January 2, 2025—Fall semester ’24 updates

Happy new year! The lab had a fun and productive fall semester (and year!) and is looking forward to more in 2025!

Rachel Surprenant just joined the Tarhan Lab as a Yale Seessel Postdoctoral Fellow. Rachel recently completed her PhD at UC Riverside, where she investigated the morphology and taphonomy of Ediacaran tubular fossils. Welcome Rachel!

In September, Lidya, along with colleagues at Stanford, UC Riverside and Yale, was awarded a grant from the NSF Frontier Research in Earth Sciences program to explore the impact of early land plant evolution on the Earth system.

Also in September, members of the Tarhan Lab traveled to Anaheim, CA for GSA 2024! Lab members gave the following talks:

Lidya gave two invited keynote talks titled “Bioturbators—agents or recipients of warming-induced biogeochemical change?” and “How biogeochemically impactful was Skolithos piperock? New insights from Cambrian field data and geochemical modeling“.

Kate gave a talk titled “Assessing the relationship between bioturbation intensity and organic carbon preservation in middle Paleozoic sediments“.

Brian gave a talk titled “Bioturbation shapes marine nutrient cycling following the Permian-Triassic Mass Extinction“.

Ashley gave a talk titled “Interrogating paleoenvironmental and evolutionary patterns in bioturbation in upper Cambrian and Lower Ordovician strata of the Great Basin, USA“.

And Sydney gave a talk titled “New insights into early vascular land plants as geobiological agents of phosphorus weathering“.

Andrea continued working with Kate on conducting laboratory analyses of Devonian and Carboniferous core samples from the Appalachian and Great Basins to study bioturbation’s impact on seafloor biogeochemistry.

Core material!

In October and November, Maya participated in the RUBBLE Marine Expedition, which crossed the Atlantic from the Canary Islands to Fortaleza, Brazil. On this research cruise, she collaborated with colleagues from the Senckenberg Institute in Germany, the Polish Academy of Sciences, and the University of Lodz (Poland) to investigate benthic heterogeneity in the deep sea. Maya collected samples, observations, and X-ray images to assess the intensity and styles of bioturbation on the seafloor of the tropical Atlantic. This work was supported by the Yale Institute for Biospheric Studies. See below for photos from the cruise!

A few papers from the lab were also published this semester!

Ashley and Lidya, along with colleagues at Colorado College, Johns Hopkins, MIT and Yale, published a paper in Palaios describing a new mode of Ediacara-style fossilization, in which cementation of siltstone and sandstone fossil molds by early diagenetic clays was fostered by silica- and iron-rich porewaters, of Ediacaran tubular fossils from Nevada. This is Ashley’s first paper of her PhD, congratulations Ashley!

Lidya and colleagues, led by former Yale postdoc Moji Fakhraee (now faculty at UConn), published a review of the history of Earth’s sulfur cycle in Nature Reviews Earth and Environment.

Lidya, along with Tarhan Lab alum (now faculty at Peking University) Jiuyuan Wang and colleagues published a paper in Nature Geoscience on the importance of fostering international research collaborations in the earth sciences.

Lidya and Jiuyuan, along with colleagues at University of Miami and Yale, recently had a paper accepted to Chemical Geology investigating the impact of early diagenesis on stable strontium and lithium isotope signatures in modern marine carbonate sediments of the Bahamas.

Lastly, registration for the 18th International Ichnofabric Workshop (18IIW) is now live! The conference takes place from May 26-31, 2025 in Granada, Spain. The abstract deadline is January 15. Looking forward to seeing you there!

August 26, 2024—Summer ’24 updates

Tarhan Lab members are back from a variety of interesting summer activities!

Over the summer, Olmo has continued to investigate the effects of temperature and oxygen on some of the main components of the benthic fauna of Long Island Sound (see pictures of his bioturbation experiments below)!

