{"type": "FeatureCollection", "features": [{"id": "10.1002/ajb2.70086", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:13:56Z", "type": "Journal Article", "created": "2025-08-12", "title": "Moss\u2010cyanobacteria associations: A model for studying symbiotic interactions and evolutionary strategies", "keywords": ["forests", "mosses", "non-vascular plants", "nitrogen fixation", "symbioses", "On the Nature of Things", "cyanobacteria", "model organisms"], "contacts": [{"organization": "Kathrin Rousk", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1002/ajb2.70086"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/American%20Journal%20of%20Botany", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1002/ajb2.70086", "name": "item", "description": "10.1002/ajb2.70086", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1002/ajb2.70086"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-08-01T00:00:00Z"}}, {"id": "10.1007/s00248-024-02363-6", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:14:16Z", "type": "Journal Article", "created": "2024-03-01", "title": "The Feather Moss Hylocomium splendens Affects the Transcriptional Profile of a Symbiotic Cyanobacterium in Relation to Acquisition and Turnover of Key Nutrients", "description": "Abstract

Moss-cyanobacteria symbioses were proposed to be based on nutrient exchange, with hosts providing C and S while bacteria provide N, but we still lack understanding of the underlying molecular mechanisms of their interactions. We investigated how contact between the ubiquitous moss Hylocomium splendens and its cyanobiont affects nutrient-related gene expression of both partners. We isolated a cyanobacterium from H. splendens and co-incubated it with washed H. splendens shoots. Cyanobacterium and moss were also incubated separately. After 1\uffc2\uffa0week, we performed acetylene reduction assays to estimate N2 fixation and RNAseq to evaluate metatranscriptomes. Genes related to N2 fixation and the biosynthesis of several amino acids were up-regulated in the cyanobiont when hosted by the moss. However, S-uptake and the biosynthesis of the S-containing amino acids methionine and cysteine were down-regulated in the cyanobiont while the degradation of selenocysteine was up-regulated. In contrast, the number of differentially expressed genes in the moss was much lower, and almost no transcripts related to nutrient metabolism were affected. It is possible that, at least during the early stage of this symbiosis, the cyanobiont receives few if any nutrients from the host in return for N, suggesting that moss\uffe2\uff80\uff93cyanobacteria symbioses encompass relationships that are more plastic than a constant mutualist flow of nutrients.Abstract

Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha\u22121 yr\u22121) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha\u22121 yr\u22121) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

