A high-resolution climate simulation dataset for the past 540 million years.

The Phanerozoic Eon has witnessed considerable changes in the climate system as well as abundant animals and plant life. Therefore, the evolution of the climate system in this Eon is worthy of extensive research. Only by studying climate changes in the past can we understand the driving mechanisms for climate changes in the future and make reliable climate projections. Apart from observational paleoclimate proxy datasets, climate simulations provide an alternative approach to investigate past climate conditions of the Earth, especially for long time span in the deep past. Here we perform 55 snapshot simulations for the past 540 million years, with a 10-million-year interval, using the Community Earth System Model version 1.2.2 (CESM1.2.2). The climate simulation dataset includes global distributions of monthly surface temperatures and precipitation, with a 1° horizontal resolution of 0.9° × 1.25° in latitude and longitude. This open access climate dataset is useful for multidisciplinary research, such as paleoclimate, geology, geochemistry, and paleontology.

Cracking the superheavy pyrite enigma: possible roles of volatile organosulfur compound emission.

The global deposition of superheavy pyrite (pyrite isotopically heavier than coeval seawater sulfate in the Neoproterozoic Era and particularly in the Cryogenian Period) defies explanation using the canonical marine sulfur cycle system. Here we report petrographic and sulfur isotopic data (δ34Spy) of superheavy pyrite from the Cryogenian Datangpo Formation (660-650 Ma) in South China. Our data indicate a syndepositional/early diagenetic origin of the Datangpo superheavy pyrite, with 34S-enriched H2S supplied from sulfidic (H2S rich) seawater. Instructed by a novel sulfur-cycling model, we propose that the emission of 34S-depleted volatile organosulfur compounds (VOSC) that were generated via sulfide methylation may have contributed to the formation of 34S-enriched sulfidic seawater and superheavy pyrite. The global emission of VOSC may be attributed to enhanced organic matter production after the Sturtian glaciation in the context of widespread sulfidic conditions. These findings demonstrate that VOSC cycling is an important component of the sulfur cycle in Proterozoic oceans.

Active methanogenesis during the melting of Marinoan snowball Earth.

Geological evidence indicates that the deglaciation of Marinoan snowball Earth ice age (~635 Myr ago) was associated with intense continental weathering, recovery of primary productivity, transient marine euxinia, and potentially extensive CH4 emission. It is proposed that the deglacial CH4 emissions may have provided positive feedbacks for ice melting and global warming. However, the origin of CH4 remains unclear. Here we report Ni isotopes (δ60Ni) and Yttrium-rare earth element (YREE) compositions of syndepositional pyrites from the upper most Nantuo Formation (equivalent deposits of the Marinoan glaciation), South China. The Nantuo pyrite displays anti-correlations between Ni concentration and δ60Ni, and between Ni concentration and Sm/Yb ratio, suggesting mixing between Ni in seawater and Ni from methanogens. Our study indicates active methanogenesis during the termination of Marinoan snowball Earth. This suggests that methanogenesis was fueled by methyl sulfides produced in sulfidic seawater during the deglacial recovery of marine primary productivity.

Five-year change in body mass index category of childhood and the establishment of an obesity prediction model.

The prevalence of childhood obesity in China has recently become increasingly severe, and intervention measures are needed to stop its growth. Currently, there is a lack of assessment and prediction methods for childhood obesity. We develop a predictive model that uses currently measured predictors [gender, age, urban/rural, height and body mass index (BMI)] to quantify children's probabilities of belonging to one of four BMI category 5 years later and identify the high-risk group for possible intervention. A total of 88,980 students underwent a routine standard physical examination and were reexamined 5 years later to complete the study. The full model shows that boys, urban residence and height have positive effects and that age has a negative effect on transition to the overweight or obese category along with significant BMI effects. Our model correctly predicts BMI categories 5 years later for 70% of the students. From 2018 to 2023, the prevalence of obesity in rural boys and girls is expected to increase by 4% and 2%, respectively, while that in urban boys and girls is expected to remain unchanged. Predictive models help us assess the severity of childhood obesity and take targeted interventions and treatments to prevent it.