Cycling of ethanol and acetaldehyde in coastal waters

The short-term goal of this work is to improve our understanding of ethanol and acetaldehyde cycling in coastal waters. Increased use of ethanol as a fossil fuel substitute and additive is expected to have an impact on atmospheric levels of both ethanol and acetaldehyde. To understand future impacts, we need to understand current tropospheric budgets. One of the largest sources of uncertainty in budget estimates is the role of the oceans and surface waters in cycling these species into or out of the troposphere. Concentrations of ethanol and acetaldehyde in water are controlled primarily by biological degradation and photochemical production. Measurements of these production and destruction rates will help constrain estimates of air-water exchange of these species. Here we report measurements of ethanol and acetaldehyde biological degradation rates, and photochemical production rates at three sites in a classic Southern Californian estuary. We also report measurements of a dark ethanol to acetaldehyde biological conversion process.