scholarly journals Quantifying the role of moss in terrestrial ecosystem carbon dynamics in northern high-latitudes

2021 ◽  
Author(s):  
Junrong Zha ◽  
Qianlai Zhuang
Keyword(s):  
21St Century ◽  
Land Surface ◽  
Higher Plants ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Carbon Dynamics ◽  
The Arctic ◽  
New Model ◽  
Terrestrial Ecosystem Model ◽  
Rcp 8.5

Abstract. In addition to woody and herbaceous plants, mosses are ubiquitous in northern terrestrial ecosystems, which play an important role in regional carbon, water and energy cycling. Current global land surface models without considering moss may bias the quantification of the regional carbon dynamics. Here we incorporate moss into a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM 5.0), as a new plant functional type to develop a new model (TEM_Moss). The new model explicitly quantifies the interactions between higher plants and mosses and their competition for energy, water, and nutrient. Compared to the estimates using TEM 5.0, the new model estimates that the regional terrestrial soils store 132.7 Pg more C at present day, and will store 157.5 Pg and 179.1 Pg more C under the RCP 8.5 and RCP 2.6 scenarios, respectively, by the end of the 21st century. Ensemble regional simulations forced with different parameters for the 21st century with TEM_Moss predict that the region will accumulate 161.1 ± 142.1 Pg C under the RCP 2.6 scenario, and 186.7 ± 166.1 Pg C under the RCP 8.5 scenario over the century. Our study highlights the necessity of coupling moss into Earth System Models to adequately quantify terrestrial carbon-climate feedbacks in the Arctic.

scholarly journals Quantifying the role of moss in terrestrial ecosystem carbon dynamics in northern high latitudes

2021 ◽  
Vol 18 (23) ◽  
pp. 6245-6269
Author(s):  
Junrong Zha ◽  
Qianlai Zhuang
Keyword(s):  
21St Century ◽  
Land Surface ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Ecosystem Model ◽  
Carbon Dynamics ◽  
The Arctic ◽  
New Model ◽  
Terrestrial Ecosystem Model ◽  
Ecosystem Carbon

Abstract. Mosses are ubiquitous in northern terrestrial ecosystems, and play an important role in regional carbon, water and energy cycling. Current global land surface models that do not consider mosses may bias the quantification of regional carbon dynamics. Here we incorporate mosses as a new plant functional type into the process-based Terrestrial Ecosystem Model (TEM 5.0), to develop a new model (TEM_Moss). The new model explicitly quantifies the interactions between vascular plants and mosses and their competition for energy, water, and nutrients. Compared to the estimates using TEM 5.0, the new model estimates that the regional terrestrial soils currently store 132.7 Pg more C and will store 157.5 and 179.1 Pg more C under the RCP8.5 and RCP2.6 scenarios, respectively, by the end of the 21st century. Ensemble regional simulations forced with different parameters for the 21st century with TEM_Moss predict that the region will accumulate 161.1±142.1 Pg C under the RCP2.6 scenario and 186.7±166.1 Pg C under the RCP8.5 scenario over the century. Our study highlights the necessity of coupling moss into Earth system models to adequately quantify terrestrial carbon–climate feedbacks in the Arctic.

scholarly journals Microbial decomposition processes and vulnerable Arctic soil organic carbon in the 21st century

2018 ◽  
Author(s):  
Junrong Zha ◽  
Qianlai Zhuang
Keyword(s):  
Soil Carbon ◽  
20Th Century ◽  
21St Century ◽  
Carbon Budget ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
The Arctic ◽  
Microbial Decomposition ◽  
Terrestrial Ecosystem Model ◽  
Rcp 8.5

Abstract. Inadequate representation of biogeochemical processes in current biogeochemistry models results in a large uncertainty in carbon budget quantification. Here, detailed microbial mechanisms were incorporated into a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM). Ensemble regional simulations with the model estimated the Arctic ecosystem carbon budget is 76.0 ± 114.8 Pg C during the 20th century, −3.1 ± 61.7 Pg C under the RCP 2.6 scenario and a sink of 94.7 ± 46 Pg C under the RCP 8.5 scenario during the 21st century. Compared to the estimates using a simpler soil decomposition algorithm in TEM, the new model estimated that the Arctic terrestrial ecosystems stored 12 Pg less carbon over the 20th century, 19 Pg C and 30 Pg C less under the RCP 8.5 and RCP 2.6 scenarios, respectively, during the 21st century. When soil carbon within depths 30 cm, 100 cm and 300 cm was considered as initial carbon in the 21st century simulations, the region was estimated to accumulate 65.4, 88.6, and 109.8 Pg C, respectively, under the RCP 8.5 scenario. In contrast, under the RCP 2.6 scenario, the region lost 0.7, 2.2, and 3 Pg C, respectively, to the atmosphere. We conclude that the future regional carbon budget evaluation largely depends on whether or not the adequate microbial activities are represented in earth system models and the sizes of soil carbon considered in model simulations.

