Nanako O. Ogawa

Detection of endogenous biomolecules in vertebrate fossils remains controversial because labile compounds degrade quickly and are highly susceptible to contamination. Here, we present data on the preservation of heme-derived tetrapyrroles, and vascular canal-constrained ellipsoidal microstructures, inferred to be red blood cells, in limb bones of Aratasaurus museunacionali , a 115-million-year-old theropod dinosaur. High-performance liquid chromatography–mass spectrometry identified parent and diagenetically altered heme B as the principal tetrapyrroles of bone extract, contrasting the chlorophyll and bacteriochlorophyll porphyrin signatures of the surrounding matrix supporting an endogenous origin. Separate spatially resolved analyses by Raman spectroscopy and transmission electron microscopy confirmed the ellipsoid microstructure localization of i) porphyrin signals of heme and ii) key elements of heme (Fe, N, and C) and mineral stabilizing hausmannite (Mn ₃ O ₄ ), respectively. These results demonstrate blood-derived biomolecules in mineralized red blood cells of a dinosaur.

Polycyclic aromatic hydrocarbons (PAHs) are widely used to distinguish pyrogenic from petrogenic organic matter in modern and ancient sedimentary archives. However, their applicability in charcoal-rich coal-measure successions remains poorly constrained, particularly where solid combustion residues dominate the preserved PAH inventory. Here, we investigate PAH distributions in a well-dated Norian (~222–217 Ma), high-latitude (~66°S) fluvio-lacustrine succession of the Mount Nicholas Coal Measures (BIC 3A core, eastern Tasmania, Australia) containing abundant macroscopic charcoal. We combine sedimentary and charcoal-bound PAHs with scanning electron microscopy of charcoal, bulk organic carbon isotopes, and independent fire- and fuel-related molecular indicators to evaluate commonly applied diagnostic PAH ratios in a char-dominated coal-bearing system.Sedimentary and charcoal-derived PAHs occupy conventionally defined pyrogenic, mixed-source, and petrogenic fields on widely used diagnostic cross-plots and in the Alkylated Phenanthrene Derivative Index. Charcoal-derived PAHs reproduce the distributions observed in the sedimentary assemblage and closely resemble experimentally produced gymnosperm char residues. Ratios based on low- and high-molecular-weight PAHs indicate a predominance of char/burn residues over smoke-derived inputs, while charcoal anatomy, retene, cadalene, and dimethylphenanthrene isomer distributions independently support combustion of gymnosperm vegetation. These results show that physically identified charcoal can yield mixed-source and nominally petrogenic classifications, demonstrating that PAH source ratios are non-unique in charcoal-rich coal measures. PAH ratios should therefore be interpreted alongside independent evidence for combustion phase, fuel type, and depositional context when reconstructing wildfire and organic-matter sources in coal-bearing sedimentary archives.

The CI (Ivuna-type) carbonaceous material returned from asteroids Ryugu and Bennu contain mobilized sodium from the evaporation or freezing of liquid water into brines, shedding light on the internal structure of ice-rich CI-type worlds and the formation of prebiotic organic compounds. The formation of brines has not been demonstrated in CM (Mighei-type) carbonaceous chondrites, which also supplied organic matter to the early Earth. Here, we announce the fall of a primitive meteorite from a daytime fireball over the New York metropolitan area in July 2024. It is a CM2 breccia that contains unique CM1 clasts rich in water and sodium. The meteorite contains abundant amino acids and other products of organic chemistry in brines that reveal subsurface processes on CM-type asteroid parent bodies.

Climate-driven increases in primary production are expected to alter the organic matter reaching the Arctic seafloor. While polar organisms can respond rapidly to changes in food pulses, there is limited information on how different benthic compartments exhibit distinct physiological and population-level responses. Here, we evaluated the responses of benthic foraminifera to the addition of ¹³ C-labelled algae powder under ambient conditions and a warmer temperature setting. We quantified the species-specific ingestion rates of selected foraminifera taxa from shelf and slope regions characterised by distinct water depths and hydrographic conditions. Our results demonstrated that shelf foraminiferal assemblages had higher uptake than slope assemblages, despite the latter having generally higher abundance. Both suspension feeders and detritivores (e.g. Saccorhiza ramosa and Cribrostomoides subglobosus , respectively) had high feeding rates, indicating that species-specific uptake is related to feeding preferences and strategies. Most taxa did not exhibit increased feeding under warm conditions, except for C. subglobosus and certain calcareous taxa, suggesting that warming effects are secondary and species-specific. Background foraminiferal isotopic signatures (d ¹³ C, d ¹⁵ N) evidenced trophic plasticity in Arctic benthic foraminifera, as Lagenammina difflugiformis , Elphidium clavatum and Melonis affinis showed varying isotopic values across sites. Our findings indicate that future warming may alter benthic carbon cycling not through generalised metabolic acceleration due to higher water temperature, but through species-specific shifts that should restructure community biodiversity and trophic roles.

