| In this study,mangrove sediments from the Gaoqiao Mangrove Nature Reserve in Zhanjiang were collected.The physiological and biochemical indexes of the sediments,the abundance of microbial functional genes and the microbial community structure were determined by functional gene quantification technology and 16 S r DNA high-throughput sequencing technology.The effects of rhizosphere oxidation on the dynamic changes of sediment nitrogen under different tidal levels were studied.The results showed that with the increase of the tidal level at the sampling point,the nutrient conditions of the sediments gradually improved,and the nutrient status of the rhizosphere sediments was better than that of the non-rhizosphere sediments.The nitrification intensity and nitrification function gene abundance of low tide sediments are higher than that of high tide deposits,and the denitrification intensity and denitrification function gene abundance of high tide deposits are higher than low tide deposits.From the perspective of microbial community structure,Avicennia marina as a pioneer species has higher abundance of nitrogen and phosphorus circulating functional microorganisms in rhizosphere sediments than other sampling points.The nitrogen,phosphorus and sulfur cycle function microbial abundance of rhizosphere sediments of Avicennia marina is higher than that of non-rhizosphere sediments.In the study of the life activities of mangrove bottom crabs,it was found that the activities of crabs directly promoted the nitrification process of sediments.Therefore,we believe that the rhizosphere effect of mangrove plants affects the absorption and utilization of nitrogen,and the synergistic effect of rhizosphere functional microorganisms also enables mangrove plants to survive in the intertidal weak nutrient environment.This is the adaptation of plants to harsh environments during long-term evolution,it is because of that adaptations they have a unique mangrove ecosystem. |
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