Taking the pulse of nature – How robotics and sensors assist in lake and reservoir management

Abstract. Ecosystems, like almost any environmental entity, are often highly sensitive to the presence of humans when measuring field characteristics. Robotic solutions deserve attention to avoid or greatly reduce related bias. Constant availability of robotic solutions, independent of the time of day and most weather conditions, is an additional advantage. Here, we present an autonomous, Modular Aquatic Robotic Platform (MARP-FG) designed to collect relevant environmental information from surface waters. We define the demands, describe the encountered obstacles and how to overcome them. MARP-FG implements autonomous navigation and data collection capability across various floating-body configurations and sensor setups. Depending on the weight of the measurement system (payload), catamaran floaters with a length ranging from 1.2 meters to 2.5 meters are used. We realized and evaluated three different payloads based on the MARP-FG concept: i) Hydrographic profiling with a multi-parameter probe, ii) Sonar-based 3D mapping of complex basins, and iii) Dynamic closed chamber-based greenhouse gas exchange determination with on-board CO2 quantification (IR spectrometry) and gas sampling (Exetainers®) for subsequent gas-chromatographic analysis. This work focuses on option iii) as a practical example to describe our design process and operational modes, thus minimizing faults and errors, especially in harsh environments. Full operation was possible to wave heights of ±40 cm and wind speeds to 7 m sec-1. Positioning accuracy during measurement cycles was on average better than ±2 m in xy directions. The platform has demonstrated its capabilities in field campaigns on lakes in the Amazon basin (Brazil) and on waterbodies in temperate climate regions of Europe. Largely improved and reproducible positioning on a waterbody, full functionality also under adverse weather conditions and during nighttime significantly enhanced high-quality data acquisition and opens new applications.