Sycamore Creek Nutrient Injection Results - Raw, Phoenix Arizona, 2010 to 2013

The primary objective of this LTREB is to understand how long-term climate variability and change influence the structure and function of desert streams via effects on hydrologic disturbance regimes. Climate and hydrology are intimately linked in arid landscapes; for this reason, desert streams are particularly well suited for both observing and understanding the consequences of climate variability and directional change. Researchers try to (1) determine how climate variability and change over multiple years influence stream biogeomorphic structure (i.e., prevalence and persistence of wetland and gravel-bed ecosystem states) via their influence on factors that control vegetation biomass, and (2) compare interannual variability in within-year successional patterns in ecosystem processes and community structure of primary producers and consumers of two contrasting reach types (wetland and gravel-bed stream reaches). This specific dataset was collected to understand (1) how stream solute dynamics differs in wetland reaches and in gravel reaches, (2) how stream solute dynamics changes after winter flood; and (3) how stream solute dynamics differs in different years with different hydrological regimes.本LTREB项目的核心研究目标为：厘清长期气候变异性与气候变化如何通过作用于水文扰动格局，进而影响荒漠溪流的结构与功能。干旱景观中，气候与水文存在紧密的耦合关系；正因如此，荒漠溪流成为观测与解析气候变异性及方向性变化所产生影响的理想研究对象。研究团队将开展两项核心工作：其一，通过调控植被生物量的相关因子，明确多年尺度上的气候变异性与气候变化如何影响溪流的生物地貌结构（即湿地与砾石床生态系统状态的占比与存续性）；其二，对比两种典型河段类型（湿地河段与砾石床溪流河段）的初级生产者与消费者群落在生态系统过程及群落结构上的年内演替模式的年际变异性。本数据集的采集旨在回答三类科学问题：其一，湿地河段与砾石床河段的溪流溶质动态存在何种差异；其二，冬季洪水过后溪流溶质动态会发生怎样的变化；其三，在不同水文格局的年份中，溪流溶质动态存在哪些差异。