Drought-induced tree mortality is occurring more frequently in the world, with both the direct impact of drought (i.e., heat and drought events) and the mortality predisposition (e.g., tree nutrition status) influencing death or survival of trees. The oxygen and hydrogen isotopic compositions (δ¹⁸O and δ²H) of plant water are widely used as hydrological indicators. Both elements in water are tightly correlated and are the key source for the isotopic composition of plant organic matter. Yet, recent studies show that the relationship between δ¹⁸O and δ²H values in organic matter is weaker and more divergent. This is probably caused by physiological and metabolic processes (i.e., assimilation, assimilate allocation, use of reserves) that are integrated into δ²H but not into δ¹⁸O. This let us hypothesize that δ²H can function as a useful tool in tree mortality research to study assimilate and storage related reason (i.e., carbon starvation) of tree death, but more knowledge is urgently needed.

To test our hypothesis, we studied the pre-disposal fertilization and drought effects on δ¹⁸O and δ²H values in plant water and organic matter in a greenhouse experiment. We planted three years old saplings of Abies alba, Acer pseudoplatanus, Picea abies, Pinus sylvestris and Quercus petraea, half of which were treated with a slow-release formula fertilizer (control (F0) and fertilization (F+)); one year later, half of the F0 and half of the F+ plants were selected for a lethal drought treatment (control (D0) and drought (D+)), i.e., D0 plants were watered to field capacity, while D+ plants received no more water until they died. After 6 weeks of drought, leaf and twig samples were collected for δ¹⁸O and δ²H analyses of plant water. After the D+ plants died (i.e., 9-15 weeks after start of drought), additional leaf and stem material were collected from a same number of D0 and D+ plants. Organic matter of leaf and tree-ring of the recent year were prepared for δ¹⁸O and δ²H analyses. Additional physiological and metabolic factors were measured to examine the treatment effects.

Across all species, we found that the pre-disposal fertilization had no significant effect on δ¹⁸O and δ²H values of plant water and organic matter. On the other hand, the drought treatment significantly increased both δ¹⁸O and δ²H values of leaf and twig water, while it only significantly increased δ²H values of leaf and tree-ring organic matter. These results indicate that δ²H in leaf and tree-ring organic matter in dying trees can capture drought-induced tree mortality signals. We propose that the ²H-enrichment in the drought-exposed trees might be related to (i) the imprint of ²H-enriched signal of plant water; (ii) drought-induced changes in the metabolic processes of sugar biosynthesis; (iii) drought-induced changes in the use of carbon reserves. In summary, our study supports the idea that hydrogen isotopes can function as a potential diagnostic tool in tree mortality studies.

How to cite: Diao, H., Lehmann, M. M., Ouyang, S., and Gessler, A.: Hydrogen isotopes in leaf and tree-ring organic matter as potential indicators of drought-induced tree mortality, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5629, https://doi.org/10.5194/egusphere-egu23-5629, 2023.

Stable isotope compositions of carbon (δ¹³C) and oxygen (δ¹⁸O) in plant carbohydrates such as photosynthetic assimilates or cellulose are widely applied tools to reconstruct climate and plant physiological responses. In contrast, applications of hydrogen isotope composition (δ²H) in plant carbohydrates are limited because of previous methodological constrains and limited knowledge on processes causing hydrogen isotope fractionations. To better understand the individual climatic drivers of isotopic variations in tree rings, particularly for δ²H, we performed a controlled experiment over one growing season in climate chambers with saplings of broadleaf and conifer tree species. The growing conditions resembled conditions that can be typically found in the field: vapor pressure deficit (VPD; 1.0, 1.6, and 2.2 kPa), air temperature (T; 25 and 30 °C), and soil drought (D, well-watered and extreme dry).  After 5 months of treatment, δ¹³C, δ¹⁸O, and δ²H of water, sugars and starch in stems and leaves, as well as in cellulose of the recent year tree rings were measured. For δ²H analyses of plant carbohydrates, we applied a newly developed hot water vapour equilibration method (Schuler et al., 2022, doi.org/10.1111/pce.14193). Across all species, first results show that the three elements in tree-ring cellulose respond differently to the climatic drivers: both δ²H and δ¹³C values increased with increases in D and VPD, but the VPD responses were more pronounced under high than under low T conditions. In contrast, δ¹⁸O values were affected by T and VPD, while the VPD response was more pronounced under wet than under dry soil D conditions. Thus, the combination of δ²H and δ¹³C values could be used to identify D occurrences independent of VPD conditions, while δ¹⁸O value is a better indicator for T and VPD responses. In the following steps, the isotopic variations in tree-ring cellulose will be linked to those in water, sugars, and starch and their concentrations in leaf and stem material, as well as to various other structural and functional traits which have been measured throughout the experiment (Schönbeck et al., 2022, doi.org/10.1111/pce.14425). With this unique experimental design, we aim to provide new knowledge facilitating the interpretation of stable isotope patterns in tree rings under field conditions.

