The NEREUS in-lake wireless/acoustic chemical data network

Abstract

We describe a system for the semi-autonomous in situ measurement of lake chemical properties, with high temporal resolution and the potential to map chemical properties in 3 dimensions. The system comprises both fixed sensor locations on moored buoys and one (or potentially more) autonomous underwater vehicles (AUVs) serving as mobile underwater sensor platforms. Sensors Include conventional water quality multiprobes and thermistor strings and the NEREUS underwater mass spectrometer for measurement of dissolved metabolic gases such as methane as well as permanent gases. Data are delivered to a shore station via a network that includes acoustic modems for communication with the AUV and a radio network operating in the license-free ISM (industrial, scientific, and medical) band operating under the IEEE 802.11b protocol. The system is designed to use low-cost commercial hardware and open-source software wherever possible. We constructed a prototype system of 3 buoys, 1 AUV, and a shore station, and field tests have demonstrated its ability to measure and remotely display lake chemical data in real time. © 2008, by the American Society of Limnology and Oceanography, Inc.