", "keywords": ["0301 basic medicine", "0303 health sciences", "03 medical and health sciences", "Sphagnum", "Nitrogen fixation", "Nitrogen pollution", "Organic nitrogen", "15. Life on land", "Cyanobacteria", "Feathermosses"]}, "links": [{"href": "https://doi.org/10.1007/s10533-022-00920-0"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s10533-022-00920-0", "name": "item", "description": "10.1007/s10533-022-00920-0", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s10533-022-00920-0"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-08T00:00:00Z"}}, {"id": "10.1007/s10750-009-9715-y", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:14:42Z", "type": "Journal Article", "created": "2009-02-13", "title": "Heterotrophic Nitrogen Fixation In Oligotrophic Tropical Marshes: Changes After Phosphorus Addition", "description": "In order to determine the impact of nutrient enrichment on phosphorus (P) limited wetlands, we established experimental P additions in marshes throughout northern Belize. P significantly increased macrophyte primary production, which led to the rapid elimination of cyanobacterial mats. The replacement of cyanobacterial mats by macrophytes constrained autotrophic nitrogen (N) fixation, increased the quantity, and changed the quality of organic matter input to the sediments. We predicted that the activity of sediment heterotrophic N fixers will be impacted by these alterations in carbon input. We used the acetylene reduction technique to measure potential (glucose amended) nitrogenase activity (NA) in sediments from controls and treatment plots that have been P enriched for four years and dominated either by Eleocharis cellulosa, or Typha domingensis for two years. NA in P-enriched plots was 2\u20133 orders of magnitude higher than NA in controls. NA was positively correlated with the soil reactive P, both total organic and microbial carbon, live root biomass, and total phospholipid fatty acids (PLFA) as an indicator of active microbial biomass. It was negatively correlated with the concentration of ammonium-N. Path analysis revealed that the indirect effect of P on NA through the root biomass was more important than the direct effect of P. NA of the upper sediment layer was consistently higher in Eleocharis than in Typha dominated plots, despite the higher litter input by Typha. We feel that the higher levels of lignin and phenolics occurring in Typha litter, relative to Eleocharis, constrained NA in Typha plots.", "keywords": ["0106 biological sciences", "Freshwater & Marine Ecology", "Salinity", "Ecology", "Life Sciences", "Phosphorus", "04 agricultural and veterinary sciences", "Aquatic Science", "15. Life on land", "Cyanobacteria", "Pollution", "01 natural sciences", "6. Clean water", "Environmental Science(all)", "13. Climate action", "Heterotrophic nitrogen fixation", "0401 agriculture", " forestry", " and fisheries", "Zoology", "Typha", "Eleocharis"], "contacts": [{"organization": "\u010cern\u00e1, Barbora, Rejm\u00e1nkov\u00e1, Eli\u0161ka, Snyder, Jenise M., \u0160antr\u016f\u010dkov\u00e1, Hana,", "roles": ["creator"]}]}, "links": [{"href": "https://escholarship.org/content/qt0xk5x7sm/qt0xk5x7sm.pdf"}, {"href": "https://doi.org/10.1007/s10750-009-9715-y"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Hydrobiologia", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s10750-009-9715-y", "name": "item", "description": "10.1007/s10750-009-9715-y", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s10750-009-9715-y"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2009-02-13T00:00:00Z"}}, {"id": "10.1016/j.actao.2021.103796", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:15:06Z", "type": "Journal Article", "created": "2021-10-26", "title": "Extreme freeze-thaw cycles do not affect moss-associated nitrogen fixation across a temperature gradient, but affect nutrient loss from mosses", "description": "Abstract Moss-associated nitrogen (N2) fixation performed by epiphytic, N2-fixing bacteria (diazotrophs) contributes significantly to ecosystem N input in pristine habitats. While we have some understanding of the effects of climate warming on moss-associated N2 fixation, we lack data on effects of freeze-thaw cycles (FTCs) on diazotroph activity, although increased frequency of FTCs is predicted. We collected the widespread moss Pleurozium schreberi along a climate gradient (temperate, boreal, arctic) and exposed moss and associated diazotrophs to severe (20\u00a0\u00b0C difference, cycling between +10 and \u221210\u00a0\u00b0C) and mild (6\u00a0\u00b0C difference, \u00b13\u00a0\u00b0C) diurnal FTCs. We measured N2 fixation in mosses over 8 weeks and assessed their nutrient loss (fixed N2, total dissolved N, ammonium, phosphate) during the FTCs. We expected lower nitrogenase activity in mosses exposed to more severe FTCs and different sensitivities of N2 fixation towards FTCs along the climate gradient. However, no differences were found in N2 fixation between mild and severe FTCs, but N2 fixation in mosses from the temperate heath was less susceptible to FTCs than those from colder sites, suggesting adapted temperate diazotroph communities. Mosses lost little N, most at constant, positive temperatures, while more phosphate was lost from mosses exposed to FTCs, depending on the positioning along the climate gradient, mirroring nutrient demand and limitation. Our results show that moss-associated N2 fixation is less susceptible towards FTCs than expected but nutrient loss from moss carpets can increase following FTCs, with consequences for nutrient pools and fluxes.", "keywords": ["0106 biological sciences", "Diazotrophs", "13. Climate action", "Nutrient limitation", "Climate change", "0401 agriculture", " forestry", " and fisheries", "Phosphorus", "04 agricultural and veterinary sciences", "15. Life on land", "Cyanobacteria", "Acetylene reduction", "01 natural sciences"]}, "links": [{"href": "https://doi.org/10.1016/j.actao.2021.103796"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Acta%20Oecologica", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.actao.2021.103796", "name": "item", "description": "10.1016/j.actao.2021.103796", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.actao.2021.103796"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-01T00:00:00Z"}}, {"id": "10.1038/nature01051", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:17:28Z", "type": "Journal Article", "created": "2002-10-30", "title": "Quantifying Nitrogen-Fixation In Feather Moss Carpets Of Boreal Forests", "description": "Biological nitrogen (N) fixation is the primary source of N within natural ecosystems, yet the origin of boreal forest N has remained elusive. The boreal forests of Eurasia and North America lack any significant, widespread symbiotic N-fixing plants. With the exception of scattered stands of alder in early primary successional forests, N-fixation in boreal forests is considered to be extremely limited. Nitrogen-fixation in northern European boreal forests has been estimated at only 0.5 kg N ha(-1) yr(-1); however, organic N is accumulated in these ecosystems at a rate of 3 kg N ha(-1) yr(-1) (ref. 8). Our limited understanding of the origin of boreal N is unacceptable given the extent of the boreal forest region, but predictable given our imperfect knowledge of N-fixation. Herein we report on a N-fixing symbiosis between a cyanobacterium (Nostoc sp.) and the ubiquitous feather moss, Pleurozium schreberi (Bird) Mitt. that alone fixes between 1.5 and 2.0 kg N ha(-1) yr(-1) in mid- to late-successional forests of northern Scandinavia and Finland. Previous efforts have probably underestimated N-fixation potential in boreal forests.", "keywords": ["Sweden", "0106 biological sciences", "Acetylene", "Norway", "04 agricultural and veterinary sciences", "15. Life on land", "Cyanobacteria", "01 natural sciences", "Bryopsida", "Trees", "Plant Leaves", "Kinetics", "Nitrogen Fixation", "0401 agriculture", " forestry", " and fisheries", "Symbiosis", "Finland"]}, "links": [{"href": "https://doi.org/10.1038/nature01051"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nature", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1038/nature01051", "name": "item", "description": "10.1038/nature01051", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1038/nature01051"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2002-10-31T00:00:00Z"}}, {"id": "10.1111/gcb.14399", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:18:33Z", "type": "Journal Article", "created": "2018-07-14", "title": "Pathways regulating decreased soil respiration with warming in a biocrust\u2010dominated dryland", "description": "Abstract