The CI (Ivuna-type) carbonaceous material returned from asteroids Ryugu and Bennu contain mobilized sodium from the evaporation or freezing of liquid water into brines, shedding light on the internal structure of ice-rich CI-type worlds and the formation of prebiotic organic compounds. The formation of brines has not been demonstrated in CM (Mighei-type) carbonaceous chondrites, which also supplied organic matter to the early Earth. Here, we announce the fall of a primitive meteorite from a daytime fireball over the New York metropolitan area in July 2024. It is a CM2 breccia that contains unique CM1 clasts rich in water and sodium. The meteorite contains abundant amino acids and other products of organic chemistry in brines that reveal subsurface processes on CM-type asteroid parent bodies.

Organic molecules delivered from extraterrestrial materials may have played a key role in supplying building blocks for life on Earth. Here we report all five canonical nucleobases—purines (adenine and guanine) and pyrimidines (cytosine, thymine and uracil)—in samples returned from the C-type asteroid (162173) Ryugu by JAXA’s Hayabusa2 mission and compare the results with data from similar extraterrestrial material. Ryugu samples contain nearly equal amounts of purines and pyrimidines, whereas Murchison is enriched in purines and Bennu and Orgueil in pyrimidines. Samples from Ryugu, Bennu and Orgueil, which have a similar mineralogy and elemental composition, show purine-to-pyrimidine ratios negatively correlating with ammonia. These observations indicate that the nucleobases in these samples may have formed via a shared pathway depending on the physicochemical environment of the respective parent bodies. The detection of diverse nucleobases in asteroid and meteorite materials demonstrates their widespread presence throughout the Solar System and reinforces the hypothesis that carbonaceous asteroids contributed to the prebiotic chemical inventory of early Earth.

Salt marshes, which sustain high productivity, serve as essential living environments for a wide range of organisms. The aquatic food web in salt marshes is basically supported by the high primary production of aquatic algae within the intertidal zone and the organic matter contributed from the terrestrial ecosystems, including the adjacent supratidal zone. As salt marshes facilitate the incorporation of terrestrially fixed energy into estuarine and marine food webs, they represent a key environment for understanding energy transfer from land to marine ecosystems. However, the energy contribution from terrestrial ecosystems to salt marsh food webs remains unquantified. Stable isotope ratios of carbon (δ ¹³ C) and nitrogen (δ ¹⁵ N) recorded in organisms have been widely used for identifying dietary carbon and nitrogen sources in food webs and for estimating trophic positions (TPs). Compound-specific isotope analysis (CSIA) of nitrogen within amino acids (AAs) provides a highly precise approach for identifying the dietary nitrogen sources and TPs. The δ ¹⁵ N values of phenylalanine (δ ¹⁵ N _Phe ) in organisms reflect those in their diets, while differences in the δ ¹⁵ N values between glutamic acid (δ ¹⁵ N _Glu ) and phenylalanine (Δ ¹⁵ N _Glu-Phe ) reflect the TP of the organism (TP _Glu/Phe ). Since the conversion from Δ ¹⁵ N _Glu-Phe to TP _Glu/Phe varies depending on the contribution of nitrogen from vascular plants, comparing the ecologically estimated TP value (TP _est ), assigned based on feeding ecology, with TP _Glu/Phe allows for the back-calculation of the dietary nitrogen contribution from terrestrial ecosystems sustained by vascular plants. In this study, we analyzed δ ¹³ C and δ ¹⁵ N, in particular, conducted CSIA of nitrogen within AAs in animals inhabiting the salt marsh of the Obitsu River estuary located in Tokyo Bay. The results showed that bulk δ ¹³ C ranged from − 25.1 to − 13.9‰ and δ ¹⁵ N _Phe from 3.8 to 10.2‰, indicating that both aquatic algae and terrestrial vascular plants serve as ultimate dietary carbon and nitrogen sources. Furthermore, the comparison between TP _Glu/Phe and TP _est clearly demonstrated a substantial nitrogen contribution from terrestrial ecosystems to various salt marsh animals, and the overall dietary nitrogen contribution was estimated to be at least 30%. This study demonstrates the advantages of CSIA of nitrogen within AAs in elucidating the complex salt marsh food webs.