Chlorophyll a from phytoplankton and microzooplankton experiments on the RVIB Nathaniel B. Palmer NBP0608 cruise in the Ross Sea, Southern Ocean during 2006 (CORSACS project, Antarctic microzooplankton project)

<p><strong>Experiment Description:</strong></p> <p>Experiments were conducted during the CORSACS (Controls On Ross Sea Algal Community Structure) expedition in November 2006 to the Ross Sea, Antarctica, onboard the RVIB Nathaniel B. Palmer (cruise NBP-0608). Water was collected at 76 50'S, 173 47'E using a trace metal clean towed-intake surface water Teflon diaphragm pumping system (Bruland et al., 2005). Sea surface temperature at this location was -1.5 deg C at the time of water collection. Water was prescreened through acid-washed 200micrometer Nitex mesh to eliminate large zooplankton and collected into a 50 L mixing carboy. Collected water was gently mixed and dispensed into 24 4.5 L acid washed trace metal clean clear polycarbonate bottles for incubation. Four treatments were used with six replicates per treatment. Bottles were incubated in two temperature controlled deck-board incubators housed in deck vans under halogen lights (Feng et al., 2009; Hare et al., 2007). Irradiance was 2000 uE m2 s-1 without screening. Incubators were screened with neutral density filter and measured irradiances in the four treatments were:<br /> Low light, low temperature (LLLT): 61 uE m2 s-1<br /> Low light, high temperature (LLHT): 45 uE m2 s-1<br /> High light, low temperature (HLLT): 321 uE m2 s-1<br /> High light, high temperature (HLHT): 320 uE m2 s-1<br /> One incubator was maintained at 0 deg C, while the temperature in the other was gradually increased to 4 deg C over the course of 24 h. Bottles were incubated for eight days. All sampling occurred under a laminar flow hood using trace metal clean techniques.<br /> <br /> Bruland, K.W., E.L. Rue, G.J. Smith, and G.R. DiTullio. 2005. Iron, macronutrients and diatom blooms in the Peru upwelling regime: brown and blue waters of Peru. Marine Chemistry 93: 81-103.<br /> <br /> Feng, Y., C.E. Hare, K. Leblanc, G.R. DiTullio, P.A. Lee, S.W. Wilhelm, J. Sun, J.M. Rose, N. Nemcek, I. Benner, and D.A. Hutchins. 2009. The effects of increased pCO2 and temperature on the North Atlantic Spring Bloom: I. The phytoplankton community and biogeochemical response. Marine Ecology Progress Series 388: 13-25.<br /> <br /> Hare, C.E., K. Leblanc, G.R. DiTullio, R.M. Kudela, Y. Zhang, P.A. Lee, S.F. Riseman, and D.A. Hutchins. 2007. Consequences of increased temperature and CO2 for phytoplankton community structure in the Bering Sea. Marine Ecology Progress Series 352: 9-16.<br /> &nbsp;</p><p><strong>实验描述：</strong></p> <p>本实验于2006年11月搭载“纳撒尼尔·B·帕尔默号”科考船（RVIB Nathaniel B. Palmer，航次NBP-0608），随罗斯海藻类群落结构控制考察（Controls On Ross Sea Algal Community Structure，缩写CORSACS）前往南极罗斯海开展。研究人员采用痕量金属洁净型拖曳取水表层水特氟龙（Teflon）隔膜泵送系统（Bruland等，2005），在南纬76°50′、东经173°47′处采集表层海水，采样时该站位的海水表层温度为-1.5℃。</p> <p>采集所得海水先经酸洗处理后的200微米尼泰克斯（Nitex）滤网预过滤，以去除大型浮游动物，随后收集至50升混合储液桶中。将混匀后的海水分装至24个经酸洗的4.5升痕量金属洁净型透明聚碳酸酯（polycarbonate）培养瓶中进行培养。实验共设置4种处理组，每组设置6个重复样。</p> <p>培养瓶被安置于两个安装在甲板舱室内的控温甲板培养箱中，以卤素灯提供照明（Feng等，2009；Hare等，2007）。未加装滤膜时的初始辐照度为2000 μE·m⁻²·s⁻¹。培养箱加装中性密度滤膜过滤光照后，4个处理组的实测辐照度如下：<br>弱光低温组（LLLT）：61 μE·m⁻²·s⁻¹<br>弱光高温组（LLHT）：45 μE·m⁻²·s⁻¹<br>强光低温组（HLLT）：321 μE·m⁻²·s⁻¹<br>强光高温组（HLHT）：320 μE·m⁻²·s⁻¹</p> <p>其中一个培养箱维持恒温0℃，另一个培养箱的温度在24小时内逐步升高至4℃。所有培养周期为8天，全部采样操作均在层流超净台中采用痕量金属洁净技术完成。</p> <p><br> Bruland, K.W., E.L. Rue, G.J. Smith, and G.R. DiTullio. 2005. 秘鲁上升流区的铁、大量营养盐与硅藻水华：秘鲁的褐水与蓝水. 《海洋化学》（Marine Chemistry）93: 81-103.</p> <p><br> Feng, Y., C.E. Hare, K. Leblanc, G.R. DiTullio, P.A. Lee, S.W. Wilhelm, J. Sun, J.M. Rose, N. Nemcek, I. Benner, and D.A. Hutchins. 2009. pCO₂与温度升高对北大西洋春季水华的影响：I. 浮游植物群落与生物地球化学响应. 《海洋生态学进展系列》（Marine Ecology Progress Series）388: 13-25.</p> <p><br> Hare, C.E., K. Leblanc, G.R. DiTullio, R.M. Kudela, Y. Zhang, P.A. Lee, S.F. Riseman, and D.A. Hutchins. 2007. 温度与CO₂升高对白令海浮游植物群落结构的影响. 《海洋生态学进展系列》（Marine Ecology Progress Series）352: 9-16.</p> &nbsp;