Effects of habitat fragmentation on genetic diversity and gene flow among the Homidia socia (Collembola: Entomobryidae) populations in the Thousand Island Lake

In the present study, partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene of 22 island populations of the springtail Homidia socia in the Thousand Island Lake were sequenced. Across all sequences, 37 haplotypes were identified for the 510‐bp mitochondrial (mt) DNA COI gene. Haplotype 2 was the most common, and was distributed in the most of the 22 island populations. Haplotype diversity ranged from 0.065 to 0.733, and the total genetic diversity was 0.56216. The genetic characteristics of the 22 island populations were analyzed using the fixation index and gene flow, with values of 0.00043–0.94900 and 0.02703–703.72540, respectively. Comparison between (island area and isolations) with population genetic diversity revealed that there were no significant correlations between them, except for a significant correlation between the number of haplotypes and island area. Mantel tests showed that there was no significant correlation between geographic distance and genetic distance among various groups. All the results indicated that there were no obvious relationships between island characteristics and the genetic diversity of the springtails. We consider that the low dispersal capacity of springtails and the island patches surrounded by water in the Thousand Island Lake are the major factors affecting the genetic diversity of H. socia.     

A new species of Macrophya Dahlbom (Hymenoptera: Tenthredinidae) with a key to species of the Macrophya coxalis group from China

A new species, Macrophyra pseudocoxalis Li, Liu & Wei, sp. nov., of the genus Macrophya Dahlbom (Hymenptera: Tenthredinidae) from China is described. A key to known Chinese species of the Macrophya coxalis group is provided. The type specimens of the new species are deposited in the Lishui Academy of Forestry, Lishui, Zhejiang, China.     

Effects of wildfire on soil respiration and its heterotrophic and autotrophic components in a montane coniferous forest

Aims Episodic wildfires are expected to occur more frequently under future climate change scenarios, with substantial effects on CO₂exchange between terrestrial ecosystems and the atmosphere. This study examined the effects of wildfire on soil respiration (R_S) and its heterotrophic (R_H) and autotrophic (R_A) components, as well as their temperature responses (temperature sensitivity,Q₁₀).     

The first chromosome‐level genome for a marine mammal as a resource to study ecology and evolution

Marine mammals are important models for studying convergent evolution and aquatic adaption, and thus reference genomes of marine mammals can provide evolutionary insights. Here, we present the first chromosome‐level marine mammal genome assembly based on the data generated by the BGISEQ‐500 platform, for a stranded female sperm whale (Physeter macrocephalus). Using this reference genome, we performed chromosome evolution analysis of the sperm whale, including constructing ancestral chromosomes, identifying chromosome rearrangement events and comparing with cattle chromosomes, which provides a resource for exploring marine mammal adaptation and speciation. We detected a high proportion of long interspersed nuclear elements and expanded gene families, and contraction of major histocompatibility complex region genes which were specific to sperm whale. Using comparisons with sheep and cattle, we analysed positively selected genes to identify gene pathways that may be related to adaptation to the marine environment. Further, we identified possible convergent evolution in aquatic mammals by testing for positively selected genes across three orders of marine mammals. In addition, we used publicly available resequencing data to confirm a rapid decline in global population size in the Pliocene to Pleistocene transition. This study sheds light on the chromosome evolution and genetic mechanisms underpinning sperm whale adaptations, providing valuable resources for future comparative genomics.     

Effects of Codonopis bulleynana forest ex diels on Deferribacteres in constipation predominant intestine tumor: Differential analysis

As a complicated micro-ecosystem, gut microbes are closely related to metabolic disease, immune disease and tumor (such as constipation. Long-term constipation would cause intestinal mucosal injury, enteritis, ileus, etc., thus inducing intestine cancer). In this research, intestine cancer model group and Codonopsis foetens treatment group were successfully constructed, and the variation of intestinal microbes were analyzed by 16S rRNA sequence. Results showed that there were changes in bacteria abundance of Firmicutes, Bacteroidetes, Proteobacteria, Deferribacteres, Tenericutes, and Actinobacteria, etc. Codonopsis foetens could directly or indirectly affect the growth and metabolism of Deferribacteres by altering the nutritional ingredient and pH value of intestine “medium”, thus affecting the occurrence and development of intestinal microbes.     

