Study On The Relationship Between Environmental Factors And Diversity Of Bacterioplankton In Different Oxygen Content Regions Of The Eastern Indian Ocean

The oxygen content of seawater affects the composition and function of marine ecosystems.The decrease of dissolved oxygen content leads to changes in biogeochemical cycle processes and functions,and the structure and function of microbial communities also change.In recent years,the expansion of the oceanic oxygen minimum zones(OMZs)has made it a hotspot in global biogeochemical research.The changes in chemical flux and microbiological characteristics in OMZs have also become the focus of research in the low-oxygen zone.The Bay of Bengal(BB)hypoxic zone is one of the major hypoxic regions in the world,but little is known about the distribution and ecological functions of bacterioplankton in the region.This thesis focuses on the East Indian Ocean as the research object,and carries out water sample collection work for sites with different depths in 22 different sites in 5 different regions.The environmental factors such as dissolved oxygen,temperature,salinity and nutrients in this region have been carried out.The relationship between bacterial abundance,bacterial diversity and environmental factors in different oxygen-containing regions was compared and analyzed.The results show that the environmental factors of the East Indian Ocean are more distinct with geographical location,showing a certain regularity.In addition,the results reveal the existence of another OMZ in the East Indian Ocean except the previously reported one in the Bay.In the study of the relationship between bacterial abundance and its environmental factors,the relationship between the two was significant,and the abundance of bacteria was significantly positively correlated with temperature and dissolved oxygen,and negatively correlated with salinity and silicate content.It noted the special relationship between silicate and bacterial abundance in this area.The bacterial diversity analyses indicated that the community composition of planktonic bacteria in the East Indian Ocean mainly changes with the depth at the phylum level,while the difference in horizontal space is relatively small.