Do zooplankton traits matter? Scaling up trade-offs to the global scale. Taxa-transcending traits and trade-offs have been shown through lab experiments and literature analyses. But do they matter for ecology and biogeochemistry on the global scale?
In a recent study, we identify a global biogeography of the mesozooplankton feeding strategy. Passive ambushing copepods dominate over actively feeding ones at high latitudes, but not in low latitudes. We are able to reproduce this pattern with a global trade-off based model resolving the two strategies: low-risk low profit ambushing vs. high-risk high-profit cruise and current feeding. The two strategies preferentially target motile microzooplankton and immotile phytoplankton, and thereby entail different pathways for energy moving up the food chain: a carnivorous pathway via microzooplankton to ambush mesozooplankton dominates in high latitudes, where cost efficiency is the main constrain and more energy intensive active feeding cannot compete. In more productive regions, a herbivorous pathway from primary producers directly to mesozooplankton operates. These contrasting pathways govern the resulting biogeography.
The model is particularly sensitive to the configuration of interaction strength within the food web. These are summarized conveniently by the mesozooplankton trophic level. Other ecosystem functions like net primary production and the potential for carbon export to the deep ocean are also sensitive to the food web configuration. We therefore advocate more effort for global compilations of traits as well as ecosystem functions to further assess and refine trait-based models on the global scale.
Read the paper here.
Prowe AEF, Visser AW, Andersen KH, Chiba S, Kiørboe T (2018). Biogeography of zooplankton feeding strategy. Limnol Oceanogr in press DOI: 10.1002/lno.11067