황해에서 크기별 식물플랑크톤의 생체량 및 종조성

Abstract

We investigated phytoplankton biomass and composition to understand latitudinal differences of size-fractionated phytoplankton structure in the Yellow Sea in April 2011, 2012 and August 2010, 2011. The surveyed stations were selected along lines from coastal to off-shore waters (124.5 and 125.5°E) located at two latitudes (34.5 and 36°N). Water temperature in the surface waters differed before and after formation of bottom cold waters, whereas cold waters (<10℃) in the bottom layer existed consistently. Total chl-a concentration of surface waters, representing the standing crop of phytoplankton, was higher in spring (Avg. 2.20 cells L-1) than in summer (Avg. 1.06 cells L-1) at both latitudes. Micro-sized (>20μm) phytoplankton dominated at the north and south latitudes in spring. Small centric diatoms were abundant at the north latitude, while nanoflagellates predominated at the south latitude in summer. In the bottom waters, total chl-a concentration was higher in summer (Avg. 1.12 μgL-1) than in spring (Avg. 0.67 μgL-1). Nanoflagellates dominated the total chl-a concentration of bottom cold waters at both latitudes in summer, whereas Paralia sulcata and Skeletonema costatum dominated the entire phytoplankton community at both latitudes in spring. Hetero-nanoflagellates (HNF), small centric diatom (Thalassiosira proschkinae and Th. oceania) and nanoflagellates dominated at both latitong lines from coastal to off-shore waters (124.5 and 125.5°E) located at two latitudes (34.5 and 36°N). Water temperature in the surface waters differed before and after formation of bottom cold waters, whereas cold waters (<10℃) in the bottom layer existed consistently. Total chl-a concentration of surface waters, representing the standing crop of phytoplankton, was higher in spring (Avg. 2.20 cells L-1) than in summer (Avg. 1.06 cells L-1) at both latitudes. Micro-sized (>20μm) phytoplankton dominated at the north and south latitudes i