The authors acknowledge the Water Quality Analysis Laboratory at the University of New Hampshire for assistance with sample analysis. The authors also thank two anonymous reviewers whose comments have helped to improve the manuscript. This work is funded by the National Science Foundation (DEB-1556603). Partial funding was also provided by the EPSCoR Ecosystems and Society Project (NSF EPS-1101245), New Hampshire Agricultural Experiment Station (Scientific Contribution #2662, USDA National Institute of Food and Agriculture (McIntire-Stennis) Project (1006760), the University of New Hampshire Graduate School, and the New Hampshire Water Resources Research Center.

1.识别和表征的理想的实验流达到<ol><li>确保实验流达到足够长，以促进溶质11和足够长的时间可以发生生物吸收的完全混合。河段长度可流和实验而异。在小一阶水源流，达到的长度可以从20〜150米（或更长，如果系统需要它），这取决于放电和流的其他物理特性而变化。 <ol><li>从实验达到排除大池，因为它们阻止溶质，最小流部分，并且该稀释加入溶液支流的下游移动。低排放的时间可能需要缩短到达长度，同时更高的放电可能需要更长的范围。 </li><li>在实验流达到一浅滩上方的顶部确定的位置，以促进加入的溶质的混合。这将是除部位。在实验流的底部到达，查明流被收缩和代表性的总流量的约90％（ 图1）的位置。这将是样品收集点。 </li></ol></li></ol><img alt="图1" src="/files/ftp_upload/54704/54704fig1.jpg" /> 图1:下游采样点为例理想的采样点是大部分流量是收缩，无流道和底栖生物的扰动很方便。在这里，木材碎片堕落一块创造了一个小的一级水源流这个采样点。 <a href="https://www.jove.com/files/ftp_upload/54704/54704fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <ol start="2"><li>获得感兴趣之前实验溶质的流量测量和背景营养物浓度，以计算所需的MANIP溶质的质量ulations。请参阅步骤2.2.1计算。 <ol><li>得到背景浓度数据进行操纵的目标溶质（ 例如 NO 3 - ）和氯（Cl -的），它经常被用作示踪剂。使用保守示踪剂在这些实验中的情况下，跟踪于电导率的变化，这表明营养脉冲在采样到站并且其中脉冲穿过速率。电导率或电导率，是在保守的示踪剂浓度的原地变化的替代品。 </li><li>通过收集辅助数据，如覆盖宽度和深度，温度，pH和溶解氧表征实验达到的生理化学性质。 <ol><li>执行无法与使用环境探测器（ 例如宽度和深度），一天中的之前或以尽量减少任何底栖ö实验后立即进行的测量流道R内的化学紊乱。划分在等距横断面实验距离（ 例如，每10米），其中宽度和至少3个深度测量可评估（ 例如 ，右行，深谷底线和左行）。这些数据是有价值的连接流到生物地球化学测量的物理性质，并且如果研究者也有兴趣在计算养分摄取动力学和参数6。 </li></ol></li></ol></li></ol> 2.准备实验<ol><li>确定使用下面的概述的方程操纵所需溶质的质量（kg）。 注意:以下示例适用于基于硝酸盐实验NO 3 -在硝酸钠的形式（纳米3），并假定3倍的上述背景有针对性的增加（公式是基于这些基尔帕特里克和科布12）。在本实施例以下假设已与水库面面观背景条件:排放量= 10升/秒; [CL] = 10毫克/升; [NO 3 - ] = 50微克N / L。由于实验中的变化，调整所需的输入数据。 <ol><li>计算目标增加（等式1）: 目标[NO 3 -微克N / L]增加=预计背景[NO 3 -微克N / L] *有针对性的增加 150微克N / L = 50微克N / L * 3 </li><li>计算总原子质量通量（式2）: 总原子质量通量（NO 3 -微克N）= 30分钟* 60秒* Q（L /秒）*针对性[NO 3 -微克N / L]增加 其中，30分钟溶质峰12的假设持续时间和Q是放电 2 700 000微克N = 30分钟* 60秒* 10升/秒* 150微克N / L </li><li>计算总分子质量通量（等式3）: 总分子质量通量（NO 3 -微克N）=总原子质量通量（NO 3 -微克N）/原子质量（14）*分子，我们飞行（85） 其中，原子质量指N和分子量指的NaNO 3。 16,392,857.14微克N = 270万微克N /（14 * 85） </li><li>计算质量增加（方程4）: 大众加（G）=总分子量通量（NO 3 -微克N）1 / 1000000-克/微克 16.39克硝酸钠 = 16,392,857.14微克N /百万克/微克 注意:按照上述计算任何其他溶质，包括保守示踪剂（ 如氯化钠）。确保调整原子和分子群众利益的溶质。 </li></ol></li><li>准备前一天现场实验的所有溶质。掂量出足够的溶质，以提高这两个生物示踪剂和示踪剂的环境浓度的三倍（或期望的量）以上的背景。重要的是，加入的溶质的量将导致上述背景浓度的可测量变化足以创建AWIDE动态范围，增加营养浓度。 <ol><li>称重使用分析天平溶质，并随后在适当的标签清洁酸洗高密度聚乙烯瓶储存。生物示踪剂的实例包括:NO 3 - :硝酸钠（纳米3）; NH + 4:氯化铵（NH 4 Cl）的; PO 4 -3:磷酸钾（K 2 HPO 4）。然而，生物示踪剂的选择将是被要求的生物地球化学问题的功能。保守示踪剂选项包括氯化钠（NaCl）和溴化钠（溴化钠）。 </li></ol></li><li>收集剩余材料:现场的书，标签胶带和钢笔，现场卷尺，冷却器，电导率仪，〜20升桶和大型搅拌棒（ 如啤酒桨，螺纹钢，大棒），约50清洁和酸洗125毫升高-density聚乙烯瓶。标签125 ml瓶装＃1-50。 注释:LESS大于50个样品，可采取每次实验和背景样本包括在50总瓶。 </li><li>可选:根据现场人员的数量，进行现场采样滤波（见＃5）。如果选择此选项，带来50清洁，预标记和酸洗60毫升高密度聚乙烯瓶进入该领域。标签上的60毫升瓶＃1-50匹配125 ml收集瓶。 </li></ol> 3.设置的天<ol><li>部署在收集现场实地电导率仪。将上游的仪器，其中样品将被采取因此样本采集不仪器读数干扰（约0.5〜1.0米）。仪器会保持在原位整个实验。字段电导率仪是最好的，因为它提供了实时的电导率读数，这是必需的，以确定在采样率（参见步骤5.2）和过滤和分析顺序（步骤5.3和6.1）。 </li><li>收集125毫升背景SAMPLES在在添加位点，一式三份，并在之前加入该溶液的实验触及的收集站。这些数据将被用于验证环境浓度日，并确定在沿流达到溶质浓度变化。这些数据也有价值连接环境流化学: -对感兴趣的生物地球化学测量（ 如 DOC NO 3比13）。 </li><li>记录收集的背景样本的时间和电导率。 </li><li>记录数据流的背景电导另外的解决方案之前。 </li></ol> 4.添加溶质<ol><li>倒入所有试剂（16.39克硝酸钠3号和第1483克氯化钠），成为一个大的容器（ 如 20升桶），并补充足够的溪水完全溶解溶质。冲洗试剂容器用三次附加流水，倒到冲洗液容器。跟踪的水量增加。 <ol><li>例如，使用500毫升一瓶河水倒入容器中。搅拌溶液，直到所有的试剂已经被完全溶解。 </li></ol></li><li>收集60毫升等分加液。远离所有其他样品这种高度浓缩的样品中分离（ 如拉链锁袋），以尽量减少交叉污染。这些样品是重要的，如果计算养分摄取动力学6是该研究项目的另外的目标，因为这些样品可被用于确定加入溶质的精确质量。 </li><li>倒入溶液倒入另外的网站。浇解决方案顺利和快速的动作，尽量减少出行滞后时间和飞溅能够降低加试剂的量做到这一点。冲洗除了保证所有试剂已被添加到流后，立即在容器和搅拌棒的流中三次。 <ol><li>记录溶液中加入时间:小时:分:秒。 </li><li>记录示踪剂增加群众（ 如 硝酸钠和氯化钠）。 </li><li>该解决方案已经被添加后，不打扰流。确保沿流的所有旅行对银行发生，以确保流底栖生物和溶液本身不受到干扰。 </li></ol></li></ol> 5.现场取样<ol><li>按升序排列顺序采样瓶，等待解决到达采样位置。旅行时间将放电的功能，并达到长度，并且可以提前确定（一天之前）或者用NaCl仅注射或若丹明染料（可用于建立行程时间14）。 注意:如果在DON为主题的项目时，应避免使用罗丹明，因为它是一种DON，因此将改变环境DON池，如果在研究中达成任何遗迹。 </li></ol><img alt="图2" src="/files/ftp_upload/54704/54704fig2.jpg" /> 图2:溶质穿透曲线的实施例示意图（BTC）。一个BTC表示随时间的溶质浓度的变化，并且可以用来解释示踪剂的转运和生物地球化学循环流中。抓斗采样应在整个BTC可以采取，让平等代表权的上升和BTC降四肢都的频率。 <a href="https://www.jove.com/files/ftp_upload/54704/54704fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <ol start="2"><li>样品采集 注:涵盖范围广泛的样本采集的目的，就是通过曲线（BTC）（ 图2），以充分代表沿断裂的肢体上升和下降的溶质浓度的变化。 <ol><li>在该溶液（通过增加导电率检测）的到来，通过保持125毫升瓶入水在取样点处的主流收集在整个BTC125毫升瓶样品。快LY冲洗瓶子用溪水和丢弃冲洗下游再取样品。帽样品并放入凉。 </li><li>记录时间（小时:分钟:秒）和电导率沿BTC取入字段书（ 表1）每个样品的。 </li><li>收集基于时间（ 例如 1分钟的间隔），或者基于所述速率电导率的变化的样品。例如，如果电导率变化很快，采样每30-60秒直到在导电性缓慢的变化，在哪些时间样本可采取每次5-10分钟。对于基于导电率的时间间隔，取样品每15-30单位根据是在电导率变化率。 </li><li>样品电导率，直到返回到后台或背景条件5μS/ cm的范围内。样品收集的时间间隔可在实验过程中，只要BTC在抓取样品中公表示进行调整。 </li></ol></li></ol><table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within页="总是"&gt; <tbody><tr><td> 瓶子 ＃ </td><td> 电导率 </td><td> 时间 </td><td> 笔记 </td></tr><tr><td> 1 </td><td></td><td>小时:分:秒</td><td> 例如，背景（下游） </td></tr><tr><td> 2 </td><td></td><td></td><td> 例如，背景（下游） </td></tr><tr><td> 3 </td><td></td><td></td><td></td></tr><tr><td> 4 </td><td></td><td></td><td></td></tr><tr><td>五</td><td></td><td></td><td> 如在高峰电导样本</td></tr><tr><td> 。 </td><td></td><td></td><td></td></tr><tr><td> 。 </td><td></td><td></td><td></td></tr><tr><td> 。 </td><td></td><td></td><td></td></tr><tr><td>最高瓶＃ </td><td></td><td></td><td></td></tr></tbody></table> 表1PField书:示例Page从实验室簿和所需信息<ol start="3"><li>样品过滤 注:样品的过滤可以在现场或在返回到实验室进行。 <ol><li>从上升肢体筛选样品中上升的电导率，直至电导率峰值顺序。等待实验结束了，过滤器的样品从电导率的升序肢体下降（ 即开始与最后的采样，向峰值比电导率向后工作）。 注:样品的这种顺序减少样品间的交叉污染，并允许对于相同的过滤器，注射器，和过滤器保持器，只要被用作过滤器时，注射器和过滤器保持器在每个样品之​​间被适当冲洗（见步骤5.3.2- 5.3.4）。 </li><li>从60毫升注射器，然后关闭止水栓取出活塞。倒入约10毫升的样品到注射器中，并返回柱塞注射器。摇动注射器使样品冲洗注射器的内部的壁。附注射器，过滤架和开放式止水栓。通过推过滤架样品和丢弃冲洗。 </li><li>拆下柱塞和关闭止水栓。倒入约30毫升的样品到注射器中，并返回柱塞注射器。开放式股票型公鸡排出通过〜10毫升过滤架和进60毫升取样瓶。盖上瓶子，用滤液漩涡并丢弃。重复此步骤，共3漂洗。这将确保任何杂质已从上的60毫升样品瓶中取出，该壁涂有样本。 </li><li>拆下柱塞和关闭止水栓。倒〜60 mL样品到注射器中，并返回柱塞注射器。通过过滤器保持器并进入上的60毫升样品瓶推样品。灌装瓶到肩膀，以防止结冰时瓶子开裂。盖瓶并放入凉。 </li><li>重复步骤5.3.2-5.3.4所有剩余的样品。改变上升和下降的肢体样本，以尽量减少污染的过滤器。 </l我&gt; <li>运输样本回在同一天，在冰上的实验室。 </li></ol></li></ol> 6.准备实验室分析<ol><li>如果样品的过滤是在实验室发生，按照协议，如第5.3.1所述。从升，并在提高电导率的顺序降的BTC四肢两个滤波器采样。改变上升肢和下降沿肢样本之间的过滤器。 </li><li>在-20℃下直到分析冷冻过滤的样品。 </li><li>确保分析设施配备，以处理高浓度的样品。 注意:有些实验室不具备运行高度浓缩的样品，因此，应注意。合并准备的标准，即捕获预计溶质浓度较高端。高浓度的标准将有助于确保捕获操纵溶质浓度的预期范围内的标准曲线。 </li><li>样本分析从低到所有的分析仪器高导电性。从低订购样品到高电导率高盐/营养样防止低盐/营养样品的污染。这意味着从四肢的上升和下降的样品将参照序列进行混合。 <ol><li>分析总溶解的有机碳，总溶解氮，硝酸盐和铵的样品，虽然溶质分析的确切组合将是所研究的问题的一个功能（参见Wymore 等人 10为例）。 </li></ol></li></ol> 7.数据分析<ol><li>分析使用简单线性回归的数据。独立变量是所添加的营养物的浓度和因变量是DOM浓度无论是作为DOC或DON。图上的每一个点代表从突破曲线和样品的养分和DOC / DON浓度中品尝样品。 </li></ol>

