Vacancies – available projects

The positions are organized in 5 research themes – please click on a research theme for more information about the available positions within that theme. During the first call for applications a number of the available positions were filled. At the moment, the second call is open for the 13 non filled positions.

If you have any questions regarding a specific project please contact the project supervisors directly. When you have any practical questions please contact the NESSC office.

When applying take the maximum of 3 projects into account that can be applied for. Please write one motivation letter and motivate your choices for the various projects clearly. Submit the letter to every project you are applying for separately. If you apply for more than 3 projects, please note that we cannot consider all applications (e.g. we will only take three into account).

The application deadline is 31/10/2019, the expected enrolment January-March 2020.

Research theme: Greenhouse gas sources and sinks - Five available positions coming up


Increasing greenhouse gas concentration are the cause of climate change and their sinks and sources are not well constrained and changing because of climate change

Title:  Multiple extreme events in the sub-Arctic
Project description: Climate change is increasing the frequency and intensity of extreme events in many regions of the world. This can have large impacts on species, the communities they are part of and the processes within ecosystems. If hit hard enough, ecosystems may even be pushed into another state. Extreme events during the growing season are likely to have direct impacts on species survival and growth but an extreme winter even may just as well have lasting impacts on the following growing season.
Summer drought, heat events and fire have received particular attention in the Arctic region as well as extreme winter warming events and rain on snow events. However, the combination of extreme events during winter and summer has received relative little attention despite the fact that both events are likely to occur in the near future and will very likely acerbate each other’s impact on species, communities and ecosystems processes.  Considering the current changes in Arctic vegetation, shrubification and permafrost melting, observed as a result of climate warming and the feedback this has on the global carbon cycling and weather patterns there is an urgent need to address the impact of multiple extreme events.
This project will consist of a mixture of field experiments in sub-arctic Scandinavia (mainly the Abisko area) and mesocosm experiments in Amsterdam under controlled conditions. However, there is a considerable amount of freedom within the project, so the position is flexible with regard to focus on plot scale experiments to landscape scale natural events. The focus will be on the effects of extreme events on plant community development, ecosystem processes (carbon and nutrient fluxes, using amongst others 13C and 15N labelling), and on invasive species. The exact focus will among various others depend on the expertise of the candidate.
Supervisors: Aerts (VU-Ecology), Dolman (VU-Earth Sciences), Bokhorst
Host institute: VU (Ecology)
Background/expertise: Good background and affinity in Arctic terrestrial ecology and with expertise in biogeochemical analyses and preferably also in microbial ecology, willing to address the impact of multiple extreme events on sub-Arctic ecosystems.
– Please click here to apply –

Title: Methane cycling microorganisms in changing Arctic ecosystems
Project description: Arctic permafrost soils store large amounts of organic matter that is sensitive to temperature increases and subsequent microbial degradation to methane (CH4) and carbon dioxide (CO2). In Arctic ecosystems CH4 contributes to up to half of the expected climate forcing when taking the global warming potential into account. The goal of this project is to study the dynamic landscape scale fluxes and the microbial mechanisms that underlie the contributions of the Arctic to the global greenhouse gas budget. The linkage between the actual microbes and landscape scale fluxes, however, is elusive. This project will use a combination of microbial analysis by the PhD student studying methanogenic and methanotrophic activity and community composition in selected pan-Arctic samples under in situ temperature conditions (4°C) and the IPCC 2013 Arctic climate change scenario (10°C). Activity studies will be carried out with and without addition of methanogenic and methanotrophic substrates to stimulate methane cycling activity, and sample and data collection and interpretive modelling will be carried out at the VU.
Supervisors: Dolman (VU-Earth Sciences), Jetten (RU)
Host institute: VU (Earth Sciences), frequent travel to NESSC institute RU is expected
Required background/expertise: Master’s degree in Earth Science or microbiology with an affinity for geoscience
– Please click here to apply –