A positive soil carbon (C)\uffe2\uff80\uff90climate feedback is embedded into the climatic models of the IPCC. However, recent global syntheses indicate that the temperature sensitivity of soil respiration (RS) in drylands, the largest biome on Earth, is actually lower in warmed than in control plots. Consequently, soil C losses with future warming are expected to be low compared with other biomes. Nevertheless, the empirical basis for these global extrapolations is still poor in drylands, due to the low number of field experiments testing the pathways behind the long\uffe2\uff80\uff90term responses of soil respiration (RS) to warming. Importantly, global drylands are covered with biocrusts (communities formed by bryophytes, lichens, cyanobacteria, fungi, and bacteria), and thus,RSresponses to warming may be driven by both autotrophic and heterotrophic pathways. Here, we evaluated the effects of 8\uffe2\uff80\uff90year experimental warming onRS, and the different pathways involved, in a biocrust\uffe2\uff80\uff90dominated dryland in southern Spain. We also assessed the overall impacts on soil organic C (SOC) accumulation over time. Across the years and biocrust cover levels, warming reducedRSby 0.30\uffc2\uffa0\uffce\uffbcmol\uffc2\uffa0CO2\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0s\uffe2\uff88\uff921(95% CI\uffc2\uffa0=\uffc2\uffa0\uffe2\uff88\uff920.24 to 0.84), although the negative warming effects were only significant after 3\uffc2\uffa0years of elevated temperatures in areas with low initial biocrust cover. We found support for different pathways regulating the warming\uffe2\uff80\uff90induced reduction inRSat areas with low (microbial thermal acclimation via reduced soil mass\uffe2\uff80\uff90specific respiration and \uffce\uffb2\uffe2\uff80\uff90glucosidase enzymatic activity) vs. high (microbial thermal acclimation jointly with a reduction in autotrophic respiration from decreased lichen cover) initial biocrust cover. Our 8\uffe2\uff80\uff90year experimental study shows a reduction in soil respiration with warming and highlights that biocrusts should be explicitly included in modeling efforts aimed to quantify the soil C\uffe2\uff80\uff93climate feedback in drylands. Due to their abilities to survive intense radiation and low water availability, hypersaline microbial mats are often suggested to be analogs of potential extraterrestrial life. However, even on Earth, the limitations imposed on microbial processes by saturation-level salinity have rarely been studied in situ .

