The roles of phosphate in shaping the structure and dynamics of Antarctic soil microbiomes

One major consequence of global warming in the Antarctic region is increased ice-free zones.Subsequent colonization of these ice-free areas by penguins alters their biogeochemistry,with one prominent example being elevation of inorganic phosphate concentrations around feces depositions.The complex soil biochemistry in the region makes it difficult to define the causal factors of these changes using common research approaches.Here,we addressed the effects of phosphate alone on microbiome structure and dynamics over time by adding external phosphate to selected soils in the Antarctic region.We then analyzed the soil bacterial community composition and diversity using 16S rRNA amplicon sequencing and compared these data with phosphate levels.Parallel geochemical analysis revealed changes in nine soil geochemical factors upon phosphate addition,all of which were relevant to microbiome structure,with soil pH showing the highest correlation.Links between geochemical factors and composition were identified,as were interactions between bacterial taxa.Additionally,Sphingobacteriia,Sphingobacteriales and Chitinophagaceae were found to be more abundant in phosphate-treated soils.Co-occurrence network analysis revealed significantly increased levels of associations in all major network properties over time after phosphate supplementation.Therefore,we conclude phosphate addition has diverse effects on Antarctic soil microbiomes.

Thermally Dependent Behaviour of Cold-Blooded Animals: Overcoming Two Temperature Barriers on the Way to Warm-Blooded

Background: The temperature preferences of cold-blooded animals are different for different groups of animals and are closely related to their evolutionary status and level of adaptive capabilities. The range of preferred temperatures for reptiles (28°C - 32°C) coincides with the zone of temperature-dependent increase in the rate of the M-cholinergic reaction in the brain, which was previously found in warm-blooded neurons. The growth of the M-cholinergic process contributes to the transition of adaptive behavior to a higher level. Of the cold-blooded, only reptiles actively use thermoregulatory behavior as a tool to achieve a temperature optimum. This paper is devoted to the study of the behavior of red-eared turtles aimed at reaching the range of preferred temperatures. Temperature conditions necessary for the survival of different groups of cold-blooded animals are compared and the reason for temperature preferences is discussed. Methods: The behavior of turtles was studied under conditions of variable solar radiation and in a 3-section terrarium with gradual temperature ranges: 23°C - 24°C;28°C - 31°C and 45°C - 50°C. Results: It was found that prolonged (up to 1.5 hours) heating at a temperature of 45°C - 50°C was the best way to achieve the preferred temperatures. This method of heating results in increasing the temperature of the shell to an average of 37°C, followed by a very slow decrease during 4 - 6 hours within the limits that closely coincided with the preferred level. Conclusion: The results obtained demonstrate that the main function of the turtle shell is to accumulate heat and keep it for a long time in a variable climate. The preferred temperature achieved in this case is necessary for the temperature-dependent transition of the rate of the M-cholinergic reaction in the brain to a higher level, which creates more significant adaptive capabilities. The temperature range of the M-cholinergic process has two inflection points at 27°C - 29°C and 34°C - 36°C. In accordance with these values, the temperature preferences of cold-blooded animals are divided into three groups: 0°C - 28°C (fish and amphibians);28°C - 32°C (reptiles) and 34°C - 36°C (dinosaurs). Different ranges of preferred temperatures correspond to three stages of adaptive development.

Model Projections of East Asian Summer Climate under the ‘Free Arctic’ Scenario

This paper addresses the ‘ice-free Arctic’ issue under the future global warming scenario. Four coupled climate models used in the third phase of the Coupled Model Intercomparison Project (CMIP3) were selected to project summer climate conditions over East Asia once the Arctic becomes ice-free. The models project that an ice-free Arctic summer will begin in the 2060s under the SRESA1B (according to IPCC Special Reports on Emissions Scenarios) simulations. Our results show that the East Asian summer monsoons will tend to be stronger and that the water vapor transport to central northern China will be strengthened, leading to increased summer precipitation in central northern China. The models also project an intensified Antarctic Oscillation, a condition which favors increased precipitation in South China’s Yangtze River Valley. The overall precipitation in Northwest China is projected to increase under ice-free Arctic summer conditions.