Biological soil crusts in continental Antarctica: Garwood Valley, southern Victoria Land, and Diamond Hill, Darwin Mountains region

2013 ◽  
Vol 26 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Claudia Colesie ◽  
Maxime Gommeaux ◽  
T.G. Allan Green ◽  
Burkhard Büdel
Keyword(s):  
Soil Stabilization ◽  
Higher Plants ◽  
Biological Soil Crusts ◽  
Ecosystem Functions ◽  
Dry Valleys ◽  
Cold Desert ◽  
Chlorophyll Contents ◽  
Green Algal ◽  
Soil Crusts ◽  
Continental Antarctica

AbstractBiological soil crusts are associations of lichens, mosses, algae, cyanobacteria, microfungi and bacteria in different proportions forming a thin veneer within the top centimetres of soil surfaces. They occur in all biomes, but particularly in arid and semi-arid regions, even in the most extreme climates. They carry out crucial ecosystem functions, such as soil stabilization, influencing water and nutrient cycles, and contribute to the formation of microniches for heterotrophic life. In continental Antarctica especially, these roles are essential because no higher plants provide such ecosystem services. We provide a detailed description of biological soil crusts from Garwood Valley, McMurdo Dry Valleys region (78°S) and Diamond Hill (80°S) in the Darwin Mountains region. The coverage was low at 3.3% and 0.8% of the soil surface. At Garwood Valley the crusts were composed of green algal lichens, cyanobacteria, several species of green algae and the mossHennediella heimii(Hedw.) R.H. Zander. Diamond Hill crusts appear to be unique in not having any species of cyanobacteria. Major parts are embedded in the soil, and their thickness correlates with higher chlorophyll contents, higher soil organic carbon and nitrogen, which are fundamental components of this species poor cold desert zone.

scholarly journals Rapidly restoring biological soil crusts and ecosystem functions in a severely disturbed desert ecosystem

2016 ◽  
Vol 26 (4) ◽  
pp. 1260-1272 ◽  
Author(s):  
Lindsay P. Chiquoine ◽  
Scott R. Abella ◽  
Matthew A. Bowker
Keyword(s):  
Biological Soil Crusts ◽  
Desert Ecosystem ◽  
Ecosystem Functions ◽  
Soil Crusts

scholarly journals Warming reduces the growth and diversity of biological soil crusts in a semi-arid environment: implications for ecosystem structure and functioning

2012 ◽  
Vol 367 (1606) ◽  
pp. 3087-3099 ◽  
Author(s):  
Cristina Escolar ◽  
Isabel Martínez ◽  
Matthew A. Bowker ◽  
Fernando T. Maestre
Keyword(s):  
Climate Change ◽  
Soil Stabilization ◽  
Arid Environment ◽  
Biological Soil Crusts ◽  
Water Dynamics ◽  
Annual Rainfall ◽  
Ecosystem Structure ◽  
Positive Effects ◽  
Soil Crusts ◽  
Semi Arid

Biological soil crusts (BSCs) are key biotic components of dryland ecosystems worldwide that control many functional processes, including carbon and nitrogen cycling, soil stabilization and infiltration. Regardless of their ecological importance and prevalence in drylands, very few studies have explicitly evaluated how climate change will affect the structure and composition of BSCs, and the functioning of their constituents. Using a manipulative experiment conducted over 3 years in a semi-arid site from central Spain, we evaluated how the composition, structure and performance of lichen-dominated BSCs respond to a 2.4°C increase in temperature, and to an approximately 30 per cent reduction of total annual rainfall. In areas with well-developed BSCs, warming promoted a significant decrease in the richness and diversity of the whole BSC community. This was accompanied by important compositional changes, as the cover of lichens suffered a substantial decrease with warming (from 70 to 40% on average), while that of mosses increased slightly (from 0.3 to 7% on average). The physiological performance of the BSC community, evaluated using chlorophyll fluorescence, increased with warming during the first year of the experiment, but did not respond to rainfall reduction. Our results indicate that ongoing climate change will strongly affect the diversity and composition of BSC communities, as well as their recovery after disturbances. The expected changes in richness and composition under warming could reduce or even reverse the positive effects of BSCs on important soil processes. Thus, these changes are likely to promote an overall reduction in ecosystem processes that sustain and control nutrient cycling, soil stabilization and water dynamics.

