Geochemistry and Biogeochemistry
Our research program studies the earth surface including chemical weathering, soil formation, and biogeochemical cycling. We focus on Critical Zone processes: that area of the earth's surface where lithosphere, hydrosphere, biosphere, and atmosphere intersect. We use isotopic and trace element geochemistry to understand how these processes impact landscape evolution, global elemental cycles, and ecosystem productivity.
New "Tools of the Trade" article by graduate student Layla Ghazi about Characterizing organic carbon with ramped pyrolysis oxidation:
New blog post by graduate student Layla Ghazi about the dirty "breath" of rocks:
Congratulations to Kaveh Siah! He successfully defended his M.S. dual degree in Soil Science and Forest Ecosystems and Society, co-advised by Julie Pett-Ridge and Steve Perakis. We wish him well as he continues his work in biogeochemical modeling and the University of New Hampshire for his Ph.D. program.
Layla Ghazi joined in on a field work excursion associated with NSF Award: EAR1758463 led by Dr. Eric Kirby (UNC-CH) in an effort to collect 10Be data in southern Oregon. Layla was able to help identify and coordinate several sites to collect data from in the Umpqua River.
Congratulations to PhD student Layla Ghazi who was recently awarded a NOSAMS internship from the Woods Hole Oceanographic Institution!! NOSAMS is the National Ocean Sciences Accelerator Mass Spectrometry Lab. This internship was awarded for Layla's proposal to work on "Using Ramped Pyrolysis Oxidation and 14C Analysis to Characterize the Composition of Particulate Organic Carbon Mobilized Through Two Contrasting Small Mountainous Rivers in the Pacific Northwest."
Katy Dynarski's paper "Decadal-scale decoupling of soil phosphorus and molybdenum cycles by temperate nitrogen-fixing trees" was published in Biogeochemistry
Thanks to funding from NSF GRFP GRIP for making this possible!
Matthew McClintock's paper "African dust deposition in Puerto Rico: Analysis of a 20-year rainfall chemistry record and comparison with models" was published in Atmospheric Environment
2 new papers:
(1) "Rock-eating" trees:
"Nitrogen-fixing red alder trees tap rock-derived
nutrients" was published in PNAS
Related News Release here:
Nitrogen-fixing trees 'eat' rocks, play pivotal role in forest health
(2) How rock type controls trace metal dynamics despite prolonged intense weathering:
"Underlying lithology controls trace metal mobilization during redox fluctuations" was published in Science of the Total Environment
2 new papers:
Liz King's paper "Reassessing the dissolved molybdenum isotopic composition of ocean inputs: The effect of chemical weathering and
groundwater" was published in Geology
Maria Chapela Lara's paper "The effects of lithology on trace element and REE behavior during tropical weathering" was published in Chemical Geology
We presented the early results from our research on georespiration in the Eel and Umpqua river basins at the annual Goldschmidt Meeting in Boston:
"Determining Rates and Mechanisms of Geologic Respiration at Watershed Scales"
2 new papers:
Potential for Iron Reduction Increases with Rainfall in Montane Basaltic Soils of Hawaii
Molybdenum isotope fractionation during adsorption to organic matter
Congrats to Liz King on successfully defending her PhD!
Our new paper shows widespread molybdenum limitation of nitrogen fixation:
Nutrient feedbacks to soil heterotrophic nitrogen fixation in forests
Check out our new "Science in 60"
Oregon Museum of Science and Industry Science Communication Fellow Elizabeth King unveiled her hands-on exhibit "Discovering Dirt: Hawaii"
Justin Hynicka's paper "Nitrogen enrichment regulates calcium sources in forests" was published in Global Change Biology
Elizabeth King's paper "Molybdenum sources and isotopic composition during early stages of pedogenesis along a basaltic climate transect" was published in Chemical Geology
Blog post: From the River to the Sea: Rare Metal Cycles and the Circle of Life
December 2015: AGU talks
Julie Pett-Ridge :“Biotic Nitrogen Enrichment Regulates Calcium Sources to Forests”
Monday, 14 December 2015 at 10:50 a.m.-11:05 a.m. Moscone West room 2008
Click here for more info
Elizabeth King :“Molybdenum Isotopes and Mass Balance During Earth Stages of Pedogenesis”
Monday, 14 December 2015 at 11:20 a.m. – 11:35 a.m. Moscone West room 2003
Click here for more info
November 2015: Elizabeth King on the radio! Listen here to Liz talk about her research using molybdenum isotopes as a paleoredox tracer.
October 2015: Elizabeth King spent the month at the University of Georgia running redox fluctuation experiments on soils she collected from the Luquillo Critical Zone in Puerto Rico as part of the CZO Summer Intern Fellowship she was awarded this past year.
Winter 2015: Elizabeth King was chosen as an NSF representative for the WUN Summer School at the University of Western Australia looking at the effects of climate change on soils. Check out the video of her experience here!