Geologic evidence for changes in paleoclimate on Mars

Dichotomies in the fluvial and alluvial fan deposits of the Aeolis Dorsa, Mars: Implications for weathered sediment and paleoclimate
by Robert E. Jacobsen and Devon M. Burr
Summarized by Time Scavengers contributor, Rose Borden

What data were used? In this study, the scientists used images and topographic data from satellites orbiting Mars. This data was collected using two instruments:

CTX (Context Camera) images from the Mars Reconnaissance Orbiter were used to map the locations and types of fluvial and alluvial (formed by flowing water) geologic features in the study area. Images from this camera can resolve features about the size of a room (5-6 m or 15-20 ft).

MOLA (Mars Orbiter Laser Altimeter) topographic data from the Mars Global Surveyor was used to find elevations of the different features that were mapped and infer their relative ages. For example, if one feature is on top of another, the higher one is inferred to be younger.

Methods: The authors made a geologic map of the Aeolis Dorsa region using images from thes two datasets described above. The Aeolis Dorsa region is a rectangular area roughly 500 x 500 km. There are many types of sinuous (snake-like) ridges in this area that were formed by wind depositing or eroding the sand and rocks, by flowing water, or by tectonics. Some of these sinuous ridges are interpreted by geologists as inverted fluvial and alluvial deposits. Fluvial refers to transport by rivers or streams and alluvial refers to transport by intermittent water, such as on a floodplain. These types of features are formed by water carving out a river channel and depositing rocks and sediments within that channel. When the water dries up, these rocks and sediments become hardened by a process called chemical cementation, which means the rocks and sediments are “glued” together chemically by minerals dissolved in the water. Later, the rocks around these indurated sediments are eroded and what was a channel now appears as a ridge. This enables geologists to use the inverted channels to map out ancient river deposits.

Map of the Aeolis Dorsa region with colors showing different topographic elevations. The red and brown are higher elevations and blue and green are lower. The brightly colored lines represent the different types of fluvial and alluvial features that were mapped, and the black boxes are smaller areas studied in detail.

Results: The locations and relative ages (which deposits are older than each other) of the inverted channels found in the Aeolis Dorsa region show two things. First, the deposits in the southern part of the region required more water and mud to form, implying that there was more rain and more cohesive (“sticky”) soil good for making mud in the south than in the north. Second, the amount of precipitation evolved over time. The older deposits were mainly fluvial and required more water/precipitation than the younger deposits which were mainly alluvial.

Why is this study important? This study is important because it shows how the climate varied over time and within different areas of the same local region on Mars. The study also used terrestrial analogs, which are places with similar features on Earth. This is important because we can’t yet go to places on Mars and directly sample the rocks, so scientists use these terrestrial analogs that they can directly sample to compare what they see in the geology of Mars.

The big picture: Understanding the local variations in paleoclimates on Mars is important to scientists because studying the past climate of Mars can tell us about past “habitability” – the availability of water and other resources for life. Studies like these can also help scientists find good places to land and explore further on future missions to Mars.

Citation: Jacobsen, R. E., and Burr, D. M., 2017, Dichotomies in the fluvial and alluvial fan deposits of the Aeolis Dorsa, Mars: Implications for weathered sediment and paleoclimate: Geosphere, v. 13, no. 6, doi:10.1130/GES01330.1

Attending Professional Conferences as an Undergraduate

Rose here –

Attending professional conferences can be a lot of fun. I have had the opportunity as a graduate student to attend several geology conferences around the country, but the first conference I attended was as an undergraduate senior geology major, and it set me on the course to pursuing graduate school.

Conferences for many professional organizations move around to different cities from year to year, making it easier for people in different regions to attend. During my senior year as an undergraduate, the annual meeting of the Geological Society of America (GSA) was held in Vancouver, British Columbia, Canada, just a few hours’ drive from my university, Central Washington University. Because of this, our department encouraged as many students to go as were able, since it was so close that we would not have to pay for plane tickets or other large travel expenses. There are several scholarships and travel grants available to students who are presenting research to attend professional conferences, but since I did not participate in a research project as an undergrad I was not able to receive this type of funding. To keep costs down, many of the students and professors from my department carpooled up to Vancouver and we crammed as many students as we could into a cheap hotel room a few blocks from the conference center.

Once we got to Vancouver and got settled in our hotel rooms, it was easy to see that this was the perfect place for a geology conference. It was my first time in Vancouver and I fell totally in love with the views. There were beautiful forested green mountains coming down right into the harbor. It was easy to imagine the subduction of the Farallon plate under the North American plate, forming the tall, (geologically) young mountains, followed by the giant glacial ice sheets covering the area during the last ice age and then retreating to leave behind such a beautiful landscape for us to enjoy.

During the conference, I was able to attend many interesting talks and poster presentations on a wide variety of geological topics, including paleontology, planetary geology, structural geology (earthquakes and tectonics), volcanology (volcanoes!), and metamorphic petrology (studying rocks that have been heated and transformed under high pressure without being totally melted). I was delighted to find that there were so many people studying so many interesting facets of geology, and was inspired to check out some ways to get involved in research myself.

