Tracking Arctic marine productivity across the Holocene - Anthropocene transition using novel compound-specific stable isotope techniques

使用新型化合物特异性稳定同位素技术跟踪整个全新世-人类世转变的北极海洋生产力

• 批准号: RGPIN-2018-05590
• 负责人: Sherwood, Owen
• 金额: $ 2.99万
• 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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=688394
• 关键词: Tracking; Arctic; marine; productivity; across

The overall goal of my research program is to develop, test and apply novel stable isotopic techniques for tracking long-term changes in primary productivity in the Arctic and sub-Arctic Oceans. By the year 2040, Arctic summer sea ice is projected to disappear completely for the first time in perhaps the last 13 million years. It remains unclear if primary productivity will increase or decrease in a future ice-free Arctic. This has urgent global importance for predicting fisheries yields and for mitigation of greenhouse gas emissions via biological sequestration of CO2 to the deep ocean. Loss of ice cover should lead to increases in photosynthetic potential; however, nutrient limitation and loss of habitat for highly productive ice algae could negate any gains in productivity made from longer ice-free growing seasons. Our understanding of physical-biological processes and feedbacks controlling marine productivity are limited by difficulty accessing the remote Arctic environment in all but a narrow window of summer, satellite remote sensors that cannot see deeper than 25 m into the water column, and an acute lack of long-term (multi-decadal) scientific observations. My research program directly addresses these ongoing challenges to scientific progress in two key ways. First, we make use of annual resolution paleo-records contained in the skeletons of deep-sea corals that feed on the sinking flux of recently exported primary productivity. By combining these coral records with those from more traditional sediment cores, paleo-records of unprecedented length and resolution for Arctic waters will be generated. Second, we leverage the breakthrough interpretive potential of carbon and nitrogen stable isotopic analysis of amino acids preserved in corals and sediments. This novel methodology goes beyond traditional bulk isotope methods to provide a means for independently tracking four key processes at the base of marine foodwebs: nutrient source, autotroph community composition, organism trophic position, and microbial degradation. Reconstruction of these variables at annual resolution and over multi-centennial timespans will allow us to test hypotheses on the effect of changing sea ice conditions on nutrient availability and primary productivity. This research builds on a solid track record of innovative and impactful paleo-ecological reconstructions, which are essential for understanding, mitigating and adapting to climate change.

我的研究计划的总体目标是开发，测试和应用新颖的稳定同位素技术，以跟踪北极和亚北极海洋初级生产力的长期变化。到2040年，北极夏季海冰预计将在过去1300万年内首次完全消失。目前尚不清楚一级生产率在未来的无冰北极中是否会增加或降低。这对于预测渔业产量和通过将CO2的生物隔离为深海来预测渔业产量和缓解温室气体排放具有迫切的重要性。冰盖的损失应导致光合潜力的增加；但是，高生产性冰藻的营养限制和栖息地的丧失可能会抵消较长的无冰生长季节的生产力。我们对控制海洋生产力的物理生物学过程和反馈的理解受到限制，这是由于难以在夏季狭窄的窗户，卫星遥控传感器中访问偏远的北极环境，在水柱中无法深入25 m的卫星遥控传感器，以及急性缺乏长期（多年代）科学观测。我的研究计划以两种关键方式直接解决了对科学进步的持续挑战。首先，我们利用深海珊瑚骨骼中包含的年度分辨率古记录，这些曲线以最近出口的原发性生产力的下沉通量为食。通过将这些珊瑚记录与来自更传统的沉积物核心的记录相结合，将产生前所未有的长度和分辨率的古录制。其次，我们利用了保存在珊瑚和沉积物中的氨基酸的碳和氮稳定同位素分析的突破性解释潜力。这种新颖的方法超出了传统的同位同位素方法，可以提供一种在海洋食品基础上独立跟踪四个关键过程的方法：营养源，自动营养群落组成，有机营养位置和微生物降解。在年度分辨率和多个百年纪念时间的情况下重建这些变量将使我们能够测试有关改变海冰条件对养分可用性和主要生产率的影响的假设。这项研究以创新和有影响力的古生态重建的稳固记录为基础，这对于理解，缓解和适应气候变化至关重要。