Dr. Karena Nguyen, Disease Ecologist

What is your favorite part about being a scientist, and how did you get interested in science?

The best perks about being a scientist are sparking wonder and creativity in others (especially the general public!), hearing about ongoing research in other fields, and conducting interdisciplinary research to integrate knowledge across disciplines.

During my time as a Ph.D. student, I did a variety of volunteer projects to engage members of the Tampa community. Science is for everyone, and the best scientists can and do communicate their work to the general public!

I stumbled into science the way most scientists do (I think) – completely by accident. I was set on being pre-med, but when I took Biology II my second semester freshman year, I fell in love with ecology. While everyone else was griping about the topic, the interactions between species and the environment made sense to me. The professor teaching the class noticed and took me under his wing. I started doing undergraduate research in his lab and took General Ecology a couple years later. There was one lecture on disease ecology and I still remember how it sparked these additional questions in my mind, e.g. how does the environment influence the spread of infectious diseases? I was totally hooked from then on and decided to pursue graduate school to answer these questions.

What do you do?

I am mainly interested in how environmental factors, especially temperature, influence interactions between parasites and their hosts. For my dissertation, I studied a human parasite, Schistosoma mansoni, and its intermediate snail host, Biomphalaria glabrata. The parasite must infect a snail before it can infect humans, and I examined how temperature influenced the parasite at various points of its life cycle, in addition to how temperature affected infected snails over time (see figure). I combined published data and laboratory experiments with mathematical models to predict how disease transmission may shift in response to changing temperatures under global climate change conditions.

The life cycle of a parasite. Image credited to @kes_shaw

What are your data, and how do you obtain them?

For my dissertation, I used a combination of published data and data from laboratory experiments to simulate how changes in temperature influence the parasite and its intermediate snail host.

How does your research contribute to the betterment of society?

Infectious diseases of humans and wildlife are increasing due to complex interactions between human population growth, changes in agricultural supply and demand, and global climate change. For example, human population growth is driving increases in agricultural development and accelerating global climate change. As more habitats are cleared for farmland, the likelihood of humans encountering wildlife that carry infectious diseases will likely increase. Global climate change may also influence how easily these diseases are spread between humans and wildlife. Thus, the broader goal of my research is to improve predictions of disease spread so that the public health sector can improve the timing and application of intervention methods. By examining how one part of the puzzle affects disease transmission, we can disentangle what to expect in the future as interactions between humans, animals, and environment continue to change.

Dr. Nguyen is now a postdoctoral scholar at Emory University. Learn more about Karena’s research on her website and by following her on Twitter @Nguyen_4Science

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Big Bone Lick State Historic Site

Mike here –

I recently visited Big Bone Lick State Historic Site (Union, Kentucky) on the way back to Ohio from a weekend in Kentucky. I’ve been meaning to visit this place for years, so I’m glad I finally had a chance to do so! Big Bone Lick is an important site for paleontology, archaeology, and US history.

Big Bone Lick SP is the site of a salt lick, or area where animals come to obtain salt and other minerals by licking the soil for salt crystals. Natural salt and sulfur springs are the source of the minerals at Big Bone Lick, and they attracted animals from all over.

In historical times, white-tailed deer and North American bison visited the lick, but much larger mammals came during the Pleistocene epoch (2.5 million to 12,000 years ago), also called the “Ice Age.” The remains of extinct mastodons, mammoths, North American horses, ground sloths, and tapirs have been found here, as well as the still living bison, musk oxen, and peccaries. Some of them became stuck in mud and died, and their preserved skeletons became the source of the “big bones!”

Diorama of a modern bison taxidermy with ancient neighbors.

Paleoindians hunted the megafauna at Big Bone Lick, and left behind their tools at the site. Native Americans continued to hunt here into colonial times, and told the Europeans about the big bones found in the soil. President Jefferson ordered Merriweather Lewis and William Clark to stop here on their expedition to investigate these reports. Specimens were excavated and eventually sent to France for analysis by Georges Cuvier, an anatomist credited with developing the concept of extinction. He compared the remains of Asian Elephants, African elephants, and the “elephants” found at Big Bone Lick and determined that these remains came a type of elephant that no longer lived. He named this animal Mastodon, but these fossils had already been described under the name Mammut. The study of these remains has given this site credit for the birth place of vertebrate paleontology in the United States.

The visitor’s center is on Mastodon Trail!

Long after the bison were extirpated (no longer present in their native habitat, but not extinct) from Kentucky, Kentuckians mined salt and opened a health resort, at which people bathed in the mineral-rich water. 

