An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics
Caleb M. Brown, Donald M. Henderson, Jakob Vinther, Ian Fletcher, Ainara Sistiaga, Jorsua Herrera, Roger E. Summons
Summarized by Time Scavengers contributor, Maggie Limbeck
What data were used? The holotype specimen (fossil or other specimen that all others are compared to to determine what it is) of Borealopelta markmitchelli was used for all experiments touched on in this article. Data was also collected from other members of the Ankylosauria (armored, herbivorous dinosaurs with a club on their tail) clade for comparison.
Methods: A phylogenetic analysis (family tree) was completed using this new dino as well as others from the Ankylosauria and Nodosauridae (Ankylosaurs missing the club on their tail) clades to determine where in the dinosaur tree B. markmitchelli belongs. This also provided data for comparison in life habit and some of the unusual features of this particular dinosaur. Additionally, geochemical studies were done on this specimen, including scanning electron microscopy (SEM) and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). Both of these methods were used to get an idea of what the preserved organic material on the specimen was and determine what kinds of fossil melanins (pigments) were present.
Results: The resulting phylogenetic tree from this study does place B. markmitchelli where one would expect it to go within the Ankylosauria tree (within the Nodosauridae clade). The TOF-SIMS experiment showed that there were ions present that indicate benzothiazole and therefore pheomelanin was present. These particular chemicals would indicate that parts of this dinosaur were reddish-brown in color. However, not all parts of the osteoderm (bony skin) and epidermal coverings (scales) show this reddish-brown coloration.
Why is this study important? This study is important because it highlights how much we can learn from one extremely well preserved individual fossil. It was used in a phylogenetic analysis to determine where it belongs in the dinosaur-scheme of things, images were taken of the skull, and geochemical data was returned to determine the coloration of the skin. From these studies the scientists were able to determine that these dinosaurs used camouflage to help protect them from predators. This is very different from what we see today in predator-prey interactions. Borealopelta markmitchelli was by no means a small dinosaur (~5.5m long and ~1,300kg) and had significant body armor yet it still needed camouflage. Today, large mammals comparable to this size do not need camouflage because even the fiercest predator does not go after grown adults. This new relationship between Cretaceous predator and prey highlights major differences in large predator-prey interactions through time. This specimen will continue to play a major role in research for years to come.
The big picture: There are really two big picture things to take away from this article. The first being that science, and ground breaking science in particular, is always interdisciplinary. These paleontologists relied on geology, biology, ecology, and chemistry (to name a few) to come to their conclusions about B. markmitchelli. This is really important because people always think that science is very isolating and you only work on your own, when in actuality science is accomplished by a team of people who can support you and fill in knowledge gaps. Second, it is important to look into those flashy science articles that pop up on your newfeeds and on Twitter. Those articles are press releases to get you interested in the science that is being done on these fossils or rocks or bacteria. We scientists get excited about our work and want to share it with people-take the time to do so, get excited about nature, and keep reading!
Citation: Brown et al., An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics, Current Biology (2017), DOI: 10.1016/j.cub.2017.06.071
“Let me get this straight: You are a Biology major that takes Geology classes, and you work for Chemistry?” A friend said that to me many years ago. It seemed funny back then, but it still true. I have always loved the natural sciences, and my experiences as a student and as a college instructor have allowed me to participate in these three fields.
My research involved studying the relationships between sediment types, burrowing animals, and the burrows shapes that they make. Although this may like a strange topic, consider this: Insects and mammals can’t burrow into groundwater (water stored in sediment underground), so their burrows stop at the water table (the boundary between dry soil and water-soaked soil). Many plants cannot live if their roots are submerged, so the roots also stop growing at the water table. Because roots and burrows can be preserved in the fossil record, they can be used to determine past climate conditions. For example, if a paleontologist finds that roots and burrows found in a rock layer all have the same depth, then there was groundwater in the past. In addition, the paleontologist could determine that 1) there was enough precipitation to allow water to soak into the ground, 2) there is enough accessible water for an ecosystem to live, and 3) there may have been a river or lake nearby as the water table is near the soil surface.