There were many events happening during the week of GSA, some specifically aimed at students, and I attended as many of these as I could. Most were free or very affordable ($5-$15) for student attendees. There were a few networking events such as career lunches with professionals with jobs in industry (e.g., oil & gas), government, and academia. These lunches usually included a panel discussion or Q&A, followed by time to just mingle and talk to professionals and fellow students. Most GSA technical divisions (Structural Geology, Sedimentology, Planetary, etc.) had formal business meetings and social events (often combined) during the week of GSA. Some of these were free and some were ticketed, though if they charged they likely had a reduced rate for students. I found that these meetings were a good way to meet folks in fields of geology I thought I was interested in, and most of the people there loved to talk to students about what they do. One of my favorite events at GSA every time I’ve been is the Association for Women Geoscientists (AWG) networking breakfast. This is their annual business meeting, but also a way to get a good breakfast and meet other women geoscientists during the conference.

The exhibit and poster hall was one of the biggest rooms I had ever seen. There were hundreds of poster presentations of people’s work. This was a good way to spend time if I had an hour or two free. Walking around and looking at all the posters was a fun way to learn a lot about branches of geology that I knew very little about. There were also quite a lot of exhibitor booths for universities, geological equipment manufacturers, and various companies that hire geologists. Many of them were giving away free stuff (bookmarks, flash drives, pens), so it was fun to go around and see what I could get. I also loved walking around to all the booths for university geology programs and talking to students from other schools.

As a result of being exposed to all this cool science, I ended up applying to grad school for geology, and am now in the last semester of my Master’s degree! If you are an undergraduate (or even high school student) interested in science and you have the opportunity to attend a science conference in your area I highly recommend it.

Hosting, preparing, and presenting at a regional conference meeting

Audrey’s title slide before her presentation started!

The Geological Society of America has section meetings in addition to the large annual meeting. These are separated out by regions, so here in Tennessee, we are in the Southeastern section. Each year a different institution takes the lead on hosting, planning, and executing the meeting. This means that there is a ‘chair’ that oversees all others and has to get faculty and students to help run the meeting.

Some of the faculty in our department played roles in coordinating volunteers, field trips, exhibits, the presentations, sponsors, and finances. That’s a lot of different jobs and a lot of work! In order to get registration covered, many of the graduate students in the department volunteered to help run the event. This included tasks such as helping people with registration, or upload their talks, or being present in the session rooms in case something went wrong. All of these are rather simple tasks, but really vital for a well- functioning meeting. I helped with registration the night the meeting started and then again at 6:30 AM the next morning. I also don’t drive in town so I was biking in and out each day; needless to say I was exhausted by the end of the meeting.

Audrey Parker with some of her 3D printed foraminifera models!

In addition to volunteering at the event, I was helping three students prepare, and preparing a talk myself! Maggie and I have been co-advising Audrey, who has been working on developing lesson plans around digital models of microfossils! She gave a talk on these microfossils during SE GSA! This meant we prepared and practiced a talk for the two weeks before SE GSA happened. Practicing talks helps you remember what you want to say and get comfortable in a professional talk setting. There are often podiums so you can’t move freely and you can’t always move toward the screen so you have to get comfortable with a laser pointer!

Logan’s title slide!

Logan was also gave a talk during the meeting on her own research. I’ve been working with her on using two different methods to reconstruct internal anatomy of fossil echinoderms. One method involves cutting the specimen up into tiny pieces, and the other part of her research includes using fancy X-ray imaging to see the differences in mineral density within the specimen. The X-ray imaging does not destroy the specimens, which is a big perk. However, fossil echinoderms have calcite skeletons and the sediment that fills inside their bodies is the same mineral, so the density differences are quite minor. Logan and Audrey both picked times the two weeks before to practice in front of Maggie and I. Each time they improved and we provided them with feedback!

Logan presenting her research on evaluating model development of blastoid respiratory structures.

Chris was presenting a poster, so a little less stressful but he did have to field questions for about two hours. His work was on uncovering specimens that were less than 5 mm in height to aid in our understanding of blastoid growth! It’s really cool because there are two differently shaped blastoids from this same location and you can see the differences in shape all the way down to specimens smaller than ¼ mm. We practiced presenting his poster several times before the meeting. Once was on a big projector where he pointed out his work to us and then several more times once his poster was printed.

Chris Smith presenting his undergraduate research on blastoid ontogeny in the Thursday afternoon poster session.

Everyone did incredibly well presenting their work at SE GSA! Regional conferences are a really great starting conference for young scientists because there is typically less than 1,000 people in attendance. The larger annual GSA meetings include upwards of 8,000 people. That’s overwhelming! So, after I made sure the undergraduate students were feeling confident with their work, I was able to start my talk. I took a portion of my dissertation and went into more detail on specific aspects of the project and how it related back to Paleozoic echinoderms in general. I only had a few days to prepare my talk so I didn’t have much time to really practice or even write a script but it went well! Since I have more experience presenting, I made the right choice in focusing more on the undergraduates’ experience at SE GSA.

Rose Borden, Structural and Planetary Geologist

At Dry Falls, Washington, U.S.A.
My favorite part of being a scientist is discovering new things. I get to see things that no one has seen before and try to figure out how different pieces of evidence and types of information fit together to solve puzzles about how the universe works. My interest in science started when I was very young. I loved going on walks in my neighborhood and finding cool leaves and rocks and bugs. It’s super cool that now I get to study them as my job!