Maya and Kate headed to the West Coast in late May and Early June for Maya’s fieldwork examining climate-driven changes in bioturbation. They collected bioturbation data from Pleistocene outcrops and modern tidal flats and were excited to see ghost shrimp, shore crabs, polychaetes, and bivalves in action!

Brian spent a second field season in Svalbard studying bioturbation and biogeochemical cycling across the Permian-Triassic transition, working with colleagues from Hamburg University in Germany, Nanjing University in China, and the University Centre in Svalbard. Along the way he saw two polar bears and found some Early Triassic marine reptile fossils. His field season was supported by a Yale Institute for Biospheric Studies (YIBS) dissertation improvement grant and a Paleontological Society student research grant.

Sydney participated in the International Geobiology Course hosted by Penn State! She spent two weeks doing field work in central Italy sampling biofilms from caves and springs, travertines, and rocks from OAE2, as well as a short sampling trip to Fayetteville Green Lake. The last three weeks of the course were spent analyzing samples in the labs at Penn State and learning various different analytical techniques commonly used in geobiology.

Sampling biofilms from sulfidic springs in Frasassi Gorge, Italy

The OAE2 black shale layer (“Bonarelli Level”)!

Thrombolites at Dead Man’s Point, Green Lake, NY

Ashley and Lidya went on two field expeditions as part of the NASA Exobiology Grant to better understand the impact of ocean chemistry on early animal communities in through the Ordovician. In June they did field work in Newfoundland with grant collaborators from Virginia Tech and Smith College and in August they went to central Idaho with collaborators from FSU, U Dayton, and JMU. In Idaho specifically they were looking at deeper basin bioturbation in shale lithofacies, and used biostratigraphy from collaborators to collect data on geochemical cycles for FSU and ichnofabric index and BPBI data for Yale. They learned a lot about graptolites and conodonts, including how to find them, from experts Daniel Goldman and Steve Leslie. They saw beautiful sights and wildlife, including moose, deer, and elk!

In August, Kate and Lidya spent a week on Anticosti Island in Quebec looking at trace fossils across the end-Ordovician extinction event with André Desrochers from the University of Ottawa and Pascale Daoust from McGill University.

Tarhan Lab members were also involved in mentorship and outreach for summer students!

Kate hosted a Yale undergraduate, Andrea Chow, for the summer. Andrea is helping with a project assessing the relationship between organic carbon burial and bioturbation in Middle Paleozoic sediments.

In July, Lidya and Maya taught an outreach session entitled “Behaviors of Seafloor Animals — Past, Present, and Future!” As part of the Yale Pathways to Science program, they welcomed high school students from the New Haven area to learn about marine bioturbation. In this hands-on session, students examined modern bioturbation from animals and sediments of Long Island Sound and worked with trace fossils from the Yale Peabody Museum collections.

Sydney worked with Yale Pathways to Science program high school student Cesar who was hosted by the Blake Lab and taught him about lab work, the phosphorus cycle, the phosphorus speciation technique, and coding and modeling.

Lidya, Kate and Olmo attended the 2024 North American Paleontological Convention (NAPC), and Kate presented a talk titled “A combined stratigraphic and ichnological approach to reconstructing the evolution of the sedimentary mixed layer in the Devonian of the Appalachian Basin.”

Lab members also had papers published this summer!

Brian and Lidya published a paper on reverse weathering during the Early Triassic led by collaborators at U Waikato and includes data from their field sites in Svalbard.

Lidya, former Tarhan Lab postdoc Sophie Westacott and collaborator Mingyu Zhao published a new paper in Palaeo-3 on the stratigraphic distribution and biogeochemical impacts of Cambrian Skolithos piperock.

Lidya and former Tarhan Lab PhD student Silvi published a paper in Geobiology on the role of authigenic mineralization in Ediacara-style fossil preservation.

Congratulations Brian, Silvi, Sophie, and Lidya!

