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Archive for May 2013

UCMP students honored with 2013 Paleontological Society Student Grants Awards

Dori Contreras (Looy Lab), Renske Kirchholtes (Looy Lab), and Allison Stegner (Barnosky Lab) will each receive awards from The Paleontological Society to support their research. Each year the Society grants Mid-America Paleontology Society (MAPS) Outstanding Research Awards to the top three student proposals received and honors a student with the G. Arthur Cooper Award for student research.

Dori, Renske, and Allison

Dori Contreras (left), Renske Kirchholtes (center), and Allison Stegner (right) busy at UCMP's Cal Day open house.
 

Dori Contreras will receive a MAPS Outstanding Student Research Award to support her research titled: Investigating the evolution of tropical rainforests: A functional analysis of the late Cretaceous Jose Creek Member, McRae Fm.

Renske Kirchholtes will receive a MAPS Outstanding Student Research Award to support of her research titled: Phytoliths: a novel application to answering ancient questions.

Allison Stegner will receive the G. Arthur Cooper Award to support her research titled: Assessing small mammal response to Quaternary climate and land use change on the Colorado Plateau.

Barnosky presents statement on global environmental problems to Governor Brown

When California governor Jerry Brown challenged scientists to put global change issues into terms that political leaders can understand UCMP's Tony Barnosky stepped up. On May 23 Barnosky and colleagues presented a 30-page statement entitled Maintaining Humanity’s Life Support Systems in the 21st Century to the governor. It's a strong statement about global environmental problems and what people must do to insure the future health of the planet with signatories from 44 countries including two Nobel laureates, 33 members of the U.S. National Academy of Sciences and members of other nations' scientific academies.

 

Read more about Barnosky and other scientists' presentation to the governor at the UC Berkeley News Center.

 

Read the scientific consensus statement at the Millenium Alliance for Humanity & the Biosphere website.

Another feather in Judy Scotchmoor's cap

Our very own Judy Scotchmoor, Co-Director of Education and Outreach at the UCMP, received the 2013 Chancellor's Award for Public Service. The award honors outstanding public service by UC Berkeley undergraduates, graduate students, faculty, and staff. The Civic Engagement Award received by Judy is, in part, for her exceptional ability to develop, nurture, and leverage collaborative partnerships and resources to better engage the public with exciting and accessible science.

In a public ceremony held on May 9, 2013, at the Alumni House on campus, Judy’s leadership in the Understanding Evolution and Understanding Science websites was highlighted, as well as her efforts in Science@Cal, COPUS, and KQED Quest. Congratulations, Judy!

Judy with the Chancellor

Judy with Chancellor Birgeneau.

Judy at the podium

Photos courtesy of Bruce Cook Photography.

Finding forams in the Caldecott Tunnel

Day after day, over the course of two years, the massive tunnel borer worked its way through the sedimentary rock layers of the Berkeley Hills during the construction of the fourth bore of the Caldecott Tunnel, grinding up the rocks in the process into fist-size pieces that were later deposited outside the entrance of the tunnel. At the end of each work day, paleontologists sifted through these piles, referred to as the day’s "spoils." They were not only on the lookout for fossils of plants and animals; each day they also collected samples of the rocks for later testing for microfossils.

These samples eventually made their way into one of the prep labs of the UC Museum of Paleontology, a room that has become my second home during the spring semester of 2013. One of my jobs as a graduate student researcher on the CalTrans project is to break down and process these rock samples to look for evidence of ancient microscopic life.

Susan with boxes of matrix

Here I am in the UCMP prep lab. In the foreground are some of the microfossil samples to be processed. Photo by Pat Holroyd.

Looking at forams
Microfossils are by definition too small to be studied with the naked eye. A group of microfossils that we are particularly interested in are the Foraminifera, commonly referred to as “forams.” These single-celled amoeboid-like organisms, which are usually about the size of a sand grain, have shells, known as “tests,” often consisting of multiple chambers, arranged in a myriad of configurations. Living specimens extend strands of protoplasm from their tests in order to “communicate” with their ambient environment. This enables benthic (bottom-dwelling) forms to crawl and the planktonic (floating) forms to remain in suspension, while providing both with a means of obtaining food. Forams are common in marine environments all over the world, and their tests are often a major component of marine sediments.

Left: Drawing of the living foram Polystomella strigillata, from John H. Finley ed. Nelson's Perpetual Loose-Leaf Encyclopaedia (vol. 5) (New York, NY: Thomas Nelson and Sons, 1917); Right: © Creative Commons, Mihai Dragos

Foram tests are important fossils because they are paleoenvironmental indicators. As the tiny fossils accumulate in marine sediments they leave records that are often continuous for long geological stretches of time. By comparing the fossils to modern species, we can infer a great deal about the temperature, ocean depth, and depositional conditions that existed at the time that the organisms were living millions of years ago.

Processing the samples
In order to separate the microfossils from the shale and mudstone matrix, we first gently disaggregate the rocks by soaking them in water and adding Calgon water softener to prevent the finer sediments from clumping. If the rocks don’t readily start to disaggregate, heat and hydrogen peroxide are added. Because the shells of forams and other creatures often contain calcium carbonate we do not use acids to break down the rocks or we will dissolve the fossils at the same time!

