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Peacock EE, Olson RJ, Sosik HM
Parasitic infection of the diatom Guinardia delicatula, a recurrent and ecologically important phenomenon on the New England Shelf
A multi-year record of plankton images collected by Imaging FlowCytobot at a coastal observatory was used to quantify the occurrence of the diatom Guinardia delicatula and its interactions with a nanoflagellate parasite. Parasite infection events are recurrent on the New England Shelf and a negative relationship between diatom bloom magnitude and parasite infection rate supports the hypothesis that the parasites play a major role in bloom control. Notably, infecting parasite stages are abundant only when water temperature exceeds 4°C. During a recent anomalously warm winter, parasites remained active and the Guinardia winter bloom was suppressed. As climate change continues, cold winter periods may shorten or disappear, suggesting that parasite effects may increase, with immediate impacts on Guinardia population dynamics.
