Assoc. Prof. Dr. Xiaolei Liu 

Arsenic, a toxic element, can be found ubiquitously in the ocean. Surprisingly, certain bacteria have the ability to utilize arsenic minerals as a source of energy. Meanwhile, methane, a potent greenhouse gas with a warming effect much stronger than carbon dioxide, is often generated in marine sediment. However, the majority of methane produced is consumed by microbes that use sulfate as an oxidant. Recent studies have indicated that certain soil bacteria can also utilize arsenic minerals to oxidize methane, suggesting that this phenomenon may be widespread in marine environments as well. In fact, sediments with higher rates of methane oxidation have shown elevated concentrations of arsenic, potentially due to the activity of bacteria that consume both arsenic and methane. If confirmed, this could represent an overlooked mechanism for mitigating methane levels in the ocean. Unfortunately, the study of arsenic biochemistry in the environment is hindered by the absence of specific molecular tools. Recently, we have made a significant breakthrough by identifying a suit of arsenic-containing lipids known as arsenolipids, which are produced by bacteria that metabolize arsenic in marine sediments. In this proposed project, we aim to investigate whether these arsenolipids can serve as indicators for the occurrence of methane oxidation associated with arsenic biochemistry.