Modelling Ocean Biogeochemistry: The View From The Bottom Of The Food Chain

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Ocean Science in Action - Oceans of the future

3. Introduction to global ocean modelling

3.2 Modelling Ocean Biogeochemistry: The View From the Bottom of the Food Chain

Video duration - 07:39

In many parts of the ocean, the growth of phytoplankton is strongly seasonal and responsible for the phenomenon known as the “spring bloom”.

In this, populations of phytoplankton grow explosively over the space of just a few weeks, resulting in surface chlorophyll concentrations that are visible to orbiting satellites. These blooms are driven by the confluence of several key growth factors. Principally, seasonal change in the availability of light, but also by the availability of certain nutrients, such as nitrate and phosphate. These nutrients occur at high concentrations deep in the ocean, but are mixed into surface waters by processes such as storms, particularly during the winter.

When light and nutrients are both favourable, the resulting growth in phytoplankton numbers can outstrip consumption by grazing animals – zooplankton – triggering blooms. These typically end when phytoplankton have consumed all of the nutrients, at which point zooplankton numbers can catch up, process the phytoplankton they’ve eaten, and ultimately fuel the rest of the food web – including the fisheries than many human communities are dependent upon.

Dr A. Yool - NOC

Further Reading:

Sarmiento J.L., & Gruber, N. (2006). Ocean Biogeochemical Dynamics. Princeton, NJ: Princeton Univ. Press. ISBN 978-0-691-01707-5

Williams, R., & Follows, M. (2011). Ocean Dynamics and the Carbon Cycle: Principles and Mechanisms. Cambridge: Cambridge University Press. doi:10.1017/CBO9780511977817

See also:

Web Resource: Microbiological Garden

Image data set of microbial organisms and their classifications

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