大型海藻养殖对水体DO含量的影响

为了解大型海藻养殖对海水DO含量的影响，明确其在光照、黑暗及光暗交替条件下海水DO含量的变化过程。笔者将取自温州洞头近海养殖的鼠尾藻、羊栖菜带至实验室内进行养殖实验，设置光照（2、6、12 h）、黑暗（2、6、12 h）、光暗交替（1 h 1 h、6 h 6 h、12 h 12 h）处理，测定养殖水体DO含量，对其产氧速率、耗氧速率等进行分析。结果表明：随着光照时间的延长，鼠尾藻、羊栖菜产氧速率都逐渐下降，鼠尾藻的产氧速率比羊栖菜高（P<0.05）；黑暗条件下，鼠尾藻耗氧速率在6 h时达最高288.02 mg/kg DW?h，羊栖菜耗氧速率在2 h时达最高207.46 mg/kg DW?h，鼠尾藻的耗氧速率比羊栖菜高；光暗交替下鼠尾藻的净产氧速率先急剧降低后缓慢升高，短光暗交替周期（1 h 1 h）时净产氧速率最高457.08 mg/kg DW?h。羊栖菜净产氧速率先升高后降低，在中光暗交替周期（6 h 6 h）时最高64.04 mg/kg DW?h。大型海藻养殖时随着光暗环境的交替进行，不断发生着光合产氧、暗呼吸耗氧的转换，总体而言海藻养殖提高了水体DO含量。大型海藻养殖的生态、社会价值显著，建议大力推广

The impact on Seawater DO content of Macroscopic algae farming

In order to understand the impact of macroscopic algae farming on seawater DO content, to clear the change process of DO content, in light, dark, light and dark alternately conditions, Sargassum thunbergii and Hizikia fusiforme from Wenzhou Dongtou offshore were brought to the laboratory for breeding. Set light (2h, 6h, 12h), dark (2h, 6h, 12h), alternating light and dark (1h 1h, 6h 6h, 12h 12h) treatment conditions, DO was determined, also to analyzed its oxygen production rate and oxygen consumption rate. The result showed that: with the extension of farming time, Sargassum thunbergii and Hizikia fusiforme oxygen production rates were all declining, Sargassum thunbergii oxygen production rate was higher than Hizikia fusiforme (P<0.05); Under dark conditions, Sargassum thunbergii maximum oxygen consumption rate at the time of 6h up to 288.02mg/kgDW?h, Hizikia fusiforme maximum oxygen consumption rate at the time of 2h up to 207.46 mg / kgDW?h, Sargassum thunbergii oxygen consumption rate was higher than Hizikia fusiforme; Sargassum thunbergii net oxygen production rate under alternating light and dark increased slowly at first and then drastically reduced, the net oxygen production rate up to 457.08 mg / kgDW?h at the short alternating cycle (1h 1h). Hizikia fusiforme net oxygen production rate first increased and then decreased, while the medium alternating cycle (6h 6h) up to 64.04 mg / kgDW?h. Macroscopic algae farming with alternating light and dark environment when carried out, photosynthetic oxygen production and dark respiration oxygen consumption converted continuously. Overall, Macroscopic algae farming increased the DO content of the seawater. Ecological and social value of the macroscopic algae farming was significantly, it should be vigorously promoted.