The Eel River Critical Zone Observatory: exploring how the critical zone will mediate watershed currencies and ecosystem response in a changing environment

鳗鱼河临界区观测站：探索临界区如何在不断变化的环境中调节流域货币和生态系统的反应令人惊讶的是，我们需要观察山坡内部，以了解大气湿度的变化，河流流量的大小和化学成分，生态系统的动态，甚至沿海海洋的生产力。这些联系出现在一个未被探索过的风化基岩的深层景观中，那里居住着微生物，位于山坡表面之下，在土壤地幔之下，在新的基岩边界之上。雨雪融化可以穿透风化的基岩，作为岩石水分保存下来，被树木利用，通过树叶的释放（蒸腾）将这些水分释放到大气中。基岩的特性会影响植物能获得多少水分，因此反过来又可能决定哪些物种能存活下来，尤其是在季节性干燥的环境中。树木释放的水分会影响空气湿度和温度，树木的类型会影响反射或吸收多少太阳能。这些反馈共同影响大气能量和环流（和动量）。雨雪融化也渗透到下面的新鲜基岩边界，在那里水栖息，并作为地下水流经风化基岩的溪流。这可以控制径流进入河流的时间、大小和化学性质，特别是在夏季低流量时期。因此，河流生态系统和沿海海洋（河流排放的地方）是来自山坡深处的水和营养物质的接受者。从植被冠层到土壤和风化基岩再到新基岩开始的整个区域被称为？临界区域。这个区域调节这些？分水岭货币?—水、沉积物、溶质（水中溶解的元素）、气体、生物体、能量和动量？它们在整个景观的生物和物理相互作用过程中交换和转化。PIs建议在北加州建立鳗鱼河临界区观测站，对控制这些货币的关键机制及其对水资源和生态系统可持续性的影响进行深入的实地调查。鳗鱼河CZO的科学家们将建立模型，探索这些货币如何在大气、山坡、河流和沿海海洋之间交换，以调查基本问题，并为管理问题提供指导。pi确定了四个关键的前沿问题：1)季节性干燥环境中的植物是否依赖于土壤下风化基岩的水分，如果是这样，基岩的特性如何影响这种可用性，从而影响植被对气候变化的适应能力？2)随着湿度条件的变化，临界区微生物如何影响山坡水化学和排放气体？3)在季节性干燥环境的排水渠道网络中，是什么控制着保持湿润的渠道（积水或流水）的空间范围？4)气候或土地利用变化引起的关键区域货币的变化是否会导致河流和沿海生态系统的突变？受到极端气候（特别是持续干旱）预期增加和社会对水需求加速的推动，pi专注于填补知识空白，这些空白不仅抑制了我们预测未来系统变化幅度的能力，甚至还抑制了这种变化的迹象。鳗鱼河CZO将在当地扎根于安杰洛海岸保护区（北加州），但将扩展到流域和区域尺度。它将致力于检测、解释和预测将分水岭货币与关键区域运行过程联系起来的驱动机制。我们还将开发一个模型，该模型将提供区域范围内的本地预测，可用于询问有关未来可能的气候和土地利用情景以及径流和生态系统条件的后果的“如果”问题。鳗鱼河CZO将培养一代学生和博士后，他们在气候科学、水文学、生态学、地球生物学、地球化学和地貌学等学科中共同努力，并在这些领域的界面上有所发现。将与其他czo有很强的相互作用。pi将积极与资源管理者和流域居民合作，分享和创造知识，并合作建立资源和生态系统的恢复能力，特别是在鳗鱼和俄罗斯河沿岸流域。他们将专注于这些流域，但预计我们的发现和建模将扩展到更广泛的地区。环境变化将会到来：对信息灵通的指导和工具的需求将会加速。只有通过耦合机制的实地研究和本文提出的综合建模，我们才能预测并为决策者提供工具，以指导景观及其生态系统功能和服务的未来状态

The Eel River Critical Zone Observatory: exploring how the critical zone will mediate watershed currencies and ecosystem response in a changing environmentSurprisingly, we need to look inside hillslopes to understand variations in atmospheric moisture, the magnitude and chemistry of river flows, the dynamics of ecosystems, and, even coastal ocean productivity. These connections arise in a deep, unexplored landscape of weathered bedrock, populated by microbes, that lies beneath the hillslope surface and below the soil mantle and above a fresh bedrock boundary. Rain and snow melt can penetrate this weathered bedrock, be held as rock moisture and be exploited by trees, which return this moisture to the atmosphere through release (transpiration) from leaves. Bedrock properties influence how much moisture is available to plants, so in turn may determine which species can persist, especially in seasonally dry environments. The water released by trees influences air humidity and temperature, and the tree type affects how much solar energy is reflected or absorbed. Collectively these feedbacks influence atmospheric energy and circulation (and momentum). Rain and snow melt also penetrate to the underlying fresh bedrock boundary where water perches and flows as groundwater to streams through the weathered bedrock. This can control the timing, magnitude, and chemistry of runoff to rivers, especially during summer low flow periods. Hence, river ecosystems and the coastal oceans (where rivers discharge) are recipients of water and nutrients derived from deep inside hillslopes. The entire zone from vegetation canopy down through the soil and weathered bedrock to the start of fresh bedrock is referred to as the ?critical zone.? This zone mediates these ?watershed currencies?