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

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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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

Biogeosciences Discussions ◽

10.5194/bgd-5-1969-2008 ◽

2008 ◽

Vol 5 (3) ◽

pp. 1969-2001 ◽

Cited By ~ 16

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.

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Carbon dioxide fluxes and carbon balance of an agricultural grassland in southern Finland

10.5194/bg-2020-422 ◽

2020 ◽

Author(s):

Laura Heimsch ◽

Annalea Lohila ◽

Juha-Pekka Tuovinen ◽

Henriikka Vekuri ◽

Jussi Heinonsalo ◽

...

Keyword(s):

Leaf Area ◽

Carbon Balance ◽

Significant Proportion ◽

Flux Measurement ◽

Co2 Fluxes ◽

Carbon Dioxide Fluxes ◽

Area Index ◽

Soil Carbon Content ◽

Management Measures ◽

Annual Carbon

Abstract. A significant proportion of the global carbon emissions to the atmosphere originates from agriculture. Therefore, continuous long-term monitoring of CO2 fluxes is essential to understand the carbon dynamics and balances of different agricultural sites. Here we present results from a new eddy covariance flux measurement site located in southern Finland. We measured CO2 and H2O fluxes at this agricultural grassland site for two years from May 2018 to May 2020. Especially the first summer experienced prolonged dry periods, which affected the CO2 fluxes, and substantially larger fluxes were observed in the second summer. During the dry summer, leaf area index (LAI) was notably lower than in the second summer. Water use efficiency increased with LAI in a similar manner in both years, but photosynthetic capacity per leaf area was lower during the dry summer. The annual carbon balance was calculated based on the CO2 fluxes and management measures, which included input of carbon as organic fertilisers and output as yield. The carbon balance of the field was −50 ± 68 g C m−2 yr−1 and −118 ± 24 g C m−2 yr−1 during the first and second study year, respectively. We estimated that on average the grassland exceeded the global 4 per 1000 goal to increase the soil carbon content.

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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

Biogeosciences ◽

10.5194/bg-5-1411-2008 ◽

2008 ◽

Vol 5 (5) ◽

pp. 1411-1423 ◽

Cited By ~ 36

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.

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Carbon dioxide fluxes and carbon balance of an agricultural grassland in southern Finland

Biogeosciences ◽

10.5194/bg-18-3467-2021 ◽

2021 ◽

Vol 18 (11) ◽

pp. 3467-3483

Author(s):

Laura Heimsch ◽

Annalea Lohila ◽

Juha-Pekka Tuovinen ◽

Henriikka Vekuri ◽

Jussi Heinonsalo ◽

...

Keyword(s):

Leaf Area ◽

Carbon Balance ◽

Significant Proportion ◽

Flux Measurement ◽

Organic Fertilizers ◽

Co2 Fluxes ◽

Carbon Dioxide Fluxes ◽

Area Index ◽

Management Measures ◽

Annual Carbon

Abstract. A significant proportion of the global carbon emissions to the atmosphere originate from agriculture. Therefore, continuous long-term monitoring of CO2 fluxes is essential to understand the carbon dynamics and balances of different agricultural sites. Here we present results from a new eddy covariance flux measurement site located in southern Finland. We measured CO2 and H2O fluxes at this agricultural grassland site for 2 years, from May 2018 to May 2020. In particular the first summer experienced prolonged dry periods, which affected the CO2 fluxes, and substantially larger fluxes were observed in the second summer. During the dry summer, leaf area index (LAI) was notably lower than in the second summer. Water use efficiency increased with LAI in a similar manner in both years, but photosynthetic capacity per leaf area was lower during the dry summer. The annual carbon balance was calculated based on the CO2 fluxes and management measures, which included input of carbon as organic fertilizers and output as yield. The carbon balance of the field was −57 ± 10 and −86 ± 12 g C m−2 yr−1 in the first and second study years, respectively.

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Bryophyte-dominated biological soil crusts mitigate soil erosion in an early successional Chinese subtropical forest

Biogeosciences ◽

10.5194/bg-14-5775-2017 ◽

2017 ◽

Vol 14 (24) ◽

pp. 5775-5788 ◽

Cited By ~ 14

Author(s):

Steffen Seitz ◽

Martin Nebel ◽

Philipp Goebes ◽

Kathrin Käppeler ◽

Karsten Schmidt ◽

...

Keyword(s):

Soil Erosion ◽

Ecosystem Functioning ◽

Early Stage ◽

Biological Soil Crusts ◽

Subtropical Forest ◽

Sediment Delivery ◽

Area Index ◽

Terrain Attributes ◽

Soil Crusts ◽

Biodiversity And Ecosystem Functioning

Abstract. This study investigated the development of biological soil crusts (biocrusts) in an early successional subtropical forest plantation and their impact on soil erosion. Within a biodiversity and ecosystem functioning experiment in southeast China (biodiversity and ecosystem functioning (BEF) China), the effect of these biocrusts on sediment delivery and runoff was assessed within micro-scale runoff plots under natural rainfall, and biocrust cover was surveyed over a 5-year period. Results showed that biocrusts occurred widely in the experimental forest ecosystem and developed from initial light cyanobacteria- and algae-dominated crusts to later-stage bryophyte-dominated crusts within only 3 years. Biocrust cover was still increasing after 6 years of tree growth. Within later-stage crusts, 25 bryophyte species were determined. Surrounding vegetation cover and terrain attributes significantly influenced the development of biocrusts. Besides high crown cover and leaf area index, the development of biocrusts was favoured by low slope gradients, slope orientations towards the incident sunlight and the altitude of the research plots. Measurements showed that bryophyte-dominated biocrusts strongly decreased soil erosion, being more effective than abiotic soil surface cover. Hence, their significant role in mitigating sediment delivery and runoff generation in mesic forest environments and their ability to quickly colonise soil surfaces after disturbance are of particular interest for soil erosion control in early-stage forest plantations.

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