metazoan zooplankton trophic level

This data was collected as a part of a mesocosm study to investigate the ecosystem impacts of ocean alkalinity enhancement, within the EU H2020 OceanNETs project. Nine mesocosms were deployed in Taliarte Harbour (Gran Canaria, Spain) and were regularly sampled using integrated water samplers between 10th September-25th October 2021. A gradient design was used in this experiment with a total of nine different alkalinity concentrations. Seawater alkalinity ranged between ambient (0 µeq kg-1 added alkalinity, OAE0) and 2400 µeq kg-1 additional alkalinity (OAE2400). The alkalinity levels increased in equal intervals of 300 µeq kg-1 across nine mesocosms (OAE0, OAE300, OAE600, OAE900, OAE1200, OAE1500, OAE1800, OAE2100, OAE2400). This data set contains metazoan zooplankton trophic level, calculated from zooplankton and particulate matter δ15N stable isotopes (‰ air). Metazoan zooplankton were sampled with apstein net (ø17cm, mesh size 55µm, 64.06285L) hauls taken every four days (except the first 11 days, when samples were only taken on days 1 and 11). Zooplankton were size fractioned and assessed in the correspondent size class (small: 55-200µm not assessed for trophic level; medium: 200-500µm; large: 500µm-3mm). Organisms were picked into functional groups within each size class, and their delta 15N isotope signal was measured using a mass spectrometer coupled to an elemental analyser: i) bulk zooplankton (MZP), which consisted of a random mix of all zooplankton, ii) and copepod zooplankton (COP). Delta 15N stable isotopes were also measured in acidified and non-acidified particulate matter filters (no consistent differences observed between them), assumed as the potential food for zooplankton. Here, we present the delta 15N measurements, and the calculated trophic level of the different metazoan zooplankton groups assessed (see Sanchez et al. in prep for further details on calculations). The experiment, which lasted 33 days, was divided into four response phases (see Sánchez et al. (in prep)): i) pretreatment (days 1 to 4, treatment was implemented on day 4), ii) immediate (days 5-10), iii) shorter term (days 11-22), iv) longer term (days 23 to 33).本数据集采集自欧盟“地平线2020”（EU H2020）计划下OceanNETs项目的一项围隔实验（mesocosm study），该实验旨在探究海洋碱度增强对海洋生态系统的影响。研究于西班牙大加那利岛塔利尔特港部署了9个围隔装置，并于2021年9月10日至10月25日期间，采用集成式采水器进行定期采样。本实验采用梯度设计，共设置9个不同的海水碱度浓度梯度：海水碱度范围涵盖本底水平（添加碱度为0 µeq kg⁻¹，记为OAE0）至2400 µeq kg⁻¹的额外添加碱度（记为OAE2400），9个围隔装置的碱度水平以300 µeq kg⁻¹的等间隔递增，依次为OAE0、OAE300、OAE600、OAE900、OAE1200、OAE1500、OAE1800、OAE2100、OAE2400。 本数据集包含根据浮游动物与颗粒物的δ¹⁵N稳定同位素（以大气为参考标准，单位为‰）计算得到的后生动物浮游动物营养级数据。后生动物浮游动物采用Apstein网（apstein net，直径17cm，网孔尺寸55μm，过滤体积64.06285L）进行拖网采样，采样间隔为每4天一次（实验前11天仅在第1天和第11天采样）。浮游动物按粒径分级，并在对应粒径级中开展分析：小型（55-200μm，未进行营养级分析）、中型（200-500μm）、大型（500μm-3mm）。在每个粒径级中，将生物划分为功能群，并利用与元素分析仪联用的稳定同位素质谱仪测定其δ¹⁵N同位素信号：① 总浮游动物（MZP），由所有浮游动物随机混合而成；② 桡足类浮游动物（COP）。 本研究还测定了酸化与非酸化颗粒物滤膜中的δ¹⁵N稳定同位素（两者未观测到一致的显著差异），该滤膜样品被视为浮游动物的潜在食物来源。本数据集提供了本次分析的不同后生动物浮游动物类群的δ¹⁵N测定值与计算得到的营养级数据（详细计算方法参见Sanchez等待发表文章）。 本实验持续33天，分为四个响应阶段（详见Sánchez等待发表文章）：① 预处理阶段（第1-4天，处理措施于第4天实施）；② 即时响应阶段（第5-10天）；③ 短期响应阶段（第11-22天）；④ 长期响应阶段（第23-33天）。