Moss Landing Marine Laboratories (MLML), located in central Monterey Bay, is part of the California State University system. With support from the Central and Northern California Ocean Observing System (CeNCOOS), MLML operates a shore station situated at the head of Monterey Canyon. Seawater pumped from an intake directly offshore in 17m of water is used in the labs for research and educational activities. A suite of sensors has been monitoring the physical and chemical properties of seawater at this location since 2010.
To gain a better understanding of regional carbonate chemistry, and to support research on the biological impacts of ocean acidification, MLML installed a Turner C-sense pCO2 sensor at this site. A month of preliminary data, collected during October 2016, shows strong fluctuations in temperature, pCO2, and pH. This site is known to be strongly influenced by large-amplitude internal waves, which are generated offshore by tidal currents flowing over steep topography and are then funneled through the canyon towards Moss Landing. Unlike surface waves, these internal waves are barely detectable at the sea surface, but they do have a strong effect on subsurface water properties, leading to strong fluctuations in pCO2 levels about twice per day. The colder water is characterized by high pCO2 due to microbial respiration below the euphotic zone, especially during times of the year when there is high productivity associated with coastal upwelling.
The data from this station will help MLML researchers better understand the physical and biological processes that influence the chemistry of seawater along the California coast. Monitoring the strong variability in seawater chemistry that occurs due to tidally-driven internal waves will allow for laboratory experiments that investigate a wide range of relevant oceanic conditions.
Author: Tom Connolly
Institution: Moss Landing Marine Laboratory
Monterey Bay, CA USA