University of Cambridge > Talks.cam > Department of Earth Sciences Seminars (downtown) > Ocean turbulence, fronts, and the timing of the spring phytoplankton bloom

Ocean turbulence, fronts, and the timing of the spring phytoplankton bloom

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Phytoplankton, tiny free-floating algae, form the foundation of the ocean food web and are responsible for roughly half the global primary production. In many locations, phytoplankton growth occurs in intense bursts known as blooms. The factors that lead to these blooms, particularly the intense spring bloom, have been the topic of intense study for decades. Here, I will present new evidence that the timing of the spring bloom can be linked to the level of turbulence in the upper ocean and to the strength of atmospheric forcing. While this mechanism is able to predict the overall timing of the spring bloom, phytoplankton growth can be locally modified by ocean fronts. Fronts, or regions with large horizontal density contrasts, suppress vertical mixing, and can thereby trigger phytoplankton blooms during strong atmospheric forcing. By reducing the phytoplankton flux out of the well-lit euphotic layer, fronts can support phytoplankton blooms during harsh wintertime conditions. This mechanism helps to explain satellite-based observations of isolated wintertime phytoplankton blooms.

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Huisman, J., P. van Oostveen, and F. Weissing (1999), Critical depth and critical turbulence: Two different mechanisms for the development of phytoplankton blooms. Limnol. Oceanogr., 44(7), 1781–1787.

Taylor, J.R. and R. Ferrari (2011), Shutdown of turbulent convection as a new criterion for the onset of spring phytoplankton blooms. Limnology and Oceanography, 56(6) 2293-2307.

Taylor, J.R. and R. Ferrari (2011), Ocean fronts trigger high latitude phytoplankton blooms. Geophysical Research Letters, 38, L23601 , doi:10.1029/2011GL049312.

This talk is part of the Department of Earth Sciences Seminars (downtown) series.

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