Is Karenia brevis really a low-light-adapted species?

摘要: Abstract Despite nearly annual blooms of the neurotoxic dinoflagellate Karenia brevis (Davis) G. Hansen and Moestrup in Gulf Mexico, defining suite biological traits that explain its proliferation has remained challenging. Studies have described K. as a low-light-adapted species, incapable sustaining growth under high light, which is at odds with observed surface aggregations sometimes within centimeters sea also short-term experiments showing photosynthetic machinery accommodating irradiances. Here, photophysiology three isolates were evaluated range environmentally relevant irradiances (10–1500 μmol photons m−2 s−1) laboratory. No differences growth–irradiance curves among isolates; all sustained maximum rates highest examined, even exposures long weeks. The efficiency α light-limiting conditions appeared mediocre dinoflagellates, poorer than other phytoplankton (e.g., diatoms, cyanobacteria), implying not low-light specialist. This finding substantially alters earlier parameterizations curves. Therefore, model was developed to contextualize how these new might affect bottom rates. subsequently applied case study comparing seasonal light forcing offshore Pinellas County, FL, USA, single empirical value for attenuation, water temperatures. Predictions suggested may limit close 1 km from shore winter, but would only begin limiting 20 km summer. Population maintenance (no net growth) possible far 90 km summer 68 km winter. These ranges intercept areas thought be important bloom initiation.