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| Spatial-temporal distribution of organic matter in surface sediments of Caohai wetland in Weining, Guizhou Province, China |
| Received:May 27, 2021 |
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| KeyWord:Caohai Lake wetland;organic matter;carbon isotope(δ13C);nitrogen isotope(δ15N);source |
| Author Name | Affiliation | E-mail | | LI Linwei | School of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
Key Laboratory of Karst Geological Resources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China | | | WU Pan | School of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
Key Laboratory of Karst Geological Resources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China | | | CAO Xingxing | School of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
Key Laboratory of Karst Geological Resources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China | xxcao@gzu.edu.cn | | YANG Shidi | School of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
Key Laboratory of Karst Geological Resources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China | | | LIU Shan | School of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
Key Laboratory of Karst Geological Resources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China | | | LIAO Jiahao | School of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China
Key Laboratory of Karst Geological Resources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China | |
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| Abstract: |
| To explore the nutritional status and pollutant sources of the ecological environment of karst wetlands, the distribution of total organic carbon(TOC)with total nitrogen(TN), including stable carbon isotopes(δ13C), nitrogen isotopes(δ15N), and C / N ratios, were studied in the surface sediments of the Caohai Lake karst wetland in Weining, Guizhou Province; then, the distribution characteristics and sources of organic matter in sediments were discussed. The results showed that the TOC and TN contents varied from 3.75% to 32.71% and 0.39% to 2.90% in the wet season, with average values of 14.34% and 1.52%, respectively. The TOC and TN contents ranged from 1.26% to 34.11% and 0.18% to 2.49% in the dry season, with average values of 12.46% and 1.12%, respectively. The TOC and TN contents in the high water period were slightly higher than those in the dry season, which was related to the land source input caused by increased rainfall during the high water period. Meanwhile, regarding the spatial distribution, the concentrations of TOC and TN in the southwest and the lake center region were greater than those in the east and northwest regions in both seasons. Regarding surface sediments in the Caohai Lake wetland, the distribution of δ13C, δ15N ranged from -2.55% to -1.97% and from 0.03% to 0.37% in the wet season, with average values of -2.23% and 0.24%, respectively. The distribution of δ13C and δ15N ranged from -2.75% to -1.96% and 0.10% to 0.46% in the dry season, with average values of -2.35% and 0.30%, respectively. The spatial distribution of δ13C in the eastern area was significantly lower as compared to the western area, which indicated that the eastern area was seriously polluted. This was because the eastern area was adjacent to the county, the source of pollutants was complex, the submerged plants were destroyed, and the productivity of the lake itself was reduced. The end member mixed model was used to qualitatively and semi-quantitatively analyze the sediment sources. The results showed that the main sources of organic matter in the surface sediments of the Caohai Lake wetland were soil organic matter, planktonic algae, and freshwater aquatic plants. At the same time, due to the high primary productivity of the Caohai Lake karst wetland, the contribution of organic matter in the sediments from internal sources was greater than that from exogenous inputs. |
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