I have always loved the Pleistocene megafauna, and I make a point to see these fossils whenever I can. Mastodons are tied with Moropus (a distant relative of horses and rhinos, imagine a draft horse with claws!) as my favorite fossil animal, and get so excited seeing them! 

The visitor’s center has nice displays about the megafauna found at Big Bone Lick, including fossil material and reconstructions of what they may have looked like. There is information about the Paleoindians that inhabited this region and their tools. Historical information about Lewis and Clark is also included in the displays. 

A mounted giant ground sloth skeleton, and a display comparing mastodons and mammoths.

Behind the visitor’s center are life-size statues that represent iconic Pleistocene megafauna. Many of them are“trapped” in the sediment, and are on their way to become fossils. This was the perfect opportunity for a selfie with a mastodon!

A trapped mammoth and a dying bison.
My selfie with a mastodon!
A giant ground sloth.

The site is actually quite large, and features a campground and several hiking trails. I took one of these trails to see the salt/sulfur springs. I could smell the sulfur as soon as I reached this point in the trail. It was pretty awful, and it amazes me that people came to bathe in these waters for the “medicinal properties” centuries ago. 

A salt/sulfur spring with salt crystals.

I continued along a trail which follows Big Bone Creek. Fossils and artifacts are still exposed as the sediment washes away, and modern excavations occur when fossils are found on site.

These signs are all over the site.

 

Big Bone Lick Creek. Fossils are still exposed as the sediment is washed away through erosion.

Informational signs are included along the trails about the history of the site and about the animals that once lived in this region. 

The park maintains a small herd of American bison (Bison bison) on its grounds. The animals are rotated around their paddock to allow the plants time to recover from grazing and trampling. Unfortunately for me, they were located too far away for me to see with them with my limited time. It is hoped that the ecosystem will be restored to its condition before the bison were extirpated from this area. 

There be bison. Somewhere…

I had a great visit to Big Bone Lick State Historic Site! If you enjoy ice age megafauna, and are in or near Kentucky, consider stopping by! For more information, visit Big Bone Lick State Historical Site

Collection Management

Jen here – 

A graphic I made for Science-A-Thon this year explaining what a collection manager actually manages!

I recently started a new position as a Research Museum Collection Manager at the University of Michigan Museum of Paleontology (UMMP). I am in charge of taking care of the invertebrate fossil collection, which are housed at an off campus facility with all of the other natural history museum collections (anthropology, zoology, and the herbarium). My position involves a lot of moving parts. I took over for someone who had moved the collection twice in the past several years – which is an astronomical endeavor. I have started with working to get a lot of paperwork organized. Specifically the loan paperwork. Research museums loan out specimens to other institutions and borrow specimens from other institutions! Usually there is a lot of paperwork associated with this but not everything is always organized or clear. I’ve spent quite a bit of time working to make sure I know who has specimens of ours and trying to reach out to others to return specimens. I’m nowhere near done but I have a good handle on the last decade, which I consider a victory!

I have recently employed several undergraduate students to help me get a better handle on what is actually in our collection. All of the type and figured specimens are in our local database but they were entered from the card catalog rather than examining the specimens and specimen labels. So, we want to make sure all the information matches and update it if it doesn’t! We are also working to take images of the types to attach them to the specimen records. This is a huge task and I am happy to have some help. 

Here is a peak inside one of the cabinets! The drawers are filled with specimens and how we store them is important for the longevity of the fossils and materials!

I also have been organizing the collection, after the move there were lots of boxes and pallets with miscellaneous fossils and I’m working to figure out what is what. Some of this was easy, some of it involved going through some really nasty old news paper that was used as packing material decades or even a century ago. It’s really important that the collection stay clean because the specimens are housed in compactor shelving. Meaning that if you are trying to get to one area you may have to move other cabinets and it can be difficult to try to look in different time periods or collections at the same time.

Part of my job includes bringing people into the collection. This could be researchers to study the different animals in the collection or conduct geochemical analyses or even high school students looking to pursue a career in paleontology. Every week I have at least one visitor, which is great for the collection. Next week, two folks from the Earth and Environmental Sciences Department are coming to explore some of our Cenozoic material as they are interested in understanding the ancient climate along the eastern coast of the United States. To do this, they use shells from the collection to reconstruct what the environment may have been like!

