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Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene.

Kumaran NK, Padmalal D, Limaye RB, S VM, Jennerjahn T, Gamre PG - PLoS ONE (2016)

Bottom Line: Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant.The alarming rate of land modification and development is destabilizing these carbon pools resulting in large scale carbon emissions to the atmosphere and loss of low-latitude peat palaeorecords.Therefore, these palaeorecords are to be conserved and addressed for better understanding and utilizing the carbon pool for effective climate change adaptation.

View Article: PubMed Central - PubMed

Affiliation: Biodiversity and Palaeobiology Group, Palynology and Palaeoclimate Laboratory, Agharkar Research Institute, Pune-411004, India.

ABSTRACT
Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub-coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon-lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0-3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The alarming rate of land modification and development is destabilizing these carbon pools resulting in large scale carbon emissions to the atmosphere and loss of low-latitude peat palaeorecords. Therefore, these palaeorecords are to be conserved and addressed for better understanding and utilizing the carbon pool for effective climate change adaptation. This communication is the first attempt of addressing the peat formation and peatland development during the Holocene from the tropical region of Peninsular India.

No MeSH data available.


Related in: MedlinePlus

Land use / Land cover map of Greater Pamba River Basin (Achankovil, Pamba and Manimala rivers) showing locations of peat/wood deposits and borehole cores.
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pone.0154297.g001: Land use / Land cover map of Greater Pamba River Basin (Achankovil, Pamba and Manimala rivers) showing locations of peat/wood deposits and borehole cores.

Mentions: The Greater Pamba Basin (GPB) refers to the entire area drained by the Pamba, Manimala and Achankovil rivers is very important in socio—economic and cultural perspective of Kerala State in south-western India. Of the 44 rivers, Pamba had been the longest river in the erstwhile princely state of Travancore, but now is the third longest river in the state. Pamba River originates at Pulachimalai hill in the Peerumedu plateau (Idukki District) in the Western Ghats at an altitude of 1,650 m a.s.l. and flows through several places in Pathanamthitta and Alappuzha districts including Kuttanad, an important rice cultivating centre, before emptying into the Vembanad Lake. The basin extends over an area of 2,235 sq km with the entire catchment area limited to Kerala state and is bounded on the east by Western Ghats and on the west by Arabian Sea (Fig 1). The salient drainage characteristics of the Manimala and Achankovil rivers that form respectively the northern and southern boundaries are summarised in Table 1. In the highlands and eastern part of the midland, the rivers drain over a spectrum of rock types which include pyroxene granulites, charnockites and khondalites as the major constituents. Its course in the midland region (7.5 to 75 m above sea level) is mainly through laterites and Holocene sediments. In the lowland (< 7.5 m above sea level) the rivers flow through alluvial sands and clays of Holocene age. The rivers display dendritic and trellis drainage patterns in higher altitudes. On entering the coastal plains, the rivers take a northward trend and join the Vembanad Lake at Pallathuruthy near Alappuzha. The present northward trend in the lowlands has been caused by the silting of this water body coupled with a northward tilt during Late Pleistocene—Early Holocene [7–9].


Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene.

Kumaran NK, Padmalal D, Limaye RB, S VM, Jennerjahn T, Gamre PG - PLoS ONE (2016)

Land use / Land cover map of Greater Pamba River Basin (Achankovil, Pamba and Manimala rivers) showing locations of peat/wood deposits and borehole cores.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4862630&req=5

pone.0154297.g001: Land use / Land cover map of Greater Pamba River Basin (Achankovil, Pamba and Manimala rivers) showing locations of peat/wood deposits and borehole cores.
Mentions: The Greater Pamba Basin (GPB) refers to the entire area drained by the Pamba, Manimala and Achankovil rivers is very important in socio—economic and cultural perspective of Kerala State in south-western India. Of the 44 rivers, Pamba had been the longest river in the erstwhile princely state of Travancore, but now is the third longest river in the state. Pamba River originates at Pulachimalai hill in the Peerumedu plateau (Idukki District) in the Western Ghats at an altitude of 1,650 m a.s.l. and flows through several places in Pathanamthitta and Alappuzha districts including Kuttanad, an important rice cultivating centre, before emptying into the Vembanad Lake. The basin extends over an area of 2,235 sq km with the entire catchment area limited to Kerala state and is bounded on the east by Western Ghats and on the west by Arabian Sea (Fig 1). The salient drainage characteristics of the Manimala and Achankovil rivers that form respectively the northern and southern boundaries are summarised in Table 1. In the highlands and eastern part of the midland, the rivers drain over a spectrum of rock types which include pyroxene granulites, charnockites and khondalites as the major constituents. Its course in the midland region (7.5 to 75 m above sea level) is mainly through laterites and Holocene sediments. In the lowland (< 7.5 m above sea level) the rivers flow through alluvial sands and clays of Holocene age. The rivers display dendritic and trellis drainage patterns in higher altitudes. On entering the coastal plains, the rivers take a northward trend and join the Vembanad Lake at Pallathuruthy near Alappuzha. The present northward trend in the lowlands has been caused by the silting of this water body coupled with a northward tilt during Late Pleistocene—Early Holocene [7–9].

Bottom Line: Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant.The alarming rate of land modification and development is destabilizing these carbon pools resulting in large scale carbon emissions to the atmosphere and loss of low-latitude peat palaeorecords.Therefore, these palaeorecords are to be conserved and addressed for better understanding and utilizing the carbon pool for effective climate change adaptation.

View Article: PubMed Central - PubMed

Affiliation: Biodiversity and Palaeobiology Group, Palynology and Palaeoclimate Laboratory, Agharkar Research Institute, Pune-411004, India.

ABSTRACT
Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub-coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon-lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0-3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The alarming rate of land modification and development is destabilizing these carbon pools resulting in large scale carbon emissions to the atmosphere and loss of low-latitude peat palaeorecords. Therefore, these palaeorecords are to be conserved and addressed for better understanding and utilizing the carbon pool for effective climate change adaptation. This communication is the first attempt of addressing the peat formation and peatland development during the Holocene from the tropical region of Peninsular India.

No MeSH data available.


Related in: MedlinePlus