One of the wrinkle ridges I have mapped, with black arrows showing the location of the ridge. The colors are different elevations, with warm colors (orange and yellow) being higher and cool colors (green) being lower.
I am a structural geologist. This means I study how rocks move against each other, on the Earth and other planets. My current research project involves studying some features on Mars that were made by what is called compressive stress (rocks being pulled toward each other and pushed up to form a ridge shape). For this project I am looking at images sent back to Earth from spacecraft that orbit Mars. The data I use for my research are from cameras and other scientific instruments on spacecraft that orbit Mars. I have visual images (photographs) and topographic data (elevations of different features). I am trying to find all the ridges formed by compressive stress in a certain region near the equator of Mars called Aeolis Dorsa. When I find the features I am looking for, I measure how tall and long and wide they are to calculate how much the rocks have moved and in what direction.

My research helps us understand the different types of geologic processes that have happened on Mars in the past. Based on the many studies people have already done on Mars, we know that some of the process occurring on Mars include lots of rain causing rivers and lakes, giant volcanoes creating large lava plains, and wind storms depositing sand dunes and eroding rocks away to form ridges called yardangs. My research contributes to our knowledge of the tectonic processes that have occurred. This can help scientists decide what areas on Mars would be the best landing places for future rovers and manned missions and what kinds of scientific instruments or other equipment would be useful there.

Sarah Z. Gibson, Paleoichthyologist and Science Communicator

I am a paleoichthyologist, meaning that I am a paleontologist who specializes in fishes. In particular, my research is focused on the evolutionary history of early ray-finned fishes from freshwater deposits in North America; many of the fishes from these Triassic and Early Jurassic deposits remain undescribed and poorly understood with regard to their relationships to other fishes, as well as the roles they play in their respective environments. This time period is interesting to me because fish at this time were much different than what we see today. Much fish biodiversity had gone extinct at the end-Permian extinction event, and so lineages that persisted into the Mesozoic evolved into new habitats and niches. I focus on changes and trends in the morphology among several different groups of ray-finned fishes, and how these fishes evolved to exploit novel ecological niches at a turbulent time in Earth’s history.

I also serve as an editor for the PLOS Paleontology Community blog! While not directly related to my research, science communication is an avenue of my work as a scientist that allows me to branch out into other topics within the community and highlight new, exciting research that is available to everyone through Open Access! I enjoy getting to talk to other paleontologists about their research and projects, as well as help paleontologists and paleo enthusiasts access new information, resources, and useful tools.

This fish is Hemicalypterus weiri, a deep-bodied fish with unusual scraping teeth that may have been used to scrape algae or other attached organisms from a rocky substrate. Hemicalypterus is found in the Upper Triassic Chinle Formation of Utah, and is possibly the oldest representative of herbivory in fishes.

My research revolves directly around examination of anatomy and morphology of fishes from the orders Semionotiformes, Redfieldiiformes, Dapediiformes, and other closely-related ray-finned fishes. I collect most of my data through a microscope, examining specimens from museum collections or specimens that were collected in the field and prepared by great volunteers from the Utah Friends of Paleontology. I take high-resolution photographs of specimens so that I can examine and measure the morphological features of the fossils, and I also collect data from drawing specimens using a camera lucida. If you are unfamiliar with a camera lucida, it is a drawing tube microscope attachment that makes it possible to see a blank paper and my hand juxtaposed upon the specimen visible through the microscope oculars. I then trace the specimen I am seeing in the microscope onto the paper, which is actually placed next to the specimen though it looks like I am drawing directly on the specimen. The result is a drawing interpretation of the anatomy. This technique is old, but I still use it because it really forces me to closely examine and interpret what I am seeing. As my PhD advisor would say, “What you do not draw, you do not see.”

The data I collect may be written into a formal, detailed anatomical description, if the specimens represent a new species. That description can be used by other paleontologists to evaluate and compare to their own specimens. It also gets coded into a matrix of morphological characters, which includes other species that may or may not be closely related. I then analyze the completed matrix of morphological characters using phylogenetic software. The output is a hypothesis of evolutionary relationships of the group of fishes I am focusing on for the project, which I can then use to address evolutionary questions, such as the number of times a specific anatomical or morphological feature may have independently evolved, or assessing a role these fishes may have played in their respective ecosystems.

My research is part of a larger collaborative effort to assess the biodiversity of the Early Mesozoic of North America at a time in Earth’s history that saw major changes to the planet’s geography, several mass extinctions, and faunal turnover events that lead to the opening of novel ecological niches for both aquatic and terrestrial organisms. By looking at how species respond to catastrophic events, we may be more able to understand how modern biodiversity may evolve and adapt to modern changes that are being accelerated by human impacts.

My favorite part about being a scientist is realizing how vast and amazing this world and its history are! There is just so much to learn and see, and really, even with how far we have come as a society, there is still so much we don’t know! I love nerding out with fellow paleontologists, because frankly, how could you not love doing something this fun? It’s exciting! I also love discovering a new species, or uncovering a new specimen when doing fossil preparation. Just knowing that I am the first human to lay eyes on this little fish that died over 200 million years ago is very humbling.

My advice to young scientists would be to not get discouraged when you fail. I say when, not if, because failure is inevitable. Everyone fails, absolutely everyone. Every scientist you know has had grants rejected, papers revised, ideas spurned, etc. We all start somewhere! The key is persistence! Take the criticisms you will receive (and again, you will receive criticism at some point or another, so don’t despair!), and just use it to make your work better and more solid. Don’t forget that you are doing something totally awesome and worthwhile.

