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Yang Z, Yuan Y, Guo J, Li J, Li J, Yu H, Zeng W, Huang Y, Yin L, Li F. Responses of Soil C, N, P and Enzyme Activities to Biological Soil Crusts in China: A Meta-Analysis. PLANTS (BASEL, SWITZERLAND) 2024; 13:1525. [PMID: 38891333 PMCID: PMC11174547 DOI: 10.3390/plants13111525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024]
Abstract
Biological soil crusts (BSCs) are often referred to as the "living skin" of arid regions worldwide. Yet, the combined impact of BSCs on soil carbon (C), nitrogen (N), phosphorus (P), and enzyme activities remains not fully understood. This study identified, screened and reviewed 71 out of 2856 literature sources to assess the responses of soil C, N, P and enzyme activity to BSCs through a meta-analysis. The results indicated that BSC presence significantly increased soil C, N, P and soil enzyme activity, and this increasing effect was significantly influenced by the types of BSCs. Results from the overall effect showed that soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP), and available phosphorus (AP) increased by 107.88%, 84.52%, 45.43%, 27.46%, and 54.71%, respectively, and four soil enzyme activities (Alkaline Phosphatase, Cellulase, Sucrase, and Urease) increased by 93.65-229.27%. The highest increases in SOC, TN and AN content occurred in the soil covered with lichen crusts and moss crusts, and significant increases in Alkaline Phosphatase and Cellulase were observed in the soil covered with moss crusts and mixed crusts, suggesting that moss crusts can synergistically enhance soil C and N pool and enzyme activity. Additionally, variations in soil C, N, P content, and enzyme activity were observed under different environmental settings, with more pronounced improvements seen in coarse and medium-textured soils compared to fine-textured soils, particularly at a depth of 5 cm from the soil surface. BSCs in desert ecosystems showed more significant increases in SOC, TN, AN, and Alkaline Phosphatase compared to forest and grassland ecosystems. Specifically, BSCs at low altitude (≤500 m) with an annual average rainfall of 0-400 mm and an annual average temperature ≤ 10 °C were the most conducive to improving soil C, N, and P levels. Our results highlight the role of BSCs and their type in increasing soil C, N, P and enzyme activities, with these effects significantly impacted by soil texture, ecosystem type, and climatic conditions. The implications of these findings are crucial for soil enhancement, ecosystem revitalization, windbreak, and sand stabilization efforts in the drylands of China.
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Affiliation(s)
- Zhi Yang
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Yong Yuan
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Jinjin Guo
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Jinxi Li
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Jianhua Li
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Hu Yu
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Wen Zeng
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Yinhong Huang
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Liyun Yin
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
| | - Fulian Li
- Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China; (Z.Y.); (J.L.); (J.L.); (H.Y.); (W.Z.); (Y.H.); (L.Y.); (F.L.)
- Yunnan Provincial Field Scientific Observation and Research Station on Water-Soil-Crop System in Seasonal Arid Region, Kunming University of Science and Technology, Kunming 650500, China
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Sorochkina K, Martens-Habbena W, Reardon CL, Inglett PW, Strauss SL. Nitrogen-fixing bacterial communities differ between perennial agroecosystem crops. FEMS Microbiol Ecol 2024; 100:fiae064. [PMID: 38637314 DOI: 10.1093/femsec/fiae064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/28/2024] [Accepted: 04/17/2024] [Indexed: 04/20/2024] Open
Abstract
Biocrusts, common in natural ecosystems, are specific assemblages of microorganisms at or on the soil surface with associated microorganisms extending into the top centimeter of soil. Agroecosystem biocrusts have similar rates of nitrogen (N) fixation as those in natural ecosystems, but it is unclear how agricultural management influences their composition and function. This study examined the total bacterial and diazotrophic communities of biocrusts in a citrus orchard and a vineyard that shared a similar climate and soil type but differed in management. To contrast climate and soil type, these biocrusts were also compared with those from an apple orchard. Unlike natural ecosystem biocrusts, these agroecosystem biocrusts were dominated by proteobacteria and had a lower abundance of cyanobacteria. All of the examined agroecosystem biocrust diazotroph communities were dominated by N-fixing cyanobacteria from the Nostocales order, similar to natural ecosystem cyanobacterial biocrusts. Lower irrigation and fertilizer in the vineyard compared with the citrus orchard could have contributed to biocrust microbial composition, whereas soil type and climate could have differentiated the apple orchard biocrust. Season did not influence the bacterial and diazotrophic community composition of any of these agroecosystem biocrusts. Overall, agricultural management and climatic and edaphic factors potentially influenced the community composition and function of these biocrusts.
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Affiliation(s)
- Kira Sorochkina
- Department of Soil, Water, and Ecosystem Sciences, University of Florida, Gainesville, FL, United States
- Southwest Research and Education Center, University of Florida, Immokalee, FL, United States
| | - Willm Martens-Habbena
- Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, FL, United States
| | - Catherine L Reardon
- Soil and Water Conservation Research Unit, U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Pendleton, OR, United States
| | - Patrick W Inglett
- Department of Soil, Water, and Ecosystem Sciences, University of Florida, Gainesville, FL, United States
| | - Sarah L Strauss
- Department of Soil, Water, and Ecosystem Sciences, University of Florida, Gainesville, FL, United States
- Southwest Research and Education Center, University of Florida, Immokalee, FL, United States
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Tariq A, Graciano C, Sardans J, Zeng F, Hughes AC, Ahmed Z, Ullah A, Ali S, Gao Y, Peñuelas J. Plant root mechanisms and their effects on carbon and nutrient accumulation in desert ecosystems under changes in land use and climate. THE NEW PHYTOLOGIST 2024; 242:916-934. [PMID: 38482544 DOI: 10.1111/nph.19676] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 02/27/2024] [Indexed: 04/12/2024]
Abstract
Deserts represent key carbon reservoirs, yet as these systems are threatened this has implications for biodiversity and climate change. This review focuses on how these changes affect desert ecosystems, particularly plant root systems and their impact on carbon and mineral nutrient stocks. Desert plants have diverse root architectures shaped by water acquisition strategies, affecting plant biomass and overall carbon and nutrient stocks. Climate change can disrupt desert plant communities, with droughts impacting both shallow and deep-rooted plants as groundwater levels fluctuate. Vegetation management practices, like grazing, significantly influence plant communities, soil composition, root microorganisms, biomass, and nutrient stocks. Shallow-rooted plants are particularly susceptible to climate change and human interference. To safeguard desert ecosystems, understanding root architecture and deep soil layers is crucial. Implementing strategic management practices such as reducing grazing pressure, maintaining moderate harvesting levels, and adopting moderate fertilization can help preserve plant-soil systems. Employing socio-ecological approaches for community restoration enhances carbon and nutrient retention, limits desert expansion, and reduces CO2 emissions. This review underscores the importance of investigating belowground plant processes and their role in shaping desert landscapes, emphasizing the urgent need for a comprehensive understanding of desert ecosystems.
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Affiliation(s)
- Akash Tariq
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- CSIC, Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra, 08193, Barcelona, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain
| | - Corina Graciano
- Instituto de Fisiología Vegetal, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de La Plata, 1900, Buenos Aires, Argentina
| | - Jordi Sardans
- CSIC, Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra, 08193, Barcelona, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain
| | - Fanjiang Zeng
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Alice C Hughes
- School of Biological Sciences, University of Hong Kong, Hong Kong, 852, China
| | - Zeeshan Ahmed
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Abd Ullah
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Sikandar Ali
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanju Gao
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Josep Peñuelas
- CSIC, Global Ecology Unit, CREAF-CSIC-UAB, Bellaterra, 08193, Barcelona, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain
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Giraldo-Silva A, Masiello CA. Environmental conditions play a key role in controlling the composition and diversity of Colombian biocrust microbiomes. Front Microbiol 2024; 15:1236554. [PMID: 38725684 PMCID: PMC11081033 DOI: 10.3389/fmicb.2024.1236554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 03/11/2024] [Indexed: 05/12/2024] Open
Abstract
Drylands soils worldwide are naturally colonized by microbial communities known as biocrusts. These soil microbiomes render important ecosystem services associated with soil fertility, water holding capacity, and stability to the areas they cover. Because of the importance of biocrusts in the global cycling of nutrients, there is a growing interest in describing the many microbial configurations these communities display worldwide. However, comprehensive 16S rRNA genes surveys of biocrust communities do not exist for much of the planet: for example, in the continents of South America and the northern part of Africa. The absence of a global understanding of biocrust biodiversity has lead us to assign a general importance to community members that may, in fact, be regional. Here we report for the first time the presence of biocrusts in Colombia (South America) through 16S rRNA genes surveys across an arid, a semi-arid and a dry subtropical region within the country. Our results constitute the first glance of the Bacterial/Archaeal communities associated with South American biocrust microbiomes. Communities where cyanobacteria other than Microcoleus vaginatus prevail, despite the latter being considered a key species elsewhere, illustrate differentiable results in these surveys. We also find that the coastal biocrust communities in Colombia include halo-tolerant and halophilic species, and that niche preference of some nitrogen fixing organisms deviate from previously described global trends. In addition, we identified a high proportion (ranging from 5 to 70%, in average) of cyanobacterial sequences that did not match any formally described cyanobacterial species. Our investigation of Colombian biocrusts points to highly diverse communities with climatic regions controlling taxonomic configurations. They also highlight an extensive local diversity to be discovered which is central to better design management and restoration strategies for drylands soils currently undergoing disturbances due to land use and global warming. Finally, this field study highlights the need for an improved mechanistic understanding of the response of key biocrust community members to changes in moisture and temperature.
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Affiliation(s)
- Ana Giraldo-Silva
- Department of Science, Ecology Group and Institute for Multidisciplinary Research in Applied Biology, Public University of Navarre (UPNA), Pamplona, Spain
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, United States
| | - Caroline A. Masiello
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, United States
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Roncero-Ramos B, Savaglia V, Durieu B, Van de Vreken I, Richel A, Wilmotte A. Ecophysiological and genomic approaches to cyanobacterial hardening for restoration. JOURNAL OF PHYCOLOGY 2024; 60:465-482. [PMID: 38373045 DOI: 10.1111/jpy.13436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 12/15/2023] [Accepted: 12/15/2023] [Indexed: 02/20/2024]
Abstract
Cyanobacteria inhabit extreme environments, including drylands, providing multiple benefits to the ecosystem. Soil degradation in warm drylands is increasing due to land use intensification. Restoration methods adapted to the extreme stress in drylands are being developed, such as cyanobacteria inoculation to recover biocrusts. For this type of restoration method to be a success, it is crucial to optimize the survival of inoculated cyanobacteria in the field. One strategy is to harden them to be acclimated to stressful conditions after laboratory culturing. Here, we analyzed the genome and ecophysiological response to osmotic desiccation and UVR stresses of an Antarctic cyanobacterium, Stenomitos frigidus ULC029, which is closely related to other cyanobacteria from warm and cold dryland soils. Chlorophyll a concentrations showed that preculturing ULC029 under moderate osmotic stress improved its survival during an assay of desiccation plus rehydration under UVR. Additionally, its sequential exposure to these stress factors increased the production of exopolysaccharides, carotenoids, and scytonemin. Desiccation, but not osmotic stress, increased the concentrations of the osmoprotectants trehalose and sucrose. However, osmotic stress might induce the production of other osmoprotectants, for which the complete pathways were observed in the ULC029 genome. In total, 140 genes known to be involved in stress resistance were annotated. Here, we confirm that the sequential application of moderate osmotic stress and dehydration could improve cyanobacterial hardening for soil restoration by inducing several resistance mechanisms. We provide a high-quality genome of ULC029 and a description of the main resistance mechanisms (i.e., production of exopolysaccharides, osmoprotectants, chlorophyll, and carotenoids; DNA repair; and oxidative stress protection).