scholarly journals Microbial dormancy and its impacts on Arctic terrestrial ecosystem carbon budget

2019 ◽  
Author(s):  
Junrong Zha ◽  
Qianlai Zhuang
Keyword(s):  
Greenhouse Gases ◽  
Carbon Budget ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Carbon Dynamics ◽  
The Arctic ◽  
Earth System ◽  
Ecosystem Carbon ◽  
Rcp 8.5 ◽  
Earth System Models

Abstract. A large amount of soil carbon in the Arctic terrestrial ecosystems could be emitted as greenhouse gases in a warming future. However, lacking detailed microbial processes such as microbial dormancy in current biogeochemistry models might have biased the quantification of the regional carbon dynamics. Here the effect of microbial dormancy was incorporated into a biogeochemistry model to improve the quantification for the last and this century. Compared with the previous model without considering the microbial dormancy, the new model estimated the regional soils stored 75.9 Pg more C in the terrestrial ecosystems during the last century, and will store 50.4 Pg and 125.2 Pg more C under the RCP 8.5 and RCP 2.6 scenarios, respectively, in this century. This study highlights the importance of the representation of microbial dormancy in earth system models to adequately quantify the carbon dynamics in the Arctic.

scholarly journals Microbial decomposition processes and vulnerable arctic soil organic carbon in the 21st century

2018 ◽  
Vol 15 (18) ◽  
pp. 5621-5634 ◽  
Author(s):  
Junrong Zha ◽  
Qianlai Zhuang
Keyword(s):  
Soil Carbon ◽  
20Th Century ◽  
21St Century ◽  
Carbon Budget ◽  
Carbon Sink ◽  
The Arctic ◽  
Microbial Decomposition ◽  
New Model ◽  
Terrestrial Ecosystem Model ◽  
Rcp 8.5

Abstract. Various levels of representations of biogeochemical processes in current biogeochemistry models contribute to a large uncertainty in carbon budget quantification. Here, we present an uncertainty analysis with a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), into which detailed microbial mechanisms were incorporated. Ensemble regional simulations with the new model (MIC-TEM) estimated that the carbon budget of the arctic ecosystems is 76.0±114.8 Pg C during the 20th century, i.e., -3.1±61.7 Pg C under the RCP 2.6 scenario and 94.7±46 Pg C under the RCP 8.5 scenario during the 21st century. Positive values indicate the regional carbon sink while negative values are a source to the atmosphere. Compared to the estimates using a simpler soil decomposition algorithm in TEM, the new model estimated that the arctic terrestrial ecosystems stored 12 Pg less carbon over the 20th century, i.e., 19 and 30 Pg C less under the RCP 8.5 and RCP 2.6 scenarios, respectively, during the 21st century. When soil carbon within depths of 30, 100, and 300 cm was considered as initial carbon in the 21st century simulations, the region was estimated to accumulate 65.4, 88.6, and 109.8 Pg C, respectively, under the RCP 8.5 scenario. In contrast, under the RCP 2.6 scenario, the region lost 0.7, 2.2, and 3 Pg C, respectively, to the atmosphere. We conclude that the future regional carbon budget evaluation largely depends on whether or not adequate microbial activities are represented in earth system models and on the sizes of soil carbon considered in model simulations.

scholarly journals Microbial dormancy and its impacts on northern temperate and boreal terrestrial ecosystem carbon budget

2020 ◽  
Vol 17 (18) ◽  
pp. 4591-4610
Author(s):  
Junrong Zha ◽  
Qianla Zhuang
Keyword(s):  
Greenhouse Gases ◽  
Soil Carbon ◽  
Carbon Budget ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Carbon Dynamics ◽  
Earth System ◽  
New Model ◽  
Ecosystem Carbon ◽  
Earth System Models

Abstract. A large amount of soil carbon in northern temperate and boreal regions could be emitted as greenhouse gases in a warming future. However, lacking detailed microbial processes such as microbial dormancy in current biogeochemistry models might have biased the quantification of the regional carbon dynamics. Here the effect of microbial dormancy was incorporated into a biogeochemistry model to improve the quantification for the last century and this century. Compared with the previous model without considering the microbial dormancy, the new model estimated the regional soils stored 75.9 Pg more C in the terrestrial ecosystems during the last century and will store 50.4 and 125.2 Pg more C under the RCP8.5 and RCP2.6 scenarios, respectively, in this century. This study highlights the importance of the representation of microbial dormancy in earth system models to adequately quantify the carbon dynamics in the northern temperate and boreal natural terrestrial ecosystems.

