Science & Technology

Thomas: Carbon Impact—Not Volcanism—Key in Driving the Cretaceous Mass Extinction

Thomas

Ellen Thomas

(By Kayleigh Schweiker ’22)

As scientific study regarding the mass extinction of marine life during the Cretaceous era has progressed, theories including extraterrestrial impact and intense volcanism have surfaced. However, a recent study co-authored by Ellen Thomas, Harold T. Stearns Professor of Integrative Sciences, suggests that carbon impact—not volcanism—was key in driving the Cretaceous mass extinction.

In a paper titled “Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact,” which was published in the Oct. 21 issue of the Proceedings of the National Academy of Sciences (PNAS), Thomas and her colleagues discuss how increases in ocean acidity played a driving force in the mass extinction of marine organisms. This mass extinction, labeled the “Crustaceous-Palogene die-off,” or the K-Pg event, led approximately 75% of plant and animal life on Earth to extinction. Though scientists have suggested that the presence of sulphuric acid proceeding the crash may have caused ocean pH levels to drop, Thomas and her team’s research on this topic reveals a different possibility.

NASA Funds Study of Gilmore’s Venus Mission Concept

Martha Gilmore

Martha Gilmore, the George I. Seney Professor of Geology, professor of earth and environmental sciences, believes we have a lot to learn from studying Venus—yet the United States has not sent a mission to the Earth-sized planet since the early 1990s. That’s why Gilmore has proposed a major flagship mission concept study to assess whether Venus was ever a habitable planet by looking at its rocks and atmosphere.

In October, NASA agreed to fund the planetary mission concept on Venus submitted by Gilmore, a planetary geologist, and colleagues at several other institutions, who come from varied disciplines. Gilmore, who is the principal investigator, said NASA received 54 proposals and selected 10 to feed into the next Planetary Decadal Survey. Theirs was the only proposal on Venus to receive funding.

In 2020, the National Academy of Science will convene a panel of scientists and engineers to determine the scientific priorities for Planetary Science over the period 2023–2032. This Planetary Decadal Survey is conducted every 10 years and is tasked with recommending a portfolio of missions to NASA. The mission concepts that were funded will be developed for consideration by the Decadal Survey. In the coming months, Gilmore will be meeting and communicating regularly with her science team and conducting mission design runs at NASA’s Goddard Space Flight Center in Maryland. Final reports are due to the Decadal Survey in June 2020, and will describe mission architecture, cost, and how the mission will address the scientific priorities of the Decadal Survey and NASA.

Gilmore’s expertise is on the surface morphology and composition of Venus, Mars, and Earth, and her PhD focused on Venus during the United States’ Magellan mission. She explained that all three planets are rocky, and there is evidence that they all had oceans early in solar system history. Scientists believe that Mars’s ocean dried up first—within about one billion years—and that Venus’s ocean may have lasted for two or three billion years.

“Thus, for most of solar system history, there were two Earth-sized planets with oceans,” said Gilmore. “Was Venus habitable like the Earth and if so, what changed?”

Paper on Bacteria Adhesion Named “Editor’s Pick” by Journal of Biological Chemistry

Rich Olson

Rich Olson

Katherine Kaus PhD '18

Katherine Kaus

A paper written by Associate Professor of Molecular Biology and Biochemistry Rich Olson and his former students was designated as an “Editor’s Pick” by the Journal of Biological Chemistry. Only 2% of the approximately 6,600 papers published each year in the journal receive this designation.

Titled “The 1.9 Å crystal structure of the extracellular matrix protein Bap1 from Vibrio cholerae provides insights into bacterial biofilm adhesion,” the paper, published on Oct. 4, explores how bacteria “glues” itself to surfaces in the environment. The co-authors include Alison Biester ’19, Ethan Chupp ’18, Jianyi Lu ’17, Charlie Visudharomn ’17 and Katherine Kaus PhD ’18. Kaus, who is first author on the paper, is featured in a special profile on the JBC website.

Bacteria commonly form structures called biofilms, which are communities of living cells encapsulated by a three-dimensional matrix of secreted proteins, nucleic acids, and carbohydrates. Biofilms are a defense mechanism against environmental challenges and play a role in many pathogenic diseases.

Wesleyan in the News

NewsIn this recurring feature in The Wesleyan Connection, we highlight some of the latest news stories about Wesleyan and our alumni.

