On the role of physical processes on the surface chlorophyll variability in the Northern Mozambique Channel

  • Avelino A. A. LangaEmail author
  • Paulo H. R. CalilEmail author
Part of the following topical collections:
  1. Topical Collection on the 10th International Workshop on Modeling the Ocean (IWMO), Santos, Brazil, 25-28 June 2018


In the Indian Ocean regions under the influence of monsoons, two phytoplankton blooms characterize the seasonal cycle of surface chlorophyll, one during summer, and the other during winter. In the Northern Mozambique Channel, however, where the wind regime is an extension of the northern Indian Ocean monsoons, the annual cycle of chlorophyll concentrations is characterized by a single winter bloom. Wind stress and surface net heat flux modulate the seasonal cycle of the mixed layer depth with impacts on the surface chlorophyll. In order to evaluate the importance of these forcing fields on the seasonality of the mixed layer depth, and consequently, the surface chlorophyll variability, we used a suite of physical-biogeochemical model sensitivity experiments. Our results show that the seasonal cycle of surface chlorophyll is primarily modulated by the net heat flux while the wind field controls the amplitude. The winter bloom is triggered by negative surface heat fluxes, where cooling at the surface induces mixing and entrainment of nutrients at the base of the nutricline and light is not limiting. Winds enhance the winter bloom by uplifting additional nutrients and diluting subsurface chlorophyll into the surface layer. In the summertime, weaker wind stress and positive heat flux inhibit vertical mixing. As a consequence, the surface layer is depleted in nutrients and a deep chlorophyll maximum is formed. Analysis of top-down control on phytoplankton biomass reveals that zooplankton abundance increases in a near-linear proportion with phytoplankton biomass despite the deepening of the mixed layer depth. This suggests that the phytoplankton stock in the Northern Mozambique Channel is also controlled by grazing, given that zooplankton biomass is not directly affected by the deepening of the mixed layer during wintertime.


Wind stress Surface net heat flux Mixed layer depth Deep chlorophyll maximum Surface chlorophyll Mozambique Channel 



The first author thanks Rodrigo Mogollón for his useful suggestions.

Funding information

This work was financially supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Programa de Pós-graduação Ciência para o Desenvolvimento (CAPES-PGCD) scholarship, which is a collaboration between Ministério da Educação, Brazil and Programa de Pós-graduação Ciência para o Desenvolvimento (PGCD), Instituto Gulbenkian de Ciência, Oeiras, Portugal. PHRC acknowledges support from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil, Bolsa de Produtividade em Pesquisa (Process 306971/2016-0).