Long‐term changes in the impacts of global warming on leaf phenology of four temperate tree species

Contrary to the generally advanced spring leaf unfolding under global warming, the effects of the climate warming on autumn leaf senescence are highly variable with advanced, delayed, and unchanged patterns being all reported. Using one million records of leaf phenology from four dominant temperate species in Europe, we investigated the temperature sensitivities of spring leaf unfolding and autumn leaf senescence (S_T, advanced or delayed days per degree Celsius). The S_T of spring phenology in all of the four examined species showed an increase and decrease during 1951–1980 and 1981–2013, respectively. The decrease in the S_T during 1981–2013 appears to be caused by reduced accumulation of chilling units. As with spring phenology, the S_T of leaf senescence of early successional and exotic species started to decline since 1980. In contrast, for late successional species, the S_T of autumn senescence showed an increase for the entire study period from 1951 to 2013. Moreover, the impacts of rising temperature associated with global warming on spring leaf unfolding were stronger than those on autumn leaf senescence. The timing of leaf senescence was positively correlated with the timing of leaf unfolding during 1951–1980. However, as climate warming continued, the differences in the responses between spring and autumn phenology gradually increased, so that the correlation was no more significant during 1981–2013. Our results further suggest that since 2000, due to the decreased temperature sensitivity of leaf unfolding the length of the growing season has not increased any more. These finding needs to be addressed in vegetation models used for assessing the effects of climate change.     

Global ammonia emissions from synthetic nitrogen fertilizer applications in agricultural systems: Empirical and process‐based estimates and uncertainty

Excessive ammonia (NH₃) emitted from nitrogen (N) fertilizer applications in global croplands plays an important role in atmospheric aerosol production, resulting in visibility reduction and regional haze. However, large uncertainty exists in the estimates of NH₃ emissions from global and regional croplands, which utilize different data and methods. In this study, we have coupled a process‐based Dynamic Land Ecosystem Model (DLEM) with the bidirectional NH₃ exchange module in the Community Multiscale Air‐Quality (CMAQ) model (DLEM‐Bi‐NH₃) to quantify NH₃ emissions at the global and regional scale, and crop‐specific NH₃ emissions globally at a spatial resolution of 0.5° × 0.5° during 1961–2010. Results indicate that global NH₃ emissions from N fertilizer use have increased from 1.9 ± 0.03 to 16.7 ± 0.5 Tg N/year between 1961 and 2010. The annual increase of NH₃ emissions shows large spatial variations across the global land surface. Southern Asia, including China and India, has accounted for more than 50% of total global NH₃ emissions since the 1980s, followed by North America and Europe. Rice cultivation has been the largest contributor to total global NH₃ emissions since the 1990s, followed by corn and wheat. In addition, results show that empirical methods without considering environmental factors (constant emission factor in the IPCC Tier 1 guideline) could underestimate NH₃ emissions in context of climate change, with the highest difference (i.e., 6.9 Tg N/year) occurring in 2010. This study provides a robust estimate on global and regional NH₃ emissions over the past 50 years, which offers a reference for assessing air quality consequences of future nitrogen enrichment as well as nitrogen use efficiency improvement.     

Climate warming alters subsoil but not topsoil carbon dynamics in alpine grassland

Subsoil contains more than half of soil organic carbon (SOC) globally and is conventionally assumed to be relatively unresponsive to warming compared to the topsoil. Here, we show substantial changes in carbon allocation and dynamics of the subsoil but not topsoil in the Qinghai‐Tibetan alpine grasslands over 5 years of warming. Specifically, warming enhanced the accumulation of newly synthesized (¹⁴C‐enriched) carbon in the subsoil slow‐cycling pool (silt‐clay fraction) but promoted the decomposition of plant‐derived lignin in the fast‐cycling pool (macroaggregates). These changes mirrored an accumulation of lipids and sugars at the expense of lignin in the warmed bulk subsoil, likely associated with shortened soil freezing period and a deepening root system. As warming is accompanied by deepening roots in a wide range of ecosystems, root‐driven accrual of slow‐cycling pool may represent an important and overlooked mechanism for a potential long‐term carbon sink at depth. Moreover, given the contrasting sensitivity of SOC dynamics at varied depths, warming studies focusing only on surface soils may vastly misrepresent shifts in ecosystem carbon storage under climate change.     

Behavior of the extremophile green alga Coccomyxa melkonianii SCCA 048 in terms of lipids production and morphology at different pH values

Extremophiles - The extremophile green alga Coccomyxa melkonianii SCCA 048 was investigated to evaluate its ability to grow in culture media with different pH. Specifically, Coccomyxa melkonianii...