scholarly journals Freeze/thaw processes in complex permafrost landscapes of northern Siberia simulated using the TEM ecosystem model: impact of thermokarst ponds and lakes

2014 ◽  
Vol 7 (4) ◽  
pp. 1671-1689 ◽  
Author(s):  
S. Yi ◽  
K. Wischnewski ◽  
M. Langer ◽  
S. Muster ◽  
J. Boike
Keyword(s):  
Water Depth ◽  
Land Surface ◽  
Terrestrial Ecosystem ◽  
Climate Scenario ◽  
Water Layer ◽  
Ecosystem Model ◽  
The Arctic ◽  
Thermal Processes ◽  
Freeze Thaw ◽  
Terrestrial Ecosystem Model

Abstract. Freeze/thaw (F/T) processes can be quite different under the various land surface types found in the complex tundra of the Arctic, such as polygonal tundra (wet center and dry rims), ponds, and thermokarst lakes. Proper simulation of these different processes is essential for accurate prediction of the release of greenhouse gases under a warming climate scenario. In this study we have incorporated the water layer into a dynamic organic soil version of the Terrestrial Ecosystem Model (DOS-TEM), having first verified and validated the model. Results showed that (1) the DOS-TEM was very efficient and its results compared well with analytical solutions for idealized cases, and (2) despite a number of limitations and uncertainties in the modeling, the simulations compared reasonably well with in situ measurements from polygon rims, polygon centers (with and without water), and lakes on Samoylov Island, Siberia, indicating the suitability of the DOS-TEM for simulating the various F/T processes. Sensitivity tests were performed on the effects of water depth and our results indicated that both water and snow cover are very important in the simulated thermal processes, for both polygon centers and lakes. We therefore concluded that the polygon rims and polygon centers (with various maximum water depths) should be considered separately, and that the dynamics of water depth in both polygons and lakes should be taken into account when simulating thermal processes for methane emission studies.

scholarly journals Tiling soil textures for terrestrial ecosystem modelling via clustering analysis: a case study with CLASS-CTEM (version 2.1)

2017 ◽  
Author(s):  
Joe R. Melton ◽  
Reinel Sospedra-Alfonso ◽  
Kelly E. McCusker
Keyword(s):  
Soil Texture ◽  
Land Surface ◽  
Clustering Analysis ◽  
Clustering Algorithms ◽  
Terrestrial Ecosystem ◽  
Grid Cell ◽  
Moisture Stress ◽  
Ecosystem Model ◽  
Global Scale ◽  
Terrestrial Ecosystem Model

Abstract. We investigate the application of clustering algorithms to represent sub-grid scale variability in soil texture for use in a global-scale terrestrial ecosystem model. Our model, the coupled Canadian Land Surface Scheme – Canadian Terrestrial Ecosystem Model (CLASS-CTEM), is typically implemented at a coarse spatial resolution (ca. 2.8° × 2.8°) due to its use as the land surface component of the Canadian Earth System Model (CanESM). CLASS-CTEM can, however, be run with tiling of the land surface as a means to represent sub-grid heterogeneity. We first determined that the model was sensitive to tiling of the soil textures via an idealized test case before attempting to cluster soil textures globally. To cluster a high-resolution soil texture dataset onto our coarse model grid, we use two linked algorithms (OPTICS (Ankerst et al., 1999; Daszykowski et al., 2002) and Sander et al. (2003)) to provide tiles of representative soil textures for use as CLASS-CTEM inputs. The clustering process results in, on average, about three tiles per CLASS-CTEM grid cell with most cells having four or less tiles. Results from CLASS-CTEM simulations conducted with the tiled inputs (Cluster) versus those using a simple grid-mean soil texture (Gridmean) show CLASS-CTEM, at least on a global scale, is relatively insensitive to the tiled soil textures, however differences can be large in arid or peatland regions. The Cluster simulation has generally lower soil moisture and lower overall vegetation productivity than the Gridmean simulation except in arid regions where plant productivity increases. In these dry regions, the influence of the tiling is stronger due to the general state of vegetation moisture stress which allows a single tile, whose soil texture retains more plant available water, to yield much higher productivity. Although the use of clustering analysis appears promising as a means to represent sub-grid heterogeneity, soil textures appear to be reasonably represented for global scale simulations using a simple grid-mean value.

scholarly journals ORCHILEAK (revision 3875): a new model branch to simulate carbon transfers along the terrestrial–aquatic continuum of the Amazon basin

2017 ◽  
Vol 10 (10) ◽  
pp. 3821-3859 ◽  
Author(s):  
Ronny Lauerwald ◽  
Pierre Regnier ◽  
Marta Camino-Serrano ◽  
Bertrand Guenet ◽  
Matthieu Guimberteau ◽  
...  
Keyword(s):  
Land Surface ◽  
Water Surface ◽  
Amazon Basin ◽  
River System ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Mean Values ◽  
New Model ◽  
Canopy Soil ◽  
C Cycle

