Quantifying the rate and depth dependence of bioturbation based on optically‐stimulated luminescence (OSL) dates and meteoric <sup>10</sup>Be

Johnson, Michelle; Mudd, Simon M.; Pillans, Brad; Spooner, Nigel A.; Fifield, L.K.; Kirkby, M. J.; Gloor, Manuel

doi:10.1002/esp.3520

Cited by 86 publications

(109 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, various groups have attempted to estimate bioturbation rates and incorporate them into landscape models (e.g. Heimsath et al, 2002;Stockmann et al, 2013;Johnson et al, 2014). Previous terrestrial studies argue for an exponential age development down through the soil profile, thought to be the consequence of "diffusion" mixing where sediment is moved randomly in three dimensions.…”

Section: Introductionmentioning

confidence: 99%

Quantification of termite bioturbation in a savannah ecosystem: Application of OSL dating

Kristensen

Thomsen

Murray

et al. 2015

Quaternary Geochronology

View full text Add to dashboard Cite

Luminescence dating is one of the most promising techniques available for studying bioturbation on pedological timescales. In this study, we use multi-grain and single-grain quartz OSL to quantify termite bioturbation processes (Macrotermes natalensis) in a savannah ecosystem in Ghana. Termites transport soil from depth to the surface to construct termitaria. Over time, erosion levels these mounds and returns the sediment to the soil surface. These two processes of construction and erosion together represent an upward "conveyor belt" sediment transport process. We find that the sediment is effectively bleached during the erosion process allowing us to quantify retrospectively, for the first time, the surface deposition rate, the inverse of the upwards transport rate. At this site, this is ~0.28 mm year -1 and began about 4.000 years ago.Downward mixing through subsurface galleries may replace 10-20 % of the volume ka -1 below the unit formed by reburied termite deposits.

show abstract

Section: Introductionmentioning

confidence: 99%

Quantification of termite bioturbation in a savannah ecosystem: Application of OSL dating

Kristensen

Thomsen

Murray

et al. 2015

Quaternary Geochronology

View full text Add to dashboard Cite

show abstract

“…Further modifications to these coefficients could be considered in future work. For example, bioturbation rates may vary with depth (Johnson et al, 2014). There are few explicit measurements of cryoturbation rates, but the available observations suggest that 5 cm 2 year −1 may be a realistic value (Klaminder et al, 2014).…”

Section: Vertical Discretizationmentioning

confidence: 99%

A vertical representation of soil carbon in the JULES land surface scheme (vn4.3_permafrost) with a focus on permafrost regions

2017

View full text Add to dashboard Cite

Abstract. An improved representation of the carbon cycle in permafrost regions will enable more realistic projections of the future climate-carbon system. Currently JULES (the Joint UK Land Environment Simulator) -the land surface model of the UK Earth System Model (UKESM) -uses the standard four-pool RothC soil carbon model. This paper describes a new version of JULES (vn4.3_permafrost) in which the soil vertical dimension is added to the soil carbon model, with a set of four pools in every soil layer. The respiration rate in each soil layer depends on the temperature and moisture conditions in that layer. Cryoturbation/bioturbation processes, which transfer soil carbon between layers, are represented by diffusive mixing. The litter inputs and the soil respiration are both parametrized to decrease with increasing depth. The model now includes a tracer so that selected soil carbon can be labelled and tracked through a simulation. Simulations show an improvement in the large-scale horizontal and vertical distribution of soil carbon over the standard version of JULES (vn4.3). Like the standard version of JULES, the vertically discretized model is still unable to simulate enough soil carbon in the tundra regions. This is in part because JULES underestimates the plant productivity over the tundra, but also because not all of the processes relevant for the accumulation of permafrost carbon, such as peat development, are included in the model. In comparison with the standard model, the vertically discretized model shows a delay in the onset of soil respiration in the spring, resulting in an increased net uptake of carbon during this time. In order to provide a more suitable representation of permafrost carbon for quantifying the permafrost carbon feedback within UKESM, the deep soil carbon in the permafrost region (below 1 m) was initialized using the observed soil carbon. There is now a slight drift in the soil carbon ( < 0.018 % decade −1 ), but the change in simulated soil carbon over the 20th century, when there is little climate change, is comparable to the original vertically discretized model and significantly larger than the drift.

show abstract

“…It is assumed that the mixing intensity will decline with depth due to the decrease in faunal activity with increasing soil depth (Humphreys and Field, 1998;Wilkinson and Humphreys, 2005;Johnson et al, 2014). In the model this takes the form of an exponential relationship:…”

Section: A6 Bioturbationmentioning

confidence: 99%

Insights into biogeochemical cycling from a soil evolution model and long-term chronosequences

2014

View full text Add to dashboard Cite

Abstract. Despite the importance of soil processes for global biogeochemical cycles, our capability for predicting soil evolution over geological timescales is poorly constrained. We attempt to probe our understanding and predictive capability of this evolutionary process by developing a mechanistic soil evolution model, based on an existing model framework, and comparing the predictions with observations from soil chronosequences in Hawaii. Our soil evolution model includes the major processes of pedogenesis: mineral weathering, percolation of rainfall, leaching of solutes, surface erosion, bioturbation, the effects of vegetation in terms of organic matter input and nutrient cycling and can be applied to various bedrock compositions and climates. The specific properties the model simulates over timescales of tens to hundreds of thousand years are, soil depth, vertical profiles of elemental composition, soil solution pH and organic carbon distribution. We demonstrate with this model the significant role that vegetation plays in accelerating the rate of weathering and hence soil profile development. Comparisons with soils that have developed on Hawaiian basalts reveal a remarkably good agreement with Na, Ca and Mg profiles suggesting that the model captures well the key components of soil formation. Nevertheless, differences between modelled and observed K and P are substantial. The fact that these are important plant nutrients suggests that a process likely missing from our model is the active role of vegetation in selectively acquiring nutrients. This study therefore indirectly indicates the valuable role that vegetation can play in accelerating the weathering and thus release of these globally important nutrients into the biosphere.

show abstract

Quantifying the rate and depth dependence of bioturbation based on optically‐stimulated luminescence (OSL) dates and meteoric ¹⁰Be

Cited by 86 publications

References 59 publications

Quantification of termite bioturbation in a savannah ecosystem: Application of OSL dating

Quantification of termite bioturbation in a savannah ecosystem: Application of OSL dating

A vertical representation of soil carbon in the JULES land surface scheme (vn4.3_permafrost) with a focus on permafrost regions

Insights into biogeochemical cycling from a soil evolution model and long-term chronosequences

Contact Info

Product

Resources

About

Quantifying the rate and depth dependence of bioturbation based on optically‐stimulated luminescence (OSL) dates and meteoric 10Be

Cited by 86 publications

References 59 publications

Quantification of termite bioturbation in a savannah ecosystem: Application of OSL dating

Quantification of termite bioturbation in a savannah ecosystem: Application of OSL dating

A vertical representation of soil carbon in the JULES land surface scheme (vn4.3_permafrost) with a focus on permafrost regions

Insights into biogeochemical cycling from a soil evolution model and long-term chronosequences

Contact Info

Product

Resources

About

Quantifying the rate and depth dependence of bioturbation based on optically‐stimulated luminescence (OSL) dates and meteoric ¹⁰Be