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Affiliation(s)
- Beatriz Roncero-Ramos
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Sevilla, Spain
| | - Valentina Savaglia
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Benoit Durieu
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
| | | | - Aurore Richel
- TERRA-Biomass and Green Technologies, University of Liège, Gembloux, Belgium
| | - Annick Wilmotte
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
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Liu Y, Jia R, Wang W, Wan Y, Gao Y, Zhan H, Ren J, Chen Z, Qiu F, Zhu J. Vascular plant communities and biocrusts act as controlling factors in mitigating soil erosion on the Great Wall in a semi-humid area of Northwestern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170515. [PMID: 38309344 DOI: 10.1016/j.scitotenv.2024.170515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 01/26/2024] [Accepted: 01/26/2024] [Indexed: 02/05/2024]
Abstract
The Great Wall, a World Heritage Site and a vertical wall habitat, is under threat of soil erosion. The role of vascular plants and biocrust in controlling soil erosion has attracted attention, yet our knowledge of the underlying mechanism is limited, and there is a lack of systematic strategies for erosion prevention and control. In this study, we quantified the vascular plant community functional composition (including species diversity, functional diversity, and community-weighted mean), biocrust coverage, and soil erosion levels associated with seven different zones (lower, middle, and upper zones on East and West faces, plus wall crest) of the Great Wall. We then employed a combination of linear regression analysis, random forest model, and structural equation model to evaluate the individual and combined effects, as well as the direction and relative importance of these factors in reducing soil erosion. The results indicated that the vascular plant species richness, species diversity, functional richness, community-weighted mean, and moss crust coverage decreased significantly from the crest to the lower zone of the Great Wall (P < 0.05), and were negatively correlated with the soil erosion area and depth on both sides of the Great Wall (P < 0.05). This suggests that higher zones on the wall favored the colonization and growth of biocrusts and vascular plants and that biocrusts and vascular plants reduced soil erosion on the wall. Based on these findings, we propose a "restoration framework" for managing soil erosion on walls, based on biocrust and vascular plant communities (namely target species selection, plant community construction, biocrust inoculation, and maintenance of community stability), which aims to address the urgent need for more effective soil erosion prevention and control strategies on the Great Wall and provide practical methods that practitioners can utilize.
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Affiliation(s)
- Yanping Liu
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rongliang Jia
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Wanfu Wang
- National Research Center for Conservation of Ancient Wall Paintings and Earthen Sites, Dunhuang Academy, Dunhuang, Gansu 736200, China; Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 73000, China.
| | - Yuchen Wan
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanhong Gao
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Hongtao Zhan
- National Research Center for Conservation of Ancient Wall Paintings and Earthen Sites, Dunhuang Academy, Dunhuang, Gansu 736200, China
| | - Jing Ren
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 73000, China
| | - Zhang Chen
- National Research Center for Conservation of Ancient Wall Paintings and Earthen Sites, Dunhuang Academy, Dunhuang, Gansu 736200, China
| | - Fei Qiu
- National Research Center for Conservation of Ancient Wall Paintings and Earthen Sites, Dunhuang Academy, Dunhuang, Gansu 736200, China
| | - Jing Zhu
- National Research Center for Conservation of Ancient Wall Paintings and Earthen Sites, Dunhuang Academy, Dunhuang, Gansu 736200, China
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Phillips ML, Lauria C, Spector T, Bradford JB, Gehring C, Osborne BB, Howell A, Grote EE, Rondeau RJ, Trimber GM, Robinson B, Reed SC. Trajectories and tipping points of piñon-juniper woodlands after fire and thinning. GLOBAL CHANGE BIOLOGY 2024; 30:e17149. [PMID: 38342970 DOI: 10.1111/gcb.17149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 02/13/2024]
Abstract
Piñon-juniper (PJ) woodlands are a dominant community type across the Intermountain West, comprising over a million acres and experiencing critical effects from increasing wildfire. Large PJ mortality and regeneration failure after catastrophic wildfire have elevated concerns about the long-term viability of PJ woodlands. Thinning is increasingly used to safeguard forests from fire and in an attempt to increase climate resilience. We have only a limited understanding of how fire and thinning will affect the structure and function of PJ ecosystems. Here, we examined vegetation structure, microclimate conditions, and PJ regeneration dynamics following ~20 years post-fire and thinning treatments. We found that burned areas had undergone a state shift that did not show signs of returning to their previous state. This shift was characterized by (1) distinct plant community composition dominated by grasses; (2) a lack of PJ recruitment; (3) a decrease in the sizes of interspaces in between plants; (4) lower abundance of late successional biological soil crusts; (5) lower mean and minimum daily soil moisture values; (6) lower minimum daily vapor pressure deficit; and (7) higher photosynthetically active radiation. Thinning created distinct plant communities and served as an intermediate between intact and burned communities. More intensive thinning decreased PJ recruitment and late successional biocrust cover. Our results indicate that fire has the potential to create drier and more stressful microsite conditions, and that, in the absence of active management following fire, there may be shifts to persistent ecological states dominated by grasses. Additionally, more intensive thinning had a larger impact on community structure and recruitment than less intensive thinning, suggesting that careful consideration of goals could help avoid unintended consequences. While our results indicate the vulnerability of PJ ecosystems to fire, they also highlight management actions that could be adapted to create conditions that promote PJ re-establishment.
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Affiliation(s)
- Michala L Phillips
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, Hawai'i Volcanoes National Park, Hawai'i, USA
| | - Cara Lauria
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Tova Spector
- U.S. Forest Service, Intermountain Region 4, Ogden, Utah, USA
| | - John B Bradford
- U.S. Geological Survey, Southwest Biological Science Center, Flagstaff, Arizona, USA
| | - Catherine Gehring
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Brooke B Osborne
- Department of Environment and Society, Utah State University, Moab, Utah, USA
| | - Armin Howell
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Edmund E Grote
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Renee J Rondeau
- Colorado State University, Colorado Natural Heritage Program, Hesperus, Colorado, USA
| | - Gillian M Trimber
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | | | - Sasha C Reed
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
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Abrantes GH, Gücker B, Chaves RC, Boëchat IG, Figueredo CC. Epilithic biofilms provide large amounts of nitrogen to tropical mountain landscapes. Environ Microbiol 2023; 25:3592-3603. [PMID: 37816630 DOI: 10.1111/1462-2920.16515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 09/19/2023] [Indexed: 10/12/2023]
Abstract
We show that epilithic biofilms are a relevant nitrogen (N) source in a rocky mountain range in Brazil. During different seasons, we quantified nitrate, ammonium, dissolved organic N (DON) and total dissolved N (TDN) leached by a simulated short rain event. We quantified the epilithic autotrophic biomass by taxonomic groups and its correlation with leached N. We hypothesized that leached N would be correlated to heterocystous cyanobacteria biomass since they are more efficient N2 fixers. We estimated a landscape N supply of 8.5 kg.ha-1 .year-1 considering the mean precipitation in the region. TDN in leachate was mainly composed of DON (83.8% ± 22%), followed by nitrate (12.1% ± 3%) and ammonium (5% ± 5%). The autotrophic epilithic community was mainly composed of non-heterocystous (Gloeocapsopsis) and heterocystous cyanobacteria (Scytonema and Stigonema), except for a site more commonly affected by fire events that showed a dominance of Chlorophyta. Biogeochemical upscaling was facilitated by the fact that N leaching was not different among sites or related to autotrophic epilithic biomass or assemblage composition. In conclusion, the capacity of epilithic biofilms to provide N to surrounding systems is an ecosystem service that underscores the necessity to conserve them and their habitats.
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Affiliation(s)
| | - Björn Gücker
- Department of Geosciences, Federal University of São João del-Rei, São João del-Rei, Brazil
| | - Ronaldo César Chaves
- Department of Botany, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Iola Gonçalves Boëchat
- Department of Geosciences, Federal University of São João del-Rei, São João del-Rei, Brazil
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9
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Brambilla M, Chiari G, Commisso M, Nerva L, Musetti R, Petraglia A, Degola F. Glutamate dehydrogenase in "Liverworld"-A study in selected species to explore a key enzyme of plant primary metabolism in Marchantiophyta. PHYSIOLOGIA PLANTARUM 2023; 175:e14071. [PMID: 38148220 DOI: 10.1111/ppl.14071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 12/28/2023]
Abstract
In plants, glutamate dehydrogenase (GDH) is an ubiquitous enzyme that catalyzes the reversible amination of 2-oxoglutarate in glutamate. It contributes to both the amino acid homeostasis and the management of intracellular ammonium, and it is regarded as a key player at the junction of carbon and nitrogen assimilation pathways. To date, information about the GDH of terrestrial plants refers to a very few species only. We focused on selected species belonging to the division Marchantiophyta, providing the first panoramic overview of biochemical and functional features of GDH in liverworts. Native electrophoretic analyses showed an isoenzymatic profile less complex than what was reported for Arabidposis thaliana and other angiosperms: the presence of a single isoform corresponding to an α-homohexamer, differently prone to thermal inactivation on a species- and organ-basis, was found. Sequence analysis conducted on amino acid sequences confirmed a high similarity of GDH in modern liverworts with the GDH2 protein of A. thaliana, strengthening the hypothesis that the duplication event that gave origin to GDH1-homolog gene from GDH2 occurred after the evolutionary bifurcation that separated bryophytes and tracheophytes. Experiments conducted on Marchantia polymorpha and Calypogeia fissa grown in vitro and compared to A. thaliana demonstrated through in gel activity detection and monodimensional Western Blot that the aminating activity of GDH resulted in strongly enhanced responses to ammonium excess in liverworts as well, even if at a different extent compared to Arabidopsis and other vascular species. The comparative analysis by bi-dimensional Western Blot suggested that the regulation of the enzyme could be, at least partially, untied from the protein post-translational pattern. Finally, immuno-electron microscopy revealed that the GDH enzyme localizes at the subcellular level in both mitochondria and chloroplasts of parenchyma and is specifically associated to the endomembrane system in liverworts.
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Affiliation(s)
- Martina Brambilla
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
| | - Giorgio Chiari
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
| | - Mauro Commisso
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Luca Nerva
- Council for Agricultural Research and Economics - Research Centre for Viticulture and Enology (CREA-VE), Conegliano, Italy
| | - Rita Musetti
- Department of Land, Environment, Agriculture and Forestry, University of Padova, Padova, Italy
| | - Alessandro Petraglia
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
| | - Francesca Degola
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
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10
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Abstract
Biological soil crusts are thin, inconspicuous communities along the soil atmosphere ecotone that, until recently, were unrecognized by ecologists and even more so by microbiologists. In its broadest meaning, the term biological soil crust (or biocrust) encompasses a variety of communities that develop on soil surfaces and are powered by photosynthetic primary producers other than higher plants: cyanobacteria, microalgae, and cryptogams like lichens and mosses. Arid land biocrusts are the most studied, but biocrusts also exist in other settings where plant development is constrained. The minimal requirement is that light impinge directly on the soil; this is impeded by the accumulation of plant litter where plants abound. Since scientists started paying attention, much has been learned about their microbial communities, their composition, ecological extent, and biogeochemical roles, about how they alter the physical behavior of soils, and even how they inform an understanding of early life on land. This has opened new avenues for ecological restoration and agriculture.
