@article{MishraPrasadMarwanetal.2017,
  author    = {Mishra, Praveen Kumar and Prasad, Sushma and Marwan, Norbert and Anoop, A. and Krishnan, R. and Gaye, Birgit and Basavaiah, N. and Stebich, Martina and Menzel, Philip and Riedel, Nils},
  title     = {Contrasting pattern of hydrological changes during the past two millennia from central and northern India},
  series = {Global and planetary change},
  volume    = {161},
  journal   = {Global and planetary change},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0921-8181},
  doi       = {10.1016/j.gloplacha.2017.12.005},
  pages     = {97 -- 107},
  year      = {2017},
  abstract  = {High resolution reconstructions of the India Summer Monsoon (ISM) are essential to identify regionally different patterns of climate change and refine predictive models. We find opposing trends of hydrological proxies between northern (Sahiya cave stalagmite) and central India (Lonar Lake) between 100 and 1300 CE with the strongest anti-correlation between 810 and 1300 CE. The apparently contradictory data raise the question if these are related to widely different regional precipitation patterns or reflect human influence in/around the Lonar Lake. By comparing multiproxy data with historical records, we demonstrate that only the organic proxies in the Lonar Lake show evidence of anthropogenic impact. However, evaporite data (mineralogy and delta O-18) are indicative of precipitation/evaporation (P/E) into the Lonar Lake. Back-trajectories of air-mass circulation over northern and central India show that the relative contribution of the Bay of Bengal (BoB) branch of the ISM is crucial for determining the delta O-18 of carbonate proxies only in north India, whereas central India is affected significantly by the Arabian Sea (AS) branch of the ISM. We conclude that the delta O-18 of evaporative carbonates in the Lonar Lake reflects P/E and, in the interval under consideration, is not influenced by source water changes. The opposing trend between central and northern India can be explained by (i) persistent multidecadal droughts over central India between 810 and 1300 CE that provided an effective mechanism for strengthening sub-tropical westerly winds resulting in enhancement of wintertime (non-monsoonal) rainfall over northern parts of the Indian subcontinent, and/or (ii) increased moisture influx to northern India from the depleted BoB source waters.},
  language  = {en}
}
@article{MishraPrasadJehangiretal.2018,
  author    = {Mishra, Praveen Kumar and Prasad, Sushma and Jehangir, Arshid and Anoop, Ambili and Yousuf, Abdul R. and Gaye, Birgit},
  title     = {Investigating the role of meltwater versus precipitation seasonality in abrupt lake-level rise in the high-altitude Tso Moriri Lake (India)},
  series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences},
  volume    = {493},
  journal   = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0031-0182},
  doi       = {10.1016/j.palaeo.2017.12.026},
  pages     = {20 -- 29},
  year      = {2018},
  abstract  = {We present late Quaternary lake level reconstruction from the high altitude Tso Moriri Lake (NW Indian Himalaya) using a combination of new and published data from shallow and deep water cores, and catchment geomorphology. Our reconstruction indicates two dramatic lake level increases - a late glacial (ca. 16.4-12.6 cal kyr B.P.) rise of 65 m, and a 47 m rise during the early Holocene wet phase (ca. 11.2-8.5 cal kyr B.P.) which are separated by the Younger Dryas (YD) event. We decouple the role of precipitation seasonality and snow melt using a combination of proxies sensitive to the Indian Summer Monsoon (ISM), and a regional spatio-temporal transect that provides information on the eastward penetration of the winter westerlies. A comparison of shallow and deep water cores shows that (i) the first lake level increase (similar to 65 m, ca. 16.4-12.6 cal kyr B.P.) is caused by melt water inflow triggered by the increasing summer insolation; (ii) the second lake level increase (similar to 47 m, 11.2-8.5 cal kyr B.P.) is largely caused by a rise in annual precipitation coupled with reduced summer evaporation; (iii) in contrast to the onset of ISM (Bay of Bengal branch) at ca. 14.7 ka in lower elevations in NE India, the hydroclimatic influence of ISM in the high altitude Himalaya is seen only between 12.7 and 12 cal kyr B.P., though the influence of solar insolation (via increased snowmelt) is visible from 16.4 cal kyr B.P. onwards; (iv) the eastward penetration of westerlies in Indian Himalayas is strongly influenced by the strength of the Siberian High.},
  language  = {en}
}
@article{PrasadMishraMenzeletal.2016,
  author    = {Prasad, Sushma and Mishra, Praveen Kumar and Menzel, Philip and Gaye, Birgit and Jehangir, Arshid and Yousuf, Abdul R.},
