Award: OCE-1459255

The ocean is difficult to study because most of it is far from land and the processes that go on in it, such as circulation, biological production and carbon cycling are complex and highly variable. As scientists, we would like to collect ocean data everywhere and all of the time but using ships is expensive; they cannot be operated year round, and they are hard to work on when the weather gets bad. Consquently, there is a great demand for autonomous measurement technology (sensors) that can be deployed to collect the data we need. This project is focused on the development of an autonomous alkalinity sensor. Alkalinity is an important parameter because it is part of the "inorganic carbon cycle" like CO2, that gives insights into the processes that control ocean pH and the side effects of anthropogenic CO2, that is, ocean acidification. Alkalinity is especially important for studying marine ecosystems where there are lots of organisms that form calcium carbonate shells or skeletons, like coral and some types of plankton. When calcium carbonate forms it removes carbonate from the water, which is one of the chemical species that contributes to alkalinity. Therefore, changes in alkalinity are a very sensitive indicator of the productivity of these organisms. The alkalinity sensor we have developed, named the Submersible Autonomous Moored Instrument for alkalinity, or SAMI-alk, can be put on a buoy or placed directly on the bottom to measure coral productivity. The SAMI-alk uses a novel method for measurement of alkalinity with a pH indicator that simplifies the laboratory method, making autonomous measurements possible. We have been testing the instrument both here in our lab at the University of Montana and with collaborators at Scripps Institution of Oceanography who have a seawater test tank facility. These tests have shown that the instrument accuracy and precision is very good, but that low temperatures can affect the measurements. We have been working on solving this problem; meanwhile we have been testing the instrument in a warm water environment, i.e. a coral reef in Bermuda. This 20-day experiment conducted in 2017 obtained excellent alkalinity data revealing the variability in the productivity of the reef. The SAMI-alk has subsequently been commercialized. With the SAMI-alk available to other researchers, we can accelerate our understanding of the processes that control coral and plankton productivity thereby making it possible to more accurately predict the future health of these vital organisms. This is an important broader impact resulting from this grant. Last Modified: 08/30/2019 Submitted by: Michael Degrandpre