Going into my
final year at George Mason University, thoughts of how I would apply my new
knowledge to the working world quickly started to flood my mind. As a biology
major with a passion for paleontology, I decided to dedicate my future to
observing long and short term trends of the past to better understand our
future. Some call this evolutionary biology and others call it conservation
paleobiology. Regardless of its name, I quickly realized I needed to narrow my
focus. To do so, I enrolled in a Paleontological Training Program (PTP) at the
Smithsonian’s National Museum of Natural History (NMNH). During the course we
had many speakers, one of which was Dr. Brian Huber (the chairman of the
Department of Paleobiology). He gave a convincing argument as to why working
with forams in the Department of Paleobiology would be the best place to spend
my summer.
What are forams
you may ask? Forams, formally known as foraminifera, are single celled
organisms that spend their time floating in the ocean (planktics) or dwelling
on the ocean floor (benthics). Most create their shell (tests) out of calcium
carbonate and some are heavily ornamented with agglutinated materials. They also
use spindly pseudopodia to wrangle their dinner, which can be as large as a
small shrimp! Yum. These fascinating microfossils offer valuable insight into
our past and can provide much needed information on current marine ecosystems.
At the end of
the PTP course, I decided I wanted to work with these valuable creatures. Luckily
for me, my current mentor, Miss Loren Petruny had been working with forams for
her Master’s thesis and needed a helping hand. It was through working with her
and Dr. Huber, that I developed a keen interest with forams. Fast forward to
the current summer. With her approval, I decided to expand upon Miss Petruny’s
research in hopes to help streamline the process. I am intrigued by her research taking these
tiny microfossils and rendering 3D printed models.
My journey this
summer has been a broadening experience to say the least. As a volunteer at the
National Zoo and camera trapper for the Smithsonian Conservation Biology
Institute, it is safe to say I am not unfamiliar with the inner goings of the
Smithsonian. However, my internship through URSP has afforded me experiences I
wouldn’t have otherwise been privy to. Let’s look at some of what I’ve been
working on!
As previously
performed by my mentor, I had large shoes to fill and needed to learn many
skills before I could consider broadening her research. In doing so I needed
all the help I could get from various staff at the NMNH. This involved type
specimen selection with the help of the Department of Paleobiology’s Jennifer Jett.
I would also need help with imaging these fine fossils, enter the Scanning
Electron Microscopy lab manager, Mr. Scott Whittaker. Together, Jennifer and I
selected a total of fifteen forams, all with different shell types. I won’t go
into detail of what is what, but we wanted to have enough variety in the event
a particular type was not easily imaged in the scanning electron microscope.
So how does one
image a microfossil the size of a pinhead in a scanning electron microscope?
I’m glad you asked. First needles made of tungsten wire are carefully crafted
using a dipping technique in sodium hydroxide. To expedite the process, an
electrical charge is sent through the fluid. Using the meniscus of the fluid
and repeated depressions in the center, the wire is transformed from having a
blunt end to a fine needlepoint.
The needle is
then used to drill a hole in the center of a carbon stub. I created a total of
five needles and successfully made six stubs (these can be reused as needed). Then using a straight cactus needle, some
dental wax, Elmer’s glue and a lot of steady fingers, the end result is a mounted
foram ready for imaging. Now that my hands are dirty it is time to take some
images! As seen here each foram is imaged one at a time.
Using a series
of images taken from a scanning electron microscope (SEM) at varying degrees,
images are rendered in a photogrammetry program such as AgiSoft. Once complete,
the type specimen will be 3D printed.
As expected,
research comes with many expectations; some are met and some are altered.
Currently this week, I am working to better understand AgiSoft so that I may
align images taken at different depths from two different SEM sessions. Once
this is mastered, the final step is 3D printing our microfossils. This will
complete my summer research and will provide a truly tangible experience.