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<li>Kilpatrick, F. A., Cobb, E. D. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aKilpatrick%2C+FA+%22Measurement+of+discharge+using+tracers%3A+U.S+Geological+Survey+Techniques+of+Water-Resources+Investigations%22">Measurement of discharge using tracers: U.S Geological Survey Techniques of Water-Resources Investigations</a>. , 
 <a target="_blank" href="http://pubs.usgs.gov/twri/twri3-a16">http://pubs.usgs.gov/twri/twri3-a16</a> (1985).</li>
<li>Rodríguez-Cardona, B., Wymore, A. S., McDowell, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((DOC%3A+NO3-+and+NO3-+uptake+in+forested+headwater+streams%5BTitle%5D)+AND+%22J+Geophys+Res+-+Biogeo%22%5BJournal%5D)">DOC: NO3- and NO3- uptake in forested headwater streams.</a> J Geophys Res - Biogeo. 121, (2016).</li>
<li>Kilpatrick, F. A., Wilson, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Book+3+Chapter+A9%2C+Measurement+of+time+of+travel+in+streams+by+dye+tracing%5BTitle%5D)+AND+%22Techniques+of+Water-Resources+Investigations+of+the+United+States+Geological+Survey%22%5BJournal%5D)">Book 3 Chapter A9, Measurement of time of travel in streams by dye tracing.</a> Techniques of Water-Resources Investigations of the United States Geological Survey. , (1989).</li>
<li>Lutz, B. D., Bernhardt, E. S., Roberts, B. J., Mulholland, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Examining+the+coupling+of+carbon+and+nitrogen+cycles+in+Appalachian+streams%3A+the+role+of+dissolved+organic+nitrogen%5BTitle%5D)+AND+%22Ecology%22%5BJournal%5D)">Examining the coupling of carbon and nitrogen cycles in Appalachian streams: the role of dissolved organic nitrogen.</a> Ecology. 92 (3), 720-732 (2011).</li>
<li>Michalzik, B., Matzner, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Dynamics+of+dissolved+organic+nitrogen+and+carbon+in+a+Central+European+Norway+spruce+ecosystem%5BTitle%5D)+AND+%22Eur+J+Soil+Sci%22%5BJournal%5D)">Dynamics of dissolved organic nitrogen and carbon in a Central European Norway spruce ecosystem.</a> Eur J Soil Sci. 50 (4), 579-590 (1990).</li>
<li>Solinger, S., Kalbitz, K., Matzner, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Controls+on+the+dynamics+of+dissolved+organic+carbon+and+nitrogen+in+a+Central+European+deciduous+forest%5BTitle%5D)+AND+%22Biogeochemistry%22%5BJournal%5D)">Controls on the dynamics of dissolved organic carbon and nitrogen in a Central European deciduous forest.</a> Biogeochemistry. 55 (3), 327-349 (2001).</li>
<li>Kaushal, S. S., Lewis, W. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Patterns+in+chemical+fractionation+of+organic+nitrogen+in+Rocky+Mountain+streams%5BTitle%5D)+AND+%22Ecosystems%22%5BJournal%5D)">Patterns in chemical fractionation of organic nitrogen in Rocky Mountain streams.</a> Ecosystems. 6 (5), 483-492 (2003).</li>
<li>Kaushal, S. S., Lewis, W. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Fate+and+transport+of+organic+nitrogen+in+minimally+disturbed+montane+streams+of+Colorado%2C+USA%5BTitle%5D)+AND+%22Biogeochemistry%22%5BJournal%5D)">Fate and transport of organic nitrogen in minimally disturbed montane streams of Colorado, USA.</a> Biogeochemistry. 74 (3), 303-321 (2005).</li>
</ol>

The authors have nothing to disclose.

