• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6008-6014
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• 2013

This study aimed to understand seasonal variation of physico-chemical factors and biomass of size-fractionated phytoplankton at Ulsan seaport during the period from February 2007 to November 2009. Water temperature, salinity, dissolved oxygen (DO), pH, chemical oxygen demand (COD) and total suspended solid (TSS) varied in the range of 8.94-$24.26^{\circ}C$, 25.06-34.54 psu, 4.30-10.73 mg/L, 7.97-8.53, 0.66-40.70 mg/L and 57.4-103.3 mg/L, respectively. These factors showed no clear spatial variation unlike spatial pattern of inorganic nutrients and total chlorophyll-a (chl-a) concentration as biomass. Concentration of phosphate, nitrate and silicate ranged from 0.01 to 3.03 ${\mu}M$, 0.05 to 21.62 ${\mu}M$, and 0.01 to 27.82 ${\mu}M$, respectively, with 2 times higher concentration at inner stations than that at outer stations during the study period. Within the range of total chl-a concentration (0.36-7.11 ${\mu}gL^{-1}$), higher concentration (avg. 1.88 ${\mu}gL^{-1}$) of total chl-a were observed at inner stations compared to that (avg. 0.90 ${\mu}gL^{-1}$) at outer stations. Micro-sized phytoplankton dominated total biomass of phytoplankton in spring (34.0-81.2%), summer (35.1-65.6%) and winter (3.9-62.0%). Nano- and pico-sized phytoplankton contributed 58.2-74.5% and 22.4-38.2% to total biomass of phytoplankton in autumn, respectively. However, contribution in biomass of size-fractionated phytoplankton to total phytoplankton biomass showed no clear difference between inner and outer stations. Consequently, these results indicated that spatio-temporal distribution of phytoplankton biomass at Ulsan seaport was dominated by micro-phytoplankton (avg. 52.3%) during the study period except autumn, which was closely dependent on the concentration of inorganic nutrients (p<0.05).