Waves breaking and bubbles popping at the Earth’s surface eject seawater droplets into the atmosphere 10’s of nanometers to 100’s of micrometers in diameter, called sea spray aerosol (SSA). These aerosols are tiny subsamples of the ocean’s surface, and the ocean has high numbers of heterotrophic bacteria,more than a million per milliliter, in addition to phytoplankton, zooplankton,viruses (10 million viruses per milliliter), and other microorganisms. Heterotrophic bacteria cover themselves and release into the seawater enzymes that clip off small molecules from complex marine organic material that the bacteria can ingest as food. In the process, enzymes shape seawater composition and thereby can affect the makeup of the particles being produced. Research led by Francesca Malfatti* has recently discovered viable enzymes in SSA, which can change particle composition in the atmosphere. (*Istituto Nazionale di Oceanografia e di Geofisica Sperimentale & Scripps Institution of Oceanography, UC San Diego)
At Scripps Institution of Oceanography (UniversityCalifornia San Diego), the Liquid SpotSampler™ particle collector has been employed to detect enzymes in aerosol along California. Sampling was conducted on the Scripps Oceanography pier, targeting sea spray aerosol produced in the surfzone, beginning in the summer of 2017. The new year brought a new opportunity and the Spot Sampler was taken aboard one of the newest and most advanced research vessels in the world: the RV Sally Ride, named after the first woman in space from the USA, and former UC San Diego professor[i].
The Spot Sampler collected particle samples as the ship travelled along the California coast from San Diego to offshore of Central California. The samples were immediately analyzed on board for enzyme activities. Conditions were almost ideal: whitecaps and breaking waves were present as a source of fresh SSA without conditions getting too rough to sample on deck. With the Spot Sampler’s high collection efficiency and sampling-into-liquid capabilities, the research aboard aims to gain insight into which enzymes transfer from the ocean to the atmosphere.
