Series 1A: Two-stressor effects on Tp-1335: Experiments to investigate the combined effect of light and temperature changes on the growth rate of Thalassiosira pseudonana CCMP

<p>Experiments were conducted to investigate the combined effect of light and temperature changes on the growth rate (mu) of <em>Thalassiosira</em> <em>pseudonana</em> CCMP 1335. <em>T.</em> <em>pseudonana</em> was grown in artificial seawater (ASW) (Kester et al.1967), enriched as in f/2 (Guillard 1975). Each of five experiments per series was conducted at a different temperature (13.4; 18.5; 24.4; 26.5; 22.5 C). At each temperature, cultures were kept on a 12-hour light 12-hour dark cycle under eight light intensities ranging from 35 umol/m^2/S&nbsp;to 140 umol/m^2/s. Optical density measurements (OD680 and OD720), dark-adapted Instantaneous Chlorophyll Fluorescence (F0) and the quantum yield (QY=Fv/Fm, where Fv is the maximal variable fluorescence and Fm is the maximal fluorescence intensity) and cell concentrations were determined daily at the end of the dark period. Cell counts were conducted in a hemocytometer on a microscope.</p>

<p>Date&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Expt#&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;Temperature (°C)<br />
04/15/2016&nbsp; &nbsp; 1&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;13.4<br />
05/30/2016&nbsp; &nbsp; 2 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 18.5<br />
07/31/2016&nbsp; &nbsp; 3 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 24.4<br />
08/20/2016&nbsp; &nbsp; 4 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 26.5<br />
08/22/2016&nbsp; &nbsp; 5 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 22.5</p>

本实验旨在探究光照与温度变化的联合效应对假微型海链藻（Thalassiosira pseudonana）CCMP 1335的生长速率（μ）的影响。实验采用人工海水（ASW，Kester等，1967）作为培养基质，并按照f/2配方（Guillard，1975）进行营养富集。每个实验系列设置5组独立实验，分别在13.4、18.5、24.4、26.5、22.5℃五个不同温度条件下开展。在每个温度条件下，培养物均维持12小时光照/12小时黑暗的光周期，设置8级光照强度，强度范围为35 μmol/(m²·s)至140 μmol/(m²·s)。在每个黑暗周期结束时，每日测定光密度（OD680与OD720）、暗适应瞬时叶绿素荧光（F0）、量子产率（QY=Fv/Fm，其中Fv为最大可变荧光，Fm为最大荧光强度）以及细胞浓度。细胞计数采用血球计数板在显微镜下完成。

| 实验日期 | 实验编号 | 温度(℃) |
|----------------|----------|---------|
| 2016/04/15 | 1 | 13.4 |
| 2016/05/30 | 2 | 18.5 |
| 2016/07/31 | 3 | 24.4 |
| 2016/08/20 | 4 | 26.5 |
| 2016/08/22 | 5 | 22.5 |