On a more practical note, practice reading and writing scientific papers. The scientific jargon can be a huge barrier to students and young scientists, but is so important when it comes time to share your own work with others. So read, read, read! Learn how to interpret their results. There is no excuse to not have access to scientific papers because Open Access research is ever-growing. Check out the weekly Fossil Friday Roundup (shameless plug!) which highlights new Open Access paleontology-related papers!

Follow Sarah’s blog here, for more information and updates on her research and check out the PLOS Paleo Community here, for awesome open access paleontology.

Applying to Graduate School

Maggie here-

I am finishing applying to grad schools for my Ph.D. and figured some of you might also be currently applying to graduate programs or starting to think about if you want to pursue a Master’s degree or a Ph.D. My main goals for this post are sort of two-fold: what is the process of applying to graduate programs and how do you stay sane while applying. So let’s get to it!

Key aspects of this post

  • Look for people and research that interests you, not just locations
  • Contact people at the school that you would want to work with-this is key! Look for people whose work interests you and start contacting them early-ask if they are taking students, what kind of research they do, what it would entail, etc.
  • Communicate with friends, professors, etc. if you need help with your statements or even just someone to say I know this sucks!
  • Make time for yourself-do things that aren’t related to applying to schools and have fun!
  • No matter how daunting and stressful this is, you are capable of doing this!

How to Apply for Grad School

Applying for grad school is very different from applying to undergraduate programs and unfortunately a lot less intuitive. When you were in high school (or shortly after) and applying to colleges there were a lot of people who were around to help you navigate applications and there may have only been one application you needed to fill out to send to many schools. You could also choose colleges based on what state or even which city you wanted to be in for the next four years.

Grad school is very different in that you are looking for specific research programs and people that you want to work with, rather than a location. The location can sometimes be a driver for your research, but in most cases that really is one of the last things that plays a role in your decision to apply there. Grad applications are also more short statement driven; you will be asked for statements of purpose (why do you want to come to this school), personal history statements, and the ever vague “additional statements.”

Statement of Purpose

This statement really is the meat of your application. What has made you decide to go to grad school, what do you want to study, why do you think this school and this advisor is the only place that you can learn what you want to learn. This statement can be totally daunting because often there are no directions or clarifying statements about what to include. I personally like to include a quick paragraph that is more of a narrative- what experience in science did I have that has stuck with me and made me want to be a scientist as an adult? Did you go to a cool summer camp or have an awesome science teacher? Something to show your background and make you a human can make your statement easier for you to write and easier for people to read. After that paragraph is your chance to wow them- what super cool research have you done, do you have a research question that you just have to know the answer to? How does this advisor and school help you reach your research and personal goals? This statement really is up to you to decide which direction you take it in, just make sure that if a school does want you to address something specific in this statement that you answer it!

Personal History Statement

The personal history statement is a place for you to go a little more in depth with personal experiences that you have had (positive or negative) that have led you to where you are today. It can be family or personal matters, or even research experiences that you feel have shaped your career trajectory. In this statement you can also address any “problems” in your transcripts or academic records. If you do choose to address something that was a challenge to you or something that impacted you negatively, try to keep positive language throughout. How did you overcome these challenges, what did you learn about yourself with this challenge, etc. Grad schools and advisors want to know who you are now, not who you were your first semester freshman year. If you have something in your transcript that you want to address and a personal history statement isn’t asked for, I have also asked a trusted letter writer to discuss that in my letter. The personal history statement is a chance for you to show how much you shine, even in the face of adverse conditions.

Other Documents

This upload button can cause a lot of grief because it will literally say “other documents.” Don’t panic, this is not required and you don’t have to upload something if you don’t have something else you want to add. If you know you want to be a professor and you have already had some teaching experience so you have a teaching philosophy or want to learn how to teach more effectively, that could be a statement you might add. If you love doing outreach and you feel very strongly that you can bring something to the table with your outreach efforts, you can add a statement about that. I just submitted my first “other document” with my Ph.D. applications and I only submitted it because I feel very strongly about the importance of teaching and outreach and wanted to share that side of myself with the schools I was applying to. If you don’t feel like you need to share anything else with the schools, don’t. It’s not something to stress too much over, because this whole process is stressful enough!

How to stay sane while applying

As someone who is currently applying for grad schools, this is 100% the hardest part for me. Even though I have really supportive family and lab mates who read over every statement that I write, the process can still feel very overwhelming. You have worked so hard for so long and you just want these people you have talked to to see how great you are and be deemed worthy enough to work with them. The best advice I can offer is to surround yourself with friends. Some of them may have done this before or are in the process of doing this with you, take the time you need to talk about applications but don’t let it consume your life. Spend time with people away from computers, go do fun things, remind yourself that life isn’t just about school. Take walks during the day-I spend ~8 hours a day sitting at my desk and a lab bench and I have found that taking a walk with my friends during the day can be just what I need to feel refreshed and ready to keep working. Play with animals-my cat has been a very big help in this application process because he provides so much comic relief! Play music that boosts you up and makes you feel good-this past week my lab group had a jam session to the Moana soundtrack. If that isn’t love and support, I don’t know what is!

Intergovernmental Panel on Climate Change (IPCC) I: Current Climate-Driven Impacts

Andy here –

Teaching about climate change this year took a toll on me. I’m normally a resilient and fairly hopeful person, but diving into the current and future impacts of climate change commonly leaves a person shell-shocked. How do climate scientists cope with existential dread?

