English: Simplified budget of carbon flows in the ocean
Each year net phytoplankton production is about 50 Pg C (1 Pg = 1 Gt = 1015 g), 10 Pg is exported to the ocean interior, the other 40 Pg is respired in the euphotic zone. Organic carbon degradation continues while particles settle through the ocean interior and only 2 Pg eventually arrives at the seafloor, the other 8 Pg is respired in the dark ocean. In sediments, the time scale available for degradation increases order of magnitude with the result that 90% of the organic carbon delivered is degraded and only 0.2 Pg C yr⁻¹ is eventually buried and transferred from the biosphere to the geosphere.