Abstract The distribution and δ 13 C composition of n -alkanes were used to identify organic matt... more Abstract The distribution and δ 13 C composition of n -alkanes were used to identify organic matter (OM) sources in river dominated Ashtamudi Estuary, Southern India. A number of n -alkane indices have been calculated to illustrate the spatial variability by considering separately river dominated northern reaches and marine influenced southern part of the estuary. The carbon preference index (CPI) and average chain length (ACL) provide evidence for recycled organic inputs in the tidal zone, whereas dominant biogenic contribution has been observed in the riverine zone. The proxy ratio (P aq ) and terrigenous/aquatic ratio (TAR) indices demonstrate maximum aquatic productivity in the tidal dominated region of the Ashtamudi Estuary. The quantitative apportion of organic matter sources in Ashtamudi sediments using compound-specific carbon isotope analysis (CSIA) of long-chain n -alkane shows dominance (53–83%) of C 3 terrestrial plants derived OM. The results clearly demonstrate the effectiveness of an integrated molecular and stable carbon isotope analysis for quantitatively assessing OM sources in estuarine environments.
Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hi... more Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hill ranges in the southern part of India. We have studied geomorphic aspects of this river by examining longitudinal profiles and drainage pattern in order to understand the rock uplift and river incision. Chaliyar River and its tributaries display uneven longitudinal profiles with numerous knickpoints along the profiles. River concavity and river morphology were analysed to better understand the influence of tectonics and rock uplift on the fluvial and topographic system in the Chaliyar River basin. Wide variability in the concavity index of the tributaries of the Chaliyar River reflects the role of tectonism in carving the present river profiles. Steepness and concavity indices computed for the longitudinal profiles suggest that the rate of uplift is exceeding the rate of incision and are independent of lithology. River incision is not uniform in the Chaliyar River. The streams become graded (absence of knickpoints) towards the river mouth, suggesting that the uplift and incision are in equilibrium.
The distribution and δ 13 C composition of n-alkanes were used to identify organic matter (OM) ... more The distribution and δ 13 C composition of n-alkanes were used to identify organic matter (OM) sources in river dominated Ashtamudi Estuary, Southern India. A number of n-alkane indices have been calculated to illustrate the spatial variability by considering separately river dominated northern reaches and marine influenced southern part of the estuary. The carbon preference index (CPI) and average chain length (ACL) provide evidence for recycled organic inputs in the tidal zone, whereas dominant biogenic contribution has been observed in the riverine zone. The P aq and TAR indices demonstrate maximum aquatic productivity in the tidal dominated region of the Ashtamudi Estuary. The quantitative apportion of organic matter sources in Ashtamudi sediments using compound-specific carbon isotope analysis (CSIA) of long-chain n-alkane shows dominance (53–83%) of C 3 terrestrial plants derived OM. The results clearly demonstrate the effectiveness of an integrated molecular and stable carbon isotope analysis for quantitatively assessing OM sources in estuarine environments.
Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hi... more Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hill ranges in the southern part of India. We have studied geomorphic aspects of this river by examining longitudinal profiles and drainage pattern in order to understand the rock uplift and river incision. Chaliyar River and its tributaries display uneven longitudinal profiles with numerous knickpoints along the profiles. River concavity and river morphology were analysed to better understand the influence of tectonics and rock uplift on the fluvial and topographic system in the Chaliyar River basin. Wide variability in the concavity index of the tributaries of the Chaliyar River reflects the role of tectonism in carving the present river profiles. Steepness and concavity indices computed for the longitudinal profiles suggest that the rate of uplift is exceeding the rate of incision and are independent of lithology. River incision is not uniform in the Chaliyar River. The streams become graded (absence of knickpoints) towards the river mouth, suggesting that the uplift and incision are in equilibrium.
Abstract The distribution and δ 13 C composition of n -alkanes were used to identify organic matt... more Abstract The distribution and δ 13 C composition of n -alkanes were used to identify organic matter (OM) sources in river dominated Ashtamudi Estuary, Southern India. A number of n -alkane indices have been calculated to illustrate the spatial variability by considering separately river dominated northern reaches and marine influenced southern part of the estuary. The carbon preference index (CPI) and average chain length (ACL) provide evidence for recycled organic inputs in the tidal zone, whereas dominant biogenic contribution has been observed in the riverine zone. The proxy ratio (P aq ) and terrigenous/aquatic ratio (TAR) indices demonstrate maximum aquatic productivity in the tidal dominated region of the Ashtamudi Estuary. The quantitative apportion of organic matter sources in Ashtamudi sediments using compound-specific carbon isotope analysis (CSIA) of long-chain n -alkane shows dominance (53–83%) of C 3 terrestrial plants derived OM. The results clearly demonstrate the effectiveness of an integrated molecular and stable carbon isotope analysis for quantitatively assessing OM sources in estuarine environments.
Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hi... more Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hill ranges in the southern part of India. We have studied geomorphic aspects of this river by examining longitudinal profiles and drainage pattern in order to understand the rock uplift and river incision. Chaliyar River and its tributaries display uneven longitudinal profiles with numerous knickpoints along the profiles. River concavity and river morphology were analysed to better understand the influence of tectonics and rock uplift on the fluvial and topographic system in the Chaliyar River basin. Wide variability in the concavity index of the tributaries of the Chaliyar River reflects the role of tectonism in carving the present river profiles. Steepness and concavity indices computed for the longitudinal profiles suggest that the rate of uplift is exceeding the rate of incision and are independent of lithology. River incision is not uniform in the Chaliyar River. The streams become graded (absence of knickpoints) towards the river mouth, suggesting that the uplift and incision are in equilibrium.
The distribution and δ 13 C composition of n-alkanes were used to identify organic matter (OM) ... more The distribution and δ 13 C composition of n-alkanes were used to identify organic matter (OM) sources in river dominated Ashtamudi Estuary, Southern India. A number of n-alkane indices have been calculated to illustrate the spatial variability by considering separately river dominated northern reaches and marine influenced southern part of the estuary. The carbon preference index (CPI) and average chain length (ACL) provide evidence for recycled organic inputs in the tidal zone, whereas dominant biogenic contribution has been observed in the riverine zone. The P aq and TAR indices demonstrate maximum aquatic productivity in the tidal dominated region of the Ashtamudi Estuary. The quantitative apportion of organic matter sources in Ashtamudi sediments using compound-specific carbon isotope analysis (CSIA) of long-chain n-alkane shows dominance (53–83%) of C 3 terrestrial plants derived OM. The results clearly demonstrate the effectiveness of an integrated molecular and stable carbon isotope analysis for quantitatively assessing OM sources in estuarine environments.
Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hi... more Chaliyar River, a west-flowing river, originates at about 2300 m elevation in the Western Ghat hill ranges in the southern part of India. We have studied geomorphic aspects of this river by examining longitudinal profiles and drainage pattern in order to understand the rock uplift and river incision. Chaliyar River and its tributaries display uneven longitudinal profiles with numerous knickpoints along the profiles. River concavity and river morphology were analysed to better understand the influence of tectonics and rock uplift on the fluvial and topographic system in the Chaliyar River basin. Wide variability in the concavity index of the tributaries of the Chaliyar River reflects the role of tectonism in carving the present river profiles. Steepness and concavity indices computed for the longitudinal profiles suggest that the rate of uplift is exceeding the rate of incision and are independent of lithology. River incision is not uniform in the Chaliyar River. The streams become graded (absence of knickpoints) towards the river mouth, suggesting that the uplift and incision are in equilibrium.
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