<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>T.L. Connell</dc:contributor>
  <dc:contributor>L.G. Miller</dc:contributor>
  <dc:contributor>R.S. Oremland</dc:contributor>
  <dc:contributor>R.S. Jellison</dc:contributor>
  <dc:creator>S.B. Joye</dc:creator>
  <dc:date>1999</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The oxidation of ammonia (NH&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;) and methane (CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;) was investigated in an alkaline saline lake, Mono Lake, California (U.S.A.). Ammonia oxidation was examined in April and July 1995 by comparing dark&amp;nbsp;&lt;/span&gt;&lt;sup&gt;14&lt;/sup&gt;&lt;span&gt;CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;fixation rates in the presence or absence of methyl fluoride (MeF), an inhibitor of NH&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;oxidation. Ammonia oxidizer‐mediated dark&amp;nbsp;&lt;/span&gt;&lt;sup&gt;14&lt;/sup&gt;&lt;span&gt;CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;fixation rates were similar in surface (5–7 m) and oxycline (11–15 m) waters, ranging between 70–340 and 89–186 nM d&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;, respectively, or 1–7% of primary production by phytoplankton. Ammonia oxidation rates ranged between 580–2,830 nM d&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;in surface waters and 732–1,548 nM d&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;in oxycline waters. Methane oxidation was examined using a 14 CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;tracer technique in July 1994, April 1995, and July 1995. Methane oxidation rates were consistently higher in July, and rates in oxycline and anaerobic bottom waters (0.5–37 and 7–48 nM d&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;, respectively) were 10‐fold higher than those in aerobic surface waters (0.04–3.8 nM d&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;). The majority of CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;oxidation, in terms of integrated activity, occurred within anoxic bottom waters. Water column oxidation reduced the potential lake‐atmosphere CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;flux by a factor of two to three. Measured oxidation rates and water column concentrations were used to estimate the biological turnover times of NH&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;and CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;. The NH&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;pool turns over rapidly, on time scales of 0.8 d in surface waters and 10 d within the oxycline, while CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;is cycled on 10&lt;/span&gt;&lt;sup&gt;3&lt;/sup&gt;&lt;span&gt;‐d time scales in surface waters and 10&lt;/span&gt;&lt;sup&gt;−2&lt;/sup&gt;&lt;span&gt;&amp;nbsp;time scales within oxycline and bottom waters. Our data suggest an important role for NH&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;oxidation in alkaline, saline lakes since the process converts volatile NH&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;to soluble NO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;&lt;span&gt;, thereby reducing loss via lake‐atmosphere exchange and maintaining nitrogen in a form that is readily available to phyto‐plankton.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.4319/lo.1999.44.1.0178</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Wiley</dc:publisher>
  <dc:title>Oxidation of ammonia and methane in an alkaline, saline lake</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>