Lateral carbon export from polygonal tundra catchments on Samoylov Island, Lena River Delta

2020 ◽  
Author(s):  
Lutz Beckebanze ◽  
Josefine Walz ◽  
Benjamin R.K. Runkle ◽  
David Holl ◽  
Irina V. Fedorova Fedorova ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Time Scales ◽  
Carbon Flux ◽  
Carbon Balance ◽  
Dissolved Inorganic Carbon ◽  
Growing Season ◽  
Carbon Fluxes ◽  
Carbon Export ◽  
Lena River ◽  
Annual Time

<p>Permafrost-affected soils contain a large quantity of soil organic carbon (SOC). Two processes control the amount of carbon stored in soils. The photosynthetic activity of plants produces biomass that may accumulate in the soil, while microorganism’s respiration leads to a depletion of the soil carbon stocks through decomposition. The carbon balance defines whether a soil acts as a source or sink of carbon. In recent decades, many researchers observed and analyzed the carbon balance of permafrost soils. In most cases, the focus lays on observations of the vertical carbon flux (CO<sub>2</sub> and CH<sub>4</sub>) to estimate the carbon balance. However, there is lack of information regarding the lateral losses of carbon via dissolved organic carbon (DOC) or dissolved inorganic carbon (DIC) in ground- or rainwater.</p><p>In this study, we estimate the lateral carbon fluxes from a permafrost-affected site in north-eastern Siberia, Russia. Long-term measurements of vertical carbon fluxes have been conducted at this study site. By considering both, the vertical and the lateral carbon fluxes, we estimate the complete carbon balance for one growing season in 2014 and discuss the contribution of the lateral carbon flux to the overall carbon balance.</p><p>The results show that the vertical CO<sub>2</sub> fluxes dominate the carbon balance during the growing season from June 8<sup>th</sup> – September 8<sup>th</sup> (-19 ± 1.2 kg-C m<sup>-2</sup>). The lateral fluxes of DOC and DIC reached values of +0.1 ± 0.01 and +1.4 ± 0.09 kg-C m<sup>-2</sup>, respectively, whereas the vertical fluxes of CH<sub>4</sub> had values of +0.7 ± 0.02 kg-C m<sup>-2 </sup>integrated over this time. By considering the lateral carbon export, the net ecosystem carbon balance of the study area was reduced by 8%. On shorter time scales of days, the relationship between lateral and vertical flux changes within the growing season. Early in the growing season, the lateral carbon flux outpaces the weak vertical CO<sub>2</sub> uptake for a few days and converts the estimated carbon balance from a sink to a source.</p><p>We conclude that lateral carbon fluxes have a larger influence on the carbon balance of our study site on time scales of days (early and late growing season) and that this influence decreases with annual time scales. Therefore, the vertical carbon flux can be seen as a good approximation for the carbon balance of this study site on annual time scales.</p>

scholarly journals Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

2008 ◽  
Vol 12 (2) ◽  
pp. 625-634 ◽  
Author(s):  
R. R. Pawson ◽  
D. R. Lord ◽  
M. G. Evans ◽  
T. E. H. Allott
Keyword(s):  
Organic Carbon ◽  
Carbon Flux ◽  
Relative Importance ◽  
Carbon Export ◽  
Event Scale ◽  
Organic Carbon Flux ◽  
Poc Export ◽  
Event Based ◽  
First Time ◽  
Annual Flux

Abstract. This study investigates for the first time the relative importance of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the fluvial carbon flux from an actively eroding peatland catchment in the southern Pennines, UK. Event scale variability in DOC and POC was examined and the annual flux of fluvial organic carbon was estimated for the catchment. At the event scale, both DOC and POC were found to increase with discharge, with event based POC export accounting for 95% of flux in only 8% of the time. On an annual cycle, exports of 35.14 t organic carbon (OC) are estimated from the catchment, which represents an areal value of 92.47 g C m−2 a−1. POC was the most significant form of organic carbon export, accounting for 80% of the estimated flux. This suggests that more research is required on both the fate of POC and the rates of POC export in eroding peatland catchments.