-- water, sediment, solutes (dissolved elements in water), gases, organisms, energy and momentum?that are exchanged and transformed in the course of biological and physical interactions across landscapes. PIs propose to establish the Eel River Critical Zone Observatory in Northern California for intensive field investigations of key mechanisms controlling these currencies and their consequences for water resources and ecosystem sustainability. Eel River CZO scientists will build models to explore how these currencies are exchanged among atmosphere, hillslopes, rivers and coastal oceans to investigate fundamental questions and to provide guidance for management issues. PIs identify four key frontier questions: 1) Do plants in seasonally dry environments rely on moisture from the weathered bedrock beneath the soil and if so how might bedrock properties then affect this availability and thus the resilience of vegetation to climate change? 2) As moisture conditions change, how do microbes in the critical zone influence the water chemistry and gasses discharged from hillslopes? 3) What controls the spatial extent of channels that remain wet (standing or flowing water) in the network of channels draining seasonally dry environments? and 4) Will changes in critical zone currencies, induced by climate or land use change, lead to sudden shifts in river and coastal ecosystems? Motivated by anticipated increase in climate extremes (especially extended drought) and accelerating societal demand for water, PIs focus on filling knowledge gaps that not only inhibit our ability to forecast the magnitude of future change of systems, but even the sign of that change. The Eel River CZO will be locally rooted in the Angelo Coast Range Reserve (in Northern California), but will extend to watershed and regional scales. It will be dedicated to detecting, explaining, and predicting driving mechanisms that connect watershed currencies to processes that operate in the critical zone. We will also develop a model which will provide local predictions over a regional scale that can be used to ask "what if" questions about possible future climate and landuse scenarios, and the consequences for runoff and ecosystem conditions.The Eel River CZO will produce a generation of students and postdocs who have worked together across the disciplines of climate science, hydrology, ecology, geobiology, geochemistry and geomorphology and who have made discoveries at the interface of these fields. There will be strong interactions with other CZOs. PIs will actively work with resource managers and watershed residents to share and generate knowledge and collaborate to build resource and ecosystem resilience, specifically in the Eel and Russian River coastal watersheds. They will focus on these watersheds, but anticipate our findings and modeling will then be expanded to a much broader region. Environmental change will come: the need for well-informed guidance and tools will accelerate. It is only through coupling mechanistic field studies and integrated modeling as proposed here that we can forecast and offer tools for decision makers to guide the future state of landscapes and their ecosystem functions and services