Ocean urea fertilization for carbon credits poses high ecological risks

Patricia M. Glibert, Rhodora V. Azanza, Michele Astrid Burford, Ken Furuya, Eva G. Abal, Adnan R.N. Al-Azri, Faiza Aa Al-Yamani, Per Kragh Andersen, Donald M. Anderson, John Beardall, Gry Miné Berg, Larry E. Brand, Deborah A. Bronk, Justin D. Brookes, Jo Ann Burkholder, Allan D. Cembella, William P. Cochlan, Jackie L. Collier, Yves Collos, Robert J. DiazMartina A. Doblin, Thomas E. Drennen, Sonya T. Dyhrman, Yasuwo Fukuyo, Miles J. Furnas, James N. Galloway, Edna Granéli, Dao Viet Ha, G. M. Hallegraeff, John A. Harrison, Paul J. Harrison, Cynthia A. Heil, Kirsten Ruth Heimann, Robert W. Howarth, Cécile Jauzein, Austin A. Kana, Todd M. Kana, Hakgyoon Kim, Raphael M. Kudela, Catherine Legrand, Michael A. Mallin, Margaret R. Mulholland, Shauna A. Murray, Judith M. O'Neil, Grant C. Pitcher, Yuzao Qi, Nancy N. Rabalais, Robin C.T. Raine, Sybil Putnam Seitzinger, Paulo Sergio Salomon, Caroline M. Solomon, Diane K. Stoecker, Gires Usup, Joanne R. Wilson, Kedong Yin, Mingjiang Zhou, Mingyuan Zhu

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.
Original languageEnglish
Pages (from-to)1049-1056
Number of pages8
JournalMarine Pollution Bulletin
Issue number6
Publication statusPublished - 2008


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