Burrows, tracks, trails, and root casts are called trace fossils. Trace fossils can also be used to determine what organisms were present in an ancient ecosystem, how diverse the organisms were, and what environmental conditions were. Much of this work is done by studying actual burrows produced in the field and in the laboratory. My work involved allowing trapdoor spiders, wolf spiders, and tarantulas to produce burrows in the lab. After moving the spiders into a new habitat, I poured plaster into the burrows and measured the dried casts.
One of the big goals of our lab group is to determine the relationship between burrow-shape and burrow-maker. Several arachnid species have been studied in this lab: scorpions, whip scorpions, and spiders. We have found that although these groups are closely related, they all produce very different burrow shapes, and that shapes appear to be related to the behavior of the species as well as its body shape. My favorite part about being a scientist is seeing something that may be mundane and knowing there is a complex story behind it. For example, a piece of limestone used to line a flower bed represents a past environment, the skeletons of small organisms, and the transport of chemical elements from the continents to the oceans.
For the past few years, I have focused more on teaching than on research. I have been lucky enough to teach at three universities in both chemistry and geology. I have worked with many kinds of students, both science and non-science majors. Much like Time Scavengers is addressing, I have found that many of my students have very little interest in science or think that they can’t understand it. In my classroom, I encourage students to find relationships between the material and their daily lives. Although I have enjoyed my research programs and am proud of my work, I have decided that education is my real strength. I am starting a licensure program this fall to earn my teaching licensure for high school earth science and life science. I hope that my research experience and multidisciplinary approach will encourage all of my students to appreciate the natural world and never stop learning about it.
For people wanting to become scientists, I want to offer two pieces of advice: 1) All of the sciences intersect in some way, so don’t despair if you have to study one you hate to get to the one you love, and 2) The more experiences you have, the better prepared you will be for a career or in graduate school. Find ways to become involved in research or outreach. Apply for internships, even if they don’t pay!
Mike helped lay the ground work for developing a website on their lab’s ichnology projects called the Continental Neoichnological Database. Click here to learn more about the database.
All of us have taken wildly different journeys to get to where we are today. I’d like to share part of mine with you all and emphasize the importance of undergraduate research. Although I am currently in a geology PhD program I started out as a Biological Sciences major. When I started my undergraduate career I wanted to become an orthodontist – this slowly changed to medical examiner to I have no idea. The spring semester that I was supposed to graduate I took a course in the Earth and Environmental Science Department to fulfill my last 300-level course requirement. The course was “Introduction to Paleontology” with Dr. Roy Plotnick. I immediately became enamored with the content and scheduled a meeting to talk with him. He offered me a research assistant position to work in his lab and I accepted. I decided to stay for an additional year to get a minor in Earth and Environmental Science.
I did not know much about undergraduate research when I started out my new position as research assistant. Roy had several projects going on at the time. I started in on one working to assess how a specific type of brachiopod interacted with the seafloor. This involved me using a force gauge to measure the amount of force required to push the creature into various types of sediment. I also explored a specific type of crinoid holdfast (the part that secures them to the seafloor) and how it acted almost like an anchor. Roy gave me the freedom to explore the experimental process. He had a variety of tools and materials to experiment with and I was able to build different types of holdfasts and use the force gauge to drag them through different types of sediment. This was not only fun but it was a huge boost in my confidence. I was conducting my own experiments and collecting data.
I decided I wanted to go to graduate school in paleontology. I had become very interested in the extinction dynamics of the Late Devonian. I did an independent study with Roy examining the changes in cephalopod diversity during this dynamic time. I began applying for graduate school in all the wrong ways. I attempted to contact faculty members but they weren’t very good at emailing me back so I would go ahead and apply rather than attempt to contact them again. This mostly resulted in me losing a lot of money on applications. Many of the faculty I applied to work with simply had no funding for students that year. One day Roy brought in an article that was recently published in GSA Today by Dr. Alycia Stigall. This article was titled, Speciation collapse and invasive species dynamics during the Late Devonian “Mass Extinction” and, of course, sparked my interest. I exchanged several emails with Alycia before applying (late) to her program. A few months later I was accepted to work with Alycia for the fall of 2012. Thus, beginning my long journey through graduate school. Without the random chance encounter with Roy during my undergraduate career, I would not be where I am today. His encouragement, support, and enthusiasm provided the best working environment for me to officially become a scientist.
