봄철 및 여름철 황해 식물플랑크톤 생체량과 군집구조의 공간 및 계절 변동

Abstract

This study aimed to understand regional and seasonal variation of phytoplankton biomass and community structure in the Yellow Sea in spring and summer from 2011 to 2013. 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 (8.1-9.6℃) and after (14.6-29.4℃) formation of bottom cold waters, whereas cold waters (<10℃) in the bottom layer existed consistently. Total chlorophyll a concentration of surface waters was higher in spring (avg. 2.56 μgL-1) than in summer (avg. 1.12 μgL-1) at both latitudes. Micro-sized (>20 μm) phytoplankton (Skeletonema spp., Thalassiosira nordenskioeldii and Leptocylindrus danicus) dominated at the north and south latitudes in spring. Small centric diatoms (3-20 μm) were abundant at the north latitude, while nano-flagellates predominated at the south latitude in summer. In the bottom waters, total chl-a concentration was higher in summer (avg. 1.02 μgL-1) than in spring (avg. 0.76 μgL-1) during the study periods. Nano-flagellates dominated the total chl-a concentration of bottom cold waters at both latitudes (33.7-67.4%) in summer, whereas Paralia sulcata and Skeletonema spp. dominated the entire phytoplankton community at both latitudes (41.2-73.3%) in spring. Hetero-nanoflagellates (HNF), small centric diatom (Thalassiosira proschkinae ore waters (124.5 and 125.5°E) located at two latitudes (34.5 and 36°N). Water temperature in the surface waters differed before (8.1-9.6℃) and after (14.6-29.4℃) formation of bottom cold waters, whereas cold waters (<10℃) in the bottom layer existed consistently. Total chlorophyll a concentration of surface waters was higher in spring (avg. 2.56 μgL-1) than in summer (avg. 1.12 μgL-1) at both latitudes. Micro-sized (>20 μm) phytoplankton (Skeletonema spp., Thalassiosira nordenskioeldii and Leptocylindrus danicus) dominated at the north and south latitudes in spring. Small centric diatoms (3-20 μm) were abundant at the north latitude, while nano-flagellates predominated at the south latitude in summer. In the bottom waters, total chl-a concentration was higher in summer (avg. 1.02 μgL-1) than in spring (avg. 0.76 μgL-1) during the study periods. Nano-flagellates dominated the total chl-a concentration of bottom cold waters at both latitudes (33.7-67.4%) in summer, whereas Paralia sulcata and Skeletonema spp. dominated the entire phytoplankton community at both latitudes (41.2-73.3%) in spring. Hetero-nanoflagellates (HNF), small centric diatom (Thalassiosira proschkinae