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During the Summer 2021, graduate student Andy Marquez and post doc Murray Duncan traveled to the Friday Harbor Labs in the San Juan Islands of WA for three months to conduct respirometry experiments on various marine invertebrate species. Their primary goal was to explore how ocean warming and deoxygenation synergistically affect the biogeography and body size of marine ectotherms.

Huge congratulations to Judi Sclafani, who was awarded an NSF Postdoctoral Fellowship to move to UC Davis to work on Paleozoic brachiopod evolution and ecology. Congratulations also to Richard Stockey for being awarded our department's Cenntenial TA Teaching Award (based on his work over many years designing labs and working as head TA for Introduction to Geology) and to Sam Ritzer for being awarded the Harriet Benson award. 

In collaboration with Lizzy Trower (Univ. of Colorado; who led the paper), Justin Strauss (Dartmouth), and Woody Fischer (Caltech), we have published a paper investigating silica levels in early Paleozoic oceans. The paper studied samples collected from the Road River Group in Yukon, Canada, and used SIMS analysis of silicon isotopes from co-eval radiolarians and sponge spicules to infer dissolved silicon levels.

Historical Geobiology graduate students Tom Boag and Rich Stockey, along with Payne group member Will Gearty (all co-first authors) have published a paper in Current Biology looking at the relationship between global temperatures and the latitudinal diversity gradient. A news article on the paper can be found here. In the modern ocean, the highest diversity is found in the tropics.

First year doctoral student Andy Marquez has received the Graduate Research Fellowship from the National Science Foundation--congratulations Andy!!!

The first paper from the Sedimentary Geochemistry and Paleoenvironments Project (SGP) has been published early online at Geochemical Perspectives Letters. The paper, which is available here, was led by Alex Lipp and Oliver Shorttle, and investigated changing records of provenance and weathering through geologic time.

So we can't really count this as work from the lab, but the paper is so cool it has to be highlighted. Post-doc Murray Duncan has recently published work from his Phd thesis using the Metabolic Index to demonstrate how variable oxygen and temperature conditions set range limits for the Roman Seabream in South Africa. These analyses also predict how global change will likely affect its range in the future. The paper is published here in Conservation Physiology.

In collaboration with colleagues at Yale University and many other institutions, we were involved in a paper examining how uranium isotopes fractionate in ferruginous conditions (or more broadly, anoxic but non-sulfidic settings). The paper, published in Global Biogeochemical Cycles, was lead by Devon Cole, and can be accessed here.

In the lab's second Zoom defense, Tom Boag successfully defended his doctoral thesis on "The role of ecophysiology and paleoenvironmental dynamics in the Ediacaran biostratigraphic record." Tom worked on the paleontology, stratigraphy, geochronology, and carbon isotope chemostratigraphy of Ediacaran successions in the Wernecke Mountains, Yukon and Cariboo Mountains, British Columbia. These studies have refined our understanding of the temporal and environmental appearance of Ediacaran fossils in these successions and in the global record.

Dan Mills has published a review paper focusing on the temporal origins of phagocytosis and the implications for the Earth system. This paper is published in a theme volume based on a wonderful Royal Society meeting organized by Tim Lenton, Rachel Wood, Phil Donoghue, and others that Dan and Erik Sperling attended in September. The paper goes through the various possibilities for the temporal origins of eukaryogenesis, phagotrophy, and eukaryovary, and dissects the implications of each scenario.

One of the biggest conundrums of the Neoproterozoic is the cause of the 'Shuram' carbon isotope excursion, the largest negative carbonate carbon isotope excursion in the geologic record. In collaboration with colleagues at Yale, MIT and Dartmouth, we have helped produced new radiometric constraints on the Shuram excursion.

Two papers from the lab have recently come out on Mesoproterozoic redox conditions and organic carbon burial. First, Malcolm Hodgskiss completed a sedimentary geochemical study of the ~1.1 billion year old Arctic Bay Formation, Baffin Island, Nunavut, Canada. The formation is intriguing as it contains several hundred meters of ~10 weight percent total organic carbon. When corrected for thermal maturity, this formation originally contained many times more organic carbon than the richest source rocks in the productive Gulf of Mexico and west african margin petroleum systems.

While the first round of historical geobiology grad students are defending, that means the second wave is starting up. This summer we welcome Andy Marquez to the lab! Andy completed his undergraduate research on bivalve life history and ecology, and then worked in our Lab as a research assistant in summer 2019 (at Friday Harbor and the Hakai Institute) and in the fall on campus. He is interested in a variety of topics related to ancient, Pleistocene and future marine global change, and we look forward to seeing what he accomplishes!~

Posted 6/24/2020

Malcolm Hodgskiss successfully defended his doctoral degree on June 1st and became the first Phd graduate of the Historical Geobiology Lab! And for good measure, he won the department's Oustanding Graduate Student Award for the thesis. Congratulations Malcolm! The only downside was the defense had to be over Zoom rather than in person, although on the plus side it was great to see all of Malcolm's colleagues join in from around the world to hear about his work on the Orosirian (Paleoproterozoic) Period.

A new paper by Malcolm Hodgskiss detailing the carbon isotope chemostratigraphy of the Paleoproterozoic Labrador Trough has been published in the Canadian Journal of Earth Sciences. Malcolm, along with colleagues at McGill University, had to battle epic insects, structure, and lack of exposure, but ultimately prevailed with a new view of the Lomagundi-Jatuli excursion in this region. 

The Ordovician-Silurian extinction was the first major mass extinction of the Phanerozoic, yet its cause(s) remain debated. A new paper by Richard Stockey, published in Nature Communications, demonstrates that oceans spanning the Ordovician-Silurian boundary and through the first several million years of the Silurian had extensive regions that were anoxic and sulfidic, and that these low-oxygen oceans correlate with lower diversity in the fossil record. The paper used a novel Monte Carlo framework to better account for uncertainty in metal isotope mass balance models. 

A new paper by lab members Dan Mills and Erik Sperling has been published in Geobiology. This paper stemmed from the 'Point-Counterpoint' format debate at the Banff Geobiology Conference in 2017 between Sperling, Mills and Chris Reinhard, and the ideas from this discussion were then fleshed out in collaboration with Devon Cole, Doug Erwin, Noah Planavsky and Susannah Porter in a group discussion at the Santa Fe Institute.

Seven members from the Historical Geobiology Lab headed to San Diego for the Ocean Sciences conference. This was a great opportunity to learn about current research in oceanography and present our results to the modern oceanography crowd!

Posted 2/20/20

Iron speciation is one of our most robust proxies to understand the redox conditions of ancient water columns. This paper by Slotznick et al. (with lab members Erik Sperling and Austin Miller, as well as other collaborators at UC Berkeley, University of Utrecht, and University of Oxford) used magnetic techniques and XRD to probe the specificity of extractions used in iron speciation. The analyses confirmed the specificity of many of the extractions but revealed that the oxalate extraction mainly targets iron-rich clays such as berthierine and chamosite.

The lab welcomes Dr. Murray Duncan (Phd: Rhodes University) to work on a project funded by the Stanford Woods Institute. The project, in collaboration with Dr. Fio Micheli and Dr. Chris Lowe at Stanford's Hopkins Marine Station, explores using the Metabolic Index to predict the future habitable range of abalone and urchins in the NE Pacific ocean. Murray's research website can be found here:

 Posted 1/16/2020