海水中碱性磷酸酶活力的测定及其在磷的循环中的作用初探

建立了海水介质中浮游植物、细菌及游离态三种碱性磷酸酶活力的分光测定法。在厦门西港海域及实验生态中分别测定了这三种碱性磷酸酶的活力;同时采用~(32)P示踪法探讨了碱性磷酸酶对小球藻直接利用溶解有机磷(DOP)的影响。结果表明,浮游植物体的碱性磷酸酶活力占主导地位;当水体溶解无机磷降低到一定浓度时,浮游植物体碱性磷酸酶活力可突增,它提供了浮游植物直接利用DOP的条件。

MEASUREMENT OF ALKALINE PHOSPHATASE ACTIVITY IN SEAWATER SUBSTRATES AND INVESTIGATION ON THE ROLE OF ALKALINE PHOSPHATASE IN THE CYCLING OF PHOSPHORUS

Spectrophotometric analysis of PAPA (alkaline phosphatase activity of phytoplankton), BAPA (bacteria alkaline phosphatase activity), and DAPA (dissolved alkaline phosphatase activity) in seawater substrate showed these three APA detected in Xiamen harbour seawater and in a laboratory culture system showed that phytoplankton is the major carrier of alkaline phosphatase, which implies the capability of directly utilizing dissolved organic phosphorus (DOP) of algaes. Radiophosphorus tracer study also demonstrated that Chlorella sp. can use biooriginal DOP. It was found that APA is stimulated only when the dissolved inorganic phosphorus (DIP) level in the seawater is low(especially when the PAPA increases dramatically) which provides the bioavailable phosphorus from DOP for phytoplankton growth when DIP is depleted. DAPA is relatively constant whether DIP is low or high, suggesting that the importance of regeneration of DIP from DOP through catalytic hydrolysis by dissolved alkaline phosphatase needs to be further studied.