Water, rather than temperature, dominantly impacts how soil fauna affect dissolved carbon and nitrogen release from fresh litter during early litter decomposition

Longstanding observations suggest that dissolved materials are lost from fresh litter through leaching, but the role of soil fauna in controlling this process has been poorly documented. In this study, a litterbag experiment employing litterbags with different mesh sizes (3 mm to permit soil fauna access and 0.04 mm to exclude fauna access) was conducted in three habitats (arid valley, ecotone and subalpine forest) with changes in climate and vegetation types to evaluate the effects of soil fauna on the concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) during the first year of decomposition. The results showed that the individual density and community abundance of soil fauna greatly varied among these habitats, but Prostigmata, Isotomidae and Oribatida were the dominant soil invertebrates. At the end of the experiment, the mass remaining of foliar litter ranged from 58% for shrub litter to 77% for birch litter, and the DOC and TDN concentrations decreased to 54%-85% and increased to 34%-269%, respectively, when soil fauna were not present. The effects of soil fauna on the concentrations of both DOC and TDN in foliar litter were greater in the subalpine forest (wetter but colder) during the winter and in the arid valley (warmer but drier) during the growing season, and this effect was positively correlated with water content. Moreover, the effects of fauna on DOC and TDN concentrations were greater for high-quality litter and were related to the C/N ratio. These results suggest that water, rather than temperature, dominates how fauna affect the release of dissolved substances from fresh litter

The complete mitochondrial genome of Plagiopholis styani (Reptilia: Squamata: Colubridae)

In this study, the complete mitochondrial genome of Plagiopholis styani was acquired and described. The mitogenome is a circular molecule of 19,669 base pairs (bp) in length including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and two control regions (D-loop), which is similar to other Colubridae snakes. The total base composition of mitochondrial DNA is A 33.0%, C 24.9%, G 12.8%, and T 29.3%. The mitochondrial genome of Plagiopholis styani contributes to revealing the phylogenetic relationships among species of the Colubridae family

The complete mitochondrial genome of white-tailed mole (Parascaptor leucura)

The white-tailed mole (Parascaptor leucura) belongs to genus Parascaptor, which is a monotypic genus distributed across Southwestern China, Assam (India), Bengal, and Northern Burma, and Laos. In this study, we obtained the complete mitochondrial genome of Parascaptor leucura. The genome is total 16,875 bp in length, containing 13 protein-coding genes, 22 transfer RNA genes (tRNA), two ribosomal RNA genes (rRNA), and two non-coding regions, with a base composition of 33.5% A, 26.4% T, 25.7% C, and 14.3% G. The nucleotide sequence data of 13 protein-coding genes of P. leucura and other nine Eulipotyphla species were used to reconstruct a Bayesian phylogenetic tree. The tree shows that P. leucura belongs to subfamily Talpinae and is closely related to Scaptochirus moschatus

The complete mitogenome of Smith’s shrew (Chodsigoa smithii)

The Smith’s shrew (Chodsigoa smithii) belongs to subfamily Soricinae, which is an endemic shrew to China. In this study, we obtained the complete mitochondrial genome of the C. smithii. This mitogenome is a circular molecule with 17,108 bp in length, containing 13 protein-coding genes, 22 transfer RNA genes, two ribosome RNA genes, one light strand replication origin (OL), one non-coding region, and with a base composition of 32.5% A, 29.3% T, 24.8% C, and 13.4% G. The nucleotide sequence data of 13 protein-coding genes of C. smithii and other 19 Soricomorpha species were used for phylogenetic analyses. Phylogenetic tree shows that Soricinae includes two major phylogenetic lineages. Chodsigoa smithii is located as a basal position in tribe Nectogalini

Climate, plant organs and species control dissolved nitrogen and phosphorus in fresh litter in a subalpine forest on the eastern Tibetan Plateau

International audienceAbstractKey messageFresh litter contains a higher concentration of dissolved phosphorus (DP) than dissolved nitrogen (DN), which implies a more efficient DN transformation or reabsorption in the subalpine forest on the eastern Tibetan Plateau. Both DN and DP concentrations increased with the increase of mean monthly temperature, although the concentrations were also regulated by plant organs and species.ContextThe dissolved nitrogen (DN) and dissolved phosphorus (DP) released from fresh litter are important pathways by which total nitrogen and phosphorus are transferred from the vegetation to soil in forest ecosystems. However, few studies have paid attention to the DN and DP in fresh litter, which affects our understanding of the nitrogen and phosphorus cycles.AimsThe objectives of this study were to elucidate the dynamic characteristics of the concentrations and storage of DN and DP, and to analyze how DN and DP are affected by different plant species and organs, and climate factors.MethodsFresh litter was collected in three plots in a spruce-fir forest and classified by different plant species and organs. Concentration and storage of DN and DP in fresh litter were determined and related to the climatic variables that were monthly recorded.ResultsThe concentration of DP was higher than that of DN in fresh litter, and the concentrations of both elements were determined by plant organs and species. Moreover, The DN and DP concentration was positively related to mean monthly temperature, while DN and DP storage was negatively correlated with mean monthly temperature and monthly precipitation. The storage of DN and DP was determined by litter biomass, which the order in litter from different plant organs was leaves>twigs>miscellaneous>flowers and fruits. The storage of DN and DP in leaves showed two peaks in April and October, but that in twigs and the miscellaneous showed only one peak in October.ConclusionOur results indicated that dissolved nitrogen (DN) is transferred and reabsorbed more than dissolved phosphorus (DP) before plant leaf senescence and other organs fall. Furthermore, DN and DP were associated with climate, plant organs and species in a subalpine forest on the eastern Tibetan Plateau