Not all undergraduate research experiences result in positive experiences as mine did. By reaching out to faculty members and participating in different research projects you will quickly find out what you like and dislike! There is no harm in talking to faculty or graduate students about your research interests. It is very likely that they have similar interests or know people that do.
I recently returned from a five-week field camp in Scotland. Field camp is a course that most geologists participate in that is intended to teach students how to collect geologic measurements in the field, recognize geologic structures like folds and faults, understand age relationships of the rock, and ultimately make sense of all of this by making maps and cross sections (interpretations of what the surface geology looks like underground). Field camps are incredibly important as geology students because it reinforces the ideas that the best geologists are those that have seen the most rocks and that geology needs to be learned outside, not just in the classroom.
So, why Scotland for field camp? Scotland is an interesting location geologically, because for much of Earth’s history it was essentially a ping pong ball with sections of the country getting added on by collisions with other continents as it bounced around. If you look at a map of Scotland you can see two almost parallel lines dividing the country into three pieces (Figure 1). The top most fault is the Great Glen Fault which runs through the city of Inverness and Loch Ness (where the Loch Ness monster resides). The fault further to the south is the Highland Boundary Fault which does divide the country into the Highlands and Lowlands. Each of these pieces was accreted (added on) during a different collisional event. Surprisingly, the last, and youngest, collisional event that happened, when Baltica (Northwestern Europe) collided with Laurentia (North America, Greenland, Scotland), deposited the oldest rocks that you can see in Scotland. These rocks are ~3.2 billion years old and they lay on top of limestone that is ~540 million years old (Figure 2). Seeing this age relationship in the field tells us that something crazy was happening geologically!
Field camp is a lot like summer camp mixed with a typical college class-there is a lot of fun to be had with fellow rock nerds, but also a lot of learning and homework to be done. On a typical day we would leave our hostel or house by 8:30am, work in the field, mapping and collecting data, (either in small groups or individually), leave the field around 5pm, go home and cook dinner for your small group, then work on interpretations of our data and prettying up our maps. Usually at the end of the week we would have a larger project to hand in based on the maps that we had made that week and our interpretations of the area (Figure 3).
Going to field camp can seem daunting at first, especially if you are going on one outside of your home country, but truly is an important experience in learning to be a geologist. Like practicing a sport or instrument, you have to practice geology skills in order for them to become second nature and field camp is the best place for that practice. For a lot of people, this is where geologists have their first “I am a geologist” moment. So, for anyone who wants to be a geologist (or paleontologist or other earth scientist) get outside and look at some rocks and fossils and start observing, because the best geologist has seen the most rocks!
Maggie and I recently traveled to Clayton-Bradley Academy to explore fossils and different animals with pre-K students. We have a set of fossils we usually bring with and a guideline of topics to hit with various age levels but planning for pre-K never works out!
We tried to keep it simple and hands on. Each of the samples we brought with us was relatively large and the students were able to touch everything. We first showed them a sample of Lepidodendron – which is often mistaken for scales or dinosaur skin. We discussed how it was a plant, what the shapes meant, and how there is no plant material left.
We then examined various teeth and had the students compare them to their own teeth. The students could feel in their mouth and find the sharper versus flat teeth to compare to the fossils that they were exploring. We had a large mammoth molar that we passed around and most of the students thought that it was ribs from an animal. We oriented them and told them it was actually a tooth and to think about what sort of animal would have a tooth that big today. Younger children often have difficultly connecting words/names with the actual animal so we brought with images of these animals to help visually remind the students of what we are talking about. They couldn’t come to the conclusion of mammoth on their own but once we showed the image they remembered a similar animal from movies (mostly Ice Age) and you could see the wheels turning. It is always an adventure traveling to new schools and interacting with different age groups. It really tests your ability to modify your vocabulary and thought process.
As a paleontologist I study the evolutionary relationships of ancient echinoderms (relatives of modern day sea urchins and sea stars). To accomplish this, I use morphological characters (shape and other data points measured on a fossil) to create a phylogenetic tree, or evolutionary hypothesis about the relationships and relatedness of groups of echinoderms. Currently I am working with a group of echinoderms called Paracrinoidea and I am trying to create a phylogenetic hypothesis for the group.
