PNNL

Abstract

Interconnected landscape features such as terrestrial-aquatic interfaces play an outsized role in biogeochemical cycles as ecosystem control points but are notoriously challenging to characterize. Here we document a synoptic sensor network design that is 1) flexible to accommodate diverse ecosystem interfaces and gradients, 2) adaptable to monitoring and modeling needs of small and large projects alike, and 3) standardized for inter-comparability across sites and field experiments. This real-time monitoring of surface water, groundwater, soil, and vegetation supports configuration and evaluation models that span upland, wetland, open water strata, and transitions between them. Sensors were deployed at hypothesized permanent control points relevant to site- and global-scale models, with high temporal resolution to capture activated control points. We deployed this network design at seven sites along the Chesapeake Bay and Lake Erie coastlines and an ecosystem-scale flooding experiment. A central design element is “one data logger program to rule them all”—a collection of sensor-specific modules deployed on 27 loggers controlling 541 sensors, with the goal of streamlining maintenance, debugging, and reproducible data processing. The network generates ~3M observations per month, capturing system dynamics at the broad spatial and fine temporal scales needed to initialize and benchmark models; measurement frequency can be modified remotely to capture events. This network design has also revealed behaviors not represented in Earth system models, such as transient groundwater oxygen pulses. Completely documented and open source, this standardized, flexible, and efficient sensor network design can reduce barriers to understanding environmental changes and ecosystem responses across systems and scales.