동해 울릉분지에서 봄과 여름동안 시계방향 와류가 영양염과 엽록소에 미치는 영향 = The Effect of Anticyclonic Eddy on Nutrients and Chlorophyll During Spring and Summer in the Ulleung Basin, East Sea

국문 초록 (Abstract)

동해 울릉분지에서 봄과 여름 동안 난수성 시계방향 와류가 영양염과 엽록소에 미치는 영향을 파악하기 위해서, 2005년 7월과 2006년 4월에 5개 정점에서 표층부터 수심 200 m까지 수온, 염분, 영양염, 엽록소 등을 관측하였다. 봄에는 와류 내부해역에서 표층 혼합층의 깊이가 150 m 이상으로 매우 깊은 반면, 외부해역에서는 $20{\sim}60$ m로 비교적 얕았다. 와류 내부해역에서 수직혼합이 활발히 일어나 표층해수에 영양염이 풍부한 반면, 외부해역에서는 표층에서 성층화가 생겨 심층에서 표층으로 영양염 공급이 충분하지 않아 농도가 낮았다. 봄에는 와류 내부해역에서 표층 혼합층 깊이가 유광층 깊이보다 훨씬 더 깊어서 엽록소 농도가 낮았으며, 와류 외부해역에서 측정한 총 엽록소(depth-integrated chlorophyll) 양은 내부해역에서 측정한 것보다 보다 두 배 이상 높았다. 여름에는 봄과 달리 모든 정점에서 표층 성층화가 강하게 발생하여, 영양염이 표층에서 완전히 고갈되었다. 여름에 관측한 엽록소는 모든 정점 수심 30 m 내외에서 최고 농도를 나타내어, 아표층 엽록소 최대(subsurface chlorophyll maximum)를 보였으며, 와류 내부해역에서 측정한 총 엽록소 양은 외부해역에서 측정한 것보다 두 배가량 높았다. 동해 울릉분지에서 거의 매해 나타나는 시계방향 와류는 식물플랑크톤 생물량에 매우 큰 영향을 미치는데, 그 영향이 봄과 여름에 다르게 나타났다; 봄에는 시계방향 와류가 식물플랑크톤 생물량을 제한하는 반면, 여름에는 반대로 식물플랑크톤 생물량을 증가시킨다.

다국어 초록 (Multilingual Abstract)

In order to find out the effects of the anticyclonic eddy on the distribution of nutrients and chlorophyll concentrations in the Ulleung Basin during spring and summer, we measured temperature, salinity, nutrients, and chlorophyll from the surface to 200 m water depth at five stations in July 2005 and April 2006. In spring, surface mixed layer was very deep inside the eddy, about 200 m, but it was relatively shallow outside the eddy, about $20{\sim}60$ m. Inside of the eddy, nutrients in the surface waters were sufficient by supply from the deep layer, whereas outside of the eddy, they were fairly depleted due to the stratification in the surface layer. In spring, chlorophyll concentrations were relatively low inside of the eddy due to the deeper surface mixed layer compared with the euphotic depth, and the depth-integrated chlorophyll concentrations outside of the eddy were twice as much as those inside of the eddy. In summer, nutrients in the surface waters were completely depleted at all stations due to the well stratification in the surface layer. The typical distribution pattern of subsurface chlorophyll maximum was observed at all stations, and the depth-integrated chlorophyll concentrations inside of the eddy were almost twice as much as those outside of the eddy. The anticyclonic eddy appearing in the Ulleung Basin every year significantly affects the phytoplankton biomass, with the opposing effects in spring and summer; in spring, the anticyclonic eddy suppresses phytoplankton growth, but in summer, it enhances the phytoplankton biomass.

참고문헌 (Reference)

1 "한국 동해의 기초생산력과 질소계 영양염의 동적관계" 52-61, 1989

2 "동해남서해역 와류의 물리적 구조" 30 : 170-183, 1995

3 "동해 남서해역에서의 난수성 소용 돌이에 대하여" 152-163, 1994

4 "Theoretical results concerning light absorption in a descrete medium and application to specific absorption of phytoplankton" 1375-1393, 1981

5 "Rotary motions and convection as a means of regulating primary production in warm core ring" 3237-3248, 1985

6 "Prediction of phytoplankton growth in response to the frictional decay of a warm-core ring" 7603-7610, 1986

7 "Movement and structural variation of warm eddy WE92 for three years in the Western East/Japan Sea" 52 : 1742-1762, 2005

8 "Mechanisms for vertical nutrient transport within a North Atlantic mesoscale eddy" 48 : 757-773, 2001

9 "Influence of mesoscale eddies on nitrate distribution during the POMME porgram in the northeast Atlantic Ocean" 55 : 155-175, 2005

10 "Impact of a cyclonic eddy on phytoplankton community structure and photosynthetic competency in the subtropical North Pacific Ocean" 50 : 829-847, 2003

11 "Enhanced new production observed from the diurnal cycle of nitrate in an oligotrophic anticyclonic eddy" 28 : 1579-1582, 2001

12 "Eddy-induced nutrient supply and new production in the Sargasso Sea" 44 : 1427-1450, 1997

13 "Biological enhancement at cyclonic eddies tracked with GOES thermal imagery in Hawaiian waters" 28 : 1583-1586, 2001

14 "Bering Sea cyclonic and anticyclonic eddies observed during summer 2000 and 2001" 55 : 65-75, 2002