营养脉冲方法的目的，如这里提出，是表征和量化环境流水DOM的高度多样化池的两端一个附加的无机养分的动态范围的响应。如果添加溶质充分提高了反应溶质的浓度，大的推理空间可以创建理解DOM的生物地球化学循环如何链接到营养浓度。这种营养脉冲的方法是理想的，因为它涉及无用高原式加成相关联的机械的（ 例如蠕动泵），并且不涉及昂贵同位素技术。这些操作是容易复制和多种实验可以在一天内进行。然而，我们建议，如果在单个流到达在同一天进行复制实验，即增加由几个小时分离，以允许残余溶质充分冲洗。 在日我们ESE生态系统的操作能够测量响应于添加营养素中DOM的环境池的浓度变化。然而，用这种方法是不可能评论在其上的DOM池实际上减少或增加超出DON和DOC的浓度变化的部件。我们不能辨别是否是DON的例如某种形式，即优先与加成NO 3的消耗- 。变化可能是由于改变了足以改变整个浓度高度丰富，形式提供的DON（ 如氨基酸）。然而，这个领域为基础的方法可以容易地用高分辨率分析化学方法配对（ 如荧光光谱，傅立叶变换离子回旋共振质谱法），以确定哪些组件或分子的类被直接响应实验操作。 除了DOM车米斯特里，其他生物和环境因素可能影响的DOM的添加营养素的响应。要理解这种多因素的相互作用等领域的数据可以被收集，审查其他重要变量。在DON响应硝态氮（ 图3A-3F）的方向随时间的变化可能反映了自养与异养为主的进程。例如，在图3A中的正相关关系，可能反映了自养生物的活性。它很可能是在五月仍有足够光合有效辐射到达流（之前河岸郁闭）和观察到的图案反映了这些生物从DON移为NO 3 -作为其氮的来源，这导致增加DON浓度。后来在本赛季（ 如图3E）观察到的负相关关系，可能代表谁是挖掘Ð异养微生物的活性ON其能量含量。为了检验这一类型基于生物的假设的，今后的研究可以纳入的自养站立库存并发测量，微生物活性的水平或酶的浓度，例如。在其他环境梯度，包括溶解氧和温度检查DOM的硝酸盐相互作用，可能有助于阐明在推动DOM和硝酸盐的生物地球化学耦合等理化参数的作用。 低NO 3的选择-流是这些实验的成功至关重要，并保留衡量唐池变化的能力。研究探讨NO 3之间的相互作用-拼成的TDN池的小于50％ -例如和DON，其中NO 3应该发生在流。经由减法测量的DON精度大大降低当NO 3 -贡献的太大的一小部分TDN池由于存在围绕DON测量从TDN，NO 3的分析结果的乘法误差项-和NH 4 +。这样的子最佳条件可导致负DON的浓度。如河口-因此这种技术可以在很大程度上受到NO 3障系统的限制。 虽然较大的溪流和河流呈现自己的一系列挑战，这种方法可能适用于高阶系统。例如，坦克等 5 第 7阶上斯内克河在怀俄明州进行营养脉冲实验研究溶解无机N的吸收动力学有很多方法可以在任一湖泊，土壤或地下水进行类似的实验。然而，这样的实验，由于与的方式，小型系统暴露在养分浓度的梯度或含有试点单位所面临的挑战是很难迈兹中断和试验中的人为。这是使用流生态系统为这些类型的操纵实验的优点之一。然而，对其他生态系统类似的方法，特别是系统过度氮负荷（ 如河口）受损，发展可能有重要的管理意义，因为我们开始懂得在不同形式的n个驱动富营养化和有毒赤潮在沿海水域的途径。

溶解有机物质（DOM）提供了一个重要的能量和营养源的淡水的生态系统和被定义为通过0.7微米的过滤器通过有机物。在水生生态系统，DOM也能影响光衰减和金属络合。 DOM是具有各种官能团的有机化合物，以及必需的营养物质，如氮（N）和磷（P）的高度多样化和不均匀混合物。而"DOM"介绍，包括其C，N和P分量整个池，其浓度作为溶解有机碳（DOC）测定。在DOM池固有的复杂分子然而，造成其研究的挑战。例如，有测量由有机营养物如溶于有机氮（DON）和可溶性有机磷（DOP）的总的DOM池的分数没有直接的方法。相反，有机营养的浓度必须通过差来确定（ <em&gt;如:[DON] = [总溶解氮] - [无机氮]）。 添加一个现实的DOM修正案到流是困难的，因为环境的DOM池的多样性。以前的研究已经加入单一碳源（ 如葡萄糖，尿素1） 或如落叶层渗滤液2特定源来操纵在外地的浓度。不过，这些来源不是特别有代表性的环境DOM池。试图缩小或集中用于随后的实验环境的DOM也造成了困难，包括某些馏分（ 如高度不稳定分量）的处理过程中的损失。其结果是，它是很难理解的周围的DOM池对照，因为我们目前不具备任何方法直接操作环境的DOM池。然而，由于DOM的生物地球化学被链接到在环境中常见的营养物质（ 例如尼特率[NO 3 - 3），我们可以添加其他溶质流生态系统和测量DOM池这些操作的响应。通过检查DOM池如何响应广泛的实验实行营养浓度，我们希望能够更加深入地了解DOM如何应对波动的环境条件。 在流生物地球化学常用的一种方法是在营养物添加方法。营养除了实验历来被用来理解吸收动力学或添加溶质4,5,6,7的命运。营养增补可以是对小时6天标尺4，或长期操作过的多个年8过程的短期。营养增补还可以包括同位素标记的营养素（ 例如 ，15 N-NO 3 - ）通过生物地球化学反应来跟踪添加营养素。然而，基于同位素研究往往EXPEnsive并要求多个底栖车厢，其中同位素标记的营养素可以保留的具有挑战性的分析（ 如消化）。最近的实验揭示了短期脉冲营养素的效用阐明非加和环境溶质，如DOM 9,10对照，揭示由检查原位生物地球化学反应实时的新方法。在这里，我们描述和证明密钥的方法步骤，以了解C，N及具体的控制的耦合生物地球化学的高度多样化的DOM池的目标进行短期养分脉冲。此容易再现方法包括添加营养脉冲的实验流达到并测量在这两个操纵溶质和感兴趣的响应变量（ 如 DOC，DON，DOP）的浓度变化。 通过原位直接操纵营养物浓度，我们能够间接改变DOM游泳池和检查跨越营养浓度10的动态范围DOM浓度如何变化的。

<table><tbody><tr><td>Sodium Nitrate</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Sodium Chloride</td><td>Any</td><td>Any</td><td>Store purchased table salt can be used as well, however, it does contain trace levels of impurities</td></tr><tr><td>Whatman GFF glass-fiber filters</td><td>Any</td><td>Any</td><td></td></tr><tr><td>BD Filtering Syringe</td><td>Any</td><td>Any</td><td></td></tr><tr><td>EMD Millipore Swinnex Filter Holders</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Syringe stop-cock</td><td>Any</td><td>Any</td><td></td></tr><tr><td>YSI Multi-parameter probe</td><td>Yellow Springs International</td><td>556-01</td><td></td></tr><tr><td>Wide mouth HDPE 125 ml bottles</td><td>Any</td><td>Any</td><td></td></tr><tr><td>60 ml HDPE bottles</td><td>Any</td><td>Any</td><td></td></tr><tr><td>20 L bucket</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Field measuring tape</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Lab labeling tape</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Stir stick</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Cooler</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Sharpie pen</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Field notebook</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Tweezers</td><td>Any</td><td>Any</td><td></td></tr><tr><td>Zip-lock bags</td><td>Any</td><td>Any</td><td></td></tr></tbody></table>

understanding dissolved organic matter biogeochemistry through in situ nutrient manipulations in stream ecosystems

Dissolved organic matter (DOM) is a highly diverse mixture of molecules providing one of the largest sources of energy and nutrients to stream ecosystems. Yet the in situ study of DOM is difficult as the molecular complexity of the DOM pool cannot be easily reproduced for experimental purposes. Nutrient additions to streams however, have been shown to repeatedly alter the in situ and ambient DOM pool. Here we demonstrate an easily replicable field-based method for manipulating the ambient pool of DOM at the ecosystem scale. During nutrient pulse experiments changes in the concentration of both dissolved organic carbon and dissolved organic nitrogen can be examined across a wide-range of nutrient concentrations. This method allows researchers to examine the controls on the DOM pool and make inferences regarding the role and function that certain fractions of the DOM pool play within ecosystems. We advocate the use of this method as a technique to help develop a deeper understanding of DOM biogeochemistry and how it interacts with nutrients. With further development this method may help elucidate the dynamics of DOM in other ecosystems.

<img alt="图3" src="/files/ftp_upload/54704/54704fig3.jpg" /> 图 3: 硝酸结果示例（NO 3 - ）溶解有机氮（DON）为应变量附加的分析是线性回归。星号代表在α= 0.05的统计学意义。注意NO 3的动态范围-即用营养脉冲方法来实现的浓度。不同的面板代表整个月和站点不同的实验。站点缩写指三个实验的流10。正相关被解释为反映DON的作为营养源的作用，而负相关被解释为反映DON的作为能量来源的作用。这造成了不显著关系实验解释为反映无响应DON池（ 即高度的recAlcitrant）或基于营养流程和基于能量的过程是关闭设定。请参阅Wymore 等 10结果进一步讨论。 <a href="https://www.jove.com/files/ftp_upload/54704/54704fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54704/54704fig4.jpg" /> 图 4: 硝酸结果示例（NO 3 - ）与溶解有机碳（DOC）作为响应变量附加的分析是线性回归。星号代表在α= 0.05的统计学意义。不同的面板代表整个月和站点不同的实验。站点缩写指三个实验的流10。在整个多数实验观察到周围DOC池中没有显著变化。阴性结果可以揭示一个布特加上生物地球化学过程。请参阅Wymore 等 10结果进一步讨论。 <a href="https://www.jove.com/files/ftp_upload/54704/54704fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 通过对 NO 3 就地操纵的直接- ，我们可以间接地改变DOM池提供洞察与使用环境的DOM池的生物地球化学控制浓度图3显示了结果从研究，审查NO 3之间的相互作用-和DON 10。虽然在整个实验变化（由于在背景溶质浓度变化）的溶质增长的确切大小NO 3的足够大的梯度-分别通过营养物添加的方法创建。从这组实验中，在三个流域新Hampsh愤怒，美国，我们能够做出DON的水源流的生态作用的推论。作为有机营​​养物，DON可用作任一能量源（碳）或作为氮源。在这些低NO 3 -流，我们解释在DON浓度的增加，以反映其利用作为营养源。通过提供微生物群落与N的高度可用的形式，NO 3 - ，社区从DON转移到这个新形式提供。此以前已经被称为DON释放假说15。与此相反，我们在这些硝酸盐的操作中观察到的负相关被解释为反映DON利用作为能源。此异过程已被称为被动-碳车辆假说1,15。 DON的整个生长季节的高度变化的响应表明，在DON如何应对补充营养素季节性强。这些数据提供了一些关于该DON服务流的生态系统中的生态作用第一场为基础的实验结果。 从这些生态系统操作阴性结果也与关于对生物地球化学过程控制透露。例如， 图4示出了在环境DOC池加入NO 3没有可测量响应- 。这表明，DOC的环境池是非常顽固的（ 即不是生物反应）。当营养脉冲重复在生长季节，例如执行，我们可以对DOM池的不同部分是由水生微生物群落所使用的方式和时间推论和结论。通过这些操纵生态系统规模实验中，我们能够在整个加入养分的动态范围辨别DOM的池的某些馏分之间的相互作用。这些结果特别表明，N-二富馏分并独立于DOM池循环-C丰富的部分，可能有自己独特的集生态和生物地球化学控制16,17。通过使用这种营养素添加方法，我们已经能够提供操控基于字段的数据，提供了强有力的证据，并已以前只有实验室孵化18,19被观察到DON不稳模式的支持。