Wesleyan in the News

1. The Nation: “Edward Snowden Deserves to Be Tried by a Jury of His Peers, Just Like Everyone Else”

In this op-ed, Associate Professor of Government Sonali Chakravarti argues against the Justice Department’s decision to deny Edward Snowden’s request for a jury trial. She contends that in Snowden’s case, in which he is accused of leaking classified information from the National Security Administration in 2013, a jury trial “is not only a viable alternative to a hearing before a judge; rather, given the nature of the charges—where the defendant has supposedly acted to protect the people from the very state that would charge him with a crime—jury deliberation is the proper forum for discussion of appropriate punishment and is the bulwark against the potential misconduct of the state.”

2. Transitions Online: “Stuck in the Middle”

Peter Rutland, the Colin and Nancy Campbell Professor in Global Issues and Democratic Thought, professor of government, and Dmytro Babachanakh ’20 explore the history of U.S. involvement in Ukraine, and call upon U.S. leaders of both parties to stop “treating lesser powers as political instruments.”

3. Tulsa World: “Save the Little Grouse on the Prairie”

Alex Harold ’20 is the author of this op-ed that calls for the lesser prairie chicken to be placed on the endangered species list to get the protections it desperately needs, as over 90 percent of its habitat has been degraded or destroyed. While many haven’t heard of this bird, Harold explains that it is an “indicator species” that “reflect(s) the health of the entire prairie ecosystem.” Harold wrote the op-ed as an assignment in E&ES 399, Calderwood Seminar in Environmental Science Journalism, taught by Professor of Earth and Environmental Sciences Suzanne O’Connell, this semester. The Calderwood Seminars are offered in a variety of disciplines to teach students how to effectively communicate academic knowledge to the public. Read more here.

Genomics Analysis Students Collaborate on Second Published Article

This fall, Assistant Professor of Biology Joe Coolon is teaching Principles of Biology (MB&B181) and Cell and Development Journal Club (BIOL505).

Assistant Professor of Biology Joe Coolon and 26 Wesleyan students are coauthors of a recent paper published in G3.

The second publication by students in Genomics Analysis (BIOL 310) has been accepted by the well-known journal G3: Genes, Genomes, Genetics. This adds 26 Wesleyan students to the ranks of more than 40 students who have become published authors through the course’s research on Drosophila sechellia, a type of fruit fly evolved to eat a plant that is toxic to most insects.

The recent paper, “Genomics Analysis of L-DOPA Exposure in Drosophila sechellia,” is coauthored by all 20 students in Assistant Professor of Biology Joseph Coolon’s class, and six students in his lab.

“I created my Genomics Analysis course as a way to provide more students with a course-based research experience where students participate in scientific discovery and the generation of new knowledge, and don’t just consume knowledge generated by others,” said Coolon. “This means each year the students taking the course learn material generated and published by the previous iterations of the course.”

O’Connell in The Conversation: How Deep is the Ocean?

Wesleyan faculty frequently publish articles based on their scholarship in The Conversation US, a nonprofit news organization with the tagline “Academic rigor, journalistic flair.” Professor of Earth and Environmental Sciences Suzanne O’Connell has written a new article for The Conversation’s “Curious Kids” series answering the question “How deep is the ocean?” The article is based on her research studying the sea floor.

Curious Kids: How deep is the ocean?

The remotely operated vehicle Deep Discoverer captures images of a newly discovered hydrothermal vent field in the western Pacific. NOAA

The remotely operated vehicle Deep Discoverer captures images of a newly discovered hydrothermal vent field in the western Pacific. (NOAA)

Explorers started making navigation charts showing how wide the ocean was more than 500 years ago. But it’s much harder to calculate how deep it is.

If you wanted to measure the depth of a pool or lake, you could tie a weight to a string, lower it to the bottom, then pull it up and measure the wet part of the string. In the ocean you would need a rope thousands of feet long.

In 1872 the HMS Challenger, a British Navy ship, set sail to learn about the ocean, including its depth. It carried 181 miles (291 kilometers) of rope.

During their four-year voyage, the Challenger crew collected samples of rocks, mud and animals from many different areas of the ocean. They also found one of the deepest zones, in the western Pacific, the Mariana Trench, which stretches for 1,580 miles (2,540 kilometers).