", "keywords": ["aerobic respiration", "primary and secondary production", "0301 basic medicine", "Geologic Sediments", "hypersaline microbial mats", "microbial communities", "Sodium Chloride", "extremophiles/extremophily", "03 medical and health sciences", "CYANOBACTERIAL MATS", "REDUCING BACTERIA", "uncultured microbes", "BACTERIUM DESULFOVIBRIO-OXYCLINAE", "Environmental Microbiology", "14. Life underwater", "Photosynthesis", "Phylogeny", "DISSIMILATORY SULFATE REDUCTION", "106022 Mikrobiologie", "Bacteria", "Microbiota", "ANOXYGENIC PHOTOSYNTHESIS", "15. Life on land", "Archaea", "biofilm biology", "6. Clean water", "Oxygen", "sulfide microprofiles", "13. Climate action", "CHLOROFLEXUS-LIKE BACTERIA", "106022 Microbiology", "sulfate reduction rate", "GEN. NOV.", "sulfur cycling", "PHYSIOLOGICAL CHARACTERIZATION", "DUNALIELLA", "microbiology of unexplored habitats", "biofilm biology; element cycles and biogeochemical processes; extremophiles/extremophily; microbial communities; microbiology of unexplored habitats; primary and secondary production; uncultured microbes", "element cycles and biogeochemical processes", "key biogeochemical processes", "OXYGENIC PHOTOSYNTHESIS", "Sulfur"]}, "links": [{"href": "https://journals.asm.org/doi/pdf/10.1128/AEM.00698-21"}, {"href": "https://doi.org/10.1128/aem.00698-21"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Applied%20and%20Environmental%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1128/aem.00698-21", "name": "item", "description": "10.1128/aem.00698-21", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1128/aem.00698-21"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-08-11T00:00:00Z"}}, {"id": "10.1111/nph.17996", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:18:57Z", "type": "Journal Article", "created": "2022-01-28", "title": "Effects of vegetation on soil cyanobacterial communities through time and space", "description": "Summary

Photoautotrophic soil cyanobacteria play essential ecological roles and are known to exhibit large changes in their diversity and abundance throughout early succession. However, much less is known about how and why soil cyanobacterial communities change as soil develops over centuries and millennia, and the effects that vegetation have on such communities.

We combined an extensive field survey, including 16 global soil chronosequences across contrasting ecosystems (from deserts to tropical forests), with molecular analyses to investigate how the diversity and abundance of photosynthetic and nonphotosynthetic soil cyanobacteria are affected by vegetation change during soil development, over time periods from hundreds to thousands of years.

We show that, in most chronosequences, the abundance, species richness and community composition of soil cyanobacteria are relatively stable as soil develops (from centuries to millennia). Regardless of soil age, forest chronosequences were consistently dominated by nonphotosynthetic cyanobacteria (Vampirovibrionia), while grasslands and shrublands were dominated by photosynthetic cyanobacteria. Chronosequences undergoing drastic vegetation shifts (e.g. transitions from grasslands to forests) experienced significant changes in the composition of soil cyanobacterial communities.

Our results advance our understanding of the ecology of cyanobacterial classes, and of the understudied nonphotosynthetic cyanobacteria in particular, and highlight the key role of vegetation as a major driver of their temporal dynamics as soil develops.

Most mosses are colonized by nitrogen (N)\uffe2\uff80\uff90fixing cyanobacteria. This discovery is relatively recent, which can explain the large knowledge gaps the field is now tackling. For instance, while we have a good understanding of the abiotic controls (e.g. nutrient availability, increased temperature), we still do not know much about the biotic controls of N2 fixation in mosses. I propose here that we should endeavour to position moss\uffe2\uff80\uff93cyanobacteria associations along the mutualism\uffe2\uff80\uff93parasitism continuum under varying abiotic conditions (e.g. nutrient availability). This would finally unravel the nature of the relationship between the partners and will be a big leap in our understanding of the evolution of plant\uffe2\uff80\uff93bacteria interactions using moss\uffe2\uff80\uff93cyanobacteria associations as a model system.