How to cite: Lehmann, M. M., Schuler, P., Schönbeck, L., Rehmann, O., Diao, H., Vitali, V., and Grossiord, C.: Effects of vapour pressure deficit, temperature and soil drought on triple isotope patterns of assimilates and tree-ring cellulose, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6353, https://doi.org/10.5194/egusphere-egu23-6353, 2023.

It is essential to comprehensively understand past climate and tree response to climate change because trees are directly exposed to rapid, intensifying, and widespread climate change. Both tree rings and leaf n-alkanes are long-term biomarkers which can help to better understand past climate and/or tree response to climate change. For example, interpreting carbon and oxygen stable isotopes in tree rings contribute to understanding past climate and tree response to climate change. However, greater insight could be achieved if hydrogen stable isotopes can also be clearly interpreted. To clearly interpret hydrogen isotopes in tree rings it is necessary to discover which aspects of climatic variability and tree physiology are most clearly expressed by hydrogen isotopes in tree rings. Additionally, the climatic signal of hydrogen stable isotopes in leaf n-alkanes can be deposited to soil and sediments from plants, and their climatic soil record can date back to thousands to millions of years ago. However, there are still aspects of plant physiology that have not been accounted for in leaf n-alkane hydrogen isotope interpretation, which limits the reliability of their interpretation. While data from tree rings and leaf n-alkanes are rarely combined, both tree rings and leaf n-alkanes contain a hydrogen isotope signal that originates from a hydrogen isotope signal in source water that is changed by physiological processes and interacting climatic factors during their biosynthesis. This project aims to improve our understanding of the physiological and climatic signals contained in the hydrogen isotope signal in both tree rings and leaf n-alkanes. It helps increase the useability of the hydrogen isotope signal in tree rings and helps improve the reliability of interpreting climatic signals from leaf n-alkanes. It uses a unique dataset from a field survey with samples collected multiple times during a growing season, with high temporal resolution, at one to two boreal forests in southern Finland (e.g., Leppä et al. 2022; Tang et al., 2022). This dataset is rich with information from multiple sources, such as multiple element isotope concentrations in various plant tissues and water isotope pools, as well as leaf gas exchange data, meteorological data, and eddy covariance data. The hydrogen isotope signal is traced from the climatic signal in source water, to the physiological and climatic signal in leaf water, sugars and starches and leaf n-alkanes, then from the same leaf water, sugars, and starches to bark and stem phloem sugars and starches, to high-resolution intra-annual tree ring α-cellulose. This presentation gives the project outline and some main findings.

Leppä et al. (2022) doi:10.1111/nph.18227

Tang et al. (2022) doi: 10.1093/treephys/tpac079

How to cite: Angove, C., Lehmann, M., Saurer, M., Wiesenberg, G., Young, G., and Rinne-Garmston, K.: Unlocking the physiological and climatic hydrogen isotope signal in tree rings and leaf n-alkanes in a boreal forest, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14059, https://doi.org/10.5194/egusphere-egu23-14059, 2023.

