Effects of African dust deposition on phytoplankton in the western tropical Atlantic Ocean off Barbados. Issue 5 (21st May 2016)

• Record Type: Journal Article
• Authors: Chien, Chia‐Te; Mackey, Katherine R. M.; Dutkiewicz, Stephanie; Mahowald, Natalie M.; Prospero, Joseph M.; Paytan, Adina
• Is Part Of: Global biogeochemical cycles. Volume 30:Issue 5(2016:May)
• Page Start: 716
• Page End: 734
• Publication Date: 2016-05-21
• Subjects: atmospheric deposition -- Barbados -- phytoplankton community structure -- nutrient limitation; Biogeochemical cycles -- Periodicals; Electronic journals; 577.1405
• DOI: 10.1002/2015GB005334
• Languages: English
• ISSNs: 0886-6236

Abstract

Abstract: Bioassay incubation experiments conducted with nutrients and local atmospheric aerosol amendments indicate that phosphorus (P) availability limited phytoplankton growth in the low‐nutrient low‐chlorophyll (LNLC) ocean off Barbados. Atmospheric deposition provides a relatively large influx of new nutrients and trace metals to the surface ocean in this region in comparison to other nutrient sources. However, the impact on native phytoplankton is muted due to the high ratio of nitrogen (N) to P (NO3 :SRP > 40) and the low P solubility of these aerosols. Atmospheric deposition induces P limitation in this LNLC region by adding more N and iron (Fe) relative to P. This favors the growth of Prochlorococcus, a genus characterized by low P requirements and highly efficient P acquisition mechanisms. A global three‐dimensional marine ecosystem model that includes species‐specific phytoplankton elemental quotas/stoichiometry and the atmospheric deposition of N, P, and Fe supports this conclusion. Future increases in aerosol N loading may therefore influence phytoplankton community structure in other LNLC areas, thereby affecting the biological pump and associated carbon sequestration. Key Points: Phytoplankton in low‐nutrient low‐chlorophyll waters near Barbados are phosphate limited Atmospheric deposition with high nitrogen and iron relative to phosphorus drives this phosphate limitation Prochlorococcus thrives in this environment due to its low phosphorus requirements