Microbial communities present on mooring chain steels with different copper contents and corrosion rates

Copper has long been utilized as a disinfectant for bacteria,but its impact on microbial communities attached to the steel surface in seawater remains unknown.In the present study,3 mooring chain steels of different copper contents are subjected to a 3-month marine field exposure,and the corrosion rate increases in the order of BR5 steel(without copper)<BR5 CuH steel(0.8%copper)<BR5 CuL steel(0.4%copper).The microbial community results show that copper introduction does not result in an obvious change in microbial quantity,but it alters the diversity,richness,and structure of microbial communities due to the variation in copper-resistance of different species.BR5 CuH steel holds microbial communities with the highest percentage of some well-known corrosive microbes including sulfate-reducing bacteria,sulfuroxidizing bacteria,and iron-oxidizing bacteria,but possesses the lowest community diversity/richness owing to the toxicity of copper.The microbial community diversity/richness is stimulated by the low-copper content of BR5 CuL steel,and this steel also carries an intermediate proportion of such corrosive bacteria.Both well-known corrosive bacteria and microbial community diversity/richness seem to be involved in the corrosion acceleration of copper-bearing mooring chain steels.

生物炭肥对大棚番茄产量及土壤质量的影响

通过田间试验研究了生物炭肥对番茄产量及土壤质量的影响。结果表明,施用生物炭肥可有效提高土壤pH值,降低土壤酸度、降低土壤盐碱度,明显提高土壤有机质,能有效改善土壤理化性质。施用生物炭肥的处理,其番茄株高、茎粗,单株结果数、有效台数等性状明显优于常规施肥处理。