  title     = {Testing the validity of productivity proxy indicators in high altitude Tso Moriri Lake, NW Himalaya (India)},
  series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences},
  volume    = {449},
  journal   = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0031-0182},
  doi       = {10.1016/j.palaeo.2016.02.027},
  pages     = {421 -- 430},
  year      = {2016},
  abstract  = {We use multiple proxies (delta C-13(org), delta N-15(org), C/N, amino acids, biogenic silica) from the catchment, lake surface and core sediments to (i) identify the factors influencing conventional lacustrine primary productivity (LPP) indicators (isotopic covariance, C/N) in the sediments from the pristine high altitude Tso Moriri Lake during the late Quaternary, (ii) compare C/N and bulk organic isotopic data from the core with available biogenic silica and amino acid data to test the applicability of conventional LPP indicators during the late Quaternary, and (iii) evaluate the degree of sensitivity of LPP to climate change. Our results show that climate driven changes in water salinity and source water changes have influenced the isotopic (delta C-13, delta N-15) content of the lake water and hence the isotopic composition of bulk organic matter. Erosion has also played a role in masking the LPP as the catchment sediments from this high altitude lake have low C/N thereby casting doubt on the effectiveness of this parameter as an LPP indicator. Independent LPP indicators in Tso Moriri sediments clearly indicate that it is driven by climate change and increases during warmer periods. However, our data show that the LPP in recent times is not much higher than during the early Holocene, ruling out any impact of recent warming on LPP and therefore the possibility of large carbon sequestration in high altitude oligotrophic lakes. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{MishraPrasadAnoopetal.2015,
  author    = {Mishra, Praveen Kumar and Prasad, Sushma and Anoop, A. and Plessen, Birgit and Jehangir, Arshid and Gaye, Birgit and Menzel, Philip and Weise, Stephan M. and Yousuf, Abdul R.},
  title     = {Carbonate isotopes from high altitude Tso Moriri Lake (NW Himalayas) provide clues to late glacial and Holocene moisture source and atmospheric circulation changes},
  series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences},
  volume    = {425},
  journal   = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0031-0182},
  doi       = {10.1016/j.palaeo.2015.02.031},
  pages     = {76 -- 83},
  year      = {2015},
  abstract  = {High resolution isotopic (delta O-18 and delta C-13) investigations on endogenic carbonates (calcite/aragonite) from Tso Moriri Lake, NW Himalaya show dramatic fluctuations during the late glacial and the early Holocene, and a persistent enrichment trend during the late Holocene. Changes in this lake are largely governed by the [input (meltwater + monsoon precipitation)/evaporationj (WE) ratio, also reflected in changes in the carbonate mineralogy with aragonite being formed during periods of lowest I/E. Using new isotopic data on endogenic carbonates in combination with the available data on geochemistry, mineralogy, and reconstructed mean annual precipitation, we demonstrate that the late glacial and early Holocene carbonate delta O-18 variability resulted from fluctuating Indian summer monsoon (ISM) precipitation in NW Himalaya. This region experienced increasing ISM precipitation between ca. 13.1 and 11.7 cal ka and highest ISM precipitation during the early Holocene (11.2-8.5 cal ka). However, during the late Holocene, evaporation was the dominant control on the carbonate delta O-18. Regional comparison of reconstructed hydrological changes from Tso Moriri Lake with other archives from the Asian summer monsoon and westerlies domain shows that the intensified westerly influence that resulted in higher lake levels (after 8 cal ka) in central Asia was not strongly felt in NW Himalaya. (C) 2015 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{RiedelStebichAnoopetal.2015,
  author    = {Riedel, Nils and Stebich, Martina and Anoop, Ambili and Basavaiah, Nathani and Menzel, Philip and Prasad, Sushma and Sachse, Dirk and Sarkar, Saswati and Wiesner, Martin},
  title     = {Modern pollen vegetation relationships in a dry deciduous monsoon forest: A case study from Lonar Crater Lake, central India},
  series = {Quaternary international : the journal of the International Union for Quaternary Research},
  volume    = {371},
  journal   = {Quaternary international : the journal of the International Union for Quaternary Research},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1040-6182},
  doi       = {10.1016/j.quaint.2015.01.046},
  pages     = {268 -- 279},
  year      = {2015},
