Studies on the nutrition and heavy metals absorption of Gracilaria coronopifolia and Gelidium amansii at different salinity

• Main Authors: Hao-Chiun Hsieh, 謝浩鈞
• Other Authors: Sha-Yen Cheng
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/51471516930450500710

碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 94 === Abstract The aimed of this study was to investigate and compare the different degrees of absorption of nutrition (tatol phosphorus and ammonia-N) and heavy metal (cooper, lead, cadmium, zinc, iron and manganese) for Gracilaria coronopifolia and Gelidium amansii when exposed to different salinities of water. The ammonia-N concentration in the water G. coronopifolia exposed to decreased as the duration of the exposure increased. This applied to salinities of 14, 24 and 34 psu especially for salinity of 24 psu at which the absorption of ammonia-N for G. coronopifolia reached 73.6 % after 7 days of exposure. In the water with salinity of 34 psu, G. amansii could absorb 62.3 % of ammonia-N after 7 days of exposure. There was a significant difference (P＜0.05) between salinity and the ammonia-N concentration in G. coronopifolia and G. amansii. This study showed the similar result on tatol phosphorus absorption. Tatol phosphorus concentration in the water G. coronopifolia exposed to decreased as the duration of the exposure increased. This result applied to salinities of 14, 24 and 34 psu. At salinity of 14 psu, the absorption of tatol phosphorus for G. coronopifolia reached 22.8 % after 7 days of exposure. In the water with salinity of 34 psu, G. amansii could absorb 6.1 % of Tatol phosphorus after 7 days of exposure. There was a significant difference (P＜0.05) between salinity and the tatol phosphorus concentration in G.a coronopifolia and G. amansii. When exposed to salinity of 14 and 24 psu, the N:P ratio of G. coronopifolia decreased from 11.6 and 28.4 to 7.13 and 13.5 respectively. The N:P ratio of G. coronopifolia and G. amansii increased from 10.8 and 23.5 to 17.5 and 23.6 respectively at salinity of 34 psu. There was a significant difference (P＜0.05) between N:P ratio of G. coronopifolia and various degrees of salinity but there was no significant difference (P > 0.05) for N:P ratio of G. coronopifolia and G. amansii at salinity of 34 psu. After 7 days of exposure, the heavy metal concentration in water G. coronopifolia or G. amansii exported to was reduced. G. coronopifolia absorbed copper and iron up to 55.8 and 98.7 %, which are greater than the absorption of G. amansi when salinity is 34 psu. While G. amansii demonstrated the better absorption than G. coronopifolia as it absorbed 57.0, 12.9, 67.3 and 15.8 % of lead, cadmium, zinc and manganese when salinity is 34 psu. The statistics showed that there is a significant difference (P < 0.05) between the heavy mental concentration and salinity. There was a positive correlation between the days of exposure and heavy metal accumulation in G. coronopifolia and G. amansii. After 7 days of exposure in the water with salinity of 14 psu, G. coronopifolia accumulated copper, lead, cadmium, zinc and manganese at the highest level of 2.40, 1.43, 0.27, 1.54 and 0.33 mg/g Dry Weight respectively. G. coronopifolia accumulated the highest level of iron at 1.13 mg/g when the salinity is 24 psu. When exposed to salinity of 34 psu, G. coronopifolia accumulated 0.96 mg/g DW of copper, 0.59 mg/g DW of lead, and 1.04 mg/g DW of zinc, significantly exceeding the accumulation in G. amansii which were 0.73 mg/g DW of copper, 0.43 mg/g DW of lead, and 0.15 mg/g DW of zinc (P<0.05). Exported at the same degree of salinity, G. amansii accumulate 0.96 mg/g of cadmium, 0.59 mg/g of iron, and 1.04 mg/g DW of manganese which exceeded the accumulation in G. coronopifolia as 0.12 mg/g DW of cadmium, 0.49 mg/g DW of iron, and 0.16 mg/g DW of manganese. The statistic data showed that there was a significant difference between heavy metal accumulation and salinity (P<0.05). There was a positive correlation between the days of exposure and heavy metal concentration factor in G. coronopifolia and G. amansii. Heavy metal concentration factor in G. coronopifolia reached the highest level at salinity of 14 psu as the copper concentration factor was 3187, lead concentration factor was 4667, zinc concentration factor was 281, and cadmium concentration factor was 31. As for manganese accumulation, the highest levels were achieved at salinity of 24 psu as manganese concentration factor was 127. With the same degree of salinity of 34 psu, all heavy metal concentration factors in G. coronopifolia all exceeded those in G. amansii. The statistic data showed that there was a significant difference between heavy metal concentration factor and salinity (P<0.05).