<div dir="ltr"><div>Hi all,</div><div><br></div><div>Just forwarding this seminar</div><div><br></div><div>-Pete<br></div><div><br></div><div><br></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><p class="MsoNormal"><a name="SignatureSanitizer_m_3910901674682384102__MailAutoSig"><span style="font-size:9.0pt;color:#1f497d">Peter M. Homyak, Ph.D. (he/him)</span></a></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d">Assistant Professor of</span></span></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d">Ecosystem and Soil Microbial Processes</span></span></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d">Associate Editor: </span></span><a href="https://www.elementascience.org/" target="_blank"><span><span style="font-size:9.0pt;color:blue">Elementa</span></span><span></span></a><span><span style="font-size:9.0pt;color:#1f497d"></span></span></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d">Dept. of Environmental Sciences</span></span></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d">University of California, Riverside</span></span></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d">900 University Ave</span></span></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d" lang="ES-CO">Riverside, CA 92521</span></span></p><p class="MsoNormal"><span></span><a href="mailto:Phomyak@ucr.edu" target="_blank"><span><span style="font-size:9.0pt;color:blue" lang="ES-CO">Phomyak@ucr.edu</span></span><span></span></a><span><span style="font-size:9.0pt;color:#1f497d" lang="ES-CO"></span></span></p><p class="MsoNormal"><span><span style="font-size:9.0pt;color:#1f497d">(951) 827-2358 | 312 Sci Lab I</span></span></p><p class="MsoNormal"><span></span><a href="http://petehomyak.weebly.com/" target="_blank"><span><span style="font-size:9.0pt;color:blue">http://petehomyak.weebly.com</span></span><span></span></a><span><span style="font-size:9.0pt;color:#1f497d"> </span></span></p><span></span><p class="MsoNormal"> </p></div></div></div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">---------- Forwarded message ---------<br>From: <b class="gmail_sendername" dir="auto">Daniel Hirmas</b> <span dir="auto"><<a href="mailto:daniel.hirmas@ucr.edu">daniel.hirmas@ucr.edu</a>></span><br>Date: Fri, Mar 25, 2022 at 10:04 PM<br>Subject: [Envisci-all] ENSC Seminar on Wed, Mar 30 @3:00 PM<br>To: <a href="mailto:envisci-all@lists.ucr.edu">envisci-all@lists.ucr.edu</a> <<a href="mailto:envisci-all@lists.ucr.edu">envisci-all@lists.ucr.edu</a>><br></div><br><br>
<div>
<b>Speaker:</b> Dr. Scott D. Wankel, Woods Hole Oceanographic
Institution, Marine Chemistry and Geochemistry Department<br>
<b>Time/Location:</b> Wednesday, March 30, 2022 @3:00 PM - 3:50 PM,
MSE 103<br>
<br>
You're invited!<br>
<br>
<b>Title:</b> Intricate
coupling of carbon, nitrogen and iron redox cycling underlying the
biogeochemical dynamics of N<sub>2</sub>O
<br>
<br>
<b>Abstract:</b> Over century long timescales, the
climatic forcing of nitrous oxide (N<sub>2</sub>O)
dwarfs that of carbon dioxide. Although increasing atmospheric
levels
are linked to excess nitrogen loading and consequent formation via
microbially mediated pathways, factors regulating the emission of N<sub>2</sub>O
to the atmosphere remain difficult to predict and the global N<sub>2</sub>O
budget remains poorly constrained. In large part, these challenges
stem from the fact that a diverse number of N<sub>2</sub>O
production pathways may be at work, especially in environments
hosting dynamic redox conditions - and thus disentangling their
relative roles in regulating N<sub>2</sub>O
is challenging. As coastal ecosystems are especially subject to
elevated nitrogen loading, we have been focusing investigations on
better understanding the controls on N<sub>2</sub>O
production mechanisms in intertidal sediments using a variety of
novel isotopic approaches. Surprisingly, initial findings have
indicated that under elevated nitrate loading, increased emissions
of
N<sub>2</sub>O
are not mediated by direct bacterial activity, but instead appear to
be largely catalyzed by fungal denitrification and/or abiotic
reaction with reduced iron (chemodenitrification). <br>
Expanding on these findings,
results from lab experiments focused on non-traditional production
pathways demonstrate high potential for cryptic cycling processes
under dynamic redox oscillations and shed some new light on factors
controlling kinetics, yields, and isotopic composition of product
N<sub>2</sub>O.
As both fungal and chemodenitrification typically exhibit N<sub>2</sub>O
yields far greater than bacterial production, even small levels of
their activity could produce disproportionately large amounts of N<sub>2</sub>O,
suggesting the possibility of their potentially substantial, yet
widely overlooked, role especially in coastal ecosystem N<sub>2</sub>O
fluxes. Finally, these findings may help to explain the notoriously
high variability of environmental N<sub>2</sub>O
fluxes, which may in part be driven by spatial and temporal
heterogeneity in organic matter respiration by fungi and the redox
cycling of iron.
<br>
<br>
[flyer attached]<br>
<br>
View upcoming seminars: <a href="https://envisci.ucr.edu/news-seminars" target="_blank">https://envisci.ucr.edu/news-seminars</a><br>
<br>
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<td colspan="2" style="padding-bottom:5px;color:#747474;font-size:14px;font-family:Arial,Helvetica,sans-serif"><br>
Daniel Hirmas</td>
</tr>
<tr>
<td colspan="2" style="color:#2282e8;font-size:12px;font-family:Arial,Helvetica,sans-serif"><i>Associate
Professor of Pedology and Graduate Advisor for
Continuing Students</i></td>
</tr>
<tr>
<td colspan="2" style="color:#2282e8;font-size:12px;font-family:Arial,Helvetica,sans-serif">Department of
Environmental Sciences</td>
</tr>
<tr>
<td colspan="2" style="color:#2282e8;font-size:12px;font-family:Arial,Helvetica,sans-serif">University of
California - Riverside</td>
</tr>
<tr>
<td style="vertical-align:top;width:20px;color:#a58e28;font-size:12px;font-family:Arial,Helvetica,sans-serif" width="20" valign="top">A:</td>
<td style="vertical-align:top;color:#2282e8;font-size:12px;font-family:Arial,Helvetica,sans-serif" valign="top">2228A Geology Building</td>
</tr>
<tr>
<td style="vertical-align:top;width:20px;color:#a58e28;font-size:12px;font-family:Arial,Helvetica,sans-serif" width="20" valign="top"> </td>
<td style="vertical-align:top;color:#2282e8;font-size:12px;font-family:Arial,Helvetica,sans-serif" valign="top">Riverside, CA 92521-0424</td>
</tr>
<tr>
<td style="vertical-align:top;width:20px;color:#a58e28;font-size:12px;font-family:Arial,Helvetica,sans-serif" width="20" valign="top">P:</td>
<td style="color:#2282e8;font-size:12px;font-family:Arial,Helvetica,sans-serif">(951) 827-2019</td>
</tr>
<tr>
<td style="vertical-align:top;width:20px;color:#a58e28;font-size:12px;font-family:Arial,Helvetica,sans-serif" width="20" valign="top">E:</td>
<td style="vertical-align:top;color:#2282e8;font-size:12px;font-family:Arial,Helvetica,sans-serif" valign="top"><a href="mailto:daniel.hirmas@ucr.edu" style="color:#2282e8;text-decoration:none;font-weight:normal;font-size:12px" target="_blank">daniel.hirmas@ucr.edu</a></td>
</tr>
</tbody>
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</div>
</div>
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