不同浓度碳源下中肋骨条藻和海洋异养细菌对磷酸盐的竞争吸收研究

Competition and Uptake between Skeletonema Costatum and Heterotrophic Bacteria for Phosphate

采用实验室一次性培养法,在设定的不同有机碳浓度(0,27.5,275 mmol/L)和无机磷酸盐浓度(0.3,1,2μmol/L)条件下,选用天然海水中的异养细菌和中肋骨条藻进行混合培养,研究菌、藻的生长情况和对营养物质的吸收,探讨菌、藻对无机磷的竞争关系。在外源有机物的浓度分别为27.5,275 mmol/L下,细菌前两天比生长速率的平均值分别为0.66/d和0.73/d,相对不加有机碳组的0.53/d明显增大,其指数生长主要在培养开始的1~2 d,而藻类则在第3天后开始指数生长。随着无机磷酸盐浓度的增加,藻密度、细菌丰度和其对磷酸盐的吸收量都有所增加。在低浓度磷下,外源碳的加入对于藻细胞吸收磷有影响;高浓度磷(】1μmol/L)下,外源碳的加入对于藻细胞吸收磷几乎没有影响。

Marine heterotrophic bacteria and Skeletonema costatum(Greville)Cleve from natural seawaters are incubated on different organic carbon(0,27.5,275 mmol/L) and inorganic phosphate concentrations(0.3,1,2 μmol/L).The interactions of heterotrophic bacteria and Skeletonema costatum to the nutrient elements are discussed,while the competitions between algae and bacteria to inorganic phosphate are explored.In the presence of an external carbon source,the growth rates of heterotrophic bacteria averages 0.66/d and 0.73/d,higher than the treatments without glucose additions 0.53/d.Exponential growth of bacteria appeares 1～2 days while algae after 3rd days.As inorganic phosphate concentration increased,algal cell density,bacterial abundance and P-uptake also increases.At low phosphate concentrations,external carbon source has some influence on algal P-takeup.At high concentrations,algal P-takeup is hardly affected by organic carbon additions.