Title: Methane cycling micro-organisms and greenhouse gas fluxes in coastal sediments
Project description: Coastal sediments are vulnerable ecosystems threatened by various kinds of pollution, and harbor a complex microbial  community and biogeochemistry that is hardly explored. With a warming  potential that is 34 times higher than CO2, methane (CH4) is a  significant contributor to the global greenhouse effect. The balance  between CO2 and CH4 emissions, which is steered by the microbial methane  cycling community, has therefore a major impact on global warming. This  warming will have stimulating effect on both methane-producing
(methanogenic) and methane-consuming (methanotrophic) microorganisms.  However, since different microorganisms are differentially affected by  these changes, the effects on net greenhouse gas (GHG) fluxes remain  elusive. Within this project you will study the in situ methanogenic and  methanotrophic activity and community composition in situ. You will also  study the methane cycling activity in controlled laboratory settings.  Suitable samples will be used for enrichment of novel microorganisms.  The data will be used as input for new global gene-based models.  Sampling campaigns with NESSC partners to suitable field sites will be  part of the PhD study.
Supervisors: Jetten (RU)
Host institute: RU
Required background/expertise: microbiology, aquatic ecology, geobiology
– Please click here to apply –

Title: Interactions of nitrogen- and methane-cycling microorganisms in lab scale bioreactors mimicking coastal sediments
Project description: Microorganisms are the drivers of biogeochemical  nitrogen and carbon cycles. These elemental cycles are interconnected by  the activity of different microbial guilds in sediments of coastal  ecosystems. Essential roles of chemolithoautotrophic microorganisms  provide a tight balance in the local and global bioavailable carbon and  nitrogen budget. In a rapidly changing world, the nutrient cycles are  shifting and might reach tipping points that result in irreversible  ecosystem changes. One of the most significant links between the  nitrogen and carbon cycle is found in anaerobic methanotrophic  ecosystems. In these ecosystems, the methane can be oxidized by  anaerobic microorganisms that use nitrate or iron-oxides as electron  acceptor. There is no clear consensus on the contribution of coastal to  the global CH4 budget, since because source magnitude and variability  are largely unknown. In this project you will investigate a
nitrate‐reducing microbial community in a laboratory‐scale bioreactor  model that closely mimicks estuary or brackish sediment conditions. The  data will be used to improve our understanding on greenhouse gas fluxes  from brackish coastal sediments. Sampling campaigns with NESSC partners  to suitable field sites will be part of the PhD study.
Supervisors: Jetten (RU)
Host institute: RU 
Required background/expertise: Microbiology, aquatic ecology, geobiology, life sciences
– Please click here to apply –

Title: Constraining past atmospheric methane concentrations using biomarker lipids of methanotrophs
Project description: Methane is an important greenhouse gas and modern atmospheric methane concentrations are rising. However, the role of methane in past climate change is essentially unknown, due to a lack of quantitative proxies. This project will validate several potential organic proxies for methane oxidation by constraining their occurrence and their relationship with environmental variables, such as atmospheric methane concentration and temperature. This work will involve incubations of methanotrophs with a focus on validating organic biomarkers for past methanotrophy. Furthermore, we will analyze sedimentary archives from time periods where atmospheric methane concentration was thought to be elevated.
Supervisors: Schouten (NIOZ), Hopmans, Rush
Host institute: NIOZ
Required background/expertise:(organic) geochemistry, stable isotopes, earth sciences, analytical chemistry
– Please click here to apply –

Research theme: Land-ocean transfer: No available positions

Research theme: Ocean carbonate system dynamics - Two available positions coming up

About 25% of the anthropogenic carbon ends up in the ocean, with the consequences that is uptake capacity is declining. This theme aims to further our capabilities to quantify this

Title: Elucidating the global carbon cycle over the Cenozoic
Project description: Rock weathering consumes carbon dioxide and generates ions and alkalinity. After transport to the ocean, these products combine to form (biogenic silica and) carbonate minerals, which are eventually removed by burial in marine sediments. Over geologic time the balance between weathering and carbonate burial exerts a major control on seawater composition, atmospheric carbon dioxide and thus climate. This PhD project aims to elucidate past global carbon cycling via the reconstruction and modelling of past weathering intensities, ocean carbonate burial and other processes impacting atmospheric carbon dioxide and ocean alkalinity over geological timescales.
Supervisors: Middelburg (UU-GEO), Sluijs (UU-GEO)
Host institute: UU-GEO
Required background/expertise: We are looking for an Earth (System) scientist interested in developing conceptual and simple numerical models to creatively utilize the various records available and generate records where necessary.
– Please click here to apply –