Microbial life is surprisingly abundant and diverse in global desert ecosystems. In these environments, microorganisms endure a multitude of physicochemical stresses, including low water potential, carbon and nitrogen starvation, and extreme temperatures. In this review, we summarize our current understanding of the energetic mechanisms and trophic dynamics that underpin microbial function in desert ecosystems. Accumulating evidence suggests that dormancy is a common strategy that facilitates microbial survival in response to water and carbon limitation.

", "keywords": ["0301 basic medicine", "dormancy", "CYANOBACTERIAL EXOPOLYSACCHARIDES", "Trace gas", "Microbiology", "SOIL CRUSTS", "Energy reserve", "HIGH-AFFINITY", "03 medical and health sciences", "trace gas", "ATMOSPHERIC TRACE GASES", "Energetics", "energy reserve", "Dormancy", "SOR RONDANE MOUNTAINS", "Desert", "Photosynthesis", "106026 Ecosystem research", "CARBON-MONOXIDE", "desert", "ATACAMA DESERT", "energetics", "2. Zero hunger", "106022 Mikrobiologie", "0303 health sciences", "photosynthesis", "COMMUNITY RESPONSE", "15. Life on land", "QR1-502", "106026 \u00d6kosystemforschung", "DRY SOIL", "13. Climate action", "MOLECULAR-HYDROGEN", "106022 Microbiology", "Minireview"]}, "links": [{"href": "https://journals.asm.org/doi/pdf/10.1128/mSystems.00495-19"}, {"href": "https://doi.org/10.1128/msystems.00495-19"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/mSystems", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1128/msystems.00495-19", "name": "item", "description": "10.1128/msystems.00495-19", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1128/msystems.00495-19"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-04-28T00:00:00Z"}}, {"id": "10.21203/rs.3.rs-1022519/v1", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:19:50Z", "type": "Journal Article", "created": "2021-11-08", "title": "Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It", "description": "Abstract

Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha\u22121 yr\u22121) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha\u22121 yr\u22121) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

