Wooster’s Invertebrate Paleontology class at work

September 18th, 2018

Wooster, Ohio — The Invertebrate Paleontology class at Wooster set to work this afternoon on the excellent fossils they collected at the beginning of last week. They had already washed them carefully, using soft brushes and soap, and now were learning how to trim them down with our faithful basement rock saw. Grant Holter is seen above doing his very first cut. All the specimens are from a single outcrop of the Upper Whitewater Formation (Upper Ordovician, Katian) just south of Richmond, Indiana.

The spinning steel blade has industrial diamonds embedded in its periphery, which grind quickly through our soft limestones. The blade and rock are continually sprayed with water to keep the blade from overheating, lubricate the cut, and to capture the dust. The newbies to our saw learned fast.

Each student has two trays of specimens, which are right now in their raw, unprepared and unlabelled state. Julia Pearson examines her very full trays. Juwan Shabazz is behind her.

A closer look at Julia’s treasures.

An even closer view. We can easily now identify abundant brachiopods, bryozoans, and rugose corals — the big three groups.

Finally for today the paleo students learned how to label their specimens using water-soluble white glue and printed paper tags, a technique I learned at the University of California Museum of Paleontology.

Next week the class will use the saws, grinders, polishing plates and hydrochloric acid to make acetate peels. This is my favorite paleo process!

2018 Invertebrate Paleontology field trip — with the Ghost of Gordon

September 9th, 2018

The Invertebrate Paleontology class at Wooster had its annual field trip today to the Upper Ordovician (Katian) Cincinnati Group (Upper Whitewater Formation) in eastern Indiana. The weather looked terrible as the remnant of Tropical Storm Gordon worked its way into the Great Lakes region. Three to five inches of rain were forecast for our field area just south of Richmond, Indiana (locality C/W-148). For all I know, that massive amount of rain actually fell today — but not while we were there! As you can see above, we collected treasures in the dry. In fact, the specimens were nicely washed for us, with the fossils standing out better than I’ve ever seen.

Here’s a random image of the rubbly limestone we examined. Count the bryoimmurations! This is perfect material for beginning paleontology students. Each one made a representative collection to clean, prepare and interpret in our cozy Wooster lab the rest of the semester.

We’ve certainly had better weather here in past years, but I’m not complaining about today. We slipped by a ghost.

Using Snow to Predict Sea Ice

August 24th, 2018

One of my active areas of research is trying to find physical links in the Arctic climate system that may help us better predict when seasonal sea ice cover will disappear each summer. Good sea ice predictions are important because shipping, tourism, resource extraction, and any other human activity in the Arctic Ocean is much more dangerous when sea ice is present.  As the open water season gets longer (thanks to global warming), more shipping companies (like Maersk) are using the Northern Sea Route through the Arctic Ocean. The earlier we know when the sea ice will be gone and the waters open, the earlier we can plan shipping schedules.

The Northern Sea Route through the Arctic Ocean and the day sea ice concentration falls below 50% (left) or 15% (right).

A recently accepted article at the Journal of Geophysical Research: Atmospheres by myself and colleagues in Colorado and the UK describes how one physical link that can help predictions is when snow cover retreats in Siberia.  More specifically, the paper focuses on how snow retreat in the West Siberian Plain (WSP) can help predictions of sea ice retreat over 1,200 km (over 700 miles) away in the southern Laptev Sea (SLS).  It’s a complicated system of interactions, but here’s the short version:

1. When snow disappears from the West Siberian Plain (WSP), the land surface warms up quickly and releases substantial energy up to the atmosphere.

2. That energy generates waves in the atmospheres. Unlike waves in the ocean, which make swimmers and boats bob up and down, these waves oscillate north and south.  When they first initiate, these waves look like a northward bulge or ridge on a map.  The arrows below show the way winds blow when a wave occurs. Warm air moves north (red arrows) on the west side of the ridge and cold air moves south (blue arrows) on the east side.  (This phenomenon of waves in the atmosphere is a big reason why temperatures vary so much in the Midwest, by the way.)

3. The geography of Siberia is special in being a huge swath of land without major impediments like the Rockies, Alps, or Greenland ice sheet. This allows the waves to easily migrate without breaking down.  Therefore, as the waves build in late spring, they also shift eastward.

