<?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>R.S. Oremland</dc:contributor>
  <dc:creator>M. C. Marvin-DiPasquale</dc:creator>
  <dc:date>1998</dc:date>
  <dc:description>&lt;div class="hlFld-Abstract"&gt;&lt;div id="abstractBox"&gt;&lt;p class="articleBody_abstractText"&gt;Methylmercury (MeHg) degradation was investigated along an eutrophication gradient in the Florida Everglades by quantifying&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;14&lt;/sup&gt;CH&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;14&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;production after incubation of anaerobic sediments with [&lt;sup&gt;14&lt;/sup&gt;C]MeHg. Degradation rate constants (&lt;i&gt;k&lt;/i&gt;) were consistently ≤0.1 d&lt;sup&gt;-&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and decreased with sediment depth. Higher&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;values were observed when shorter incubation times and lower MeHg amendment levels were used, and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;increased 2-fold as in-situ MeHg concentrations were approached. The average floc layer&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;was 0.046 ± 0.023 d&lt;sup&gt;-&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(&lt;i&gt;n&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;= 17) for 1−2 day incubations. In-situ degradation rates were estimated to be 0.02−0.5 ng of MeHg (g of dry sediment)&lt;sup&gt;-&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;d&lt;sup&gt;-&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt;, increasing from eutrophied to pristine areas. Nitrate-respiring bacteria did not demethylate MeHg, and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;addition partially inhibited degradation in some cases. MeHg degradation rates were not affected by PO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;3&lt;/sup&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;addition.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;14&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;production in all samples indicated that oxidative demethylation (OD) was an important degradation mechanism. OD occurred over 5 orders of magnitude of applied MeHg concentration, with lowest limits [1−18 ng of MeHg (g of dry sediment)&lt;sup&gt;-&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt;] in the range of in-situ MeHg levels. Sulfate reducers and methanogens were the primary agents of anaerobic OD, although it is suggested that methanogens dominate degradation at in-situ MeHg concentrations. Specific pathways of OD by these two microbial groups are proposed.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/es971099l</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>ACS</dc:publisher>
  <dc:title>Bacterial methylmercury degradation in Florida Everglades peat sediment</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>