  abstract  = {As part of ongoing research on Holocene lacustrine sediments of Lonar Crater Lake (central India), pollen assemblages in lake surface sediment and soil samples were studied to unravel pollenevegetation relationships, including pollen transport processes in tropical dry deciduous forest vegetation. Furthermore, palynological results were compared with geochemical proxies and spatial features of the lake sediments and the vegetation. The obtained data reveal strong differences in pollen assemblages and pollen concentrations between and within the studied trapping media. Local arboreal vegetation is adequately represented in the soil samples, but is less represented in the lake surface sediment samples. The composition of the lacustrine pollen assemblages is mainly influenced by patterns of transport through surface and channel runoff. Besides the relevance of our new data for reliable interpretation of fossil pollen spectra extracted from Lonar sediment cores, the results of this study are of general importance for the understanding of Quaternary pollen assemblages from tropical lacustrine archives, as well as for the implementation and selection of suitable approaches for quantitative pollen based environmental reconstructions in south Asia and beyond. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.},
  language  = {en}
}
@article{MishraAnoopSchettleretal.2015,
  author    = {Mishra, Praveen Kumar and Anoop, Ambili and Schettler, Georg and Prasad, Sushma and Jehangir, Arshid and Menzel, Peter and Naumann, Rudolf and Yousuf, A. R. and Basavaiah, Nathani and Deenadayalan, Kannan and Wiesner, Martin G. and Gaye, Birgit},
  title     = {Reconstructed late Quaternary hydrological changes from Lake Tso Moriri, NW Himalaya},
  series = {Quaternary international : the journal of the International Union for Quaternary Research},
  volume    = {371},
  journal   = {Quaternary international : the journal of the International Union for Quaternary Research},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1040-6182},
  doi       = {10.1016/j.quaint.2014.11.040},
  pages     = {76 -- 86},
  year      = {2015},
  abstract  = {We present the results of our investigations on the radiocarbon dated core sediments from the Lake Tso Moriri, NW Himalaya aimed at reconstructing palaeohydrological changes in this climatically sensitive region. Based on the detailed geochemical, mineralogical and sedimentological analysis, we recognise several short-term fluctuations superimposed upon seven major palaeohydrological stages identified in this lake since similar to 26 cal ka. Stage I (>20.2 cal ka): shallow lake characterised by input of coarse-grained detrital sediments; Stage II (20.2-16.4 cal ka): lake deepening and intensification of this trend ca. 18 cal ka; Stage III (16.4-11.2 cal ka): rising lake levels with a short term wet phase (13.1-11.7 cal ka); Stage IV (11.2-8.5 cal ka): early Holocene hydrological maxima and highest lake levels inferred to have resulted from early Holocene Indian monsoon intensification, as records from central Asia indicate weaker westerlies during this interval; Stage V (8.5-5.5 cal ka): mid-Holocene climate deterioration; Stage VI (5.5-2.7 cal ka): progressive lowering of lake level; Stage VII (2.7-0 cal ka): onset of modern conditions. The reconstructed hydrological variability in Lake Tso Moriri is governed by temperature changes (meltwater inflow) and monsoon precipitation (increased runoff). A regional comparison shows considerable differences with other palaeorecords from peninsular India during late Holocene. (C) 2014 Elsevier Ltd and INQUA. All rights reserved.},
  language  = {en}
}
@article{MenzelAnupamaBasavaiahetal.2015,
  author    = {Menzel, Philip and Anupama, Krishnamurthy and Basavaiah, Nathani and Das, Brijraj Krishna and Gaye, Birgit and Herrmann, Nicole and Prasad, Sushma},
  title     = {The use of amino acid analyses in (palaeo-) limnological investigations: A comparative study of four Indian lakes in different climate regimes},
  series = {Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society},
  volume    = {160},
  journal   = {Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0016-7037},
  doi       = {10.1016/j.gca.2015.03.028},
  pages     = {25 -- 37},
  year      = {2015},
  abstract  = {In the present study, we report the results of comprehensive amino acid (AA) analyses of four Indian lakes from different climate regimes. We focus on the investigation of sediment cores retrieved from the lakes but data of modern sediment as well as vascular plant, soil, and suspended particulate matter samples from individual lakes are also presented. Commonly used degradation and organic matter source indices are tested for their applicability to the lake sediments, and we discuss potential reasons for possible limitations. A principal component analysis including the monomeric AA composition of organic matter of all analysed samples indicates that differences in organic matter sources and the environmental properties of the individual lakes are responsible for the major variability in monomeric AA distribution of the different samples. However, the PCA also gives a factor that most probably separates the samples according to their state of organic matter degradation. Using the factor loadings of the individual AA monomers, we calculate a lake sediment degradation index (LI) that might be applicable to other palaeo-lake investigations. (C) 2015 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{SarkarPrasadWilkesetal.2015,