Understanding the Permian-Triassic transition with fossil data before and after the mass extinction event

Environmental instability prior to end-Permian mass extinction reflected in biotic and facies changes on shallow carbonate platforms of the Nanpanjiang Basin (South China) 

Li Tian, Jinnan Tong, Yifan Xiao, Michael J. Benton, Huyue Song, Haijun Song, Lei Liang, Kui Wu, Daoliang Chu, Thomas J. Algeo

Summarized by: Baron C. Hoffmeister. Baron Hoffmeister is currently an undergraduate senior at the University of South Florida pursuing a degree in Environmental Science and Policy with a minor in Geology. After graduation, he plans to attend a graduate program for environmental management. When graduate school is complete, he plans on working for the National Parks services. Baron is apart of the geology club as well as the fishing club and spends his free time hiking, fishing, and socializing with friends.

What data were used? Fossil taxa found in Southern China carbonate platforms that date back to the Permian-Triassic extinction event, ~251 million years ago. This data sheds light on the mass extinction event that spans the Paleozoic and Mesozoic Eras. 

Methods: Analytical evaluation of fossils present from three separate stratigraphic areas across South China, from before, during, and after the Permo-Triassic extinction event. 

Results: In this study, the fossil data evaluated at each site led to the discovery of common trends. Each formation had similar fossil accumulations, even though the formation would have been located a far distance apart. This means that each location was affected similarly  by the same event for the accumulation of similar fossils to appear in the corresponding strata. This is hypothesized to be the late Permian mass extinction. Another similarity between the three areas was that each section had a foraminifera gap between strata boundaries. At the same time, each boundary represented a different aspect of a shallow marine environment. For example, the Wennga Formation had strata before the extinction boundary that was littered with Permian fauna fossils that occurred in shallow marine environments. Post-extinction boundary strata didn’t possess these fossils. This is another indication of the severity of the mass extinction event. The Taiping section had different types of rock formations with different compositions; the transition of the rock from before the extinction to after showed a rapid die-off of organisms living in this area. Finally, in the Lung Cam section, there were fewer fossils than the other two (most likely due to poor fossil preservation conditions); however, the fossils that were found resembled those in the other sections studied. Further, the Lung Cam section had foram gaps consistent with the other sections.

Skeletal composition within strata at each study section. The three sections had similar organisms preserved in each and even showed similar gaps in fossil occurrences, indicating where the extinction event happened.

Why is this study important? This study strengthens what we know about the Permian-Triassic transition. These fossils, across multiple areas, were present in a shallow marine environment and were greatly affected by environmental instability during this time. The strata at each location, Wengna, Taiping, and Lung Cam, are remnants from the fatal conditions in the marine environment at this time. This can better help us understand and conceive how shallow marine organisms could be affected today during climate change. 

The big picture: This study shows the significant changes in fossils from  before and after the largest extinction event in Earth’s history. There is consistent evidence within and between each section studied, indicating a widespread event that negatively affected shallow marine life during this time.

Citation: Tian, Li, Jinnan Tong, Yifan Xiao, Michael J. Benton, Huyue Song, Haijun Song, Lei Liang, Kui Wu, Daoliang Chu, and Thomas J. Algeo. “Environmental instability prior to end-Permian mass extinction reflected in biotic and facies changes on shallow carbonate platforms of the Nanpanjiang Basin (South China).” Palaeogeography, Palaeoclimatology, Palaeoecology 519 (2019): 23-36. DOI: 10.1016/j.palaeo.2018.05.011

Relationship between Climate Change and Cannibalistic Gastropod Behavior

Indirect effects of climate change altered the cannibalistic behaviour of shell-drilling gastropods in Antarctica during the Eocene

Gregory P. Dietl, Judith Nagel-Myers, and Richard B. Aronson

Summarized by Joseph Ferreira. Joey is a senior at the University of South Florida in Tampa. Joey is pursuing his B. S in geology and is planning on finding a job either in the hydrology or seismology field. He has aspirations of owning his own business one day providing geo surveying services to companies in need of them. In his free time, Joey enjoys playing guitar and hanging out with his friends and family.

What data were used? The samples in this study included nearly 2,000 Naticidae Falsilunatia gastropod (snail) shells that were preserved well enough to show bore holes made from the cannibal snails. These samples were from a time frame in the Eocene that experienced mass cooling event. These samples came from 108 different localities in Seymour Island, Antarctica.

