竹北淡水魚塭生態之研究

Abstract

Diurnal and seasonal variations of both physico-chemical factors and. biological conditions were studied from Oct. 1957 to Nov. 1969. Samples were obtained at approximately three days or weekly intervals. The following physico-chemical. analysis were made on these samples by standard methods: Temperature, Dissolved Oxygen, Alkalinity (Carbonate and Bicarbonate), Hardness, Magnesium, Calcium, Nitrite, Nitrate, Ammonia, Organic Nitrogen, Silica, Phosphate Phosphorus, Organic Phosphorus, Organic Carbon, COD, Chlorophyll (a & b), Chloride, Water Color and Electric Conductivity. 1. There is a negative correlation between dissolved Oxygen and Temperature, but D, O. always aupersature in fish ponds having higher productivity during Summer. Both of n having the vertical stratifications in shallow pondr more than 80cm, pH, dissolved. Oxygen and Temperature reach the highest concentration during 3 p.m. and 4 p.m., and lowest in 6a.m. 2. Water Color (pt unit, X) has linear relationship with Consumption of Oxygen Demand (Y):X=2.9043 Y-1.7858. 3. There is a roughly curved relationship between chlorophyll Content and Transparency. 4. Total Nitrogen is principally determined by Organic Nitrogen, Inorganic Ammonia is higher than Nitrate Content, and Nitrite is the least. In general, Nitrate and Nitrite show trace in the fish pond during intenuo Photosynthesis. Rain water contains much Nitrate. 5. Higher Alkalinity result in higher productivity of Zooplankton. Carbonate go hand in hand with pH and, reversely with Bioarbonate. Bicarbonate constitutes the 90% of total Alkalinity, 6. The dynamics of Chloride in fish pond may be relative to the Physio1or of Phytoplankton. 7. The time during late February and early July favor the higher productivity of Zooplankton. The most favorable condition of Phytoplankton was found during May and N0vember, The latter always outnumber the former in volume. 8. Higher Electric Conductivity favor the preferencial. growth of Phrtoplankton. 9. Inorganic Phosphorus and Nitrogen fertilizer favor the mass production of Blue Greeon Algae such as Microcystis aruginosa, Coelosphaerium Sn, and Anabaena sp.. 10. Rotifers outnumber Cladocera and Copepods. Rotifers consist of 17 Genus, including 29 known species and 4 unknown species. Branchionus and Keratella show a wide range of adaptability and grow in abundance. 11. The abundance of Blue Green Algae may be due to higher value of dissolved organic matter, lower Silica and Magnesium, Lower pH, dissolyad Oxygen; organic matter; Higher Bioarbonate, Hardness and Chloride favor the grow of Diatoms. Higher Bicarbonate and Calcium; Lower Magnesium, organic matter, pH, Transparency and. Nitrite result in optimal. growth of Green Algae. 12. The principal factor which control the behavior of diurnal movement of Plankton is light. The others are Temperature and dissolved Oxygen. In Zooplankton, the diurnal movement of Cladocera and Copepods is very characteristic, Nauplil. and Filinia longeseta also have diurnal behavior, but none is found in Branchionus forticula, Polyarthra trigla and Trichocera. sp.. Diatoms show weak photosensitivity. The total quantity of Phytoplankton in surface layer is more than the bottom.