Abstract. Lateral transfer of carbon (C) from terrestrial ecosystems into the inland water network is an important component of the global C cycle, which sustains a large aquatic CO2 evasion flux fuelled by the decomposition of allochthonous C inputs. Globally, estimates of the total C exports through the terrestrial–aquatic interface range from 1.5 to 2.7 Pg C yr−1 (Cole et al., 2007; Battin et al., 2009; Tranvik et al., 2009), i.e. of the order of 2–5 % of the terrestrial NPP. Earth system models (ESMs) of the climate system ignore these lateral transfers of C, and thus likely overestimate the terrestrial C sink. In this study, we present the implementation of fluvial transport of dissolved organic carbon (DOC) and CO2 into ORCHIDEE (Organising Carbon and Hydrology in Dynamic Ecosystems), the land surface scheme of the Institut Pierre-Simon Laplace ESM. This new model branch, called ORCHILEAK, represents DOC production from canopy and soils, DOC and CO2 leaching from soils to streams, DOC decomposition, and CO2 evasion to the atmosphere during its lateral transport in rivers, as well as exchange with the soil carbon and litter stocks on floodplains and in swamps. We parameterized and validated ORCHILEAK for the Amazon basin, the world's largest river system with regard to discharge and one of the most productive ecosystems in the world. With ORCHILEAK, we are able to reproduce observed terrestrial and aquatic fluxes of DOC and CO2 in the Amazon basin, both in terms of mean values and seasonality. In addition, we are able to resolve the spatio-temporal variability in C fluxes along the canopy–soil–water continuum at high resolution (1°, daily) and to quantify the different terrestrial contributions to the aquatic C fluxes. We simulate that more than two-thirds of the Amazon's fluvial DOC export are contributed by the decomposition of submerged litter. Throughfall DOC fluxes from canopy to ground are about as high as the total DOC inputs to inland waters. The latter, however, are mainly sustained by litter decomposition. Decomposition of DOC and submerged plant litter contributes slightly more than half of the CO2 evasion from the water surface, while the remainder is contributed by soil respiration. Total CO2 evasion from the water surface equals about 5 % of the terrestrial NPP. Our results highlight that ORCHILEAK is well suited to simulate carbon transfers along the terrestrial–aquatic continuum of tropical forests. It also opens the perspective that provided parameterization, calibration and validation is performed for other biomes, the new model branch could improve the quantification of the global terrestrial C sink and help better constrain carbon cycle–climate feedbacks in future projections.

scholarly journals A new terrestrial biosphere model with coupled carbon, nitrogen, and phosphorus cycles (QUINCY v1.0; revision 1772)

2019 ◽  
Author(s):  
Tea Thum ◽  
Silvia Caldararu ◽  
Jan Engel ◽  
Melanie Kern ◽  
Marleen Pallandt ◽  
...  
Keyword(s):  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Ecosystem Dynamics ◽  
Soil Conditions ◽  
Monitoring Networks ◽  
Nitrogen And Phosphorus ◽  
Element Cycling ◽  
Terrestrial Biosphere ◽  
Ecosystem Monitoring ◽  
Terrestrial Ecosystem Model

Abstract. The dynamics of terrestrial ecosystems are shaped by the coupled cycles of carbon, nitrogen and phosphorus, and strongly depend on the availability of water and energy. These interactions shape future terrestrial biosphere responses to global change. Many process-based models of the terrestrial biosphere have been gradually extended from considering carbon-water interactions to also including nitrogen, and later, phosphorus dynamics. This evolutionary model development has hindered full integration of these biogeochemical cycles and the feedbacks amongst them. Here we present a new terrestrial ecosystem model QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system), which is formulated around a consistent representation of element cycling in terrestrial ecosystems. This new model includes i) a representation of plant growth which separates source (e.g. photosynthesis) and sink (growth rate of individual tissues, constrained by nutrients, temperature, and water availability) processes; ii) the acclimation of many ecophysiological processes to meteorological conditions and/or nutrient availabilities; iii) an explicit representation of vertical soil processes to separate litter and soil organic matter dynamics; iv) a range of new diagnostics (leaf chlorophyll content; 13C, 14C, and 15N isotope tracers) to allow for a more in-depth model evaluation. We present the model structure and provide an assessment of its performance against a range of observations from global-scale ecosystem monitoring networks. We demonstrate that the framework is capable of consistently simulating ecosystem dynamics across a large gradient in climate and soil conditions, as well as across different plant functional types. To aid this understanding we provide an assessment of the model's sensitivity to its parameterisation and the associated uncertainty.

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