PhD student Agnethe N. Hansen has recently published a paper in Limnology and Oceanography on the optimal diel vertical migration of zooplankton and its consequences for the global oceanic carbon pump.
It has long been speculated that zooplankton can transport carbon from the surface ocean to below the euphotic zone during their daily vertically migrations (DVM). While many observations have been made, both on the migrating behaviour and the carbon transport, few models have been able to integrate this process up to the global scale. In this paper, Hansen and Visser provide a relatively simple algorithm that can be imbedded into global production models, and provides a means of estimating the regional and seasonally resolved carbon transport for a zooplankton community composed of different sized individuals. The central concept is that DVM is an adaptive behaviour that optimized the trade-off between feeding in the surface at night, and taking refuge form visual predators during daylight hours; a trade-off that depends on the size of the zooplankter, the food abundance in the surface, and the day length and light intensity; factors that vary with time of year and latitude. The model estimates that about 25% of the total export flux of the North Atlantic is associated with the daily vertically migration of zooplankton.
Agnethe N. Hansen and André W. Visser. 2016. Carbon export by vertically migrating zooplankton: an optimal behavior model. Limnology and Oceanography. DOI: 10.1002/lno.10249. http://onlinelibrary.wiley.com/doi/10.1002/lno.10249/full