Spring phytoplankton community response after episodic a windstorm event in oligotrophic water of Ulleungdo and Dokdo in the East Sea.

Abstract

We investigated the relationships between horizontal phytoplankton distribution and environmental factors before and after episodic windstorm events at 40 stations in Ulleungdo and Dokdo around waters of the offshore frontal area in the East Sea. Nutrient addition experiments (control, +N, +P, and +NP combined with non-Fe and Fe) were also conducted to determine the growth response and nutrient consumption of the phytoplankton assemblage using the surface water of St.36 and St.40 in Dokdo around water. Diatoms and Raphidophyta were predominant species. Of these, raphidophyta Heterosigma akashiwo abundance is maintained at high level in the offshore oligotrophic area of Dokdo after episodic windstorm events. Therefore, natural phytoplankton including H. akashiwo can rapid response to pulsed nitrogen loading events. The episodic windstorm events, which could allow vertical mixing to bring nutrients into the euphotic upper layer, is one of important role as trigger factor of the spring phytoplankton blooms under potentially oligotrophic area such as Dokdo around water of East Sea.t Sea. Nutrient addition experiments (control, +N, +P, and +NP combined with non-Fe and Fe) were also conducted to determine the growth response and nutrient consumption of the phytoplankton assemblage using the surface water of St.36 and St.40 in Dokdo around water. Diatoms and Raphidophyta were predominant species. Of these, raphidophyta Heterosigma akashiwo abundance is maintained at high level in the offshore oligotrophic area of Dokdo after episodic windstorm events. Therefore, natural phytoplankton including H. akashiwo can rapid response to pulsed nitrogen loading events. The episodic windstorm events, which could allow vertical mixing to bring nutrients into the euphotic upper layer, is one of important role as trigger factor of the spring phytoplankton blooms under potentially oligotrophic area such as Dokdo around water of East Sea.