Molecular Biophysics Program Hosts 20th Annual Retreat

MBB

Three Wesleyan faculty, one guest, and one alumnus delivered talks during the 20th Annual Molecular Biophysics Retreat on Sept. 26. The speakers included David Beveridge, Joshua Boger University Professor of the Sciences and Mathematics, Emeritus; Lila Gierasch, Distinguished Professor of Biochemistry and Molecular Biology and Chemistry at the University of Massachusetts, Amherst; Erika Taylor, associate professor of chemistry; Michael LeVine ’11 of D.E. Shaw Research; and Laverne Melón, assistant professor of biology.

On Sept. 26, the Molecular Biophysics Program hosted its 20th Annual Molecular Biophysics Retreat at Wadsworth Mansion in Middletown. Several Wesleyan faculty, students, and guests attended the all-day event, which included five talks, two poster sessions, and a reception.

Lila Gierasch, Distinguished Professor of Biochemistry and Molecular Biology and Chemistry at the University of Massachusetts, Amherst, delivered the keynote address, titled “Hsp70s: Allosteric Machines that Perform a Multitude of Cellular Functions.” Gierasch, a leader in the field of protein folding, is a newly elected member of the National Academy of Sciences. Her work focuses particularly on folding in the cell and understanding the action of folding helper proteins, known as chaperones. Her career-long contributions were recently recognized by the American Peptide Society with a lifetime achievement honor, the Merrifield Award. She is also a recipient of the American Chemical Society’s Ralph F. Hirschmann Award in Peptide Chemistry, an elected member of the American Academy of Arts and Sciences, and is currently editor-in-chief of the premier biochemical publication, the Journal of Biological Chemistry.

Sultan to Lead $2M Evolutionary-Developmental Biology Project

Sonia Sultan

In the Wesleyan Research Greenhouse, Professor of Biology Sonia Sultan studies how Polygonum plants develop and function differently in response to contrasting environmental conditions. (Photos by Olivia Drake)

With support from a $2 million John Templeton Foundation National Sciences grant, Professor of Biology Sonia Sultan will spearhead a multi-institution evolutionary biology research project over the next three years.

The project, titled “Agency in Living Systems: How Organisms Actively Generate Adaptation, Resilience and Innovation at Multiple Levels of Organization,” developed from Sultan’s research on how individual organisms respond to their environments. Sultan and her Wesleyan research group study this question through experiments with the common plant Polygonum.

Sultan's data on Polygonum plant have broader implications for understanding evolution.

Sultan’s data on Polygonum plant have broader implications for understanding evolution.

Sultan’s previous findings have shown that genetically identical Polygonum plants can develop very differently depending on their growth conditions, allowing adaptive adjustments by individual plants without any genetic change. Because these adjustments are made actively by plants, rather than pre-scripted by their DNA sequence, this insight poses challenges to prevailing conceptual models for development and evolutionary adaptation.

“Scientists are particularly keen to understand these types of induced changes because they may help populations to very rapidly adapt to novel environmental stresses caused by human activities,” Sultan said.

The Templeton Foundation grant supports a consortium to investigate more broadly this property of biological agency—the ways in which active, real-time responses by living organisms influence the organisms’ own features. Sultan and her international team of co-investigators will focus on the active response mechanisms produced by evolution that grant organisms a degree of agency in shaping their own development, behavior, and subsequent evolution.

“New findings over the past decade about gene expression, development, the nature of inheritance, and the basis of adaptation, have led developmental and evolutionary biologists to re-examine some fundamental and long-standing ideas,” Sultan said. “The concept of agency may provide a unifying framework at a time when many scientists are seeking to update and expand those ideas. This project gives us the opportunity to help move the field forward and hopefully contribute to a more nuanced understanding of organisms.”

What’s the Buzz About Pollinators? Class Visits Local Apiary to Find Out

bees

Drew Burnett, kneeling, at right, gave Wesleyan students a tour of a local apiary, where they learned about the centrality of honeybees to our industrialized agricultural system. The students are pictured holding Drew’s Honeybees lip balm.

Students in a Sustainable Agriculture and Food Systems class recently stepped out of the classroom … and into beekeeping suits. The buzzworthy hands-on experience was part of a field trip to an apiary in Norwich, Conn.

“The course explores strategies to create a sustainable agriculture and food system,” said Rosemary Ostfeld ’10, visiting assistant professor of environmental studies, who teaches the class. Her students have already been gaining an understanding of some of the key environmental impacts associated with our agricultural system, and read Rachel Carson’s seminal Silent Spring. The purpose of the field trip on Sept. 18 “was to learn more about pollinators—specifically honeybees—and some of the reasons their populations have been declining in recent years,” Ostfeld said.