The paracrinoids missed the memo on how to be an echinoderm and are completely asymmetric (while other echinoderms exhibit some sort of symmetry) and have other unusual morphologies for their feeding structures. Because of these unusual characteristics paracrinoids have not been able to be placed into an evolutionary hypothesis and are therefore unable to be used to answer any other evolutionary questions that we may have. My research will allow this group of echinoderms to be better understood and eventually be used in other evolutionary studies. Additionally, because my research is based in understanding evolution I am able to use my organism as well as other organisms to help teach others about the concept of evolution and organisms and the environment changing through time.
My favorite part about being a scientist is getting to teach others science. I am very passionate about scientific education and outreach. I have always remembered sitting in my eighth grade science class and seeing my teacher be so excited to teach us about rocks and minerals and that excitement and wonder about the world around me has never changed. As I continue my education in geology I have come in contact with many professors who are just as excited about science as my 8th grade teacher was and their passion for teaching has impressed upon the importance of being excited about science education. I aim to be able to continue to teach and do science outreach throughout my career as a scientist to spark the same passion for science that my teachers have instilled in me.
For all of the young scientists out there, the best advice I can give you is to just go for it. If you are still in high school don’t be ashamed to like science, because science is really awesome! Take some time to get familiar with the basic concepts of whichever discipline you enjoy, search out articles that interest you, talk to your teachers about ways they can help you continue to learn more. If you are in college look for internships, talk to professors about doing an independent study on topics you are interested in, get involved in a research project with a professor. If someone tells you can’t do this or that it’s too hard of a field to get into, don’t listen to them if it is really what you want to be doing. Science is hard, I can’t lie about that, but it is also so rewarding if you are willing to work hard and just go for it.
Sarah here –
If you’re applying to graduate school, have recently started, or are even a year or two into your program, I’m sure you’ve gotten tons of advice from professors, current students, the internet, random strangers, all over. I hope you’ll read this, anyhow-I hope that my advice will be a little different from the others from whom you’ve already listened.
1. Find friends (and colleagues!) From the minute you step into higher education, it can feel very isolating. You take classes with the same people; you research with an even smaller group of people; often, you don’t even know other graduate students from outside your department. It’s a big change from undergrad to grad school, for sure, and even more than that, oftentimes, graduate students are pressured to compete with one another. It’s the sad truth, but there are limited resources-your advisor’s time, grant money, etc.-our first instincts are to compete with everyone around us to get ahead. In reality, there will always be a little bit of competition, no matter what. But what is often missed is that graduate school doesn’t have to be this a lot of the time-nor should it be. You’re surrounded by some of the best and the brightest around. Why not take this opportunity to learn from them?
If I had to pick the most important relationship I made out of graduate school, it wouldn’t be with my advisor, with my committee, or with contacts I made at conferences. It was my labmate, Jen. She and I traded every single piece of our written work back and forth and we edited them mercilessly until they were flawless-grant proposals, emails, papers, job applications, you name it. We encouraged each other through all of our applications, even though we applied to all of the same ones-and many times, one of us was chosen while the other wasn’t. We’ve come up with research project ideas for the other, and some that we could collaborate together on. While we were competing for the same grants, we never actively competed against one another and put the other down. As a result, I have a wonderful friend, an editor, and an irreplaceable research collaborator, all in one. When graduate school felt unbearable, I’d turn to Jen for help, and without fail, I’d feel like I could handle it again. This relationship is so important; academia is hard. You need someone that you can trust and someone who can remind you of how far you have come-everyone needs some kind of support-don’t struggle by yourself. Everyone is struggling, even if they don’t say it. Be that uplifting person for someone else-be humble, be kind, and build a supportive community for you and your fellow classmates.