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Affiliation(s)
- Ferran Garcia-Pichel
- Center for Fundamental and Applied Microbiomics and School of Life Sciences, Arizona State University, Tempe, Arizona, USA;
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11
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Tang K, Liang Y, Yuan B, Meng J, Feng F. Spatial distribution and core community of diazotrophs in Biological soil crusts and subsoils in temperate semi-arid and arid deserts of China. Front Microbiol 2023; 14:1074855. [PMID: 37608942 PMCID: PMC10440438 DOI: 10.3389/fmicb.2023.1074855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 07/25/2023] [Indexed: 08/24/2023] Open
Abstract
Introduction Biological soil crusts (BSCs) are distributed in arid and semiarid regions, and they function as important microhabitats for nitrogen fixation. The diazotroph community is critical for nitrogen fixation in BSCs and their subsoils. However, little is known about the key groups in different types of BSCs and subsoils in temperate semi-arid or arid deserts. Methods Here, we sampled three types of BSCs and their subsoils from the Inner Mongolian plateau, investigated the distribution characteristics of the diazotroph community by high-throughput sequencing, predicted keystone species using the molecular ecological network analyses pipeline (MENAP), and verified their close relationship with the available nitrogen (AN) content. Results The results showed that available nitrogen content in BSCs was higher than that in subsoils in three different types of BSCs, and there were differences among seasons and according to the mean annual precipitation. The abundance of diazotrophs was higher in Cyano-BSCs, while diversity had no significant difference among BSCs and subsoils. Cyanobacteria and Proteobacteria, Nostocaceae and Scytonemataceae, Skermanella, Scytonema, Azohydromonas, Nostoc and Trichormus were the dominant phyla, families, and genera, respectively. The dominant groups belong to Skermanella, Scytonema, and Nostoc formed the core diazotroph community in the three types of BSCs and subsoils, and each had a close relationship with AN. Discussion These results indicate that diazotrophs in BSCs and subsoils had high diversity, and the core diazotroph communities have a close relationship with nitrogen fixation and that they may be the main contributor to nitrogen fixing in BSCs and subsoils in temperate deserts.
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Affiliation(s)
- Kai Tang
- Laboratory for Environmental Microbiology and Biotechnology in Arid and Cold Regions, College of Life Sciences, Inner Mongolia Agricultural University, Hohhot, China
| | - Yungang Liang
- Laboratory for Environmental Microbiology and Biotechnology in Arid and Cold Regions, College of Life Sciences, Inner Mongolia Agricultural University, Hohhot, China
| | - Bo Yuan
- Laboratory for Environmental Microbiology and Biotechnology in Arid and Cold Regions, College of Life Sciences, Inner Mongolia Agricultural University, Hohhot, China
- College of Life Science, Inner Mongolia Normal University, Hohhot, China
| | - Jianyu Meng
- Laboratory for Environmental Microbiology and Biotechnology in Arid and Cold Regions, College of Life Sciences, Inner Mongolia Agricultural University, Hohhot, China
| | - Fuying Feng
- Laboratory for Environmental Microbiology and Biotechnology in Arid and Cold Regions, College of Life Sciences, Inner Mongolia Agricultural University, Hohhot, China
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12
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Trexler RV, Van Goethem MW, Goudeau D, Nath N, Malmstrom RR, Northen TR, Couradeau E. BONCAT-FACS-Seq reveals the active fraction of a biocrust community undergoing a wet-up event. Front Microbiol 2023; 14:1176751. [PMID: 37434715 PMCID: PMC10330726 DOI: 10.3389/fmicb.2023.1176751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/05/2023] [Indexed: 07/13/2023] Open
Abstract
Determining which microorganisms are active within soil communities remains a major technical endeavor in microbial ecology research. One promising method to accomplish this is coupling bioorthogonal non-canonical amino acid tagging (BONCAT) with fluorescence activated cell sorting (FACS) which sorts cells based on whether or not they are producing new proteins. Combined with shotgun metagenomic sequencing (Seq), we apply this method to profile the diversity and potential functional capabilities of both active and inactive microorganisms in a biocrust community after being resuscitated by a simulated rain event. We find that BONCAT-FACS-Seq is capable of discerning the pools of active and inactive microorganisms, especially within hours of applying the BONCAT probe. The active and inactive components of the biocrust community differed in species richness and composition at both 4 and 21 h after the wetting event. The active fraction of the biocrust community is marked by taxa commonly observed in other biocrust communities, many of which play important roles in species interactions and nutrient transformations. Among these, 11 families within the Firmicutes are enriched in the active fraction, supporting previous reports indicating that the Firmicutes are key early responders to biocrust wetting. We highlight the apparent inactivity of many Actinobacteria and Proteobacteria through 21 h after wetting, and note that members of the Chitinophagaceae, enriched in the active fraction, may play important ecological roles following wetting. Based on the enrichment of COGs in the active fraction, predation by phage and other bacterial members, as well as scavenging and recycling of labile nutrients, appear to be important ecological processes soon after wetting. To our knowledge, this is the first time BONCAT-FACS-Seq has been applied to biocrust samples, and therefore we discuss the potential advantages and shortcomings of coupling metagenomics to BONCAT to intact soil communities such as biocrust. In all, by pairing BONCAT-FACS and metagenomics, we are capable of highlighting the taxa and potential functions that typifies the microbes actively responding to a rain event.
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Affiliation(s)
- Ryan V. Trexler
- Intercollege Graduate Degree Program in Ecology, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Marc W. Van Goethem
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Danielle Goudeau
- Lawrence Berkeley National Laboratory, DOE Joint Genome Institute, Berkeley, CA, United States
| | - Nandita Nath
- Lawrence Berkeley National Laboratory, DOE Joint Genome Institute, Berkeley, CA, United States
| | - Rex R. Malmstrom
- Lawrence Berkeley National Laboratory, DOE Joint Genome Institute, Berkeley, CA, United States
| | - Trent R. Northen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Lawrence Berkeley National Laboratory, DOE Joint Genome Institute, Berkeley, CA, United States
| | - Estelle Couradeau
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, United States
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13
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Finger-Higgens R, Bishop TBB, Belnap J, Geiger EL, Grote EE, Hoover DL, Reed SC, Duniway MC. Droughting a megadrought: Ecological consequences of a decade of experimental drought atop aridification on the Colorado Plateau. GLOBAL CHANGE BIOLOGY 2023; 29:3364-3377. [PMID: 36919684 DOI: 10.1111/gcb.16681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/20/2023] [Indexed: 05/16/2023]
Abstract
Global dryland vegetation communities will likely change as ongoing drought conditions shift regional climates towards a more arid future. Additional aridification of drylands can impact plant and ground cover, biogeochemical cycles, and plant-soil feedbacks, yet how and when these crucial ecosystem components will respond to drought intensification requires further investigation. Using a long-term precipitation reduction experiment (35% reduction) conducted across the Colorado Plateau and spanning 10 years into a 20+ year regional megadrought, we explored how vegetation cover, soil conditions, and growing season nitrogen (N) availability are impacted by drying climate conditions. We observed large declines for all dominant plant functional types (C3 and C4 grasses and C3 and C4 shrubs) across measurement period, both in the drought treatment and control plots, likely due to ongoing regional megadrought conditions. In experimental drought plots, we observed less plant cover, less biological soil crust cover, warmer and drier soil conditions, and more soil resin-extractable N compared to the control plots. Observed increases in soil N availability were best explained by a negative correlation with plant cover regardless of treatment, suggesting that declines in vegetation N uptake may be driving increases in available soil N. However, in ecosystems experiencing long-term aridification, increased N availability may ultimately result in N losses if soil moisture is consistently too dry to support plant and microbial N immobilization and ecosystem recovery. These results show dramatic, worrisome declines in plant cover with long-term drought. Additionally, this study highlights that more plant cover losses are possible with further drought intensification and underscore that, in addition to large drought effects on aboveground communities, drying trends drive significant changes to critical soil resources such as N availability, all of which could have long-term ecosystem impacts for drylands.
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Affiliation(s)
| | - Tara B B Bishop
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Jayne Belnap
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Erika L Geiger
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Edmund E Grote
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - David L Hoover
- USDA-ARS Rangeland Resource and Systems Research Unit, Crops Research Laboratory, Fort Collins, Colorado, USA
| | - Sasha C Reed
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Michael C Duniway
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
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14
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Cleveland CC, Reis CRG, Perakis SS, Dynarski KA, Batterman SA, Crews TE, Gei M, Gundale MJ, Menge DNL, Peoples MB, Reed SC, Salmon VG, Soper FM, Taylor BN, Turner MG, Wurzburger N. Exploring the Role of Cryptic Nitrogen Fixers in Terrestrial Ecosystems: A Frontier in Nitrogen Cycling Research. Ecosystems 2022. [DOI: 10.1007/s10021-022-00804-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Richardson AD, Kong GV, Taylor KM, Le Moine JM, Bowker MA, Barber JJ, Basler D, Carbone MS, Hayer M, Koch GW, Salvatore MR, Sonnemaker AW, Trilling DE. Soil-atmosphere fluxes of CO2, CH4, and N2O across an experimentally-grown, successional gradient of biocrust community types. Front Microbiol 2022; 13:979825. [PMID: 36225383 PMCID: PMC9549369 DOI: 10.3389/fmicb.2022.979825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/07/2022] [Indexed: 11/13/2022] Open
Abstract
Biological soil crusts (biocrusts) are critical components of dryland and other ecosystems worldwide, and are increasingly recognized as novel model ecosystems from which more general principles of ecology can be elucidated. Biocrusts are often diverse communities, comprised of both eukaryotic and prokaryotic organisms with a range of metabolic lifestyles that enable the fixation of atmospheric carbon and nitrogen. However, how the function of these biocrust communities varies with succession is incompletely characterized, especially in comparison to more familiar terrestrial ecosystem types such as forests. We conducted a greenhouse experiment to investigate how community composition and soil-atmosphere trace gas fluxes of CO2, CH4, and N2O varied from early-successional light cyanobacterial biocrusts to mid-successional dark cyanobacteria biocrusts and late-successional moss-lichen biocrusts and as biocrusts of each successional stage matured. Cover type richness increased as biocrusts developed, and richness was generally highest in the late-successional moss-lichen biocrusts. Microbial community composition varied in relation to successional stage, but microbial diversity did not differ significantly among stages. Net photosynthetic uptake of CO2 by each biocrust type also increased as biocrusts developed but tended to be moderately greater (by up to ≈25%) for the mid-successional dark cyanobacteria biocrusts than the light cyanobacterial biocrusts or the moss-lichen biocrusts. Rates of soil C accumulation were highest for the dark cyanobacteria biocrusts and light cyanobacteria biocrusts, and lowest for the moss-lichen biocrusts and bare soil controls. Biocrust CH4 and N2O fluxes were not consistently distinguishable from the same fluxes measured from bare soil controls; the measured rates were also substantially lower than have been reported in previous biocrust studies. Our experiment, which uniquely used greenhouse-grown biocrusts to manipulate community composition and accelerate biocrust development, shows how biocrust function varies along a dynamic gradient of biocrust successional stages.
