Hydrological and climatological controls on radiocarbon concentrations in a tropical stalagmite

Lechleitner, Franziska A.; Baldini, James U.L.; Breitenbach, Sebastian F. M.; Fohlmeister, Jens; McIntyre, Cameron; Goswami, Bedartha; Jamieson, Robert A.; Voort, Tessa Sophia van der; Prufer, Keith M.; Marwan, Norbert; Culleton, Brendan J.; Kennett, Douglas J.; Asmerom, Yemane; Polyak, Victor J.; Eglinton, Timothy I.

doi:10.1016/j.gca.2016.08.039

Cited by 35 publications

(49 citation statements)

References 56 publications

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“…Although all available proxies point to an increase in precipitation or net infiltration after the LGM, M1-5 14 C data do not reflect the processes predicted if the established dependence of calcite dissolution systematics on soil infiltration holds. In contrast to studies from zones more humid when compared to Socotra Island (Genty et al, 2001;Griffiths et al, 2012;Lechleitner et al, 2016;Noronha et al, 2014), the predicted positive feedback of rainfall amount on DCF does not appear to apply here. Instead, increasing rainfall and the respective increase in infiltration seem to go along with a shift to a less closed carbonate dissolution system and an increased forcing towards higher 14 C levels in the soil gas CO 2 by enhanced root respiration compared to a decreasing contribution by CO 2 , which originates from the decomposition of aged SOM.…”

Section: Climatic Controls Of Dcf At Moomi Cavecontrasting

confidence: 99%

Climate-induced speleothem radiocarbon variability on Socotra Island from the Last Glacial Maximum to the Younger Dryas

et al. 2020

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In this study, the dead carbon fraction (DCF) variations in stalagmite M1-5 from Socotra Island in the western Arabian Sea were investigated through a new set of highprecision U-series and radiocarbon ( 14 C) dates. The data reveal an extreme case of very high and also climate-dependent DCF. For M1-5, an average DCF of 56.2 ± 3.4 % is observed between 27 and 18 kyr BP. Such high DCF values indicate a high influence of aged soil organic matter (SOM) and nearly completely closed-system carbonate dissolution conditions. Towards the end of the last glacial period, decreasing Mg/Ca ratios suggest an increase in precipitation which caused a marked change in the soil carbon cycling as indicated by sharply decreasing DCF. This is in contrast to the relation of soil infiltration and DCF as seen in stalagmites from temperate zones.

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Section: Climatic Controls Of Dcf At Moomi Cavecontrasting

confidence: 99%

Climate-induced speleothem radiocarbon variability on Socotra Island from the Last Glacial Maximum to the Younger Dryas

et al. 2020

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“…This is likely due to the input of younger carbon via leaching of dissolved organic carbon. The nonhydromorphic Luvisols are marked by an enrichment of clay in the deeper soil, which can enhance carbon stabilization (Lutzow et al, 2006). This is also reflected in the turnover time of the 60-80 cm layer in the Othmarsingen Luvisol; in this clayenriched depth interval (Walthert et al, 2003), turnover time is relatively high as compared to the other (colder) nonhydromorphic soils (Fig.…”

Section: Carbon Dynamics Reflect Soil-specific Characteristics At Depthmentioning

confidence: 91%

Dynamics of deep soil carbon – insights from <sup>14</sup>C time series across a climatic gradient

et al. 2019

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Quantitative constraints on soil organic matter (SOM) dynamics are essential for comprehensive understanding of the terrestrial carbon cycle. Deep soil carbon is of particular interest as it represents large stocks and its turnover times remain highly uncertain. In this study, SOM dynamics in both the top and deep soil across a climatic (average temperature ∼ 1-9 • C) gradient are determined using time-series (∼ 20 years) 14 C data from bulk soil and waterextractable organic carbon (WEOC). Analytical measurements reveal enrichment of bomb-derived radiocarbon in the deep soil layers on the bulk level during the last 2 decades. The WEOC pool is strongly enriched in bomb-derived carbon, indicating that it is a dynamic pool. Turnover time estimates of both the bulk and WEOC pool show that the latter cycles up to a magnitude faster than the former. The presence of bomb-derived carbon in the deep soil, as well as the rapidly turning WEOC pool across the climatic gradient, implies that there likely is a dynamic component of carbon in the deep soil. Precipitation and bedrock type appear to exert a stronger influence on soil C turnover time and stocks as compared to temperature.

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“…Variations in δ 13 C at this cave site have previously been attributed to variations in rainfall registered above the cave, governed by the seasonal migration of the ITCZ89. Therefore, δ 13 C at Yok Balum Cave is a more sensitive proxy to variations in regional rainfall amount (and particularly drying) than δ 18 O, which is a mixed signal including precipitation amount, moisture source, and storm path length910. Yok Balum Cave is located at the northernmost extent of the boreal summer ITCZ, a remarkably sensitive location to record even small shifts in ITCZ position9.…”

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confidence: 83%

Tropical rainfall over the last two millennia: evidence for a low-latitude hydrologic seesaw

Lechleitner

Breitenbach

Rehfeld

et al. 2017

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The presence of a low- to mid-latitude interhemispheric hydrologic seesaw is apparent over orbital and glacial-interglacial timescales, but its existence over the most recent past remains unclear. Here we investigate, based on climate proxy reconstructions from both hemispheres, the inter-hemispherical phasing of the Intertropical Convergence Zone (ITCZ) and the low- to mid-latitude teleconnections in the Northern Hemisphere over the past 2000 years. A clear feature is a persistent southward shift of the ITCZ during the Little Ice Age until the beginning of the 19th Century. Strong covariation between our new composite ITCZ-stack and North Atlantic Oscillation (NAO) records reveals a tight coupling between these two synoptic weather and climate phenomena over decadal-to-centennial timescales. This relationship becomes most apparent when comparing two precisely dated, high-resolution paleorainfall records from Belize and Scotland, indicating that the low- to mid-latitude teleconnection was also active over annual-decadal timescales. It is likely a combination of external forcing, i.e., solar and volcanic, and internal feedbacks, that drives the synchronous ITCZ and NAO shifts via energy flux perturbations in the tropics.

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Hydrological and climatological controls on radiocarbon concentrations in a tropical stalagmite

Cited by 35 publications

References 56 publications

Climate-induced speleothem radiocarbon variability on Socotra Island from the Last Glacial Maximum to the Younger Dryas

Climate-induced speleothem radiocarbon variability on Socotra Island from the Last Glacial Maximum to the Younger Dryas

Dynamics of deep soil carbon – insights from <sup>14</sup>C time series across a climatic gradient

Tropical rainfall over the last two millennia: evidence for a low-latitude hydrologic seesaw

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Hydrological and climatological controls on radiocarbon concentrations in a tropical stalagmite

Cited by 35 publications

References 56 publications

Climate-induced speleothem radiocarbon variability on Socotra Island from the Last Glacial Maximum to the Younger Dryas

Climate-induced speleothem radiocarbon variability on Socotra Island from the Last Glacial Maximum to the Younger Dryas

Dynamics of deep soil carbon – insights from &lt;sup&gt;14&lt;/sup&gt;C time series across a climatic gradient

Tropical rainfall over the last two millennia: evidence for a low-latitude hydrologic seesaw

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Dynamics of deep soil carbon – insights from <sup>14</sup>C time series across a climatic gradient