The Role of Biological Soil Crusts in Nitrogen Cycling and Soil Stabilization in Kangerlussuaq, West Greenland

Ecosystems ◽  
2018 ◽  
Vol 22 (2) ◽  
pp. 243-256 ◽  
Author(s):  
Ruth C. Heindel ◽  
Francesca C. Governali ◽  
Angela M. Spickard ◽  
Ross A. Virginia
Keyword(s):  
Nitrogen Cycling ◽  
Soil Stabilization ◽  
Biological Soil Crusts ◽  
West Greenland ◽  
Soil Crusts

scholarly journals Coverage and Rainfall Response of Biological Soil Crusts Using Multi-Temporal Sentinel-2 Data in a Central European Temperate Dry Acid Grassland

2021 ◽  
Vol 13 (16) ◽  
pp. 3093
Author(s):  
Jakob Rieser ◽  
Maik Veste ◽  
Michael Thiel ◽  
Sarah Schönbrodt-Stitt
Keyword(s):  
Biological Soil Crusts ◽  
Classification Model ◽  
Ecosystem Functions ◽  
Temperate Climate ◽  
Higher Plant ◽  
Detection Analysis ◽  
Soil Crusts ◽  
Daily Precipitation Data ◽  
Northeastern Germany ◽  
Sentinel 2

Biological soil crusts (BSCs) are thin microbiological vegetation layers that naturally develop in unfavorable higher plant conditions (i.e., low precipitation rates and high temperatures) in global drylands. They consist of poikilohydric organisms capable of adjusting their metabolic activities depending on the water availability. However, they, and with them, their ecosystem functions, are endangered by climate change and land-use intensification. Remote sensing (RS)-based studies estimated the BSC cover in global drylands through various multispectral indices, and few of them correlated the BSCs’ activity response to rainfall. However, the allocation of BSCs is not limited to drylands only as there are areas beyond where smaller patches have developed under intense human impact and frequent disturbance. Yet, those areas were not addressed in RS-based studies, raising the question of whether the methods developed in extensive drylands can be transferred easily. Our temperate climate study area, the ‘Lieberoser Heide’ in northeastern Germany, is home to the country’s largest BSC-covered area. We applied a Random Forest (RF) classification model incorporating multispectral Sentinel-2 (S2) data, indices derived from them, and topographic information to spatiotemporally map the BSC cover for the first time in Central Europe. We further monitored the BSC response to rainfall events over a period of around five years (June 2015 to end of December 2020). Therefore, we combined datasets of gridded NDVI as a measure of photosynthetic activity with daily precipitation data and conducted a change detection analysis. With an overall accuracy of 98.9%, our classification proved satisfactory. Detected changes in BSC activity between dry and wet conditions were found to be significant. Our study emphasizes a high transferability of established methods from extensive drylands to BSC-covered areas in the temperate climate. Therefore, we consider our study to provide essential impulses so that RS-based biocrust mapping in the future will be applied beyond the global drylands.

scholarly journals Gullies and Moraines Are Islands of Biodiversity in an Arid, Mountain Landscape, Asgard Range, Antarctica

2021 ◽  
Vol 12 ◽  
Author(s):  
Adam J. Solon ◽  
Claire Mastrangelo ◽  
Lara Vimercati ◽  
Pacifica Sommers ◽  
John L. Darcy ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Amplicon Sequencing ◽  
Phototrophic Bacteria ◽  
Rrna Gene ◽  
Dry Valleys ◽  
Habitat Types ◽  
Desert Ecosystems ◽  
High Sequence Identity ◽  
Cold Desert ◽  
Soil Crusts

Cold, dry, and nutrient-poor, the McMurdo Dry Valleys of Antarctica are among the most extreme terrestrial environments on Earth. Numerous studies have described microbial communities of low elevation soils and streams below glaciers, while less is known about microbial communities in higher elevation soils above glaciers. We characterized microbial life in four landscape features (habitats) of a mountain in Taylor Valley. These habitats varied significantly in soil moisture and include moist soils of a (1) lateral glacial moraine, (2) gully that terminates at the moraine, and very dry soils on (3) a southeastern slope and (4) dry sites near the gully. Using rRNA gene PCR amplicon sequencing of Bacteria and Archaea (16S SSU) and eukaryotes (18S SSU), we found that all habitat types harbored significantly different bacterial and eukaryotic communities and that these differences were most apparent when comparing habitats that had macroscopically visible soil crusts (gully and moraine) to habitats with no visible crusts (near gully and slope). These differences were driven by a relative predominance of Actinobacteria and a Colpodella sp. in non-crust habitats, and by phototrophic bacteria and eukaryotes (e.g., a moss) and predators (e.g., tardigrades) in habitats with biological soil crusts (gully and moraine). The gully and moraine also had significantly higher 16S and 18S ESV richness than the other two habitat types. We further found that many of the phototrophic bacteria and eukaryotes of the gully and moraine share high sequence identity with phototrophs from moist and wet areas elsewhere in the Dry Valleys and other cold desert ecosystems. These include a Moss (Bryum sp.), several algae (e.g., a Chlorococcum sp.) and cyanobacteria (e.g., Nostoc and Phormidium spp.). Overall, the results reported here broaden the diversity of habitat types that have been studied in the Dry Valleys of Antarctica and suggest future avenues of research to more definitively understand the biogeography and factors controlling microbial diversity in this unique ecosystem.