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Affiliation(s)
- Andrew D. Richardson
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, United States
- *Correspondence: Andrew D. Richardson,
| | - Gary V. Kong
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
- University of California, Santa Barbara, CA, United States
| | - Katrina M. Taylor
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
- Department of Astronomy and Astrophysics, The Pennsylvania State University, State College, PA, United States
| | - James M. Le Moine
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, United States
| | - Matthew A. Bowker
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
- School of Forestry, Northern Arizona University, Flagstaff, AZ, United States
| | - Jarrett J. Barber
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, United States
| | - David Basler
- Department of Environmental Sciences–Botany, University of Basel, Basel, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Mariah S. Carbone
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - George W. Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - Mark R. Salvatore
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
| | - A. Wesley Sonnemaker
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
- Lowell Observatory, Flagstaff, AZ, United States
| | - David E. Trilling
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
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16
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Kratz AM, Maier S, Weber J, Kim M, Mele G, Gargiulo L, Leifke AL, Prass M, Abed RMM, Cheng Y, Su H, Pöschl U, Weber B. Reactive Nitrogen Hotspots Related to Microscale Heterogeneity in Biological Soil Crusts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11865-11877. [PMID: 35929951 PMCID: PMC9387110 DOI: 10.1021/acs.est.2c02207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/12/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Biocrusts covering drylands account for major fractions of terrestrial biological nitrogen fixation and release large amounts of gaseous reactive nitrogen (Nr) as nitrous acid (HONO) and nitric oxide (NO). Recent investigations suggested that aerobic and anaerobic microbial nitrogen transformations occur simultaneously upon desiccation of biocrusts, but the spatio-temporal distribution of seemingly contradictory processes remained unclear. Here, we explore small-scale gradients in chemical concentrations related to structural characteristics and organism distribution. X-ray microtomography and fluorescence microscopy revealed mixed pore size structures, where photoautotrophs and cyanobacterial polysaccharides clustered irregularly in the uppermost millimeter. Microsensor measurements showed strong gradients of pH, oxygen, and nitrite, nitrate, and ammonium ion concentrations at micrometer scales in both vertical and lateral directions. Initial oxygen saturation was mostly low (∼30%) at full water holding capacity, suggesting widely anoxic conditions, and increased rapidly upon desiccation. Nitrite concentrations (∼6 to 800 μM) and pH values (∼6.5 to 9.5) were highest around 70% WHC. During further desiccation they decreased, while emissions of HONO and NO increased, reaching maximum values around 20% WHC. Our results illustrate simultaneous, spatially separated aerobic and anaerobic nitrogen transformations, which are critical for Nr emissions, but might be impacted by future global change and land management.
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Affiliation(s)
- Alexandra Maria Kratz
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
| | - Stefanie Maier
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
- Institute
of Biology, Division of Plant Sciences, University of Graz, Graz 8010, Austria
| | - Jens Weber
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
- Institute
of Biology, Division of Plant Sciences, University of Graz, Graz 8010, Austria
| | - Minsu Kim
- Institute
of Biology, Division of Plant Sciences, University of Graz, Graz 8010, Austria
| | - Giacomo Mele
- Institute
for Agriculture and Forestry in the Mediterranean, National Council of Research, 80055 Portici, Italy
| | - Laura Gargiulo
- Institute
for Agriculture and Forestry in the Mediterranean, National Council of Research, 80055 Portici, Italy
| | - Anna Lena Leifke
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
| | - Maria Prass
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
| | - Raeid M. M. Abed
- College
of Science, Biology Department, Sultan Qaboos
University, P.O. Box 36, Al Khoud, Seeb 123, Sultanate of Oman
| | - Yafang Cheng
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
| | - Hang Su
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
| | - Ulrich Pöschl
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
| | - Bettina Weber
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, Mainz 55128, Germany
- Institute
of Biology, Division of Plant Sciences, University of Graz, Graz 8010, Austria
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17
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Rong X, Zhou X, Li X, Yao M, Lu Y, Xu P, Yin B, Li Y, Aanderud ZT, Zhang Y. Biocrust diazotrophs and bacteria rather than fungi are sensitive to chronic low N deposition. Environ Microbiol 2022; 24:5450-5466. [PMID: 35844197 DOI: 10.1111/1462-2920.16095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 06/03/2022] [Indexed: 11/03/2022]
Abstract
Anthropogenic long-term nitrogen (N) deposition may dramatically impact biocrusts due to the overarching N limitation of soil biota in deserts. Even low levels of N may reach a critical loading threshold altering biocrust constituents and function. To identify the impact of chronic and continuous low levels of N deposition on biocrusts, we created a realistic gradient mirroring anthropogenic N addition rate (2:1 NH4 + : NO3 - rates: 0.3, 0.5, 1.0, 1.5, 3 g N m-2 yr-1 ) and measured the response of bacteria and fungi within cyanobacterial-dominated biocrusts over 8 years in a temperate desert, the Gurbantunggut Desert, China. We found that once N deposition reached 1.5 g N m-2 yr-1 biocrust bacterial communities, including diazotrophs, were altered while no such tipping point existed for fungi. Above the threshold, bacterial richness was enhanced, the relative abundance of Chloroflexi, FBP and Gemmatimonadetes was elevated, and diazotrophs shifted from being dominated by Nostocaceae and Scytonemataceae (Cyanobacteria) to free-living Bradyrhizobiaceae (Alphaproteobacteria). Alternatively, the relative recovery of a few fungal species within the Lecanorales, Pleosporales and Verrucariales became either enriched or diminished due to N deposition. The chronic addition of N resulted in a dense and interconnected bacterial co-occurrence network that accentuated a functional shift from networks dominated by phototrophic species within the Nostocaceae, Xenococcaceae, Phormidiaceae and Scytonemataceae (Cyanobacteria) to ammonia-oxidizing species within the Nitrosomonadaceae (Betaproteobacteria) and nitrifying bacteria [i.e. Nitrospiraceae (Nitrospirae)]. Based on structural equation models, the effects of N additions on biocrust constituents were imposed through indirect effects on pH, soil electrical conductivity and ammonium concentrations. In summary, biocrust constituents are generally insensitive to chronic low levels of N depositions until rates reach above 1.5 g N m-2 yr-1 with diazotrophs being the most sensitive biocrust constituents followed by bacteria and finally fungi. Ultimately once the threshold is reached N deposition favours biocrust constituents utilizing inorganic N and other C sources over relying on phototrophic and/or N-fixing cyanobacteria for C and N.
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Affiliation(s)
- Xiaoying Rong
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Xiaobing Zhou
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Xiangzhen Li
- Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Minjie Yao
- College of Resources and Environment, Fujian Agriculture and Forest University, Fuzhou, China
| | - Yongxing Lu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Peng Xu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Benfeng Yin
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Yonggang Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Zachary T Aanderud
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, USA
| | - Yuanming Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
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18
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Ladrón de Guevara M, Maestre FT. Ecology and responses to climate change of biocrust-forming mosses in drylands. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4380-4395. [PMID: 35553672 PMCID: PMC9291340 DOI: 10.1093/jxb/erac183] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Interest in understanding the role of biocrusts as ecosystem engineers in drylands has substantially increased during the past two decades. Mosses are a major component of biocrusts and dominate their late successional stages. In general, their impacts on most ecosystem functions are greater than those of early-stage biocrust constituents. However, it is common to find contradictory results regarding how moss interactions with different biotic and abiotic factors affect ecosystem processes. This review aims to (i) describe the adaptations and environmental constraints of biocrust-forming mosses in drylands, (ii) identify their primary ecological roles in these ecosystems, and (iii) synthesize their responses to climate change. We emphasize the importance of interactions between specific functional traits of mosses (e.g. height, radiation reflectance, morphology, and shoot densities) and both the environment (e.g. climate, topography, and soil properties) and other organisms to understand their ecological roles and responses to climate change. We also highlight key areas that should be researched in the future to fill essential gaps in our understanding of the ecology and the responses to ongoing climate change of biocrust-forming mosses. These include a better understanding of intra- and interspecific interactions and mechanisms driving mosses' carbon balance during desiccation-rehydration cycles.
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19
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Oliveira MF, Maciel-Silva AS. Biological soil crusts and how they might colonize other worlds: insights from these Brazilian ecosystem engineers. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4362-4379. [PMID: 35522077 DOI: 10.1093/jxb/erac162] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 04/17/2022] [Indexed: 06/14/2023]
Abstract
When bryophytes, lichens, eukaryotic algae, cyanobacteria, bacteria, and fungi live interacting intimately with the most superficial particles of the soil, they form a complex community of organisms called the biological soil crust (BSC or biocrust). These biocrusts occur predominantly in drylands, where they provide important ecological services such as soil aggregation, moisture retention, and nitrogen fixation. Unfortunately, many BSC communities remain poorly explored, especially in the tropics. This review summarizes studies about BSCs in Brazil, a tropical megadiverse country, and shows the importance of ecological, physiological, and taxonomic knowledge of biocrusts. We also compare Brazilian BSC communities with others around the world, describe why BSCs can be considered ecosystem engineers, and propose their use in the colonization of other worlds.
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Affiliation(s)
- Mateus Fernandes Oliveira
- Universidade Federal de Minas Gerais, Laboratório de Sistemática Vegetal, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - Adaíses Simone Maciel-Silva
- Universidade Federal de Minas Gerais, Laboratório de Sistemática Vegetal, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil
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20
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Drahorad S, Felix‐Henningsen P, Siemens J, Marschner B, Heinze S. Patterns of enzyme activities and nutrient availability within biocrusts under increasing aridity in Negev desert. Ecosphere 2022. [DOI: 10.1002/ecs2.4051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Sylvie Drahorad
- Institute for Soil Science and Soil Conservation, Research Centre for Biosystems Landuse and Nutrition (IFZ), Justus‐Liebig‐University Giessen Giessen Germany
| | - Peter Felix‐Henningsen
- Institute for Soil Science and Soil Conservation, Research Centre for Biosystems Landuse and Nutrition (IFZ), Justus‐Liebig‐University Giessen Giessen Germany
| | - Jan Siemens
- Institute for Soil Science and Soil Conservation, Research Centre for Biosystems Landuse and Nutrition (IFZ), Justus‐Liebig‐University Giessen Giessen Germany
| | - Bernd Marschner
- Department of Geography, Soil Science and Soil Ecology Ruhr‐Universität Bochum Bochum Germany
| | - Stefanie Heinze
- Department of Geography, Soil Science and Soil Ecology Ruhr‐Universität Bochum Bochum Germany
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21
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Weber B, Belnap J, Büdel B, Antoninka AJ, Barger NN, Chaudhary VB, Darrouzet-Nardi A, Eldridge DJ, Faist AM, Ferrenberg S, Havrilla CA, Huber-Sannwald E, Malam Issa O, Maestre FT, Reed SC, Rodriguez-Caballero E, Tucker C, Young KE, Zhang Y, Zhao Y, Zhou X, Bowker MA. What is a biocrust? A refined, contemporary definition for a broadening research community. Biol Rev Camb Philos Soc 2022; 97:1768-1785. [PMID: 35584903 PMCID: PMC9545944 DOI: 10.1111/brv.12862] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/10/2022] [Accepted: 04/12/2022] [Indexed: 12/22/2022]
Abstract
Studies of biological soil crusts (biocrusts) have proliferated over the last few decades. The biocrust literature has broadened, with more studies assessing and describing the function of a variety of biocrust communities in a broad range of biomes and habitats and across a large spectrum of disciplines, and also by the incorporation of biocrusts into global perspectives and biogeochemical models. As the number of biocrust researchers increases, along with the scope of soil communities defined as ‘biocrust’, it is worth asking whether we all share a clear, universal, and fully articulated definition of what constitutes a biocrust. In this review, we synthesize the literature with the views of new and experienced biocrust researchers, to provide a refined and fully elaborated definition of biocrusts. In doing so, we illustrate the ecological relevance and ecosystem services provided by them. We demonstrate that biocrusts are defined by four distinct elements: physical structure, functional characteristics, habitat, and taxonomic composition. We describe outgroups, which have some, but not all, of the characteristics necessary to be fully consistent with our definition and thus would not be considered biocrusts. We also summarize the wide variety of different types of communities that fall under our definition of biocrusts, in the process of highlighting their global distribution. Finally, we suggest the universal use of the Belnap, Büdel & Lange definition, with minor modifications: Biological soil crusts (biocrusts) result from an intimate association between soil particles and differing proportions of photoautotrophic (e.g. cyanobacteria, algae, lichens, bryophytes) and heterotrophic (e.g. bacteria, fungi, archaea) organisms, which live within, or immediately on top of, the uppermost millimetres of soil. Soil particles are aggregated through the presence and activity of these often extremotolerant biota that desiccate regularly, and the resultant living crust covers the surface of the ground as a coherent layer. With this detailed definition of biocrusts, illustrating their ecological functions and widespread distribution, we hope to stimulate interest in biocrust research and inform various stakeholders (e.g. land managers, land users) on their overall importance to ecosystem and Earth system functioning.
