Prof. Dr. Helge Niemann

Biogeochemist Prof. Helge Niemann studies the role of bacteria and other microorganisms in the breakdown of both methane and plastic. The present era of massive anthropogenic environmental change puts the ocean under pressure. Marine systems play a key role in the cycling of potent greenhouse gases such as methane, thereby keeping the Earth’s climate at its current habitual conditions. On the other hand, the ocean is swamped with pollutants such plastics. At a first glimpse, Methane and plastics don’t seem to have a lot in common. However, when examining their molecular structures it becomes obvious that they share some important chemical characteristics. Methane is the simplest hydrocarbon, while plastics are very complex hydrocarbons or hydrocarbon-like compounds. Key concepts related to the degradation of methane might thus apply for plastics, as well.

Methane as a source of energy or a source of problems

‘In deep waters, microorganisms manage to capture and decompose much of the methane. In shallow seas, such as the Wadden Sea, that scarcely happens. I am trying to discover under which specific circumstances bacteria can decompose methane and how much is still contained in the seafloor. On the one hand, countries like Japan and India are already investigating possibilities to extract methane from the ocean floor as a source of energy. On the other hand, that methane in the ocean floor is also a potential problem, because increasing amounts of it will be released due to global warming. That could further accelerate the warming of our climate.’

Do microbes eat plastic?

‘Microbes may also play a major role in the balance of plastic in the oceans. Of the estimated 320 million tonnes of plastics that might have ended up in the oceans since the 1950s, only ~1% is found afloat at the surface. Where is the remainder? In our experimental research, we are feeding bacteria and other microorganisms with plastic particles under differing climatological conditions to discover whether those organisms feed on plastics and could thus play a role in plastic degradation in the ocean. Also, we examine the role of physical and chemical processes on the decomposition of plastic. To fully understand the  problems of ocean plastic pollution, we need to have a better knowledge about the fate of plastic in the marine realm.’