Appreciation for the influence of plant metabolism on the hydrogen isotope composition (δ²H) of plant compounds has increased in recent years, adding new opportunities to understand how plants respond to environmental change. In general, where carbon supply is limited (e.g. at the beginning of the growth season, in darkness, under low CO₂), the resulting δ²H of newly produced plant compounds tends to be ²H-enriched. The source of the ²H-enrichment has yet to be identified but hypotheses include: 1) a direct effect of reduced photosynthesis; 2) change in the partitioning of photoassimilates to sucrose/transitory starch; 3) use of longer-term starch reserves; and/or, 4) increased isotopic exchange with water suggesting increased metabolite cycling. To test these ideas, we utilised samples collected from a study which grew tree saplings under 100% and 6% of ambient sunlight in the field (Weber et al. 2018, New Phytologist, 222: 171-182).  In general, relative growth rate was attenuated by a species-specific amount that ensured homeostasis of non-structural carbohydrate (NSC) concentrations; however, not before an initial two-fold reduction in NSC levels – the time period the current study focussed on. Cellulose was purified and n-alkanes extracted from leaves of six deciduous species (Betula pendula, Carpinus betulus, Fagus sylvatica, Prunus avium, Quercus petraea and Tilia platyphyllos) in July 2016, around one year after the shade treatment began. The isotopic difference of cellulose between shaded and full sunlit grown leaves (ε_shade-sun) was significantly different from zero, with species-specific offsets ranging between 20 to 70‰. In comparison, the treatment effect was minimal for the C-chain length concentration weighted δ²H values of n-alkanes, ranging between -7 to +10‰. To narrow down the source of ²H-enrichment in leaf cellulose, the δ²H of sucrose and starch are currently being analysed in samples collected from stem wood (without bark) before bud-break in March 2016, and in leaf and stem material sampled after leaf-out in July 2016. An increase in sucrose δ²H values from shade leaves relative to controls would support Hypothesis 1 and 2; ²H-enriched storage starch relative to leaf sucrose would support Hypothesis 3; and an increase in the δ²H of sucrose in stem wood relative to storage starch (before bud-break), would support Hypothesis 4. Our study has important implications for interpreting ²H-enrichment of plant compounds with respect to reduced C supply.

How to cite: Holloway-Phillips, M., Wacker, A., Hoch, G., Nelson, D. B., Lehmann, M., and Kahmen, A.: Identifying sources of hydrogen isotope fractionation in plant carbohydrates and lipids under low carbohydrate supply, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9401, https://doi.org/10.5194/egusphere-egu23-9401, 2023.

The analysis of the isotopic composition in herbarium specimens gives insight into the physiological responses of plants to environmental change. Specifically, the carbon isotope composition of plants is linked to the time-integrated, leaf-level intrinsic water use efficiency (i.e., the ratio of net photosynthesis over stomatal conductance), while the oxygen isotope composition is linked to leaf stomatal conductance. Thus, by combining stable isotope analyses of carbon and oxygen, trends in integrated values for net photosynthesis and stomatal conductance can be determined. Here, we present results from analyses of carbon and oxygen isotope values from over 3000 sampled herbarium specimens, that have been collected across Switzerland over the past century covering more than 80 herbaceous plant species and a wide range of habitats. While plants across most taxa and habitats have increased their intrinsic water use efficiency over the last decades, the contribution of net photosynthesis or stomatal conductance to changes in intrinsic water use efficiency differs among different plant functional groups (herbs, legumes, grasses, and sedges). Applying a multi-model approach, our study demonstrates that the carbon and water relations of plants respond to long-term changes in the environment but that the physiological nature of these responses differs among plant functional groups and the plant’s ecological niche.

How to cite: Basler, D., Nelson, D. B., de Vos, J., Moreno-Gutiérrez, C., and Kahmen, A.: Long-term physiological responses of herbaceous plants to global change from carbon and oxygen isotopes in herbarium specimen, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12998, https://doi.org/10.5194/egusphere-egu23-12998, 2023.

