Biogenic silica production and diatom dynamics in the Svalbard region during spring 2016

Raw data used in the publication of "Biogenic silica production and diatom dynamics in the Svalbard region during spring 2016". ARCEx. The Research Centre for Arctic Petroleum Exploration, ARCEx, is a research collaboration between academia and industry with support from the Research Council and Norwegian authorities. Through a common effort, the project contributes to the understanding of the geology and resource potential of the high north, the development of new geophysical exploration techniques suitable for the Arctic and new models for environmental risk connected to operations in the north. Education and training is an integrated part of ARCEx. ARCEx is hosted by UiT The Arctic University of Norway in Tromsø. Cruise goal and duration. The overarching goal of the ARCEx cruise was to study the pelagic and benthic ecosystem during Arctic spring bloom scenarios in fjords at western Svalbard (van Mijenfjorden and Hornsund), a coastal scenario (Storfjorden) and the western Barents Sea (in the Arctic influenced Erik Eriksen Strait, the Polar Front and at an Atlantic influenced location). This study was conducted onboard the FF Helmer Hanssen between 17 and 29 May 2016 with Dr. Ingrid Wiedmann serving as Chief Scientist. Data collection. All samples reported in this data set were collected either using a water-column CTD Rosette sampler with Niskin bottles or short-duration sediment traps. The CTD package was a Seabird Electronics (SBE) 911plus with a photosynthetically active radiation sensor (Biospherical/Licor, SN 1060). Discreet samples were collected at targeted depths using 5-L Niskin samplers secured to the CTD Rosette system. Once on deck, water was sampled directly from the Niskin samplers to be processed for the measurements and methods described. The vertical flux of particulates was assessed by filtering water from the short-term (<1 day) deployed sediment traps (KC Denmark). Sediment trap cylinders (~72mm internal diameter, ~450mm length, ~1:8 L volume) were deployed at three to seven depths ranging between 20 and 150–200 m, based on bathymetry. At the two fjord stations (van Mijenfjorden, Hornsund), the sediment trap array was anchored to the bottom. In the more open regions of the drift ice covered Arctic station (Erik Eriksen Strait) and the open water stations in the Atlantic waters in the wester Barents Sea, the sediment trap array was anchored to an ice-floe and freely drifting, respectively. After recovery of the sediment traps, all cylinder contents at a particular depth were pooled in a acid-cleaned container, homogenized and subsampled for the measurements and methods described.
Abstract. Diatoms are generally the dominant contributors to the Arctic Ocean spring bloom, which is a key event in regional food webs in terms of capacity for secondary production and organic matter export. Dissolved silicic acid is an obligate nutrient for diatoms and has been declining in the European Arctic since the early 1990s. The lack of regional silicon cycling information precludes understanding the consequences of such changes for diatom productivity during the Arctic spring bloom. This study communicates the results from a cruise in the European Arctic around Svalbard, which reports the first concurrent data on biogenic silica production and export, export of diatom cells, the degree of kinetic limitation by ambient silicic acid, and diatom contribution to primary production. Regional biogenic silica production rates were significantly lower than those achievable in the Southern Ocean and silicic acid concentration limited the biogenic silica production rate in 95% of samples. Compared to diatoms in the Atlantic subtropical gyre, regional diatoms are less adapted for silicic acid uptake at low concentration, and at some stations during the present study, silicon kinetic limitation may have been intense enough to limit diatom growth. Thus, silicic acid can play a critical role in diatom spring bloom dynamics. The diatom contribution to primary production was variable, ranging from < 10% to ∼ 100% depending on the bloom stage and phytoplankton composition. While there was agreement with previous studies regarding the export rate of diatom cells, we observed significantly elevated biogenic silica export. Such a discrepancy can be resolved if a higher fraction of the diatom material exported during our study was modified by zooplankton grazers. This study provides the most direct evidence to date suggesting the important coupling of the silicon and carbon cycles during the spring bloom in the European Arctic.