Methods: The prediction made during the start of this study suggested that the cooling temperatures would result in a decrease in the cannibalistic behaviors of these gastropods; meaning,  the colder temperatures would make it more difficult for the mollusk to maintain a productive activity level. To test their hypothesis, each drill hole found on the gastropods (complete or incomplete) was counted and the frequency of cannibalism was found by dividing the number of drilled samples by the total number of specimens in the group. The scientists looked at how frequent the drilled holes were in the specimens and also the body size of each specimen. They connected these specimens to a time either before, during, or after the known cooling event. They then looked to see if there were any significant changes in the frequency of these cannibalistic drill holes.

Figure showing Seymour Island in Antarctica (image A) where the study took place along with (image B) a sample with a perfectly drilled hole and a sample with an incomplete drill hole from another Falsilunatia gastropod. Image C shows one of the cannibalistic snails from multiple angles.

Results: When comparing the number of attacked specimens from before, during, and after the cooling event that occurred nearly 41 million years ago, the frequency of cannibalistic tendencies did not decrease or increase, but they remained stagnant. There was a very slight increase in frequency, but this increase was not statistically significant, meaning the increase was not big enough to cause concern or to blame the temperature change. This result came was a surprise because the way that these naticids drill holes into their prey’s shell involves a chemical reaction to dissolve the carbonate shell. The cooling temperatures were thought to slow down this chemical reaction hence slowing down the rates of cannibalistic tendencies between these creatures. However, this was not the case, the rates of cannibal attacks remained steady during the cooling event.

Why is this study important?  This study is important because it gives us a better understanding of how climate change can potentially affect species’ behaviors and tendencies. Even though the Falsilunatia’s cannibalistic behaviors were not affected by the cooling temperatures, it still shows some insight on how not all creatures are drastically affected by cooling events. Understanding the correlation between climate change and species behavior can help us gauge what we will expect to see in different animals’ behaviors as today’s climate change is in full effect.

The big picture: This study was set out to find the relationship between an Eocene cooling event and the cannibalistic behaviors of Falsilunatia gastropods. Although finding no direct effect from the cooling temperatures, this is still an excellent example of how we can use the behaviors of ancient creatures and their response to global climate alterations to predict how today’s animals will respond to more recent climate change.

Citation: Dietl G.P., Nagel-Myers J., Aronson R.B., 2018 Indirect effects of climate change altered the cannibalistic behaviour of shell-drilling gastropods in Antarctica during the Eocene: Royal Society Open Science, v. 5, 181446. http://dx.doi.org/10.1098/rsos.181446

A fossil-rich rock formation at the Cretaceous-Paleogene Boundary in Mississippi, USA indicates environmental changes before mass extinction

A fossiliferous spherule-rich bed at the Cretaceous–Paleogene (K–Pg) boundary in Mississippi, USA: Implications for the K–Pg mass extinction event in the Mississippi Embayment and Eastern Gulf Coastal Plain

James D.Witts, Neil H.Landman, Matthew P. Garb, Caitlin Boas, Ekaterina Larina, Remy Rovelli, Lucy E. Edwards, Robert M.Sherrell, J. KirkCochran

Summarized by Mckenna Dyjak. Mckenna Dyjak, who is an environmental science major with a minor in geology at the University of South Florida. She plans to go to graduate school for coastal geology; once she earns her degree, she plans on becoming a research professor at a university. Mckenna spends her free time playing the piano and going to the gym.

What data were used? A fossil and spherule-rich rock formation in Union County, Mississippi exposed by construction. The formation contains the Cretaceous-Paleogene (K-Pg) boundary, which marks the end of the Cretaceous and the beginning of the Paleogene, estimated at ~66 million years ago. This boundary is characterized by a thin layer of sediment with high levels of iridium which is uncommon in Earth’s crust, because it is almost exclusively from extraterrestrial sources.  The K-Pg boundary is associated with a mass extinction: a significant, widespread increase in extinction (ending of a lineage) of multiple species over a short amount of geologic time. The iridium indicates that the extinction was likely caused by an extraterrestrial impact; the spherules found support this idea as well, as spherules are formed from ejecta after an impact. 

Stratigraphic (ordered) section of the rock formation showing the rock units, type of
sedimentology (sand, silt, clay), and fossil type. The K-Pg boundary is marked by the horizontal
dashed line. The black arrows point to calcareous nannofossils and the white arrows point to
dinoflagellate cysts.

