Lukas Taenzer, a recent Ph.D. graduate from the MIT-WHOI Joint Program, has been the lead on an important recent study. This study sheds light into the complex processes governing the continental shelf of the US Northeast. Published in the Journal of Geophysical Research: Oceans, the research focuses on the role of salinity in tracing changes within this vital coastal ecosystem. Taenzer and his research partner, Adrienne Silver, have leveraged a decade of historical data and state-of-the-art measurement technology. Together, they’ve revealed critical findings related to seasonal and interannual salinity changes in the Northwest Atlantic.
The study used a CTD rosette to profile important water characteristics in the southwestern Atlantic. This creative tool equipped researchers with the means to examine how salinity might contribute to stratification on the continental shelf. As they investigated further, they revealed its profound ecological consequences. To better understand what was happening, Tazcer and his team performed an extensive analysis to develop a salinity budget. This budget acts as a census taker, tracking how much ocean water is flowing in and out of the “cold pool,” which keeps these wintertime temperatures year-round—even in the steamy summer.
“This paper provides first evidence for a seasonal salinification of the cold pool on the US Northeast continental shelf, as consistently observed in the multi-year mooring record of the Ocean Observatories Initiative Coastal Pioneer Array,” Taenzer stated.
Our study demonstrates that salinity measurements can unique and powerful ways to capture the complexities of air-sea interactions. They continue to uncover how offshore forcing and upstream conditions drive coastal ecosystems. Taenzer noted, “We have known for a while that the cold pool changes throughout the year, and that it gets slightly warmer. What we didn’t know was why.” He explained that when you only look at temperature, you can’t identify the true drivers of these changes. “By tracking salt, we can actually pinpoint why the cold pool changes throughout the year,” he added.
The significance of this research goes beyond the ivory tower. Caroline Ummenhofer, senior scientist, Department of Physical Oceanography, WHOI. As someone who coordinates a related NASA project, she emphasized how quickly the fishing community has begun to integrate salinity measurements into their decision-making processes. “They are increasingly used by the fishing community, for example, in their decision-making,” she remarked.
This work incorporated recently available satellite sea surface salinity observations. In short, it used a lot of data like data from NASA’s Soil Moisture Active Passive satellite mission. This combination of advanced remote sensing technology helps shine light on salinity’s role as a stressor within this delicate coastal ecosystem.
Svenja Ryan, another researcher involved in the study, remarked on the importance of continuous subsurface measurements: “We didn’t see the salinification of the cold pool previously because we didn’t have continuous subsurface measurements.” She explained that measuring salinity instead of temperature provides a clearer picture of the health of coastal ecosystems.
Our findings highlight the need for routine salinity monitoring. They provide new insights into how air-sea interactions, offshore forcing, and upstream conditions interact to drive downstream impacts on coastal ecosystems in the sheltered cold pool over timescales of weeks to years. This knowledge is critical to enable NOAA Fisheries maximize the benefits of managing U.S. fish stocks sustainably,” Ryan added.