4. By June, the wave setup is fully formed, with the main ridge not over the initiation point, but rather  the southern Laptev Sea.  This means winds that blow from south to north over the Laptev Sea, carrying warm, moist air — air that is ideal for melting sea ice.

5. In this way, earlier snow retreat from the WSP means earlier wave generation in the atmosphere and earlier sea ice melt in the southern Laptev Sea.

This link isn’t the only thing that matters — it only explains around 1/3 of the variation of sea ice retreat in the Laptev Sea.  However, for one variable in a complicated system like this, 1/3 is actually really helpful.  Moreover, the snow typically disappears in the WSP in late April, and the sea ice doesn’t retreat from the southern Laptev Sea until late July — on average, there’s about 90 days in between.  That’s a lot of planning time. For the interested parties, here’s a more detailed flow chart of the relationships being described in the paper:

Full Citation:

Crawford, A. D., Horvath, S., Stroeve, J., Balaji, R., & Serreze, M. C. (2018). Modulation of Sea Ice Melt Onset and Retreat in the Laptev Sea by the Timing of Snow Retreat in the West Siberian Plain. Journal of Geophysical Research: Atmospheres, 123. https://doi.org/10.1029/2018JD028697

2018 Expedition to Estonia

August 10th, 2018

Bill Ausich (Academy Professor, Ohio State University) and I just finished an excellent research trip to Estonia. As is the custom on this blog, here are the relevant posts in chronological order:

July 27: Wooster and Ohio State paleontologists return to Estonia
July 29: First full day in Estonia for the intrepid paleontologists
July 30: Starting work in Estonia
July 31: Fieldwork in Estonia, with a bonus visit to Narva
August 1: Back to the paleontology lab in Tartu, Estonia
August 2: Starting work in the University of Tartu Natural History Museum
August 3: Back to work in the University of Tartu Geology Department
August 4: Saturday at the Estonian National Museum (plus a street festival)
August 5: Sunday at the University of Tartu Natural History Museum — this time as tourists
August 6: Last day in the University of Tartu Geology Department — and a great garden party
August 7: Last day at the Tartu Natural History Museum, and a visit to a grim museum
August 8: Wooster and Ohio State Paleontologists in Tallinn, Estonia

One of the gorgeous Estonian crinoids from the Silurian we studied. See posts for details!

Wooster and Ohio State Paleontologists in Tallinn, Estonia

August 8th, 2018

Tallinn, Estonia — This morning Bill Ausich (Ohio State University) took the bus from Tartu to Tallinn to finish one more research task and then prepare for the long journey home. Above is the view from my hotel room towards the Old City section of Tallinn.

After getting settled, we visited Ursula Toom at the Department of Geology, Tallinn University of Technology. She and Bill (above) exchanged crinoids, and then Ursula discussed with me a wide variety of Ordovician borings as part of her dissertation work.

This is a small part of the various mystery specimens Ursula shared with me. There are some fantastic undescribed borings in this lot.

Afterwards Bill and I had an early evening dinner in the Old City, beautiful in the setting sun.

Our research in Estonia is done! Tomorrow we pack up and then walk around Tallinn taking in the sights and culture. On Friday we fly home. I hope to describe the results of our work soon in this blog.

Can Heat Flow in Ocean Models Predict Seasonal Arctic Sea Ice Retreat?

August 8th, 2018

Note: The following blog post is by Ben Sershen (’19), who worked with Dr. Crawford on a summer research project.

Source: https://csmphotos.wordpress.com/2013/01/17/bering-sea-opies-and-the-reality-of-the-deadliest-catch/

Intro: My summer research work aimed to further my Junior I.S. in the fields of oceanography and climatology. My research question was: “How well do computer ocean models work for predicting the melt of Arctic sea ice?” This is an important question to ask because many companies are looking to use the Arctic as a shipping passage. To answer this question, I analyzed the data from two models: The Simple Ocean Data reanalysis (SODA) and the Ocean ReAnalysis System 4 (ORAS4), which was produced by the European Center for Medium-Range Weather Forecasts (ECMWF). SODA and ORAS4 are programs that uses physics as well as real-world data, such as from underwater moorings, automated Argo floats, and satellites, to estimate aspects of the oceans such as temperature, water velocity, and salinity. These data could then, in theory, be used to determine when the enough heat has entered the Arctic Ocean to melt sea ice each year.