Methods: The fossils present in the rock formation were identified and compiled into a complete list. In order to find out the composition of the rock formation. 14 sediment samples were collected; these samples were used to construct a biostratigraphic analysis: corresponding relative rock ages of different rock layers to the fossils found within them. The mineral composition and grain size were determined to construct this analysis. The mineral composition (mineral percentages present) of the sediment samples were determined by using a Scanning Electron Microscope (SEM) and a Diffractometer (type of X-ray). The grain size analysis of the sediment samples was determined by using a sieve (mesh strainer) to sort into different sizes. The Carbon-13 levels of the sediment samples were analyzed: Carbon-13 can be used to determine the amount of plants that were present at the time.The data collected was used to construct the stratigraphic section shown in the figure below.

Results: There was a significant decrease in the amount of micro and macro fossils present. Along with the decrease of fossils there was a positive shift of Carbon-13. The positive shift of Carbon-13 indicates that there was an increase in plant matter buried in the rock record. Sedimentary structures such as weak cross-bedding and laminations (indicates flowing water and fluctuating energy levels) An important layer was analyzed: 15–30 cm thick muddy, poorly sorted sand containing abundant spherules (sphere pieces) that were likely a product of  the Chicxulub impact event.

Why is this study important? The findings suggest that there was a quick, local change in sediment supply and possibly sea level due to the significant variation in facies (body of sediment), fossil changes, and different geochemical data that coincided with the extinction event. 

Big Picture: This study helps us understand how different areas were affected locally before the mass extinction event, which can help us understand how recovery from mass extinctions take place. 

Citation: Witts, James, et al. “A Fossiliferous Spherule-Rich Bed at the Cretaceous-Paleogene (K-Pg) Boundary in Mississippi, USA: Implications for the K-Pg Mass Extinction Event in the MS Embayment and Eastern Gulf Coastal Plain.” 2018, doi:10.31223/osf.io/qgaj

Recently excavated human skulls provide insight into human migration from Southeast Asia to Australia

Somewhere beyond the sea: Human cranial remains from the Lesser Sunda Islands (Alor Island, Indonesia) provide insights on Late Pleistocene peopling of Island Southeast Asia

Sofía C. Samper Carro, Felicity Gilbert, David Bulbeck, Sue O’Connor, Julien Louys, Nigel Spooner, Danielle Questiaux, Lee Arnold, Gilbert Price, Rachel Wood, Mahirta

Summarized by: Lisette E. Melendez. Lisette Melendez is a geology major and astronomy minor at The University of South Florida. She is currently a junior, but has her sights set on going to graduate school for planetary Geology. She loves rocks, space, and everything pink.

What data were used? Newly excavated human remains from three test pits in Tron Bon Lei
(Wallacean Islands, Indonesia) are being compared to human remains from Asia and Australia to test for similarities. Other elements that were found in the excavation include shellfish, fish remains, and fish hooks were used to characterize the living environment.

Methods: This study used dating of various elements and observation of skull traits to estimate ages of the cranial remains. The first element studied was the amount of carbon- 14 in the specimen because carbon-14 can date items up to approximately 50,000 years old. Uranium and Thorium are both elements that are preserved in fossilized teeth and those elements were also measured to reinforce the reliability of the age estimates from carbon. Physical traits of the skull fragments were analyzed to estimate the age and sex of the samples. Age estimation was based on how worn down the teeth were and degree of cranial suture closure (tissues that fuse together as you get older).

The human remains recovered from Tron Bon Lei (Wallacean Islands, Indonesia).

Results: The dating measurements of these Wallacean specimens suggest that the skeletons were buried around 11.5 to 13 thousand years ago, at the end of the Pleistocene Epoch. They are smaller than any of the other cranial remains from Indonesia, Australia, and New Guinea, but the small size of these remains are similar in size to Holocene- age remains, supporting the model that southeastern Indonesian populations were isolated.

Why is this study important? This study helps us unravel the environment of southeast Asia and understand living conditions thousands of years ago.

The big picture: This study shows that the Wallacean islands may be an example of island dwarfing, suggesting that these populations may have been relatively isolated, at least up to the late Pleistocene. Island dwarfing typically occurs when there is a scarce amount of resources on an island, which was only exacerbated by the genetic isolation that occurred on this island.

Citation: Samper Carro, S. C. et al. Somewhere beyond the sea: Human cranial remains from the LesserSunda Islands (Alor Island, Indonesia) provide insights on Late Pleistocene peopling of Island Southeast Asia. J. Hum. Evol. 134, 102638 (2019). Online.