本数据集收录了用于发表《2016年春季斯瓦尔巴德地区生物成因二氧化硅的生产及硅藻动态变化》一文的原始数据。ARCEx（北极石油勘探研究中心）是学术界与产业界之间的研究合作，得到了研究委员会和挪威当局的支持。通过共同努力，该项目致力于加深对北极地质和资源潜力的理解，开发适用于北极的新型地球物理勘探技术，以及与北部运营相关的环境风险评估模型。教育及培训是ARCEx项目的重要组成部分。ARCEx由挪威特罗姆瑟的挪威北极大学（UiT）承办。巡航目标与持续时间。ARCEx巡航的总体目标是研究斯瓦尔巴德西部峡湾（范米耶恩峡湾和霍恩松德）的浮游和底栖生态系统在北极春季浮游生物爆发情景下的动态变化，沿海情景（斯托尔峡湾）以及巴伦支海西部（受北极影响的埃里克·埃里克森海峡、极锋以及受大西洋影响的区域）。该研究于2016年5月17日至29日在FF Helmer Hanssen号船上完成，Ingrid Wiedmann博士担任首席科学家。数据收集。本数据集中报告的所有样本均使用水柱CTD罗塞特采样器（配备Niskin瓶）或短期沉积物收集器收集。CTD设备为Seabird Electronics（SBE）911plus，配备光合有效辐射传感器（Biospherical/Licor，SN 1060）。离散样本通过固定在CTD罗塞特系统上的5升Niskin采样器在目标深度采集。一旦登上甲板，水样直接从Niskin采样器中取出，用于后续的测量和方法处理。通过过滤短期（<1天）部署的沉积物收集器中的水样来评估颗粒物的垂直通量。沉积物收集器圆柱体（内部直径约72mm，长度约450mm，体积约1:8 L）在20至150-200米的三个至七个深度处部署，基于海底地形。在两个峡湾站（范米耶恩峡湾、霍恩松德），沉积物收集器阵列锚定在海底。在更多开阔的浮冰覆盖的北极站（埃里克·埃里克森海峡）以及巴伦支海西部大西洋水域的开阔水站，沉积物收集器阵列分别锚定在冰原和自由漂流的冰块上。在回收沉积物收集器后，特定深度的所有圆柱内容物均汇总到一个酸洗过的容器中，进行均质化并分样进行后续的测量和方法处理。

摘要。硅藻通常是对北极海洋春季浮游生物爆发贡献最大的生物，在区域食物网中，它是次级生产能力和有机物质输出能力的关键事件。溶解硅酸是硅藻的必需营养素，自20世纪90年代初以来，欧洲北极地区的溶解硅酸含量一直在下降。由于缺乏区域硅循环信息，无法理解这种变化对北极春季浮游生物生产力的影响。本研究报告了在欧洲北极斯瓦尔巴德附近的一次巡航结果，首次同时报告了生物成因二氧化硅的生产和输出、硅藻细胞输出、环境硅酸浓度限制的动力学限制程度以及硅藻对初级生产力的贡献。区域生物成因二氧化硅生产率显著低于南大洋的生产率，95%的样品中硅酸浓度限制了生物成因二氧化硅的生产率。与大西洋亚热带环流中的硅藻相比，本区域硅藻对低浓度硅酸的吸收适应性较差，在本次研究的一些站点，硅的动力学限制可能已经足够强烈，以至于限制了硅藻的生长。因此，硅酸可以在硅藻春季浮游生物爆发动态中发挥关键作用。硅藻对初级生产力的贡献变化较大，从<10%到∼100%，具体取决于浮游生物爆发阶段和浮游植物组成。尽管与先前关于硅藻细胞输出速率的研究结果一致，但我们观察到生物成因二氧化硅的输出显著增加。如果本次研究中输出的硅藻物质中有更高比例被浮游动物食草者修改，那么这种差异可以得到解释。本研究提供了迄今为止最直接的证据，表明硅和碳循环在春季北极欧洲爆发中的重要作用耦合。