岩溶水生环境富含$\mathrm{HCO}_{3}^{-}$,有利于内源藻类发生生物碳泵作用,形成大量藻源有机质沉积到库底。丰富的藻源性有机质在沉积物中发生矿化作用,影响有机质埋藏过程,影响岩溶水生环境碳循环过程和碳汇潜力。为探究藻源性有机质对矿化作用的影响和岩溶水生环境碳循环稳定性的影响,以岩溶地下水补给型水库(广西大龙洞水库)为研究对象,初步分析从上游到下游不同区域藻源有机质对表层沉积物有机质矿化过程的影响。结果表明:大龙洞水库有机质主要来源为内源藻类(20.9%~65%)和外源土壤(11.8%~53.4%)且具有一定的空间差异,水库上游以土壤来源为主,下游以藻类来源为主。大龙洞水库表层沉积物矿化过程在空间上呈现上游潜在矿化量高于下游潜在矿化量,产生差异的主要因素是在岩溶高溶解无机碳水环境中,藻源性有机碳对微生物矿化过程具有抑制性,降低矿化强度。在生物碳泵作用和无机碳保护下,以藻源性来源为主的岩溶水库表层沉积物有机碳潜在埋藏总量略高于岩溶区土壤的潜在埋藏总量,表明岩溶水库沉积物有着稳定的有机成分积累。

In the karst reservoir, there are a lot of $\mathrm{HCO}_{3}^{-}$ in the water column, which can promote algae to function of biological carbon pump and lead the algae organic matter to be deposited under the water column. Meanwhile, algae organic matter is mineralized on the sediment suffer in order to affect the organic matter burial, carbon cycle of karst aquatic environment. To study effect and of algae-derived organic matter source on sediment mineralization, we selected the Dalongdong Reservoir as the object and analyzed carbon cycle stability of karst reservoir aquatic environment. The results revealed that: organic carbon in the surface sediment come from the algae source (20.9%-65%) and soil source (11.8%-53.4%), which organic carbon of algae source was mainly deposited on the downstream and soil source' was on the upstream. The potential mineralization on the upstream was higher than that on the downstream, because the mineralization process of organic carbon was influenced by organic source difference, especially algae-source; with biological carbon pumping effect and inorganic carbon protection, potential burial volume in the surface sediment of karst reservoir was higher than that in the karst soil, which showed that sediment structure in the karst reservoir was stable.