Niba Nirmal, Plant Geneticist, PhD Candidate, Creative

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I’m Niba and I create notes about science (biology, especially plants!) and style (fashion, makeup, skincare)! I write in a physical journal, share photos on Instagram, and create videos on YouTube. I have always loved science – logical thinking, rationalizing answers, learning how to learn—and I also love style—fashion, beauty, skincare, modeling. As a scientist, I am taught logical thinking and rationalizing while cultivating a desire to learn. However, my life as a model is based on fashion trends, creating beauty, and skincare health. For a long time, these concepts existed as incompatible, separate parts of my personality. As I continue my journey as a female scientist and young model, I have integrated the different parts of my life to create my own distinct and compelling self. As I learn more about science and style, I would love for you to join me on my path at Notes by Niba . I’m now modeling, blogging, and beginning my third year as a PhD student studying the genetics of plant development.

I have always loved the process of learning, which led me to the scientific method. The scientific method can be applied to literally everything – working out, training my cat, as well as my experiments in the lab. In lab, I’m discovering how plants express genes to grow and develop. I am trying to understand how a gene control module puts tissues in the right place. This is a huge question in development because proper developing needs careful gene expression in time and space. Because gene networks control every biological process, my research benefits many other fields. For example, many human diseases are caused by impaired networks (ex. Cancer).

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Specifics: My research looks into the SCARECROW plant gene, which forms two tissues – the cortex and endodermis. This is done by a certain kind of cell division, where one cell becomes a cortex cell and the other becomes an endodermal cell. Without the SCARECROW gene, the original cell never divides and is just one fat mutant cell that acts like BOTH a cortex and an endodermis at the same time. Just like how the SCARECROW in Wizard of Oz doesn’t have brain tissue, these plants are also missing a tissue. But we don’t know what the proper SCARECROW expression is to form these two tissues. My research is to determine what kind of SCARECROW gene expression–not just the amount but also at what time–is needed to form cortex and endodermis. By using existing gene modules, I can create different gene circuits to figure out what kind of SCARECROW expression will make the cell divide and get the proper tissues in plant roots. I can see this division in real time in living plants with a super powerful microscope in my laboratory.

Plant research is essential, resulting in drought-resistant food crops, more effective medicines, clothing and fashion, etc. More than 30 THOUSAND plant species are medicinally used (ex. anti-cancer drugs and blood thinners). The world’s food supply is under threat due to population growth, water scarcity, reduced agricultural land, and climate change. As potential biofuels, plants are also important as a potential source of renewable energy. That means it’s critical to be able to detect, learn from, and innovate with our green plant friends. Our past, present, and future depends on plants.

As a scientist, I am pushing the boundaries of what humanity knows – it’s an incredibly fulfilling job and I am grateful for this privilege. 

Keep up with Niba’s updates by following her website, YouTube, or Instagram!

Geology Tour of Washington, D.C.

Image 1: A marble sample with a black stylolite in the right-hand corner, caused by metamorphic stress to the rock. This sample was found in a bathroom in a café in D.C. Finger for scale.

Sarah here-

Recently, I went to the Washington D.C. area to visit the Smithsonian Museum of Natural History (which you can read about here) and to attend a workshop on best practices for new faculty members. But while I was there, I spied some excellent geology right in the city! I already showed you some of those while I was in the museum itself, so I’ll show you some of the other amazing pieces of Earth history that I saw!

I want to remind you that looking at amazing geology doesn’t have to wait for you to be on vacation or in a faraway destination-you can see these sites anywhere, if you’re paying attention! If you want to read more of these types of posts, check out my post from last year on the geology of bathrooms.

Image 2: This is a staircase in the Union Station in D.C.! This is another type of marble, but clearly a very different type of marble than the one we saw earlier.

This first image is of a beautiful stylolite in a marble countertop in the bathroom of a café in the center of Washington D.C. A stylolite is caused when rock, most commonly carbonate rocks like limestone (which we call marble when they are metamorphosed), are put under extreme pressure and the individual grains will compress and leak fluid, leaving behind a squiggly line, like what you see in image 1. Just beautiful!

Image 3: Here’s a granite sample I found on the wall of a building outside. The large crystals indicate that the sample cooled slowly. What I found interesting about this sample is the large presence of the darker colored mineral (amphibole) in the sample! Finger for scale.

