Gutenberg Open Science
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Recent Submissions
The bivalve Glycymeris planicostalis as a high-resolution paleoclimate archive for the Rupelian (Early Oligocene) of central Europe
(2015) Walliser, Eric Otto; Schöne, Bernd Reinhard; Tütken, Thomas; Zirkel, Jessica; Grimm, Kirsten; Pross, Jörg
Current global warming is likely to result in a unipolar glaciated world with unpredictable repercussions on atmospheric and oceanic circulation patterns. These changes are expected to affect seasonal extremes and the year-to-year variability of seasonality. To better constrain the mode and tempo of the anticipated changes, climatologists require ultra-high-resolution proxy data of time intervals in the past, e.g., the Oligocene, during which boundary conditions were similar to those predicted for the near future. In the present paper, we assess whether such information can be obtained from shells of the long-lived bivalve mollusk Glycymeris planicostalis from the late Rupelian of the Mainz Basin, Germany. Our results indicate that the studied shells are pristinely preserved and provide an excellent archive for reconstructing changes of sea surface temperature on seasonal to interannual timescales. Shells of G. planicostalis grew uninterruptedly during winter and summer and therefore recorded the full seasonal temperature amplitude that prevailed in the Mainz Basin ~ 30 Ma. Absolute sea surface temperature data were reconstructed from δ18Oshell values assuming a δ18Owater signature that was extrapolated from coeval sirenian tooth enamel. Reconstructed values range between 12.3 and 22.0 °C and agree well with previous estimates based on planktonic foraminifera and shark teeth. However, temperatures during seasonal extremes vary greatly on interannual timescales. Mathematically re-sampled (i.e., corrected for uneven number of samples per annual increment) winter and summer temperatures averaged over 40 annual increments of three specimens equal 13.6 ± 0.8 and 17.3 ± 1.2 °C, respectively. Such high-resolution paleoclimate information can be highly relevant for numerical climate studies aiming to predict possible future climates in a unipolar glaciated or, ultimately, polar-ice-free world.
Hydrogen and oxygen isotopes in vertebrate tissues vary by diet type
(2025) Reynard, Linda M.; Leichliter, Jennifer N.; Winkler, Daniela E.; Clauss, Marcus; Tütken, Thomas
Hydrogen and oxygen isotope ratios in proteinaceous tissues have been used for some time in migratory, ecological, and archaeological studies. While the result of isotopic variation in drinking water and diet has been investigated with controlled feeding experiments and studies in the wild, there are few controlled feeding studies that manipulate the diet components and diet type, and this across different taxa. In this experiment, the diet fed to rats, guinea pigs, and quail varied from plant-based to insect-based and meat-based pelleted diets. We report the diet to tissue offsets for δ2H (denoted Δδ2H) and δ18O (Δδ18O) of tissue-bound organic matter in two tissue types: muscle and dentine collagen. The diet to tissue offset varies by diet type in muscle of all three species, by up to 16 ‰ (Δδ2H) and 2 ‰ (Δδ18O). In dentine collagen, a range of ~20 ‰ in Δδ2H and ~1.5 ‰ in Δδ18O are observed across diets, though in a smaller number of samples. Additionally, we note large variation in Δδ2H and Δδ18O by tissue type (δ2H = ~60 ‰, δ18O = ~3–4 ‰) and more moderate differences by species (up to δ2H = 7.4 ‰, δ18O = 1.5 ‰). The difference in consumer tissue Δδ2H and Δδ18O by diet type is important to consider as a source of isotopic variability for some studies such as migratory research or diet or drinking water reconstructions and (palaeo-)climate inferences drawn from them, particularly in species that may vary their dietary habits.
Oxygen and carbon isotope variations in a modern rodent community : implications for palaeoenvironmental reconstructions
(2012) Gehler, Alexander; Tütken, Thomas; Pack, Andreas
Background: The oxygen (d18O) and carbon (d13C) isotope compositions of bioapatite from skeletal remains of fossil
mammals are well-established proxies for the reconstruction of palaeoenvironmental and palaeoclimatic conditions. Stable
isotope studies of modern analogues are an important prerequisite for such reconstructions from fossil mammal remains.
While numerous studies have investigated modern large- and medium-sized mammals, comparable studies are rare for
small mammals. Due to their high abundance in terrestrial ecosystems, short life spans and small habitat size, small
mammals are good recorders of local environments.
Methodology/Findings: The d18O and d13C values of teeth and bones of seven sympatric modern rodent species collected
from owl pellets at a single locality were measured, and the inter-specific, intra-specific and intra-individual variations were
evaluated. Minimum sample sizes to obtain reproducible population d18O means within one standard deviation were
determined. These parameters are comparable to existing data from large mammals. Additionally, the fractionation
between coexisting carbonate (d18OCO3) and phosphate (d18OPO4) in rodent bioapatite was determined, and d18O values
were compared to existing calibration equations between the d18O of rodent bioapatite and local surface water (d18OLW).
Specific calibration equations between d18OPO4 and d18OLW may be applicable on a taxonomic level higher than the species.
However, a significant bias can occur when bone-based equations are applied to tooth-data and vice versa, which is due to
differences in skeletal tissue formation times. d13C values reflect the rodents’ diet and agree well with field observations of
their nutritional behaviour.
Conclusions/Significance: Rodents have a high potential for the reconstruction of palaeoenvironmental conditions by
means of bioapatite d18O and d13C analysis. No significant disadvantages compared to larger mammals were observed.
However, for refined palaeoenvironmental reconstructions a better understanding of stable isotope signatures in modern
analogous communities and potential biases due to seasonality effects, population dynamics and tissue formation rates is
necessary.