<?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>D. Toczydlowski</dc:contributor>
  <dc:creator>Robert Stottlemyer</dc:creator>
  <dc:date>1999</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The Upper Great Lakes receive large amounts of precipitation-NH&lt;/span&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and moderate NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;inputs. Increased atmospheric inorganic N input has led to concern about ecosystem capacity to utilize excess N. This paper summarizes a 5-yr study of seasonal N content and flux in precipitation, snowpack, forest floor, and streamwater in order to assess the source of inorganic N outputs in streamflow from a small boreal watershed. Average precipitation N input was 3 kg ha&lt;/span&gt;&lt;sup&gt;-1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;yr&lt;/span&gt;&lt;sup&gt;-1&lt;/sup&gt;&lt;span&gt;. The peak snowpack N content averaged 0.55 kg ha&lt;/span&gt;&lt;sup&gt;-1&lt;/sup&gt;&lt;span&gt;. The forest floor inorganic N pool was ≈ 2 kg ha&lt;/span&gt;&lt;sup&gt;-1&lt;/sup&gt;&lt;span&gt;, eight times larger than monthly precipitation N input. The inorganic N pool size peaked in spring and early summer. Ninety percent of the forest floor inorganic N pool was made up of NH&lt;/span&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;-N. Forest floor inorganic N pools generally increased with temperature. Net N mineralization was 15 kg ha&lt;/span&gt;&lt;sup&gt;-1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;yr&lt;/span&gt;&lt;sup&gt;-1&lt;/sup&gt;&lt;span&gt;, and monthly rates peaked in early summer. During winter, the mean monthly net N mineralization rate was twice the peak snowpack N content. Streamwater NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;concentration peaked in winter, and inorganic N output peaked in late fall. Beneath the dominant boreal forest species, net N mineralization rates were positively correlated (&lt;/span&gt;&lt;i&gt;P&lt;/i&gt;&lt;span&gt;&amp;nbsp;&amp;lt; 0.05) with streamwater NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;concentrations. Forest floor NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;pools beneath alder [&lt;/span&gt;&lt;i&gt;Alnus rugosa&lt;/i&gt;&lt;span&gt;&amp;nbsp;(Du Roi) Spreng] were positively correlated (&lt;/span&gt;&lt;i&gt;P&lt;/i&gt;&lt;span&gt;&amp;nbsp;&amp;lt; 0.01) to streamwater NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;output. At the watershed mouth, streamwater NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;concentrations were positively correlated (&lt;/span&gt;&lt;i&gt;P&lt;/i&gt;&lt;span&gt;&amp;nbsp;&amp;lt; 0.05) with precipitation NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;input and precipitation amount. The relatively small snowpack N content and seasonal precipitation N input compared to forest floor inorganic N pools and net N mineralization rates, the strong ecosystem retention of precipitation N inputs, and the seasonal streamwater NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;concentration and output pattern all indicated that little streamwater NO&lt;/span&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;came directly from precipitation or snowmelt.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.2136/sssaj1999.03615995006300020018x</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Wiley</dc:publisher>
  <dc:title>Seasonal relationships between precipitation, forest floor, and streamwater nitrogen, Isle Royale, Michigan</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>