Sources and distribution of organic matter in thirty five tropical estuaries along the west coast of India-a preliminary assessment

Pradhan, U.K.; Wu, Ying; Shirodkar, P.V.; Zhang, Jing; Zhang, Guosen

doi:10.1016/j.ecss.2014.09.010

Cited by 49 publications

(15 citation statements)

References 43 publications

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“…Terrestrial C 3 plants have more depleted δ 13 C values closer to ‐25 to ‐28‰, and soil OM display values from ‐27.5 to ‐29.5‰ (Pasqual, Calafat, Lopez‐Fernandez, & Pusceddu, ; Tesi et al, ). Terrestrial C 3 plants are dominant in the Netravati River basin and contribute to the possible source of OM, as reported by Pradhan, Wu, Shirodkar, Zhang, and Zhang (). The values obtained are within the ranges for terrestrial and aquatic environments, which are between ‐25 and ‐30‰ in runoff originating from terrestrial source (Cifuentes et al, ; Wu, Zhang, Li, Wei, & Lu, ).…”

Section: Discussionmentioning

confidence: 59%

Spatial and temporal variations in source, diagenesis, and fate of organic matter in sediments of the Netravati River, India

Fernandes

Shirodkar

et al. 2019

Hydrological Processes

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Organic matter (OM) such as organic nitrogen plays a substantial role in the global biogeochemical cycling of bio‐reactive components—amino acids (AA) in aquatic environments. Spatial and temporal variations in source, diagenesis, and fate of organic nitrogen such as AA in sediments of small tropical rivers and the role of oxbow/meandering loops under changing climatic conditions are poorly investigated. This study assessed the spatial and seasonal variations in OM composition, source, and diagenesis of a tropical small mountainous river—Netravati River, India, for 1 year. Water samples were determined for suspended particulate matter, and surface sediments were examined for bulk parameters, surface area (SA), and the L‐ and D‐enantiomers of AA. The L‐ and D‐enantiomers of AA displayed subtle seasonal variations in composition and depicted varying degrees of diagenesis. The concentration of D‐enantiomer of AA was high and showed substantial contributions from bacteria, terrestrial source, and in situ production. The D‐arginine was the most abundant D‐enantiomer of AA in the study area, possibly due to extracellular secretion by bacterial species and adsorption onto sediments, and thus, it was protected from degradation. Degradation index was more negative at the oxbow and meandering loop stations during the dry season suggesting that local geomorphologic settings steer the diagenesis of OM within the river. A negative relationship between gamma‐aminobutyric acid and organic carbon:surface area (OC:SA) ratio and a positive correlation between tyrosine and OC:SA ratio suggested accelerated loss of OM. Furthermore, the concentrations of most bulk parameters were higher in the lower reaches during monsoon and premonsoon seasons. Taken together, changes in seasons have an operational control in distinguishing the composition, source, and diagenesis of spatial OM distribution. Moreover, oxbows and river meandering loops influence the diagenetic processes in small tropical river systems.

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Section: Discussionmentioning

confidence: 59%

Spatial and temporal variations in source, diagenesis, and fate of organic matter in sediments of the Netravati River, India

Fernandes

Shirodkar

et al. 2019

Hydrological Processes

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“…Table 3 summarizes the distribution of bulk and lignin parameters from typical systems worldwide. Although the TOC values of our studied systems are compared lower with peat samples but the concentrations of lignin phenols are comparable, which are typically enriched in lignin phenols compared with other river systems (Table 3; Bianchi et al, 2002;Gandois et al, 2014;Li et al, 2015;Sun et al, 2017;Pradhan et al, 2014;Winterfeld et al, 2015). The TN values of our peat samples are between two and four times higher than those seen in other systems worldwide, as was also observed in small rivers along India's west coast (Pradhan et al, 2014).…”

Section: Discussionmentioning

confidence: 67%

“…Elevated soil turnover rates, coupled with short water residence times in small tropical river catchments, lead to the accelerated transformation of terrestrial organic matter (OM), especially during highdischarge events (Bao et al, 2015;Goldsmith et al, 2008;Kao and Liu, 1996). Anthropogenic processes such as deforestation have been a major cause of altered hydrology and OM compositions in tropical river systems (Houghton et al, 2000;Jennerjahn et al, 2004Jennerjahn et al, , 2008Pradhan et al, 2014). The current paucity of information on OCterr characteristics and its export by rivers from tropical peat-draining rivers remains a major gap in our understanding of OCterr biogeochemical cycling in rivers from tropical Southeast Asia.…”

Section: Introductionmentioning

confidence: 99%

Distribution and degradation of terrestrial organic matter in the sediments of peat-draining rivers, Sarawak, Malaysian Borneo

Wu¹,

Zhang²,

Müller³

et al. 2019

Preprint

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Abstract. Tropical peatlands are one of the largest pools of terrestrial organic carbon (OCterr); however, our understanding of the dynamics of OCterr in peat-draining rivers remains limited, especially in Southeast Asia. This study used bulk parameters and lignin phenols concentrations to investigate the characteristics of OCterr in a tropical peat-draining river system (the main channel of the Rajang and three smaller rivers) in the western part of Sarawak, Malaysian Borneo. The depleted &#948;13C levels and lignin composition of the organic matter indicates that the most important plant source of the organic matter in these rivers is woody angiosperm C3 plants, especially in the three small rivers sampled. The diagenetic indicator ratio (i.e., the ratio of acid to aldehyde of vanillyl phenols (Ad&#8201;/&#8201;Al)v) increased with decreasing mean grain size of sediment from the small rivers. The selective sorption of acid relative to aldehyde might explain the variations in the (Ad&#8201;/&#8201;Al)v ratio. The (Ad&#8201;/&#8201;Al)v ratio appears to be related to the C&#8201;/&#8201;N ratio (the ratio of total organic carbon to total nitrogen) in the Rajang and small rivers, where slower degradation of OCterr and a higher total nitrogen percentage (TN%) were observed, compared to other river systems. Most of the OCterr discharged from the Rajang and small river systems was material derived from woody angiosperm plants with limited diagenetic alteration before deposition, and so could potentially provide significant carbon to the atmosphere after degradation.

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“…This finding is in line with the work of Prasad et al (2007) and Sardessai (1994), who reported terrestrial dominated organic matter in the mid and outer eastern Arabian shelf sediments. Recently, Pradhan et al (2014) documented the sources and distributions of organic matters of Netravati and Gurpur estuaries and reported the dominance of plant organic matter having TOC:TN ratio ranging from 10 to 30 (Pradhan et al, 2014, Fig . 3).…”

Section: Nature Of Organic Mattersmentioning

confidence: 96%

Response of trace metal redox proxies in continental shelf environment: The Eastern Arabian Sea scenario

Acharya

Panigrahi

Gupta

et al. 2015

Continental Shelf Research

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Sources and distribution of organic matter in thirty five tropical estuaries along the west coast of India-a preliminary assessment

Cited by 49 publications

References 43 publications

Spatial and temporal variations in source, diagenesis, and fate of organic matter in sediments of the Netravati River, India

Spatial and temporal variations in source, diagenesis, and fate of organic matter in sediments of the Netravati River, India

Distribution and degradation of terrestrial organic matter in the sediments of peat-draining rivers, Sarawak, Malaysian Borneo

Response of trace metal redox proxies in continental shelf environment: The Eastern Arabian Sea scenario

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