Insights into biogeochemical transformations and fluxes from high-frequency ocean time-series data.

从高频海洋时间序列数据中洞察生物地球化学转变和通量。

• 批准号: RGPIN-2021-04332
• 负责人: Wallace, Douglas
• 金额: $ 3.72万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761603
• 关键词: Insights; into; biogeochemical; transformations; fluxes

The research will examine ocean cycling of carbon, nitrogen, oxygen and iodine. Oxygen and carbon will be studied in the Labrador Sea, where wintertime deep mixing creates potential for rapid, climate-sensitive transfer of oxygen, anthropogenic CO2 and organic carbon to the ocean interior. The cycling of nitrogen and iodine will be studied in Bedford Basin, Nova Scotia, a 70m deep coastal fjord, adjacent to Halifax. The research will be based on time-series of chemical, physical and biological parameters from: a) an autonomous, multidisciplinary observatory in the deepwater formation region of the Labrador Sea which is a key region for delivery of O2 and anthropogenic CO2 to the deep ocean; b) a multidisciplinary, weekly time-series from the seasonally-stratified Bedford Basin, whose nitrogen cycle is impacted by humankind and in which both nitrogen and iodine undergo major seasonal transformation. Deployment of the SeaCycler profiling winch and sensor package in the Labrador Sea (summer 2021), will provide high-resolution profiles (0-150m; 1-4 times per day for a year) of bio-optical properties, dissolved gases (CO2 and O2), nitrate, phosphate, temperature, salinity and turbulence, as well as estimates of zooplankton biomass. The SeaCycler will be operated in parallel with fixed-depth measurement of pH, alkalinity, pCO2 at a nearby mooring which will also be equipped (by other investigators) with a phytoplankton sampler allowing species succession to be related to chemical/physical data. HQP will use the new data as well as data from an earlier deployment to examine: 1) the fraction of net community production exported to the deep ocean by winter mixing (compared to settling via the biological carbon pump); 2) factors that explain the timing of the spring bloom; 3) the organic carbon export efficiency after seasonal stratification, based on nutrient, carbon and oxygen budgets above and below the euphotic zone. Given constrained exchanges and manageable size, Bedford Basin has characteristics of a large natural mesocosm so that time-series allow detailed examination of processes underlying speciation changes as well as fluxes of nitrogen and iodine. The time-series will provide context for the HQP projects which will involve repeated, short-term experimental manipulations to test and refine understanding and parameterization of chemical and microbially-mediated transformations (e.g. nitrification; iodate reduction). In both locations, the time-series provide an environment for multidisciplinary teams of HQP to work on complementary projects. The research will deliver: (a) tests, with comprehensive in-situ data, of diverse hypotheses for initiation of spring phytoplankton blooms, debated since the 1950's; (b) understanding of the sensitivity to climate change of organic carbon and oxygen delivery to the deep ocean via deep-mixing; (c) understanding of controls of nitrogen and iodine speciation and fluxes in the coastal ocean.

该研究将检查碳，氮，氧和碘的海洋循环。氧气和碳将在拉布拉多海进行研究，冬季深层混合为快速，气候敏感的氧气，人为二氧化碳和有机碳传递到海洋内部的潜力。氮和碘的循环将在新斯科舍省的贝德福德盆地进行研究，这是一个与哈利法克斯相邻的70m深沿海峡湾。该研究将基于：a）在拉布拉多海深水形成区域中的化学，物理和生物学参数的时间序列，这是将O2和人为CO2传递到深海的关键区域； b）来自季节性分层的贝德福德盆地的多学科，每周的时间序列，其氮周期受人类的影响，氮和碘经历了重大的季节性转变。在拉布拉多海（2021年夏季）部署Seacycler分析绞车和传感器套件，将提供高分辨率的概况（0-150m；每年每天1-4次）生物光学特性，溶解气体（CO2和O2）（CO2和O2），硝酸盐，硝酸盐，磷酸盐，磷酸盐，温度，含量，含量，盐分，盐酸和涡轮均等，以及Zoop的估计。 Seacycler将与附近系泊台的pH，碱度，PCO2的固定深度测量并联，该系列也将（其他研究人员）配备了浮游植物采样器，允许物种继承与化学/物理数据有关。 HQP将使用较早部署的新数据以及数据来检查：1）通过冬季混合（与通过生物碳泵结算相比，通过冬季混合出口到深海的净社区生产的比例）； 2）解释春天时机的因素； 3）季节性分层后的有机碳出口效率，基于舒适区以上和下方的营养，碳和氧气预算。 鉴于限制的交换和可管理的规模，贝德福德盆地具有大型天然中库的特征，因此时间序列可以详细检查物种形成变化的过程以及氮和碘的通量。时间序列将为HQP项目提供背景，该项目将涉及重复的短期实验操作，以测试和完善化学和微生物介导的转换的理解和参数化（例如硝化；碘化材料还原）。在两个地点，时间序列为HQP的多学科团队提供了一个互补项目的环境。这项研究将提供：（a）具有综合的原位数据，对春季浮游植物开花的不同假设进行了全面的测试，自1950年代以来就进行了辩论； （b）了解有机碳和氧气递送到深海的敏感性通过深层混合； （c）理解沿海海洋中氮和碘形物种形成和通量的控制。