不同光环境下两种品系坛紫菜DOC分泌特性研究

为明确坛紫菜Porphyry haifanesis在生长过程中溶解有机碳(DOC)的分泌特性,以两种品系"洞头本地菜"和"浙东1号"的坛紫菜为材料进行了不同光照(1500、2000、3800 Lx)和黑暗条件下的室内养殖试验,通过测定养殖水体中DOC、溶解无机碳(DIC)含量变化,对DOC分泌特性进行分析。结果表明:在光照强度2800 Lx下,两种品系的坛紫菜DOC分泌速率与DOC分泌量占固碳量的比例均在光照2h时达最高;在光照6 h条件下,坛紫菜DOC分泌速率与DOC分泌量占固碳量的比例均在2000 Lx时最高;随着黑暗时间的延长,两种品系坛紫菜的DOC分泌速率、DOC分泌量占释碳量的比例均逐渐下降,黑暗2h时,DOC分泌量占释碳量的比例"洞头本地菜"最高达66.09%,"浙东1号"最高达75.04%;光照条件下,两种品系坛紫菜DOC的分泌与碳同化的同步性较弱,而黑暗条件下,DOC的分泌与DIC的释放同步性较强;在光照与黑暗条件下,"浙东1号"坛紫菜DOC分泌基本未表现出滞后效应,"洞头本地菜"坛紫菜DOC分泌在光照6 h后表现出微弱的滞后效应。研究表明,坛紫菜在光照或黑暗条件下,均会向水体中分泌DOC,提高海水中的DOC浓度。

Secretion characteristics of dissolved organic carbon (DOC) in two strains of laver Porphyry haifanesis under different light conditions

Contents of dissolved organic carbon(DOC) and dissolved inorganic carbon(DIC) were determined in the water in two strains ("native Dongtou"and"Eastern Zhejiang No.1") of laver Porphyry haifanesis culture in an indoor at water temperature of 23.1℃ under fluorescent lamp light for 2,6 and 12 h at illumination intensity of 1500, 2000 and 3800 Lx and darkness for 2,6 and 12 h in order to make clear the DOC secretion characteristics of the laver during growth. The results showed that the maximal DOC secretion rate and proportion of DOC secretion in carbon sequestration were observed under the light intensity of 2800 Lx for 2 h,and that the same case was found under the light intensity of 2000 Lx for 6 h. The DOC secretion rate and the proportion of DOC secretion in the re-leased carbon were all found to be decreased gradually with the prolonged dark period,with the maximal proportion of DOC secretion in the released carbon in 2 h dark,with up to 66.09%in strain"native Dongtou",up to 75.04%in strain"Eastern Zhejiang No.1". The weak synchronization of DOC secretion and carbon assimilation was ob-served in the two strains of laver exposed to light conditions, and the strong synchronization was found under the dark condition. Under both the light and dark conditions,however,"Eastern Zhejiang No.1"showed no hysteresis effect of DOC secretion,while"native Dongtou"showed a weak hysteresis effect of DOC secretion in the 6 h light. Overall,the laver secreted DOC to water,ultimately improved the concentration of DOC in seawater under both the light and dark conditions.