Dissolved Organic Matter

Most Dissolved Organic Matter (DOM) released by phytoplankton is quickly degraded by heterotrophs within hours to days. As a result, the majority of DOM that is found in the ocean has a lifetime (determined via 14C-carbon dating) of over 16,000 years.

References

Dittmar, T., Lennartz, S.T., Buck-Wiese, H. et al. Enigmatic persistence of dissolved organic matter in the ocean. Nat Rev Earth Environ 2, 570–583 (2021). https://doi.org/10.1038/s43017-021-00183-7