Finding Answers Blowing in the Wind

On a windy day, Melf Paulsen (right) a graduate student working with Christa Marandino at GEOMAR, and Austin McHugh (left), UNOLS relief marine technician, install components of Damian Grundle’s new eddy covariance package on the mast of the BIOS-operated vessel Atlantic Explorer. Field trials in June were successful, Grundle said. “The next big step is to develop routines for analyzing the data,” he said.

The research vessel Atlantic Explorer sailed from BIOS in June sporting a new instrument package on its mast and bow designed to measure climate-relevant, constantly shifting gases, moisture, and heat between the ocean and the atmosphere.

The instrument package, called an eddy covariance system, will be used routinely during regular cruises to the Bermuda Atlantic Time-series Study (BATS) site and other regions of the Sargasso Sea, adding to a wealth of information collected over years and decades on fundamental ocean processes and functions. Measuring gases exchanged between the ocean and atmosphere helps scientists understand Earth’s natural processes and is critical for predicting potential future climate changes, said BIOS chemical oceanographer Damian Grundle, the lead on the new project.

In January, Grundle was chosen from six applicants within BIOS to receive support from the Institute’s recently established Cawthorn Innovation Fund to develop the instrument package for use on the Atlantic Explorer.

“For a number of years now I have been interested in how atmospherically relevant gases are produced and consumed via biological processes in the ocean,” he said. While understanding the biological cycling of dissolved gases in the ocean is extremely important, it is equally necessary to understand how gases are exchanged between the atmosphere and the ocean.

The Cawthorn Innovation Fund provided the resources to expand his research and increase the capabilities of his lab, he said, as well as increase the capacity for additional atmospheric work to be conducted onboard the Atlantic Explorer. In his proposal, Grundle wrote that, in recent years, a great deal of work has gone into understanding the oceanic production and consumption of a number of important atmospheric gases.

“While this work has provided important insights into how the ocean may act as a source or sink of these gases, our understanding of air-sea gas fluxes and the factors that impact them needs improving,” he said. Examples of such gases include carbon dioxide, nitrous oxide, and dimethylsulfide, or DMS, which represents a large source of sulfur going into Earth’s atmosphere.

The instrument package is designed to measure air-sea exchange of carbon dioxide, but the addition of other analyzers will allow it to measure the exchange of other gases. The package comprises a number of components, including sensors mounted at the top of the forward mast for logging the position of the ship, as well as for measuring wind speed and the motion of the ship. An inlet on the mast allows atmospheric air to be pumped into a dedicated laboratory van at the front of the ship, where an analyzer measures the carbon dioxide content of the air and additional data loggers record the results obtained from the analyzer and mast-based sensors.