  author    = {Sarkar, Saswati and Prasad, Sushma and Wilkes, Heinz and Riedel, Nils and Stebich, Martina and Basavaiah, Nathani and Sachse, Dirk},
  title     = {Monsoon source shifts during the drying mid-Holocene: Biomarker isotope based evidence from the core 'monsoon zone' (CMZ) of India},
  series = {Quaternary science reviews : the international multidisciplinary research and review journal},
  volume    = {123},
  journal   = {Quaternary science reviews : the international multidisciplinary research and review journal},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0277-3791},
  doi       = {10.1016/j.quascirev.2015.06.020},
  pages     = {144 -- 157},
  year      = {2015},
  abstract  = {A better understanding of past variations of the Indian Summer Monsoon (ISM), that plays a vital role for the still largely agro-based economy in India, can lead to a better assessment of its potential impact under global climate change scenarios. However, our knowledge of spatiotemporal patterns of ISM strength is limited due to the lack of high-resolution, continental paleohydrological records. Here, we reconstruct centennial-scale hydrological variability during the Holocene associated to changes in the intensity of the ISM based on a record of lipid biomarker abundances and compound-specific stable isotopic composition of a 10 m long sediment core from saline alkaline Lonar Lake, situated in the core 'monsoon zone' of central India. We identified three main periods of distinct hydrology during the Holocene in central India. The period between 10.1 and 6 cal ka BP was likely the wettest during the Holocene. Lower average chain length (ACL) index values (29.4-28.6) and negative delta C-13(wax) values (-34.8 parts per thousand to -27.8 parts per thousand) of leaf wax n-alkanes indicate the dominance of woody C-3 vegetation in the catchment, and negative delta D-wax values (concentration weighted average) (-171 parts per thousand to -147 parts per thousand) suggest a wet period due to an intensified monsoon. After 6 cal ka BP, a gradual shift to less negative delta C-13(wax) values (particularly for the grass derived n-C-31) and appearance of the triterpene lipid tetrahymanol, generally considered as a marker for salinity and water column stratification, mark the onset of drier conditions. At 5.1 cal ka BP an increasing flux of leaf wax n-alkanes along with the highest flux of tetrahymanol indicate a major lowering of the lake level. Between 4.8 and 4 cal ka BP, we find evidence for a transition to arid conditions, indicated by high and strongly variable tetrahymanol flux. In addition, a pronounced shift to less negative delta C-13(wax) values, in particular for n-C-31 (-25.2 parts per thousand to -22.8 parts per thousand), during this period indicates a change of dominant vegetation to C-4 grasses. In agreement with other proxy data, such as deposition of evaporite minerals, we interpret this period to reflect the driest conditions in the region during the last 10.1 ka. This transition led to protracted late Holocene arid conditions after 4 ka with the presence of a permanent saline lake, supported by the sustained presence of tetrahymanol and more positive average delta D-wax values (-122 parts per thousand to -141 parts per thousand). A late Holocene peak of cyanobacterial biomarker input at 1.3 cal ka BP might represent an event of lake eutrophication, possibly due to human impact and the onset of cattle/livestock farming in the catchment. A unique feature of our record is the presence of a distinct transitional period between 4.8 and 4 cal ka BP, which was characterized by some of the most negative delta D-wax values during the Holocene (up to -180 parts per thousand), when all other proxy data indicate the driest conditions during the Holocene. These negative delta D-wax values can as such most reasonably be explained by a shift in moisture source area and/or pathways or rainfall seasonality during this transitional period. We hypothesize that orbital induced weakening of the summer solar insolation and associated reorganization of the general atmospheric circulation, as a possible southward displacement of the tropical rainbelt, led to an unstable hydroclimate in central India between 4.8 and 4 ka.},
  language  = {en}
}
@article{SarkarWilkesPrasadetal.2014,