Hosting the students were beekeeper Drew Burnett and his assistant Curtis Witt. Burnett is the founder of Drew’s Honeybees, a honeybee-centric, all-natural, USDA organic skincare company. Drew’s Honeybees donates 20 percent of its profits to the State of Connecticut’s Agricultural Experiment Station to fund pioneering research into the causes of and solutions to Colony Collapse Disorder.

New IDEAS Lab Offers State-of-the-Art Digital Fabrication Tools

 Assistant Professor of the Practice Daniel MollerIDEAS clasroom

Daniel Moller, assistant professor of the practice in integrative sciences, is teaching Introduction to Design and Engineering inside the new IDEAS Lab this fall semester.

Equipped with 3-D printers, water-jet and laser cutters, computer-operated milling machines, and high-tech drills, saws, and workstations, Wesleyan’s new IDEAS Lab is on the “cutting edge” of digital fabrication.

Wesleyan’s new ProtoMAX water-jet cutter created this butterfly out of aluminum in 18 minutes.

This fall, the College of Integrative Sciences opened the adjoined classroom and makerspace in Room 40 of Exley Science Center. While it is currently used by students in the IDEAS (Integrated Design, Engineering & Applied Science) program, by spring 2020 the space should be open to the entire Wesleyan community.

“The space is the heart of our efforts to provide students with a facility to explore their ideas and create new projects,” said Francis Starr, IDEAS coordinator and professor of physics.

The IDEAS program prepares students to succeed at the intersection of design, the arts, and engineering. Students hone skills in identifying which scientific and engineering principles need to be understood to achieve design goals, and use computer-aided design (CAD) software and fabrication tools in the lab to create a solution for their design. Students also develop foundational knowledge in design and engineering by working in collaborative groups on project-based studies.

While much of the new lab equipment was purchased by the University, lighting solutions company OSRAM, based in Beverly, Mass., donated dozens of fabrication tools and parts to Wesleyan this summer. The lab’s professional-grade 3-D printer, computer numerical control router, and vortex dust collector were part of the donation, which collectively are valued at approximately $500,000.

“The donated items allow us to offer students access to a number of tools that they would otherwise not get a chance to experience,” said Professor of Physics Brian Stewart, who spearheaded the OSRAM donation. “We’re also moving closer to establishing an advanced lab in the Physics Department, so the donated vibration-free laser tables, hardware, and electronic equipment will serve as the nucleus of this exciting new departmental project.”

Learn more about IDEAS in this Wesleyan Magazine article. Follow the Wesleyan IDEAS Lab on Instagram.

Photos of the IDEAS Lab are below: (Photos by Olivia Drake)

Lopez shows off a vacuum forming tool, which is used to form plastic around a mold and create a permanent object. At left is a 3-D printer.

Shawn Lopez, College of Integrative Sciences makerspace coordinator, displays an object created by the IDEAS Lab’s vacuum forming machine, pictured at right. The tool heats and forms plastic around a mold and creates a permanent object. At left is a 3-D printer that “prints” a three-dimensional object based on a computer design.

IDEAS

Francis Starr speaks to Brian Stewart about a large 3-D printer that was donated by OSRAM. This machine can print objects with exceptionally high resolution in a wide variety of materials.

Lopez demonstrates how a laser cuts an object out of wood.

Lopez demonstrates how a laser cuts an object out of wood.

The 75-watt engraver uses a CO2 laser, pulsing at 2,500 cycles per second, to cut into a sheet of wood.

The lab’s water-jet cutter slices through flat sheets of metal, tile, stone, and plastic using 30,000 psi of water and garnet abrasive material.

The IDEAS Lab milling machine uses various drill bits to cut and carve 3-D objects from solid materials such as metal, wood or plastic.

The multi-axis computer numerical control router, or milling machine, uses various drill bits, as well as a 4th axis lathe attachment, to cut and carve 3-D objects from solid materials such as metal, wood, or plastic. After programming the paths using appropriate software, the process is almost entirely automated. “Most of our CNC machines are really designed for cutting material in two dimensions,” Lopez said. “What if you want to actually carve a piece of metal in three different dimensions? This mill is the kind of device that can actually do that.”

OSRAM donated multiple laboratory oscilloscopes, which are used to display and analyze the waveform of electronic signals. Three have already been installed in the Exotic Wave Lab managed by Fred Ellis, professor of physics. “Numerous research groups have already benefited through the acquisition of individual pieces of equipment: oscilloscopes, digital delay generators, and other hardware have satisfied needs or increased capabilities in most of the department’s experimental laboratories,” Stewart said. “This is particularly welcome as our ability to accommodate additional undergraduate students into our research labs is often limited by the availability of equipment for new or exploratory projects.”

