易分解碳输入模式对沉积物共代谢效应的影响

The co-metabolism effect of lake sediments input pattern of labile carbon

通过构建室内微宇宙系统,运用稳定碳同位素示踪法,解析混合处理组中各有机组分代谢释放的CO2含量,探讨相对易分解碳源的输入对湖泊沉积物有机碳矿化过程的影响.结果表明:添加相对易分解碳源的处理组中,CO2排放量明显升高,较对照组分别提高了45.49%(单次添加组)、52.61%(重复添加组)和57.65%(连续添加组),分次添加模式明显造成更高CO2排放量.各组中由沉积物矿化产生的CO2排放量较对照组分别提高了16.92%(单次添加组)、24.26%(重复添加组)、27.40%(连续添加组).尽管不同添加模式下,各组均表现为正向共代谢效应(即促进沉积物有机碳分解),但在培养结束时整体有机碳含量均净增加.葡萄糖促进了沉积物有机碳的矿化能力,但对自身代谢影响较小.考虑到富营养化湖泊中藻类的爆发频次和范围都进一步增加,藻类碎屑源源不断激发的共代谢效应不可忽略,在一定程度上削弱了湖泊沉积物的“碳汇”功能.

The microcosm system was constructed to analyze the CO2 release during the metabolism processes of organic components in the mixed treatment by using the stable carbon isotope tracer.The influence of the labile carbon addition on the decomposition process of organic carbon in lake sediments was also explored.The results showed that:Compared with the control,the CO2 emissions in the treatment with labile carbon addition increased by 45.49% for single addition treatment(ST),52.61% for repeated addition treatment(RT)and 57.65% for continuous addition treatment(CT),respectively.The CO2 emissions from sediments in each treatment increased by 16.92%(ST),24.26%(RT)and 27.40%(CT)than the control,respectively.Although the positive co-metabolic effect(promoting the decomposition of organic carbon in sediments)was observed in each treatment under different addition modes,the net organic carbon content increased at the end of culture.Glucose promoted the mineralization of organic carbon in sediments,but had little effect on its own metabolism.Considering that the outbreak frequency and range of algae in eutrophic lakes are further increased,the co-metabolism effect triggered by the continuous input of algae organic detritus cannot be ignored,which weakens the function of carbon sink of lake sediments.