Chlorophyll measurements from the MesoHux mesocosm experiment held in May 2017

<p>Water samples for chlorophyll extraction were collected from the mesocosms via a 5 L Niskin. Chlorophyll samples were filtered in triplicate through a 25mm Glass Fiber Filter (GFF), and immediately extracted in 6 mL of ethanol for 12-18 hours in the dark at room temperature. After extraction, filters were removed from the sample, and the fluorescence of the sample was read on a Turner AU10. The sample was then acidified with 1 drop of 10% HCL and re-read on the same instrument. The fluorometer was calibrated prior to using with a chlorophyll standard purchased from Sigma.</p>

<p>Mesocosm treatments are as follows:<br />
P-limited: N:P added in a 60:1 ratio during the first 3 days of the experiment, no shading<br />
Redfield: N:P added in a 16:1 ratio during the first 3 days of the experiment, no shading<br />
Shaded: N:P added in a 16:1 ratio during the first 3 days of the experiment, top shaded of the mesocosm added on May 20, 2017<br />
Ambient: no nutrients added, no shading<br />
Samples were taken from either 1m, 5m, or from sediment from settling cones. Samples were noted in the Sample Depth (m) column.</p>

<p>用于叶绿素提取的水样通过5L Niskin采水器从中宇宙（mesocosms）中采集。叶绿素样本以三份重复的方式通过25mm玻璃纤维滤膜（Glass Fiber Filter, GFF）过滤，随后立即置于6mL乙醇中，在室温黑暗条件下提取12-18小时。提取完成后，移除样本中的滤膜，使用Turner AU10仪器读取样本的荧光值。接着向样本中加入1滴10%盐酸（HCL）进行酸化，并在同一仪器上再次读取。荧光计（fluorometer）在使用前已通过Sigma公司购买的叶绿素标准品进行校准。</p><p>中宇宙处理如下：<br>磷限制组（P-limited）：实验前3天添加氮磷比为60:1的营养盐，不遮光<br>Redfield组：实验前3天添加氮磷比为16:1的营养盐，不遮光<br>遮光组（Shaded）：实验前3天添加氮磷比为16:1的营养盐，于2017年5月20日对中宇宙顶部进行遮光处理<br>环境对照组（Ambient）：不添加营养盐，不遮光<br>样本采集自1m、5m水层或沉降锥中的沉积物。样本信息记录于样本深度（m）列中。</p>