Ocean Science Journal

1.3

1738-5261

Ocean Science Journal volume 58, Article number: 24 (2023)

SCIE

[논문]Phase Shift in Vertical Distribution of Macroalgal Assemblages on Udo Islet, Jeju, Korea, After a Decade of Revisiting

Jeong Chan Kang, Myung Sook Kim

강정찬, 김명숙

Hyung Woo Lee, Young Wook Ko

We investigated seasonal macroalgal assemblages using virtual transect lines and 0.25 m−2 quadrats from the upper intertidal zone to subtidal 15 m depth during the period from May 2019 to February 2020 at Udo Islet, Jeju Island. A total of 191 species (15 Chlorophyta, 36 Ocrophyta, and 140 Rhodophyta) were observed among the quadrats, with annual mean biomass of 1998.8 g wet wt m−2. To confirm the decadal variation of the macroalgal assemblage in Udo, we compared our data with previous observations during 2009–2010 at the same locations reported by Kang et al. We were able to confirm that species diversity did not decrease, although subtidal biomass showed a considerable decrease. Notably, the biomass of non-calcareous macroalgae was considerably reduced, whereas calcareous algal biomass doubled despite maintaining the distribution of dominant species. This changing pattern of macroalgal assemblage is similar with the early process of sea-barrenness reported by previous studies on the Jeju coast. In this study, it was not possible to identify the cause of the decrease in abundance of non-calcareous algae, as the survey focused on only macroalgal assemblage without verifying any environmental factors. Further studies identifying additional factors that might be directly connected to marine deforestation, including physiological, chemical, and biological factors, are essential to recovering or at least maintaining the macroalgal community of Udo Islet.

2023.09.07.

https://doi.org/10.1007/s12601-023-00119-w