低盐度形成的微生物膜对厚壳贻贝稚贝附着的影响

Settlement of the mussel Mytilus coruscus plantigrades in response to biofilms formed on low salinities

为研究环境因子在厚壳贻贝(Mytilus coruscus)稚贝附着过程中的调控作用,作者探讨了低盐度对微生物膜生物构成、群落结构的影响及所形成微生物膜对厚壳贻贝稚贝附着的影响。在实验室条件下,研究微生物膜的日龄与干质量、细菌密度和硅藻密度、叶绿素a含量的关系及其对厚壳贻贝稚贝附着的影响。通过DGGE指纹图谱技术对微生物膜中的细菌群落结构多样性进行了分析。研究发现,盐度13和23时形成的微生物膜能有效促进厚壳贻贝稚贝的附着,且盐度23、28 d时稚贝附着率最高,达到72%。相关性分析表明,微生物膜的诱导活性与盐度、干质量、细菌密度、硅藻密度、日龄呈显著正相关性,与叶绿素a无相关性。微生物膜的干质量、附着细菌密度及底栖硅藻密度明显随着日龄的增加而增加,叶绿素a含量与微生物膜日龄无显著相关性。细菌群落在厚壳贻贝稚贝附着过程中发挥重要调控作用。

The influence of low salinity formed biofilms on the settlement of the plantigrade Mytilus coruscus was investigated in the laboratory. Various aspects of biofilms were examined including age, dry weight, chlorophyll a concentration, bacterial and diatom densitie. The diversity of bacterial community structure was analyzed by fin- gerprint technique DGGE. It is found that the settlement of M. coruscus was promoted by the biofilms which are formed when the salinity is 13 or 23. Furthermore the adhesive rate reached maximum value 72% when the salinity is 13 or 23. It is indicated that the inducing activity of biofilm was positively correlated with salinity, biofilm age, dry weight and bacterial and diatom densities, but uncorrelated with chlorophyll a concentration. The dry weight, bacterial densities and diatom densities in biofilm increased with biofilm age, but chlorophylla was uncorrelated with biofilm age. Overall, this investigation indicates that bacterial structure may play an important role in the ad- hesion of the plantigrade M. coruscus, which can be induced by low salinity formed biofilms.