Carbon and Nitrogen Burial and Response to Climate Change and Anthropogenic Disturbance in Chaohu Lake, China

Abstract

Lakes are a crucial component of the global carbon and nitrogen cycle. As a trend of enhanced human activities and climate change, the mechanisms of burial remain poorly understood. In this study, diverse biogeochemical techniques were applied to analyze the temporal variation of organic carbon and nitrogen burial rates in Chaohu Lake. The results showed that burial rates have ranged from 9.39 to 35.87 g C m−2 yr−1 for carbon and from 1.66 to 5.67 g N m−2 yr−1 for nitrogen since the 1860s. The average rates were 19.6 g C m−2 yr−1 and 3.14 g N m−2 yr−1 after the 1970s, which were significantly higher than the rate before the 1970s, showing an increasing trend. The decrease of C/N ratios as well as organic matter δ13C values indicates that the major organic matter source in sediment has been algal production since the 1970s. The increase of δ15N values indicated that the promotion in productivity was stimulated by nutrient input from sewage and agricultural runoff. The burial rates of organic carbon and nitrogen were significantly positively related to socio-economics and temperature, indicating that Chaohu Lake will become an increasing carbon and nitrogen pool under conditions of enhanced human activities and intensive precipitation.

Seasonal Release Potential of Sediments in Reservoirs and its Impact on Water Quality Assessment

“…As an important component of the reservoir water environment, sediments have the contradictory characteristics of “source–sink” for pollutants. During the long operation period of a reservoir, sediments have been receivers of various pollutants including point and nonpoint sources [1,2]. With the perennial accumulation of pollutants and mineralization of sedimentary organic matter, concentrations of a variety of constituents in sediments are many times greater than those in water.…”

Synergistic Impacts of Climate Change and Human Activities on Spatiotemporal Organic Nitrogen Burial Variation in a Plateau Lake in Southwest China

“…A previous study indicated that only approximately 20% of pollutants are discharged via Dianchi Lake processes while the rest remain in the sediment, allowing them to be easily released into the overlying water again (He et al, 2015). This phenomenon is one of the reasons for the higher ON content (294-6140 mg kg − 1 ) in Dianchi Lake sediment than in other eutrophic lake sediments, such as Chaohu Lake (195-1076 mg kg − 1 ) and Taihu Lake (278-4687 mg kg − Loading [MathJax]/jax/output/CommonHTML/fonts/TeX/fontdata.js 1 ) (Yu et al, 2018;Wu et al, 2019). In addition, the speci c conditions of the sediment core sampling region affect ON burial.…”

Synergistic impacts of climate change and human activities on spatiotemporal organic nitrogen burial variation in a plateau lake in southwest China

“…It accumulates in the sediment and is easily converted to nitrate and ammonia via mineralization. Most of the converted ammonium and nitrate are released into the overlying water, which may cause algal blooms (Galman et al, 2008;Yu et al, 2018). The effects of algal residues, which are considered important autochthonous sources, on organic matter burial have been widely studied (Anderson et al, 2014;Leithold et al, 2016).…”