Title: Developing new methods for reconstructing ancient PCO2 concentrations
Project description: Reconstruction of the past oceanic carbonate system remains an important challenge in Earth System Sciences. The stable carbon isotopic composition of crenarchaeol, the biomarker lipid of Thaumarchaeota, has the potential for reconstructing the 13C of Disolved Inorganic Carbon (DIC) and PCO2 in sediments where carbonates are poorly preserved. However, for this novel GC based methods need to be developed to analyse the isotopic composition of crenarchaeol. In this project we will develop this new methodology and apply it to cultures, modern environmental samples and core top and sediment core samples. Together with the 13C content of other (general) biomarker lipids, this method could yield reliable paleo PCO2 reconstructions, also in areas and time intervals where carbonates are absent. The new methodology will also be used for other compounds and isotope systems to develop new proxies.
Supervisors: Schouten (NIOZ), van der Meer
Host institute: NIOZ
Required background/expertise: MSc in geochemistry, stable isotopes, earth sciences, analytical chemistry
– Please click here to apply –

Research theme: Climate dynamics - Four available positions coming up

Understanding climate dynamics requires integration across temporal scales. This theme aims to link geological and historical record with mechanistic climate dynamic modelling

Title: Physics of the Mid-Pleistocene transition in a coupled climate, ice sheet carbon cycle model
Project description: During the Mid-Pleistocene the dynamics of the climate system changed from ice age cycles with a duration of 40 kyr towards cycles of 100 kyr which have a much larger amplitude as well. This has been recorded in ocean sediments and partly in ice cores. The transition took place without a direct change in the external radiative forcing which follows from the changes in Earth orbit. Hence, a combination of processes and feedbacks must have caused the transition. In this project we want to unravel the contribution of possibly mechanisms related to the role of the major ice sheets in the climate system or gradual changes in the CO2 concentration in the atmosphere. In order to do so we will use a hierarchy of climate models and perform transient simulations over the Mid-Pleistocene, where models will range from intermediate complexity models to full Earth system models. The project will improve our insights in climate sensitivity on long time scales.
Supervisors: van de Wal (UU-SCIENCE), Lourens (UU-GEO)
Host institute: UU-SCIENCE
Required background/expertise: (geo-) physics
– Please click here to apply –

Title: Probing paleoceanographic proxies in the Mediterranean Sea
Project description: Numerous paleoceanographic proxies have been developed and validated of the past decades based on several proxy carriers. Many of these proxy carriers, including calcitic planktic foraminifera and coccolithophores, siliceous diatoms, and organic biomarkers and dinoflagellate cysts are produced in the surface ocean. Their species distribution and chemical composition record physical, chemical and biological parameters of the surface ocean. However, for many of these proxy carriers, the exact depth of production, mechanisms and seasonality of export towards the seafloor and potential changes during export and briefly after deposition in the sediments remain unclear, very often implying unconstrained errors in the proxies.
In this project, we are looking for a highly motivated PhD candidate who will generate a mechanistic understanding of the processes involved between production and burial of the most important proxy carriers. The basis will be a unique and remarkably long ongoing time series of sediment trap material from the Mediterranean Sea. The PhD candidate will analyze the broad composition of the material as well as the chemical composition of various biogenic (notably calcitic and organic) and abiotic components of this material to elucidate how the planktonic signal is transported and ultimately preserved in sediments
Supervisors: Sluijs (UU-GEO), Middelburg (UU-GEO)
Host institute: UU-GEO
Required background/expertise:We are looking for a highly motivated PhD candidate who will generate a mechanistic understanding of the processes involved between production and burial of the most important proxy carriers. The candidate should have a background in Earth, environmental and/or marine sciences.
– Please click here to apply –

Title: Nitrogen fixation in the past
Project description: The marine nitrogen cycle, like the marine carbon cycle, is intrinsically linked to global climate dynamics. Despite this, and despite extensive study of the modern-day N-cycle, a thorough understanding of the paleo-N cycle remains elusive. For the reconstruction of the past oceanic N-cycle, the PhD candidate will utilize organic biomarkers, particularly those associated with nitrogen fixating cyanobacteria, including symbiotic species. Furthermore, techniques for compound specific δ15N will be developed and employed to evaluate the isotopic signature of N fixation.
Supervisors: Schouten (NIOZ), Bale
Host institute: NIOZ
Required background/expertise: Geochemistry, stable isotopes, earth sciences, analytical chemistry
– Please click here to apply –