Our next stop brings us to Union Station in Washington D.C., where I found this magnificent staircase completely by accident (image 2). I was visiting Gallaudet University and the first signing Starbucks, when I got turned around and ended up at a different Metro station than I had originally intended. Well, serendipitously, I found this absolute beauty, making the detour more than worth it. This rock, just like the image before, is a type of marble, though it has very different colors. The red color in this marble can be attributed to chemical impurities- red is typically what we’d see if iron and feldspar was present in the marble sample. You can also see veins filled with calcite and look like quartz all throughout the staircase! I was intrigued about where this marble came from, so I did a little research. There wasn’t a lot of information, but it seems that this marble likely came from Vermont (See this blog here: https://blogs.agu.org/magmacumlaude/2014/06/13/building-dc-union-station-just-the-floors/), which was created over 400 million years ago, when limestone produced from a shallow sea collided with a volcanic arc and metamorphosed in an orogeny, or a tectonic collision. This is a fairly common scenario with how we get a lot of our marble from the Paleozoic in North America.

Image 4: Here we can see phyllite, a low-grade metamorphic rock as a decorative feature of a wall. Phyllite is easily recognizable by its slight banding (which looks more like waviness when you’re looking at this particular rock) and the glittery sheen to it, given by the muscovite mica which develops during the metamorphic process.

Our tour continues to just outside of Washington D.C., to Arlington, VA, where I was visiting a friend in the area. As we were walking to breakfast, I was treated to a spectacular number of rocks featured in the buildings’ walls along the way. First, is a beautiful granite (image 3). The pink mineral is potassium feldspar (K-spar, for short), intermixed with the milky white mineral (quartz) and a lot of amphibole, the black colored mineral that’s heavily present on the left side of the block. Granite also usually contains biotite, a black mica.  If you take a look at this granite, you’ll see that the individual crystals are quite large, which tells us a lot about its formation. It’s telling us that it was formed intrusively; meaning, it was formed in an area not exposed to Earth’s surface and it cooled slowly, giving the crystals time to grow. I stopped to take a photo of this because the amphibole (there are many varieties of amphibole-hornblende is the most common in granite) because the heavy presence of the swirling amphibole isn’t something I usually see in most granite samples. Second, I saw these gorgeous phyllite samples on the outer wall of a building (image 4). Phyllite is a low-grade metamorphic rock, which means it’s not exposed to extremely high amounts of heat and pressure, but it has undergone significant changes from its protolith (otherwise known as its parent rock). In the case of phyllite, its protolith was a shale (compacted mud). You can recognize phyllite by a few different characteristics. During the metamorphic process, muscovite (a soft mineral in the mica family) develops, giving phyllite a really lovely shiny appearance (you can think of mica as being like nature’s glitter; just like glitter, mica is nearly impossible to completely get rid of if you accidentally get it everywhere!). You can also recognize phyllite by the gentle bands that form. Many metamorphic rocks are foliated, which we can think of as banding across a rock. The more pronounced the banding usually indicates a higher amount of metamorphism applied to the rock.  Phyllite has subtle banding, which indicates that lower amount of metamorphism.

So, this next image (image 5) isn’t in D.C., but it was found during this trip in College Park, Maryland on the University of Maryland’s campus. It’s another gorgeous example of granite, this time in a fountain. Sometimes it can be really hard to recognize rocks when you’re used to seeing them beautifully polished and sealed (like the granite in image 3, but you can definitely do it with practice!) Just like in image 3, if you look closely at this fountain, you’ll see large crystals, because it’s an intrusive rock, and the same types of minerals- our pink K-spar, milky quartz, and black amphiboles. An intrusive magmatic event from millions of years ago had to form and cool, and then that granite had to be exhumed (brought to the surface) for someone to make that fountain. So cool!

Image 5: A fountain on the University of Maryland’s campus made of unpolished granite. You can tell its granite by the types of minerals in the rock (quartz, K-spar, and amphibole) and the larger crystal grains that make up the fountain!

Last, but certainly not least, let’s look at the marble here in the Ronald Reagan airport (image 6). This gorgeous marble makes up part of a seafood restaurant right near the entrance to the airport, before you go through the security line. Sorry that the image is kind of far away, but this was the closest I was able to get before having to get through the security line! One of my favorite things about marble is how different it can look from sample to sample. This marble shows completely different features than the ones I showed in images 1 and 2-remember, the color of marble is driven by chemical impurities. You can see large scale veins of what is likely calcite all over the rock itself as well as some dissolution features on the left side.

Image 6: Marble being used as the wall around the elevator shaft in the Ronald Reagan Airport. This marble shows large veins and dissolution features that we didn’t see as much in images 1 and 2!

Research Trip to the Smithsonian

Sarah here-

Recently, I went to the Smithsonian Museum of Natural History for a few days for some research (image 1)! This was an especially exciting trip because I got to see the BRAND-NEW Fossil Hall exhibits that the curators and staff have been working on for years (image 2)!!