Scientists are people too. Some of us are young, many of us have kids. It is difficult to stare this problem in the face day in and day out, without feeling like you are watching a slow motion train wreck, with your elected officials stepping on the gas rather than using the brakes. I’ve decided that I’m going to share those feelings with other people. We’re starting with the current impacts. A second post will follow with the basics of climate modeling, and finishing with what we think will happen next.

What follows here is a small, incomplete collection of current climate-driven impacts and assorted links to other information. I’ve tried to keep it to just impacts that are established in the Intergovernmental Panel on Climate Change (IPCC). These are things that science can firmly establish as happening right now due to climate change.

Hydrological (Water) Cycle

Data showing percent of days per year with much below normal rainfall amounts (brown bars) and much above normal rainfall (green bars) within the continuous U.S. Notice that as you move from 1910 to 2010, the length of the brown bars decreases, while the length of the green bars increases. This indicates that there has been increasingly more days with rainfall. Data from NOAA U.S. Climate Extremes Index (CIE).

We can currently say there are substantial changes to where and how rain and snow fall because of climate change. These changes have altered our ability to use water, both in quantity and quality. If we look at Michigan as an example, it has an increase in yearly precipitation of 2/3 of an inch per decade since 1960. Massachusetts has seen >1 inch per decade (data here). Other states are not as lucky, and are currently seeing a decrease (e.g., California). Our freshwater is increasingly contaminated due to both low (drought) and high (flood) conditions in many locations in the US. 10% of counties are currently under high or extreme risk of a water shortage.

We, as humans, are at the start of these changes as well.

If you’re curious what the US government has to say about water use changes, click here for the National Climate Assessment Water Use (from 2014) page. It also has very scary maps!

IPCC: In many regions, changing precipitation or melting snow and ice are altering hydrological systems, affecting water resources in terms of quantity and quality (medium confidence).

Click here to explore the National Climate Assessment site’s findings from 2014 on water supplies.


We can also say that animals, plants, and other organisms have had responses to climate change. Coral reefs are the easy and moderately better-known connection, what with nearly 50% of the Great Barrier Reef corals dead in the northern section. Polar bears are similarly simple. With the arctic warming faster than the globe, 3/19 tracked polar bear populations are shrinking, while we don’t have enough data to say anything about the other 9/19. At least one of the ‘stable’ populations has shrunk since 25 years ago (stability is a ~12 year average). More warm winters mean more ticks in moose territory. A warmer West coast means stressed salmon. And so on.

While a projection (estimation based on current data), which I’m trying to save until later, click here for a map visualizing how species will need to move to maintain their proper habitat in a climate-shifting world.

IPCC: Many terrestrial, freshwater, and marine species have shifted their geographic ranges, seasonal activities, migration patterns, abundances, and species interactions in response to ongoing climate change (high confidence).


Climate change also has a negative effect on crop growth. Unlike what Lamar Smith has written (R-TX, head of the House Committee on Science, Space, and Technology), we do not expect there to be a benefit of increased CO2 in plant growth. Temperature effects far outweigh the small growth boost of higher CO2, and will lead to decreased seed yields. Climate change will shift where things grow; in some areas of India that used to get more snow there are new potato crops growing now with the milder winters. That’s good, but it’s quite the outlier. Wheat, rice, maize, soybean, barley and sorghum all respond negatively in rising temperature. Wheat production has already dropped 5.5%, and Maize by 3.8%. That is with our limited (in the face of what is projected) temperature changes so far.

Click here for an article by Scott Johnson that goes into more detail.

IPCC: Based on many studies covering a wide range of regions and crops, negative impacts of climate change on crop yields have been more common than positive impacts (high confidence).

Graph of projected increases (cool colors) and decreases (warm colors) of crop yields in the coming decades under increased warming. Notice how decreasing crop yields are more prevalent from 2010-2029 to 2090-2109. Image from IPCC (2014).

Extreme Weather Events

A) Percent of summer days when maximum temperatures exceeded long-term daily 95th percentile (the hottest recorded temperatures) from 1880 to 2005 over Western Europe. B) Heat wave intensity (number of days heat waves lasted) in Western Europe. Data from the Norwegian Meteorological Institute, 2013.

Climate change also increases the chances of having extreme weather events. Importantly, we can’t say that an individual hurricane is directly a result of climate change. We can say, however, that they are more likely. We can say that they’re made stronger, when they do happen. Harvey and others aren’t because of climate change but they’re more likely to happen and be worse because of it. Storms like Harvey, or Maria, or Irma, or Ophelia (which even hit the UK!) are more likely, and therefore more frequent, because of our warmer world.

Wildfires (click here for more details) are also made more common, due to drier conditions in some areas. So are floods, where there’s an increase in precipitation. And heatwaves. And on, and on.

This will obviously stress our systems to care for those affected. Given this summer and fall, I shouldn’t really need to back up that claim with supporting data.

IPCC: Impacts from recent climate-related extremes, such as heat waves, droughts, floods, cyclones, and wildfires, reveal significant vulnerability and exposure of some ecosystems and many human systems to current climate variability (very high confidence).