Watch this Scientific Journal Video about Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems at JoVE.com

通过溪流生态系统中的原位养分操纵了解溶解有机物的生物地球化学|环境 |视频

Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

溶解有机物提供能量和营养流生态系统的一个重要来源。在这里，我们展示了一个基于现场的方式，通过很容易复制的营养脉冲操纵原位溶解有机物环境池。

了解溶解有机物生物地球化学通过<em&gt;原位</em&gt;在河流生态系统营养手法

Dissolved organic matter (DOM) is a highly diverse mixture of molecules providing one of the largest sources of energy and nutrients to stream ecosystems. ...

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Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

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10.3K 次观看.  University of New Hampshire. 溶解有机物提供能量和营养流生态系统的一个重要来源。在这里，我们展示了一个基于现场的方式，通过很容易复制的营养脉冲操纵原位溶解有机物环境池。 

视频: Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

Tracing rare stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes and soil organic matter formation to small-scale stable-isotope biomarker probing. Coupling multiple stable isotopes such as 13C with 15N, 18O or&#160;2H has the potential to reveal even more information about complex stoichiometric relationships during biogeochemical transformations. Isotope labeled plant material has been used in various studies of litter decomposition and soil organic matter formation1-4. From these and other studies, however, it has become apparent that structural components of plant material behave differently than metabolic components (i.e. leachable low molecular weight compounds) in terms of microbial utilization and long-term carbon storage5-7. The ability to study structural and metabolic components separately provides a powerful new tool for advancing the forefront of ecosystem biogeochemical studies. Here we describe a method for producing 13C and 15N labeled plant material that is either uniformly labeled throughout the plant or differentially labeled in structural and metabolic plant components.
Here, we present the construction and operation of a continuous 13C and 15N labeling chamber that can be modified to meet various research needs. Uniformly labeled plant material is produced by continuous labeling from seedling to harvest, while differential labeling is achieved by removing the growing plants from the chamber weeks prior to harvest. Representative results from growing Andropogon gerardii Kaw demonstrate the system&#39;s ability to efficiently label plant material at the targeted levels. Through this method we have produced plant material with a 4.4 atom%13C and 6.7 atom%15N uniform plant label, or material that is differentially labeled by up to 1.29 atom%13C and 0.56 atom%15N in its metabolic and structural components (hot water extractable and hot water residual components, respectively). Challenges lie in maintaining proper temperature, humidity, CO2 concentration,&#160;and light levels in an airtight 13C-CO2 atmosphere for successful plant production. This chamber description represents a useful research tool to effectively produce uniformly or differentially multi-isotope labeled plant material for use in experiments on ecosystem biogeochemical cycling.

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

This method explains how to build and operate a continuous 13C and 15N isotope labeling chamber for uniform or differential plant tissue labeling. Representative results from metabolic and structural labeling of Andropogon gerardii are discussed.

设计一个连续和操作<sup&gt; 13</sup&gt; C和<sup&gt; 15</sup&gt;Ñ贴标商会统一或差分，代谢和结构，植物同位素标记

Tracing rare stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes ...

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环境科学

Unraveling the Unseen Players in the Ocean - A Field Guide to Water Chemistry and Marine Microbiology

Here we introduce a series of thoroughly tested and well standardized research protocols adapted for use in remote marine environments. The sampling protocols include the assessment of resources available to the microbial community (dissolved organic carbon, particulate organic matter, inorganic nutrients), and a comprehensive description of the viral and bacterial communities (via direct viral and microbial counts, enumeration of autofluorescent microbes, and construction of viral and microbial metagenomes). We use a combination of methods, which represent a dispersed field of scientific disciplines comprising already established protocols and some of the most recent techniques developed. Especially metagenomic sequencing techniques used for viral and bacterial community characterization, have been established only in recent years, and are thus still subjected to constant improvement. This has led to a variety of sampling and sample processing procedures currently in use. The set of methods presented here provides an up to date approach to collect and process environmental samples. Parameters addressed with these protocols yield the minimum on information essential to characterize and understand the underlying mechanisms of viral and microbial community dynamics. It gives easy to follow guidelines to conduct comprehensive surveys and discusses critical steps and potential caveats pertinent to each technique.

Here, we present a comprehensive protocol to assess the organic and inorganic nutrient availability and the abundance and structure of microbial and viral communities in remote marine environments.

揭开看不见的玩家在海洋 - 一个领域指南水化学和海洋微生物

Here we introduce a series of thoroughly tested and well standardized research protocols adapted for use in remote marine environments. The sampling ...

Chemotactic Response of Marine Micro-Organisms to Micro-Scale Nutrient Layers

The degree to which planktonic microbes can exploit microscale resource patches will have considerable implications for oceanic trophodynamics and biogeochemical flux. However, to take advantage of nutrient patches in the ocean, swimming microbes must overcome the influences of physical forces including molecular diffusion and turbulent shear, which will limit the availability of patches and the ability of bacteria to locate them. Until recently, methodological limitations have precluded direct examinations of microbial behaviour within patchy habitats and realistic small-scale flow conditions. Hence, much of our current knowledge regarding microbial behaviour in the ocean has been procured from theoretical predictions. To obtain new information on microbial foraging behaviour in the ocean we have applied soft lithographic fabrication techniques to develop 2 microfluidic devices, which we have used to create (i) microscale nutrient patches with dimensions and diffusive characteristics relevant to oceanic processes and (ii) microscale vortices, with shear rates corresponding to those expected in the ocean. These microfluidic devices have permitted a first direct examination of microbial swimming and chemotactic behaviour within a heterogeneous and dynamic seascape. The combined use of epifluorescence and phase contrast microscopy allow direct examinations of the physical dimensions and diffusive characteristics of nutrient patches, while observing the population-level aggregative response, in addition to the swimming behaviour of individual microbes. These experiments have revealed that some species of phytoplankton, heterotrophic bacteria and phagotrophic protists are adept at locating and exploiting diffusing microscale resource patches within very short time frames. We have also shown that up to moderate shear rates, marine bacteria are able to  fight the flow  and swim through their environment at their own accord. However, beyond a threshold high shear level, bacteria are aligned in the shear flow and are less capable of swimming without disturbance from the flow. Microfluidics represents a novel and inexpensive approach for studying aquatic microbial ecology, and due to its suitability for accurately creating realistic flow fields and substrate gradients at the microscale, is ideally applicable to examinations of microbial behaviour at the smallest scales of interaction.  We therefore suggest that microfluidics represents a valuable tool for obtaining a better understanding of the ecology of microorganisms in the ocean.

The fabrication of microfluidic channels and their implementation in experiments for studying the chemotactic foraging behaviour of marine microbes within a patchy nutrient seascape and the swimming behaviour of bacteria within shear flow are described.

海洋微生物的趋化反应的微观尺度的营养层

The degree to which planktonic microbes can exploit microscale resource patches will have considerable implications for oceanic trophodynamics and ...

生物学

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in nutrient and gas cycles. After cores with intact sediment-water interfaces are collected, they are submerged in incubation tanks and kept under aerobic conditions at in situ temperatures. To initiate a time course of overlying water chemistry, cores are sealed without bubbles using a top cap with a suspended stirrer. Time courses of 4-7 sample points are used to determine the rate of sediment water exchange. Artificial illumination simulates day-time conditions for shallow photosynthetic sediments, and in conjunction with dark incubations can provide net exchanges on a daily basis. The net measurement of N2 is made possible by sampling a time course of dissolved gas concentrations, with high precision mass spectrometric analysis of N2:Ar ratios providing a means to measure N2 concentrations. We have successfully applied this approach to lakes, reservoirs, estuaries, wetlands and storm water ponds, and with care, this approach provides valuable information on biogeochemical balances in aquatic ecosystems.

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Here, we present small core incubations for the measurement of sediment-water gas and solute exchange. These will provide reliable measurements of sediment-water exchange that assess the role of sediment in influencing biological and biogeochemical processes in aquatic ecosystems.

Ø的底栖交易所<sub&gt; 2</sub&gt;，N<sub&gt; 2</sub&gt;和营养盐使用小的核心孵化

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in ...

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to characterize. However, to understand the thermodynamic and kinetic controls on greenhouse gas (carbon dioxide [CO2] and methane [CH4]) production resulting from the decomposition of NOM, a molecular-level characterization coupled with microbial proteome analyses is necessary. Further, climate and environmental changes are expected to perturb natural ecosystems, potentially upsetting complex interactions that influence both the supply of organic matter substrates and the microorganisms performing the transformations. A detailed molecular characterization of the organic matter, microbial proteomics, and the pathways and transformations by which organic matter is decomposed will be necessary to predict the direction and magnitude of the effects of environmental changes. This article describes a methodological throughput for comprehensive metabolite characterization in a single sample by direct injection Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), gas chromatography mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography mass spectrometry (LC-MS), and proteomics analysis. This approach results in a fully-paired dataset which improves statistical confidence for inferring pathways of organic matter decomposition, the resulting CO2 and CH4 production rates, and their responses to environmental perturbation. Herein we present results of applying this method to NOM samples collected from peatlands; however, the protocol is applicable to any NOM sample (e.g., peat, forested soils, marine sediments, etc.).

This protocol describes a single throughput for complementary analytical and omics techniques culminating in a fully-paired characterization of natural organic matter and microbial proteomics in different ecosystems. This approach permits robust comparisons for identifying metabolic pathways and transformations important for describing greenhouse gas production and predicting responses to environmental change.

用于表征复杂天然有机物混合物的单吞吐量互补高分辨率分析技术

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to ...

A Low-Cost Method of Measuring the In Situ Primary Productivity of Periphyton Communities of Lentic Waters

Measuring the in situ primary productivity of periphyton during the growing season gradient can elucidate the quantitative effect of environmental drivers (mainly phosphorus concentration and light intensity) and species composition on primary productivity. Primary productivity is mainly driven by light intensity, temperature, availability of nutrients, and distribution of the ionic species of the carbonate system in the respective depths of the euphotic zone. It is a complex system that is very difficult to simulate in the laboratory. This cheap, transportable, and easy-to-build floating barge allows measuring the primary productivity accurately-directly under the actual natural conditions. The methodology is based on measuring the primary productivity in real time using noninvasive oxygen sensors integrated into tightly sealed glass jars, enabling online oxygen flux monitoring and providing new insights into metabolic activities. Detailed seasonal in situ measurements of gross primary productivity of microbial mats (or other benthic organisms) can improve current knowledge of the processes controlling primary productivity dynamics in lentic waters.

