남해 장목만 중형동물플랑크톤 군집의 변동 특성과 환경요인과의 상관성

Abstract

The weekly variations of mesozooplankton communities in the Jangmok Bay were investigated with the samples collected at intervals of one week from January to December 2009. A single site in the bay was sampled 50 times. Relationships between mesozooplankton abundances and environmental factors such as seawater temperatures, salinities, dissolved oxygen, transparency and chlorophyll-a, Noctilluca scintillans contents were also studied. Mesozooplankton community consisted of 44 taxa and the annual mean abundance was 8,308 ind. m-3 during the survey period. The maximum abundance was observed to be 50,043 ind. m-3 in August and the minimum in April with 1,013 ind. m-3. Penilia avirostris, cirripedia larvae, Evadne tergestina, Acartia omorii, Oikopleura sp., Paracalanus parvus s. l, Eurytemora pacifica, Podon spp, Oithona spp, Acartia steueri were most dominant species in Jangmok bay and they contributed 79% annual mean abundance of total mesozooplankton. Dominant species in each seasonal community were derived from Non-metric multidimensional scaling(nMDS) and SIMPER as follows: winter-spring community (copepodites, A.omorii, E. pacifica), summer community (P. avirostris), and autumn community (Cirripedia larvae, Oikopleura sp.). nMDS revealed significant differences(p<0.05) in the structures of the mesozooplankton community among the three group(winter-spring community, summer community, autumn community). In the redundancy analysis (RDA), dominant species were significantly correlated with temperature(λ=0.37), salinity(λ=0.04), and dissolved oxygen(λ=0.04). Major taxa were significantly correlated with temperature(λ=0.41), dissolved oxygen(λ=0.04), and N. scintillans abundance(λ=0.04). Mesozooplankton abundance was strongly correlated with temperature. Mesozooplankton communities in Jangmok Bay showed typical characteristics of temperate waters, which were dominated by a few species, and abrupt weekly variations in abundance.