", "keywords": ["0301 basic medicine", "0303 health sciences", "03 medical and health sciences", "Sphagnum", "Nitrogen fixation", "Nitrogen pollution", "Organic nitrogen", "15. Life on land", "Cyanobacteria", "Feathermosses"]}, "links": [{"href": "https://doi.org/10.21203/rs.3.rs-1022519/v1"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.21203/rs.3.rs-1022519/v1", "name": "item", "description": "10.21203/rs.3.rs-1022519/v1", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.21203/rs.3.rs-1022519/v1"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-08T00:00:00Z"}}, {"id": "10.3389/fmicb.2020.568224", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:20:35Z", "type": "Journal Article", "created": "2020-10-27", "title": "Exopolysaccharide Features Influence Growth Success in Biocrust-forming Cyanobacteria, Moving From Liquid Culture to Sand Microcosms", "description": "Land degradation in drylands is a drawback of the combined action of climate change and human activities. New techniques have been developed to induce artificial biocrusts formation as a tool for restoration of degraded drylands, and among them soils inoculation with cyanobacteria adapted to environmental stress. Improvement of soil properties by cyanobacteria inoculation is largely related to their ability to synthesize exopolysaccharides (EPS). However, cyanobacterial EPS features [amount, molecular weight (MW), composition] can change from one species to another or when grown in different conditions. We investigated the differences in growth and polysaccharidic matrix features among three common biocrust-forming cyanobacteria (Nostoc commune, Scytonema javanicum, and Phormidium ambiguum), when grown in liquid media and on sandy soil microcosms under optimal nutrient and water, in controlled laboratory conditions. We extracted and analyzed the released EPS (RPS) and sheath for the liquid cultures, and the more soluble or loosely-bound (LB) and the more condensed or tightly-bound (TB) soil EPS fractions for the sandy soil microcosms. In liquid culture, P. ambiguum showed the greatest growth and EPS release. In contrast, on the sandy soil, S. javanicum showed the highest growth and highest LB-EPS content. N. commune showed no relevant growth after its inoculation of the sandy soil. A difference was observed in terms of MW distribution, showing that the higher MW of the polymers produced by P. ambiguum and S. javanicum compared to the polymers produced by N. commune, could have had a positive effect on growth for the first two organisms when inoculated on the sandy soil. We also observed how both RPS and sheath fractions reflected in the composition of the soil TB-EPS fraction, indicating the role in soil stabilization of both the released and the cell attached EPS. Our results indicate that the features of the polysaccharidic matrix produced by different cyanobacteria can influence their growth success in soil. These results are of great relevance when selecting suitable candidates for large-scale cyanobacteria applications in soil restoration.", "keywords": ["0301 basic medicine", "2. Zero hunger", "0303 health sciences", "EPS monosaccharidic composition", "15. Life on land", "sand inoculation", "semiarid soil", "Microbiology", "QR1-502", "6. Clean water", "03 medical and health sciences", "EPS molecular weight distribution", "13. Climate action", "cyanobacteria liquid culture", "cyanobacteria liquid culture", " sand inoculation", " sandy soil microcosms", " EPS monosaccharidic composition", " EPS molecular weight distribution", " semiarid soil", "sandy soil microcosms"]}, "links": [{"href": "https://flore.unifi.it/bitstream/2158/1215077/2/fmicb-11-568224.pdf"}, {"href": "https://doi.org/10.3389/fmicb.2020.568224"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3389/fmicb.2020.568224", "name": "item", "description": "10.3389/fmicb.2020.568224", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3389/fmicb.2020.568224"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-10-27T00:00:00Z"}}, {"id": "10.3390/ijms26020673", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:20:48Z", "type": "Journal Article", "created": "2025-01-15", "title": "Biofilm Formation, Modulation, and Transcriptomic Regulation Under Stress Conditions in Halomicronema sp.", "description": "

In nature, bacteria often form heterogeneous communities enclosed in a complex matrix known as biofilms. This extracellular matrix, produced by the microorganisms themselves, serves as the first barrier between the cells and the environment. It is composed mainly of water, extracellular polymeric substances (EPS), lipids, proteins, and DNA. Cyanobacteria form biofilms and have unique characteristics such as oxygenic photosynthesis, nitrogen fixation, excellent adaptability to various abiotic stress conditions, and the ability to secrete a variety of metabolites and hormones. This work focused on the characterization of the cyanobacterium Halomicronema sp. strain isolated from a brackish environment. This study included microscopic imaging, determination of phenolic content and antioxidant capacity, identification of chemicals interfering with biofilm formation, and transcriptomic analysis by RNA sequencing and real-time PCR. Gene expression analysis was centered on genes related to the production of EPS and biofilm-related transcription factors. This study led to the identification of wza1 and wzt as EPS biomarkers and luxR-05665, along with genes belonging to the TetR/AcrR and LysR families, as potential biomarkers useful for studying and monitoring biofilm formation under different environmental conditions. Moreover, this work revealed that Halomicronema sp. can grow even in the presence of strong abiotic stresses, such as high salt, and has good antioxidant properties.

", "keywords": ["570", "Extracellular Polymeric Substance Matrix", "Gene Expression Profiling", "Gene Expression Regulation", " Bacterial", "stress resilience", "Cyanobacteria", "cyanobacteria", "Article", "transcriptomics", "Bacterial Proteins", "Halomicronema sp", "Stress", " Physiological", "Biofilms", "biofilm formation", "EPS", "Transcriptome"], "contacts": [{"organization": "Marina Caldara, Henk Bolhuis, Marta Marmiroli, Nelson Marmiroli,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.3390/ijms26020673"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/International%20Journal%20of%20Molecular%20Sciences", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/ijms26020673", "name": "item", "description": "10.3390/ijms26020673", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/ijms26020673"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-01-15T00:00:00Z"}}, {"id": "10.3390/plants12071443", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:20:53Z", "type": "Journal Article", "created": "2023-03-24", "title": "Do Nitrogen and Phosphorus Additions Affect Nitrogen Fixation Associated with Tropical Mosses?", "description": "