Economic Impacts

Climate change has cost us money, and it will likely continue to cost us. We can say this with a high degree of certainty. Wildfires, floods, storms, droughts, earthquakes, tsunamis, all have a monetary cost. The insurance industry is well aware of the increasing trend in the costs, and so keeps track. We can divide the cost of these natural disasters into things that will be altered by climate change (wildfires, floods, storms, droughts, so on) and those not affected by climate change (earthquakes, tsunamis, etc.). This acts as a nice check against our buildings being more expensive, disaster relief being more expensive, or something like that. When we do this, all of the climate-related costs are increasing dramatically (click here for more details), while those not affected by climate change are only increasingly slightly. The number of climate-related (or extreme-weather) disasters is increasing, while the number of earthquakes is flat.

IPCC: Direct and insured losses from weather-related disasters have increased substantially in recent decades, both globally and regionally.

Ocean Temperature Changes

Top: Observed global annual averaged land and ocean surface temperature anomalies. Bottom: Same data as above, but decadal averages. Grey boxes represent uncertainty. Image from IPCC (2014).

Many of the ocean acidification impacts are similar or work alongside the impacts of increases in ocean temperature (click here for more details). Two examples: Corals bleach primarily due to temperature and their ‘skeletons’ fall apart in response to the pH. Similarly, when temperature rises, krill reproduce in smaller numbers. Krill are a key part of the food chain for things that people find cute, like penguins, seals, and many whales. Together, if those larger animals are stressed or starve, their predators die too.

Warmer water also expands, so a warmer ocean means that sea-level rise occurs more as well. This can magnify the storm surges, amplifies the effect of the melting glacial waters, and is generally a very bad thing.

Oh yeah, and the rate that the ocean is warming is accelerating.

Ocean Acidification

Many things have changed in the oceans due to the increase in carbon dioxide in the atmosphere. The first is that the ocean has absorbed quite a bit of that carbon dioxide. The pH has changed by 0.1 units since the industrial revolution. pH scales are not linear, so this actually is a 30% increase in acidity.

Marine life obviously feels this massive change. Because they are smaller and more fragile, larval stages of various organisms or plankton feel the effects first. While there are other things at issue (though research is working on detangling the others: water quality issues, low oxygen, or changes in diseases, etc.), the current rash of losses in the oyster industry are at least partially due to changes in acidity. The oyster industry is a $100-million-a-year industry. Click here for more details.

Corals, too, are stressed. Coral bleaching is due to temperature, but the material that corals make their skeletons out of is susceptible to acidification. It makes it harder for them to reproduce, grow, and live. They also dissolve and erode faster under higher amounts of acid.

There are currently more than a million other species living in coral reefs, making reefs some of the greatest spots of diversity on Earth.

Sea Level Rise

Top: Average sea ice extent in millions of km squared for the Arctic and Antarctica from 1900 to 2010. The Arctic is melting at an alarming rate. Bottom: Global average sea level rise in meters from 1900 to 2010. Image from IPCC (2014).

Sea level has risen between 10-25 centimeters. Because much of the coast is really flat, that means much more area has been lost than it appears. We think that the loss to property values is between $3-5 billion a year. In structural loss, it is $500 million. We spend a lot of money to keep the coast where it is too; like the $14 billion Louisiana is expecting to put into coastal barriers along the Mississippi River delta. In other areas, the coast just erodes and land disappears into the ocean. Click here for more details.

Click here for a neat NOAA page that lets you see what happens as sea level rises.

We know sea level rise also has a cost on communities and lives. An entire community, Shishmaref in Alaska, has lost 2,500 to 3,000 feet of land in 35 years. Other communities, Kivalina, Newtok, Shaktoolik, and others (31 in total) need to be moved according to the Army Corps of Engineers. At least one community has voted to move to the mainland, but without funding to move, cannot.

Marginalized Communities

Climate change is a volume knob for social justice issues. That volume knob is sensitive.

Communities that are marginalized (have less political power, less money, etc.) are far more at risk in a changing world. If you have less power in society, odds are that a society under stress from climate change will be less likely to support you in the face of needs (even a lesser need) of a more powerful,other group.

This is referred to as ‘Climate Justice’. The People’s Climate March in Washington, D.C. (2017) was a wonderful example of how this has been embraced. From what I could tell, there were far more people there interested in social justice (indigenous communities, religious communities, etc.) than the scientists or folks who allied themselves with science at the march. It’s called the People’s Climate March for a reason. Click here for the NAACP’s page on Climate and Environmental Justice.

There is no clearer example than what happened and is currently happening in the US in 2017. Puerto Rico is not a state. Florida and Texas are. The US response to Puerto Rico which, again, is a part of the United States of America is the textbook example of this. Puerto Rico does not have representation in the federal government, so is ‘less important’ from a hardline (and inhumane) political point of view. The differing response from the federal government is a direct and obvious example of this IPCC finding.

Click here for more details on climate justice.

IPCC: Differences in vulnerability and exposure arise from non-climatic factors and from multidimensional inequalities often produced by uneven development processes (very high confidence). These differences shape differential risks from climate change.


Climate change is currently changing the water cycle, changing how water resources can be accessed. We’ve seen that animals and plants are already shifting their habitats due to climate change. A specific, but very human-centric part of that is how crops are and will respond. Harvests, in bulk, are down for many of our grains. Climate change has already cost us lots of money, and will continue to.

Lastly, but probably most importantly, climate change is currently felt by disadvantaged peoples disproportionately. The US response to Puerto Rico which is a part of the US is the textbook example of this. Puerto Rico does not have statehood, so is ‘less important’ from a hardline (and inhumane) political point of view.

