红树林
环境化学
甲基汞
微生物
硫酸盐
Mercury(编程语言)
铁细菌
硫酸盐还原菌
沉积物
化学
甲基化
细菌
生态学
生物
生物累积
生物化学
基因
古生物学
遗传学
有机化学
程序设计语言
计算机科学
作者
Raquel Rose Silva Correia,Jean Remy Davée Guimarães
出处
期刊:Chemosphere
[Elsevier]
日期:2017-01-01
卷期号:167: 438-443
被引量:35
标识
DOI:10.1016/j.chemosphere.2016.09.153
摘要
Recent studies have shown Hg methylation in mangrove sediments, however, little is known about the different microorganism consortia involved. We investigated the participation of prokaryotes in general, iron-reducing bacteria-IRB, sulfate-reducing bacteria-SRB, methanogens and fungi in Hg methylation and sulfate reduction rates (SRR) in mangrove sediments using iron amendments for IRB and specific inhibitors for the other microorganisms. Sediment samples were collected from two mangrove zones, tidal flat and mangrove forest (named root sediments). Samples were incubated with 203Hg or 35SO42− and Me203Hg/35Sulfur were measured by liquid scintillation. Methylmercury (MeHg) formation was significantly reduced when SRB (87.7%), prokaryotes (76%) and methanogens (36.5%) were inhibited in root sediments, but only SRB (51.6%) and prokaryotes (57.3%) in tidal flat. However, in the tidal flat, inhibition of methanogens doubled Hg methylation (104.5%). All inhibitors (except fungicide) significantly reduced SRR in both zones. In iron amended tidal flat samples, Hg methylation increased 56.5% at 100 μg g−1 and decreased at 500 and 1000 μg g−1 (57.8 and 82%). In the roots region, however, MeHg formation gradually decreased in response to Fe amendments from 100 μg g−1 (37.7%) to 1000 μg g−1 (93%). SRR decreased in all iron amendments. This first simultaneous evaluation of Hg methylation and sulfate-reduction and of the effect of iron and inhibitors on both processes suggest that SRB are important Hg methylators in mangrove sediments. However, it also suggests that SRB activity could not explain all MeHg formation. This implies the direct or indirect participation of other microorganisms such as IRB and methanogens and a complex relationship among these groups.
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