ARNDT SCHIMMELMANN Senior Scientist | Organic Geochemistry and Chemical Oceanography
Arndt Schimmelmann’s international team of sci-
entists from Vietnam, Germany, and Indiana Uni-
versity identified subterranean microbes in caves
to voraciously consume the strong greenhouse
trace gas methane from air. Cave air typically ex-
changes with the atmosphere on short time scales.

Methane depletion in cave air on several conti-
nents indicates that the subterranean microbial
sink for methane is substantial enough to warrant
inclusion in global greenhouse gas modeling. In
contrast, laboratory experiments at Indiana Uni-
versity with strong radiation from radon isotopes
excluded the possibility that elevated natural ra-
dioactivity in caves can significantly contribute to
oxidation of methane in air.

Furthermore, Schimmelmann’s team continues
to develop remediation strategies to mitigate
radiation geohazards in mud-built homes in de-
veloping countries (see website: http://eosvnu.

net/projects/mud-built-homes/). Outreach ac-
tivities in mountain villages established person-
al contacts and reliable logistic support for our
research. As a third collaborative research project with
Vietnam National University in Hanoi, the lam-
inated sediment from a volcanic maar lake in
central Vietnam near Pleiku is being explored as a geological ar-
chive for prehistorical monsoon strength. The record of distinct
flood layers of the past can be radiocarbon-dated and may offer a
reliable statistical basis to judge the effects of climate change on
modern precipitation patterns in central Vietnam.

Two images from sediment coring activities in a central Vietnamese maar lake. The image
on the left shows our mobile coring platform where inner tubes from trucks provide flota-
tion. The entire platform with anchors cost only about $150 and worked extremely well.

We pulled 20 wonderful sediment cores from up to 21 m water depth with penetration
into sediment of up to 3.5 meter. At one time we needed a special heavy-duty core catcher.

On the right, a local machine shop in Pleiku lathed a core catcher for us from an old rusty
artillery shell at a few hours notice. In Vietnam everything is possible if you know your
way around. Our Vietnamese colleagues are experts in improvising.

LAURA WASYLENK I Associate Professor of Geological Sciences | Biogeochemistry of Metals
Laura Wasylenki was on sabbatical in 2016-17,
spending seven months at Stanford Universi-
ty and three months at École Polytechnique
Fédérale de Lausanne in Switzerland. She is in-
vestigating mineral-fluid reactions that attenuate
the migration of toxic heavy metals in soils and
near-surface groundwater. At the Stanford Syn-
chrotron Radiation Lightsource, she shone bright
beams of X-rays onto samples of iron and manga-
nese oxyhydroxide particles that she had loaded
with small amounts of tungsten, a likely carcino-
gen that has been widely introduced to the envi-
ronment during weapons production and testing.

She is studying the molecular-scale mechanisms
by which adsorption to common soil particles
can immobilize this toxic metal. She plans to
test some of the new knowledge derived in the
laboratory on a tungsten-contaminated field site
in SW Indiana with new graduate student Coley
Smith. In Switzerland, Wasylenki began a
collaboration with an environmental micro-
biology group interested in molecular-scale mechanisms
of uranium immobilization. While in Switzerland, she also
made time to observe with great joy plenty of steeply dip-
ping Jurassic carbonates adorned with Late Holocene gla-
ciers and was joined on one occasion by former student
Michael Haluska, M.S. ’15.

Wasylenki in the Lauterbrunnen
Valley with Jungfrau in the center
and Eiger on the left.

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