We cannot, scientifically, say that Maria and Harvey and Irma and Ophelia are because of climate change. Attribution is difficult due to the statistics involved. We can however say that the scientific prediction for what happens in a warmer world is larger, more damaging and frequent storms. That is what we experienced in 2017.


IPCC, 2014. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II, and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (Core Writing Team, R.K. Pachauri and L.A. Meyer, eds.). IPCC, Geneva, Switzerland, 151 pp.

‘Extreme Climate Events in Europe: preparing for climate change adaptation”, 2013. Norwegian Meteorlogical Institute, Oslow, Norway, 140 pp. 

Darwin Day Celebrations 2018

Maggie here –

The Darwin Day events at the University of Tennessee, Knoxville have been running since 1997 and I was one of the leaders for the 2018 events. Darwin Day is all about celebrating the life and work of Charles Darwin, and sharing that information with members of the UT campus as well as the surrounding community in Knoxville. For this year’s celebration we hosted a birthday party in collaboration with a McClung Museum Family Fun Day and had a special keynote lecture by Dr. Nizar Ibrahim.

Darwin and Wallace puppets that are used to advertise our Darwin Day events. These puppets are ~10 feet tall and our very wonderful friends wear them and walk around or even dance in them!

The birthday party had cake (of course!), games, crafts, a scavenger hunt, and a larger-than-life puppet of Charles Darwin. This year, we wanted to make sure that our activities were designed to be able to really teach about evolution. One of the activities was to test out different “finch beaks” to see how easy it was to pick up “food”. Our finch beaks consisted of paper clips, binder clips, and wooden skewers that were used to pick up different objects. For our younger guests this activity concluded with a quick talk about which beak they thought was easier to use and how that might translate to real beaks on birds. For our older guests we were able to bring in the ideas of adaptations, natural selection, and speciation during the wrap up conversation. We were also lucky enough to have one of the McClung Museum docents come in for the birthday party to lead a couple of tours through the Human Origins exhibit. This was the first time that these tours had been led during Darwin’s Birthday party and helped us engage in evolution discussions with our older guests. As with any large scale event, each year is a little different and we continually try to come up with new activities and try to reach new areas of the Knoxville community. While this birthday party was incredibly successful (we had ~260 people come!) we are already looking forward to next year and making the birthday party even more successful!

Leslie Chang Jantz, Curator of Education; Callie Bennet, Asst. Museum Educator; Emily Nield, Earth and Planetary Sciences graduate student all work to pass out cake and snacks to birthday party guests.

The evening lecture with Dr. Ibrahim was a rewarding excursion through the past. He has done significant work reconstructing the ecosystems of the Cretaceous of Morocco. He has primarily worked on uncovering an ancient river system community that was dominated by many types of predatory animals, namely Spinosaurus. There was a special underlying story on a German paleontologist, Ernst Stromer, who originally discovered Spinosaurus, but the specimens were lost during World War II in the bombing of Munich. Dr. Ibrahim was able to find another specimen of Spinosaurus in Morocco -his “needle in the Sahara”. He worked with local fossil hunters as well as a museum in Italy and was able to find more bones that belonged to Spinosaurus. There is not yet a complete skeleton of Spinosaurus.  However, with new technology researchers were able to 3D print the skeleton of Spinosaurus that tours museums today. Dr. Ibrahim’s talk impressed upon the audience that paleontology is hard work, but that collaboration with other scientists and foundations can ease that burden and make discoveries that much more rewarding. He also gave great insight on the challenges that come with doing field work in the Sahara desert and how terrifying it can be when two of your three vehicles break down in the middle of the desert! I think I’ll stick to local field work and museums…

Artists rendition of Spinosaurus in the Cretaceous river system of Morocco. Painting by Davide Bonadonna.

Putting on a large scale event like Darwin Day during the last year of my Master’s degree was very challenging-I often felt that if my days weren’t planned well or if I wasn’t working a month ahead of schedule that I wouldn’t be able to pull off writing my thesis and planning a birthday party and speaker visit! It was incredibly difficult, but doing outreach events like this are what makes science rewarding in my eyes. I have spent several years cultivating my scientific knowledge, but my passion (outside of research!) is doing outreach and talking to the communities that I work and live in about science and sharing my excitement about research with them. Darwin Day at UT changes and morphs every year based on who is leading it, but it continues to grow and continues to reach more people as the focus becomes more centered on reaching the communities surrounding the university. I also have to thank Jen Bauer, Joy Buongiorno, and Audrey Martin, as well as all of the other volunteers, for their help and support with executing this year’s Darwin Day events-these events could not have happened without the help of other amazing scientists who want to share science with the public!

Click here for an interview that discussses the Darwin Day program at UT.

Ranjeev Epa, Invertebrate Paleontologist

Fig. 1: End to an intense day of fossil collecting

I am an invertebrate paleontologist. My research interests are mainly focused on paleoecological themes, especially investigating biotic interactions (predator-prey relationships, paleoparasitism) and exploring how variations in body morphology (the form of living things) can be used as a proxy to interpret paleoenvironmental attributes. As an example, in snails, shell shapes and ornamentation (ex. spines or other shell modifications) can be influenced by predators (biotic) and/or by abiotic factors, like flow rate or nature of the substrate (the sediment or rock on which the animal lives).