  author    = {Sarkar, Saswati and Wilkes, Heinz and Prasad, Sushma and Brauer, Achim and Riedel, Nils and Stebich, Martina and Basavaiah, Nathani and Sachse, Dirk},
  title     = {Spatial heterogeneity in lipid biomarker distributions in the catchment and sediments of a crater lake in central India},
  series = {Organic geochemistry : the international journal for rapid publication of current research in organic geochemistry and biochemistry},
  volume    = {66},
  journal   = {Organic geochemistry : the international journal for rapid publication of current research in organic geochemistry and biochemistry},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0146-6380},
  doi       = {10.1016/j.orggeochem.2013.11.009},
  pages     = {125 -- 136},
  year      = {2014},
  abstract  = {The basin-scale spatial variability in lipid biomarker proxies in lacustrine sediments, which are established tools for studying continental environmental change, has rarely been examined. It is often implicitly assumed that a lake sediment core provides an average integral of catchment sources. Here we evaluated the distribution of lipid biomarkers in a modern ecosystem and compared it with the sedimentary record. We analyzed lipid biomarkers in terrestrial and aquatic organisms and in lake surface sediments from 17 locations within the saline-alkaline Lonar crater lake in central India. Terrestrial vegetation and lake surface sediments were characterized by relatively high average chain length (ACL) index values (29.6-32.8) of leaf wax n-alkanes, consistent with suggestions that plants in drier and warmer climates produce longer chain alkyl lipids than plants in cooler and humid areas. A heterogeneous spatial distribution of ACL values in lake surface sediments was found: at locations away from the shore, the values were highest (31 or more), possibly indicating different sources and/or transport of terrestrial biomarkers. In floating, benthic microbial mats and surface sediment, n-heptadecane, carotenoids, diploptene, phytol and tetrahymanol occurred in large amounts. Interestingly, these biomarkers of a unique bacterial community were found in substantially higher concentrations in nearshore sediment samples. We suggest that human influence and subsequent nutrient supply resulted in increased primary productivity, leading to an unusually high concentration of tetrahymanol in the nearshore sediments. In summary, the data showed that substantial heterogeneity existed within the lake, but leaf wax n-alkanes in a core from the center of the lake represented an integral of catchment conditions. However, lake level fluctuation may potentially affect aquatic lipid biomarker distributions in lacustrine sediments, in addition to source changes.},
  language  = {en}
}
@article{BasavaiahWiesnerAnoopetal.2014,
  author    = {Basavaiah, Nathani and Wiesner, M. G. and Anoop, Ambili and Menzel, P. and Nowaczyk, Norbert R. and Deenadayalan, K. and Brauer, Achim and Gaye, Birgit and Naumann, R. and Riedel, N. and Stebich, M. and Prasad, Sushma},
  title     = {Physicochemical analyses of surface sediments from the Lonar Lake, central India - implications for palaeoenvironmental reconstruction},
  series = {Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology},
  volume    = {184},
  journal   = {Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology},
  number    = {1},
  publisher = {Schweizerbart},
  address   = {Stuttgart},
  issn      = {1863-9135},
  doi       = {10.1127/1863-9135/2014/0515},
  pages     = {51 -- 68},
  year      = {2014},
  abstract  = {We report the results of our investigations on the catchment area, surface sediments, and hydrology of the monsoonal Lonar Lake, central India. Our results indicate that the lake is currently stratified with an anoxic bottom layer, and there is a spatial heterogeneity in the sensitivity of sediment parameters to different environmental processes. In the shallow (0-5 m) near shore oxic-suboxic environments the lithogenic and terrestrial organic content is high and spatially variable, and the organics show degradation in the oxic part. Due to aerial exposure resulting from lake level changes of at least 3m, the evaporitic carbonates are not completely preserved. In the deep water (>5 m) anoxic environment the lithogenics are uniformly distributed and the delta C-13 is an indicator not only for aquatic vs. terrestrial plants but also of lake pH and salinity. The isotopic composition of the evaporites is dependent not only on the isotopic composition of source water (monsoon rainfall and stream inflow) and evaporation, but is also influenced by proximity to the isotopically depleted stream inflow. We conclude that in the deep water environment lithogenic content, and isotopic composition of organic matter can be used for palaeoenvironmental reconstruction.},
  language  = {en}
}