Zhao Zhi-Fang, Huang Zhong-Jian, Sun Zuo-Deng, Liu Zheng-Yi, Qin Song, Han Tong, Qi Xin-Yu, Sun Xi-Yan, Zhong Zhi-Hai
Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 101407, China.
Guangxi Academy of Oceanography, Nanning 530022, China.
Mar Pollut Bull. 2023 May;190:114865. doi: 10.1016/j.marpolbul.2023.114865. Epub 2023 Apr 3.
Although macroalgae are regarded as the emerging fourth category of "blue carbon", few studies are available on the dynamics of dissolved organic carbon (DOC) release. Sargassum thunbergii is a typical intertidal macroalgae; and tidal action usually triggers instantaneous changes in temperature, light and salinity. Therefore, we investigated the mechanism of short-term changes in temperature, light and salinity on DOC release by S. thunbergii. As well as these factors coupled with desiccation, the combined effect of DOC release was revealed. The results showed the DOC release rate of S. thunbergii was from 0.028 to 0.037 mg C g (FW) h under different photosynthetically active radiation (PAR, 0-1500 μmol photons m s). The DOC release rate of S. thunbergii was from 0.008 to 0.208 mg C g (FW) h under different salinity (5-40). The DOC release rate of S. thunbergii was from 0.031 to 0.034 mg C g (FW) h under different temperature (10-30 °C). Either the increase in intracellular organic matter concentration due to increased photosynthesis (change in PAR and temperature, active), cell dehydration due to dry-out process (passive) or the decrease in extracellular salt concentration (passive) would lead to an increase in the difference in osmotic pressure and promote DOC release.
尽管大型海藻被视为新兴的第四类“蓝碳”，但关于溶解有机碳（DOC）释放动态的研究却很少。鼠尾藻是一种典型的潮间带大型海藻；潮汐作用通常会引发温度、光照和盐度的瞬时变化。因此，我们研究了温度、光照和盐度短期变化对鼠尾藻DOC释放的影响机制。除了这些因素与干燥作用的耦合外，还揭示了DOC释放的综合效应。结果表明，在不同光合有效辐射（PAR，0 - 1500 μmol光子·m²·s）下，鼠尾藻的DOC释放速率为0.028至0.037 mg C·g（FW）·h。在不同盐度（5 - 40）下，鼠尾藻的DOC释放速率为0.008至0.208 mg C·g（FW）·h。在不同温度（10 - 30°C）下，鼠尾藻的DOC释放速率为0.031至0.034 mg C·g（FW）·h。光合作用增强（PAR和温度变化，主动）导致细胞内有机物质浓度增加、干燥过程导致细胞脱水（被动）或细胞外盐浓度降低（被动），都会导致渗透压差异增大，从而促进DOC释放。