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Affiliation(s)
- Bettina Weber
- Division of Plant Sciences, Institute for Biology, University of Graz, Holteigasse 6, 8010, Graz, Austria.,Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany
| | - Jayne Belnap
- Southwest Biological Science Center, U.S. Geological Survey, 2290 S. Resource Blvd, Moab, UT, 84532, USA
| | - Burkhard Büdel
- Biology Institute, University of Kaiserslautern, PO Box 3049, 67653, Kaiserslautern, Germany
| | - Anita J Antoninka
- School of Forestry, Northern Arizona University, 200 E. Pine Knoll Drive, Box 15018, Flagstaff, AZ, 86011, USA
| | - Nichole N Barger
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Campus Box 334, Boulder, CO, 80309, USA
| | - V Bala Chaudhary
- Department of Environmental Studies, Dartmouth College, 6182 Steele Hall, 39 College Street, Hanover, NH, 03755, USA
| | - Anthony Darrouzet-Nardi
- Department of Biological Sciences, University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA
| | - David J Eldridge
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Akasha M Faist
- Department of Animal and Range Sciences, New Mexico State University, PO Box 30003, MSC 3-I, Las Cruces, NM, 88003, USA
| | - Scott Ferrenberg
- Department of Biology, New Mexico State University, PO Box 30001, MSC 3AF, Las Cruces, NM, 88003, USA
| | - Caroline A Havrilla
- Department of Forest and Rangeland Stewardship, Colorado State University, 1472 Campus Delivery, Colorado State University, Fort Collins, CO, 80521, USA
| | - Elisabeth Huber-Sannwald
- Division of Environmental Sciences, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Col. 4ta Sección, CP 78216, San Luis Potosi, SLP, Mexico
| | - Oumarou Malam Issa
- Institute of Ecology and Environmental Sciences of Paris (IEES-Paris), SU/IRD/CNRS/INRAE/UPEC, 32, Avenue Henry Varagnat, F-93143, Bondy Cedex, France
| | - Fernando T Maestre
- Instituto Multidisciplinar para el Estudio del Medio "Ramón Margalef", Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, 03690, San Vicente del Raspeig, Spain.,Departamento de Ecología, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, 03690, San Vicente del Raspeig, Spain
| | - Sasha C Reed
- Southwest Biological Science Center, U.S. Geological Survey, 2290 S. Resource Blvd, Moab, UT, 84532, USA
| | - Emilio Rodriguez-Caballero
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany.,Department of Agronomy and Centro de Investigación de Colecciones Científicas (CECOUAL), Universidad de Almería, carretera Sacramento s/n, 04120, La cañada de San Urbano, Almeria, Spain
| | - Colin Tucker
- USDA Forest Service, Northern Research Station, 410 MacInnes Drive, Houghton, MI, 49931-1134, USA
| | - Kristina E Young
- Extension Agriculture and Natural Resources, Utah State University, 1850 S. Aggie Blvd, Moab, UT, 84532, USA
| | - Yuanming Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Bejing Road, Urumqi City, 830011, Xinjiang, China
| | - Yunge Zhao
- Institute of Soil and Water Conservation, Northwest A & F University, 26 Xinong Road, Yangling, Shaanxi, 712100, China
| | - Xiaobing Zhou
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Bejing Road, Urumqi City, 830011, Xinjiang, China
| | - Matthew A Bowker
- School of Forestry, Northern Arizona University, 200 E. Pine Knoll Drive, Box 15018, Flagstaff, AZ, 86011, USA
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22
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Decline in biological soil crust N-fixing lichens linked to increasing summertime temperatures. Proc Natl Acad Sci U S A 2022; 119:e2120975119. [PMID: 35412916 PMCID: PMC9169860 DOI: 10.1073/pnas.2120975119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Across many global drylands, biocrusts form a protective barrier on the soil surface and fill many critical roles in these harsh yet fragile environments. Previous short-term research suggests that climate change and invasive plant introduction can damage and alter biocrust communities, yet few long-term observations exist. Using a globally unique long-term record of continuous biocrust surveys from a rare never-grazed, protected grassland on the US Colorado Plateau, we found lichen species diversity and cover to be negatively correlated with increasing summer air temperatures, while moss species showed more sensitivity to variation in precipitation and invasive grass cover. These results suggest that dryland systems may be at a critical tipping point where ongoing warming could result in biological soil crust degradation. Biological soil crusts (biocrusts), comprised of mosses, lichens, and cyanobacteria, are key components to many dryland communities. Climate change and other anthropogenic disturbances are thought to cause a decline in mosses and lichens, yet few long-term studies exist to track potential shifts in these sensitive soil-surface communities. Using a unique long-term observational dataset from a temperate dryland with initial observations dating back to 1967, we examine the effects of 53 y of observed environmental variation and Bromus tectorum invasion on biocrust communities in a grassland never grazed by domestic livestock. Annual observations show a steep decline in N-fixing lichen cover (dominated by Collema species) from 1996 to 2002, coinciding with a period of extended drought, with Collema communities never able to recover. Declines in other lichen species were also observed, both in number of species present and by total cover, which were attributed to increasing summertime temperatures. Conversely, moss species gradually gained in cover over the survey years, especially following a large Bromus tectorum invasion at the study onset (ca. 1996 to 2001). These results support a growing body of studies that suggests climate change is a key driver in changes to certain components of late-successional biocrust communities. Results here suggest that warming may partially negate decades of protection from disturbance, with biocrust communities reaching a vital tipping point. The accelerated rate of ongoing warming observed in this study may have resulted in the loss of lichen cover and diversity, which could have long-term implications for global temperate dryland ecosystems.
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23
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Abstract
Arid ecosystems cover ∼40% of the Earth's terrestrial surface and store a high proportion of the global nitrogen (N) pool. They are low-productivity, low-biomass, and polyextreme ecosystems, i.e., with (hyper)arid and (hyper)oligotrophic conditions and high surface UV irradiation and evapotranspiration. These polyextreme conditions severely limit the presence of macrofauna and -flora and, particularly, the growth and productivity of plant species. Therefore, it is generally recognized that much of the primary production (including N-input processes) and nutrient biogeochemical cycling (particularly N cycling) in these ecosystems are microbially mediated. Consequently, we present a comprehensive survey of the current state of knowledge of biotic and abiotic N-cycling processes of edaphic (i.e., open soil, biological soil crust, or plant-associated rhizosphere and rhizosheath) and hypo/endolithic refuge niches from drylands in general, including hot, cold, and polar desert ecosystems. We particularly focused on the microbially mediated biological nitrogen fixation, N mineralization, assimilatory and dissimilatory nitrate reduction, and nitrification N-input processes and the denitrification and anaerobic ammonium oxidation (anammox) N-loss processes. We note that the application of modern meta-omics and related methods has generated comprehensive data sets on the abundance, diversity, and ecology of the different N-cycling microbial guilds. However, it is worth mentioning that microbial N-cycling data from important deserts (e.g., Sahara) and quantitative rate data on N transformation processes from various desert niches are lacking or sparse. Filling this knowledge gap is particularly important, as climate change models often lack data on microbial activity and environmental microbial N-cycling communities can be key actors of climate change by producing or consuming nitrous oxide (N2O), a potent greenhouse gas.
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24
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Mallen‐Cooper M, Cornwell WK. Tissue chemistry of biocrust species along an aridity gradient and comparison to vascular plant leaves. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Max Mallen‐Cooper
- Ecology and Evolution Research Centre School of Biological, Earth and Environmental Sciences University of New South Wales Sydney New South Wales Australia
- Centre for Ecosystem Science School of Biological, Earth and Environmental Sciences University of New South Wales Sydney New South Wales Australia
| | - William K. Cornwell
- Ecology and Evolution Research Centre School of Biological, Earth and Environmental Sciences University of New South Wales Sydney New South Wales Australia
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25
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Young KE, Reed SC, Ferrenberg S, Faist A, Winkler DE, Cort C, Darrouzet-Nardi A. Incorporating Biogeochemistry into Dryland Restoration. Bioscience 2021; 71:907-917. [PMID: 34483747 DOI: 10.1093/biosci/biab043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dryland degradation is a persistent and accelerating global problem. Although the mechanisms initiating and maintaining dryland degradation are largely understood, returning productivity and function through ecological restoration remains difficult. Water limitation commonly drives slow recovery rates within drylands; however, the altered biogeochemical cycles that accompany degradation also play key roles in limiting restoration outcomes. Addressing biogeochemical changes and resource limitations may help improve restoration efforts within this difficult-to-restore biome. In the present article, we present a synthesis of restoration literature that identifies multiple ways biogeochemical understandings might augment dryland restoration outcomes, including timing restoration around resource cycling and uptake, connecting heterogeneous landscapes, manipulating resource pools, and using organismal functional traits to a restoration advantage. We conclude by suggesting ways to incorporate biogeochemistry into existing restoration frameworks and discuss research directions that may help improve restoration outcomes in the world's highly altered dryland landscapes.
