Joanna W. Doinsing, (2010) Effects of salinity, temperature and irradiance on the growth of Cochlodinium Polykrikoides. Masters thesis, Universiti Malaysia Sabah.
Harmful algal blooms (HABs) or "red tides" in Sabah have significantly increased in scale, duration and frequency. The most recent causative species is the Cochlodinium polykrikoides. Since the first occurrence in January 2005, there have been recurring blooms of the species in the coastal waters of western Sabah. To understand the blooming mechanism of the algae, field and laboratory studies were both carried out. Field studies were carried out at University Malaysia Sabah Jetty off Sepanggar Bay, Kota Kinabalu, Sabah during the period of June 2006 to January 2007, with emphasis on temperature, salinity and transparency factors. The range of temperature, salinity and transparency recorded during bloom periods were 30.4-32.1°C (31.1±0.7°C), 31.1-32.8 ppt (32.2±0.7 ppt) and 1.5-3.5 m (2.5±0.9 m) respectively while the range of temperature, salinity and transparency recorded during non bloom periods were 29.2-31.1°C (30.2±0.7°C), 29.8-31.5 ppt (30.4±0.5 ppt) and 3.5-5.6 m (5.1±0.7 m). A low, negative relationship was observed between transparency and C. Polykrikoides cell densities (r=0.3325; p<0.05) while no significant relationships was observed with temperature and salinity (p>0.05). In the laboratory experiments, batch cultures were grown at 4 sets of temperatures (20°C, 25°C, 30°C and 35°C), 8 different salinities (5, 10, 15, 20, 25, 30, 35 and 40 ppt) and 4 levels of irradiances (50, 100, 150 and 200 µmolm-2.s-1). It was observed that Cochlodinium polykrikoides grew well at higher temperatures (25-30°C) and salinities (15-40 ppt) with maximum growth at temperature 30°C and salinity of 30 ppt (0.66 Div. day-1). The optimum growth rate of >0.3 Div. day-l was observed at temperature of 25-30°C and salinities of 20-35 ppt. At all irradiances tested, higher growth rate was detected at irradiance 50 µmolm-2.s-1 with exponential growth rates of 0.78±0.03 Div. day-1. Based on the field and laboratory studies, optimum growth parameters for Cochlodnium polykrikoides are high temperatures and salinities (30-32°C, 30-33 ppt). These results provide vital Information for Cochlodinium polykrikoides blooms monitoring and mitigation programs to lessen the negative impacts from these species.
|Item Type:||Thesis (Masters)|
|Uncontrolled Keywords:||temperature, salinity, irradiance, Cochlodinium polykrikodes, transparency factor, bloom period, mitigation program, algae|
|Subjects:||Q Science > QK Botany|
|Divisions:||SCHOOL > Borneo Marine Research Institute|
|Deposited By:||IR Admin|
|Deposited On:||09 Jul 2013 11:50|
|Last Modified:||09 Jul 2013 11:50|
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