Deep sea

Composite number

Organic matter

Ecology

Biology

Carbon cycle

Materials science

Carbon fibers

Geology

Oceanography

Sea surface temperature

Organic chemistry

Total organic carbon

Environmental chemistry

Water column

Abyssal zone

Environmental science

Seabed

Composite material

Deep ocean water

Chemistry

Atmospheric sciences

Flux (metallurgy)

Carbon dioxide

Sediment trap

Carbon sequestration

Ecosystem

Proceedings of the National Academy of Sciences

Significance Ignoring temporal fluctuations in the oceanic carbon budget leads to a significant misrepresentation of the cycling of organic matter from production in surface waters to consumption and sequestration in the abyssal ocean. A 29-year time series (1989 to 2017) of particulate organic carbon (POC) fluxes and sea-floor measurements of sediment community oxygen consumption (SCOC) revealed episodic, high-magnitude events over the past 7 years. Time lags between changes in satellite-estimated export flux, POC flux and SCOC varied from 0 to 70 days. A commonly used model to estimate carbon flux through the water column significantly underestimated the measured carbon fluxes by almost 50%. Episodic pulses of organic carbon into the deep sea must be accounted for to balance the oceanic carbon budget.

Episodic organic carbon fluxes from surface ocean to abyssal depths during long-term monitoring in NE Pacific