2. Find a hobby! Many of us feel like hobbies take away from the whole reason we’re in graduate school-to learn! We need to read papers and research and teach (and sleep-but only if we’ve finished work!). This is probably the worst thing you can do for yourself. Grad school is isolating enough-don’t further push yourself into a bubble. Find a hobby-a club, a new sport, anything-to join. Go every week. Don’t make exceptions, even if you feel like you’re just too busy-make your one or two hours a week just as mandatory as your classwork. Make friends outside of your department and even-dare I say it?-outside of academia! I didn’t do this during my master’s degree-I spent two years at the office from 7AM-9PM most days (including the weekends). I was lonely, miserable, and as a result, I don’t think I performed as well as I could have. During my Ph.D., I took up Middle Eastern dancing-once or twice a week-I made many new friends, learned a new skill that had nothing to do with geology, and most importantly: it gave me something to look forward to every week: a reward for surviving another week of graduate school. My second hobby, which wasn’t something I did in a group, but was so healing all the same: reading for fun. I made both of these a priority during my Ph.D. I read for fun 15 minutes a night before bed (yes, even on nights I went to bed at 4AM) and always went to dance class. You’d be surprised what having hobbies can do to restore your happiness and sanity.
3. Do some outreach! I’m a paleontologist-this means that I get to spend my days talking about dinosaurs and playing in the dirt (even though I don’t study dinosaurs). This means that I’ve been lucky enough to be invited to talk to countless K-12 classrooms and to fossil collecting clubs. A lot of people view this as a waste of time, that it might take away precious time from research-sure, you could look at it that way. But here’s what I got out of it: by all of these interactions-from working with girls’ after school groups to teach them confidence, to talking to families about the rocks they had collected, I learned to talk about my science in very understandable terms to all kinds of people. Communication isn’t a very easy skill-many of the scientists I meet at conferences, even scientists within my discipline, have a hard time explaining their research, even to other scientists. We forgot that if other people can’t understand your work, you’re not doing the best job that you can. My work with kids and non-scientist adults has given me so many opportunities to try different explanations and pictures so that I can talk to just about anyone about what I do-this has even helped me learn how to speak to scientists outside of my discipline. Also, consider what got you interested in science-a lot of us will remember learning about dinosaurs or volcanoes or something that really excited you. When you talk to these kids, you’re showing them that they, too, could become the next generation’s scientists. If you’re a woman, or a person of color, a veteran, a person with a disability, or someone who is LGBT-this can mean even more to kids who might not have had any idea someone like them could ever become someone like you. So go call an elementary school or find a local group that you can go share your love of whatever it is that you study-it will make you a better communicator and you might just be the inspiration for the next amazing person in your field. I know when I’m stressed or even sometimes really considering whether I made the right career choice (who hasn’t wondered that in academia?), being able to share my love of fossils with people who think dinosaurs are just as cool as I do is one of the best things to remind me that I am doing the thing I love most on Earth. Share your passion! You won’t regret it.
Grad school can be an amazing experience, as much as it can be a very stressful one. Remember to take time for yourself, share your love of science, find colleagues that support you, and try to be that uplifting person for someone else. It’s worth it.
Camilo Mora, Benedicted Dousset, Iain R. Caldwell, Farrah E. Powell, Rollan C. Geronimo, Coral R. Bielecki, Chelsie W. W. Counsell, Bonnie S. Dietrich, Emily T. Johnson, Leo V. Louis, Matthew P. Lucas, Marie M. McKenzie, Alessandra G. Shea, Han Tseng, Thomas W. Giambelluca, Lisa R. Leon, Ed Hawkins, and Clay Trauernicht
Data: This study was conducted by gathering data from previous studies and looking at the number of lethal heat events that have occurred around the world from 1980 to 2014. The study also estimates the percentage of the population that is at risk from increased air temperatures and humidity due to human-induced climate change in the future.
Methods: The authors used data from 911 previous studies to use in their analysis. They collected information on the place and dates of lethal heat events, or extreme heat events that led to human deaths. The number of days per year that surpassed the heat threshold for which humans can live in was assessed for each year (1980-2014). To determine how much of the population may be at risk of heat-related deaths in the future, the scientists used four different CO2 scenarios to model air temperature and humidity to year 2100.