Lidya was awarded Yale’s 2024 Arthur Greer Memorial Prize “in recognition of her groundbreaking research on the sedimentary record.” Congratulations, Lidya!

After a busy summer, the lab is also preparing to help organize conferences next year!

Save the date for the 3rd Geobiology Society Conference, which will be held in Banff, Canada from May 20-24, 2025:

The 18th International Ichnofabric Workshop: New trends in ichnofabric analysis will be held in Granada, Spain from May 26-31, 2025 (contact Olmo for more information!):

June 6, 2024—Spring semester updates

We’re excited to have visiting Postdoctoral Associate Olmo Miguez-Salas, who started working in the Tarhan Lab in April. Olmo is visiting the lab from the Senckenberg Research Institute in Frankfurt, Germany. His work focuses on examining how temperature changes and low-oxygen events affect bioturbation intensities of some Long Island Sound trace makers. He conducts experiments using environmental control chambers and aquarium systems. Moreover, these experiments aim to validate the past record of similar trace fossils that are recorded through thermal or anoxic events. You can read more about his work on his Google Scholar. Welcome, Olmo!

Members of the Tarhan Lab helped organize the 2024 Northeast Geobiology Conference at Yale, led by our very own Maya! The conference had over a hundred attendees who were treated  to a tour of the newly reopened Yale Peabody Museum of Natural History and a keynote talk by YIBS Bass Visiting Scholar Tim Lyons. Brian also gave an exciting talk on his recent work looking at bioturbation intensities and biogeochemical cycling before and after the Permo-Triassic mass extinction!

Brian giving his talk about Permo-Triassic bioturbation.

Kate visited the US Geological Survey’s Core Research Center in Denver, Colorado to log bioturbation data and collect samples. This is part of her work investigating the effect of bioturbation intensity and style on sediment geochemistry during the Middle Paleozoic. She also gave an invited talk at the University of Southampton and attended a workshop on spatial methods for analyzing the fossil record at Oxford University.

Lidya and Silvi attended AbSciCon in Providence, RI in May. Lidya gave a talk and Silvi presented a poster on fossil silicification.

In addition to all the activities, this past semester Tarhan lab members had many accomplishments!

Silvi defended her PhD in May and moved to Chile to start a position as a professor at Universidad de O’Higgins. Congratulations Dr. Silvi, we’re excited to see the amazing things you will do next!

Undergraduate researcher Dana graduated and will be starting a PhD in geology at MIT in the Fall with Lyle Nelson. She was also awarded the National Science Foundation Graduate Research Fellowship and the MIT Dean of Science Fellowship! Congratulations, Dana, we’ll miss you!

PhD students Brian and Sydney were both awarded YIBS research grants. Brian will use his grant to continue conducting fieldwork on Permo-Triassic bioturbation and biogeochemical cycling in Svalbard, and Sydney will use hers to run geochemical analyses on the samples she collected from Bathurst Island last summer for a project on early land plants and the phosphorus cycle. Congratulations Brian and Sydney!

Sydney was also awarded a Heidemarie Johnson Scholarship from The Paleontological Society to attend this year’s International Geobiology Course, and Brian was awarded a Paleontological Society Research Grant to continue working in Svalbard!

Kate was awarded the EPS department’s Hammer Prize for outstanding graduate students. Those who know Kate know that she is extremely inquisitive, creative, hard working, and devoted to both her research and the EPS community. Congratulations, Kate!

Last but not least, congratulations to Lidya, along with co-authors Shuang Zhang and Martin Solan, who published a paper last month in Current Biology titled “Global distribution and environmental correlates of marine bioturbation.” Their work uses machine learning techniques to create a global map of bioturbation intensities and identify which environmental and ecological factors best correlate with bioturbation type/intensity. This work has major implications for predicting how bioturbation changes under different climate/environmental scenarios. The research was also covered by the Yale News, and you can read the article here!

