Collaborative Research: MRA: Particulates in canopy flowpaths: A missing mass flux at the macrosystem scale?

合作研究：MRA：冠层流动路径中的颗粒物：宏观系统尺度上缺失的质量通量？

• 批准号: 2213623
• 负责人: John Van Stan
• 金额: $ 224.28万
• 依托单位: Cleveland State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2213623&HistoricalAwards=false
• 关键词: Collaborative; Research; MRA; Particulates; canopy

Forests cover one-third of the land on Earth. For rainfall to pass through the forest canopy, it must drain along two “hydrologic highways”: throughfall (water that drips through gaps and from leaves or bark); and stemflow (water that runs down stems). As throughfall and stemflow drain, they wash particles from leaves and bark. Although tiny, particles washed from the canopy by these hydrologic highways can constitute a significant chemical input to the soil, and represent a wide range of materials, from nutrients to pollutants. Despite this, no large-scale effort has sought to measure, scale, and predict the amount and quality of particles descending down these hydrologic highways. These particles are generally “missing” from current ecological theory of how forests cycle elements. This study seeks to fill this gap by monitoring storm conditions, throughfall, stemflow, and the particles in these hydrologic highways across sites representing major forest types in North America. Results will link throughfall and stemflow to common models used to inform freshwater and forest management. Outcomes will inform outreach efforts, including science comics and illustration exhibits, open-access articles written for (and reviewed by) primary and secondary school children with Frontiers for Young Minds, and YouTube videos with MinuteEarth, a channel with an international viewership of millions. The project will also provide research experiences to members of underrepresented groups to broaden participation in science.For 40% of the North American continent and one-third of global land surface, rainfall must pass through forests to reach the soil surface. This rainfall is partitioned by the forest canopy into two net rainfall fluxes: a drip flux called throughfall (TF), and a flow of water down stems, called stemflow (SF). How much rain travels along these hydrologic highways can alter water supply by 20-50%, and what they carry from the canopy can supply 100 kg per hectare of various materials to the soil surface each year. These canopy ecohydrological processes are on the front line of climate and land use change, being that the forest-rainfall interactions that initiate terrestrial hydrological pathways and supply nutrients/pollutants to the surface are the first ecosystem elements impacted by hydrologic intensification. Ignoring these fluxes, and their particulate traffic, introduces error in water and nutrient flux models at the first point where terrestrial biogeochemistry and hydrological cycles entwine, and which may cascade those errors through downgradient processes. This project aims to extend current macrosystem biological understanding to include throughfall and stemflow particulate concentrations, fluxes and composition, specifically addressing 3 major objectives: (1) estimate the net rainfall (TF+SF) water and particulate mass flux across forest types; (2) characterize the particulate composition (C:N:P, including C components like total C, organic C, black C, and microplastic C) of TF and SF; and (3) identify major drivers of macrosystem variability in net rainfall particulate flux and composition. Field monitoring of the above variables across 11 sites of the National Ecological Observatory Network representing the major US forest domains allows links to be tested between existing functional characteristics and the practical integration of throughfall and stemflow dynamics into continental-to-global scale biogeophysical models. The project will also support research training of a postdoctoral researcher, masters and doctoral students, and a technician.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.

森林覆盖了地球上三分之一的土地，降雨必须沿着两条“水文高速公路”排出：径流（从树叶或树皮滴下的水）和茎流（流动的水）。作为径流和茎流排水，它们从树叶和树皮上冲走颗粒，尽管这些水文高速公路从树冠上冲走的颗粒可以构成对土壤的重要化学输入，并代表多种来自养分的物质。到尽管如此，目前还没有大规模的努力来测量、衡量和预测沿着这些水文高速公路下降的颗粒物的数量和质量，这些颗粒物在当前的森林元素循环生态理论中通常是“缺失的”。旨在通过监测代表北美主要森林类型的地点的风暴状况、径流、茎流和颗粒物来填补这一空白，结果将把径流和茎流与用于通知淡水和森林管理的通用模型联系起来。通知外展该项目还将为代表性不足群体的成员提供研究经验，以扩大对科学的参与。对于北美大陆的 40% 和全球陆地表面的三分之一，降雨必须穿过森林才能到达土壤表面。这种降雨是分开的。由森林冠层进入两个净降雨通量：称为径流 (TF) 的滴水通量，以及称为茎流 (SF) 的水流。沿着这些水文高速公路的降雨量可以改变 20-50% 的供水量及其携带的水量。树冠每年可以向土壤表面提供每公顷 100 公斤的各种物质，这些树冠生态水文过程处于气候和土地利用变化的最前沿，是引发森林-降雨相互作用的原因。陆地水文路径和向地表供应营养物/污染物是受水文强化影响的第一个生态系统要素，忽略这些通量及其颗粒物流量，会在陆地生物地球化学和水文循环交织的第一个点上引入水和营养物通量模型的误差，该项目旨在扩展当前的宏观系统生物学理解，以包括径流和茎流颗粒浓度、通量。和成分，具体涉及 3 个主要目标：(1) 估计整个森林类型的净降雨量 (TF+SF) 水和颗粒物质量通量；(2) 表征颗粒物成分 (C:N:P，包括总碳等碳成分)； 、有机 C、黑色 C 和微塑料 C) 的 TF 和 SF；以及 (3) 确定净降雨颗粒通量和成分宏观系统变化的主要驱动因素，对代表国家生态观测站网络的 11 个站点的上述变量进行现场监测。美国主要森林领域可以测试现有功能特征与将穿流和茎流动力学实际整合到大陆到全球范围的生物地球物理模型之间的联系，该项目还将支持博士后研究员、硕士和博士生以及技术人员的研究培训。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。