Stress corrosion cracking behavior of X80 pipeline steel under alternating current, Desulfovibrio desulfurican and cathodic protection potential

The stress corrosion cracking (SCC) behavior of X80 pipeline steel under Desulfovibrio desulfurican (D. desulfurican), alternating current (AC) and cathodic protection (CP) was studied by the constant load tests and slow strain rate tensile (SSRT) test. The results showed that both AC interference and relatively negative CP potential aggravated pitting corrosion and enhanced the SCC susceptibility under the constant load. In the saline soil environment containing D. desulfurican, the AC greatly contributed to the cracking tendency of X80 pipeline steel and resulted in the safe CP range that was too narrow for practical engineering application, thus requiring appropriate discharge methods

The complete mitochondrial genome of Amphiesma optatum

In this study, we obtained and described the complete mitochondrial genome sequence of Amphiesma optatum. The total length is 17,259 base pairs. Similar to most Colubridae mitochondrial genomes, there are 37 genes including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), and 2 ribosomal RNA genes (rRNA). In addition, it contains two control regions (D-loop) rich in A–T base. The total base composition of mitochondrial DNA is 34.3% for A, 26.5% for C, 12.8% for G, and 26.4% for T, and the percentage of GC content is 39.3%. These data further reveal the phylogenetic relationship between Amphiesma optatum and other species in the Colubridae family

Initial Carbon Quality of Newly Shed Foliar Litter in an Alpine Forest from Proximate Analysis and 13C NMR Spectroscopy Perspectives

The initial carbon (C) quality of plant litter is one of the major factors controlling the litter decomposition rate and regulating C sequestration, but a comprehensive understanding is still lacking. Here, we used proximate analysis and 13C nuclear magnetic resonance (NMR) with spectral editing techniques to quantify the variations in the initial C quality for four dominant species (fir: Abies faxoniana Rehd. et Wils.; spruce: Picea asperata Mast; willow: Salix paraplesia Schneid; and rosa: Rosa omeiensis Rolfe.), including the organic compositions and C-based chemical structures of newly shed foliar litter over eight months in an alpine forest on the eastern Tibetan Plateau. The results indicated that the fractions of acid-soluble extractives (ASE) and acid-unhydrolyzable residues (AUR) were the main fractions of organic components, and aliphatic C and O-alkyl C were the main functional C groups for all plant species. Under the effects of the plant species, higher levels of ASE (37.62%) and aliphatic C (35.44%) were detected in newly shed rosa foliar litter, while higher levels of AUR (fir: 37.05%; spruce: 41.45%; and willow: 40.04%) and O-alkyl C (fir: 32.03%; spruce: 35.02%; and willow: 32.34%) were detected in newly shed fir, spruce and willow foliar litter. Moreover, the A/O-A and HB/HI ratios in rosa litter were 0.88 and 1.15, respectively, which were higher than those in fir, spruce and willow litter. The C quality of newly shed foliar litter varied seasonally due to the litter quality and environmental conditions, especially nitrogen (N), dissolved organic carbon (DOC), manganese (Mn) and monthly air temperature. We also found that C loss during 4-year litter decomposition was highly related to the aromatic C and phenolic C contents in newly shed foliar litter, suggesting that litter decomposition was strongly controlled by the initial recalcitrant C fractions. We conclude that the C quality of newly shed foliar litter in rosa might be structurally stable and more resistant to degradation than that of fir, spruce and willow, which contain abundant labile C fractions, and the initial recalcitrant C fractions are closely related to C loss during litter decomposition, which might contribute to soil C sequestration in alpine forests

The complete mitochondrial genome of Omei Treefrog (Rhacophorus omeimontis)

In this study, the complete mitochondrial genome of Rhacophorus omeimontis was obtained and described. The sequenced mitogenome is total 19,604 base pairs (bp) in length, which contained 13 protein-coding genes (PCGS), 22 transfer RNA genes (tRNA), 2 ribosomal RNA genes (rRNA), and 2 control regions (D-loop). The overall base composition of the mitochondrial DNA is 32.5% for A, 30.5% for T, 23.3% for C, and 13.7% for G, and the percentage of GC content is 37.0%. The complete mitochondrial genome information of R. omeimontis will contribute to revealing the phylogenetic relationships among species of family Rhacophoridae

The complete mitochondrial genome of Pseudoxenodon macrops

In this study, we obtained the complete mitochondrial genome of Pseudoxenodon macrops. The sequenced mitogenome is 20,978 base pairs(bp) in length, which contained 13 protein-coding genes (PCGS), 22 transfer RNA genes (tRNA), 2 Ribosomal RNA genes (rRNA) and 2 control regions (D-loop). The total base composition of mitochondrial DNA is that A, C, G and T occupied 33.1%, 26.6%, 12.8% and 26.5%, respectively. The mitochondrial genome of Pseudoxenodon macrops will help us reveal phylogenetic relationships among the species of the Colubridae family