Simulating loss of primary silicate minerals from soil due to long-term weathering using Allogen: Comparison with soil chronosequence, lake sediment and river solute flux data

The Paleoecologic recod provides unique insights into the response of communities to environmental perturbations of different duration and intensity. Climate is a primary agent of environmental change and its long-term effect on the vegetation of the Yellowstone/Grand Teton region is revealed in a network of pollen records (Whitlock, 1993). Fire frequency is controlled by climate, and as climate changes so too does the importance of fire in shaping spatial patterns of vegetation. The prehistoric record of Yellowstone's Northern Range, for example, shows the response of vegetation to the absence of major fires in the last 150 years (Whitlock et al., 1991; Engstrom et al., 1991). In longer records spanning the last 14,000 years, periods of frequent fire are suggested by sediments containing high percentages of fire-adapted trees, including lodgepole pine and Douglas-fir, and high amounts of charcoal (Bamosky et al., 1987; Millspaugh and Whitlock, 1993; Whitlock, 1993). The primary research objective has been to study the vegetational history of Yellowstone and its sensitivity to hanges in climate and fire frequency. This information is necessary to understand better the relative effects of climate, natural disturbance, and human perturbation on the Yellowstone landscape. Fossil pollen and plant macrofossils from dated-lake sediment cores provide information on past vegetation and climate. The frequency of charcoal particles and other fire indicators in dated lake-sediment cores offer evidence of past fires.

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Gap-filling strategies for annual VOC flux data sets

Biogeosciences ◽

10.5194/bg-11-2429-2014 ◽

2014 ◽

Vol 11 (8) ◽

pp. 2429-2442 ◽

Cited By ~ 10

Author(s):

I. Bamberger ◽

L. Hörtnagl ◽

M. Walser ◽

A. Hansel ◽

G. Wohlfahrt

Keyword(s):

Linear Interpolation ◽

Winter Period ◽

Data Sets ◽

Gap Filling ◽

Data Set ◽

Mountain Meadow ◽

Flux Data ◽

Flux Measurements ◽

Annual Patterns

Abstract. Up to now the limited knowledge about the exchange of volatile organic compounds (VOCs) between the biosphere and the atmosphere is one of the factors which hinders more accurate climate predictions. Complete long-term flux data sets of several VOCs to quantify the annual exchange and validate recent VOC models are basically not available. In combination with long-term VOC flux measurements the application of gap-filling routines is inevitable in order to replace missing data and make an important step towards a better understanding of the VOC ecosystem–atmosphere exchange on longer timescales. We performed VOC flux measurements above a mountain meadow in Austria during two complete growing seasons (from snowmelt in spring to snow reestablishment in late autumn) and used this data set to test the performance of four different gap-filling routines, mean diurnal variation (MDV), mean gliding window (MGW), look-up tables (LUT) and linear interpolation (LIP), in terms of their ability to replace missing flux data in order to obtain reliable VOC sums. According to our findings the MDV routine was outstanding with regard to the minimization of the gap-filling error for both years and all quantified VOCs. The other gap-filling routines, which performed gap-filling on 24 h average values, introduced considerably larger uncertainties. The error which was introduced by the application of the different filling routines increased linearly with the number of data gaps. Although average VOC fluxes measured during the winter period (complete snow coverage) were close to zero, these were highly variable and the filling of the winter period resulted in considerably higher uncertainties compared to the application of gap-filling during the measurement period. The annual patterns of the overall cumulative fluxes for the quantified VOCs showed a completely different behaviour in 2009, which was an exceptional year due to the occurrence of a severe hailstorm, compared to 2011. Methanol was the compound which, at 381.5 mg C m−2 and 449.9 mg C m−2, contributed most to the cumulative VOC carbon emissions in 2009 and 2011, respectively. In contrast to methanol emissions, however, considerable amounts of monoterpenes (−327.3 mg C m−2) were deposited onto the mountain meadow during 2009 caused by a hailstorm. Other quantified VOCs had considerably lower influences on the annual patterns.

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Modeling the Carbon Cycle of a Subtropical Chinese Fir Plantation Using a Multi-Source Data Fusion Approach

Forests ◽

10.3390/f11040369 ◽

2020 ◽

Vol 11 (4) ◽

pp. 369

Author(s):

Longwei Hu ◽

Honglin He ◽

Yan Shen ◽

Xiaoli Ren ◽

Shao-kui Yan ◽

...

Keyword(s):

Data Fusion ◽

Terrestrial Ecosystem ◽

Chinese Fir ◽

Model Parameters ◽

Ecosystem Models ◽

Flux Data ◽

Source Data ◽

Simulation Results ◽

Chinese Fir Plantation

Process-based terrestrial ecosystem models are increasingly being used to predict carbon (C) cycling in forest ecosystems. Given the complexity of ecosystems, these models inevitably have certain deficiencies, and thus the model parameters and simulations can be highly uncertain. Through long-term direct observation of ecosystems, numerous different types of data have accumulated, providing valuable opportunities to determine which sources of data can most effectively reduce the uncertainty of simulation results, and thereby improve simulation accuracy. In this study, based on a long-term series of observations (biometric and flux data) of a subtropical Chinese fir plantation ecosystem, we use a model–data fusion framework to evaluate the effects of different constrained data on the parameter estimation and uncertainty of related variables, and systematically evaluate the uncertainty of parameters. We found that plant C pool observational data contributed to significant reductions in the uncertainty of parameter estimates and simulation, as these data provide information on C pool size. However, none of the data effectively constrained the foliage C pool, indicating that this pool should be a target for future observational activities. The assimilation of soil organic C observations was found to be important for reducing the uncertainty or bias in soil C pools. The key findings of this study are that the assimilation of multiple time scales and types of data stream are critical for model constraint and that the most accurate simulation results are obtained when all available biometric and flux data are used as constraints. Accordingly, our results highlight the importance of using multi-source data when seeking to constrain process-based terrestrial ecosystem models.