My main goal for going to the collections was to make a personal database of the specimens present at the Smithsonian that belong to the groups I’m currently working on, echinoderms called Diploporita and Rhombifera and make notes of my own for future projects I’d like to start. For example, many of the specimens at the Smithsonian had unusual preservation, so I was thinking about possible projects for myself and for future research students to look into why these fossils were preserved the way that they were. I took photos of many of the specimens so that I’d have a good reference for later, too (image 3).

Image 1. Here I am with my visitor’s badge! This badge lets me get into the collections areas.
Image 2: This is an advertisement for the brand-new Fossil Hall at the Smithsonian on the side of a bus stop on Constitution Avenue in Washington D.C.
Image 3: This is a typical setup for fossil photography. I was taking photos of a fossil called Holocystites, a common echinoderm fossil from Silurian rocks of Indiana.

My main goal for writing this post, however, is to show you what it’s like to work at a museum! Museums are amazing places to go and learn and have fun, but it’s a totally different experience to go to a museum to look at its exhibits, as opposed to going to look at the collections. The exhibits at the Smithsonian, the halls filled to the brim with amazing rocks, fossils, and artifacts, only make up a teeny tiny percentage of what’s actually stored in the museum. So, without further ago, here’s the behind the scenes tour!

So, while the exhibits are absolutely beautiful and show off magnificent tales of Earth’s history, the collections areas show off something completely different but equally beautiful: the rows and rows of cabinets that are chock full of fossils just waiting to be studied (Image 4)! Every time a scientist publishes a paper on a fossil, that fossil has to be put in a public museum so that it can be studied by other people in the future (this isn’t always true, but almost all journals require that you put your fossils in a public museum). Some of the fossils in those collection rooms are absolutely beautiful and totally worthy of being put in an exhibit (image 5), but so many more, while they aren’t as “perfect”, give us insight into scientifically interesting questions.

Image 4: Look at these cabinets! Each drawer is FILLED with fossils! This is just one of the many rows of echinoderm fossils.
Image 5: Just look at this gorgeous crinoid fossil!!! This crinoid (called a sea lily) belongs to Echinodermata, the group that includes modern day sea stars. One of these fossils was likely made during a storm event, where a living creature was buried alive quite suddenly- it’s how we see such beautiful preservation of its many body parts.
Image 6: This exhibit shows how echinoderms have modified their ability to attach to surfaces and feed throughout time, from over 500 million years ago to modern day!

 

 

 

 

 

 

 

 

 

 

 

Now, I want to show you a little bit about the Smithsonian’s exhibits! I want to show you my favorite new exhibit. You guessed it-it’s about echinoderms! This new exhibit shows the changing body types we see in these fossils throughout geologic time (image 6). They also did some really great work on an Ice Age exhibit and the megafauna that lived there (like mammoths, the Irish Elk, large sloths). It was tied in really well with learning about how climate change has affected life on Earth in the past and life on Earth now!

Finally, I want to show you around the exhibits you might not have noticed at the Smithsonian- the floors and bathroom counters! Since this is the nation’s most famous natural history museum, you know they have to have some good geology in their building materials! The main staircases that run through the museum are marble (metamorphosed (meaning, it was put under a lot of heat and pressure) limestone). Marble often leaves us clues about how it was metamorphosed by leaving behind stylolites. Stylolites are deformation features-meaning, the marks that rocks leave behind when they’re being squished by geologic processes. They often look like little squiggly lines! Check out the epic stylolites in the marble staircases of the Smithsonian (image 8)! Finally, here is a column that is made out of a rock called a metaconglomerate, which is a metamorphosed conglomerate (image 9). To put that into normal words, a conglomerate is a sedimentary rock that’s made up of large pieces of material (like pebbles or larger) all jumbled together. A metaconglomerate is simply one that has been deformed from heat and pressure! You can tell that this column been metamorphosed by how the large pieces of rock look like they’ve been stretched out and bent in weird directions.

Image 7: Here is the ground sloth they have on display! Ground sloths are some of my favorite non-echinoderm fossils. It’s hard to comprehend just how big they were, especially when you compare them to sloths today!
Image 8: Here are stylolites from the staircases of the museum! My foot for scale in the bottom corner.
Image 9: A column made up of metaconglomerate, which is a conglomerate that’s been subjected to heat and pressure. Bonus: look at the floors this column is sitting on top of! Gorgeous!