Results: From the previous studies, the scientists found 783 cases of human mortality linked to excess heat from 164 cities in 36 countries. Cases of heat-related deaths were concentrated to mid-latitude regions, with high occurrences in North America and Europe. Temperature and relative humidity of an area were both found to be factors important to identifying regions where climate conditions may become deadly, as these are related to human’s ability to regulate their body temperature. Currently, around 30% of the Earth’s population is exposed to climate conditions that are considered deadly. By the year 2100, this number is projected to increase to 48% under a CO2 scenario where emissions are drastically cut, and 74% under a CO2 scenario of increased emissions.
Why is this study important? This study highlights the health risks posed to humans due to increased heating of the Earth. Several countries and large cities, mostly concentrated at the mid latitude regions and equator, are at most risk.
The big picture: Under all emissions scenarios, whether we cut emissions drastically or keep emitting CO2 at the same rate, an increased percent of the human population will be at risk of heat-related deaths. This study emphasizes the importance of aggressive mitigation to minimize the human population’s exposure to deadly climates linked to human-induced climate change.
Citation: Mora, C., Dousset, B., Caldwell, I. R., et al., 2017. Global risk of deadly heat. Nature Climate Change, 7, 501-506. DOI: 10.1038/nclimate3322
As a paleontologist I study how fossils are preserved in the fossil record (taphonomy), and how morphology changes within species across space (geographically) and through time (stratigraphically) in response to several processes such as ontogeny (development) and environmental change.
As a Curator in a museum, I use my research to teach our community about the process of science and why paleontology and geology are important to our society today. I am also very passionate about public science literacy, and am involved in educational program and exhibit development as well as lecturing on a variety of science topics in geology and paleontology.
My research is specimen-based, and requires a lot of intensive fieldwork. This is fantastic for me, because I love to be outside and being active. I get all of the trilobite specimens for analysis by hammering them out of the rock layers. I then bring them back to the laboratory where I prepare them out of the rock, photograph and measure them, and then conduct my mathematical modeling and statistical analyses to test my hypotheses and answer my questions (while generating new ones!).
Understanding the biotic response to climate change is crucial for our society, especially in the face of our current climate crisis, but modern biological studies are not long enough to document the long-term impact of these changes. The fossil record is an excellent resource to study species’ response to environmental change over the long term because it shows us the consequences of previously run climate change “experiments” in Earth’s history. My research shows that trilobite populations can track their preferred environment over millions of years and through constant climate perturbations rather than evolve new adaptations or go extinct. This response is consistent with many other examples in the fossil record and shows us that migration is a viable and successful response to climate change for many species.
My favorite thing about being a paleontologist is that it is the closest thing to time travel that we have. When I am in the field, I am looking at fossils that take me back 450 million years in Earth’s history, and I am usually the first person ever on Earth to have seen and collect these fossils. The fact that I am traipsing around an ancient ocean that once covered most of the United States still blows my mind. As a scientist in a museum, I also enjoy teaching the public about the amazing planet we have and the relevance, to their lives, of the world-famous paleontological resources in their back yard. There is nothing more rewarding than a child in awe.
Whatever path your career takes you on, be passionate about it. Whether you want to be a paleontologist, another type of scientist, or pursue a non-science career, if you are passionate about what you do, you will never feel like you are going to work. I look forward to what every day brings because every day is different.
Adriane here, reporting once again from the beautiful Tasman Sea!
You may recall from my previous post that I am currently sailing the RV JOIDES Resolution (the JR), a research vessel equipped with a drill rig that is used for scientific ocean drilling. During these scientific expeditions aboard the JR, a team of about 30-35 scientists and several crew members (the JR can hold a maximum of 130 people) drill sediment from the seafloor. Everyone on the ship has a job to do, and in this post I’ll explain what my role is while sailing in the beautiful Tasman.
I am sailing as a planktic foraminifera biostratigrapher (click here to learn more about what that means, and here to read more about how we use fossils to tell time) or someone who uses fossils (‘bio’) to tell time from the rock record (‘stratigraphy’). Altogether, there are 9 paleontologists on the ship. Some of us are here to tell the other scientist what age the sediments are that we’re drilling into, and some are using fossils to interpret paleobathymetry, or the water depth of the Tasman Sea at different times in Earth’s history.