scholarly journals Uncovering biological soil crusts: Carbon content and structure of intact Arctic, Antarctic and alpine biological soil crusts

2017 ◽  
Author(s):  
Patrick Jung ◽  
Laura Briegel-Williams ◽  
Anika Simon ◽  
Anne Thyssen ◽  
Burkhard Büdel
Keyword(s):  
Green Algae ◽  
Laser Scanning ◽  
Biological Soil Crusts ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Soil Organic C ◽  
Organic C ◽  
Green Algal ◽  
Soil Crusts ◽  
Degradation Rates

Abstract. Arctic, Antarctic and alpine biological soil crusts (BSCs) are formed by adhesion of soil particles to exopolysaccharides (EPS), excreted by cyanobacterial and green algal communities, the pioneers and main producers in these habitats. These BSCs provide and influence many ecosystem services such as soil erodibility, soil formation and Nitrogen- (N) as well as carbon- (C) cycles. In cold environments degradation rates are low and BSCs increase continuously soil organic C, whereby these soils are considered as CO2 sinks. This work provides a novel, non-destructive and highly comparable method to investigate intact BSCs with a focus on cyanobacteria and green algae and their contribution to soil organic C. A new terminology arose, based on confocal laser scanning microscopy (CLSM) 2D biomaps, dividing BSCs into a photosynthetic active layer (PAL), made of active photoautotrophic organisms and a photosynthetic inactive layer (PIL), harbouring remnants of cyanobacteria and green algae glued together by their remaining EPS. By the application of CLSM image analysis (CLSM-IA) to 3D biomaps, C coming from photosynthetic active organisms could be visualized as depth profiles with C peaks at 0.5 to 2 mm depth. Additionally, the CO2 sink character of these cold soil habitats dominated by BSCs could be highlighted, demonstrating that the first cm3 of soil is made of between 7 and 17 % total organic carbon, identified by loss on ignition.

scholarly journals Optimizing the Production of Nursery-Based Biological Soil Crusts for Restoration of Arid Land Soils

2019 ◽  
Vol 85 (15) ◽  
Author(s):  
Julie Bethany ◽  
Ana Giraldo-Silva ◽  
Corey Nelson ◽  
Nichole N. Barger ◽  
Ferran Garcia-Pichel
Keyword(s):  
Ecosystem Services ◽  
Soil Fertility ◽  
Erosion Resistance ◽  
Growth Dynamics ◽  
Biological Soil Crusts ◽  
Livestock Grazing ◽  
Arid Land ◽  
Cold Desert ◽  
Area Of Interest ◽  
Soil Crusts

ABSTRACTBiological soil crusts (biocrusts) are topsoil communities formed by cyanobacteria or other microbial primary producers and are typical of arid and semiarid environments. Biocrusts promote a range of ecosystem services, such as erosion resistance and soil fertility, but their degradation by often anthropogenic disturbance brings about the loss of these services. This has prompted interest in developing restoration techniques. One approach is to source biocrust remnants from the area of interest for scale-up cultivation in a microbial “nursery” that produces large quantities of high-quality inoculum for field deployment. However, growth dynamics and the ability to reuse the produced inoculum for continued production have not been assessed. To optimize production, we followed nursery growth dynamics of biocrusts from cold (Great Basin) and hot (Chihuahuan) deserts. Peak phototrophic biomass was attained between 3 and 7 weeks in cold desert biocrusts and at 12 weeks in those from hot deserts. We also reused the resultant biocrust inoculum to seed successive incubations, tracking both phototroph biomass and cyanobacterial community structure using 16S rRNA gene amplicon sequencing. Hot desert biocrusts showed little to no viability upon reinoculation, while cold desert biocrusts continued to grow, but at the expense of progressive shifts in species composition. This leads us to discourage the reuse of nursery-grown inoculum. Surprisingly, growth was highly variable among replicates, and overall yields were low, a fact that we attribute to the demonstrable presence of virulent and stochastically distributed but hitherto unknown cyanobacterial pathogens. We provide recommendations to avoid pathogen incidence in the process.IMPORTANCEBiocrust communities provide important ecosystem services for arid land soils, such as soil surface stabilization promoting erosion resistance and contributing to overall soil fertility. Anthropogenic degradation to biocrust communities (through livestock grazing, agriculture, urban sprawl, and trampling) is common and significant, resulting in a loss of those ecosystem services. Losses impact both the health of the native ecosystem and the public health of local populations due to enhanced dust emissions. Because of this, approaches for biocrust restoration are being developed worldwide. Here, we present optimization of a nursery-based approach to scaling up the production of biocrust inoculum for field restoration with respect to temporal dynamics and reuse of biological materials. Unexpectedly, we also report on complex population dynamics, significant spatial variability, and lower than expected yields that we ascribe to the demonstrable presence of cyanobacterial pathogens, the spread of which may be enhanced by some of the nursery production standard practices.