Stable hydrogen isotope may provide evidence to identify the botanical origin of exogenous sugars added to honey, due to a combination of factors such as the systematic global variation of meteorological waters and morphological differences affecting rates of evapotranspiration prior to water incorporation into plant carbohydrate prior to photosynthesis. Here we report an simplified method, which involves the preparation of hexamethylenetetramine (HMT), produced through chemical transformation of sugar molecules, to allow direct analysis of the carbon-bound non-exchangeable hydrogen (CBNE) by elemental analyser high temperature chromium reduction coupled to Isotope Ratio Mass Spectrometry (EA-Cr/HTC-IRMS). We have optimized the reaction conditions for oxidation and derivatisation in terms of reaction time and pH of solution. A two month-monitoring for of the repeatability of δ²H values of an HMT standard  has demonstrated stable and reliable results of this technique. The procedure is relatively straightforward, convenient and easy to apply compared with alternative reported CBNE analysis methods for foodstuffs, particularly those where isolating sugars is challenging and consensus over dual-water equilibration conditions are contentious.  Moreover, it has the advantage over other methods by avoiding the use of corrosive and explosive reagents such as sugar nitro-derivatives.  This study has also demonstrated the potential to identify from the presence of rice syrup, which is currently a significant challenge for the honey industry.

How to cite: Li, A., Abrahim, A., and Kelly, S.: Stable Isotope Analysis of Non-exchangeable Hydrogen in Sugars by Oxidation/Derivatisation to hexamethylenetetramine and Elemental Analyzer-Chromium/High Temperature Conversion- Isotope Ratio Mass Spectrometry, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16499, https://doi.org/10.5194/egusphere-egu23-16499, 2023.

Polysaccharides, e.g. starch, are the most abundant biopolymers on earth. They are long chain monosaccharides linked by glycosidic bonds and are playing different important roles in plants such as energy storage (e.g. starch and glycogen) structure and growth (e.g. cellulose and pectin).The determination of carbon bound non-exchangeable (CBNE) hydrogen isotope ratios in polysaccharides are of great interest in a broad range of research areas, as they contain intrinsic information about the metabolic pathway and geographical origin of the plant, derived from water incorporated during photosynthesis. Measuring non-exchangeable hydrogen isotope ratios in starch is challenging using methods such as the dual water-equilibration technique, which are labour intensive and open to a certain degree of contention of over equilibration times, temperatures, proportions of exchangeable hydrogen and fractionation factors. We report on a new approach, to determine non-exchangeable hydrogen isotopes in starch, after hydrolysis of the biopolymer into monosaccharides followed by conversion into volatile trifluoroacetamide (TFA) derivatives and analysis by GC-CrAg/HTC-IRMS.

This new methodology (Figure.01) is rapid and simple compared to current available methods and should allow CBNE hydrogen isotope analysis to be more easily and widely used.

How to cite: Abrahim, A. and Kelly, S.: Determination of carbon bound non-exchangeable (CBNE) hydrogen isotope ratios in starch by Microwave Assisted Hydrolysis (MAH) and GC-CrAg/HTC-IRMS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16747, https://doi.org/10.5194/egusphere-egu23-16747, 2023.

As plant organic compounds are formed, their hydrogen isotopic composition (δ²H) is influenced by the hydrology of the environment as well as by the plant metabolism, and hence contains information about both. Until recently, cellulose has been the only plant carbohydrate routinely measured, because it persists in tissues over long time scales and can therefore be used to understand time-integrated signals preserved in tissues like tree rings. However, knowledge gaps about how environmental and metabolic signals are imprinted in the cellulose δ²H value currently limit the interpretation of cellulose δ²H variation with respect to plant metabolism. Measuring δ²H values of biosynthetic intermediates like sugar molecules from fresh tissue offers a possibility of filling some of these knowledge gaps to better understand the cellulose δ²H signal.

Measuring δ²H values in carbohydrates is complicated by the presence of hydroxyl hydrogen. This is because this hydrogen pool can isotopically exchange with surrounding liquid water or water vapor (e.g., during sample processing and analysis), obscuring the primary plant hydrological and metabolic information contained in the isotopic values of carbon-bound hydrogen. The contribution of exchangeable hydrogen can be accounted for using dual equilibration techniques, but in most cases, these permit only analyses of bulk leaf extracted sugars. Thus, another difficulty lies in obtaining individual sugar compounds from plants. An alternative to dual equilibration is therefore to derivatize the plant sugars prior to analysis with hydrogen of known isotopic composition to form new compounds that no longer contain exchangeable hydrogen, e.g., by acetylation. Acetylation makes sugar compounds amenable to gas chromatography (GC), so this technique also allows for compound-specific analyses of multiple compounds in the same sample, such as different sugar types. GC analysis also has the advantages of requiring smaller sample amounts and providing better assurances of sample purity than are possible for bulk sample measurement approaches.

