摘要:
以来自广西上林县大龙洞岩溶水库中的小球藻为研究对象,探讨了封闭体系中小球藻在4.6 mmol·L-1、2.5 mmol·L-1和0.5 mmol·L-1三种不同HCO3-浓度的水体环境中,对Ca2+和HCO3-的利用效率.结果表明:(1)小球藻在4.6 mmol·L-1、2.5 mmol· L-1和0.5 mmol·L-1三种不同HCO3-浓度的水体中培养7天后生物量从0.04Abs分别增长到0.56Abs、0.50Abs和0.44Abs,在HCO3-和Ca2+浓度较高的环境中,A组28.26%的Ca2+和B组24.14%的Ca2+被小球藻吸收利用,A组54.95%的HCO3-和B组48.00%的HCO3-被小球藻吸收利用,生成有机碳固定下来,C组HCO3-浓度过低(0.5 mmol·L-1),小球藻难以对其进行利用,表明岩溶水库中高浓度的HCO3-对小球藻生长起着“施肥作用”,这对岩溶碳汇的稳定性起着重要作用.(2)小球藻光合作用利用HCO3-从而引起Ca2+沉积的量大于小球藻光合作用吸收Ca2+的量;(3)小球藻光合作用使培养基中的δ13CDIC偏正,而呼吸作用使培养基中的δ13 CDIC偏负.
Abstract:
Chlorella was collected from Dalongdong cave in Shanglin county of Guangxi to study its utilization efficiency of Ca2+ and HCO3-in three water bodies with different concentrations of DIC (4.6 mmol · L-1,2.5 mmol· L-1 and0.5 mmol· L-1) in the closed system.The results show that:(1)After7 days of cultivation in three different DIC solution of 4.6 mmol · L-1、2.5 mmol · L-1 and 0.5 mmol · L-1,Chlorella biomass increased from 0.04 Abs,to 0.56 Abs,0.50 Abs and 0.44 Abs,respectively.In the environment with high HCO3-and Ca2+ concentration,Chlorella absorbed 54.95% of HCO3-in group A and 48.00% of HCO3-in group B,it also absorbed 28.26% of Ca2+ in group A and 24.14% of Ca2+ in group B.In the environment with low HCO3-concentration,it was difficult for Chlorella to absorb HCO3-in group C (0.5 mmol · L-1).These findings indicate that the high concentration of HCO3-in karst reservoirs plays a role of "fertilization" on the growth of Chlorella,which is significant to the karst process-related carbon sink;(2)The amount of Ca2+ deposition caused by Chlorella photosynthesis using HCO3-was higher than the amount of Ca2+ absorbed by Chlorella photosynthesis;(3)Photosynthesis from Chlorella make δ13CDIC positive,while the respiration make δ13CDIC negative in the culture medium.
下载: