Biological Soil Crusts as an Organizing Principle in Drylands

Belnap, Jayne; Weber, Bettina; Büdel, Burkhard

doi:10.1007/978-3-319-30214-0_1

Cited by 250 publications

(207 citation statements)

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“…They cover dryland soil surfaces and can compose up to 70 % of a dryland ecosystem's living cover (Belnap, 1995;Belnap et al, 2016), but also occur in other climatic regions where competition with vascular plants is low (Büdel, 2001;Büdel et al, 2014). Due to the poikilohydric character of biocrust organisms, biocrusts exhibit high resilience under extreme conditions and have a remarkable adaptation to various combinations of climatic factors (e.g.…”

Section: Introductionmentioning

confidence: 99%

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

2018

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Abstract. Biological soil crusts (biocrusts) are a common element of the Queensland (Australia) dry savannah ecosystem and are composed of cyanobacteria, algae, lichens, bryophytes, fungi and heterotrophic bacteria. Here we report how the CO 2 gas exchange of the cyanobacteria-dominated biocrust type from Boodjamulla National Park in the north Queensland Gulf Savannah responds to the pronounced climatic seasonality and on their quality as a carbon sink using a semi-automatic cuvette system. The dominant cyanobacteria are the filamentous species Symplocastrum purpurascens together with Scytonema sp. Metabolic activity was recorded between 1 July 2010 and 30 June 2011, during which CO 2 exchange was only evident from November 2010 until mid-April 2011, representative of 23.6 % of the 1-year recording period. In November at the onset of the wet season, the first month (November) and the last month (April) of activity had pronounced respiratory loss of CO 2 . The metabolic active period accounted for 25 % of the wet season and of that period 48.6 % was net photosynthesis (NP) and 51.4 % dark respiration (DR). During the time of NP, net photosynthetic uptake of CO 2 during daylight hours was reduced by 32.6 % due to water supersaturation. In total, the biocrust fixed 229.09 mmol CO 2 m −2 yr −1 , corresponding to an annual carbon gain of 2.75 g m −2 yr −1 . Due to malfunction of the automatic cuvette system, data from September and October 2010 together with some days in November and December 2010 could not be analysed for NP and DR. Based on climatic and gas exchange data from November 2010, an estimated loss of 88 mmol CO 2 m −2 was found for the 2 months, resulting in corrected annual rates of 143.1 mmol CO 2 m −2 yr −1 , equivalent to a carbon gain of 1.7 g m −2 yr −1 . The bulk of the net photosynthetic activity occurred above a relative humidity of 42 %, indicating a suitable climatic combination of temperature, water availability and light intensity well above 200 µmol photons m −2 s −1 photosynthetic active radiation. The Boodjamulla biocrust exhibited high seasonal variability in CO 2 gas exchange pattern, clearly divided into metabolically inactive winter months and active summer months. The metabolic active period commences with a period (of up to 3 months) of carbon loss, likely due to reestablishment of the crust structure and restoration of NP prior to about a 4-month period of net carbon gain. In the Gulf Savannah biocrust system, seasonality over the year investigated showed that only a minority of the year is actually suitable for biocrust growth and thus has a small window for potential contribution to soil organic matter.

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Section: Introductionmentioning

confidence: 99%

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

2018

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“…Karsten et al, 2010a, 2010b, Karsten, 2013, which could have changed their eco-physiological responses over time, as these organisms are well known to have a high acclimatization potential to differing environmental factors (Dietz et al, 2000;Nash, 2008;Colesie et al, 2012;Belnap et al, 2016).…”

Section: ;mentioning

confidence: 99%

“…Areas where vegetation remains in an arrested succession are appearing more frequently due to a growing need for space by humans (Housman, 2006). New habitats derived from accelerating human activities are fairly 20 understudied (Rindi, 2007;Belnap et al, 2016).…”

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confidence: 99%

Eco-physiological characterization of early successional biological soil crusts in heavily human impacted areas – Implications for conservation and succession

Szyja

Büdel

Colesie

2017

Preprint

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Abstract. Eco-physiological characterization of photoautotrophic communities is not only necessary to identify the response of carbon fixation related to different climatic factors, but also to evaluate risks connected to changing environments. In 10 biological soil crusts (BSCs), the description of eco-physiological features is difficult, due to the high variability in taxonomic composition and variable methodologies applied. Especially for BSCs in early successional stages, the available datasets are rare or focused on individual constituents, although these crusts may represent the only photoautotrophic component in many heavily disturbed ruderal areas, like parking lots or building areas with increasing surface area worldwide. We analyzed the response of photosynthesis and respiration to changing BSC water contents, temperature and 15 light in two early successional BSCs. One BSC was dominated by the cyanobacterium Nostoc commune, the other by the green alga Zygogonium ericetorum. Independent of species composition, both crust types had convergent features like high light acclimatization and low or no depression in carbon uptake at water suprasaturation. This particular setup of ecophysiological features may enable these communities to cope with a high variety of climatic stresses, and may therefore be a reason for their success in heavily disturbed areas with ongoing human impact. Nevertheless, a major divergence between 20 the two BSCs was their absolute carbon fixation rate on a chlorophyll basis, which was significantly higher for the cyanobacterial crust. This study emphasizes the importance of measuring intact BSCs under natural conditions for collecting reliable data.

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“…They grow within the uppermost millimeters of the soil in close association with soil particles. It has been shown that biocrusts play significant functional roles in desert ecosystems (Eldridge and Greene, 1994;Evans and Belnap, 1999;Lan et al, 2011), as they stabilize the soil surface and reduce erosion by wind and water (Zhao et al, 2014;Belnap et al, 2014;Belnap and Büdel, 2016), they contribute to soil fertility through carbon and nitrogen fixation (Elbert et al, 2012;Sancho et al, 2016;Barger et al, 2016;Brankatschk et al, 2013), and they positively affect water retention and distribution in drylands (RodriguezCaballero et al, 2014;Chamizo et al, 2016). Biocrusts and their organisms have also been shown to release gaseous nitrogen compounds, as nitrous acid (Lenhart et al, 2015), nitric oxide, and nitrous oxide into the atmosphere Meusel et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll a and chlorophyll a + b as compared to previous methods

et al. 2018

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Abstract. Chlorophyll concentrations of biological soil crust (biocrust) samples are commonly determined to quantify the relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure, and the impact of shaking as an intermediate step during extraction. The analyses were conducted on four different types of biocrusts. Our results show that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained using dimethyl sulfoxide (DMSO) as a solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen- and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss- and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of green algal lichen- and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest the addition of an intermediate shaking step for complete chlorophyll extraction (see Supplement S6 for detailed manual). Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of publications conducted across all continents.

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Biological Soil Crusts as an Organizing Principle in Drylands

Cited by 250 publications

References 22 publications

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

Eco-physiological characterization of early successional biological soil crusts in heavily human impacted areas – Implications for conservation and succession

Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll <i>a</i> and chlorophyll <i>a</i> + <i>b</i> as compared to previous methods

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Biological Soil Crusts as an Organizing Principle in Drylands

Cited by 250 publications

References 22 publications

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

Eco-physiological characterization of early successional biological soil crusts in heavily human impacted areas – Implications for conservation and succession

Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll &lt;i&gt;a&lt;/i&gt; and chlorophyll &lt;i&gt;a&lt;/i&gt; + &lt;i&gt;b&lt;/i&gt; as compared to previous methods

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Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll <i>a</i> and chlorophyll <i>a</i> + <i>b</i> as compared to previous methods