Oceanic Efflux of Ancient Marine Dissolved Organic Carbon in Primary Marine Aerosol
Oceanic Efflux of Ancient Marine Dissolved Organic Carbon in Primary Marine Aerosol
Abstract:
Breaking waves produce bubble plumes that burst at the sea surface, injecting primary marine aerosol (PMA) highly enriched with marine organic carbon (OC) into the atmosphere. It is widely assumed this OC is modern, produced by present-day biological activity, even though nearly all marine OC is thousands of years old, produced by biological activity long ago. We used natural abundance radiocarbon (14C) measurements to show that 19 – 40% of the OC associated with freshly produced PMA was refractory dissolved organic carbon (RDOC). Globally, this process removes 2 – 20 Tg RDOC from the oceans annually, comparable to other RDOC losses. This process represents a significant removal pathway for old organic carbon from the sea, with important implications for oceanic and atmospheric biogeochemistry, the global carbon cycle, and climate.