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Publication
The role of seabird guano in maintaining North Atlantic summertime productivity
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Advisor(s)
Abstract(s)
Nutrients supplied via seabird guano increase primary production in some coastal ecosystems. A similar process may
occur in the open ocean. To investigate this directly, we first measured bulk and leachable nutrient concentrations in
guano sampled in the North Atlantic. We found that guano was strongly enriched in phosphorus, which was released as
phosphate in solution. Nitrogen release was dominated by reduced forms (ammonium and urea) whilst release of nitrate was relatively low. A range of trace elements, including the micronutrient iron, were released. Using in-situ bioassays, we then showed that supply of fresh guano to ambient seawater increases phytoplankton biomass and
photochemical efficiencies. Based on these results, modelled seabird distributions, and known defecation rates, we estimate that on annual scales guano is a minor source of nutrients for the surface North Atlantic. However, on shorter
timescales in late spring/summer it could be much more important: Estimates of upper-level depositions of phosphorus
by seabirds were three orders of magnitude higher than modelled aerosol deposition and comparable to diffusion from
deeper waters.
Description
Keywords
Nutrients Iron Leaching experiment Phytoplankton Ocean fertilization Phosphate
Citation
Browning, T. J., Al-Hashem, A. A., Achterberg, E. P., Carvalho, P. C., Catry, P., Matthiopoulos, J., Miller, J. A. O., & Wakefield, E. D. (2023). The role of seabird guano in maintaining North Atlantic summertime productivity. Science of the Total Environment, 897. https://doi.org/10.1016/j.scitotenv.2023.165309
Publisher
Elsevier BV