Export fluxes of dissolved inorganic carbon to the Northern Indian Ocean from the Indian monsoonal rivers

Krishna, M. S.; Viswanadham, R.; Prasad, M.H.K.; Kumari, V R; Sarma, V. V. S. S.

doi:10.5194/bg-2018-4

Cited by 4 publications

(11 citation statements)

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“…Furthermore, the chemical weathering processes can be altered easily through changing hydrological conditions (Gareis & Lesack, 2017; Torres, West, & Clark, 2015; Zhong et al, 2018). Although numerous studies of chemical weathering and CO 2 consumption rate have been carried out on rivers worldwide (Amiotte Suchet, Probst, & Ludwig, 2003; Gaillardet et al, 1999; Galy & France‐Lanord, 1999; Krishna, Viswanadham, Prasad, Kumari, & Sarma, 2018; Li et al, 2010; Li, Calmels, Han, Gaillardet, & Liu, 2008; Louvat & Allègre, 1997; Millot, Gaillardet, Dupré, & Allègre, 2002; Ollivier, Hamelin, & Radakovitch, 2010; Rai, Singh, & Krishnaswami, 2010; Roy, Gaillardet, & Allegre, 1999), few were devoted to temporal chemical weathering processes, and fewer still focused on the effects of hydrological variability on chemical weathering processes in monsoonal rivers.…”

Section: Introductionmentioning

confidence: 99%

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

Liu

Zhong

Ding

et al. 2020

Hydrological Processes

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To better understand the mechanisms relating to hydrological regulations of chemical weathering processes and dissolved inorganic carbon (DIC) behaviours, high-frequency sampling campaigns and associated analyses were conducted in the Yu River, SouthChina. Hydrological variability modifies the biogeochemical processes of dissolved solutes, so major ions display different behaviours in response to discharge change. Most ions become diluted with increasing discharge because of the shortened reactive time between rock and water under high-flow conditions. Carbonate weathering is the main source of major ions, which shows strong chemostatic behaviour in response to changes in discharge. Ions from silicate weathering exhibit a significant dilution effect relative to the carbonate-sourced ions. Under high temperatures, the increased soil CO 2 influx from the mineralisation of organic material shifts the negative carbon isotope ratios of DIC (δ 13 C DIC ) during the high-flow season. The δ 13 C DIC values show a higher sensitivity than DIC contents in response to various hydrological conditions. Results from a modified isotope-mixing model (IsoSource) demonstrate that biological carbon is a dominant source of DIC and plays an important role in temporal carbon dynamics. Furthermore, this study provides insights into chemical weathering processes and carbon dynamics, highlighting the significant influence of hydrological variability to aid understanding of the global carbon cycle.

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Section: Introductionmentioning

confidence: 99%

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

Liu

Zhong

Ding

et al. 2020

Hydrological Processes

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“…During the dry season, δ 13 CDIC varied between -5.07 and -3.24‰ (mean: -3.78 ± 0.86‰) in the BB estuaries with peak values in the Matla estuary (Fig. 3C & 3D; Dutta et al, 2019aDutta et al, , 2021Krishna et al, 2019).…”

Section: Dic and δ 13 Cdic Variabilitymentioning

confidence: 99%

“…Carbonate mineral weathering has been shown to be an important contributor to the DIC pool of Indian estuaries based on observed δ 13 CDIC -TAlk relationships (significantly positive; r 2 = 0.52, p <0.01; Krishna et al, 2019). Despite higher chemical weathering in the Deccan Trap basalts (Das et al, 2005;Singh et al, 2005) that occupied the catchments of north western rivers and upper reaches of the Godavari and Krishna, a larger DIC is reported in rivers draining over metamorphic rock landscapes.…”

Section: Chemical Weathering Precipitation and Physiography Of Indian...mentioning

