Award: OCE-1821916

The breakout of the Southern California Thomas Fire in early December 2017 provided a unique opportunity to study the impact of dry ash deposition on the coastal ocean ecosystem. By leveraging a pre-planned student-led cruise aboard the RV Sally Ride, this RAPID award enabled an investigation that included measurements and experiments, with a value added tie to public engagement and outreach activities. The intellectual merit of these activities derived from the lack of understanding as to how ash deposition from wildfire might impact the coastal ocean. Research activities thus focused on identifying ash particles in sea water, surveying the affected waters, and amending surface seawater with ash to assess the impacts on primary production by phytoplankton and on respiration by bacteria. Ash in the coastal ocean exhibited complex behavior that seemingly included floatation, suspension, aggregation and sinking. Ash was also observed to yield a leachate – ash material that would gradually dissolve upon exposure to water. Through experimentation, ash and its leachate were found to have distinctive effects, notably leading to divergent bacterial community responses, providing nutrient available to feed primary production, and serving as a substrate for respiration by bacteria. These findings indicate that fire ash deposition holds the potential to impact base levels of the coastal ocean ecosystem through multiple mechanisms. The broader impacts of this work focused on enabling teams of graduate students to conduct research on fire ash deposition, providing support for key activities and analyses to enable their scientific development. This research has been translated to the public through a tie-in to a trio of artists who participated on the research expedition for the sole purpose of creating art from science. Products produced by the artists include a documentary, a music album, and numerous renderings that highlight research conducted under this award. The formalization of this integration between artistic and scientific activities is described in a published article. Last Modified: 05/08/2020 Submitted by: David L Valentine