Biogeochemical records of paleoenvironmental changes in Nainital Lake, Kumaun Himalayas, India

Choudhary, Preetam; Routh, Joyanto; Chakrapani, G. J.; Kumar, Bhishm

doi:10.1007/s10933-009-9306-y

Cited by 27 publications

(26 citation statements)

References 64 publications

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“…Typically, OM produced by cyanobacteria in eutrophic lakes has δ 15 N values of -3‰ to 1‰, especially under conditions of high P-flux and N-limited conditions (Brenner et al 1999;Talbot 2001 Evidently, the lake had a mixed phytoplankton community in the water column, which gradually changed to a system dominated by cyanobacteria as nutrient input increased after the 1960s (see below). The same trend is observed in other Kumaon lakes (Choudhary et al 2009a, b), indicating the impact of human-induced processes on phytoplankton in these remote mountain lakes.…”

supporting

confidence: 82%

“…Therefore, bulk  13 C values of sediment OM are mostly unreliable as source indicators in lacustrine systems (Meyers 1997(Meyers , 2003. Together with other geochemical variables, however, the  13 C values can be useful in tracking OM sources and ongoing biogeochemical processes in lakes (Routh et al 2004Choudhary et al 2009a (Meyers 1997(Meyers , 2003. Thus, elemental accumulation rates,  13 C (-24.6‰ to -29.9‰) and δ 15 N (-0.2‰ to 3.3‰) values in these sediments indicate an algal-dominated OM source, which has not changed over the last 100+ years in Lake Bhimtal.…”

Section: Organic Matter Sourcesmentioning

confidence: 99%

“…This is evident from increasing levels of environmental pollutants in the atmosphere, surface water and aquifers, and soils in this region (Chakrapani 2002;Das 2005). For example, lakes in the Kumaon region have undergone changes during the last few decades that have affected water quality, increasing heavy metal content and algal productivity (Chakrapani 2002;Das 2005;Choudhary et al 2009a, b). Remedial measures were undertaken by the local authorities (Kumar 2007), but were largely restricted to Lake Nainital, located in the heart of the city.…”

Section: Introductionmentioning

confidence: 99%

“…These lakes respond quickly to natural or human-induced perturbations in their catchments. The effects of these perturbations are potentially recorded in sediments, which can be used for reconstructing past conditions over different timescales (Battarbee et al 2002;Vreča and Muri 2006;Choudhary et al 2009a, b). Preservation of sediment organic matter (OM) in these lakes is usually high (Vreča and Muri 2006;Choudhary et al 2009a, b) because of multiple processes, including high productivity, rapid sedimentation, and anoxic conditions on the lake bottom (Meyers 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Understanding the past and ongoing biogeochemical processes in these mountain lakes, which result from anthropogenic activities and/or climate changes, is vital for implementing restoration methods and sustainable management practices. We also compare the paleoenvironmental history of Lake Bhimtal with other mountain lakes in the Kumaon region (Chakrapani 2002;Das 2005;Choudhary et al 2009aChoudhary et al , b, 2010, and formulate general conclusions regarding the status of these vulnerable water bodies.…”

Section: Introductionmentioning

confidence: 99%

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A 100-year record of changes in organic matter characteristics and productivity in Lake Bhimtal in the Kumaon Himalaya, NW India

2012

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Sediment variables total organic carbon (TOC), total nitrogen (TN), total sulfur (TS), as well as their accumulation rates and atomic ratios (C/N and C/S), were studied along with stable isotopes (δ 13 C, δ 15 N, and δ 34 S), and specific biomarkers (n-alkanes and pigments) in a 35-cm-long sediment core from Lake Bhimtal, NW India. The average sedimentation rate is 3.6 mm yr -1 , and the core represents a provisional record of 100 years of sedimentation history. Bulk elemental records and their ratios indicate that sediment organic matter (OM) is derived primarily from algae. In-lake productivity increased sharply over the last two decades, consistent with paleoproductivity reconstructions from other lakes in the area. An up-core decrease in δ 13 C values, despite other evidence for an increase in lake productivity, implies that multiple biogeochemical processes (e.g. reflect the presence of N-fixing cyanobacteria, and an increase in lake productivity. The  34 S profile shows enrichment of up to 5.6‰, and suggests that sulfate reduction occurred in these anoxic sediments. Increases in total n-alkane concentrations and their specific ratios, such as the Carbon Preference Index (CPI) and Terrestrial Aquatic Ratio (TAR), imply in-lake algal production. Likewise, pigments indicate an up-core increase in total concentration and dominance of cyanobacteria over other phytoplankton.Geochemical trends indicate a recent increase in the lake's trophic state as a result of human-induced changes in the catchment. The study highlights the vulnerability of mountain lakes in the Himalayan region to both natural and anthropogenic processes, and the difficulties associated with reversing trophic state and ecological changes.

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supporting

confidence: 82%

Section: Organic Matter Sourcesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A 100-year record of changes in organic matter characteristics and productivity in Lake Bhimtal in the Kumaon Himalaya, NW India

2012

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Climate Change Impact on Tourism-Based Livelihood and Related Youth Migration—A Case Study for Nainital, Uttarakhand, India

Jasrotia

Sharma

2020

Springer Transactions in Civil and Environmental Engineering

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Trace metals biogeochemistry of Kumaun Himalayan Lakes, Uttarakhand, India

Purushothaman

Chakrapani

2011

Environ Monit Assess

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The increasing urbanization, along with tourism, has posed a major threat to the Kumaun Himalayan Lakes, Uttarakhand, India. The total metal concentration in the water, interstitial water, and sediments along with the metal fractionation studies were carried out to understand the remobilization of the trace metals from the sediments of the lakes. The high concentration of the metals in the water column of the lakes generally decreases with depth and the metals release from the sediment is mainly due to the prevalence of anoxic condition at the sediment-water interface and sediment column. The sediment shows that metals Fe and Cr are derived from detrital source, whereas Co, Ni, and Zn are derived mainly from the organic matter dissolution. The sparse correlation of the trace metals with Ti shows most of the metals have chiefly re-precipitated from the water column. The metals speciation studies also supports that metals experience a high rate of anoxic dissolution and their precipitation onto the sediments are determined by the sediment composition and organic matter content. The high concentration of manganese in the interstitial water in the lakes indicates dissolution of organic matter. The released manganese is adsorbed/precipitated as carbonate phase (Nainital Lake) and oxide pahse (in other lakes). The study shows that the trace metals are regenerated from the sediments due to oxyhydroxide dissolution and organic matter decomposition.

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Biogeochemical records of paleoenvironmental changes in Nainital Lake, Kumaun Himalayas, India

Cited by 27 publications

References 64 publications

A 100-year record of changes in organic matter characteristics and productivity in Lake Bhimtal in the Kumaon Himalaya, NW India

A 100-year record of changes in organic matter characteristics and productivity in Lake Bhimtal in the Kumaon Himalaya, NW India

Climate Change Impact on Tourism-Based Livelihood and Related Youth Migration—A Case Study for Nainital, Uttarakhand, India

Trace metals biogeochemistry of Kumaun Himalayan Lakes, Uttarakhand, India

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