scholarly journals The CO<sub>2</sub> exchange of biological soil crusts in a semiarid grass-shrubland at the northern transition zone of the Negev desert, Israel

2008 ◽  
Vol 5 (3) ◽  
pp. 1969-2001 ◽  
Author(s):  
B. Wilske ◽  
J. Burgheimer ◽  
A. Karnieli ◽  
E. Zaady ◽  
M. O. Andreae ◽  
...  
Keyword(s):  
Biological Soil Crusts ◽  
Negev Desert ◽  
Co2 Uptake ◽  
Co2 Efflux ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Soil Crusts ◽  
Dew Formation ◽  
Rain Season ◽  
Winter Rain

Abstract. Biological soil crusts (BSC) contribute significantly to the soil surface cover in many dryland ecosystems. A mixed type of BSC, which consists of cyanobacteria, mosses and cyanolichens, constitutes more than 60% of ground cover in the semiarid grass-shrub steppe at Sayeret Shaked in the northern Negev Desert, Israel. This study aimed at parameterizing the carbon sink capacity of well-developed BSC in undisturbed steppe systems. Mobile enclosures on permanent soil borne collars were used to investigate BSC-related CO2 fluxes in situ and with natural moisture supply during 10 two-day field campaigns within seven months from fall 2001 to summer 2002. Highest BSC-related CO2 deposition between −11.31 and −17.56 mmol m−2 per 15 h was found with BSC activated from rain and dew during the peak of the winter rain season. Net CO2 deposition by BSC was calculated to compensate 120%, −26%, and less than 3% of the concurrent soil CO2 efflux from November–January, February–May and November–May, respectively. Thus, BSC effectively compensated soil CO2 effluxes when CO2 uptake by vascular vegetation was probably at its low point. Nighttime respiratory emission reduced daily BSC-related CO2 deposition within the period November–January by 11–123% and on average by 27%. The analysis of CO2 fluxes and water inputs from the various sources showed that the bulk of BSC-related CO2 deposition occurs during periods with frequent rain events and subsequent condensation from water accumulated in the upper soil layers. Significant BSC activity on days without detectable atmospheric water supply emphasized the importance of high soil moisture contents as additional water source for soil-dwelling BSC, whereas activity upon dew formation at low soil water contents was not of major importance for BSC-related CO2 deposition. However, dew may still be important in attaining a pre-activated status during the transition from a long "summer" anabiosis towards the first winter rain.

scholarly journals The CO<sub>2</sub> exchange of biological soil crusts in a semiarid grass-shrubland at the northern transition zone of the Negev desert, Israel

2008 ◽  
Vol 5 (5) ◽  
pp. 1411-1423 ◽  
Author(s):  
B. Wilske ◽  
J. Burgheimer ◽  
A. Karnieli ◽  
E. Zaady ◽  
M. O. Andreae ◽  
...  
Keyword(s):  
Biological Soil Crusts ◽  
Negev Desert ◽  
Co2 Uptake ◽  
Co2 Efflux ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Soil Crusts ◽  
Dew Formation ◽  
Rain Season ◽  
Winter Rain

Abstract. Biological soil crusts (BSC) contribute significantly to the soil surface cover in many dryland ecosystems. A mixed type of BSC, which consists of cyanobacteria, mosses and cyanolichens, constitutes more than 60% of ground cover in the semiarid grass-shrub steppe at Sayeret Shaked in the northern Negev Desert, Israel. This study aimed at parameterizing the carbon sink capacity of well-developed BSC in undisturbed steppe systems. Mobile enclosures on permanent soil borne collars were used to investigate BSC-related CO2 fluxes in situ and with natural moisture supply during 10 two-day field campaigns within seven months from fall 2001 to summer 2002. Highest BSC-related CO2 deposition between –11.31 and –17.56 mmol m−2 per 15 h was found with BSC activated from rain and dew during the peak of the winter rain season. Net CO2 deposition by BSC was calculated to compensate 120%, –26%, and less than 3% of the concurrent soil CO2 efflux from November–January, February–May and November–May, respectively. Thus, BSC effectively compensated soil CO2 effluxes when CO2 uptake by vascular vegetation was probably at its low point. Nighttime respiratory emission reduced daily BSC-related CO2 deposition within the period November–January by 11–123% and on average by 27%. The analysis of CO2 fluxes and water inputs from the various sources showed that the bulk of BSC-related CO2 deposition occurs during periods with frequent rain events and subsequent condensation from water accumulated in the upper soil layers. Significant BSC activity on days without detectable atmospheric water supply emphasized the importance of high soil moisture contents as additional water source for soil-dwelling BSC, whereas activity upon dew formation at low soil water contents was not of major importance for BSC-related CO2 deposition. However, dew may still be important in attaining a pre-activated status during the transition from a long "summer" anabiosis towards the first winter rain.