I work primarily on marine invertebrates. My favorites include gastropods (snails), bivalves (clams), elephant tusk snails (which are very cool), sea urchins, and foraminfera. I started my journey in my home country, Sri Lanka, where I worked on Miocene marine fossils of Aruwakkalu in Sri Lanka (Epa et al., 2011). After joining Ohio University for my masters, I studied the late Oligocene freshwater ampullariid snails of Tanzania (Epa et al., 2017 in press). Currently, I am investigating predatory and parasitic interactions within a collection of Plio-Pleistocene marine bivalves from Florida. Here, I look at predatory drill holes (Fig.2C) and trematode (a group of flatworms) parasitic traces (blisters and pits; see Fig.2A and B) to explore taxonomic selectivities (specific animals getting harmed) and to investigate potential relationships between environmental factors and variability in intensity of such biotic interactions.

Fig 2. A – B: Potential traces of trematode parasitism. A. Pits. B. Blisters.
C. Oichnus paraboloides Bromley, 1981, predatory drill hole produced by a naticid gastropod

Bivalves (clams) are not only pretty (Fig.3) but also one of the key contributors in maintaining good ecosystem health, thus acting as keystone species at local geographic scales. In addition, throughout human history, bivalves (mollusks  in general) have been an important component in the food industry and many communities around the world have direct interactions/dependence on their regional mollusc communities (malacofauna).  Thus, community structure and population dynamics of bivalves affect ecosystem health, human health and, to a large extent, economies of coastal communities.

One of the research questions I address in my doctoral research is the effects and factors governing trematode parasitism among bivalves. Parasitism is known to cause detrimental effects on bivalves. However, little work has been done on paleoparasitology compared with other biotic interactions like predation. So, my research will look in to the geological and modern records/trends of trematode parasitism in bivalves to explore factors that influence variation in parasitism. Using these data, I plan to interpret how climate change can influence parasitism among bivalves and add a novel dimension to stress the importance of reducing our footprint on Earth.

Fig 3. Pectens collected from Sri Lanka

There is so much I love about what I am doing. Getting to work with my favorite animals makes me feel that I have the best job in the world. As a scientist, you have the power to communicate important scientific findings to people with different academic backgrounds and to people that hold different societal positions. This is especially important as at present, as our carbon footprint on the blue planet is a serious cause for concern. My advice to young scientists is simple: love what you do and do what you love. ALWAYS try to maintain a balance in life.

Follow Ranjeev’s research profile by clicking here and keep up with his updates on Twitter here.

New echinoderm fossils from Anticosti Island, Quebec

Late Ordovician (Hirnantian) diploporitan fauna of Anticosti Island, Quebec, Canada: implications for evolutionary and biogeographic patterns

Sarah L. Sheffield, William I. Ausich, Colin D. Sumrall

What data [were] used? New fossils found from Anticosti Island in Quebec, Canada.

Methods: New fossils of poorly understood echinoderm (relatives of sea stars) fossils discovered from Upper Ordovician (445-443 million years ago) rocks were analyzed and compared with middle Silurian (434-428 million years ago) to better understand biogeographic and evolutionary trends.

Results: The Holocystites Fauna is a group of poorly-understood diploporitan echinoderms (a term that just means they breathe out of sets of double pores found on their body) that scientists assumed to have only lived in the midcontinent of the United States (e.g., Tennessee, Iowa, Indiana, etc.) during a very specific time within the Silurian. New fossil species Holocystites salmoensis, however, tells us that they actually also lived during the Late Ordovician of Canada, which extends their known range nearly 10-15 million years!

This fossil of Holocystites salmoensis represents a very important new datapoint that helps scientists understand poorly known echinoderm transitions from the Late Ordovician to the Silurian. A. The mouth area of Holocystites salmoensis. B. a close up of the diplopore respiratory structures. C. A line drawing of the mouth area of Holocystites salmoensis. D-E. Other fossils of Holocystites salmoensis and (F) an unidentified diploporitan found in the same deposit (Sheffield et al., 2017).

Why is this study important? So at first glance, this paper might not seem so important-it’s just one new fossil of a relatively rare group of echinoderms. What is so important about this is the time in which these fossils were found. Rocks from the Upper Ordovician, during which this fossil was found, are very rare because the ocean levels were very low. Earth was in an ice age, so a lot of ocean water was taken up in glacial ice. When sea levels are low, fewer rocks are preserved; therefore, fossil data from low sea levels are rare. Evolutionary transitions of fossils from the Ordovician through the Silurian aren’t well understood. Now that we’ve found evidence of Ordovician Holocystites, we can infer a lot more about when and how these organisms evolved.

The big picture: Crucial information about how life on Earth evolved is often hard to find from times like the Late Ordovician. Actively searching for rocks during these times and identiying fossils from within them can tell us a lot about how past life responded to mass climate change (like ice ages and significant warming periods). It can also tell us a lot about how organisms expanded and shrunk their biogeographic range. Even one new fossil, like the one identified in this paper, can change a lot about what we think we knew!

Citation: Sheffield, S.L., Ausich, W.I., Sumrall, C.D., 2017. Late Ordovician (Hirnantian) diploporitan fauna of Anticosti Island, Quebec, Canada: implications for evolutionary and biogeographic patterns: Journal of Canadian Earth Sciences, v. 55, p. 1-7, doi: 10.1139/cjes-2017-0160