scholarly journals The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

2019 ◽  
Vol 16 (2) ◽  
pp. 485-503 ◽  
Author(s):  
Tim Rixen ◽  
Birgit Gaye ◽  
Kay-Christian Emeis ◽  
Venkitasubramani Ramaswamy
Keyword(s):  
Indian Ocean ◽  
Organic Carbon ◽  
Spatial Variability ◽  
Primary Production ◽  
Carbon Flux ◽  
Carbon Fluxes ◽  
Matter Content ◽  
Organic Carbon Flux ◽  
The Indian Ocean ◽  
Organic Carbon Fluxes

Abstract. Data obtained from long-term sediment trap experiments in the Indian Ocean in conjunction with satellite observations illustrate the influence of primary production and the ballast effect on organic carbon flux into the deep sea. They suggest that primary production is the main control on the spatial variability of organic carbon fluxes at most of our study sites in the Indian Ocean, except at sites influenced by river discharges. At these sites the spatial variability of organic carbon flux is influenced by lithogenic matter content. To quantify the impact of lithogenic matter on the organic carbon flux, the densities of the main ballast minerals, their flux rates and seawater properties were used to calculate sinking speeds of material intercepted by sediment traps. Sinking speeds in combination with satellite-derived export production rates allowed us to compute organic carbon fluxes. Flux calculations imply that lithogenic matter ballast increases organic carbon fluxes at all sampling sites in the Indian Ocean by enhancing sinking speeds and reducing the time of organic matter respiration in the water column. We calculated that lithogenic matter content in aggregates and pellets enhances organic carbon flux rates on average by 45 % and by up to 62 % at trap locations in the river-influenced regions of the Indian Ocean. Such a strong lithogenic matter ballast effect explains the fact that organic carbon fluxes are higher in the low-productive southern Java Sea compared to the high-productive western Arabian Sea. It also implies that land use changes and the associated enhanced transport of lithogenic matter from land into the ocean may significantly affect the CO2 uptake of the organic carbon pump in the receiving ocean areas.

scholarly journals Climate data induced uncertainties in simulated carbon fluxes under corn and soybean systems

2020 ◽  
Author(s):  
Varaprasad Bandaru
Keyword(s):  
Carbon Flux ◽  
Carbon Balance ◽  
Management Practices ◽  
Irrigation Management ◽  
Carbon Fluxes ◽  
Climate Data ◽  
Weather Variables ◽  
Relative Significance ◽  
Daily Weather ◽  
The U.S

Abstract. Net carbon balance on croplands depends on numerous factors (e.g., crop type, soil, climate and management practices) and their interactions. Agroecosystem models are generally used to assess cropland carbon fluxes under various agricultural land use and land management practices because of their ability to capture the complex interactive effects of factors influencing carbon balance. For regional carbon flux simulations, generally gridded climate data sets are used because they offer data for each grid cell of the region of interest. However, studies consistently report large uncertainties in gridded climate datasets, which will affect the accuracy of carbon flux simulations. This study investigates the uncertainties in daily weather variables of commonly used high resolution gridded climate datasets in the U.S (NARR, NLDAS, Prism and Daymet), and their impact on the accuracy of simulated Net Ecosystem Exchange (NEE) under irrigated and non-irrigated corn and soybeans using the Environmental Policy Integrated Climate (EPIC) agroecosystem model and observational data at four flux tower cropland sites in the U.S Midwest region. Further, the relative significance of each weather variable in influencing the uncertainty in flux estimates was evaluated. Results suggest that daily weather variables in all gridded climate datasets display some degree of bias, leading to considerable uncertainty in simulated NEE fluxes. The gridded climate datasets produced based on interpolation techniques (i.e. Daymet and Prism) were shown to have less uncertainties, and resulted in NEE estimates with relatively higher accuracy, likely due to their higher spatial resolution and higher dependency on meteorological station observations. The Mean Absolute Percentage Errors (MAPE) values of average growing season NEE estimates for Dayment, Prism, NLDAS and NARR include 22.53 %, 23.45 %, 62.52 % and 66.18 %, respectively. The NEE under irrigation management (MAPE = 53.15 %) tends to be more sensitive to uncertainties compared to the fluxes under non-irrigation (MAPE = 34.19 %). Further, this study highlights that NEE fluxes respond differently to the individual climate variables, and responses vary with management practices. Under irrigation management, NEE fluxes are more sensitive to shortwave radiation and temperature. Conversely, under non-irrigation management, precipitation is the most dominant climate factor influencing uncertainty in simulated NEE fluxes. These findings demonstrate that careful consideration is necessary when selecting climate data to mitigate uncertainties in simulated NEE fluxes. Further, alternative approaches such as integration of remote sensing data products may help reduce the models' dependency on climate datasets and improve the accuracy in the simulated CO2 fluxes.