scholarly journals Microstructure and hydraulic properties of biological soil crusts on sand dunes: a comparison between arid and temperate climates

2012 ◽  
Vol 9 (9) ◽  
pp. 12711-12734 ◽  
Author(s):  
T. Fischer ◽  
A. Yair ◽  
M. Veste
Keyword(s):  
Water Supply ◽  
Fine Particles ◽  
Water Saturation ◽  
Higher Plants ◽  
Sand Dunes ◽  
Biological Soil Crusts ◽  
Water Holding Capacity ◽  
Soil Crusts ◽  
Water Holding ◽  
Dune Crest

Abstract. We studied the relationships between crust microstructure, infiltration and water holding capacity under arid and temperate conditions (Factor A: Climate) on biological soil crusts (BSCs) sampled along a~catena on mobile sand dunes (Factor B: Catena). The arid study site was located near Nizzana, Israel (precipitation: 86 mm a−1, PET: ~2500 mm a−1) and the temperate site near Lieberose, Germany (precipitation: 569 mm a−1, PET: ~780 mm a−1). BSCs were sampled near the dune crest, at the centre of the dune slope and at the dune base at each site. Scanning electron microscopy (SEM) was used to characterize BSC morphology and microstructure. Infiltration was determined using microinfiltrometry under controlled moisture conditions in the lab. Water holding capacities were determined after water saturation of the dry BSCs. Wettability of the crusts was characterized using a "repellency index", which was calculated from water and ethanol sorptivities. Irrespective of the climate, an accumulation of fine particles in the BSCs was found, increasing along the catena from dune crest to dune base. Texture was finer and water holding capacities of the underlying substrate were higher at the arid site, whereas surface wettability was reduced at the temperate site. At both sites, BSCs caused extra water holding capacity compared to the substrate. Infiltration rates decreased along the catena and were generally lower at the dune slope and base of the arid site. A mechanism of crust stabilization is proposed where BSCs benefit from increased texture and biomass mediated water supply, and where the water supply to higher plants was limited due to alteration of physico-chemical surface properties under temperate conditions.

scholarly journals Uncovering biological soil crusts: carbon content and structure of intact Arctic, Antarctic and alpine biological soil crusts

2018 ◽  
Vol 15 (4) ◽  
pp. 1149-1160 ◽  
Author(s):  
Patrick Jung ◽  
Laura Briegel-Williams ◽  
Anika Simon ◽  
Anne Thyssen ◽  
Burkhard Büdel
Keyword(s):  
Green Algae ◽  
Laser Scanning ◽  
Biological Soil Crusts ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Soil Organic C ◽  
Organic C ◽  
Green Algal ◽  
Soil Crusts ◽  
Degradation Rates

Abstract. Arctic, Antarctic and alpine biological soil crusts (BSCs) are formed by adhesion of soil particles to exopolysaccharides (EPSs) excreted by cyanobacterial and green algal communities, the pioneers and main primary producers in these habitats. These BSCs provide and influence many ecosystem services such as soil erodibility, soil formation and nitrogen (N) and carbon (C) cycles. In cold environments degradation rates are low and BSCs continuously increase soil organic C; therefore, these soils are considered to be CO2 sinks. This work provides a novel, non-destructive and highly comparable method to investigate intact BSCs with a focus on cyanobacteria and green algae and their contribution to soil organic C. A new terminology arose, based on confocal laser scanning microscopy (CLSM) 2-D biomaps, dividing BSCs into a photosynthetic active layer (PAL) made of active photoautotrophic organisms and a photosynthetic inactive layer (PIL) harbouring remnants of cyanobacteria and green algae glued together by their remaining EPSs. By the application of CLSM image analysis (CLSM–IA) to 3-D biomaps, C coming from photosynthetic active organisms could be visualized as depth profiles with C peaks at 0.5 to 2 mm depth. Additionally, the CO2 sink character of these cold soil habitats dominated by BSCs could be highlighted, demonstrating that the first cubic centimetre of soil consists of between 7 and 17 % total organic carbon, identified by loss on ignition.

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