Tropical cloud forests are characterized by abundant and biodiverse mosses which grow epiphytically as well as on the ground. Nitrogen (N)-fixing cyanobacteria live in association with most mosses, and contribute greatly to the N pool via biological nitrogen fixation (BNF). However, the availability of nutrients, especially N and phosphorus (P), can influence BNF rates drastically. To evaluate the effects of increased N and P availability on BNF in mosses, we conducted a laboratory experiment where we added N and P, in isolation and combined, to three mosses (Campylopus sp., Dicranum sp. and Thuidium peruvianum) collected from a cloud forest in Peru. Our results show that N addition almost completely inhibited BNF within a day, whereas P addition caused variable results across moss species. Low N2 fixation rates were observed in Campylopus sp. across the experiment. BNF in Dicranum sp. was decreased by all nutrients, while P additions seemed to promote BNF in T. peruvianum. Hence, each of the three mosses contributes distinctively to the ecosystem N pool depending on nutrient availability. Moreover, increased N input will likely significantly decrease BNF associated with mosses also in tropical cloud forests, thereby limiting N input to these ecosystems via the moss-cyanobacteria pathway.

", "keywords": ["nutrient limitation", "cyanobacteria; ecosystem ecology; global change; mosses; nitrogen fixation; nutrient limitation; phosphorus; tropical cloud forest", "Botany", "ecosystem ecology", "15. Life on land", "Milj\u00f6vetenskap", "cyanobacteria", "Article", "mosses", "13. Climate action", "nitrogen fixation", "QK1-989", "tropical cloud forest", "phosphorus", "Environmental Sciences", "global change"]}, "links": [{"href": "http://www.mdpi.com/2223-7747/12/7/1443/pdf"}, {"href": "https://www.mdpi.com/2223-7747/12/7/1443/pdf"}, {"href": "https://doi.org/10.3390/plants12071443"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plants", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/plants12071443", "name": "item", "description": "10.3390/plants12071443", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/plants12071443"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2023-03-24T00:00:00Z"}}, {"id": "11381/3018373", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:24:57Z", "type": "Journal Article", "created": "2025-01-15", "title": "Biofilm Formation, Modulation, and Transcriptomic Regulation Under Stress Conditions in Halomicronema sp.", "description": "

In nature, bacteria often form heterogeneous communities enclosed in a complex matrix known as biofilms. This extracellular matrix, produced by the microorganisms themselves, serves as the first barrier between the cells and the environment. It is composed mainly of water, extracellular polymeric substances (EPS), lipids, proteins, and DNA. Cyanobacteria form biofilms and have unique characteristics such as oxygenic photosynthesis, nitrogen fixation, excellent adaptability to various abiotic stress conditions, and the ability to secrete a variety of metabolites and hormones. This work focused on the characterization of the cyanobacterium Halomicronema sp. strain isolated from a brackish environment. This study included microscopic imaging, determination of phenolic content and antioxidant capacity, identification of chemicals interfering with biofilm formation, and transcriptomic analysis by RNA sequencing and real-time PCR. Gene expression analysis was centered on genes related to the production of EPS and biofilm-related transcription factors. This study led to the identification of wza1 and wzt as EPS biomarkers and luxR-05665, along with genes belonging to the TetR/AcrR and LysR families, as potential biomarkers useful for studying and monitoring biofilm formation under different environmental conditions. Moreover, this work revealed that Halomicronema sp. can grow even in the presence of strong abiotic stresses, such as high salt, and has good antioxidant properties.