scholarly journals Transport of organic carbon from the Mogot Experimental Watershed in the southern mountainous taiga of eastern Siberia

2006 ◽  
Vol 37 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Kazuyoshi Suzuki ◽  
Eiichi Konohira ◽  
Yusuke Yamazaki ◽  
Jumpei Kubota ◽  
Tetsuo Ohata ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Flux ◽  
Eastern Siberia ◽  
Snowmelt Runoff ◽  
Amur River ◽  
Lena River ◽  
Organic Carbon Flux ◽  
Doc Concentration ◽  
Thawing Depth ◽  
Annual Transport

More than 60% of river runoff from the Lena River basin originates in the southern mountainous region of eastern Siberia within the permafrost zone. We studied the transport of dissolved organic carbon (DOC) and particulate organic carbon (POC) within the Mogot Experimental Watershed, which is close to the drainage divide between the Lena and Amur River basins in the southern mountainous taiga region, from 1 August 2000 to 12 November 2001. DOC concentration was strongly related to thawing depth at the bottom of the main valley when thawing depth was less than 20 cm during snowmelt runoff. When thawing depth was equal to or greater than 20 cm, DOC concentration was more closely related to the rate of river discharge in summer runoff. On the basis of our observations, we extrapolated the annual transport of DOC and POC to be 4.75 g C m−2 yr−1 and 0.03 C kg C m−2 yr−1, respectively. Transport of organic carbon from the catchment was about 4.78 g C m−2 yr−1 during 2001. DOC is the main form of organic carbon flux in the study area.

scholarly journals Are small mountainous tropical watersheds of oceanic islands important for carbon export?

2012 ◽  
Vol 9 (6) ◽  
pp. 7117-7163 ◽  
Author(s):  
E. Lloret ◽  
C. Dessert ◽  
E. Lajeunesse ◽  
O. Crispi ◽  
L. Pastor ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Level ◽  
Carbon Fluxes ◽  
Oceanic Islands ◽  
Carbon Export ◽  
Extreme Floods ◽  
Dissolved Carbon ◽  
Small Watersheds ◽  
Tropical Watersheds ◽  
Global Carbon

Abstract. In the tropic, the small watersheds are affected by intense meteorological events playing an important role on the erosion of soils and therefore on the associated organic carbon fluxes. We studied the geochemistry of three small watersheds around the Basse-Terre volcanic Island (FWI) during a four years period, by measuring DOC, POC and DIC concentrations. The mean annual yields ranged 8.1–15.8 t C km−2 yr−1, 1.9–8.6 t C km−2 yr−1 and 8.1–25.5 t C km−2 yr−1 for DIC, DOC and POC, respectively. Floods and extreme floods represent 45 to 70 % of the annual DOC flux, and more than 80 % of the annual POC flux. The DIC flux occurs essentially during the low water level, only 43 % of the annual DIC flux is exported during floods. The distribution of the dissolved carbon between the inorganic and the organic fraction is correlated to the hydrodynamic of rivers. During low water level and floods, the dissolved carbon is exported under the inorganic form (DIC/DOC = 2.6 ± 2.1), while during extreme floods, the dissolved carbon transported is mostly organic (DIC/DOC = 0.7 ± 0.2). The residence time of the organic carbon in Guadeloupean soils may vary from 381 to 1000 yr, and is linked to the intensity of meteorological events than the frequency of meteorological events. Looking at the global carbon mass balance, the total export of organic carbon coming from small tropical and volcanic mountainous rivers is estimated about 2.0–8.9 Tg C yr−1 for DOC and about 8.4–26.5 Tg C yr−1 for POC, emphasizing that these carbon fluxes are significant and should be included in global carbon budgets.

scholarly journals Process-based analysis of terrestrial carbon flux predictability

2021 ◽  
Author(s):  
István Dunkl ◽  
Aaron Spring ◽  
Pierre Friedlingstein ◽  
Victor Brovkin
Keyword(s):  
Soil Moisture ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Cycle ◽  
Air Temperature ◽  
Carbon Flux ◽  
Carbon Fluxes ◽  
Ecosystem Processes ◽  
Terrestrial Carbon ◽  
Ensemble Simulations

