Cryptic speciation of benthic Prorocentrum (Dinophyceae) species and their potential as ecological indicators
Yixuan Wu, Shuning Huang, Bernd Krock, Chui Pin Leaw, Sing Tung Teng, Ajcharaporn Piumsomboon, Porntep Punnarak, Kakaskasen Andreas Roeroe, Na Wang, Haifeng Gu
Abstract
The response of marine ecosystems to rapid climate changes has been well recognized but not studied extensively. Benthic microalgae, in contrast to the phytoplankton that is able to be transported by currents, have \nlimited dispersal ability and thus are a better ecological indicator to climate changes. Here we performed \nsampling in the Yellow Sea, the East China Sea and South China Sea and established twenty-six strains of benthic \nProrocentrum for detailed morphological and molecular examinations. Five Prorocentrum species, including \nP. concavum, P. fukuyoi, P. mexicanum, P. tsawwassenense, and P. cf. sculptile, were identified. Both P. concavum \nand P. fukuyoi displayed marked intraspecific divergences in large subunit (LSU) ribosomal RNA gene sequences, \ncorresponding to their geographical origins. In contrast, P. mexicanum strains shared identical LSU sequence. \nProrocentrum tsawwassenense and P. cf. sculptile are not suitable ecological indicators as they were rarely \nobserved. Prorocentrum mexicanum is not recommended either as it is present across the region. In contrast, \nP. concavum and P. fukuyoi have advantages as ecological indicators for climate changes in the Western Pacific as \nthey comprise several ribotypes with differentiated biogeography. Toxin analysis was also performed on all five \nspecies except P. fukuyoi by liquid chromatography coupled to tandem mass spectrometry, but okadaic acid was \nnot detectable.