scholarly journals Hot-Moments of Soil CO2 Efflux in a Water-Limited Grassland

Soil Systems ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 47 ◽  
Author(s):  
Rodrigo Vargas ◽  
Enrique Sánchez-Cañete P. ◽  
Penélope Serrano-Ortiz ◽  
Jorge Curiel Yuste ◽  
Francisco Domingo ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Temporal Variability ◽  
Empirical Models ◽  
Soil Co2 Efflux ◽  
Wavelet Coherence ◽  
Support Vector ◽  
Co2 Efflux ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Precipitation Pulses

The metabolic activity of water-limited ecosystems is strongly linked to the timing and magnitude of precipitation pulses that can trigger disproportionately high (i.e., hot-moments) ecosystem CO2 fluxes. We analyzed over 2-years of continuous measurements of soil CO2 efflux (Fs) under vegetation (Fsveg) and at bare soil (Fsbare) in a water-limited grassland. The continuous wavelet transform was used to: (a) describe the temporal variability of Fs; (b) test the performance of empirical models ranging in complexity; and (c) identify hot-moments of Fs. We used partial wavelet coherence (PWC) analysis to test the temporal correlation between Fs with temperature and soil moisture. The PWC analysis provided evidence that soil moisture overshadows the influence of soil temperature for Fs in this water limited ecosystem. Precipitation pulses triggered hot-moments that increased Fsveg (up to 9000%) and Fsbare (up to 17,000%) with respect to pre-pulse rates. Highly parameterized empirical models (using support vector machine (SVM) or an 8-day moving window) are good approaches for representing the daily temporal variability of Fs, but SVM is a promising approach to represent high temporal variability of Fs (i.e., hourly estimates). Our results have implications for the representation of hot-moments of ecosystem CO2 fluxes in these globally distributed ecosystems.

Cyanobacterial Diversity in Biological Soil Crusts along a Precipitation Gradient, Northwest Negev Desert, Israel

2014 ◽  
Vol 70 (1) ◽  
pp. 219-230 ◽  
Author(s):  
Martin Hagemann ◽  
Manja Henneberg ◽  
Vincent J. M. N. L. Felde ◽  
Sylvie L. Drahorad ◽  
Simon M. Berkowicz ◽  
...  
Keyword(s):  
Biological Soil Crusts ◽  
Negev Desert ◽  
Precipitation Gradient ◽  
Soil Crusts ◽  
Cyanobacterial Diversity

scholarly journals Exploring the "overflow tap" theory: linking forest soil CO<sub>2</sub> fluxes and individual mycorrhizosphere components to photosynthesis

2012 ◽  
Vol 9 (1) ◽  
pp. 79-95 ◽  
Author(s):  
A. Heinemeyer ◽  
M. Wilkinson ◽  
R. Vargas ◽  
J.-A. Subke ◽  
E. Casella ◽  
...  
Keyword(s):  
Strong Relationship ◽  
C Sequestration ◽  
Data Availability ◽  
Wavelet Coherence ◽  
Co2 Efflux ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Soil System ◽  
Environmental Responses ◽  
Wavelet Coherence Analysis

