Chlorophyll-a, primary production rates, carbon concentrations and cell counts of coccolithophores, diatoms and microzooplankton measured in water samples from the North Atlantic during the M87/1 cruise in April 2012

The Deep Convection cruise repeatedly sampled two locations in the North Atlantic, sited in the Iceland and Norwegian Basins, onboard the RV Meteor (19 March - 2 May 2012). Samples were collected from multiple casts of a conductivity-temperature-depth (CTD) - Niskin rosette at each station. Water samples for primary production rates, community structure, chlorophyll a [Chl a], calcite [PIC], particulate organic carbon [POC] and biogenic silicic acid [BSi] were collected from predawn casts from six light depths (55%, 20%, 14%, 7%, 5% and 1% of incident PAR). Additional samples for community structure and ancillary parameters were collected from a second cast. Carbon fixation rates were determined using the 13C stable isotope method. Water samples for diatom and micro zooplankton counts, collected from the predawn casts, were preserved with acidic Lugol's solution (2% final solution) and counted using an inverted light microscope. Water samples for coccolithophore counts were collected onto cellulose nitrate filters and counted using polarising light microscopy. Water samples for Chl a analysis were filtered onto MF300 and polycarbonate filters and extracted in 90% acetone. PIC and BSi samples were filtered onto polycarbonate filters and analysed using an inductively coupled plasma emission optical spectrometer and a SEAL QuAAtro autoanalyser respectively.

“深对流”科考航次（Deep Convection cruise）于2012年3月19日至5月2日依托“流星号”（RV Meteor）科考船，在北大西洋冰岛海盆与挪威海盆的两个定点区域开展多次重复采样作业。每个站位均通过多次下放温盐深仪-尼斯金采水瓶架（conductivity-temperature-depth (CTD)-Niskin rosette）获取采样样本。用于测定初级生产速率、群落结构、叶绿素a（Chl a）、方解石（PIC）、颗粒有机碳（POC）与生物源硅酸（BSi）的水样，均取自6个光照深度下的黎明前采水作业，该6个光照深度分别为入射光合有效辐射（Photosynthetically Active Radiation，PAR）的55%、20%、14%、7%、5%与1%。群落结构与辅助参数的额外样本则通过第二次下放采水获取。碳固定速率采用13C稳定同位素法测定。用于硅藻与微型浮游动物计数的水样取自黎明前采水作业，以终浓度2%的酸性卢戈氏液（Lugol's solution）固定后，通过倒置光学显微镜完成计数。用于颗石藻计数的水样经硝酸纤维素滤膜过滤后，采用偏光光学显微镜进行计数。用于叶绿素a分析的水样经MF300滤膜与聚碳酸酯滤膜过滤后，以90%丙酮进行萃取。方解石（PIC）与生物源硅酸（BSi）样本经聚碳酸酯滤膜过滤后，分别通过电感耦合等离子体发射光谱仪与SEAL QuAAtro全自动化学分析仪完成分析。