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Ocean urea fertilization for carbon credits poses high ecological risks


Glibert, PM and Azanza, R and Burford, M and Furuya, K and Abal, E and Al-Azri, A and Al-Yamani, F and Andersen, P and Anderson, DM and Beardall, J and Berg, GM and Brand, L and Bronk, D and Brookes, J and Burkholder, JM and Cembella, A and Cochlan, WP and Collier, JL and Collos, Y and Diaz, R and Doblin, M and Drennen, T and Dyhrman, S and Fukuyo, Y and Furnas, M and Galloway, J and Graneli, E and Ha, DV and Hallegraeff, GM and Harrison, J and Harrison, PJ and Heil, CA and Heimann, K and Howarth, R and Jauzein, C and Kana, AA and Kana, TM and Kim, H and Kudela, R and Legrand, C and Mallin, M and Mulholland, M and Murray, S and O'Neil, J and Pitcher, G and Qi, YZ and Rabalais, N and Raine, R and Seitzinger, S and Salomon, PS and Solomon, C and Stoecker, DK and Usup, G and Wilson, J and Yin, KD and Zhou, MJ and Zhu, MY, Ocean urea fertilization for carbon credits poses high ecological risks, Marine Pollution Bulletin, 56, (6) pp. 1049-1056. ISSN 0025-326X (2008) [Refereed Article]

DOI: doi:10.1016/j.marpolbul.2008.03.010


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.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Phycology (incl. marine grasses)
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Adaptation to climate change
Objective Field:Climate change adaptation measures (excl. ecosystem)
UTAS Author:Hallegraeff, GM (Professor Gustaaf Hallegraeff)
ID Code:55362
Year Published:2008
Web of Science® Times Cited:36
Deposited By:Plant Science
Deposited On:2009-03-10
Last Modified:2009-06-03

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