Breaking up the matrix

Left: First stages of the process; Right: Some of the rocks in this sample are already starting to break down.

Once the rocks have completely broken down, the sediment is rinsed through a sieve with 63 micron (1 micron =0.001 mm) openings to remove silt and clay. After the residue is filtered and dried, it is ready to examine for forams under the stereomicroscope.

Sieving and drying

Left: Sieving to remove the smaller silt and clay particles; Right: Filtered samples drying in the oven.

So far the process sounds pretty straightforward, but the reality of doing science doesn’t always live up to our expectations. The first batch of samples were from the Orinda Formation; these broke down readily but revealed only a few charcoal fragments. The absence of forams was not surprising, as this unit was deposited in freshwater! I am hoping the Orinda will yield some ostracodes (another kind of microfossil), but none have been observed in the material processed thus far.

I next turned my attention to the samples collected from the definitely marine Sobrante Formation. While a few forams were noted on the surface of some partially broken-down rocks, most of the rocks did not break down at all. While experimenting with some alternative treatments on these samples, including soaking them in kerosene, I have begun to process the tunnel samples of the Claremont Formation, which is stratigraphically between the younger Orinda and older Sobrante formation, and represents the final sequence of marine deposition before emergence of the sea floor.

The first batch broke down readily with our gentle treatments and, when the results were viewed under the microscope, the sediment sample contained not only tiny pieces of coalified plants but a fair number of foraminifera shells.

Examining the dried residue

Left: Examining the dried residue under the stereomicroscope; Right: The view through the eyepiece. Each square in the grid is about 4 mm wide.

UCMP’s foram expert Ken Finger identified the three most common taxa as Martinotiella communis, Pyramidulina acuminata, and Lenticulina sp. Today this benthic association occurs on the continental slope, no shallower than 500 meters. Try to identify the three genera in the close up of the microscope photo on the left, below, based on the reference drawings on the right.

Three genera

Read other blog posts about the Caldecott Tunnel fossils:

Fossil neighbors, posted September 12, 2012
The arrival of the fossils, posted October 1, 2012
Prepping the fossils from the Caldecott Tunnel, posted May 16, 2013

All photos by Susan Tremblay except where indicated.

Prepping the fossils from the Caldecott Tunnel

For the last semester I have been lucky enough to work as the GSR (graduate student researcher) for the spring semester at the UC Museum of Paleontology fossil preparation lab (prep lab) under the supervision of our new lab manager, Jason Carr.

It has been fun getting back into the preparation role, something that I did as a job after college. The material we have to work on varies a lot which keeps the work interesting. It requires a variety of techniques, so I get to do something different nearly every day.

marine snailWhen we started this project in the fall semester we stored dozens of boxes and stacked them high at the offsite Regatta storage facility. I have gone through enough material that now all of the boxes are in the prep lab. We are making good progress but there is so much we are still unpacking! But, it is okay because sometimes we find marvelous surprises like this nearly perfect marine snail shell (at left).

We are constantly amazed at the number of different materials that the collectors used to wrap and protect the fossils. One shark tooth was even cleverly protected in a cut-up Coke bottle! I guess you use whatever you can in the field. The majority of the fossils that I am preparing are fish bones and scales — several of the formations that the Caldecott Tunnel plunges through were marine, such as the Sobrante Formation where most of our material was found. We are also finding a variety of plants, charcoal, bones of mammals from both the ocean and the land (including tiny mammal teeth, which will be the subject of a later blog), turtles, whole oyster beds, and whole rock samples that we process for marine microfossils and shells of foraminifera. These are important fossils because they allow us to address questions of climate and stratigraphy and GSR Susan Tremblay will tell you more about the preparation of those materials in her blog.

I am using some quite different techniques than Susan since most of the fossils that I am preparing are visible with the naked eye. Most of what I am doing is surprisingly low tech! It does take a lot of practice though and a good supply of patience. Some fossils are solid enough that we can use special air-powered tools like this pneumatic air scribe.

Ash using the air-scribe

Most of the marine mammal fossils are strong enough for this. The tools vibrate the rock though so more delicate fossils need to be stabilized with resins. I usually apply these with an eyedropper or gently brush them on like you can see here.

Ash applies resin to a fossil

These techniques are simple but really important if the fossils are to last in the collections until someone wants to come examine them.

I am excited to spend this time working in the lab. I love opening a new box and getting to see firsthand some of the remains of the animals that roamed over the East Bay hills. To learn about a world that existed so long ago and was so different that it had camels and rhinos living in it and then to realize that it existed right here in the East Bay? Exhilarating! Hard to picture perhaps but every fossil we unwrap brings us a little closer to visualizing that world.

Ashley Poust

Read other blog posts about the Caldecott Tunnel fossils:

Fossil neighbors, posted September 12, 2012
The arrival of the fossils, posted October 1, 2012

Photos courtesy of Ashley Poust and Jason Carr