Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, PR China.
Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, PR China.
Environ Res. 2023 Jun 15;227:115753. doi: 10.1016/j.envres.2023.115753. Epub 2023 Mar 23.
Lake eutrophication seriously threatens water quality and human health. Under continuous global warming and intensified human activity, increasing attention is being paid to how lake trophic status responds to climate change and anthropogenic impacts. Based on the sedimentary organic matter (SOM) molecular composition determined by the Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) technology, and combined with the SOM stable nitrogen isotopes (δN), we studied how lake trophic status and ecology respond to both climatic changes and anthropogenic impacts of the past 500 yrs at Lake Daihai, Inner Mongolia. The results show that the relative abundance of lipids, proteins, and carbohydrates in lake sediments kept relatively low before AD ∼1850, and increased gradually thereafter, especially after AD ∼1950, suggesting that the lake trophic status was low before AD ∼1850, but obviously increased during the past one more century. On the other hand, the relative abundance of allochthonous condensed aromatics and vascular plant-derived polyphenols compounds gradually decreased after AD ∼1850, which is most likely due to the intensified land-use changes in the catchment. Our results show that the SOM molecular composition is more sensitive to trace the land-use changes than the δN ratios, suggesting a potential use of this technique to trace even earlier human land uses (e.g., during the prehistorical times) in a catchment. The results of this study suggest that intensified land-use change, increased discharges of human sewage and industrial wastewater, cropland runoff, and concentrated effects caused by lake level drops may have combinedly increased nutrient concentration and accelerated lake eutrophication at Lake Daihai. Therefore, proper policy is necessary to slow down anthropogenic impacts and limit further eutrophication for lakes like Lake Daihai.
湖泊富营养化严重威胁着水质和人类健康。在全球持续变暖以及人类活动加剧的情况下，人们越来越关注湖泊营养状态如何应对气候变化和人为影响。本研究基于傅里叶变换离子回旋共振质谱（FT-ICR MS）技术测定的沉积有机质（SOM）分子组成，并结合 SOM 稳定氮同位素（δN），研究了过去 500 年来内蒙古岱海的湖泊营养状态和生态系统如何对气候变化和人为影响做出响应。结果表明，AD∼1850 年前，湖泊沉积物中脂质、蛋白质和碳水化合物的相对丰度一直保持在较低水平，此后逐渐增加，特别是 AD∼1950 年后，表明 AD∼1850 年前湖泊营养状态较低，但在过去一个多世纪明显增加。另一方面，AD∼1850 年后，异源缩合芳烃和维管束植物衍生多酚化合物的相对丰度逐渐减少，这很可能是由于集水区土地利用的加剧变化。我们的结果表明，SOM 分子组成比δN 比值更能灵敏地追踪土地利用变化，表明该技术具有潜在的用途，可以追踪集水区更早的人类土地利用（例如史前时期）。本研究结果表明，加剧的土地利用变化、人类污水和工业废水排放量的增加、农田径流以及湖泊水位下降造成的浓缩效应可能共同增加了营养物质浓度，加速了岱海的富营养化。因此，需要采取适当的政策来减缓人为影响，限制像岱海这样的湖泊进一步富营养化。