Every scientist’s role on the ship is vastly important, but the first thing everyone wants to know as sediment cores are being drilled and brought onto the ship is how old this sediment is. This is important for a few different reasons: 1. There are specific intervals in Earth’s history that we (the scientists on the ship) want to drill into; 2. With age, we can tell what was going on in the geologic past in the Tasman Sea and further interpret the plate tectonic movements and environments when the sediment was deposited, and 3. We can modify our drilling plan including changing out the drill bits, slowing down the drilling, or speeding up the drilling process to best capture key intervals in Earth’s history. Thus, being a biostratigrapher is initially a very important job, and one that can affect the drilling operations on the ship. That’s why there are four main fossil groups that we use to tell time: the calcareous nannofossils (which are REALLY tiny), the planktic (and in this case, the benthic) foraminifera, siliceous radiolarians, and pollen spores. All of the fossil groups are important to have, as there are intervals in the cores where one or two fossil groups may disappear, or there may only be planktic foraminifera in one sample, etc.
But enough about biostratigraphy, now to show and tell you the entire process we go through when we receive a core on the ship!
The first thing that happens when a core is pulled up onto the core deck is that an announcement is made, such as ‘Core on deck!’. I then put on a hard hat and safety glasses and grab a bowl to collect the core catcher sample (the end piece of the core that literally keeps the sediment in the pipe as the core is brought back to the surface). The core catcher sample is the very last 10 centimeters of the core that is given to the paleontologists to analyze for age. The technicians bring the core from the drill floor to the core deck, where the core is cut into sections. While the core is being cut, another technician is given the core catcher to disassemble, remove the sediment, and give to the paleontologist.
Once I have the sample, I take it back inside to process. If the sediment is very soft, I simply rinse it over a screen to remove small particles (refer to my previous ‘From Mud to Microfossils: Processing Samples’ post). But recently on the expedition, the sediment we are recovering has been very hard. In this case, the core catcher sample is cut into thin slices using a rock saw, then small pieces are shaved off of a slice using a sharp-edged tool. These smaller pieces are crushed with a mortar and pestle for a few minutes.
The sediment is then rinsed over two screens: a 2 millimeter (mm) screen to hold back the larger particles, and a 63 micrometer (μm) screen to catch the microfossils. The >2 mm rock pieces are then crushed again until there is enough particles in the 63 μm screen to analyze for planktic foraminifera. The sediment, which we call the residue at this point, is then put into filter paper on a stand to drain out the extra water. The filter paper and residue are then put onto a hot plate to dry (yes, there have been a few times when the paper has burned!).
After the residue is dry, it is put into a small plastic bag with a label indicating exactly where it came from within each core. At this point, the residue is ready for analysis! At my desk, I have a microscope, a small tray, very small paintbrushes for picking very small fossils, a jar of water, and green food dye. Because the microfossils that I look at are made of calcite, they are very bright under the lights in the microscope. Dying the fossils a green color cuts down on the reflectance of light off the foram’s shells, and enables me to see the details of the fossil necessary to identify it to the species level.
There are usually many different planktic foraminiferal species in each sample, but there are only a few that I usually look for that tell me about the age of the sediment. These are called ‘marker species’. The geologic time at which a marker species evolves or goes extinct has been calibrated by previous scientists before me over several decades, so when I find a species, or when a species suddenly disappears, I have a chart that I use to look up when that speciation or extinction event happened.
Once I have a datum (reference point of time) and an age estimate for the residue sample I’m looking at, I write this information on a big white board in the paleontology lab. All of the other scientists look at this board frequently to determine the age of the sediment that is being brought up.
Education and Outreach Aboard the JR
Every IODP expedition has an education outreach coordinator that sails with the crew and scientists. This person’s job is to blog, post photos on social media outlets (Facebook), and conduct ‘Ship to Shore’ linkups. These are scheduled events with colleges, university, and K-12 schools where the education outreach coordinator gives the viewers a live tour of the ship and the activities that are going on. Because every expedition is funded by public monies from several countries, it is our responsibility as scientists to engage with the public and tell you all what we’re doing and what we’re learning. I’ve participated in a few ship to shore linkups already, and have really enjoyed talking with students of all ages about fossils, what we’re finding in the Tasman Sea, and how we use the fossils to tell time!
If you are an educator and want to participate in a Ship to Shore video event, click here to sign up!