Seasonal variations and intricate diel differences in the physio-chemical parameters and CO2 emissions from a typical karst groundwater-fed reservoir in southern China

Li, Jianhong; Pu, Junbing; Zhang, Tao; Huang, Siyu; Yuan, Daoxian

doi:10.1007/s12665-019-8493-8

Cited by 8 publications

(2 citation statements)

References 46 publications

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“…When the rainy season floods, smaller amounts of surface water occasionally pour into the DLD reservoir from Dongguan Reservoir (Figure 1c). The mean depth of the DLD reservoir is 11 m, and the maximum depth is 22.5 m [25]. The DLD reservoir is stratified from early April to late October (late spring, summer and early autumn) and mixed at other times (autumn, winter and most of spring) [23].…”

Section: Study Areamentioning

confidence: 99%

Source, Distribution and Transformation of Organic Matter in a Subtropical Karst Reservoir

Li,

Zhang,

et al. 2023

Water

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In order to improve the understanding of the global carbon cycle and the stability of karst carbon sinks, it is necessary to better understand the source, distribution and transformation characteristics of organic matter (OM) in aquatic ecosystems. Here, stable isotope ratios (δ13C and δ15N), elemental analysis (C/N ratios), and lipid biomarkers were analyzed for dissolved organic matter (DOM) (<0.7 μm), particulate organic matter (POM) (>0.7 μm) of water, and organic matter from sediment cores (SCOM) to identify the sources, distribution, and transformation of OM in a subtropical karst reservoir. The results showed that short-chain (C14–20) n-alkyl lipids were more abundant than long-chain (C21–34) n-alkyl lipids in both the DOM and SCOM samples, indicating that bacteria were the primary sources of these lipids, while terrestrial organic matter (OM) made only a minor contribution to the n-alkyl lipid pool, and aquatic plants (macrophytes) OM contributed major contribution to the n-alkyl lipid pool in POM. Microbial activity and lipid degradation were more pronounced in the DOM. Furthermore, terrigenous and macrophyte-derived lipids were found to be more abundant in POM than in DOM and SCOM, suggesting that they are relatively resistant to degradation compared with phytoplankton-derived OM.

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Section: Study Areamentioning

confidence: 99%

Source, Distribution and Transformation of Organic Matter in a Subtropical Karst Reservoir

Li,

Zhang,

et al. 2023

Water

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“…There are few studies of GHG emissions from karst lakes, but notably fewer in tropical regions [28][29][30][31]. Very little is known about which variables control GHG emissions in karst lakes and how these lakes can give feedback or modulate climate change.…”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Concentration and Emissions along a Trophic Gradient in Tropical Karst Lakes

Vargas-Sánchez

Alcocer

Sánchez-Carrillo

et al. 2022

Water

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Inland aquatic ecosystems are valuable sentinels of anthropic-associated changes (e.g., agriculture and tourism). Eutrophication has become of primary importance in altering aquatic ecosystem functioning. Quantifying the CO2 emissions by inland aquatic ecosystems of different trophic statuses may provide helpful information about the role of eutrophication on greenhouse gas emissions. This study investigated diel and seasonal carbon dioxide (CO2) concentrations and emissions in three tropical karst lakes with different trophic statuses. We measured CO2 emissions using static floating chambers twice daily during the rainy/warm and dry/cold seasons while the lakes were thermally stratified and mixed, respectively. The CO2 concentration was estimated by gas chromatography and photoacoustic spectroscopy. The results showed a significant seasonal variation in the dissolved CO2 concentration (CCO2) and the CO2 flux (FCO2), with the largest values in the rainy/warm season but not along the diel cycle. The CCO2 values ranged from 13.3 to 168.6 µmol L−1 averaging 41.9 ± 35.3 µmol L−1 over the rainy/warm season and from 12.9 to 38.0 µmol L−1 with an average of 21.0 ± 7.2 µmol L−1 over the dry/cold season. The FCO2 values ranged from 0.2 to 12.1 g CO2 m−2 d−1 averaging 4.9 ± 4.0 g CO2 m−2 d−1 over the rainy/warm season and from 0.1 to 1.7 g CO2 m−2 d−1 with an average of 0.8 ± 0.5 g CO2 m−2 d−1 over the dry/cold season. During the rainy/warm season the emission was higher in the eutrophic lake San Lorenzo (9.1 ± 1.2 g CO2 m−2 d−1), and during the dry/cold the highest emission was recorded in the mesotrophic lake San José (1.42 ± 0.2 g CO2 m−2 d−1). Our results indicated that eutrophication in tropical karst lakes increased CO2 evasion rates to the atmosphere mainly due to the persistence of anoxia in most of the lake’s water column, which maintained high rates of anaerobic respiration coupled with the anaerobic oxidation of methane. Contrarily, groundwater inflows that provide rich-dissolved inorganic carbon waters sustain emissions in meso and oligotrophic karstic tropical lakes.

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Carbon balance model of groundwater-lake systems in arid and semi-arid areas and its application

Li,

Dong,

et al. 2025

CATENA

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Seasonal variations and intricate diel differences in the physio-chemical parameters and CO2 emissions from a typical karst groundwater-fed reservoir in southern China

Cited by 8 publications

References 46 publications

Source, Distribution and Transformation of Organic Matter in a Subtropical Karst Reservoir

Source, Distribution and Transformation of Organic Matter in a Subtropical Karst Reservoir

Carbon Dioxide Concentration and Emissions along a Trophic Gradient in Tropical Karst Lakes

Carbon balance model of groundwater-lake systems in arid and semi-arid areas and its application

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