Cutting edge environmental monitoring comes to New Hampshire

Sensors have become an integral part of our daily lives, from thermometers to networks of wireless humidity sensors used to monitor fire danger in remote forests.  Sensor technology is advancing rapidly, becoming easier to use and to maintain, allowing us to push the boundaries of scientific research.  Recently, this has become international news with the sensor technology on the Rover now deployed on the surface of Mars.  This technology is advancing rapidly in the ecological sciences and is now allowing us to measure parameters in soils and rivers as accurately as we can in the laboratory.  At the same time, the technology for wireless communications and solar power has also advanced and become more affordable enabling us to connect sensors directly to our research labs and monitor the environment in remote areas in real-time.

One of the key ecological questions facing New Hampshire is, "What impacts are land use and climate change having on ecosystems throughout the state?"  To help answer this, we have been developing and maintaining a state-wide network of soil and water sensors as part of the New Hampshire EPSCoR program.  The sensors network will be capable of delivering fine time scale data, which will enable a better linkage between responses in headwater systems and the impacts on the larger river drainage networks.  It is our aim to link soil processes to water chemistry parameters by co-locating terrestrial and aquatic sensor sites wherever possible.  The data we gather will provide modelers with resources needed to develop scenarios for future change, which can be used by teachers, interested citizens, or environmental managers wanting to learn more about watershed systems in New Hampshire.

A sensor network is designed to transmit the data from an array of sensors to a data repository on a computer server.  In the case of both our soil and aquatic sensor networks, various sensor nodes are deployed and are connected to a datalogger that stores the data and is programmed to tell the sensors when to collect data.  This system is powered either by hard-wired electricity or by batteries that are charged by solar panels.  The data is then transmitted by cell phone modems back to NH EPSCoR’s data server.

Soils Sensors 

With our complex soil sensor system, we have an array of sensors that examines how soil properties and processes change as climate in the region changes by monitoring soil carbon (C) at multiple sites across the state. At each one of our sites we have six chambers which automatically detect the CO₂ being respired by soil microbes using an infrared gas analyzer.  Paired with each chamber we have three soil sensors installed at the soil surface and fifteen and thirty centimeters below the surface, which detect temperature, moisture content and electrical conductivity.  We collect basic weather data at each site as well, such as air temperature and precipitation amounts.  By understanding how extreme weather events affect soil properties and processes as well as stream chemistry, we can predict the likely effects of climate change on soils and water quality in the coming decades. 

Aquatic Sensors

The aquatic side of the sensors network is comprised of two main instruments: (1) The EXO2 by YSI is a multi-parameter water chemistry instrument, with interchangeable sensors capable of measuring pH, temperature, dissolved oxygen, conductivity, turbidity, fluorescent dissolved organic matter (fDOM – a surrogate for dissolved organic carbon), and (2) the Specific Ultra-Violet Nitrate Analyzer (SUNA) by Satlantic, which measures nitrate concentration.  We are also collecting river flow data to help determine patterns with weather events and climate change. The sensors sample the selected stream and river sites every 15 minutes. Data on this time scale will give researchers a detailed look into how streams respond to differing types of land use or management, as well as changes with storm events.

EXO2 multi-parameter sonde, by YSI

Specific Ultra-Violet Nitrate Analyzer (SUNA), by Satlantic

Sensor and communication technology has advanced rapidly in this field, where this kind of work could not have been done this way 10 years ago. In the case of one of the sensors, the SUNA can detect nitrate almost as low as we can back in the lab and is a significant advancement from previous sensors that had detection limits several times higher. It is also relatively maintenance free. A wiper keeps things from collecting in the sample path and a copper guard keeps microbes in check. The wireless communications are so good that we now can communicate with all of our sensors even in remote areas of the White Mountains. This is an exciting time in our field and the quantity and quality of the data we produce will help push our understanding of our environment. In our next post we’ll let you know what the challenges we face when installing the sensors.

   

Sensors suite ready for deployment

Posted by Jody Potter, Analytical Instrumentation Scientist III; Brian Godbois, Senior Laboratory Technician; Lisle Snyder, Laboratory Technician II
Natural Resources & the Environment, University of New Hampshire