龙须菜(Gracilaria lemaneiformis)的生长、光合作用及其对扇贝排泄氮磷的吸收

Studies on growth and photosynthesis characteristics of Gracilaria lemaneiformis and its capacity to uptake ammonium and phosphorus from scallop excretion

研究了不同温度、光照条件下大型藻类龙须菜 （Gracilaria lemaneiformis）的生长和光合作用特性,及其对扇贝排泄氮、磷的吸收作用.结果表明温度与龙须菜的生长和光合作用显著相关,在本实验条件下,15～25℃都适宜龙须菜生长,其中20℃龙须菜具有较高的生长率（SGR）,为2.8%/d;光合作用速率随温度升高和光照的增加而升高,30℃和120 μmol/（m^2·s）时最高,最大光合作用速率（Pmax）为5.0 mg O2/（g dw·h）.龙须菜对扇贝排泄氮、磷有较强的吸收作用,其吸收率和去除效率与放养密度和养殖时间有关.对NH4-N和PO4-P的最大去除效率分别为83.7%和70.4%,最大吸收率分别为9.9 μmol/（g ww·h）和4.3 μmol/（g ww·h）.实验证明龙须菜生长温度范围和光照范围适合中国北方海区养殖,并且能有效吸收和去除扇贝排泄氮、磷,可以作为生物滤器与贝类及其他养殖动物进行综合养殖.

Growth and photosynthesis characteristics of high temperature tolerant macroalga, Graeilaria lemaneiformis, were studied at different temperature and light irradianee. Nutrient uptake rate and nutrient reduction efficiency of ammonium and phosphorus from scallop excretion were determined. Temperature significantly affected the growth and photosynthesis of this species. The algae could grow well when the temperature ranged 15℃ and 25℃, and reached the fastest growth rate （SGR） of 2.8% per day at 20℃. The photosynthetic rate increased with the increasing temperature and light irradiance, reaching the maximum with 5.0 mg O2/（ g dw·h） at 30℃ and 120μmol/（ m^2·s）. G. lemaneiformis can absorb efficiendy the ammonium and phosphorus from scallop excretion. The nutrient uptake rate and nutrient reduction efficiency of ammonium and phosphorus changed with cultivation density and period. The maximum reduction efficiency of ammonium and phosphorus were 83.7 and 70.4 percent, respectively. The maximum uptake rate of ammonium and phosphorus were 9.9μmol/（g ww·h） and 4.3μmol/（g ww·h）. Results indicated that this seaweed can be cultivated in north China and is a suitable candidate for integrated mariculture of seaweed and bivalve. The integration can benefit economy and environment in a sustainable manner in warm seasons in coastal waters of north China.