Particles settling to the deep ocean remove carbon and essential trace elements for biological processes from the surface ocean and contact with the atmosphere over short time scales. Currently available technology is only able to resolve this flux at timescales of 24 hours to a few days and the methods are both labor- and time-intensive. Given the limited spatial and temporal scale of these flux measurements, it has been difficult to determine the processes that control the fate of particulate organic carbon (POC).
Scientists from Woods Hole Oceanographic Institution will use an optical, transmissometer-based method to obtain particle flux observations from autonomous, biogeochemical profiling floats. Initially, a laboratory-based sensor calibration experiment will be carried out to determine the detection limit of the system and evaluate its sensitivity to particle size. This will be followed by a field effort wherein data obtained from the floats will be compared against direct sampling from sediment traps. Lastly, the system will be deployed for about a year in the North Atlantic during which data will be returned via satellite from the biogeochemical float. This year long deployment will be the first of its kind to collect nearly-continuous, hourly-resolution proxy measurements of particle flux. The data is expected to yield new insights into the factors that influence variability in POC export. A potentially transformative aspect of this proposal will be the broad application of a newly developed method that cuts labor and ship costs while generating high resolution data.
Broader Impacts: Given the components for this system are readily commercially available means others in the science community have the opportunity to use this technology to make similar measurements. One postdoc would be supported and trained as part of this project. In addition, undergraduate students will be involved in the research via the Woods Hole Oceanographic Institution Summer Student Fellow and Minority Fellow program.