In addition to digital fabrication machinery, OSRAM donated thousands of pieces of optical equipment to Wesleyan.

The IDEAS Lab is located on the ground floor of Exley Science Center.

Poulos Studies Endangered Grass on Texas-Mexico Border

Pictured third from right, Helen Poulos, adjunct assistant professor of environmental studies, gathers with the “Fescue Rescue” team at Maderas del Carmen Protected Area in Mexico. There, the scientists are studying Guadalupe fescue, an endangered grass species.

field sites in the Sierra del Carmens, Coahila Mexico

Helen Poulos, adjunct assistant professor of environmental studies, works at a field site in the Sierra del Carmens, Coahuila Mexico. In September 2017, the U.S. government determined that Festuca ligulata needed protected species status and designated it a critical habitat under the Endangered Species Act of 1973.

The rare Guadalupe fescue once thrived in abundance atop mountains spanning the Texas-Mexico border, however, the desert-growing perennial grass is now so endangered, it only flourishes in two locations on Earth.

The rapid population decline is leaving scientists puzzled.

“Developing an effective recovery plan is essential for protecting Guadalupe fescue, however, the lack of basic information about this species’ ecology is a serious barrier to that goal,” explained Helen Poulos, adjunct assistant professor of environmental studies. “Urgent action is needed to stabilize the two extant populations.”

This summer, under Poulos’s leadership, Wesleyan received a National Park Service Grant to study Festuca ligulata through the Southwest Borderlands Resource Protection Program. She joined a bi-national team of scientists known as “Fescue Rescue” to research the two isolated fescue populations in Texas’s Big Bend National Park and the Maderas del Carmen Protected Area in Coahuila, Mexico.

Said Poulos, a plant ecologist who has worked at desert borderland sites for more than a decade, “The Guadalupe fescue has become so endangered that this has become a significant national and international conservation concern.”

Backed by the NPS grant, the Fescue Rescue team will conduct onsite visits from October to mid-November 2019 during Guadalupe fescue seed maturation. Seeds will be collected during this time and transported to labs at Sul Ross State University in Texas and Universidad Autónoma Antonio Narro in Mexico. At these locations, scientists will germinate the seeds and grow their own fescue refugial populations for multiple research purposes.

“Together, they’ll provide a springboard for future plant population genetics, enrichment planting, and adaptive management research on both sides of the border,” Poulos said. “Such information is vital for elaborating site-specific management plans for the species on both U.S. and Mexican soils.”

They’ll study environmental variables, inventory seed production, identify key factors that promote reproductive viability, and ultimately establish refugial populations on both sides of the border.

Although virtually nothing is known about the environmental influences on the growth and reproduction of Guadalupe fescue, Poulos believes the fescue’s population decline is a result of multiple factors.

“Environmental factors that have likely negatively influenced the fescue populations include a recent shift to a hotter and drier climate, the genetic and demographic consequences of small population sizes and isolation, trampling by humans and pack animals, trail runoff, competition from invasive species, and fungal infection of seeds,” she said.

In addition, naturally occurring wildfires, which play an important role in rejuvenating ecosystems, are rare due to livestock grazing in the early 1900s and subsequent direct fire suppression continuing to the present. The remaining plants in the two disjunct populations are likely highly inbred and lack genetic diversity. This can threaten the capacity of populations to resist pathogens and parasites, adapt to changing environmental conditions, and colonize new habitats.

Poulos hopes to deliver her final reports to the National Park Service by summer 2020.

Undergraduates Share Summer Research

poster session

Ben Sullivan ’20 presents his poster titled “Tracking New York Times Coverage of Every Senator First Elected in the 1990s” during the Summer Program for Research in the Sciences Poster Session on July 25. His advisor is Logan Dancey, associate professor of government.

The Summe Program for Research in the Sciences culminated with a research poster session in the lobby of Exley Science Center, with more than 100 students participating.

The program, held May 29 to July 26, was open to frosh, sophomores and juniors currently enrolled at Wesleyan. Wesleyan science faculty members served as mentors for student research in their laboratories. In addition to the closing poster session, the students participated in weekly seminars and workshops, a symposium, and various social events. After the poster session, students displayed their posters in the hallways outside the introductory biology laboratories.