategies share one limitation: none keep track of refreezing after the precipitation event. This is an issue because ROS without refreezing does not have the same impacts as ROS followed by freezing, and if we are interested in the events most likely to have strong effects, refreezing is imperative.

I experimented with different identification strategies and thresholds trying to find a method that was restrictive enough that I wasn’t overcounting the number of events, but not so stringent that I was undercounting. The graphs below show the average number of events per year divided by season at five different weather stations in Alaska when counting events as 0.1 inches of precipitation on 0.1 inches of SWE, or 1 inch of snow depth for stations where SWE is not available. The first graph shows the total number of ROS events counted. The second graph shows the number of ROS events followed by refreezing. In all cases, fewer events are counted when refreezing is accounted for, and in several cases no more than half of ROS events are followed by refreezing. Thus, it’s likely that many studies are overestimating the number of impactful ROS events.


Fig 2: Number of rain on snow (ROS) events per year by season for (top) all events and (bottom) events followed by refreezing.

As you can see from the graph above, most ROS events seem to occur in the spring, which is defined as March, April, and May. ROS functions a bit differently depending on the season. In the fall, the temperatures are often warm enough for rain to occur, but there may not be a snowpack for the rain to fall on. In the winter, the limiting factor is not snowpack, but rain, since the precipitation that falls is more likely to be snow. In the spring, the presence of a snowpack and the increase of the temperature to allow for rain are likely. However, a refreezing event is less likely. Moreover, even if there is refreezing afterwards, the number of days that the temperature remains below freezing is likely to be lower than the number of days for a winter event.

As such, events in each season pose different threats to caribou herds. In the fall, healthy caribou which have spent the summer with plentiful food access are more likely to be weakened than killed off. However, major winter events in which the snowpack is frozen over for weeks afterwards are more likely to decimate populations. Events in the spring are also dangerous because, even though the ice is not likely to inhibit foliage access for more than one or two weeks at a time, caribou may already be weakened from harsh winters.

Since there are so many factors to take into account in the study of ROS events, more research is necessary, especially since the frequency with which events occur is likely to increase with global warming. There are ways that we can mitigate the effects of ROS on wildlife and human populations, but only if we can understand its causes and effects. The research done this summer is piece of a larger story, and it was a pleasure to add this piece to the puzzle.

Fig 3: Caribou photo courtesy of Dr. Karen Alley

Works Cited:

  • Joly, Kyle, Samuel K. Wasser, and Rebecca Booth. 2015. Non-Invasive Assessment of the Interrelationships of Diet, Pregnancy Rate, Group Composition, and Physiological and Nutritional Stress of Barren-Ground Caribou in Late Winter. PLoS One, 10 (6): 1-13 (DOI: 10.1371/journal.pone.0127586).
  • Mallory, Conor D. and Mark S. Boyce. 2018. Observed and predicted effects of climate change on Arctic caribou and reindeer. Environmental Reviews, 26 (1): 13-25.
  • Putkonen, J., T.C. Grenfell, K. Rennert, C. Bitz, P. Jacobson, and D. Russell. 2009. Rain on Snow: Little Understood Killer in the North.EOS,90 (26): 221-222.
  • Rennert, Kevin J., Gerard Roe, Jaako Putkonen, and Cecilia M. Bitz, 2009. Soil Thermal and Ecological Impacts of Rain on Snow Events in the Circumpolar Arctic. Journal of Climate,22: 2302- 2314 (DOI: 10.1175/2008JCLI2117.1).