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Affiliation(s)
- Kristina E Young
- Department of Biological Sciences, University of Texas, El Paso, El Paso, Texas, United States
| | - Sasha C Reed
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, United States
| | - Scott Ferrenberg
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States
| | - Akasha Faist
- Department of Animal and Range Sciences, New Mexico State University, Las Cruces, New Mexico, United States
| | - Daniel E Winkler
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, United States
| | - Catherine Cort
- Department of Biological Sciences, University of Texas, El Paso, El Paso, Texas, United States
| | - Anthony Darrouzet-Nardi
- Department of Biological Sciences, University of Texas, El Paso, El Paso, Texas, United States
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26
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Beneficial cyanosphere heterotrophs accelerate establishment of cyanobacterial biocrust. Appl Environ Microbiol 2021; 87:e0123621. [PMID: 34379492 DOI: 10.1128/aem.01236-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biological soil crusts (biocrusts) are communities of microbes that inhabit the surface of arid soils and provide essential services to dryland ecosystems. While resistant to extreme environmental conditions, biocrusts are susceptible to anthropogenic disturbances that can deprive ecosystems of these valuable services for decades. Until recently, culture-based efforts to produce inoculum for cyanobacterial biocrust restoration in the Southwestern US focused on producing and inoculating the most abundant primary producers and biocrust pioneers, Microcoleus vaginatus and members of the family Coleofasciculaceae (aka "Microcoleus streenstrupii complex"). The discovery that a unique microbial community characterized by diazotrophs is intimately associated with M. vaginatus, known as the "cyanosphere", suggests a symbiotic division of labor in which nutrients are traded between phototrophs and heterotrophs. To probe the potential use of such cyanosphere members in the restoration of biocrusts, we performed co-inoculations of soil substrates with cyanosphere constituents. This resulted in more rapid cyanobacterial growth over inoculations with the cyanobacterium alone. Additionally, we found that the mere addition of beneficial heterotrophs enhanced the formation of a cohesive biocrust without the need of additional phototrophic biomass within native soils that contain trace amounts of biocrust cyanobacteria. Our findings support the hitherto unknown role of beneficial heterotrophic bacteria in the establishment and growth of biocrusts and allow us to make recommendations concerning biocrust restoration efforts based on the presence of remnant biocrust communities in disturbed areas. Future biocrust restoration efforts should consider cyanobacteria and their beneficial heterotrophic community as inoculants. Importance The advancement of biocrust restoration methodologies for cyanobacterial biocrusts has been largely achieved through trial and error. Successes and failures could not always be traced back to particular factors. The investigation and application of foundational microbial interactions existing within biocrust communities is a crucial step toward informed and repeatable biocrust restoration methodologies.
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27
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Snail Mucus Increases the CO2 Efflux of Biological Soil Crusts. Ecosystems 2021. [DOI: 10.1007/s10021-021-00670-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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28
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Slate ML, McLeod ML, Callaway RM. Positive interactions between an exotic invader and moss biocrusts vary across life stage and correspond with the effect of water pulses on soil nitrogen. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13831] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Mandy L. Slate
- Division of Biological Sciences and the Institute on Ecosystems University of Montana Missoula MT USA
| | | | - Ragan M. Callaway
- Division of Biological Sciences and the Institute on Ecosystems University of Montana Missoula MT USA
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29
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You Y, Aho K, Lohse KA, Schwabedissen SG, Ledbetter RN, Magnuson TS. Biological Soil Crust Bacterial Communities Vary Along Climatic and Shrub Cover Gradients Within a Sagebrush Steppe Ecosystem. Front Microbiol 2021; 12:569791. [PMID: 34025590 PMCID: PMC8134670 DOI: 10.3389/fmicb.2021.569791] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 04/13/2021] [Indexed: 11/19/2022] Open
Abstract
Numerous studies have examined bacterial communities in biological soil crusts (BSCs) associated with warm arid to semiarid ecosystems. Few, however, have examined bacterial communities in BSCs associated with cold steppe ecosystems, which often span a wide range of climate conditions and are sensitive to trends predicted by relevant climate models. Here, we utilized Illumina sequencing to examine BSC bacterial communities with respect to climatic gradients (elevation), land management practices (grazing vs. non-grazing), and shrub/intershrub patches in a cold sagebrush steppe ecosystem in southwestern Idaho, United States. Particular attention was paid to shifts in bacterial community structure and composition. BSC bacterial communities, including keystone N-fixing taxa, shifted dramatically with both elevation and shrub-canopy microclimates within elevational zones. BSC cover and BSC cyanobacteria abundance were much higher at lower elevation (warmer and drier) sites and in intershrub areas. Shrub-understory BSCs were significantly associated with several non-cyanobacteria diazotrophic genera, including Mesorhizobium and Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium. High elevation (wetter and colder) sites had distinct, highly diverse, but low-cover BSC communities that were significantly indicated by non-cyanobacterial diazotrophic taxa including families in the order Rhizobiales and the family Frankiaceae. Abiotic soil characteristics, especially pH and ammonium, varied with both elevation and shrub/intershrub level, and were strongly associated with BSC community composition. Functional inference using the PICRUSt pipeline identified shifts in putative N-fixing taxa with respect to both the elevational gradient and the presence/absence of shrub canopy cover. These results add to current understanding of biocrust microbial ecology in cold steppe, serving as a baseline for future mechanistic research.
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30
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Wang Q, Han Y, Lan S, Hu C. Metagenomic Insight Into Patterns and Mechanism of Nitrogen Cycle During Biocrust Succession. Front Microbiol 2021; 12:633428. [PMID: 33815315 PMCID: PMC8009985 DOI: 10.3389/fmicb.2021.633428] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
The successional ecology of nitrogen cycling in biocrusts and the linkages to ecosystem processes remains unclear. To explore this, four successional stages of natural biocrust with five batches of repeated sampling and three developmental stages of simulated biocrust were studied using relative and absolute quantified multi-omics methods. A consistent pattern across all biocrust was found where ammonium assimilation, mineralization, dissimilatory nitrite to ammonium (DNiRA), and assimilatory nitrate to ammonium were abundant, while denitrification medium, N-fixation, and ammonia oxidation were low. Mathematic analysis showed that the nitrogen cycle in natural biocrust was driven by dissolved organic N and NO3–. pH and SO42– were the strongest variables affecting denitrification, while C:(N:P) was the strongest variable affecting N-fixation, DNiRA, nitrite oxidation, and dissimilatory nitrate to nitrite. Furthermore, N-fixation and DNiRA were closely related to elemental stoichiometry and redox balance, while assimilatory nitrite to ammonium (ANiRA) and mineralization were related to hydrological cycles. Together with the absolute quantification and network models, our results suggest that responsive ANiRA and mineralization decreased during biocrust succession; whereas central respiratory DNiRA, the final step of denitrification, and the complexity and interaction of the whole nitrogen cycle network increased. Therefore, our study stresses the changing environmental functions in the biocrust N-cycle, which are succession-dependent.
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Affiliation(s)
- Qiong Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yingchun Han
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shubin Lan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Chunxiang Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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31
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Concostrina-Zubiri L, Valencia E, Ochoa V, Gozalo B, Mendoza BJ, Maestre FT. Species-specific effects of biocrust-forming lichens on soil properties under simulated climate change are driven by functional traits. THE NEW PHYTOLOGIST 2021; 230:101-115. [PMID: 33314177 DOI: 10.1111/nph.17143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Biocrusts are key drivers of ecosystem functioning in drylands, yet our understanding of how climate change will affect the chemistry of biocrust-forming species and their impacts on carbon (C) and nitrogen (N) cycling is still very limited. Using a manipulative experiment conducted with common biocrust-forming lichens with distinct morphology and chemistry (Buellia zoharyi, Diploschistes diacapsis, Psora decipiens and Squamarina lentigera), we evaluated changes in lichen total and isotopic C and N and several soil C and N variables after 50 months of simulated warming and rainfall reduction. Climate change treatments reduced δ13 C and the C : N ratio in B. zoharyi, and increased δ15 N in S. lentigera. Lichens had species-specific effects on soil dissolved organic N (DON), NH4+ , β-glucosidase and acid phosphatase activity regardless of climate change treatments, while these treatments changed how lichens affected several soil properties regardless of biocrust species. Changes in thallus δ13 C, N and C : N drove species-specific effects on dissolved organic nitrogen (DON), NH4+ , β-glucosidase and acid phosphatase activity. Our findings indicate that warmer and drier conditions will alter the chemistry of biocrust-forming lichens, affecting soil nutrient cycling, and emphasize their key role as modulators of climate change impacts in dryland soils.
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Affiliation(s)
- Laura Concostrina-Zubiri
- Área de Biodiversidad y Conservación, Departamento de Biología, Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, C/Tulipán s/n, Móstoles, 28933, Spain
| | - Enrique Valencia
- Área de Biodiversidad y Conservación, Departamento de Biología, Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, C/Tulipán s/n, Móstoles, 28933, Spain
| | - Victoria Ochoa
- Instituto Multidisciplinar para el Estudio del Medio 'Ramon Margalef', Edificio Nuevos Institutos, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, 03690, Spain
| | - Beatriz Gozalo
- Instituto Multidisciplinar para el Estudio del Medio 'Ramon Margalef', Edificio Nuevos Institutos, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, 03690, Spain
| | - Betty J Mendoza
- Área de Biodiversidad y Conservación, Departamento de Biología, Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, C/Tulipán s/n, Móstoles, 28933, Spain
| | - Fernando T Maestre
- Instituto Multidisciplinar para el Estudio del Medio 'Ramon Margalef', Edificio Nuevos Institutos, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, 03690, Spain
- Departamento de Ecología, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, San Vicente del Raspeig, Alicante, 03690, Spain
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Su Y, Liu J, Zhang Y, Huang G. More drought leads to a greater significance of biocrusts to soil multifunctionality. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13761] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Yan‐gui Su
- Key Laboratory for Subtropical Mountain Ecology School of Geographical Sciences Fujian Normal University Fuzhou Fujian China
| | - Jie Liu
- Key Laboratory of Biogeography and Bioresource in Arid Land Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi Xinjiang China
| | - Yuan‐ming Zhang
- Key Laboratory of Biogeography and Bioresource in Arid Land Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi Xinjiang China
| | - Gang Huang
- Key Laboratory for Subtropical Mountain Ecology School of Geographical Sciences Fujian Normal University Fuzhou Fujian China
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Faist AM, Antoninka AJ, Barger NN, Bowker MA, Chaudhary VB, Havrilla CA, Huber-Sannwald E, Reed SC, Weber B. Broader Impacts for Ecologists: Biological Soil Crust as a Model System for Education. Front Microbiol 2021; 11:577922. [PMID: 33469449 PMCID: PMC7813986 DOI: 10.3389/fmicb.2020.577922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/30/2020] [Indexed: 11/18/2022] Open
Abstract
Biological soil crusts (biocrusts) are a complex community of algae, cyanobacteria, lichens, bryophytes, and assorted bacteria, fungi, archaea, and bacteriophages that colonize the soil surface. Biocrusts are particularly common in drylands and are found in arid and semiarid ecosystems worldwide. While diminutive in size, biocrusts often cover large terrestrial areas, provide numerous ecosystem benefits, enhance biodiversity, and are found in multiple configurations and assemblages across different climate and disturbance regimes. Biocrusts have been a focus of many ecologists, especially those working in semiarid and arid lands, as biocrusts are foundational community members, play fundamental roles in ecosystem processes, and offer rare opportunities to study biological interactions at small and large spatial scales. Due to these same characteristics, biocrusts have the potential to serve as an excellent teaching tool. The purpose of this paper is to demonstrate the utility of biocrust communities as a model system in science education. Functioning as portable, dynamic mini ecosystems, biocrusts can be used to teach about organisms, biodiversity, biotic interactions, abiotic controls, ecosystem processes, and even global change, and can be easy to use in nearly every classroom setup. For example, education principles, such as evolution and adaptation to stress, or structure and function (patterns and processes) can be applied by bringing biocrusts into the classroom as a teaching tool. In addition, discussing the utility of biocrusts in the classroom – including theory, hypothesis testing, experimentation, and hands-on learning – this document also provides tips and resources for developing education tools and activities geared toward impactful learning.