Abstract. Despite efforts to decrease the discrepancy between simulated and observed terrestrial carbon fluxes, the uncertainty in trends and patterns of the land carbon fluxes remains high. This difficulty raises the question to what extent the terrestrial carbon cycle is predictable, and which processes explain the predictability. Here, the perfect model approach is used to assess the potential predictability of net primary production (NPPpred) and heterotrophic respiration (Rhpred) by using ensemble simulations conducted with the Max-Planck-Institute Earth System Model. In order to asses the role of local carbon flux predictability (CFpred) on the predictability of the global carbon cycle, we suggest a new predictability metric weighted by the amplitude of the flux anomalies. Regression analysis is used to determine the contribution of the predictability of different environmental drivers to NPPpred and Rhpred (soil moisture, air temperature and radiation for NPP and soil organic carbon, air temperature and precipitation for Rh). NPPpred is driven to 62 and 30 % by the predictability of soil moisture and temperature, respectively. Rhpred is driven to 52 and 27 % by the predictability of soil organic carbon temperature, respectively. The decomposition of predictability shows that the relatively high Rhpred compared to NPPpred is due to the generally high predictability of soil organic carbon. The seasonality in NPPpred and Rhpred patterns can be explained by the change in limiting factors over the wet and dry months. Consequently, CFpred is controlled by the predictability of the currently limiting environmental factor. Differences in CFpred between ensemble simulations can be attributed to the occurrence of wet and dry years, which influences the predictability of soil moisture and temperature. This variability of predictability is caused by the state dependency of ecosystem processes. Our results reveal the crucial regions and ecosystem processes to be considered when initializing a carbon prediction system.

Process-based analysis of land carbon flux predictability

2021 ◽  
Author(s):  
István Dunkl ◽  
Aaron Spring ◽  
Victor Brovkin
Keyword(s):  
Soil Moisture ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Interannual Variability ◽  
Carbon Flux ◽  
Carbon Fluxes ◽  
Ecosystem Processes ◽  
Environmental Drivers ◽  
Terrestrial Carbon ◽  
State Dependency

<p>The land-atmosphere CO<sub>2</sub> exchange exhibits a very high interannual variability which dominates variability in atmospheric CO<sub>2</sub> concentration. Despite efforts to decrease the discrepancy between simulated and observed terrestrial carbon fluxes, the uncertainty in trends and patterns of the land carbon fluxes remains high. This difficulty raises the question to what extent the terrestrial carbon cycle is even predictable, and which processes explain the predictability. In this study, the perfect model approach is used to assess the potential predictability of net primary production (NPP) and heterotrophic respiration (Rh) by using initialized ensemble experiments simulated with the Max Planck Institute Earth System Model. In order to determine which processes are causing the derived predictability patterns, carbon flux predictability was decomposed into individual drivers. Regression analysis was used to determine the contribution of the predictability of different environmental drivers to the predictability of NPP and Rh (Soil moisture, temperature and radiation for NPP and soil organic carbon, temperature and precipitation for Rh). The main drivers of NPP predictability are soil moisture and temperature, while the predictability signal from radiation is lost after the first month of simulation. Rh predictability is predominantly driven by soil organic carbon, temperature and locally by precipitation. This decomposition of predictability shows that the relatively high Rh predictability is due to the generally high predictability of soil organic carbon. The assessed seasonality in predictability patterns can be explained by the change in limiting factors of NPP and Rh over the wet and dry months. This leads to the adjustment of carbon flux predictability to the predictability of the currently limiting environmental factor. Differences in the predictability between initializations can be attributed to the interannual variability in soil moisture and temperature predictability. This variability is caused by the state dependency of nonlinear ecosystem processes. These results reveal the crucial regions and ecosystem processes to be considered when initializing a carbon prediction system.</p>

scholarly journals Analyzing the causes and spatial pattern of the European 2003 carbon flux anomaly using seven models

2008 ◽  
Vol 5 (2) ◽  
pp. 561-583 ◽  
Author(s):  
M. Vetter ◽  
G. Churkina ◽  
M. Jung ◽  
M. Reichstein ◽  
S. Zaehle ◽  
...  
Keyword(s):  
Central Europe ◽  
Carbon Flux ◽  
Ecosystem Respiration ◽  
Growing Season ◽  
Carbon Fluxes ◽  
Ecosystem Processes ◽  
Total Carbon ◽  
Reference Period ◽  
Process Oriented ◽  
One Year

