Faroe Shetland Channel Deep-sea sediment slurry incubation with oil hydrocarbons. The Variable Influence of Dispersant on Degradation of Oil Hydrocarbons in Subarctic Deep-Sea Sediments at Low Temperatures (0–5 °C)

The microbial degradation of petroleum hydrocarbons at low temperatures was investigated in subarctic deep-sea sediments in the Faroe Shetland Channel (FSC). The effect of the marine oil dispersant, Superdispersant 25 on hydrocarbon degradation was also examined. Sediments collected at 500 and 1000 m depth were spiked with a model oil containing 20 hydrocarbons and incubated at ambient temperature (5 and 0 °C, respectively) with and without marine dispersant. Treatment of sediments with hydrocarbons resulted in the enrichment of Gammaproteobacteria, and specifically the genera Pseudoalteromonas, Pseudomonas, Halomonas, and Cobetia. Hydrocarbon degradation was faster at 5 °C (500 m) with 65–89% of each component degraded after 50 days compared to 0–47% degradation at 0 °C (1000 m), where the aromatic hydrocarbons fluoranthene, anthracene, and Dibenzothiophene showed no degradation. Dispersant significantly increased the rate of degradation at 1000 m, but had no effect at 500 m. There was no statistically significant effect of Superdispersant 25 on the bacterial community structure at either station. These results show that the indigenous bacterial community in the FSC has the capacity to mitigate some of the effects of a potential oil spill, however, the effect of dispersant is ambiguous and further research is needed to understand the implications of its use www.nature.com/articles/s41598-017-02475-9

本研究以法罗-设得兰海峡（Faroe Shetland Channel, FSC）的亚北极深海沉积物为研究对象，探究了低温环境下石油烃类的微生物降解过程，同时考察了海洋石油分散剂Superdispersant 25对烃类降解的影响。研究人员采集了水深500米与1000米处的沉积物，向其中掺加含20种烃类的模拟石油，随后分别在对应原位温度（5℃与0℃）下，设置添加与不添加海洋分散剂的实验组进行孵育培养。向沉积物中引入烃类后，可检测到γ-变形菌纲（Gammaproteobacteria）的丰度显著富集，其中假交替单胞菌属（Pseudoalteromonas）、假单胞菌属（Pseudomonas）、嗜盐单胞菌属（Halomonas）与科贝特氏菌属（Cobetia）的富集效果尤为显著。5℃环境（对应500米水深）下的烃类降解速率更快：孵育50天后，各烃类组分的降解率可达65%至89%；而0℃环境（对应1000米水深）下的降解率仅为0%至47%，其中芳香烃类荧蒽（fluoranthene）、蒽（anthracene）与二苯并噻吩（Dibenzothiophene）未发生降解。海洋分散剂可显著提升1000米水深沉积物中的烃类降解速率，但对500米水深沉积物的降解过程无明显影响。此外，Superdispersant 25对两个采样站位的细菌群落结构均无统计学意义上的显著影响。上述结果表明，法罗-设得兰海峡的土著细菌群落具备缓解潜在石油泄漏部分危害的能力，但海洋分散剂的实际作用仍不明确，需开展进一步研究以明确其使用的潜在影响。本研究相关内容发表于：www.nature.com/articles/s41598-017-02475-9