Figure 1: (Left) A map of the Bering Strait with the A3 mooring location labeled. The Chukchi Sea is the area to the north (above) the strait. The magenta line represents the location of my study. (Right) A similar map of the Bering Strait with the Alaskan Coastal Current (ACC) and the Siberian Costal Current (SCC) represented by the red and blue arrows, respectively (Woodgate et al., 2015).

Methods: I focused on the Bering Strait/Chukchi Sea region. This area is important as it is the strait where warm water enters the Arctic, as seen in the second map in figure 1. I calculated how much heat was passing through the Bering Strait, into the Arctic using data from SODA and ORAS4. Once I had done this, I had to compare my results to the data from the A3 mooring. This was done by first performing simple correlations (when the heat flow increases do the mooring temperatures increase?). I then correlated the heat flow values to sea ice data – more specifically, the date of the year when the sea ice concentration in the Chukchi Sea dropped below 30%. As heat flow increases, the ice melts faster, retreating earlier. To be a good predictor of sea ice retreat, the heat flow from the models must show this relationship (a positive correlation between the amount of heat and the rate of ice melt).


Figure 2: An example of a cross-section contour plot through the Bering Strait. The darker red represents more heat traveling through the cross-section at that location. The location of the cross-section is marked by the magenta line on the left map in figure 1.

Results: I found that SODA was only accurate when there were mooring data being fed into it. That meant that SODA would not do a very good job at predicting future ocean heat because it relied heavily on real-world data. I performed the same data analysis of ORAS4 that I had performed on SODA and found that ORAS4 produced data that was closer to the mooring data even when mooring data was not available. The ORAS4 data also had a stronger correlation with the sea ice data. I would guess that this is because the ORAS4 is simply better than the SODA model generating realistic data. The ORAS4 model focused on tropical data to generate data and produced better data than SODA, which had a bit more of an Arctic focus. I think that result goes to show how interconnected the world’s oceans really are if you can make accurate predictions of the temperature of the Arctic Ocean from data produced by a tropical model. Using the monthly heat flow values from ORAS4, I created a heat map to visualize the data (figure 3).

Figure 3: A heat map of heat flow data from ORAS4. The y-axis represents months of the year. Note the warmer values occurring in June-October. This represents the seasonal cycle. The x-axis represents years 1990-2017 which illustrates substantial interannual variability.



Last day at the Tartu Natural History Museum, and a visit to a grim museum

August 7th, 2018

Tartu, Estonia — Bill Ausich and I started our last full day in this city at the University of Tartu Natural History Museum, finishing our work with the marvelous Mare Isakar, pictured above. Mare quickly found the specimens we needed, and many others she knew we would find interesting. She did nearly instant registration of specimens, greatly speeding up our taxonomic progress.

We finished photographing museum specimens for our future reference and possible publications. Bill concentrated on Silurian crinoids and I worked on the Ordovician rhombiferan Echinosphaerites.

This is one of Öpik’s Echinosphaerites aurantium specimens. Two roundish encrusting brachiopods are visible, along with sheet-like bryozoans. Shockingly, there are gouges in the bryozoans as if someone tried to scrape them off!

Most of the rhombiferans are filled with sediment and/or calcite crystals, but Bill found this hollow one in the collections. Note that it was still able to resist sedimentary compaction. Also note the bryozoans on the broken edge.

This broken specimen shows sediment in the bottom of the skeleton and crystals in the top half. This is known as a geopetal structure where the sediment shows what was the lower part of the skeleton when it was filled. Here’s another example.

Mare found even more specimens of Echinosphaerites today, so there is much to do on a later trip! Thank you again to Mare Isakar and our other friends in Tartu. Tomorrow we travel to Tallinn for a bit more work before heading home on Friday.

And now for something darker — the KGB Cells Museum in Tartu. It is a horrifying place of pain, anguish and hopelessness, yet today is surrounded by a vibrant, free city and country. This museum, in an actual KGB prison, is both disturbing and ultimately inspiring. It is a history we avoid at our peril.