Abstract. Globally, the year 2003 is associated with one of the largest atmospheric CO2 rises on record. In the same year, Europe experienced an anomalously strong flux of CO2 from the land to the atmosphere associated with an exceptionally dry and hot summer in Western and Central Europe. In this study we analyze the magnitude of this carbon flux anomaly and key driving ecosystem processes using simulations of seven terrestrial ecosystem models of different complexity and types (process-oriented and diagnostic). We address the following questions: (1) how large were deviations in the net European carbon flux in 2003 relative to a short-term baseline (1998–2002) and to longer-term variations in annual fluxes (1980 to 2005), (2) which European regions exhibited the largest changes in carbon fluxes during the growing season 2003, and (3) which ecosystem processes controlled the carbon balance anomaly . In most models the prominence of 2003 anomaly in carbon fluxes declined with lengthening of the reference period from one year to 16 years. The 2003 anomaly for annual net carbon fluxes ranged between 0.35 and –0.63 Pg C for a reference period of one year and between 0.17 and –0.37 Pg C for a reference period of 16 years for the whole Europe. In Western and Central Europe, the anomaly in simulated net ecosystem productivity (NEP) over the growing season in 2003 was outside the 1σ variance bound of the carbon flux anomalies for 1980–2005 in all models. The estimated anomaly in net carbon flux ranged between –42 and –158 Tg C for Western Europe and between 24 and –129 Tg C for Central Europe depending on the model used. All models responded to a dipole pattern of the climate anomaly in 2003. In Western and Central Europe NEP was reduced due to heat and drought. In contrast, lower than normal temperatures and higher air humidity decreased NEP over Northeastern Europe. While models agree on the sign of changes in simulated NEP and gross primary productivity in 2003 over Western and Central Europe, models diverge in the estimates of anomalies in ecosystem respiration. Except for two process models which simulate respiration increase, most models simulated a decrease in ecosystem respiration in 2003. The diagnostic models showed a weaker decrease in ecosystem respiration than the process-oriented models. Based on the multi-model simulations we estimated the total carbon flux anomaly over the 2003 growing season in Europe to range between –0.02 and –0.27 Pg C relative to the net carbon flux in 1998–2002.

scholarly journals Robotic observations of high wintertime carbon export in California coastal waters

2016 ◽  
Vol 13 (10) ◽  
pp. 3109-3129 ◽  
Author(s):  
James K. B. Bishop ◽  
Michael B. Fong ◽  
Todd J. Wood
Keyword(s):  
Surface Waters ◽  
Coastal Waters ◽  
Carbon Flux ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
High Surface ◽  
Carbon Export ◽  
Santa Barbara ◽  
San Pedro ◽  
Mesopelagic Zone

Abstract. Biologically mediated particulate organic and inorganic carbon (POC and PIC) export from surface waters is the principal determinant of the vertical oceanic distribution of pH and dissolved inorganic carbon and thus sets the conditions for air–sea exchange of CO2; exported organic matter also provides the energy fueling communities in the mesopelagic zone. However, observations are temporally and spatially sparse. Here we report the first hourly-resolved optically quantified POC and PIC sedimentation rate time series from an autonomous Lagrangian Carbon Flux Explorer (CFE), which monitored particle flux using an imaging optical sedimentation recorder (OSR) at depths below 140 m in the Santa Cruz Basin, CA, in May 2012, and in January and March 2013. Highest POC vertical flux ( ∼  100–240 mmol C m−2 d−1) occurred in January, when most settling material was millimeter- to centimeter-sized aggregates but when surface biomass was low; fluxes were  ∼  18 and  ∼  6 mmol C m−2 d−1, respectively, in March and May, under high surface biomass conditions. An unexpected discovery was that January 2013 fluxes measured by CFE were 20 times higher than that measured by simultaneously deployed surface-tethered OSR; multiple lines of evidence indicate strong undersampling of aggregates larger than 1 mm in the latter case. Furthermore, the January 2013 CFE fluxes were about 10 times higher than observed during multiyear sediment trap observations in the nearby Santa Barbara and San Pedro basins. The strength of carbon export in biologically dynamic California coastal waters is likely underestimated by at least a factor of 3 and at times by a factor of 20.

Sign in / Sign up

Export Citation Format

Share Document