Here, we present results on streamlining our acetylation approach to facilitate rapid and cost-effective purification from sample matrices of water-soluble plant carbohydrate extracts. We acetylate whole carbohydrate extracts, and then compare recovering sugar acetates from the sample matrix by liquid-liquid separation with recovery by reverse-phase solid phase extraction (SPE) using a C18 sorbent. The liquid-liquid separation yields a higher recovery than SPE but is much more labor-intensive, whereas the SPE method can be scaled easily for higher sample throughput. Both methods proved successful for purifying water-soluble sugar samples as well as digested starch (glucose) from plant leaf, wood, and root material, yielding GC amenable sugar acetates that are soluble in acetone. Sucrose octaacetate is well resolved under normal GC measurement conditions on commonly available GC columns (e.g., DB-5), without requiring instrument modification as is the case for halogenated sample compounds.

How to cite: Hugger, S., Holloway-Phillips, M., Kahmen, A., and Nelson, D. B.: A new solid phase extraction method for purifying plant sugars for compound-specific hydrogen isotope analysis, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14146, https://doi.org/10.5194/egusphere-egu23-14146, 2023.

Since micro-organisms were first visualised by Robert Hooke and Antoni van Leeuwenhoek, bacteria and protists were quickly categorised as either primary producers or consumers and thus forming the base of the marine food web. New conceptual understanding sees this traditional dichotomy between autotrophs and heterotrophs in the marine food web replaced by one that recognises that mixotrophy is widespread. Many "phytoplankton" eat, while 50% of "microzooplankton" perform photosynthesis. This mixotrophic behaviour affects the cycling of nutrients, enhances primary production, biomass transfer to higher trophic levels, and the marine sequestration of atmospheric CO₂. Moreover, the mixotrophic behaviour of many toxic protists could also be partly responsible for their ecological success and the occurrence of Harmful Agal Blooms (HABs).

While science requires a tool to measure the contributions of phototrophy and heterotrophy in plankton to help in biogeochemical modelling, my colleagues and I have already shown that hydrogen (H) isotopic signature (i.e. d²H) of lipids is uniquely sensitive to the expression of heterotrophy relative to photosynthesis in terrestrial plants and bacteria. This presentation will discuss groundwork experiments performed with Chlorella sorokiniana, Prymnesium parvum and Emiliania huxleyi that had for objective to explore whether d²H values of diverse compounds produced by protists are similarly sensitive to their central metabolic pathway. Hydrogen isotope analyses performed on organic compounds from these experiments, using an isotope ratio mass spectrometer (IRMS) coupled to a gas chromatograph (GC), suggest that H isotopic signature of lipids is indeed sensitive to the level of heterotrophic growth in diverse protists.

If this relation can be confirmed and calibrated, compound specific hydrogen isotope analyses could provide a powerful means to study the role of mixotrophy on the global carbon cycle, the cycling of nutrients and the occurrences of HABs.

How to cite: Cormier, M.-A., Berard, J.-B., Flynn, K., Bougaran, G., and Rickaby, R.: Investigating the "mixoplankton" paradigm using hydrogen isotope ratios, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16142, https://doi.org/10.5194/egusphere-egu23-16142, 2023.

Metabolic water, the water that is produced from O₂ during respiration, carries an isotopic signature that can be different from that of the water the cell is growing in. It has been well known that for large land organisms, like birds and mammals, metabolic water contributes significantly to the water balance and has an important control on the signature of the oxygen-stable-isotopes of the water inside the organism. This isotopic signature is then carried over through isotopic equilibrium to other oxygen-bearing species like phosphate. However, for small organisms like bacteria, it has been widely assumed for decades, that the large surface area to volume ratio enables a fast exchange of the cell water with the ambient water. As a result, the isotopic signature of the metabolic water will be heavily diluted and erased. In contrast, a recent work reported indirect evidence of significant control of metabolic water on the oxygen isotopes inside microbial cells. This indirect evidence is based on deviations of oxygen isotopes in phosphate from the expected equilibrium with the ambient water. Here we report the results of experiments that directly tested the possible contribution of metabolic water to phosphate oxygen isotopes in bacteria. We found that ambient water did control the oxygen isotopes in the phosphate. However, there were large deviations from the expected equilibrium. Nevertheless, we found that these deviations were not correlated with the isotopic composition of metabolic water. Hence, other mechanisms, which will be discussed, are responsible for these deviations.

