Seagrass ecosystems, including associated micro- and macro-algae and bacteria, are productive ecosystems with high O2 production, rapid nutrient cycling, and efficient carbon burial. Photosynthesis and respiration rates within seagrass systems have historically focused on measuring O2 fluxes. Recently, however, the production of reactive oxygen species (ROS) by microorganisms was identified as a quantitatively important sink for oxygen in the ocean - a process that is not taken into account in current oxygen flux measurements. In addition to microorganisms, seagrass and macroalgae have been shown to produce extracellular ROS, yet the impact of this production on oxygen fluxes has not been investigated. In this study, we identified and quantified the contribution of the ROS hydrogen peroxide on O2 levels within temperate seagrass ecosystems within Woods Hole, MA. Over the course of a summer, we measured hydrogen peroxide production and decay rates, as well as decay pathways associated with seagrass, algae, and sargassum within seagrass beds. In this presentation, we will discuss the range of production and decay rates observed and the fate of hydrogen peroxide, which leads to either net oxygen loss or recycling. Overall, these results highlight the complexity of organisms and processes controlling the oxygen cycle and the need to better constrain the role of ROS on the global marine oxygen budget.

Reevaluating the oxygen cycle within seagrass ecosystems from the viewpoint of reactive oxygen species

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.