Abstract. Quantifying soil organic carbon stocks (SOC) and their dynamics accurately is crucial for better predictions of climate change feedbacks within the atmosphere-vegetation-soil system. However, the components, environmental responses and controls of the soil CO2 efflux (Rs) are still unclear and limited by field data availability. The objectives of this study were (1) to quantify the contribution of the various Rs components, specifically its mycorrhizal component, (2) to determine their temporal variability, and (3) to establish their environmental responses and dependence on gross primary productivity (GPP). In a temperate deciduous oak forest in south east England hourly soil and ecosystem CO2 fluxes over four years were measured using automated soil chambers and eddy covariance techniques. Mesh-bag and steel collar soil chamber treatments prevented root or both root and mycorrhizal hyphal in-growth, respectively, to allow separation of heterotrophic (Rh) and autotrophic (Ra) soil CO2 fluxes and the Ra components, roots (Rr) and mycorrhizal hyphae (Rm). Annual cumulative Rs values were very similar between years (740 ± 43 g C m−2 yr−1) with an average flux of 2.0 ± 0.3 μmol CO2 m−2 s−1, but Rs components varied. On average, annual Rr, Rm and Rh fluxes contributed 38, 18 and 44%, respectively, showing a large Ra contribution (56%) with a considerable Rm component varying seasonally. Soil temperature largely explained the daily variation of Rs (R2 = 0.81), mostly because of strong responses by Rh (R2 = 0.65) and less so for Rr (R2 = 0.41) and Rm (R2 = 0.18). Time series analysis revealed strong daily periodicities for Rs and Rr, whilst Rm was dominated by seasonal (~150 days), and Rh by annual periodicities. Wavelet coherence analysis revealed that Rr and Rm were related to short-term (daily) GPP changes, but for Rm there was a strong relationship with GPP over much longer (weekly to monthly) periods and notably during periods of low Rr. The need to include individual Rs components in C flux models is discussed, in particular, the need to represent the linkage between GPP and Ra components, in addition to temperature responses for each component. The potential consequences of these findings for understanding the limitations for long-term forest C sequestration are highlighted, as GPP via root-derived C including Rm seems to function as a C "overflow tap", with implications on the turnover of SOC.

Snail Mucus Increases the CO2 Efflux of Biological Soil Crusts

Ecosystems ◽  
2021 ◽  
Author(s):  
S. Rinehart ◽  
N. D. Shamir Weller ◽  
D. Hawlena
Keyword(s):  
Biological Soil Crusts ◽  
Co2 Efflux ◽  
Soil Crusts

scholarly journals Cyanobacterial populations in biological soil crusts of the northwest Negev Desert, Israel – effects of local conditions and disturbance

2016 ◽  
pp. fiw228 ◽  
Author(s):  
Martin Hagemann ◽  
Manja Henneberg ◽  
Vincent J. M. N. L. Felde ◽  
Simon M. Berkowicz ◽  
Hagai Raanan ◽  
...  
Keyword(s):  
Biological Soil Crusts ◽  
Negev Desert ◽  
Local Conditions ◽  
Soil Crusts

scholarly journals Modeling the variability in annual carbon fluxes related to biological soil crusts in a Mediterranean shrubland

2009 ◽  
Vol 6 (4) ◽  
pp. 7295-7324 ◽  
Author(s):  
B. Wilske ◽  
J. Burgheimer ◽  
K. Maseyk ◽  
A. Karnieli ◽  
E. Zaady ◽  
...  
Keyword(s):  
Carbon Deposition ◽  
Terrestrial Ecosystem ◽  
Biological Soil Crusts ◽  
Monitoring Site ◽  
Co2 Fluxes ◽  
Ecosystem Monitoring ◽  
Area Index ◽  
Soil Crusts ◽  
Mediterranean Shrubland ◽  
Annual Carbon

Abstract. Biological soil crusts (BSC) constitute a spatially prominent part of the photosynthesizing vegetation in many dryland ecosystems. This study assesses the annual net carbon deposition related to BSC growth in a Mediterranean shrubland for the years 2001–2003 using a model developed to account for the nature of hydration in the poikilohydric life trait of the BSC. Data for BSC-related net CO2 fluxes were obtained from in-situ measurements at the International Long-term Ecological Research site Sayeret Shaked (ILTER-SSK) in the northern Negev Desert, Israel. The BSC was smooth to rugose, up to 15 mm thick and consisted mainly of mosses, cyanobacteria and cyano-lichens. In order to obtain annual estimates, BSC-related CO2 fluxes were correlated with climate records provided by the meteorological station of the Terrestrial Ecosystem Monitoring Site network (TEMS) adjacent to SSK. The annual carbon deposition related to BSC growth was assessed from (1) an overall mean of net CO2 flux multiplied with annual activity periods of BSC based on precipitation records, and (2) from a simple precipitation-driven activity model (PdAM). This model combines an algorithm, previously developed to model gas exchange processes in vascular plants, with an empirical module that switches the algorithm on as soon as water is available to maintain activity of poikilohydric BSC. Based on a constant BSC area index of 0.6 m2 m−2 at ILTER-SSK, the final model suggests a large inter-annual variability in BSC-related net carbon deposition ranging from 7 to 51 kg ha−1 yr−1.

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