<div dir="ltr">Hello all, <div><br></div><div>Please join us for Ph.D. defense of Rebecca Abney. </div><div>
<p class="MsoNormal"><b><span style="font-size:11pt;font-family:'Times New Roman'"><br></span></b></p><p class="MsoNormal"><span style="color:windowtext;font-size:11pt;text-indent:0in"><b><font face="arial, helvetica, sans-serif">The role of erosion in soil organic matter and
pyrogenic carbon dynamics in fire-prone temperate forests</font></b></span></p><p class="MsoNormal"><span style="color:windowtext;font-size:11pt;text-indent:0in"><br></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'">Rebecca Abney<span></span></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'">Environmental Systems<span></span></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'">Adviser: Asmeret Asefaw Berhe<span></span></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'"><span> </span></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'">Date: 5/24/17 | Time: 10 AM | Location: SE2 –
302<span></span></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'"><span> </span></span></p>
<p class="MsoNormal"><b><span style="font-size:11pt;font-family:'Times New Roman'">Abstract<span></span></span></b></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'"><span> </span></span><span style="font-family:'Times New Roman';font-size:11pt">Wildfire and erosion are major perturbations to
the carbon cycle in eroding Sierra Nevada temperate forest landscapes. Pyrogenic
carbon (PyC) is formed due to incomplete combustion during fires, and is an
important component of the soil carbon sink due its relatively longer turnover
times in soil and susceptibility to erosion forces. Erosion of PyC and other
soil organic matter fractions was monitored after two wildfires: the Gondola
Fire, South Lake Tahoe and the Rim Fire, Yosemite National Park. Significant
and preferential erosion of PyC was found after the fires, in addition to
leaching down into the soil profile. The preferential erosion of PyC, and
overall quality of the soil and eroded sediments were controlled by burn
severity. To assess the fate of PyC in eroding and depositional landform
positions, chars formed at different temperatures were incubated in the same
soil collected from different landform positions. Both charring temperature and
landform position played significant roles in controlling soil respiration,
with the lower charring temperatures and the soil from the depositional
landform position having much higher respiration than higher temperature chars
and the soil from the eroding landform position. The post-fire erosional
transport of PyC can act as a major control on its long-term fate in soil. By
modeling the difference between including eroding and depositional landform
positions in PyC decay models, this can introduce error in measured turnover
times of up to 150 years. Including erosion as a mechanism for loss and gain of
PyC in eroding and depositional landform positions, respectively, is critical
for accurate accounting of PyC within the soil cycle. Understanding the
controls of erosion of PyC allows land managers to mitigate erosional loss to
enhance soil carbon storage.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'"><span> </span></span></p>
<p class="MsoNormal"><b><span style="font-size:11pt;font-family:'Times New Roman'">Biography<span></span></span></b></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:'Times New Roman'"><span> </span></span><span style="font-family:'Times New Roman';font-size:11pt">Rebecca graduated with a Joint Honours
Bachelor’s of Science in Environmental Biology and Physical Geography from St.
Andrews in Scottland. While studying there, she worked on research projects on
the impacts of land use and land use change on soil carbon cycling through a
transect in the Peruvian Andes. Her current research focuses on the interactive
roles that fire and erosion play as controls on soil carbon cycling. Her
projects include working on the Gondola Fire, near South Lake Tahoe and the Rim
Fire in Yosemite National Park. While studying at UC Merced, Rebecca has given
talks on her work at the American Geophysical Union annual meeting in both 2015
and 2016, in addition to a Critical Zone Observatory conference.</span><span style="font-family:'Times New Roman';font-size:11pt"> </span></p>
</div><div><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><span style="font-size:12px;color:rgb(121,121,121);font-family:Avenir-Roman">Cheers, </span><br></div><font color="#797979" face="Avenir-Roman" style="font-size:12px">Asmeret<br><br>---------------<br>Asmeret Asefaw Berhe<br></font><span style="font-size:12px;color:rgb(121,121,121);font-family:Avenir-Roman">Associate Professor, Soil Biogeochemistry</span><br style="font-size:12px;color:rgb(121,121,121);font-family:Avenir-Roman"><br style="font-size:12px;color:rgb(121,121,121);font-family:Avenir-Roman"><span style="font-size:12px;color:rgb(121,121,121);font-family:Avenir-Roman">Life and Environmental Sciences</span><font color="#797979" face="Avenir-Roman" style="font-size:12px"><br>University of California, Merced<br><br>Office phone: (209) 228-4712<br>E-mail: AABerhe@UCMerced.edu<br>Web: <a href="http://www.aaberhe.com/" target="_blank">http://www.aaberhe.com</a> </font><br></div></div></div></div></div>
</div></div>