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Affiliation(s)
- Akasha M Faist
- Department of Animal and Range Sciences, New Mexico State University, Las Cruces, NM, United States
| | - Anita J Antoninka
- School of Forestry, Northern Arizona University, Flagstaff, AZ, United States
| | - Nichole N Barger
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, United States
| | - Matthew A Bowker
- School of Forestry, Northern Arizona University, Flagstaff, AZ, United States
| | - V Bala Chaudhary
- Department of Environmental Science and Studies, DePaul University, Chicago, IL, United States
| | - Caroline A Havrilla
- US Geological Survey, Southwest Biological Science Center, Flagstaff, AZ, United States.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| | - Elisabeth Huber-Sannwald
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, San Luis Potosí, Mexico
| | - Sasha C Reed
- US Geological Survey, Southwest Biological Science Center, Moab, UT, United States
| | - Bettina Weber
- Department of Biology, University of Graz, Graz, Austria.,Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
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Phillips ML, Winkler DE, Reibold RH, Osborne BB, Reed SC. Muted responses to chronic experimental nitrogen deposition on the Colorado Plateau. Oecologia 2021; 195:513-524. [PMID: 33415421 DOI: 10.1007/s00442-020-04841-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/17/2020] [Indexed: 10/22/2022]
Abstract
Anthropogenic nitrogen (N) deposition is significantly altering both community structure and ecosystem processes in terrestrial ecosystems across the globe. However, our understanding of the consequences of N deposition in dryland systems remains relatively poor, despite evidence that drylands may be particularly vulnerable to increasing N inputs. In this study, we investigated the influence of 7 years of multiple levels of simulated N deposition (0, 2, 5, and 8 kg N ha-1 year-1) on plant community structure and biological soil crust (biocrust) cover at three semi-arid grassland sites spanning a soil texture gradient. Biocrusts are a surface community of mosses, lichens, cyanobacteria, and/or algae, and have been shown to be sensitive to N inputs. We hypothesized that N additions would decrease plant diversity, increase abundance of the invasive annual grass Bromus tectorum, and decrease biocrust cover. Contrary to our expectations, we found that N additions did not affect plant diversity or B. tectorum abundance. In partial support of our hypotheses, N additions negatively affected biocrust cover in some years, perhaps driven in part by inter-annual differences in precipitation. Soil inorganic N concentrations showed rapid but ephemeral responses to N additions and plant foliar N concentrations showed no response, indicating that the magnitude of plant and biocrust responses to N fertilization may be buffered by endogenous N cycling. More work is needed to determine N critical load thresholds for plant community and biocrust dynamics in semi-arid systems and the factors that determine the fate of N inputs.
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Affiliation(s)
- Michala L Phillips
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA.
| | - Daniel E Winkler
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
| | - Robin H Reibold
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
| | - Brooke B Osborne
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
| | - Sasha C Reed
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
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Bi Y, Guo Y, Sun H. Arbuscular mycorrhizal fungal diversity in soils underlying moss biocrusts in coal mining subsidence areas. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:3484-3493. [PMID: 32918685 DOI: 10.1007/s11356-020-10726-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
The potentially symbiotic mycorrhizal associations dominated by arbuscular mycorrhizal (AM) fungi have become a new topic in bioremediation research in response to global change. Biological soil crusts (biocrusts) play an important role in arid and semi-arid ecosystems. However, AM fungal diversity in the soils underlying moss biocrusts in coal mining subsidence areas remains poorly understood. Here, samples of the soil underlying moss biocrusts in an area inoculated with an AM fungus (AM-BS) and an uninoculated area (CK-BS) plus soil samples from an uninoculated bare area (CK-NBS) were collected from the subsidence area of Shendong Daliuta mine at Yulin, northwest China. AM fungal community diversity indices were maximum in AM-BS, intermediate in CK-BS, and minimum in CK-NBS (P < 0.05). In addition, redundancy analysis (RDA) indicates that the importance of moss biocrust to soil properties followed the sequence: soil water content (SWC) > glomalin-related soil protein (TG) > available phosphorus (Olsen-P) > soil organic matter (SOM) > easily extractable glomalin-related soil protein (EEG) > pH > available nitrogen (alkali-N). SWC, alkali-N, Olsen-P, and SOM were significantly related to the abundance of Glomus and Claroideoglomus, and TG, EEG, and pH were positively related to Diversisipora. In summary, inoculation with the exotic AM fungus and moss biocrust cover created a eutrophic microhabitat for AM fungi in the soils underlying moss biocrusts in the coal mining subsidence area.
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Affiliation(s)
- Yinli Bi
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), Beijing, 100083, China.
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, 710054, China.
| | - Yun Guo
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Huan Sun
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), Beijing, 100083, China
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Tucker C, Ferrenberg S, Reed SC. Modest Residual Effects of Short-Term Warming, Altered Hydration, and Biocrust Successional State on Dryland Soil Heterotrophic Carbon and Nitrogen Cycling. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.467157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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A symbiotic nutrient exchange within the cyanosphere microbiome of the biocrust cyanobacterium, Microcoleus vaginatus. ISME JOURNAL 2020; 15:282-292. [PMID: 32968213 DOI: 10.1038/s41396-020-00781-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/26/2020] [Accepted: 09/10/2020] [Indexed: 02/01/2023]
Abstract
Microcoleus vaginatus plays a prominent role as both primary producer and pioneer in biocrust communities from dryland soils. And yet, it cannot fix dinitrogen, essential in often nitrogen-limited drylands. But a diazotroph-rich "cyanosphere" has been described in M. vaginatus, hinting that there exists a C for N exchange between the photoautotroph and heterotrophic diazotrophs. We provide evidence for this by establishing such a symbiosis in culture and by showing that it is selective and dependent on nitrogen availability. In natural populations, provision of nitrogen resulted in loss of diazotrophs from the cyanosphere of M. vaginatus compared to controls, but provision of phosphorus did not. Co-culturing of pedigreed cyanosphere diazotroph isolates with axenic M. vaginatus resulted in copious growth in C and N-free medium, but co-culture with non-cyanosphere diazotrophs or other heterotrophs did not. Unexpectedly, bundle formation in M. vaginatus, diacritical to the genus but not seen in axenic culture, was restored in vitro by imposed nitrogen limitation or, even more strongly, by co-culture with diazotrophic partners, implicating this trait in the symbiosis. Our findings provide direct evidence for a symbiotic relationship between M. vaginatus and its cyanosphere and help explain how it can be a global pioneer in spite of its genetic shortcomings.
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A Fog-Irrigated Soil Substrate System Unifies and Optimizes Cyanobacterial Biocrust Inoculum Production. Appl Environ Microbiol 2020; 86:AEM.00624-20. [PMID: 32358005 DOI: 10.1128/aem.00624-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/23/2020] [Indexed: 02/01/2023] Open
Abstract
Biological soil crusts (biocrusts) are globally important microbial communities inhabiting the top layer of soils. They provide multiple services to dryland ecosystems but are particularly vulnerable to anthropogenic disturbance from which they naturally recover only slowly. Assisted inoculation with cyanobacteria is held as a promising approach to promote biocrust regeneration. Two different methodologies have been developed for this purpose: mass cultivation of biocrust pioneer species (such as the cyanobacteria Microcoleus spp.) on cellulose supports, and polymicrobial cultivation of biocrusts in soils within greenhouse settings. Here, we aimed to test a novel method to grow cyanobacterial biocrust inoculum based on fog irrigation of soil substrates (FISS) that can be used with either culture-based or mixed-community approaches. We found that the FISS system presents clear advantages over previous inoculum production methodologies; overall, FISS eliminates the need for specialized facilities and decreases user effort. Specifically, there were increased microbial yields and simplification of design compared to those of the culture-based and mixed-community approaches, respectively. Its testing also allows us to make recommendations on underexplored aspects of biocrust restoration: (i) field inoculation levels should be equal to or greater than the biomass found in the substrate and (ii) practices regarding evaluation of cyanobacterial biomass should, under certain circumstances, include proxies additional to chlorophyll a IMPORTANCE Biocrust inoculum production for use in dryland rehabilitation is a powerful tool in combating the degradation of dryland ecosystems. However, the facilities and effort required to produce high-quality inoculum are often a barrier to effective large-scale implementation by land managers. By unifying and optimizing the two foremost methods for cyanobacterial biocrust inoculum production, our work improves on the ease and cost with which biocrust restoration technology can be translated to practical widespread implementation.
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Biocrusts Modulate Responses of Nitrous Oxide and Methane Soil Fluxes to Simulated Climate Change in a Mediterranean Dryland. Ecosystems 2020. [DOI: 10.1007/s10021-020-00497-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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40
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Ayuso SV, Giraldo‐Silva A, Barger NN, Garcia‐Pichel F. Microbial inoculum production for biocrust restoration: testing the effects of a common substrate versus native soils on yield and community composition. Restor Ecol 2020. [DOI: 10.1111/rec.13127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Sergio Velasco Ayuso
- School of Life SciencesArizona State University Tempe AZ 85287 U.S.A
- Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA‐CONICET), Facultad de Agronomía, Universidad de Buenos Aires Buenos Aires C1417DSE Argentina
| | - Ana Giraldo‐Silva
- School of Life SciencesArizona State University Tempe AZ 85287 U.S.A
- Center for Fundamental and Applied Microbiomics, Biodesign InstituteArizona State University Tempe AZ 85287 U.S.A
| | - Nichole N. Barger
- Department of Ecology and Evolutionary BiologyUniversity of Colorado Boulder CO 80309 U.S.A
| | - Ferran Garcia‐Pichel
- School of Life SciencesArizona State University Tempe AZ 85287 U.S.A
- Center for Fundamental and Applied Microbiomics, Biodesign InstituteArizona State University Tempe AZ 85287 U.S.A
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41
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Szyja M, Menezes AGDS, Oliveira FDA, Leal I, Tabarelli M, Büdel B, Wirth R. Neglected but Potent Dry Forest Players: Ecological Role and Ecosystem Service Provision of Biological Soil Crusts in the Human-Modified Caatinga. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00482] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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42
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Fick SE, Day N, Duniway MC, Hoy‐Skubik S, Barger NN. Microsite enhancements for soil stabilization and rapid biocrust colonization in degraded drylands. Restor Ecol 2019. [DOI: 10.1111/rec.13071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stephen E. Fick
- US Geological Survey Southwest Biological Science Center Moab UT U.S.A
- Department of Ecology and Evolutionary BiologyUniversity of Colorado Boulder CO U.S.A
| | - Natalie Day
- US Geological Survey Southwest Biological Science Center Moab UT U.S.A
| | | | - Sean Hoy‐Skubik
- US Geological Survey Southwest Biological Science Center Moab UT U.S.A
| | - Nichole N. Barger
- Department of Ecology and Evolutionary BiologyUniversity of Colorado Boulder CO U.S.A
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43
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Giraldo‐Silva A, Nelson C, Penfold C, Barger NN, Garcia‐Pichel F. Effect of preconditioning to the soil environment on the performance of 20 cyanobacterial strains used as inoculum for biocrust restoration. Restor Ecol 2019. [DOI: 10.1111/rec.13048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ana Giraldo‐Silva
- School of Life SciencesArizona State University Tempe AZ 85287 U.S.A
- Center for Fundamental and Applied Microbiomics, Biodesign InstituteArizona State University Tempe AZ 85287 U.S.A
| | - Corey Nelson
- School of Life SciencesArizona State University Tempe AZ 85287 U.S.A
- Center for Fundamental and Applied Microbiomics, Biodesign InstituteArizona State University Tempe AZ 85287 U.S.A
| | - Cory Penfold
- School of Life SciencesArizona State University Tempe AZ 85287 U.S.A
| | - Nichole N. Barger
- Department of Ecology and Evolutionary BiologyUniversity of Colorado Boulder CO 80309 U.S.A
| | - Ferran Garcia‐Pichel
- School of Life SciencesArizona State University Tempe AZ 85287 U.S.A
- Center for Fundamental and Applied Microbiomics, Biodesign InstituteArizona State University Tempe AZ 85287 U.S.A
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44
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Moreira-Grez B, Tam K, Cross AT, Yong JWH, Kumaresan D, Nevill P, Farrell M, Whiteley AS. The Bacterial Microbiome Associated With Arid Biocrusts and the Biogeochemical Influence of Biocrusts Upon the Underlying Soil. Front Microbiol 2019; 10:2143. [PMID: 31608023 PMCID: PMC6768011 DOI: 10.3389/fmicb.2019.02143] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 08/30/2019] [Indexed: 02/01/2023] Open
Abstract
Biocrusts are aggregated crusts that exist on the soil surface of arid environments. They are complex microbial communities comprised of cyanobacteria, lichens, mosses, algae and fungi. Recently, biocrusts have gained significant attention due to their ubiquitous distribution and likely important ecological roles, including soil stabilization, soil moisture retention, carbon (C) and nitrogen (N) fixation, as well as microbial engineers for semi-arid ecosystem restoration. Here, we collected three co-occurring types of biocrust (Cyanobacterial crust, Crustose lichen, and Foliose lichen) and their underlying soil from arid zones within Western Australia. Bacterial microbiome composition was determined through 16S rRNA gene amplicon sequencing to assess the extent of microbiome selection within the crusts versus underlying soil and biogeochemical measures performed to determine whether the crusts had significant impact upon the underlying soil for nutrient input. We determined that the bacterial communities of native biocrusts are distinct from those in their underlying soil, where dominant bacterial taxa differed according to crust morphologies. δ15N revealed that N-fixation appeared most evident in Foliose lichen crust (1.73 ± 1.04‰). Consequently, depending upon the crust type, biocrusts contained higher concentrations of organic C (2 to 50 times), total N (4 to 16 times) and available ammonium (2 to 4 times), though this enrichment did not extend to the soils underneath them. These findings demonstrate that biocrust communities are seemingly islands of biological activity in an arid landscape, uniquely different from their surrounding and underlying soil.
