Royal Netherlands Institute for Sea Research
Phone number
+31 (0)222 36 9463
Research Leader
  • Biogeochemistry
  • Organic Geochemistry
  • Geomicrobiology
  • Marine isotope ecology & microbial food web structures
  • Degradation of 'unconventional' carbon substrates

Prof. Dr. Helge Niemann

Research Leader

‘The role of bacteria in breaking down methane … and plastic’

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.’

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I am intrigued by the transformation of important but ‘unconventional’ carbon substrates such as methane, oil and plastics and their fate in aquatic (microbial) food web structures. With the aid of a multidisciplinary approach, my research particularly focuses on the geomicrobiology (including organic biogeochemistry) and spatiotemporal aspects of aquatic carbon cycling and the turnover of unconventional carbon substrates in sediments and the water column. In addition, I am also interested in lipid biomarkers as chemotaxonomic markers, and proxy indicators recording (paleo) environmental conditions.

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Linked news

Monday 23 January 2023
Bacteria really eat plastic
The bacterium Rhodococcus ruber eats and actually digests plastic. This has been shown in laboratory experiments by PhD student Maaike Goudriaan at Royal Netherlands Institute for Sea Research (NIOZ). Based on a model study with plastic in artificial…
Wednesday 11 January 2023
Sunlight pulps the plastic soup
UV light from the sun slowly breaks down plastics on the ocean’s surfaces. Floating microplastic is broken down into ever smaller, invisible nanoplastic particles that spread across the entire water column, but also to compounds that can then be…
Friday 05 August 2022
Microbes don’t descend down with plastic particles into the deep sea
A bit of good news from the deep sea. Research has shown that microbes on floating plastic particles can be transported over long horizontal distances. New research carried out by Annika Vaksmaa (Royal Netherlands Institute for Sea Research NIOZ) and…
Monday 18 July 2022
Tons of nanoplastic floating in the Wadden Sea
In the Wadden Sea, there’s about 20 tons of polystyrene and another 5 tons of PET floating in the form of invisible nano and micro particles are. That's the figure UU and NIOZ researchers calculate this month in the journal Science of the Total…
Saturday 04 June 2022
Measurement project for methane from the North Sea seabed started
In several places, methane escapes from the seabed of the North Sea. Methane is a strong greenhouse gas and its emission into the sea and subsequent release into the atmosphere can contribute to global warming. Recent German research suggests that…
Tuesday 14 January 2020
Ice bubbles still hold methane in Arctic sediment during cold season
During parts of the year, the enclosure of gas hydrates causes the ocean floor around Svalbard to emit nearly half the amount of the greenhouse gas methane than previously thought. Warming of sea water might stop this seasonal difference during this…
Wednesday 24 April 2019
NIOZ North Sea expeditions 2019: Three Pelagia cruises to study the carrying capacity of the North Sea
On May 8th the first of three North Sea cruises to be held in 2019 under the flag of the NIOZ North Sea Research Centre (NIOZ-NSRC) has sailed off from Texel to investigate the North Sea. Each cruise lasts 2 to 3 weeks and will follow a different…
Friday 01 March 2019
Helge Niemann benoemd tot bijzonder hoogleraar Universiteit Utrecht
Dr. Helge Niemann is per 1 maart 2019 benoemd tot bijzonder hoogleraar 'Microbial and isotopic biogeochemistry' bij het departement Aardwetenschappen van Universiteit Utrecht. Niemann was hiervoor als senior wetenschapper al verbonden aan het…
Monday 22 October 2018
Speuren naar miljarden minuscule plasticdeeltjes in zee
Hoe onderzoek je de aanwezigheid en invloed van microplastics in onze estuaria, zeeën en oceanen? En: wat is de rol van microben bij het afbreken van deze fossiele of biologisch afbreekbare plastics? Het zijn vragen die dr. Linda Amaral-Zettler en…
Wednesday 10 October 2018
Fossiel celmembraan van bacterie bruikbaar voor klimaatonderzoek
Een 'paleo-thermometer' om klimaatschommelingen op land te meten is weer een stap dichterbij gekomen. Onderzoekers van onder meer het Koninklijk Nederlands Instituut voor Onderzoek der Zee (NIOZ) publiceren hierover deze week in het wetenschappelijk…

Linked blogs

Tuesday 28 November 2023
NIOZ@SEA | Cruise PE-527 Nanoplastic in the North Atlantic
Ocean plastic debris has been recognised as a severe environmental problem in the ocean but we are only beginning to understand the role of particles
Monday 23 October 2023
Methane emission in the North Sea II
Methane escapes from the seabed of the North Sea in various places. Recent German research suggested that this mainly occurs in the vicinity of abandoned wells. Methane is a potent greenhouse gas and its release into the sea and subsequent release…
Wednesday 11 November 2020
NIOZ@SEA | Cruise 64PE480: In search of Atlantic Nanoplastic
The overall goal of the cruise is to determine the total amount of plastic (macro, micro and nano) along a transect from the Azores through the N-Atlantic subtropical gyre and then towards the European shelf, English Channel and S-North Sea. The…
Monday 07 October 2019
NIOZ@SEA | North Sea Expedition PE462
In 2019 three Pelagia cruises are organised to study the carrying capacity of the North Sea. Each cruise will last 2 to 3 weeks and follows different routes to cover and describe the various parts of the ecosystem of the North Sea. Follow the blog of…
Friday 20 July 2018
Hidden secrets in the North Sea: An expedition addressing sea-level rise, oxygen loss and microbial breakdown of methane
The North Sea still hides many secrets. A joint team of researchers from the Royal NIOZ Sea Research, TNO, Deltares, Utrecht University and VU University Amsterdam set out on an expedition with the research vessel Pelagia to answer some questions…

NIOZ publications

Linked projects

NSME_North Sea Methane Emissions
Gert-Jan Reichart
Project duration
1 Jan 2022 - 31 Dec 2025
Plastic in the Ocean: Microbial Transformation of an ‘Unconventional’ Carbon Substrate
Helge Niemann
European Community || European Research Council
Project duration
1 Jun 2018 - 31 May 2023
UUNIOZ_Nanoplastics pollution in the Ocean
Helge Niemann
Utrecht University
Project duration
1 Jan 2021 - 31 Dec 2025