Modelling the response of phytoplankton to mesoscale and submesoscale processes at the Sub-Antarctic Front

Zoe Waring


This study extends a basic NPZ (Nutrient, Phytoplankton, Zooplankton) model to investigate the impact of turbulence on phytoplankton growth. Despite recent studies suggesting that submesoscale dynamics are crucial for the transfer of energy and nutrients across eddies, there are relatively few in situ studies and none, before now, at the Sub-Antarctic Front (SAF) to the East of Drake Passage. This study draws on data collected at the SAF and predictions made by the model to give an insight into the processes governing phytoplankton growth across a cold core mesoscale eddy. Conductivity, temperature, nutrient and chlorophyll-a (chl-a) measurements were used to assess physical and biological differences across the eddy. These were then compared to predictions made by the model to assess the response of phytoplankton to the dynamical conditions across the eddy. It was found that the turbulent conditions at the eddy boundary are likely to support a phytoplankton bloom, subsequently triggering an increase in zooplankton. Increased zooplankton levels cause an increase in grazing which is likely to enforce top down control, reducing phytoplankton numbers. The processes controlling growth within the eddy are not so well defined, however it is thought that phytoplankton growth is sustained, although growth in situ may have been limited by a micronutrient such as iron that was not included in the model. A lack of iron was also thought to be the cause of low levels of chl-a outside of the eddy as no other limiting factors were identified in measured or modelled data.

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Ansorge, I. J. et al., 1999. Physical-biological coupling in the waters surrounding the Prince Edward Islands (Southern Ocean). Polar Biology, 21(3), pp. 135-145.

Azam, F., 1998. Microbial control of oceanic flux: The plot thickens. Science, 280(5364), pp. 694-696.

Chaalali, A. et al., 2015. A new modeling approach to define marine ecosystems food-web status with uncertainty assessment. Progress in Oceanography, 135, pp. 37-47.

de Montera, L. et al., 2011. Multifractal analysis of oceanic chlorophyll maps remotely sensed from space. Ocean Science, 7, 219-229.

Death, R. et al., 2014. Antarctic ice sheet fertilises the Southern Ocean. Biogeosciences, 11(10), pp. 2635-2643.

Edwards, C. A., Powel, T. A. & Batchelder, H. P., 2000. The stability of an NPZ model subject to realistic levels of vertical mixing. Journal of Marine Research, 58, pp. 37-60.

Enriquez, R. M. & Taylor, J. R., 2015. Numerical simulations of the competition between wind-driven mixing and surface heating in triggering spring phytoplankton blooms. ICES Journal of Marine Science, 72(6), pp. 1926-1941.

Estrada, M. & Berdalet, E., 1997. Phytoplankton in a turbulent world. Scientia Marina, 61(1), pp. 125-140.

Evans, G. T. & Parslow, J. S., 1985. A model of plankton cycles. Biological Oceanography, 3(3), pp. 327-347.

Falkowski, P. G., Barber, R. T. & Smetacek, V., 1998. Biogeochemical Controls and Feedbacks on Ocean Primary Production. Science, 281(5374), pp. 200-206.

Fennel, W. & Neumann, T., 2015. Introduction to the Modelling of Marine Ecosystems. 2nd ed. Amsterdam: Elsevier.

Fenchel, T., 2008. The microbial loop- 25 years later. Journal of Experimental Marine Biology and Ecology, 366(1-2), pp. 99-103.

Franks, P. J. S., 2002. NPZ Models of Plankton Dynamics: Their Construction, Coupling to Physics, and Application. Journal of Oceanography, 58(2), pp. 379-387.

Franks, P. J. S., Wroblewski, J. S. & Flierl, G. R., 1986. Behaviour of a simple plankton model with food-level aclimation by herbivores. Marine Biology, 91, pp. 121-129.

Fuhrman, J. A., Cram, J. A. & Needham, D. M., 2015. Marine microbial community dynamics and their ecological interpretation. Nature Reviews Microbiology, 13, pp. 133-146.

Glorioso, P. D., Piola, A. R. & Leben, R. R., 2005. Mesoscale eddies in the Subantarctic Front - Southwest Atlantic. Scientia Marina, 69(2), pp. 7-15.

Gomez-Enri, J., Quartly, G. D., Navarro, G. & Villares, P., 2007. Characterizing and following eddies in Drake Passage. Univ Cadiz, Cadiz, Conference: Geoscience and Remote Sensing Symposium, IEEE international.

