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| 洱海大气氮素湿沉降特征 |
| Characteristics of Atmospheric Nitrogen Wet Deposition in Erhai Lake |
| 投稿时间：2021-03-19 修订日期：2021-06-08 |
| DOI：10.14050/j.cnki.1672-9250.2021.49.091 |
| 中文关键词: 大气氮 湿沉降 时空分布 洱海 |
| 英文关键词: atmospheric nitrogen wet deposition temporal and spatial distribution Erhai Lake |
| 基金项目:大理州州财政项目（2019532900000519）。 |
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| 中文摘要: |
| 通过对2020年位于洱海湖区周边4个站点大气降水的实地监测，定量揭示了大气湿沉降不同形态氮素（TN、DTN、AN、NN、NIT、PN）的浓度和时空分布规律，探讨了氮素沉降通量的变化特征及其主要影响因子，进而明确了大气氮湿沉降对湖区外源性氮素输入的贡献程度，评估了氮素湿沉降入湖负荷对湖区水环境的影响。结果表明：各监测点降水中氮素浓度年内总体呈先升后降再升的趋势，总氮浓度为0.18～8.73 mg/L，平均浓度为1.34±0.686 mg/L，氮素浓度呈现干季高湿季低的变化规律；氮素湿沉降通量月际变化大致呈M双峰型，沉降通量峰值出现在浓度最低但降雨量最大的8月，最小值出现在12月，沉降通量与降雨量呈极显著正相关，沉降通量AN/NN为1.97，农业生产活动的氮素排放是湿沉降的主要来源；2020年洱海湖面湿沉降总氮直接输入负荷量约为170.11 t，其中铵态氮86.86 t，硝态氮51.58 t，总氮直接入湖负荷约占流域农业面源排放量的6.18%。 |
| 英文摘要: |
| Through the field monitoring of atmospheric precipitation at four stations located in the surrounding area of Erhai Lake in 2020, the concentration and temporal and spatial distribution of different forms of atmospheric wet deposition nitrogen (total nitrogen, total dissolved nitrogen, ammonia nitrogen, nitrate nitrogen, nitrous nitrogen, particulate nitrogen) were quantitatively revealed, and the temporal variation of nitrogen deposition flux and its main influencing factors were discussed, and then the contribution of atmospheric nitrogen wet deposition to exogenous nitrogen input in the lake area was clarified, and the impact of nitrogen wet deposition load into the lake on the water environment of the lake area was evaluated. The results showed that the nitrogen concentration in the precipitation at each monitoring point showed a trend of first rising, then falling and then rising during the year. The total nitrogen concentration ranged from 0.18 to 8.73 mg/L, and the average concentration was 1.34±0.686 mg/L. The nitrogen concentration presents a trend of high in dry seasons and low in wet seasons; the monthly variation of nitrogen wet deposition flux manifested a roughly "M" bimodal, and the precipitation flux peak appeared in August when the nitrogen concentration was lowest but the rainfall was highest, and the minimum flux appeared in December. The deposition flux was extremely positively correlated with rainfall. The deposition flux ratio of ammonium nitrogen to nitrate nitrogen was 1.97, indicating that nitrogen emissions from agricultural production activities were the main source of wet deposition; The direct wet deposit input load of total nitrogen was about 170.11 tons in Erhai Lake in 2020, including 86.86 tons of ammonium nitrogen and 51.58 tons of nitrate nitrogen. The direct load of total nitrogen from wet deposition into the lake accounted for about 6.18% of the agricultural non-point source emissions in the basin. |
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