February 8, 2024—Winter updates

With the new year and new semester we have some updates from Tarhan Lab members!

Over winter break PhD student Ashley Rivas revisited the Arrow Canyon Range in southeast Nevada along with colleagues from Smith College and Virginia Tech. They went back to some previously measured sections to get bioturbation data, and did recon work for future field campaigns.

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Finally, members of the Tarhan Lab are involved in organizing the 2024 Northeast Geobiology Symposium which will be held at Yale on April 12-13. NE Geobio is a student- and postdoc-run conference held annually for over a decade and brings together geobiologists from the northeastern US and Canada. Registration is open and abstracts are currently being accepted until March 8. More details can be found on the conference website.

November 7, 2023—Fall ’23 semester

It has been a busy semester for the lab! 

First and foremost, this semester we welcomed two new members to the lab–Maya LaGrange Rao and Dana Polomski! Maya is a Yale Institute for Biospheric Studies (YIBS) Donnelley Postdoctoral Research Fellow who joins us after completing her PhD at University of Alberta. Maya will be working on comparing Pleistocene and modern bioturbation in Willapa Bay, WA, to better understand the response of coastal bioturbation to climate change. Dana is a senior undergraduate EPS major at Yale who is working on Mesozoic bioturbation with James and mid-Paleozoic bioturbation and its impact on sediment geochemistry with Kate. Welcome Maya and Dana!

Maya has already made significant headway on her project—in late September, Lidya and Maya visited the west coast for five days of fieldwork at Willapa Bay in southern Washington. Joined by Brette Harris and Murray Gingras from the University of Alberta, they conducted preliminary fieldwork examining Pleistocene intertidal flat deposits, which will be followed by a more extensive field campaign in spring 2024.

August 2, 2023—Tarhan Lab summer activities

Members of the Tarhan Geobiology lab have had a busy summer filled with field work, trips, and conferences!

Postdoc Sophie Westacott wrapped up her year with us at Yale and moved to Bristol, UK to start a postdoc continuing her work on the silica cycle in the modern and in deep time. Best wishes to Sophie in her new position!

In May, Lidya, Ashley, Kate, and Sydney spent two weeks in the Great Basin (southern Nevada and western Utah) studying bioturbation and trace fossils preserved in shallow-marine carbonates deposited during the late Cambrian to mid-Ordovician. They were joined by colleagues from Virginia Tech (Ben Gill) and Smith College (Sara Pruss) and their students as part of a NASA exobiology grant to study the geochemical and paleobiological conditions between two of life’s greatest radiations: the Cambrian Explosion and Great Ordovician Biodiversification Event. 

In June, Kate and Sydney continued working in the Great Basin for Kate’s PhD project searching for signs of bioturbation and the development of the marine sediment mixed-layer. They worked on Devonian and Carboniferous strata at several localities across southern and central Nevada and were partly joined by colleague Diana Boyer (Winthrop University) and her students.

In June, Silvi and Sam went on the department field trip to Greece and visited geological sites all over the country! They both continued on to the Goldschmidt geochemistry conference in Lyon, France, where Silvi presented her poster “The Role of Substrate and Seawater Geochemistry in Shaping the Fossilization of Earth’s Earliest Animal Communities.”

In July, Lidya and Sydney joined colleagues from Stanford (Erik Sperling and Emily Ellefson) and the Geological Survey of Canada (Keith Dewing) for an Arctic expedition to Bathurst Island, Nunavut to study Silurian-Devonian marine shales that capture geochemical conditions during the rise of early land plants. They collected hundreds of samples for a variety of geochemical analyses, saw a polar bear, and found plant fossils!

Last but not least, Kate’s undergraduate research was recently published in Palaeogeography, Palaeoclimatology, Palaeoecology! The title of her paper is “Appalachian Basin mercury enrichments during the Late Devonian Kellwasser Events and comparison to global records.” Link to the paper is here. Congratulations, Kate!