A cell door near the entrance to this basement complex of “the grey house”. These dungeons were used by the Soviet secret police for detention, torture and executions in the 1940s and 1950s. For a brief interval (1941-1944) the Nazis took over and did the same beastly activities. The victims were almost entirely Estonians.

A hallway of cells. The exhibits inside the rooms include many Soviet artifacts, along with stories of Estonian resistance.

A KGB mannikin at the end of a hallway. A sound track of a harsh Russian voice plays in a loop here, along with inevitable screams and moans. The brutality of the place is quite evident enough, thank you.

Finally, before you leave, why not dress up as a Soviet KGB officer and pose with Stalin? I don’t understand why anyone would do such a thing, especially in such a tragic space.

Tomorrow it is back to science as Bill and I take the bus to Tallinn. The countryside of free Estonia is beautiful.

Last day in the University of Tartu Geology Department — and a great garden party

August 6th, 2018

Tartu, Estonia — As a sign we’re near the end of our work in Tartu, there are no crinoids in this post. Instead, above is an Ordovician bryozoan from Estonia that encrusted the aragonitic shell of a nautiloid. The aragonite dissolved away, giving my favorite underside view of a bryozoan attachment from its ancestrula. We’ve seen this more than once in this blog. The bonus here are the just-visible chains of little crystalline teardrops across the surface.

These are the zooids of the cyclostome bryozoan Corynotrypa. They are encrusted right-side-up, meaning that they grew across the exposed attachment surface of the big bryozoan. The nautiloid shell thus dissolved between the two encrusting events — very early on the seafloor. Classic calcite sea dynamics.

After sorting out the specimens used in our crinoid studies, and doing some last microphotography, we finished our work for this season at the University of Tartu Department of Geology. A small and happy garden party followed.

Bill Ausich and some of our Estonian colleagues and friends. From the left is Oive Tinn, Mare Isakar, Bill, and Viirika Mastik. Great conversations. It actually got a little chilly outside, so we ended in Oive’s house (see below).

Sunday at the University of Tartu Natural History Museum — this time as tourists

August 5th, 2018

Tartu, Estonia — Bill Ausich and I returned to the Natural History Museum today to tour the public exhibits. It was hard to not make it into a study trip, though, for our research. I suppose since our “work” is so enjoyable it is difficult to separate it from a holiday. Above, for example, is a display of our favorite rhombiferan, Echinosphaerites aurantium of the Estonian Upper Ordovician.

There is a display about the Kalana Lagerstätte that we are studying.

Here is the museum description of the Lagerstätte.

And a close-up of some crinoids (“meriliilia”, sea lilies) from the Kalana.

It is a fun museum with a very thorough geology section, including meteorites you can touch (a favorite of mine). It has what is now an old-fashioned style of emphasizing actual specimens that Bill and I appreciated. There is a large biology section with much taxidermy and mounted skeletons. One of the featured exhibits is a rare “rat king” (see below), which you must look up!

Saturday at the Estonian National Museum (plus a street festival)

August 4th, 2018

Tartu, Estonia — This morning Bill Ausich and I walked to the new Estonian National Museum, shown above. It has a most unusual elongated building constructed on an abandoned secret Soviet airbase for bombers (Raadi Airfield). It follows an old runway with the revetments still in place. It is striking.

Parts of the Soviet base are still preserved, including these concrete fence posts.

This is an old Soviet air force garage on the way to the museum. This base was so secret that the entire city of Tartu was closed to foreigners. Now Bill and I stroll the grounds. We did the same in a once-secret Soviet missile base on Saaremaa.

The front entrance of the Estonian National Museum.

I don’t have a lot to show you in the museum itself, since it is mostly about fold and cultural history (which was fascinating). Bill and I appreciated the digital signs. They appear first in Estonian, like this one. We were issued special language cards, though.

When we pass the “English” card across the sensor, the text is instantly translated! Very clever.

Across the road from the museum is an upside-down house. It is apparently quite the tourist attraction, but we passed.

Back in the city center, in fact in front of our hotel, was a street festival. It had live music, fantastic food, and large, happy crowds.

There were lots of fried fish stands, with fish from the local lakes and the Baltic.

Here is Bill waiting for a meal. Impressively, by 10 pm the festival was over, and the streets completely clear the next morning. This is a very efficient, sensible country!

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