confidence: 99%

“…Further, the abundance of thermogenic sources of CH4 in tectonically active estuarine seafloors remain poorly documented and potentially large positive feedback for climate change (Johnson et al, 2022).The coast of India is home to numerous and diverse estuarine systems facing varying degrees of anthropogenic pressure; to date, studies of Indian estuaries have largely focused on either single estuaries with wide spatial coverage (Mukhopadhyay et al., 2006;Samanta et al, 2015;Dutta et al, 2019aDutta et al, , 2021Gupta et al, 2008;Pattanaik et al, 2017;Bhavya et al, 2017;Bouillon et al, 2003;Sarma et al, 2011), or a large number of estuaries with limited sampling locations (Sarma et al, 2012(Sarma et al, , 2014Krishna et al, 2015Krishna et al, , 2019Rao et al, 2016). Moreover, many of these estuaries have extensive coastal wetlands, particularly mangroves, which are densely distributed in estuaries of the Sundarbans (Saptamukhi, Thakuran, and Matla) and more sparsely scattered along the banks of the Haldia, Mahanadi, Godavari, Krishna, Ponnayaar, Mandovi and Zuari Rivers (Dutta et al, 2015;Rao et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…In general, the C biogeochemistry of Indian estuaries bordered by extensive mangrove systems, has received more attention than estuaries less influenced by mangroves (Biswas et al, 2004(Biswas et al, , 2007Mukhopadhyay et al, 2002;Dutta et al, 2013Dutta et al, , 2015Dutta et al, , 2017Dutta et al, , 2019aDutta et al, , 2019bDutta et al, , 2021Ray et al, 2011Ray et al, , 2013Ray et al, , 2015Ray et al, , 2018Ganguly et al, 2011;Krithika et al, 2008;Borges et al, 2003;Akhand et al, 2016Akhand et al, , 2021. Some studies have focused on key drivers of OM cycling (Sarma et al, 2012(Sarma et al, , 2014Dutta et al, 2019aDutta et al, , 2021Rao et al, 2016;Ray et al, 2011Ray et al, , 2013Biswas et al, 2004Biswas et al, , 2007Mukhopadhyay et al, 2002), and others more on quantitative assessments of C budgets (Dutta et al, 2013(Dutta et al, , 2015(Dutta et al, , 2017 and export fluxes (Ray et al, 2018;Krishna et al, 2015Krishna et al, , 2019. Nevertheless, there remain gaps in our knowledge on how changes in seasons (wet vs. dry) and marginal seas (Bay of Bengal BB vs. Arabian Sea AS) fit into the larger view of estuarine C processing in the dynamic coastal region.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reviews and Syntheses: Carbon biogeochemistry of Indian estuaries

Dutta

Sreelash²,

Padmalal³

et al. 2022

Preprint

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Abstract. The goal of this review is to provide a comprehensive overview of the magnitude and drivers of carbon cycling dynamics in the major estuaries of India. Data from a total of 32 estuaries along the Bay of Bengal (BB) and the Arabian Sea (AS) were compiled from the literature and re-analysed based on changes in season (wet vs. dry) and marine end-members (e.g., BB vs. AS). The estuaries are generally undersaturated in dissolved oxygen relative to the atmosphere and strongly influenced by local and regional precipitation patterns. Speciation of the dissolved inorganic carbon (DIC) pool is dominated by bicarbonate and primarily variability in DIC is controlled by a combination of carbonate weathering, the degree of precipitation, the length of the estuaries, in situ respiration, and mixing. Carbonate dissolution had the largest influence on DIC during the wet season, while respiration was the primary control of DIC variability in the estuaries connected with BB during the dry season. Interestingly, the influence of anaerobic metabolism on DIC is observed in the oxygenated mangrove dominated estuaries, which we hypothesize is driven by porewater exchange in intertidal sediments. Dissolved organic carbon (DOC) generally behaves non-conservatively in the studied estuaries. The DOC-particulate organic carbon (POC) inter-conversion and DOC mineralization are evident in the BB during the dry season and AS estuaries, respectively. The wet season δ13CPOC shows dominance of freshwater algae, C3 plant material, as well as marine organic matter in POC. However, anthropogenic inputs are evident in some estuaries in eastern India during the dry season. POC respiration was identified in the AS; however, a link between POC and CH4 is identified throughout both the regions. pCO2 is controlled principally by respiration with freshwater discharge only playing a marginal important role in the BB. The AS estuaries act as a CO2 source to the atmosphere; however, the BB estuaries vary between a source and sink. POC together with methanotrophy and dam abundance appear to control CH4 concentrations, and all of the studied estuaries act as a CH4 source to the atmosphere. Additionally, anthropogenic inputs and groundwater exchange also show potential influences in some cases. The Indian estuaries contribute 2.62 % and 1.09 % to the global riverine DIC and DOC exports to the ocean, respectively. The total CO2 and CH4 fluxes from Indian estuaries are estimated as ~9718 Gg yr-1 and 3.27 Gg yr-1, which contributes ~0.67 % and ~0.12 %, respectively, to global estimates of estuarine greenhouse gas emissions. While a qualitative idea on the major factors controlling the carbon biogeochemistry in India is presented through this work, a more thorough investigation including rate quantification of the above-mentioned mechanisms is essential for precise accounting of the C budget of Indian estuaries.

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Tracing solute sources and carbon dynamics under various hydrological conditions in a karst river in southwestern China

Liu

Chen

et al. 2020

Environ Sci Pollut Res

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Export fluxes of dissolved inorganic carbon to the Northern Indian Ocean from the Indian monsoonal rivers

Cited by 4 publications

References 0 publications

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

Reviews and Syntheses: Carbon biogeochemistry of Indian estuaries

Tracing solute sources and carbon dynamics under various hydrological conditions in a karst river in southwestern China

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