CO<sub>2</sub> fluxes of cryptogamic crusts

Jeffries, Douglas L.; Link, Steven O.; Klopatek, Jeffrey M.

doi:10.1111/j.1469-8137.1993.tb03874.x

Cited by 59 publications

(30 citation statements)

References 29 publications

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“…Lowest rates of C uptake were reported from a cyanobacteria-dominant crust in the Kaiparowits Basin in southern Utah at 0.8 g m 22 yr 21 [63]. Highest uptake rates were reported from well-developed BSCs in the pinyon-juniper woodlands in the Utah Canyonlands of 74.9 g m 22 yr 21 [64].…”

Section: Discussionmentioning

confidence: 97%

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO ₂ efflux in two semiarid grasslands in southern Botswana

Thomas

2012

Phil. Trans. R. Soc. B

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Biological soil crusts (BSCs) are an important source of organic carbon, and affect a range of ecosystem functions in arid and semiarid environments. Yet the impact of grazing disturbance on crust properties and soil CO 2 efflux remain poorly studied, particularly in African ecosystems. The effects of burial under wind-blown sand, disaggregation and removal of BSCs on seasonal variations in soil CO 2 efflux, soil organic carbon, chlorophyll a and scytonemin were investigated at two sites in the Kalahari of southern Botswana. Field experiments were employed to isolate CO 2 efflux originating from BSCs in order to estimate the C exchange within the crust. Organic carbon was not evenly distributed through the soil profile but concentrated in the BSC. Soil CO 2 efflux was higher in Kalahari Sand than in calcrete soils, but rates varied significantly with seasonal changes in moisture and temperature. BSCs at both sites were a small net sink of C to the soil. Soil CO 2 efflux was significantly higher in sand soils where the BSC was removed, and on calcrete where the BSC was buried under sand. The BSC removal and burial under sand also significantly reduced chlorophyll a, organic carbon and scytonemin. Disaggregation of the soil crust, however, led to increases in chlorophyll a and organic carbon. The data confirm the importance of BSCs for C cycling in drylands and indicate intensive grazing, which destroys BSCs through trampling and burial, will adversely affect C sequestration and storage. Managed grazing, where soil surfaces are only lightly disturbed, would help maintain a positive carbon balance in African drylands.

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Section: Discussionmentioning

confidence: 97%

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO ₂ efflux in two semiarid grasslands in southern Botswana

Thomas

2012

Phil. Trans. R. Soc. B

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“…For instance, maximum net CO 2 deposition to BSC dominated by Collema tenax and Microcoleus sp. were -5.3 and -0.187 µmol m −2 s −1 under laboratory conditions, respectively (Jeffries et al, 1993;Lange et al, 1998). In this study, BSC consisted of cyanobacteria (Microcoleus), lichens (Collema), and mosses in similar contributions, and the highest 10-min mean CO 2 deposition was -1.71 µmol m −2 s −1 with individual values during the same interval reaching up to 2.15 µmol m −2 s −1 .…”

Section: Bsc-related Co 2 Fluxes and Soil Effluxmentioning

confidence: 99%

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

et al. 2008

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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 welldeveloped BSC in undisturbed steppe systems. Mobile enclosures on permanent soil borne collars were used to investigate BSC-related CO 2 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 CO 2 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 CO 2 deposition by BSC was calculated to compensate 120%, -26%, and less than 3% of the concurrent soil CO

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“…The global estimate of net carbon uptake by lichens and bryophytes amounts to 0.34 (Gt C) yr −1 for the averageweighting method and 3.3 (Gt C) yr −1 for the maximum- (Oechel and Collins, 1976) Tundra 38.5-171 (2) (Schuur et al, 2007) Tundra 12-60 (3) (Shaver and Chapin III, 1991) Tundra 2-68 (4) (Uchida et al, 2006) Tundra 1.9 (Uchida et al, 2002) Tundra 6.5 (Billings, 1987) Boreal forest 9.7-78 (2) (Bisbee et al, 2001) Boreal forest 25 (Camill et al, 2001) Boreal forest 9.2-75.9 (8) (Gower et al, 1997) Boreal forest 12 (Grigal, 1985) Boreal forest 128-152 (2) (Harden et al, 1997) Boreal forest 60-280 (3) (Bond-Lamberty et al, 2004) Boreal forest 0-297.1 (14) Boreal forest 0.4-16.2 (7) (Oechel and Van Cleve, 1986) Boreal forest 40-44 (2) (Reader and Stewart, 1972) Boreal forest 14.4 (Ruess et al, 2003) Boreal forest 29.2-31.2 (2) (Swanson and Flanagan, 2001) Boreal forest 104 (Szumigalski and Bayley, 1996) Boreal forest 15.2-81.2 (10) (Thormann, 1995) Boreal forest 23.2-73.2 (3) Boreal forest 12-32 (9) (Wieder and Lang, 1983) Boreal forest 216-316 (3) (Brostoff et al, 2005) Desert 11.7 (Garcia-Pichel and Belnap, 1996) Desert 0.54 (Jeffries et al, 1993) Desert 0.07-1.5 (3) (Klopatek, 1992) Desert 5.3-29 (4) (Clark et al, 1998) Tropical forest 37-64 (2) weighting method (for a description of these weighting methods see Sect. 2.3).…”

Section: Modelled Net Carbon Uptakementioning

confidence: 99%

Estimating global carbon uptake by lichens and bryophytes with a process-based model

et al. 2013

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Abstract. Lichens and bryophytes are abundant globally and they may even form the dominant autotrophs in (sub)polar ecosystems, in deserts and at high altitudes. Moreover, they can be found in large amounts as epiphytes in old-growth forests. Here, we present the first process-based model which estimates the net carbon uptake by these organisms at the global scale, thus assessing their significance for biogeochemical cycles. The model uses gridded climate data and key properties of the habitat (e.g. disturbance intervals) to predict processes which control net carbon uptake, namely photosynthesis, respiration, water uptake and evaporation. It relies on equations used in many dynamical vegetation models, which are combined with concepts specific to lichens and bryophytes, such as poikilohydry or the effect of water content on CO 2 diffusivity. To incorporate the great functional variation of lichens and bryophytes at the global scale, the model parameters are characterised by broad ranges of possible values instead of a single, globally uniform value. The predicted terrestrial net uptake of 0.34 to 3.3 Gt yr −1 of carbon and global patterns of productivity are in accordance with empirically-derived estimates. Considering that the assimilated carbon can be invested in processes such as weathering or nitrogen fixation, lichens and bryophytes may play a significant role in biogeochemical cycles.

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CO₂ fluxes of cryptogamic crusts

Cited by 59 publications

References 29 publications

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO ₂ efflux in two semiarid grasslands in southern Botswana

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO ₂ efflux in two semiarid grasslands in southern Botswana

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

Estimating global carbon uptake by lichens and bryophytes with a process-based model

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CO2 fluxes of cryptogamic crusts

Cited by 59 publications

References 29 publications

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO 2 efflux in two semiarid grasslands in southern Botswana

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO 2 efflux in two semiarid grasslands in southern Botswana

The CO&lt;sub&gt;2&lt;/sub&gt; exchange of biological soil crusts in a semiarid grass-shrubland at the northern transition zone of the Negev desert, Israel

Estimating global carbon uptake by lichens and bryophytes with a process-based model

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Product

Resources

About

CO₂ fluxes of cryptogamic crusts

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO ₂ efflux in two semiarid grasslands in southern Botswana

Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO ₂ efflux in two semiarid grasslands in southern Botswana

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