  1. Aumont O, Bopp L (2006) Globalizing results from ocean in situ iron fertilization studies. Glob Biogeochem Cycles 20(2). CrossRefGoogle Scholar
  2. Aumont O, Maier-Reimer E, Blain S, Monfray P (2003) An ecosystem model of the global ocean including fe, si, p colimitations. Glob Biogeochem Cycles 17(2). CrossRefGoogle Scholar
  3. Backeberg B, Reason C (2010) A connection between the south equatorial current north of Madagascar and Mozambique channel eddies. Geophys Res Lett 37(4).
  4. Banse K, English D (2000) Geographical differences in seasonality of CZCS-derived phytoplankton pigment in the Arabian Sea for 1978–1986. Deep-Sea Res II Top Stud Oceanogr 47(7):1623–1677. CrossRefGoogle Scholar
  5. Boyer Montégut C, Mignot J, Lazar A, Cravatte S (2006) Control of salinity on the mixed layer depth in the world ocean. In: AGU Fall Meeting AbstractsGoogle Scholar
  6. Calil P, Richards K (2010) Transient upwelling hot spots in the oligotrophic north pacific. J Geophys Res Oceans 115(C2).
  7. Casey KS, Cornillon P (1999) A comparison of satellite and in situ–based sea surface temperature climatologies. J Clim 12(6):1848–1863, doi:10.1175/1520-0442(1999)012<1848:acosai>;2CrossRefGoogle Scholar
  8. Chiswell SM, Calil PH, Boyd PW (2015) Spring blooms and annual cycles of phytoplankton: a unified perspective. J Plankton Res 37(3):500–508.
  9. Collins C, Hermes J, Reason C (2014) Mesoscale activity in the Comoros Basin from satellite altimetry and a high-resolution ocean circulation model. J Geophys Res Oceans 119(8):4745–4760, doi:10.1002/2014JC010008Google Scholar
  10. Conkright ME, Locarnini RA, Garcia HE, O’Brien TD, Boyer TP, Stephens C, Antonov JI (2002) World Ocean Atlas 2001: objective analyses, data statistics, and figures: CD-ROM documentation. US Department of Commerce, National Oceanic and Atmospheric Administration, National Oceanographic Data Center, Ocean Climate LaboratoryGoogle Scholar
  11. Da Silva A, Young C, Levitus S (1994) Atlas of surface marine data 1994, vol. 1, algorithms and procedures, NOAA atlas nesdis 6. US Department of Commerce, NOAA, NESDIS, USA, 74Google Scholar
  12. de Ruijter WP, Ridderinkhof H, Lutjeharms JR, Schouten MW, Veth C (2002) Observations of the flow in the Mozambique Channel. Geophys Res Lett 29(10). CrossRefGoogle Scholar
  13. Debreu L, Vouland C, Blayo E (2008) AGRIF: Adaptive grid refinement in Fortran. Comput Geosci 34(1):8–13. CrossRefGoogle Scholar
  14. DiMarco SF, Chapman P, Nowlin WD, Hacker P, Donohue K, Luther M, Johnson GC, Toole J (2002) Volume transport and property distributions of the Mozambique Channel. Deep-Sea Res II Top Stud Oceanogr 49(7):1481–1511. CrossRefGoogle Scholar
  15. Falkowski PG, Ziemann D, Kolber Z, Bienfang PK (1991) Role of eddy pumping in enhancing primary production in the ocean. Nature 352(6330):55. CrossRefGoogle Scholar
  16. Franks PJ (2009) Planktonic ecosystem models: perplexing parameterizations and a failure to fail. J Plankton Res 31(11):1299–1306. CrossRefGoogle Scholar
  17. George JV, Nuncio M, Chacko R, Anilkumar N, Noronha SB, Patil SM, Pavithran S, Alappattu DP, Krishnan K, Achuthankutty C (2013) Role of physical processes in chlorophyll distribution in the western tropical Indian Ocean. J Mar Syst 113:1–12. CrossRefGoogle Scholar
  18. Harlander U, Ridderinkhof H, Schouten M, De Ruijter W (2009) Long-term observations of transport, eddies, and rossby waves in the Mozambique Channel. J Geophys Res Oceans 114(C2).
  19. José YS, Aumont O, Machu E, Penven P, Moloney C, Maury O (2014) Influence of mesoscale eddies on biological production in the Mozambique Channel: several contrasted examples from a coupled ocean-biogeochemistry model. Deep-Sea Res II Top Stud Oceanogr 100:79–93. CrossRefGoogle Scholar
  20. Kobayashi T, Suga T (2006) The Indian Ocean Hydrobase: a high-quality climatological dataset for the Indian Ocean. Prog Oceanogr 68(1):75–114. CrossRefGoogle Scholar
  21. Koné V, Aumont O, Lévy M, Resplandy L (2009) Physical and biogeochemical controls of the phytoplankton seasonal cycle in the Indian ocean: a modeling study. In: Indian Ocean Biogeochemical Processes and Ecological Variability, pp 147–166. CrossRefGoogle Scholar
