Environmental sensor networks capable of taking data quickly enough to capture minute-scale fluctuations and durable enough to capture these data for entire seasons provide essential information for studying the seasonal and annual effects of environmental activity across complete ecosystems. The models informed by this data are useful for predicting both short- and long-term changes to economically important coastal ecosystems. Distributed sensors for dissolved oxygen (DO) concentration measurement in coastal marine settings are of particular interest because of the important role DO plays in catalyzing a diversity of environmentally important biogeochemical reactions. However, commercially available DO sensors are not suited for long-term or in situ measurements in marine environments. The overall goal of this research plan is to explore the feasibility of long-term and in situ deployment of DO sensors in a marine environment. In the first phase of this work, a novel DO sensing technology will be coupled with a remote power and data-logging system to explore the feasibility of remote in situ DO measurement. Additionally, long-term DO sensor stability in the challenging marine environment will be characterized. In the second phase of this work the technology will be developed further, leading to the establishment of a cost-effective remote DO sensing array capable of ecosystem-scale measurements at the important coastal/terrestrial interface. Commercial Applications and Other Benefits DO measurements provide critical information for many areas, including water-quality assessment, groundwater contamination modeling, industrial-process control, and the management of fisheries. Improvements in DO sensing technology that improve performance and reduce cost will benefit these areas directly. These technological developments will also enable the deployment of marine ecosystem-scale DO sensing networks that will provide information critical to the improvement of predictive ecosystem models. These ecosystem models guide our efforts to protect economically important coastal marine ecosystems.