Goncharov, V. & Pavlov, V., 2001. Cyclostrophic vortices in polar regions of rotating planets. Nonlinear Processes in Geophysics, 8, pp. 301-311.

Holm-Hansen, O. et al., 1994. n situ evidence for a nutrient limitation of phytoplankton growth in pelagic Antarctic waters. Antarctic Science, 6(03), pp. 315-324.

Hosegood, P. J., Sallee, J. B. & Torres, R., 2014. Description of proposed research.

Huisman, J., van Oostveen, P. & Weissing, F. J., 1999. Critical depth and critical turbulence: Two different mechanisms for the development of phytoplankton blooms. Limnology and Oceanography, 44(7), pp. 1781-1787.

Kahru, M., Mitchell, B. G., Gille, S. T. & Hewes, C. D., 2007. Eddies enhance biological production in the Weddell-Scotia Confluence of the Southern Ocean. Geophysical Research Letters, 34(14).

Klein, P. & Lapeyre, G., 2009. The Oceanic Vertical Pump Induced by Mesoscale and Submesoscale Turbulence. Annual Review of Marine Science, 1, pp. 351-357.

Klunder, M. B. et al., 2010. Dissolved iron in the Southern Ocean (Atlantic sector). Deep-Sea Research II, 58, pp. 2678-2694.

Lévy, M., Klein, P. & Treguier, A., 2001. Impact of sub-mesoscale physics on production and subduction of phytoplankton in an oligotrophic regime. Journal of Marine Research, 59, pp. 535-565.

Lévy, M. R. et al., 2012. Bringing physics to life at the submesoscale. Geophysical Research Letters, 39(14), L14602.

Lochte, K. & Pfannkuche, O., 1987. Cyclonic cold-core eddy in the eastern North Atlantic. ii. Nutrients, phytoplankton and bacterioplankton. Marine Ecology- progress series, 39, pp. 153-164.

Martin, J. H., Gordon, R. M. & Fitzwater, S. E., 1990. Iron in Antarctic waters. Nature, 345(6271), pp. 156-158.

Martínez-García, A. & Winckler, G., 2015. Iron fertilization in the glacial ocean. DUST, 24, p. 82.

Miller, C. B., 2006. Biological Oceanography. 4 éd. Oxford: Blackwell Science Ltd.

Moore, K. & Abbott, M. R., 2000. Phytoplankton chlorophyll distributions and primary production in the Southern Ocean. Journal of Geophysical Research, 105(C12), pp. 28,709-28,722.

Nihoul, J. C., 1975. Modelling of marine systems. Elsevier Oceanography Series, 10 ed. Oxford: Elsevier.

Orsi, A. H., Whitworth, T. & Nowlin Jr, W. D., 1995. On the meridonal extent and fronts of the Antarctic Circumpolar Current. Deep Sea Research Part I: Oceanographic Research Papers, 42(5), pp. 641-673.

Philibert, R., Waldron, H. & Clark, D., 2015. A geographical and seasonal comparison of nitrogen uptake by phytoplankton in the Southern Ocean. Ocean Science, 11, pp. 251-267.

Smith, W. O. & Nelson, D. M., 1985. Phytoplankton bloom produced by a receding ice edge in the Ross Sea- spatial coherence with the density field. Science, 227(4683), pp. 163-166.

Sokolov, S. & Rintoul, S. R., 2007. On the relationship between fronts of the Antarctic Circumpolar Current and surface chlorophyll concentrations in the Southern Ocean. Journal of Geophysical Research, 112(C7), pp. 1-17.

Talley, L. D., Pickard, G. L., Emery, W. J. & Swift, J. H., 2011. Descriptive Physical Oceanography. 6th ed. London: Elsevier.

Taylor, J. R. & Ferrari, R., 2011. Ocean fronts trigger high latitude phytoplankton blooms. Geophysical Research Letters, 38, L23601.

Thomas, L. N., Tandon, A. & Mahadevan, A., 2008. Submesoscale Processes and dynamics. Ocean Modelling in an Eddying Regime, pp. 17-38.

Thompson, A. F. & Sallée, J. B., 2012. Jets and Topography: Jet Transitions and the Impact on Transport in the Antarctic Circumpolar Current. American Meteorological Society, 42, pp. 956-972.

Watteaux, R., Stocker, R. & Taylor, J. R., 2015. Sensitivity of the rate of nutrient uptake by chemotactic bacteria to physical and biological parameters in a turbulent environment. Journal of Theoretical Biology, 387, pp. 120-135.


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