Horizontal Distribution and Seasonal Change of Picophytoplankton in SurFace Water of Lake Biwa

  • Goto, Naoshige (Limnological Laboratory, School of Environmental Science University of Shiga Prefecture) ;
  • Mitamura, Osamu (Limnological Laboratory, School of Environmental Science University of Shiga Prefecture) ;
  • Masaki, Kihira (Limnological Laboratory, School of Environmental Science University of Shiga Prefecture)
  • Published : 2005.04.30

Abstract

Seasonal change in cell number and biomass expressed as chlorophyll a of picophytoplankton community in surface waters was investigated in the north basin of Lake Biwa from September 2001 to November 2002. Two main peaks, in May and summer (from July to October), were observed by change of the cell density of picophytoplankton. It is considered that peak in May was due to water temperature rise and summer peak was attributed to mass-specific nutrient uptake by picophytoplankton. Horizontal distribution in cell number and biomass of picophytoplankton community in surface water of Lake Biwa was investigated at 56 stations on June 6 ${\sim}$ 7 2002. DIN and DIP concentrations were lower in the north basin than in the south basin. The cell density and chlorophyll a of picophytoplankton were distributed almost uniformly in all area. The contribution of picophytoplankton to total phytoplankton chlorophyll a was higher in the north basin than in the south basin. These results suggest that picophytoplankton is important as a primary producer in low nutrient periods and areas of Lake Biwa.

Keywords

References

  1. Bendschneider, K. and R.J. Robinson. 1952. A new spectrophotometric method for the determination of nitrite in sea water. J. Mar. Res. 11: 87-96.
  2. Holm-Hansen, O., C.J. Lorenzen, R.W. Holmes and J.D.H. Strickland. 1965. Fluorometric determination of chlorophyll. J. Cons. perm. int. Explor. Mer. 30: 3-15.
  3. Maeda, H., A. Kawai and M.N. Tilzer. 1992. The water bloom of cyanobacterial picoplankton in Lake Biwa, Japan. Hydrobiologia 248: 93-103.
  4. Mitamura, O. 1997. An improved method for the determination of nitrate in freshwaters based on hydrazinium reduction. Memoirs of Osaka Kyoiku University, Ser III 45: 297-303.
  5. Mitamura, O., H. Maeda and M. Kawashima. 1999. Seasonal change in photosynthetic activity of photoautotrophic picoplankton in Lake Biwa. Jpn. J. Limnol. 60: 453-467.
  6. Murphy, J. and J.P. Riley. 1962. A modified single solution method for the determination of phosphate in natural waters. Anal. Chim. Acta 27: 31-36.
  7. Nagata, T., K. Takai, K. Kawabata, M. Nakanishi and J. Urabe. 1996. The trophic transfer via a picoplankton-flagellate-copepod food chain during a picocyanobacterial bloom in Lake Biwa. Arch. Hydrobiol. 137: 145-160.
  8. Nakano, S., K. Tanaka, T. Sono, T. Wakabayashi, S. Ichise, S. Yamanaka, E. Kaneda, M. Yamada, M. Naito, K. Kawabe, K. Maehata, N. Fujiwara, N. Maeda, K. Nomura and M. Nakanishi. 1996. Seasonal changes in horizontal distribution of algal picoplankton in Lake Biwa with special reference to water temperature, nutrient levels and heterotrophic flagellates. Jpn. J. Limnol. 57: 49-55.
  9. Raven, J.A. 1998. The twelfth Tansley Lecture. Small is beautiful: the picophytoplankton. Functional Ecology 12: 503-513.
  10. Sagi, T. 1966. Determination of ammonia in sea water by the indophenol method and its application to the coastal and off-shore waters. Oceanogr. Mag. 18: 43-51.
  11. Sieburth, J. McN., V. Smetecek and J. Lenz. 1978. Pelagic ecosystem structure: heterotrophic compartments of the plankton and their relationships to plankton size fractions. Limnol. Oceanogr. 23: 1256-1263.
  12. Stockner, J.G. and N.J. Antia. 1986. Algal picoplankton from marine and freshwater ecosystems: a multidisciplinary perspective. Can. J. Fish. Aquat. Sci. 43: 2472-2503.
  13. Tezuka, Y. 1985. C : N : P ratios of seston in Lake Biwa as indicators of nutrient deficiency in phytoplankton and decomposition process of hypolimnetic particulate matter. Jpn. J. Limnol. 46: 239-246.
  14. Wakabayashi, T., S. Ichise, N. Fujiwara, N. Maeda, K. Maehata, K. Kawabe, M. Naito, E. Kaneda, M . Yada, S. Yamanaka, T. Sono, K. Tanaka and K. Nomura. 1994. Picoplnakton in recent years in Lake Biwa 1991-1993. Rep. Shiga. Pref. Inst. Pub. Hlth. and Environ. Sci. 29: 95-100.
  15. Weisse, T. 1988. Dynamics of autotrophic picoplankton in Lake Constance. J. Plankton. Res. 10: 1179-1188.