Flux of organic carbon burial and carbon emission from a large reservoir: implications for the cleanliness assessment of hydropower

Climatic and anthropogenic regulation of carbon transport and transformation in a karst river-reservoir system

“…The molar C:N ratio ranged from 4.7 to 8.9 (average = 6.6) in POC from the Maotiao cascade reservoirs of the Wujiang River (Liu et al, 2018). This indicates that autochthonous OM is an important component of organic matter in sediments, which is responsible for the variation of DIC with allochthonous terrestrial plant OM in the reservoirs (Wang et al, 2019b).…”

“…However, the degradation of organic matter is dominant in this area as indicated by the depletion of 13 C in the bottom region (Han et al, 2018;Wang et al, 2019c). DIC generated at the bottom of the reservoir will further promote the photosynthesis of surface water downstream of the reservoir via discharged water (f5, f6), and provide support for the degradation of organic matter (equation 4) at the bottom (Wang et al, 2019b;Lu et al, 2018).…”

“…While single reservoirs have many environmental consequences, the situation is more complex and potentially severe with cascade reservoirs. Past work has concentrated on the effects of reservoirs on greenhouse gases (Kumar et al, 2019 a,b;Maavara et al, 2019;Raymond et al, 2013;Wang et al, 2014a), the water regime (Wang et al, 2019a), sediment and carbon burial and carbon cycle (Bretier et al, 2019;Kondolf et al, 2018;Maavara et al, 2017;Wang et al, 2019b), water utilization and hydropower generation (Zhou et al, 2018), irrigation pressure and other ecological risks (Finer and Jenkins, 2012;Grill et al, 2015;Li et al, 2017;Nilsson et al, 2005; Van and Maavara, 2016;Watkins et al, 2019). DIC represents the largest fraction of total carbon in most rivers and is transported from the continents to the oceans (Meybeck, 1987;Brunet et al, 2009;McClanahan et al, 2016).…”

Vertical Divergence Characteristics of Dissolved Inorganic Carbon and Influencing Factors in a Karst Deep-Water Reservoir, Southwest China

“…Reservoirs play an important role in the exchange of matterand energy at the wateratmosphere interface [11], water-rock interface, and water-biological interface [12], as well as incarbon cycling and accumulation in watersheds [13], and they also play an important role in altering the carbon fluxes and pathways in reverie ecosystems [14]. In recent years, research on carbon cycling reservoirs has produced many results, for example, the exploration of computational methods and models for reservoir carbon fluxes [15,16], the assessment of the carbon sink effects of river-reservoir systems [17,18], the study ofthe effects of thermal stratification, biological pumps, and chemical stratification on carbon cycling [14,19,20]. Reservoirs carbon transport models have confirmed that complex biogeochemical changes occur within reservoirs [14,20], including the conversion of inorganic carbon to organic carbon by photosynthesis of aquatic organisms [21], the degradation and mineralization of organic matter to produce inorganic carbon [22], bacteria producing CH 4 under anaerobic or sulphuricconditions [23][24][25], and the degassing of dissolved inorganic carbon (DIC) to produce CO 2 [26,27].…”

“…DIC in reservoirs is from rock weathering, soil carbon loss [1,5], aquatic respiration [12], and water-air exchange [11]. The DIC concentration in a karst reservoir is significantly higher than in non-karst areas [17]. Aquatic plants can autotrophically convert DIC into organic carbon [21], some of which is permanently stored in the substrate and some of which is released into the atmosphere as CO 2 or CH 4 [22,34].…”