  22. Large WG, McWilliams JC, Doney SC (1994) Oceanic vertical mixing: a review and a model with a nonlocal boundary layer parameterization. Rev Geophys 32(4):363–403. CrossRefGoogle Scholar
  23. Liu WT, Tang W, Polito PS (1998) NASA scatter meter provides global ocean-surface wind fields with more structures than numerical weather prediction. Geophys Res Lett 25(6):761–764. CrossRefGoogle Scholar
  24. Malauene B, Shillington F, Roberts M, Moloney C (2014) Cool, elevated chlorophyll-a waters off Northern Mozambique. Deep-Sea Res II Top Stud Oceanogr 100:68–78. CrossRefGoogle Scholar
  25. McGillicuddy D Jr, Robinson A (1997) Eddy-induced nutrient supply and new production in the Sargasso Sea. Deep-Sea Res I Oceanogr Res Pap 44(8):1427–1450. CrossRefGoogle Scholar
  26. Mignot J, de Boyer Montégut C (2006) Control of salinity on the mixed layer depth in the world ocean. In: Geophysical Research Abstracts. vol 8. p 05655.
  27. Penven P, Marchesiello P, Debreu L, Lefevre J (2008) Software tools for pre-and post-processing of oceanic regional simulations. Environ Model Softw 23(5):660–662. CrossRefGoogle Scholar
  28. Prasad T (2004) A comparison of mixed-layer dynamics between the Arabian Sea and Bay of Bengal: one-dimensional model results. J Geophys Res Oceans 109(C3).
  29. Pripp T, Gammelsrød T, Krakstad J (2014) Physical influence on biological production along the western shelf of Madagascar. Deep-Sea Res II Top Stud Oceanogr 100:174–183. CrossRefGoogle Scholar
  30. Roxy MK, Modi A, Murtugudde R, Valsala V, Panickal S, Prasanna Kumar S, Ravichandran M, Vichi M, Lévy M (2016) A reduction in marine primary productivity driven by rapid warming over the tropical Indian ocean. Geophys Res Lett 43(2):826–833. CrossRefGoogle Scholar
  31. Sætre R, Da Silva AJ (1982) Water masses and circulation of the Mozambique channel. Revista de Investigação Pesqueira 3:1–83Google Scholar
  32. Sætre R, Da Silva AJ (1984) The circulation of the Mozambique Channel. Deep Sea Res Part A. Oceanographic Res Pap 31(5):485–508. CrossRefGoogle Scholar
  33. Schouten MW, de Ruijter WP, Van Leeuwen PJ, Ridderinkhof H (2003) Eddies and variability in the Mozambique Channel. Deep-Sea Res II Top Stud Oceanogr 50(12):1987–2003. CrossRefGoogle Scholar
  34. Shchepetkin AF, McWilliams JC (2005) The regional oceanic modeling system (ROMS): a split-explicit, free-surface, topography-following-coordinate oceanic model. Ocean Model 9(4):347–404. CrossRefGoogle Scholar
  35. Sunda WG, Huntsman SA (1995) Iron uptake and growth limitation in oceanic and coastal phytoplankton. Mar Chem 50(1-4):189–206. CrossRefGoogle Scholar
  36. Tang D, Kawamura H, Lee M-A, Van Dien T (2003) Seasonal and spatial distribution of chlorophyll-a concentrations and water conditions in the gulf of Tonkin, south china sea. Remote Sens Environ 85(4):475–483. CrossRefGoogle Scholar
  37. Tegen I, Fung I (1995) Contribution to the atmospheric mineral aerosol load from land surface modification. J Geophys Res-Atmos 100(D9):18707–18726. CrossRefGoogle Scholar
  38. Tew-Kai E, Marsac F (2009) Patterns of variability of sea surface chlorophyll in the Mozambique Channel: a quantitative approach. J Mar Syst 77(1):77–88. CrossRefGoogle Scholar
  39. Ullgren JE, André E, Gammelsrød T, Hoguane AM (2016) Observations of strong ocean current events offshore Pemba, Northern Mozambique. J. Oper. Oceanogr. 9(1):55–66. CrossRefGoogle Scholar
  40. Wiggert J, Jones B, Dickey T, Brink K, Weller R, Marra J, Codispoti L (2000) The northeast monsoon’s impact on mixing, phytoplankton biomass and nutrient cycling in the Arabian Sea. Deep-Sea Res II Top Stud Oceanogr 47(7):1353–1385. CrossRefGoogle Scholar
  41. Wiggert J, Murtugudde R, McClain C (2002) Processes controlling interannual variations in wintertime (northeast monsoon) primary productivity in the central Arabian Sea. Deep-Sea Res II Top Stud Oceanogr 49(12):2319–2343. CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Laboratório de Dinâmica e Modelagem Oceânica (DinaMO), Instituto de Oceanografia, Universidade Federal do Rio Grande -FURGRio GrandeBrazil
  2. 2.Escola Superior de Ciências Marinhas e CosteirasUniversidade Eduardo Mondlane -UEMQuelimaneMozambique
  3. 3.Institute of Coastal ResearchHelmholtz-Zentrum GeesthachtGeesthachtGermany

Personalised recommendations