The Influences of Coastal Upwelling on Phytoplankton Community in the Southern Part of East Sea, Korea

Abstract

냉수대 발생 전·후의 해양 환경과 식물플랑크톤 군집 구조 및 크기를 파악을 위해 여름철 빈번하게 냉수대가 발 생되는 동해 남부 해역(울산 정자~부산일광In order to understand environment condition and phytoplankton community before and after coastal upwelling, the influences of upwelling events on phytoplankton community were studied at 18 stations located the Southern part of East Sea, Korea from May to August 2013. The surface water masses showed low temperature and high salinity due to upwelling events at coastal stations (A1, B1, C1). Correlation between temperature and nutrients (DIP, p<0.01; DIN, p<0.01; silicate, p<0.01) was significantly negative. This result could be explained that nutrients were supplied to surface water by the upwelling of bottom water. Phytoplankton communities were composed of 186 species. Phytoplankton abundance were relatively high in May (C1, 726×103 cells L

Variability of Phytoplankton Size Structure in Response to Changes in Coastal Upwelling Intensity in the Southwestern East Sea

“…Conversely, there was a higher proportion of nanophytoplankton (2.0–20.0 μm) and microphytoplankton (20.0–200.0 μm), which prefer nutrient‐rich environments (Koike et al, ; Lee et al, ; Probyn, ; Tremblay et al, ), and there was a slightly positive relationship between their abundance and coastal upwelling ( y = 13.28ln( x ) + 26.54, r 2 = 0.2376, RMSE = 9.664; and y = 11.21ln( x ) + 20.58, r 2 = 0.1134, RMSE = 12.75, respectively) (Figures b and c). On the basis of the results of previous studies, which have shown that nutrient inflow and the mixing of water masses promotes the growth of large phytoplankton (Arin et al, ; Estrada & Blasco, ), this relationship is likely because of the decreasing stability of the water mass and the increasing supply of nutrients with an increased intensity of coastal upwelling (Kim et al, ).…”

“…To investigate the relationship between the intensity of coastal upwelling along the east coast of Korea in relation to alongshore winds and variation in the size structure of dominant phytoplankton, we performed a correlation analysis between UA and the concentration of different size classes of phytoplankton, as shown in Figure . The proportion of picophytoplankton (0.7–2.0 μm), which prefer nutrient‐poor environments and regenerated nitrogen such as ammonium (Koike et al, ; Lee et al, ; Probyn, ; Tremblay et al, ), tended to slightly decrease as the upwelling intensity increased ( y = −24.43ln( x ) + 52.5, r 2 = 0.2469, root mean square error (RMSE) = 17.34) (Figure a) (Agawin et al, ; Cloern & Dufford, ; Decembrini et al, ; Kim et al, ). Conversely, there was a higher proportion of nanophytoplankton (2.0–20.0 μm) and microphytoplankton (20.0–200.0 μm), which prefer nutrient‐rich environments (Koike et al, ; Lee et al, ; Probyn, ; Tremblay et al, ), and there was a slightly positive relationship between their abundance and coastal upwelling ( y = 13.28ln( x ) + 26.54, r 2 = 0.2376, RMSE = 9.664; and y = 11.21ln( x ) + 20.58, r 2 = 0.1134, RMSE = 12.75, respectively) (Figures b and c).…”

“…Several studies have investigated changes in phytoplankton species composition in response to upwelled cold water in the southwestern East Sea (Kim et al, ; Oh et al, ; Rho et al, ). For example, Oh et al () found that the population size and species composition of phytoplankton increased in response to coastal upwelling in the southern part of the East Sea.…”

“…In addition, Rho et al () investigated the effect of physical‐chemical forcing in the Ulleung Basin (UB), located in the southwest of the East Sea, on the plankton community and found that the concentration of fucoxanthin, an indicator pigment for diatoms, was highest in waters where upwelling was present, whereas the concentration of zeaxanthin, an indicator pigment for cyanobacteria, was very low. Kim et al () investigated the cold water field environment and phytoplankton community from Ulsan to Busan in the southwestern East Sea (see Figure ) and showed that the phytoplankton abundance and the proportion of larger phytoplankton was higher when there was upwelling‐induced cold water than when there was strong vertical stratification in the sea. Together, these studies demonstrate that the abundance and composition of phytoplankton are likely to be affected by the upwelling of cold and nutrient‐rich water from the lower layer.…”

Simulation of the Ocean Circulation Around Ulleungdo and Dokdo Using a Numerical Model of High-Resolution Nested Grid

“…특히, 동해 울릉도 및 독도 해역은 동한난류와 북한한류가 교차함에 따라 북상하던 동한난류가 한국 연안으로부터 이안 되어 사행하며 (Hyun et al, 2009;Kim et al, 2014;Baek and Kim, 2018), 이 사행으로부터 첫 번째 마루에서 시계방 향으로 회전하는 울릉 난수성 소용돌이 (An et al, 1994;Lee and Niiler, 2010;Shin et al, 2005)와 독도 주변으로 동한 난류 사행의 첫 번째 골에서 반시계 방향으로 회전하는 독도 냉수성 소용돌이 (Mitchell et al, 2005b; (Wyrtki et al, 1976;Kang and Kang, 1990;Morimoto et al, 2000;Gordon et al, 2002;Lee and Niiler, 2005;Mitchell et al, 2005a;Shin et al, 2019 (Chang et al, 2002 (Shchepetkin and McWilliams, 2005). 수평 격자 체계는 격자 중심에 밀도, 수심, 수온을, 격자의 좌우에 유속의 동서 성분(u), 상하에 남북 성분(v)을 주어 계산의 안 정성과 효율성을 높인 Arakawa-C의 아격자체계를 사용하며 (Arakawa and Lamb, 1977), 수직 격자는 S-좌표계(Stretched terrain-following coordinate)를 사용한다 (Song and Wright, 1998;Shchepetkin and McWilliams, 2005 (Large et al, 1994)…”