Nitrogen addition turns a temperate peatland from a near-zero source into a strong sink of nitrous oxide

Peatlands, as important global nitrogen (N) pools, are potential sources of nitrous oxide (N₂O) emissions. We measured N₂O flux dynamics in Hani peatland in a growing season with simulating warming and N addition for 12 years in the Changbai Mountains, Northeastern China, by using static chamber-gas chromatography. We hypothesised that warming and N addition would accelerate N₂O emissions from the peatland. In a growing season, the peatland under natural conditions showed near-zero N₂O fluxes and warming increased N₂O emissions but N addition greatly increased N₂O absorption compared with control. There was no interaction between warming and N addition on N₂O fluxes. Pearson correlation analysis showed that water table depth was one of the main environmental factors affecting N₂O fluxes and a positive relationship between them was observed. Our study suggests that the N₂O source function in natural temperate peatlands maybe not be so significant as we expected before; warming can increase N₂O emissions, but a high dose of N input may turn temperate peatlands to be strong sinks of N₂O, and global change including warming and nitrogen deposition can alter N₂O fluxes via its indirect effect on hydrology and vegetation in peatlands.

Patterns of nitrogen and phosphorus pools in terrestrial ecosystems in China

Recent increases in atmospheric carbon dioxide (CO2) and temperature relieve their limitations on terrestrial ecosystem productivity, while nutrient availability constrains the increasing plant photosynthesis more intensively. Nitrogen (N) and phosphorus (P) are critical for plant physiological activities and consequently regulate ecosystem productivity. Here, for the first time, we mapped N and P densities and concentrations of leaves, woody stems, roots, litter, and soil in forest, shrubland, and grassland ecosystems across China based on an intensive investigation at 4868 sites, covering species composition, biomass, and nutrient concentrations of different tissues of living plants, litter, and soil. Forest, shrubland, and grassland ecosystems in China stored 6803.6 Tg N, with 6635.2 Tg N (97.5 %) fixed in soil (to a depth of 1 m) and 27.7 (0.4 %), 57.8 (0.8 %), 71.2 (1 %), and 11.7 Tg N (0.2 %) in leaves, stems, roots, and litter, respectively. The forest, shrubland, and grassland ecosystems in China stored 2806.0 Tg P, with 2786.1 Tg P (99.3 %) fixed in soil (to a depth of 1 m) and 2.7 (0.1 %), 9.4 (0.3 %), 6.7 (0.2 %), and 1.0 Tg P (< 0.1 %) in leaves, stems, roots, and litter, respectively. Our estimation showed that N pools were low in northern China, except in the Changbai Mountains, Mount Tianshan, and Mount Alta, while relatively higher values existed in the eastern Qinghai–Tibetan Plateau and Yunnan. P densities in vegetation were higher towards the southern and north-eastern part of China, while soil P density was higher towards the northern and western part of China. The estimated N and P density and concentration datasets, “Patterns of nitrogen and phosphorus pools in terrestrial ecosystems in China” (https://doi.org/10.5061/dryad.6hdr7sqzx), are available from the Dryad digital repository (Zhang et al., 2021). These patterns of N and P densities could potentially improve existing earth system models and large-scale research on ecosystem nutrients.

Symbiosis Relationship and Symbiosis Quality Evaluation of Regional Tourism: A Case Study on the Greater Changbai Mountains Tourist Area

This paper aims to fully tap the value of the tourism brand of Changbai Mountains scenic area, give play to the radiation effect of the brand, and create the Greater Changbai Mountains (GCM) tourist area, thereby enhancing the coordinated development of regional tourism. Specifically, symbiosis correlation and symbiosis density were adopted to recognize the tourism symbiosis units in the core region of GCM tourist area, and an evaluation model was established for the tourism symbiosis quality in the core region of GCM tourist area. Based on the evaluation results, the places within the core region were divided into multiple levels. The results show that the core region of GCM tourist area covers Yanji City, Dunhua City, Hunchun City, Antu County, Baishan City, Fusong County, Changbai County, and Tonghua City, and these places fall on three different development levels.

Phialophora americana. [Descriptions of Fungi and Bacteria].

A description is provided for Phialophora americana (Herpotrichiellaceae, Chaetothyriales) found on decayed wood. Some information on its morphology, habitats, dispersal and transmission, conservation status and economic impacts is given, along with details of its geographical distribution (Antarctica, China (Changbai Mountains), Iran, Taiwan, Australia (Australian Capital Territory, New South Wales, Northern Territory, Queensland, South Australia, Victoria, Western Australia), Austria, Czech Republic, Estonia, Finland, France, Germany, Netherlands, Norway, Poland, Sweden, UK, Canada (New Brunswick, Northwest Territories), Mexico, USA (Minnesota, New York, Virginia, Wisconsin), Chile, Brazil (Parana, Pernambuco, Sao Paulo) and Uruguay) and associated organisms (man, woody plants and other wood-inhabiting fungi).