Ecological observation on Sargassum thunbergii cultivated in ponds

Abstract:

To investigate the bioremediation function of Sargassum thunbergii, the seaweed was cultivated in pond from March 2009 to July 2010, and the growth of thalli cultured in four modes with different temperature, light intensity, salinity or pH was determined. The results showed that: 1) under the same experimental conditions, wild seedlings grew faster than the curtain seedlings, and artificial seedlings grew even slower; 2) water-level between 40 cm and 60 cm was most suitable for the growth of S. thunbergii, and the ranking was 0-20 cm, 80-100 cm, and 150-200 cm, which achieved the slowest growth and the thalli began to drop off due to decaying in mid May; 3) the thalli grew most rapidly at water flow rate of 1 m/s, which slowed down with the decrease of flow rate; 4) the thalli growth was at its best at light intensities between 4000 lx ~6000 lx, and the growth rate was relatively slower with the light intensity above 10000 lx or below 3000 lx. Additionally, this study also showed that from late April to mid May (water temperature, 14-18oC), S. thunbergii entered fast-growth stage, with rapid increase of length and biomass; from mid May to early June (water temperature, 18-23oC), the seaweed started to spawn and its length and biomass reached the maximal values; from mid-to-late June (water temperature, >24oC), the seaweed began to decay and rot off, due to the increase of water temperature.