Seasonal Abundance of Epiphytic Dinoflagellates around Coastal Waters of Jeju Island, Korea

Abstract

The seasonal abundance of epiphytic dinoflagellates in the intertidal zone of Jeju Island, Korea was quantitatively estimated by monthly collection of macroalgal samples (Rhodophyta, Phaeophyta, and Chlorophyta) from six sampling locations from July 2012 to June 2013. Ten epiphytic dinoflagellate taxa, including eight potentially toxic species Amphidinium carterae, A. operculatum, Gambierdiscus sp., Ostreopsis ovata, Prorocentrum concavum, P. emarginatum, P. lima, and P. rhathymum, were identified. Two Amphidinium and three Prorocentrum species are newly recorded in Korean coastal waters. A significant change in seasonal abundance was recorded with maximum (751.82 ± 223.12 cells g^(-1) wet weight of algae; cells g^(-1) hereafter) in June (summer), followed by October (autumn) (650.45 ± 225.02 cells g^(-1)) and September (598.02 ± 197.82 cells g^(-1)). O. ovata was the most abundant (338.21 ± 11 cells g^(-1)), reported in October and Gambierdiscus sp. was the least abundant, which was found only in September (6.92 ± 16.97 cells g^(-1)) and October (6.54 ± 6.54 cells g^(-1)) at Hamduk (St 2). Significantly, highest spatial abundance of total dinoflagellates for all sampling stations was found at Hamduk (St 2) (547.91 ± 315 cells g^(-1)), while it was lowest at Hwasun (St 5) (232.59 ± 144.93 cells g^(-1)). Abundance of all dinoflagellate species was significantly correlated with environmental parameters, with some exceptions. During summer and autumn, increasing abundance of dinoflagellate at all sampling stations compared to the other seasons emphasizes environmental and biological interactions of epiphytic dinoflagellate with host macroalgae. Generally, each of the epiphytic dinoflagellates did not show specific preference of macroalgae as host. However, Chlorophytes were less preferred host by most of the dinoflagellates.