A Low-Cost Method of Measuring the In Situ Primary Productivity of Periphyton Communities of Lentic Waters

Presented here is a cost-effective and transportable method/facility for measuring the primary productivity of microbial mats under actual in situ environmental temperature and light conditions. The experimental setup is based on widely available materials and can be used under various conditions while offering the advantages of laboratory-based models.

一种低成本的透镜水周边植物群落原 位初级生产力 测量方法

Measuring the in situ primary productivity of periphyton during the growing season gradient can elucidate the quantitative effect of environmental drivers ...

Dissolved Solute Sampling Across an Oxic-Anoxic Soil-Water Interface Using Microdialysis Profilers

Biogeochemical processes shift rapidly in both spatial (millimeter scale) and temporal (hour scale to day scale) dimensions at the oxic-anoxic interface in response to disturbances. Deciphering the rapid biogeochemical changes requires in situ, minimally invasive tools with high spatial and temporal sampling resolution. However, the available passive sampling devices are not very useful in many cases either due to their disposable nature or the complexity and extensive workload for sample preparation.
To address this problem, a microdialysis profiler with 33 individual polyethersulfone nanomembrane tubes (semipermeable, &#60;20 nm pore size) integrated into the one-dimensional skeleton (60 mm) was established to iteratively sample the dissolved compounds in porewater across the soil-water interface at a high resolution of 1.8 mm (outer diameter plus one spacing, i.e., 0.1 mm between probes). The sampling mechanism is based on the principle of concentration gradient diffusion. The automatic loading of degassed water allows minimal disturbance to the chemical species across the oxic-anoxic interface.
This paper describes the procedures of device setup and continuous porewater sampling across the soil-water interface on a daily basis. Concentration-depth profiles were selectively measured before (on Day 6) and after (on Day 7) disturbances induced by irrigation. The results showed that concentration-depth profiles were undergoing rapid changes, especially for redox-sensitive elements (i.e., iron and arsenic). These protocols can help investigate the biogeochemical responses across the soil-water interface under various disturbances caused by physical, chemical, and biological factors. The paper thoroughly discusses the advantages and disadvantages of this method for potential use in the environmental sciences.

A microdialysis profiler is described to sample dissolved porewater solutes across an oxic-anoxic soil-water interface in situ with minimal disturbance. This device is designed to capture rapid changes in concentration-depth profiles induced by disturbances at the soil-water interface and beyond.

使用微透析剖面仪在氧化-缺氧土壤-水界面上进行溶解溶质采样

Biogeochemical processes shift rapidly in both spatial (millimeter scale) and temporal (hour scale to day scale) dimensions at the oxic-anoxic interface ...

用于营养物管理的生物地球化学数据的集成可视化

Visualization of Productivity Zones Based on Nitrogen Mass Balance Model in Narragansett Bay, Rhode Island

Primary productivity in the coastal regions, linked to eutrophication and hypoxia, provides a critical understanding of ecosystem function. Although primary productivity largely depends on riverine nutrient inputs, estimation of the extent of riverine nutrient influences in the coastal regions is challenging. A nitrogen mass balance model is a practical tool to evaluate coastal ocean productivity to understand biological mechanisms beyond data observations. This study visualizes the biological production zones in Narragansett Bay, Rhode Island, USA, where hypoxia frequently occurs, by applying a nitrogen mass balance model. The Bay is divided into three zones - brown, green, and blue zones - based on primary productivity, which are defined by the mass balance model results. Brown, green, and blue zones represent a high physical process, a high biological process, and a low biological process zone, depending on river flow, nutrient concentrations, and mixing rates. The results of this study can better inform nutrient management in the coastal ocean in response to hypoxia and eutrophication.

作者聚焦:了解河流氮的影响和初级生产力以实现有效的营养管理

Here, we aim to visualize the zonation of biological productivity in Narragansett Bay, Rhode Island, based on the nitrogen mass balance model. The results will inform nutrient management in the coastal regions to reduce hypoxia and eutrophication.

基于氮质量平衡模型的罗德岛州纳拉甘西特湾生产力区可视化

Primary productivity in the coastal regions, linked to eutrophication and hypoxia, provides a critical understanding of ecosystem function. Although ...

了解溶解有机物生物地球化学通过

摘要

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设计一个连续和操作

揭开看不见的玩家在海洋 - 一个领域指南水化学和海洋微生物

海洋微生物的趋化反应的微观尺度的营养层

Ø的底栖交易所

用于表征复杂天然有机物混合物的单吞吐量互补高分辨率分析技术

一种低成本的透镜水周边植物群落原位初级生产力测量方法

使用微透析剖面仪在氧化-缺氧土壤-水界面上进行溶解溶质采样

基于氮质量平衡模型的罗德岛州纳拉甘西特湾生产力区可视化

基于氮质量平衡模型的罗德岛州纳拉甘西特湾生产力区可视化

基于氮质量平衡模型的罗德岛州纳拉甘西特湾生产力区可视化

了解溶解有机物生物地球化学通过

摘要

探索更多视频

设计一个连续和操作

揭开看不见的玩家在海洋 - 一个领域指南水化学和海洋微生物

海洋微生物的趋化反应的微观尺度的营养层

Ø的底栖交易所

用于表征复杂天然有机物混合物的单吞吐量互补高分辨率分析技术

一种低成本的透镜水周边植物群落原 位初级生产力 测量方法

使用微透析剖面仪在氧化-缺氧土壤-水界面上进行溶解溶质采样

基于氮质量平衡模型的罗德岛州纳拉甘西特湾生产力区可视化

基于氮质量平衡模型的罗德岛州纳拉甘西特湾生产力区可视化

基于氮质量平衡模型的罗德岛州纳拉甘西特湾生产力区可视化

一种低成本的透镜水周边植物群落原位初级生产力测量方法