[Enviro-lunch] Enviro-Lunch Seminar TODAY 12-1:15PM PST! Michael Philben, PhD of Hope College "Rethinking carbon and nitrogen isotope fractionation during soil organic matter decomposition"

[Anna Jurusik]

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Rethinking carbon and nitrogen isotope fractionation during soil organic matter decomposition,  Michael Philben, PhD, from Hope College

Hello everyone!

We cordially invite you to join us today, Monday September 19th at 12:00PM-1:15PM PST via Zoom for our Enviro-Lunch seminar series with guest speaker Dr. Michael Philben from Hope College!

Join us here! https://ucmerced.zoom.us/j/85854124987

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                        Dr. Michael Philben

Title: Rethinking carbon and nitrogen isotope fractionation during soil organic matter decomposition

Abstract: The stable isotope ratios of C and N are potentially powerful tools for tracking the turnover of both elements. The enrichment of the heavier element (13C and 15N) with increasing depth is commonly observed in soil profiles, which is often attributed to a small fractionation of C and N isotopes during organic matter decomposition. In this talk I will present two studies that challenge the hypothesis that decomposition fractionates these isotopes, both focused on organic horizon soils from the Newfoundland and Labrador Boreal Ecosystem Latitudinal Transect (NL-BELT). To test C isotope fractionation, we measured the C isotope mass balance of these soils in both field and laboratory experiments. Neither of the major C fluxes (CO2 via soil respiration or leached DOC) were significantly depleted in 13C and therefore cannot explain the enrichment of 13C with depth in the soil profile. To test N isotope fractionation, we measured the N isotope ratios of hydroxyproline, a plant biomarker that is not resynthesized by microbes in the soil. While other amino acids became enriched in 15N with decomposition, hydroxyproline did not, indicating a lack of N isotope fractionation during organic N mineralization. These results challenge our conventional interpretation of C and N isotope ratios in soils, but present new opportunities to rethink the meaning of these stable isotope signals.


About Michael Philben, Ph.D. Mike Philben received a BA from Northwestern University in Earth and Planetary Science with a minor in Chemistry. He went on to complete his PhD in the Marine Science Program at the University of South Carolina, using the biochemical composition of organic matter to interpret how peatlands responded to past episodes of climate change.

Mike completed two postdocs after receiving his PhD. The first was with Sue Ziegler at Memorial University of Newfoundland examining boreal forest carbon and nitrogen cycle responses to climate change along a latitudinal gradient. The second was at Oak Ridge National Laboratory on the Next Generation Ecosystem Experiments-Arctic, focused on incorporating permafrost ecosystems into Earth system models. He is currently an Assistant Professor at Hope College in Holland, Michigan in the Departments of Geology/Environmental Science and Chemistry.

He is a native of Redding, CA and misses the Golden State dearly this time of year. He enjoys spending time with his 16-month old daughter Lily and his 6-year old hound dog Watson.


Join us here! https://ucmerced.zoom.us/j/85854124987

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Thank you so kindly to our last week's speaker, Dr. Chelsea Arnold of UC Merced and CalTeach for an amazing talk "I Don’t Even Know What Questions to Ask...Using Inquiry-Based Instruction to Promote Interest and Self Efficacy in Science"!


We’ll "see" you there!



Kind regards,

Enviro-lunch coordinators Anna Jurusik and Teamrat Ghezzehei, PhD.

ESS-190 coordinators Jorge Armando Montiel Molina, PhD., Carolin Frank, PhD., and Justin Yeakel, PhD.


About Enviro-lunch


Subscribe to our listserv here! https://lists.ucmerced.edu/mailman/listinfo/enviro-lunch


Fall 2022 Line-up (in progress)

Date

Speaker

Affiliation

9/12/22

Chelsea Arnold

University of California Merced

9/19/2022

Michel Philben

Hope College

9/26/2022

Jon Rebman

The Nat, San Diego Natural Hustory Museum

10/3/2022

TBD

TBD

9/19/2022

Michel Philben

Hope College

10/10/2022

Jason Diogo Pereire Bezerra

Instituto de Patologia Tropical e Saúde Pública

10/17/2022

Rose Shilito

Desert Research Institute; Army Research Laboratory

10/24/2022

TBD

TBD

10/31/2022

TBD

TBD

11/7/2022

TBD

TBD

11/14/2022

Safeeq Khan

University of California Merced

11/21/2022

Tetsu Tokunaga

Lawrence Livermore National Laboratory

11/28/2022

Sheng Wang

University of Illinois Urbana-Champaign

12/5/2022

Rebecca Abney

University of Georgia


What: An informal and collegial session where faculty, visiting scholars, postdoctoral researchers, staff, and students have the opportunity to discuss their past and/or current research, and more. This year we welcome 80 undergraduate students enrolled in ESS-190 to join the conversation! https://soilphysics.ucmerced.edu/envirolunch.html<https://urldefense.com/v3/__https:/soilphysics.ucmerced.edu/envirolunch.html__;!!DZ3fjg!_cxaM91btptMGOIdckdP0yK2VWD18dbs_kPpkRQLR3FZmy83nHN6kQrTlBj8kgQyYhRhRGMvQcf8lPfl6L6Jqq1qdg$> (website under construction, please pardon any errors)

When: Mondays 12:00p-1:15 pm (PST)

Where: We will host Enviro-Lunch virtually via ZOOM this semester

Who: Our audience typically spans across natural sciences from faculty, students, and staff, but also attracts engineers, social scientists, and more.

How: A ~30-40 min for presentation with ~15-20 min for Q&A/discussion over Zoom. This year we are coordinating with ESS-190, an undergraduate seminar series that will interface with the seminar. (note: only ESS-190 students will meet in person)

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