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Affiliation(s)
- Benjamin Moreira-Grez
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Perth, WA, Australia
| | - Kang Tam
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Perth, WA, Australia
- Centre for Mine Site Restoration, Department of Environment and Agriculture, Curtin University, Perth, WA, Australia
| | - Adam T. Cross
- Centre for Mine Site Restoration, Department of Environment and Agriculture, Curtin University, Perth, WA, Australia
| | - Jean W. H. Yong
- Centre for Mine Site Restoration, Department of Environment and Agriculture, Curtin University, Perth, WA, Australia
- School of Biological Sciences, Faculty of Science, The University of Western Australia, Perth, WA, Australia
- Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Deepak Kumaresan
- School of Biological Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Paul Nevill
- Centre for Mine Site Restoration, Department of Environment and Agriculture, Curtin University, Perth, WA, Australia
| | - Mark Farrell
- CSIRO Agriculture and Food, Urrbrae, SA, Australia
| | - Andrew S. Whiteley
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Perth, WA, Australia
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Reed SC, Delgado-Baquerizo M, Ferrenberg S. Biocrust science and global change. THE NEW PHYTOLOGIST 2019; 223:1047-1051. [PMID: 31304606 DOI: 10.1111/nph.15992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Sasha C Reed
- US Geological Survey, Southwest Biological Science Center, Moab, UT, 84532, USA
| | - Manuel Delgado-Baquerizo
- Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Calle Tulipán Sin Número, Móstoles, 28933, Spain
| | - Scott Ferrenberg
- Department of Biology, New Mexico State University, Las Cruces, NM, 88001, USA
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46
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Mallen‐Cooper M, Bowker MA, Antoninka AJ, Eldridge DJ. A practical guide to measuring functional indicators and traits in biocrusts. Restor Ecol 2019. [DOI: 10.1111/rec.12974] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Max Mallen‐Cooper
- Centre for Ecosystem Science, School of Biological, Earth and Environmental SciencesUniversity of New South Wales Sydney NSW Australia
- Ecology and Evolution Research Centre, School of Biological, Earth and Environmental SciencesUniversity of New South Wales Sydney NSW Australia
| | | | | | - David J. Eldridge
- Centre for Ecosystem Science, School of Biological, Earth and Environmental SciencesUniversity of New South Wales Sydney NSW Australia
- Ecology and Evolution Research Centre, School of Biological, Earth and Environmental SciencesUniversity of New South Wales Sydney NSW Australia
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47
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Doherty K, Bowker MA, Durham RA, Antoninka A, Ramsey P, Mummey D. Adapting mechanized vascular plant seed dispersal technologies to biocrust moss restoration. Restor Ecol 2019. [DOI: 10.1111/rec.12998] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kyle Doherty
- School of ForestryNorthern Arizona University 200 E. Pine Knoll Dr., Box 15018, Flagstaff AZ 86011 U.S.A
| | - Matthew A. Bowker
- School of ForestryNorthern Arizona University 200 E. Pine Knoll Dr., Box 15018, Flagstaff AZ 86011 U.S.A
| | | | - Anita Antoninka
- School of ForestryNorthern Arizona University 200 E. Pine Knoll Dr., Box 15018, Flagstaff AZ 86011 U.S.A
| | - Philip Ramsey
- MPG Ranch 1001 S. Higgins Avenue STE A3, Missoula MT 59801 U.S.A
| | - Daniel Mummey
- MPG Ranch 1001 S. Higgins Avenue STE A3, Missoula MT 59801 U.S.A
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Optimizing the Production of Nursery-Based Biological Soil Crusts for Restoration of Arid Land Soils. Appl Environ Microbiol 2019; 85:AEM.00735-19. [PMID: 31152015 PMCID: PMC6643228 DOI: 10.1128/aem.00735-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/22/2019] [Indexed: 12/13/2022] Open
Abstract
Biocrust 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. Biological 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. IMPORTANCE Biocrust 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.
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Habitat-dependent composition of bacterial and fungal communities in biological soil crusts from Oman. Sci Rep 2019; 9:6468. [PMID: 31015576 PMCID: PMC6478931 DOI: 10.1038/s41598-019-42911-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 04/09/2019] [Indexed: 11/08/2022] Open
Abstract
Biological soil crusts (biocrusts) occur within drylands throughout the world, covering ~12% of the global terrestrial soil surface. Their occurrence in the deserts of the Arabian Peninsula has rarely been reported and their spatial distribution, diversity, and microbial composition remained largely unexplored. We investigated biocrusts at six different locations in the coastal and central deserts of Oman. The biocrust types were characterized, and the bacterial and fungal community compositions of biocrusts and uncrusted soils were analysed by amplicon sequencing. The results were interpreted based on the environmental parameters of the different sites. Whereas at lowland sites, mainly cyanobacteria-dominated biocrusts were observed, both cyanobacteria- and lichen-dominated biocrusts occurred at mountain sites. The majority of bacterial sequences (32–83% of total sequences) belonged to Actinobacteria, Cyanobacteria, Alphaproteobacteria, and Bacteroidetes, whereas fungal sequences belonged to Ascomycota, Basidiomycota, and Chytridiomycota (>95%). With biocrust development, a notable increase in cyanobacterial and decrease in actinobacterial proportions was observed for cyanobacteria-dominated crusts. In coastal areas, where salinity is high, biocrusts were replaced by a unique marine mat-like microbial community, dominated by halotolerant taxa. Redundancy analysis revealed a significant contribution of soil texture, cover type, carbon content, and elevation to the variations in bacterial and fungal communities. Multivariate analysis placed microbial communities in significantly separated clusters based on their carbon content, elevation and electrical conductivity. We conclude that Oman hosts a variety of cyanobacteria- and lichen-dominated crusts with their bacterial and fungal communities being largely dictated by soil properties and environmental parameters.
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Couradeau E, Giraldo-Silva A, De Martini F, Garcia-Pichel F. Spatial segregation of the biological soil crust microbiome around its foundational cyanobacterium, Microcoleus vaginatus, and the formation of a nitrogen-fixing cyanosphere. MICROBIOME 2019; 7:55. [PMID: 30944036 PMCID: PMC6448292 DOI: 10.1186/s40168-019-0661-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 03/11/2019] [Indexed: 05/13/2023]
Abstract
BACKGROUND Biological soil crusts (biocrusts) are a key component of arid land ecosystems, where they render critical services such as soil surface stabilization and nutrient fertilization. The bundle-forming, filamentous, non-nitrogen-fixing cyanobacterium Microcoleus vaginatus is a pioneer primary producer, often the dominant member of the biocrust microbiome, and the main source of leaked organic carbon. We hypothesized that, by analogy to the rhizosphere of plant roots, M. vaginatus may shape the microbial populations of heterotrophs around it, forming a specialized cyanosphere. RESULTS By physically isolating bundles of M. vaginatus from biocrusts, we were able to study the composition of the microbial populations attached to it, in comparison to the bulk soil crust microbiome by means of high-throughput 16S rRNA sequencing. We did this in two M. vaginatus-dominated biocrust from distinct desert biomes. We found that a small, selected subset of OTUs was significantly enriched in close proximity to M. vaginatus. Furthermore, we also found that a majority of bacteria (corresponding to some two thirds of the reads) were significantly more abundant away from this cyanobacterium. Phylogenetic placements suggest that all typical members of the cyanosphere were copiotrophs and that many were diazotrophs (Additional file 1: Tables S2 and S3). Nitrogen fixation genes were in fact orders of magnitude more abundant in this cyanosphere than in the bulk biocrust soil as assessed by qPCR. By contrary, competition for light, CO2, and low organic carbon concentrations defined at least a part of the OTUs segregating from the cyanobacterium. CONCLUSIONS We showed that M. vaginatus acts as a significant spatial organizer of the biocrust microbiome. On the one hand, it possesses a compositionally differentiated cyanosphere that concentrates the nitrogen-fixing function. We propose that a mutualism based on C for N exchange between M. vaginatus and copiotrophic diazotrophs helps sustains this cyanosphere and that this consortium constitutes the true pioneer community enabling the colonization of nitrogen-poor soils. On the other hand, a large number of biocrust community members segregate away from the vicinity of M. vaginatus, potentially through competition for light or CO2, or because of a preference for oligotrophy.
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Affiliation(s)
- Estelle Couradeau
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ 85287 USA
- Laboratoire Biogéosciences, Université de Bourgogne, Dijon, France
- Present Address: Joint Genome Institute (DOE), Lawrence Berkeley National Lab (LBNL), 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Ana Giraldo-Silva
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ 85287 USA
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, 1001 S. McAllister Ave., Tempe, AZ 85282 USA
| | - Francesca De Martini
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ 85287 USA
| | - Ferran Garcia-Pichel
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ 85287 USA
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, 1001 S. McAllister Ave., Tempe, AZ 85282 USA
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