光照与氮磷营养盐的协同作用对海带幼苗释放可溶性有机碳的影响  

SYNERGETIC EFFECT OF LIGHT AND NUTRIENTS ON THE RELEASE OF DISSLOVED ORGANIC CARBON FROM JUVENILES OF SACCHARINA JAPONICA

作　　者：尼志杰 张永生 褚洪永 李斌 张明亮 孙琰晴 胡顺鑫 NI Zhi-Jie;ZHANG Yong-Sheng;CHU Hong-Yong;LI Bin;ZHANG Ming-Liang;SUN Yan-Qing;HU Shun-Xin(College of Fisheries and Life,Shanghai Ocean University,Shanghai 201306,China;Shandong Marine Resource and Environment Research Institute,Yantai 264006,China;Rongcheng Marine and Fishery Law Enforcement Unit,Weihai 2643002,China;Yantai Marine Economic Research Institute,Yantai 264003,China)

机构地区：[1]上海海洋大学水产与生命学院,上海201306 [2]山东省海洋资源与环境研究院,烟台264006 [3]荣成市海洋与渔业执法大队,威海264300 [4]烟台市海洋经济研究院,烟台264003

出　　处：《水生生物学报》2022年第12期1909-1915,共7页Acta Hydrobiologica Sinica

基　　金：国家自然科学基金(42176159);烟台市科技创新发展计划项目(2020MSGY059)资助。

摘　　要：文章以海带(Saccharina japonica)幼苗为实验材料,对比了其在自然海水+50%海面光强、自然海水+100%海面光强、营养盐加富海水+50%海面光强、营养盐加富海水+100%海面光强4种条件下的溶解有机碳(DOC)释放速率,以揭示光照与营养盐的协同作用对大型藻类释放DOC的影响机制。研究发现,在自然海水条件下,50%与100%海面光强照射下海带幼苗DOC释放速率分别为(11.67±3.07)和(22.65±4.58)μmol/(g·h),随着光强增加,释放DOC速率显著提升(P<0.05),氧气净释放速率显著增大(P<0.05),且二者光谱斜率差异显著(P<0.05);在营养盐加富海水条件下,50%与100%海面光强照射下海带幼苗DOC释放速率分别为(30.88±7.96)和(39.03±14.78)μmol/(g·h),随着光强增加,释放DOC速率提升不显著(P>0.05),氧气净释放速率显著提高79.24%(P<0.05),二者光谱斜率差异不显著(P>0.05)。结果表明,在寡营养条件下(自然海水),海带幼苗释放DOC速率与光照强度呈正相关,表现为“溢出”机制;在富营养条件下,海带幼苗释放DOC速率与光照强度不相关,表现为“扩散”机制。海带幼苗释放DOC同时受到“溢出”和“扩散”两种机制的调控,何种机制占主导取决于营养水平。Macroalgae farming is an essential part of offshore carbon sink.Large-scale macroalgae farming promotes the absorption of atmospheric CO_(2) by the ocean.As the primary producer of marine ecosystems,macroalgae can convert Dissolved Inorganic Carbon(DIC)into Organic Carbon(OC)through photosynthesis.Macroalgae can also release 20%—30%of photosynthesis products into seawater in the form of Dissolved Organic Carbon(DOC).According to estimates,the total amount of DOC released by macroalgae farming in China is about 822000 to 915000 tons,which can be transformed into 600000 tons of Recalcitrant Dissolved Organic Carbon(RDOC)every year through the action of Marine Microbial Carbon Pump(MCP).Therefore,seaweed culture plays a vital role in fisheries carbon sink.However,the synergistic effect of light and nutrients on DOC release by algae is still controversial.There are currently two hypotheses.One is the“overflow”hypothesis.Fogg believed that DOC release from algae was positively correlated with light intensity,which promoted the release of high molecular weight storage products.In Cherrier’s laboratory and field studies,the DOC release rate of planktonic algae was positively correlated with light intensity.After studying multiple experimental data on benthic algae,Barrón also found that the net DOC flux of benthic algae was positively correlated with light intensity.These reports show a significant correlation between light intensity and DOC release rate.Another hypothesis is“diffusion”.Bjornsen believes that the release rate of DOC from algae has nothing to do with light,but is closely related to the nutrient concentration.Nutrients promote the release of dissolved low molecules substances in al-gae.In Marañón’s algae culture experiment,there was no correlation between DOC release and light intensity.In the cross-experiment of light and nutrients carried out by Mueller,the correlation between DOC release of coral symbiotic algae and light disappeared when nutrients were added.The above studies show tha

关 键 词：溶解有机碳 溢出机制 扩散机制 碳汇渔业 海带 

分 类 号：Q178.1[生物学—水生生物学]