A new water column profiler for shallow aquatic systems
Limnol. Oceanogr. Methods 3:190-202 (2005) | DOI: 10.4319/lom.2005.3.190
ABSTRACT: Coupled physical and biogeochemical processes in shallow (<2 m deep) productive systems must be observed on fine temporal and spatial scales with automated sampling and monitoring devices. We developed a pump profiler system that can sample six to eight depths at 10-cm resolution every 30 min. The system is economical, secure from vandalism, portable, and capable of integration with a real-time remote monitoring system. Solenoid valves select the suction depth, and a diaphragm pump delivers water to a flow cell where temperature, oxygen, pH, specific conductivity, turbidity, oxidation reduction potential, and fluorescence are measured with probes mounted on a water quality sonde. A microcontroller is used to direct the operation of the system. Water column disturbance and maintenance requirements are minimized by eliminating exposed moving parts. The data can be retrieved remotely and graphically displayed on the Internet in real time. The system has been deployed successfully in two freshwater ponds and a tidal saltwater system. The pump profiler is used to study coupled physical biogeochemical processes in shallow systems with strong diel cycles and large density and chemical gradients. Applications may include studies in aquaculture ponds, storm water retention ponds, shallow lakes, and small estuaries.