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Mineralogical impact on organic nitrogen across a long-term soil chronosequence (0.3–4100kyr)

Geochimica et Cosmochimica Acta ◽

10.1016/j.gca.2010.01.006 ◽

2010 ◽

Vol 74 (7) ◽

pp. 2142-2164 ◽

Cited By ~ 36

Author(s):

Robert Mikutta ◽

Klaus Kaiser ◽

Nicole Dörr ◽

Antje Vollmer ◽

Oliver A. Chadwick ◽

...

Keyword(s):

Organic Nitrogen ◽

Soil Chronosequence

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Towards a history of Holocene P dynamics for the Northern Hemisphere using lake sediment geochemical records

10.5194/egusphere-egu21-14897 ◽

2021 ◽

Author(s):

Madeleine Moyle ◽

John Boyle ◽

Richard Chiverrell

Keyword(s):

Human Impact ◽

Lake Sediment ◽

Northern Hemisphere ◽

Human Activity ◽

Lake Water ◽

Process Model ◽

P Cycling ◽

History Of ◽

P Supply

Present day phosphorus (P) enrichment and accelerated P cycling are changes superimposed on a dynamic Holocene history of landscape recovery from glaciation, changes in climate, and long-term low-intensity human activity. Knowledge of the changing role of human activity in driving long-term P dynamics is essential for understanding landscape P export and managing both terrestrial and aquatic environments.Here we apply a simple process model to published lake sediment geochemical P records from 24 sites distributed across the Northern Hemisphere, producing Holocene records of landscape P yield and reconstructions of lake water TP concentrations. These records are a first attempt to produce values for average P export for the Northern Hemisphere over the Holocene, which can be used for constraining long-term landscape P cycling models.Individual site trajectories of reconstructed Holocene landscape P yield and lake water TP varied systematically, with differences attributable to landscape development history, in turn driven by climate, human impact and other local factors. Three distinct traits are apparent across the records. Mountain sites with minimal direct human impact show falling Holocene P supply, and conform to conceptual models of natural soil development (Trait 1). Lowland sites&#160; where substantial (pre-)historic agriculture was present show progressively increasing Holocene P supply (Trait 2). Lowland sites may also show a rapid acceleration in P supply over the last few centuries, where high intensity land use, including settlements and farming, are present (Trait 3).This long-term perspective is pivotal to understanding drivers of change in coupled terrestrial and aquatic P cycling. Our reconstructions of long-term lake water TP are particularly useful for target-driven management of aquatic systems.

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Supplementary material to "Cosmogenic nuclide and solute flux data from central Cuba emphasize the importance of both physical and chemical denudation in highly weathered landscapes"

10.5194/gchron-2021-31-supplement ◽

2021 ◽

Author(s):

Mae Kate Campbell ◽

Paul R. Bierman ◽

Amanda H. Schmidt ◽

Rita Sibello Hernández ◽

Alejandro García-Moya ◽

...

Keyword(s):

Solute Flux ◽

Flux Data ◽

Cosmogenic Nuclide ◽

Supplementary Material ◽

Physical And Chemical

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Comparing lake sediment records of landscape macronutrient loadings with N14CP model simulations: 200 years of change in British lakes

10.5194/egusphere-egu2020-9968 ◽

2020 ◽

Author(s):

John Boyle ◽

Ed Tipping ◽

Jess Davies ◽

Neil Rose ◽

Simon Turner ◽

...

Keyword(s):

Lake Sediment ◽

Large Scale ◽

Process Models ◽

Mountain Lake ◽

Scale Model ◽

Data Sets ◽

Empirical Reality ◽

C Isotopes ◽

Sediment Records

To fully understand coupling between P and other macronutrients it is necessary to have both long-term data sets and process models, combining empirical reality with numerical simulation of coupling processes. Here, lake sediment records of N and P from four UK lakes are compared with model output from N14CP, a long-term, large-scale model of cycling and export of macronutrients from the landscape. The sediment records at the three lakes that have substantial lowland contributions reveal strongly increasing N and P loading through the late 19th century, with steady increases through the twentieth century. Corresponding changes in N and C isotopes are observed. However, the one mountain lake show maximum N and P loadings in the 19th century, with declines through the twentieth, consistent with a wholly different land use history. The N14CP model shows N and P increasing from mid 19th century for average lowland sites, in agreement with the lowland sediment records. The implications of these results for our knowledge about the history of P and N coupling and leaching from UK soils are discussed.

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