Collaborative Research: High resolution glider observations enable reassessment of export production in the oligotrophic Sargasso Sea

合作研究：高分辨率滑翔机观测能够重新评估寡营养马尾藻海的出口产量

• 批准号: 1850723
• 负责人: Michael Lomas
• 金额: $ 20.36万
• 依托单位: Bigelow Laboratory for Ocean Sciences
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1850723&HistoricalAwards=false
• 关键词: Collaborative; Research; resolution; glider; observations

Observations and measurements over several decades at locations like the Bermuda Atlantic Time-series Study (BATS) site have been important to fundamental understanding of the links between the physics, chemistry, and biology of the ocean. At the BATS site however, despite the long history of observations, a mystery remains: When and how is enough nitrogen delivered to surface waters to support the biological production that is observed? The investigators will use oxygen, nitrate, and micro-turbulence sensors on autonomous underwater gliders to sample continuously for twenty months at the BATS site in an effort to resolve this mystery. Gliders make it possible to measure processes at scales that can't be captured by monthly or biweekly sampling from a ship. Regular sampling by the BATS program will still be essential to the project, however, by providing opportunities for calibration and validation of the glider sensors as well as ship support for glider deployments and recoveries. The project will also leverage existing private funding from the BIOS-SCOPE project, a multi-institutional microbial marine biogeochemistry initiative at BATS, that will provide partial support for glider operations. The investigators will recruit and advise at least two NSF Research Experience for Undergraduates (REU) students each year, and will incorporate project themes and data into educational programs at their respective institutions. This project will apply new technologies to address several factors believed to perpetuate significant underestimates of nitrate delivery and particulate organic carbon (POC) exports in the Sargasso Sea. High-resolution glider-based observations will be used to estimate annual net community production (ANCP) through oxygen mass balance, and new production (NP) through nitrate mass balance, over a period spanning an annual cycle and two consecutive oligotrophic periods. Microstructure measurements will provide much-needed profiles of vertical diffusivity to accurately constrain fluxes of oxygen and nitrate and their variability over the annual cycle. Oxygen/argon ratio measurements will be used as independent estimates of biologically mediated oxygen changes and as constraints on glider-measured rates of oxygen concentration change. Assessments of phytoplankton characteristics by flow cytometry will be used to calibrate the gliders' optical sensors to in situ biological characteristics, so that variability in phytoplankton community structure and biomass can be discerned at the gliders' high temporal resolution and related to simultaneously measured NCP, NP, and physical water column structure, both above and below the euphotic zone. POC exports will be inferred from backscatter inventories in the deeper layers. The sum of observations will enable assessments of relationships among three independently measured proxies for the strength of the biological carbon pump and how the system responds to environmental forcing over the annual cycle, with particular focus on the stratified oligotrophic months.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

几十年来，在百慕大大西洋时间序列研究(BATS)站点等地点进行的观测和测量对于从根本上理解海洋的物理、化学和生物之间的联系非常重要。然而，在BATS现场，尽管有很长的观测历史，一个谜团仍然存在：何时以及如何向地表水输送足够的氮来支持观察到的生物生产？调查人员将使用自主水下滑翔机上的氧气、硝酸盐和微湍流传感器在BATS现场连续采样20个月，以努力解开这个谜团。滑翔机使以每月或每两周从船上采样无法捕捉到的尺度测量过程成为可能。然而，BATS计划的定期采样仍然对该项目至关重要，因为它为滑翔机传感器的校准和验证以及为滑翔机部署和回收提供船舶支持提供了机会。该项目还将利用来自基本输入输出系统范围项目的现有私人资金，该项目是BATS的一个多机构微生物海洋生物地球化学倡议，将为滑翔机的运营提供部分支持。调查人员将每年招募至少两名NSF本科生研究经验(REU)学生并为其提供建议，并将项目主题和数据纳入各自机构的教育计划。该项目将应用新技术来解决几个因素，这些因素被认为是导致马尾藻海硝酸盐输送和颗粒有机碳(POC)出口被严重低估的因素。基于滑翔机的高分辨率观测将被用来估计跨越一年周期和连续两个少营养期的年度净群落生产量(ANCP)和通过硝酸盐质量平衡估计的新生产量(NP)。微结构测量将提供急需的垂直扩散系数剖面，以准确地限制氧气和硝酸盐的通量及其在年度循环中的变化。氧/氩比的测量将被用作生物介导性氧气变化的独立估计，并作为滑翔机测量的氧气浓度变化率的约束。通过流式细胞仪对浮游植物特征的评估将用于校准滑翔机的光学传感器以原位生物特征，以便在滑翔机的高时间分辨率下识别浮游植物群落结构和生物量的变化，并与同时测量的NCP、NP和物理水柱结构相关，包括在真光区上方和下方。PoC出口将从更深层的后向散射库存中推断出来。观察结果的总和将能够评估生物碳泵强度的三个独立测量指标之间的关系，以及系统如何在年度周期中响应环境压力，特别是分层的少营养月份。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Extraction of Photosynthesis Parameters from Time Series Measurements of In Situ Production: Bermuda Atlantic Time-Series Study

从原位生产的时间序列测量中提取光合作用参数：百慕大大西洋时间序列研究

• DOI: 10.3390/rs10060915
• 发表时间: 2018
• 期刊: Remote Sensing
• 影响因子: 5
• 作者: Kovač, Žarko;Platt, Trevor;Sathyendranath, Shubha;Lomas, Michael
• 通讯作者: Lomas, Michael