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Copyright of Journal of Nanjing University of Information Science & Technology (Natural Science Edition) / Nanjing Xinxi Gongcheng Daxue Xuebao (ziran kexue ban) is the property of Editorial Office of Journal of Nanjing University of Information Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Greenhouse gases released by lakes are considered important and are underestimated sources of greenhouse gas emissions. Methane is an important component of greenhouse gas emissions from lakes. Previous studies have shown that the CH4 production and oxidation processes in lake ecosystems are mainly controlled by the activities of methanogens and methane-oxidizing bacteria in water bodies and sediments. Factors such as water temperature, pH, dissolved oxygen concentration, and nutritional status may affect the CH4 emission flux in lakes. This study used the Web of Science and CNKI as search platforms to investigate the CH4 emission flux at the water air interface of 80 lakes in different regions of the world. The results showed that the CH4 emission flux was 2.56 mmol·m-2 ·d-1 (ranging from 0.001 to 40.3 mmol·m-2 ·d-1 ). The CH4 emission flux from lakes in South America and Europe was significantly higher than that of lakes in Africa, and the CH4 emissions from eutrophic lakes to the atmosphere was significantly higher than that from medium and poornutrient lakes. Lakes with an area of less than 1 km² emitted significantly more CH4 into the atmosphere than lakes with an area of 10 km² to 100 km² and lakes with an area of more than 100 km² . The release of CH4 into the atmosphere from lakes in low altitude areas was significantly higher than that from lakes in high altitude areas and lakes at ultra-high altitudes. Methane emissions into the atmosphere by lakes in summer was significantly higher than that in spring, autumn, and winter. During the warm season, eutrophication in low altitude areas and small shallow lakes were hot spots for CH4 emissions. In the future, further integration of microbial production and CH4 oxidation mechanisms and strengthening of research on daily variation is needed to estimate CH4 emission flux to provide a scientific basis for studying the amount of CH4 emissions from lakes considering global climate change. [ABSTRACT FROM AUTHOR]

To explore the effects of different CO2 concentrations and nitrogen fertilizer levels on the respiration rate of paddy fields, a field experiment was conducted using 12 open-top chambers. Three levels of CO2 concentration were set: the control(CK, ambient atmospheric CO2 concentration), and CO2 concentrations increased by 120 μmol·mol-1 (C1)and 200 μmol·mol-1 (C2)compared with CK. Nitrogen fertilizer was set at two levels: low nitrogen application(N1, 15 g·m-2 )and conventional nitrogen fertilizer(N2, 25 g·m-2 ), with a total of 6 treatments in the experiment. The results showed that under the same nitrogen application level, the respiration rate of the C1N1 treatment decreased by 23.4%(P=0.045)and 49.1%(P=0.010)compared with the CKN1 treatment at the filling stage and wax ripening stage, respectively. During the heading and grain-filling stages, the respiration rates of the C2N2 treatment increased by 12.3%(P=0.009)and 16.8%(P=0.047)compared with the CKN2 treatment, respectively. Under the same level of CO2 concentration, the respiration rates of different nitrogen application levels showed that N2>N1 and showed a significant level during the elongation and heading stages and an extremely significant level during the grain filling stage. In the grain filling and wax ripening stages, the respiration rates of C1N1 treatment decreased by 31.1%(P=0.004)and 42.7%(P=0.010), respectively, compared with C1N2 treatment. This paper demonstrates that the effect of elevated atmospheric CO2 concentration on the respiration rate of paddy fields varies with the growth period, and nitrogen fertilizer reduction can reduce the respiration rate and CO2 accumulation in paddy fields. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)