Collaborative Research: Using Geochemical Tracers to Characterize the Effects of Wintertime Episodic Nutrient Inputs on Biological Activity in the Sargasso Sea

合作研究：使用地球化学示踪剂来表征冬季间歇性营养物输入对马尾藻海生物活动的影响

• 批准号: 0351651
• 负责人: William Jenkins
• 金额: $ 24.7万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0351651&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; Geochemical; Tracers

ABSTRACTOCE-0351651 / OCE 0351396Recent data suggest that in the Sargasso Sea the weekly passage of weather fronts leads to increased deep convective mixing, nutrient inputs and new production during the winter mixing period. It has been hypothesized that these events lead to enhanced NO3 input into the euphotic zone, followed by a rapid biological response and accumulation of biomass, and an equally rapid export of that biomass to the waters below. Direct observation and quantification of these potentially important nutrient injection events is challenging, however, an even greater challenge is understanding the mechanisms that link this nutrient input ultimately to carbon export.To expand the work of M.W. Lomas, et al. ("Enhanced New Production During Winter Mixing A Missing Component of Current Estimates"), researchers at the Woods Hole Oceanographic Institution and the Bermuda Biological Station for Research Inc. will add 3He Flux Gauge Techniques (FGT) measurements to the previously funded NSF project. The addition of FGT will enable the researchers to more accurately determine and quantify the important linkages between convective nutrient supply, biological response, and large-scale flux estimates specifically during the period of winter mixing when bi-weekly weather fronts pass through the Sargasso Sea. It is during this period that episodic nutrient inputs associated with deep convection are followed by short periods of stratification. The injected nutrients are rapidly consumed resulting in biomass accumulation, which is exported during the subsequent convective mixing event. The overall result is enhanced export production supported by short-lived, but quantitatively important nutrient injections. To enable the team of researchers to link the timing and magnitude of these fluxes and the ecological response, the researchers will use 3He (and 3He:NO3 ratios) as a tracer of these events. The information from this study will offer further insight into primary production and subsurface nutrient remineralization in oligotrophic systems, which are a central component of the ocean carbon-cycle and an important part of climate change modeling.

ABSTRACTOCE-0351651 / OCE 0351396最近的数据表明，在马尾藻海，每周的锋面移动会导致冬季混合期间深对流混合、养分输入和新产量增加。 据推测，这些事件导致进入富光区的 NO3 输入增加，随后发生快速的生物反应和生物量的积累，以及同样快速地将生物量输出到下面的水域。 直接观察和量化这些潜在重要的养分注入事件具有挑战性，然而，更大的挑战是了解将这种养分输入最终与碳输出联系起来的机制。 （“增强冬季新产量，混合当前估计中缺失的部分”），伍兹霍尔海洋研究所和百慕大生物研究站的研究人员将在之前资助的 NSF 项目中添加 3He 通量计技术 (FGT) 测量。 FGT的加入将使研究人员能够更准确地确定和量化对流养分供应、生物反应和大规模通量估计之间的重要联系，特别是在冬季混合期间，当每两周的天气锋面穿过马尾藻海时。 正是在这一时期，与深层对流相关的间歇性养分输入之后是短暂的分层。 注入的营养物质迅速消耗，导致生物量积累，并在随后的对流混合事件中输出。 总体结果是，在短期但数量上重要的营养物质注入的支持下，出口产量得到了提高。 为了使研究团队能够将这些通量的时间和强度与生态响应联系起来，研究人员将使用 3He（和 3He:NO3 比率）作为这些事件的示踪剂。 这项研究的信息将进一步深入了解寡营养系统中的初级生产和地下营养物再矿化，这是海洋碳循环的核心组成部分，也是气候变化模型的重要组成部分。