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、河流流量的大小和化学成分、生态系统的动态，甚至沿海海洋生产力的变化。这些联系出现在一片深厚的、未被勘探的风化基岩景观中，微生物聚集在山坡表面之下、土壤地幔之下和新的基岩边界之上。雨雪融化可以穿透这块风化的基岩，以岩石水分的形式被树木利用，树木通过树叶的释放(蒸腾)将这些水分返回到大气中。基岩的性质影响植物可获得多少水分，因此反过来可能决定哪些物种能够持续存在，特别是在季节性干燥的环境中。树木释放的水分影响空气湿度和温度，树木类型影响太阳能被反射或吸收的程度。总体而言，这些反馈影响大气能量和环流(以及动量)。雨雪融化还渗透到下面的新鲜基岩边界，那里的水栖息并随着地下水流入穿过风化基岩的溪流。这可以控制流向河流的径流的时间、大小和化学成分，特别是在夏季枯水期。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。从植被覆盖穿过土壤和风化基岩到新基岩开始的整个地带被称为临界区。这一区域调节着这些分水岭货币--水、沉积物、溶质(水中溶解的元素)、气体、生物、能量和动量--在整个景观的生物和物理相互作用过程中交换和转化。PIS提议在加利福尼亚州北部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兑换，以调查基本问题，并为管理问题提供指导。PIS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土壤下风化基岩的水分，如果是这样，基岩的性质将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，临界区的微生物如何影响从山坡排放的水化学和气体？3)是什么控制着渠道网络中保持湿润(静止或流动的水)的渠道的空间范围？4)气候或土地利用变化引起的临界区货币变化是否会导致河流和沿海生态系统的突然变化？在极端气候(特别是长期干旱)预期增加和社会对水的需求加速的推动下，PIs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，甚至抑制了这种变化的迹象。Eel River CZO将植根于安吉洛海岸山脉保护区(位于加利福尼亚州北部)，但将延伸到分水岭和区域规模。它将致力于检测、解释和预测将分水岭货币与在临界区运行的过程联系起来的驱动机制。我们还将开发一个模型，它将提供区域范围内的局部预测，可以用来询问关于未来可能出现的气候和土地利用情景，以及对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工作，并在这些领域的交界处取得发现。与其他CZO将会有很强的互动。PIS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复原力，特别是在鳗鱼和俄罗斯河沿岸流域。他们将专注于这些分水岭，但预计我们的发现和建模将扩展到更广泛的区域。环境变化将会到来：对知情指导和工具的需求将会加快。只有将机械实地研究和集成建模相结合，才能为决策者提供预测和指导未来景观状态及其生态系统功能和服务的工具

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