Title: Reconstructing ancient seawater isotopes using hydrogen isotopic composition of organic biomarkers
Project description: The stable oxygen isotopic composition of foraminifera has been paramount in defining climate events over the Cenozoic, but unfortunately their 18O content does not only reflect changes in temperature but also in the 18O content of sea water. We will use an alternative method of constraining the evolution of the 18Osea water by analysing the d2H of organic biomarkers derived from photoautotrophs. Since 2H and 18O are directly coupled in sea water and the d2H of organic biomarkers is not affected by temperature nor, in case of isoprenoid compounds, by salinity, this proxy may allow an independent view of the isotopic changes of sea water over the Cenozoic. So far most of the biomarker d2H analyses in the marine realm have been done on haptophyte derived alkenones to reconstruct paleo sea surface salinity. This project aims to extend the method to other organic compounds including isoprenoids such as phytane, and combine this with bulk and/or foraminifera based d18O analyses to better understand seawater isotopes, d18O based temperature reconstructions, timing of glaciations and ice volume and salinity variability in the past.
Supervisors: Schouten (NIOZ), van der Meer
Host institute: NIOZ
Required background/expertise: Geochemistry, stable isotopes, earth sciences
– Please click here to apply –

Research theme: Tipping points and early warning - Two available positions coming up


Small and gradual changes in forcing can cause abrupt changes. This theme aims to identify, predict and understand tipping points

Title: Coupling of Tipping Elements in Networks of the Earth System
Project description: Large integrated climate models with a full coupling of ocean and atmospheric circulation mechanisms and ecosystem dynamics are notoriously difficult to formulate and parametrize. The PhD student will develop simplified network models, in order to get a deep understanding of potential dynamics resulting from the coupling of tipping elements, such as cascades, oscillations, and chaotic behavior. The PhD student will build and analyze both simple and complex models, and link the observed dynamics to modern and paleo climate data.
Supervisors: Scheffer (WUR), Dijkstra (UU-SCIENCE)
Host institute: WUR
Requirements: Demonstrated skills in building and analyzing models of dynamical systems and analyzing complex data sets. Basic knowledge of the functioning of the Earth system is an asset.
– Please click here to apply –

Title: Firn saturation as a tipping point for ice sheet melt
Project description: Firn, an up to 150 m thick layer of compressed snow, covers ~90% and >99% of the Greenland (GrIS) and Antarctic ice (AIS) sheets, respectively. It has been estimated that in the air pockets of the firn layer, ~45% (GrIS) and >99% (AIS) of the surface meltwater is retained and refrozen. This means that firn acts as an efficient buffer to ice sheet mass loss. However, when in a future warmer climate the melt rate increases, it is expected that at some point (a so-called tipping point), the firn layer can no longer sufficiently regenerate these air pockets in winter and becomes saturated, irreversibly losing its buffering capacity, leading to enhanced meltwater runoff, ice sheet mass loss and sea level rise. In this project we use regional climate models and firn models in combination with the latest output of global climate models from CMIP6, dynamically and statistically downscaled to high resolution over the ice sheets, to assess the current and future meltwater buffer capacity of the firn layers of the GrIS and AIS. The goal is to find melting thresholds beyond which the firn layer becomes saturated, leading to accelerated mass loss.
Supervisors: van den Broeke (UU-SCIENCE)
Host institute: UU-SCIENCE
Required background/expertise: Master’s degree in (geo)physics, meteorology, hydrology or comparable. Experienced in and/or affinity with programming and numerical model development.
– Please click here to apply –

None of the available projects have any potential ethical aspects associated with them. The obligatory secondments (internships) for each project, that can take place either in- or outside the Netherlands, could involve visits outside the EU, so called third countries. The project leaders will ensure that those research activities do not raise any ethical concerns and that the ethical standard and guidelines of Horizon2020 will be applied, regardless of the country in which the research is carried out. Possible research activities in third countries are low-risk. NESSC research does not involve any activities that are forbidden in any of the EU countries, nor does it make use of local resources, such as plant or animal materials, genetic materials, materials of historical value or traditional knowledge. Research in third countries will not put any of the researchers involved at risk. Supervisors will ensure that proper insurances are in place for travel by any project member.


NESSC is a so-called Gravitation Program, funded by the Dutch Ministry of Education, Culture and Science (OCW). The programme has recieved further funding from the Europen Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie, grant agreement No 847504.