ISOBASE

PROJECT SUMMARY:

The general objective of the project is to recognize the patterns of variability of the stable isotope (δ¹³C and δ¹⁵N) baselines for protein fraction in terrestrial temperate ecosystems: in plants and mammalian herbivores. In particular, the project main focus is checking if more-than-one isotopic baselines may occur within a community (of plants, or of mammalian herbivores) in an ecosystem. Our preliminary data suggests that this may be the case. If this hypothesis will be confirmed, it would mean that several independent baselines should be included in the isotope flux models, even for a single ecosystem.

The geological actualism approach in this project is to check: which exactly modern subcommunities of forest plants and herbivores have distinctly different baselines (subcommunities that differ in phylogeny, habitat, physiology?), if any; and whether such situation of multiple variable baselines is common in micro-ecosystems (e.g., dense canopy vs. open environment, conifer vs. deciduous forest?). The ultimate goal is to use these patterns of the modern isotopic variability in plants, herbivores, and plants-to-herbivores system, to better interpret the isotope flux in fossil assemblages, with the focus on bone collagen – usually the only organic material preserved in fossils. We focus on terrestrial temperate ecosystems, because such ecosystems are common in European Quaternary record (especially forest and mammoth steppe) and are among the majority of paleoecosystems studied in Europe, North America, Siberia, Beringia, and Patagonia. We focus on modern and fossil ecosystems from Poland: modern temperate forest (the Białowieża Forest), Early-to-Late Holocene forest paleontological assemblages (Perspektywiczna Cave, Shelter in Smoleń III); and mid-Vistulian mammoth steppe assemblage (Perspektywiczna Cave). A Late Glacial tundra assemblage (Perspektywiczna Cave) will be added for comparison.

The project methods are analyses of carbon and nitrogen stable isotopes in plants (protein, cellulose, lignin) and herbivores (bone collagen) material. Modern material (Białowieża Forest) will be used to refine the methodology: establishing the variability in plants and in herbivores; understanding the plant-to-collagen isotope fractionation; and to depict the complexity of the carbon and nitrogen isotopic flux within a plant-to-herbivore trophic network, where the Białowieża Forest is an actualistic model. Fossil material (from cave sites located in Polish Jura) of the Holocene forest ecosystem will be used to compare the fossil isotopic baselines with the modern ones and to test for the universality of the baseline variability among temperate forest ecosystems. Pleistocene assemblages (Perspektywiczna Cave) will be used to check the variability of the isotopic baselines in other ecosystems (mammoth steppe and tundra). We will further use the C-N flux model obtained for the modern ecosystem to better interpret the trophic relationships in fossil assemblages.

Among novel approaches is the individual amino acid isotopic analysis for terrestrial paleoecosystems. Until now, only few studies have undertaken this topic, mostly from the archaeological perspective. Other novel approaches include: searching for seasonal isotopic changes in plants; investigation of the local Suess effect through tree rings study; systematic analysis of the isotopic variation between ungulates, rodents and lagomorphs; assumption of several isotopic baselines within one ecosystem.

Isotopic baselines are necessary for stable isotope-based paleodietary modeling. In particular, the knowledge of the baseline variability is crucial at the planning phase of studies – to assume how much baseline samples is needed and what taxonomic variability is enough to represent baselines. In Quaternary sciences, such studies are common in paleoecology, with special focus on ancient hominines, extinct mammals, and the evolution of synanthropism. All such studies will largely benefit from this project’s results. Modern mammal-focused isotopic ecology will benefit as well, as it utilizes the same modeling methods. We can see the high importance of our study for: paleontology, archaeology, anthropology, environmental science, plant physiology, herbivore physiology, biochemistry, and indirectly for paleogeography and paleoclimatology.

Project acronym: “Isobase”

Funding: National Science Centre (Poland), OPUS-29 Programme

Project title: “Variability of carbon and nitrogen isotopic baselines in Quaternary terrestrial ecosystems”

Summary:https://projekty.ncn.gov.pl/en/index.php?projekt_id=644096

Project leader: Dr hab. Maciej T. Krajcarz (e-mail: mkrajcarz@twarda.pan.pl)

Application deadline: 31.07.2026

Announcement of recruitment results: by 31.08.2026

Scholarship start date: 01.10.2026

Duration of employment in the NCN project: 48 months

Scholarship: The NCN scientific scholarship of PLN 5,000 brutto brutto per month for the first 2 years (until the mid-term evaluation); the NCN scientific scholarship of PLN 6,500 brutto brutto per month for the remaining 2 years (after the mid-term evaluation, subject to a positive result of the mid-term evaluation)

Location: Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Warsaw (Twarda 51/55, 00-818 Warsaw), Quaternary GeoEcology Research Group (https://www.ing.pan.pl/en/research-groups/quaternary-geoecology-research-gr
 

REQUIREMENTS / EXPECTATIONS:

• A Master’s degree in Earth and environmental sciences/chemistry/biology or related disciplines;
• Strong organisational skills and the ability to multitask, work independently, and work in a team;
• A strong interest in Quaternary paleoecology and biogeochemical analyses;
• Experience in laboratory work;
• The ability to think critically and analyse data independently;
• Fluency in spoken and written English;
• Additional advantages will include: experience in Quaternary ecology/paleoecology, experience in applying stable isotope analyses, and familiarity with the R programming environment.

RESPONSIBILITIES:

• Laboratory work: documentation, selection, and preparation of samples; extraction of analytical fractions (proteins, cellulose, lignin); derivatisation of fractions for GC analysis;
• Analysis and interpretation of data obtained within the project;
• Participation in the preparation of scientific articles;
• Preparation of conference abstracts and periodic reports, and participation in international conferences;
• Presenting results at international conferences (oral presentations and posters);
• Participation in the GeoPlanet Doctoral School (https://www.ing.pan.pl/en/education/geoplanet-doctoral-school);
• The place of work will be the IGS PAS Research Centre in Warsaw, but foreign trips related to training and conferences will be necessary (paid by the Institute).
   

WE OFFER:

• Work at a leading research centre in Poland in the field of Earth and environmental sciences, and doctoral studies at the GeoPlanet Doctoral School (https://www.ing.pan.pl/en/education/geoplanet-doctoral-school);
• The opportunity to obtain a PhD degree in Earth and environmental sciences under the supervision of Dr hab. Maciej T. Krajcarz;
• A monthly salary in the form of the NCN scientific scholarship for 48 months (PLN 5,000 brutto for the first 2 years / PLN 6,500 brutto for the remaining 2 years);
• Participation in a research team led by Dr hab. Maciej T. Krajcarz, as part of a project funded by the NCN (grant no. 2025/57/B/ST10/02969);
• Collaboration with experienced researchers;
• Access to high-class geochemical facilities;
• Gaining experience in biogeochemistry of light isotopes and in laboratory procedures and the operation of research equipment available at the Stable Isotope Lab;
• The opportunity to take part in training courses and international conferences.

Note: The Institute of Geological Sciences, Polish Academy of Sciences, does not cover the costs of relocation to Poland/Warsaw, accommodation, or living expenses. The candidate must be financially prepared to cover these costs.

PROCESS:

The conditions for awarding the scientific scholarship are set out in the Regulations for awarding NCN scientific scholarships in research projects funded by the National Science Centre: https://www.ncn.gov.pl/sites/default/files/pliki/uchwaly-rady/2024/uchwala25_2024-zal1_ang.pdf

Additional information:

Dr hab. Maciej T. Krajcarz (project leader): mkrajcarz@twarda.pan.pl.

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