Katy O’Donnell
Bryan D. Downing
Jon R. Burau
Brian A. Bergamaschi
Tamara E. C. Kraus
2017
<p><span>We used paired continuous nitrate ( </span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0001.png?v=1&s=22c5715a6e2fdcc31e2624a9c77f43f8d1e6bc0d" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0001.png?v=1&s=22c5715a6e2fdcc31e2624a9c77f43f8d1e6bc0d"></span></span><span>) measurements along a tidally affected river receiving wastewater discharge rich in ammonium (<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0002.png?v=1&s=6e850ad756ee9fc2b59f2c62cce5080ba359fec2" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0002.png?v=1&s=6e850ad756ee9fc2b59f2c62cce5080ba359fec2"></span></span><span>) to quantify rates of change in<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0003.png?v=1&s=edd1801396530467a9c1886f4d85f881efc4aa35" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0003.png?v=1&s=edd1801396530467a9c1886f4d85f881efc4aa35"></span></span><span><span> </span>concentration (<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0004.png?v=1&s=4ef983b0aa6ea4bcfbb1fd623360b8ef2f78f55e" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0004.png?v=1&s=4ef983b0aa6ea4bcfbb1fd623360b8ef2f78f55e"></span></span><span>) and estimate nitrification rates.<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0005.png?v=1&s=af1ee755b266e46e4993cc3089e9949d0681738d" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0005.png?v=1&s=af1ee755b266e46e4993cc3089e9949d0681738d"></span></span><span><span> </span>sensors were deployed 30 km apart in the Sacramento River, California (USA), with the upstream station located immediately above the regional wastewater treatment plant (WWTP). We used a travel time model to track water transit between the stations and estimated<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0006.png?v=1&s=ac569aa42fa9e978ae109f1f21fac0992034f6f5" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0006.png?v=1&s=ac569aa42fa9e978ae109f1f21fac0992034f6f5"></span></span><span><span> </span>every 15 min (October 2013 to September 2014). Changes in<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0007.png?v=1&s=09413b94c0dbbc1520403721dc5cb821ea2bdfd8" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0007.png?v=1&s=09413b94c0dbbc1520403721dc5cb821ea2bdfd8"></span></span><span>concentration were strongly related to water temperature. In the presence of wastewater,<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0008.png?v=1&s=067241a15e12389f8f6612a921f71fef905edb86" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0008.png?v=1&s=067241a15e12389f8f6612a921f71fef905edb86"></span></span><span>was generally positive, ranging from about 7 µ</span><i>M</i><span> d</span><sup>−1</sup><span><span> </span>in the summer to near zero in the winter. Numerous periods when the WWTP halted discharge allowed the<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0009.png?v=1&s=5e476b3d5f1ca100f0b42c10db9f921fe2c56b52" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0009.png?v=1&s=5e476b3d5f1ca100f0b42c10db9f921fe2c56b52"></span></span><span><span> </span>to be estimated under no-effluent conditions and revealed that in the absence of effluent, net gains in<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0010.png?v=1&s=000d3d020109a713ceae82ba1a91c88a1a0e2b7c" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0010.png?v=1&s=000d3d020109a713ceae82ba1a91c88a1a0e2b7c"></span></span><span><span> </span>were substantially lower but still positive in the summer and negative (net sink) in the winter. Nitrification rates of effluent-derived NH</span><sub>4</sub><span><span> </span>(<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0011.png?v=1&s=a12b09a6bb2367ef84836d9f309f09415817e6a8" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0011.png?v=1&s=a12b09a6bb2367ef84836d9f309f09415817e6a8"></span></span><span>) were estimated from the difference between<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0012.png?v=1&s=029e4f1a23b5b28155d9d510cc025f0aa221847f" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0012.png?v=1&s=029e4f1a23b5b28155d9d510cc025f0aa221847f"></span></span><span><span> </span>measured in the presence versus absence of effluent and ranged from 1.5 to 3.4 µ</span><i>M</i><span> d</span><sup>−1</sup><span>, which is within literature values but tenfold greater than recently reported for this region.<span> </span></span><span class="math-equation-construct" data-equation-construct="true"><span class="math-equation-image" data-equation-image="true"><img class="inlineGraphic" src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0013.png?v=1&s=10ca0a9987aff8303b86e43a344b3bdc16ffe889" alt="math formula" data-mce-src="http://onlinelibrary.wiley.com/store/10.1002/2017WR020670/asset/equation/wrcr22895-math-0013.png?v=1&s=10ca0a9987aff8303b86e43a344b3bdc16ffe889"></span></span><span><span> </span>was generally lower in winter (∼2 µ</span><i>M</i><span> d</span><sup>−1</sup><span>) than summer (∼3 µ</span><i>M</i><span> d</span><sup>−1</sup><span>). This in situ, high frequency approach provides advantages over traditional discrete sampling, incubation, and tracer methods and allows measurements to be made over broad areas for extended periods of time. Incorporating this approach into environmental monitoring programs can facilitate our ability to protect and manage aquatic systems.</span></p>
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10.1002/2017WR020670
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AGU
Using paired in situ high frequency nitrate measurements to better understand controls on nitrate concentrations and estimate nitrification rates in a wastewater-impacted river
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