微生物活动对富营养化湖泊底泥磷释放的影响

Effects of Microorganisms on Phosphorus Release from Sediment of Eutrophic Lake

目前,影响内源磷释放的物理、化学因素已有较为系统的研究,而微生物对磷释放的影响一直以来并未有确切的结论。针对上述问题,文章首先研究能够有效抑制水体微生物增殖的方法,并建立了能有效控制微生物活性的对照模型,在此基础上进一步研究微生物的存在对底泥磷释放的影响。结果表明,按50 mg/L添加量分别加入铜、铬和镉3种重金属离子,无法抑制上覆水中微生物的活性,而40%的甲醛溶液是较好的微生物抑制剂;当底泥和上覆水中微生物数量增加时,微生物的活动会导致泥水界面氧化还原电位降低,同时细菌代谢过程产生的酸类会溶解底泥中难溶的磷酸盐,从而促进底泥磷的释放,释放量可达底泥总磷原有含量的20.11%;反之,底泥会吸附上覆水中的磷,增加量占底泥原有总磷的15.02%。

The physical and chemical factors of endogenous phosphorus release have been so far systemically studied;however,the effect of microbes is still open to debate. This laboratory study elaborated on a method that inhibits microbial proliferation in overlying water;at the same time,an effective model was established for controlling microbial activity to better understand phosphorus release under the influence of microbes. The results showed that metal ions of copper,chromium and cadmium,which were added into the overlying water（50 mg/L each）,were unable to inhibit the microbial activity,but 40% formaldehyde solution in place of metal ions worked effectively. Moreover,TP released from the sediment may account for 20.11% of the original TP content in sediment because of the facts that microbes reduced the ORP and produced acids in the metabolic process to dissolve the insoluble phosphate in sediment. Otherwise,sediment could absorb phosphorus from overlying water with an increment accounts for 15.02% of the original TP in sediment.