How to cite: Angert, A., Weiner, T., Tamburini, F., Zer, H., and Keren, N.: Does metabolic water control the isotopic composition of water in microbial cells?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2218, https://doi.org/10.5194/egusphere-egu23-2218, 2023.

Dissolved organic matter (DOM) cycling is essential to understanding energy flow in aquatic ecosystems and their role as a source or sink of CO₂ in the global carbon cycle. Quantifying DOM turnover and reactivity have been confounded by the barely detectable changes in the molecular composition and ¹³C & ¹⁵N stable-isotope compositions. We hypothesized that significant seasonal isotopic changes in environmental waters and primary biological productivity might be reflected in the H & O stable-isotope composition of DOM, providing an alternative way to assess the accumulation, turnover, and transport of DOM in aquatic environments. H & O stable-isotope analyses of DOM from lakes showed temporal coupling of water isotopes with organic molecules that accumulate in natural aquatic environments, which varied between catchments and by molecular size components of DOM. An in-situ stable-isotope labelling (HDO) experiment revealed (microbial) turnover of DOM occurred on a weekly timescale. Further development of δ²H- and δ¹⁸O-DOM analyses may improve our understanding of the provenance and processing of DOM and help better constrain unknowns in the metabolic balance of inland waters.

How to cite: Meador, T. B., Jabinski, S., Mičanová, A., Zehetner, N., Umbria-Salinas, K., Pilecky, M., and Wassenaar, L.: DOH! – The interface of isotope hydrology, ecology, and organic geochemistry, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17216, https://doi.org/10.5194/egusphere-egu23-17216, 2023.

The ¹⁸O/¹⁶O ratio of a-cellulose in land plants has proved of interest for climate, environmental, physiological and metabolic studies. Reliable application of such ratio may be compromised by the presence of hemicellulose impurities in the a-cellulose product obtainable with current extraction methods, as the impurities are known to be isotopically different from that of the a-cellulose. We firstly compared the quality of hydrolysates of “a-cellulose products” obtained with four repre-sentative extraction methods (JAYME and WISE; BRENDEL; ZHOU; LOADER) and quantified the hemicellulose-derived non-glucose sugars in the “a-cellulose products” from 40 land grass species using GC/MS. Secondly, we performed com-pound-specific oxygen isotope analysis for the hydrolysates using GC/Pyrolysis/IRMS. These results were then compared with the bulk isotope analysis using EA/Pyrolysis/IRMS of the “a-cellulose products”. We found that the ZHOU method afforded overall the highest purity a-cellulose as judged by the minimal presence of lignin, and the second lowest presence of non-glucose sugars in the investigated grass species. Isotopic analysis then showed that the O-2~O-6 of the a-cellulose glucosyl units were all depleted in ¹⁸O by 0.0-4.3 mUr (with an average of 1.9 mUr) in a species-dependent manner relative to the a-cellulose products. The positive isotopic bias of using a-cellulose product instead of the glucosyl units stems mainly from the fact that the pentoses that dominate hemicellulose contamination in the a-cellulose product are relatively enriched in ¹⁸O (compared to hexoses) as they inherit only the relatively 18O-enriched O-2~O-5 moiety of sucrose, the common bio-chemical precursor of pentoses and hexoses in cellulose, and are further enriched in ¹⁸O by the (incomplete) hydrolysis. Failure to prepare a-cellulose with the highest possible purity, free from lignin and hemicellulose contamination, can bias predictions based on mechanistic models linking a-cellulose oxygen isotope composition to plant growth conditions.

How to cite: Zhou, Y.: On the chemical purity and oxygen isotopic composition of a-cellulose extractable from higher plants and the implications for climate, metabolic and physiological studies, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3902, https://doi.org/10.5194/egusphere-egu23-3902, 2023.