", "keywords": ["570", "Extracellular Polymeric Substance Matrix", "Gene Expression Profiling", "Gene Expression Regulation", " Bacterial", "stress resilience", "Cyanobacteria", "cyanobacteria", "Article", "transcriptomics", "Bacterial Proteins", "Halomicronema sp", "Stress", " Physiological", "Biofilms", "biofilm formation", "EPS", "Transcriptome"]}, "links": [{"href": "https://doi.org/11381/3018373"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/International%20Journal%20of%20Molecular%20Sciences", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "11381/3018373", "name": "item", "description": "11381/3018373", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/11381/3018373"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-01-15T00:00:00Z"}}, {"id": "2907281909", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:25:52Z", "type": "Journal Article", "created": "2019-01-03", "title": "Polyphasic evaluation of key cyanobacteria in biocrusts from the most arid region in Europe", "description": "

Cyanobacteria are key microbes in topsoil communities that have important roles in preventing soil erosion, carbon and nitrogen fixation, and influencing soil hydrology. However, little is known regarding the identity and distribution of the microbial components in the photosynthetic assemblages that form a cohesive biological soil crust (biocrust) in drylands of Europe. In this study, we investigated the cyanobacterial species colonizing biocrusts in three representative dryland ecosystems from the most arid region in Europe (SE Spain) that are characterized by different soil conditions. Isolated cyanobacterial cultures were identified by a polyphasic approach, including 16S rRNA gene sequencing, phylogenetic relationship determination, and morphological and ecological habitat assessments. Three well-differentiated groups were identified: heterocystous-cyanobacteria (Nostoc commune,Nostoc calcicola,Tolypothrix distortaandScytonema hyalinum), which play an important role in N and C cycling in soil; nonheterocystous bundle-forming cyanobacteria (Microcoleus steenstrupii,Trichocoleus desertorum, andSchizothrixcf. calcicola); and narrow filamentous cyanobacteria (Leptolyngbya frigidaandOculatella kazantipica), all of which are essential genera for initial biocrust formation. The results of this study contribute to our understanding of cyanobacterial species composition in biocrusts from important and understudied European habitats, such as the Mediterranean Basin, a hotspot of biodiversity, where these species are keystone pioneer organisms.Cyanobacteria are key microbes in topsoil communities that have important roles in preventing soil erosion, carbon and nitrogen fixation, and influencing soil hydrology. However, little is known regarding the identity and distribution of the microbial components in the photosynthetic assemblages that form a cohesive biological soil crust (biocrust) in drylands of Europe. In this study, we investigated the cyanobacterial species colonizing biocrusts in three representative dryland ecosystems from the most arid region in Europe (SE Spain) that are characterized by different soil conditions. Isolated cyanobacterial cultures were identified by a polyphasic approach, including 16S rRNA gene sequencing, phylogenetic relationship determination, and morphological and ecological habitat assessments. Three well-differentiated groups were identified: heterocystous-cyanobacteria (Nostoc commune,Nostoc calcicola,Tolypothrix distortaandScytonema hyalinum), which play an important role in N and C cycling in soil; nonheterocystous bundle-forming cyanobacteria (Microcoleus steenstrupii,Trichocoleus desertorum, andSchizothrixcf. calcicola); and narrow filamentous cyanobacteria (Leptolyngbya frigidaandOculatella kazantipica), all of which are essential genera for initial biocrust formation. The results of this study contribute to our understanding of cyanobacterial species composition in biocrusts from important and understudied European habitats, such as the Mediterranean Basin, a hotspot of biodiversity, where these species are keystone pioneer organisms.

Photoautotrophic soil cyanobacteria play essential ecological roles and are known to exhibit large changes in their diversity and abundance throughout early succession. However, much less is known about how and why soil cyanobacterial communities change as soil develops over centuries and millennia, and the effects that vegetation have on such communities.

We combined an extensive field survey, including 16 global soil chronosequences across contrasting ecosystems (from deserts to tropical forests), with molecular analyses to investigate how the diversity and abundance of photosynthetic and nonphotosynthetic soil cyanobacteria are affected by vegetation change during soil development, over time periods from hundreds to thousands of years.

We show that, in most chronosequences, the abundance, species richness and community composition of soil cyanobacteria are relatively stable as soil develops (from centuries to millennia). Regardless of soil age, forest chronosequences were consistently dominated by nonphotosynthetic cyanobacteria (Vampirovibrionia), while grasslands and shrublands were dominated by photosynthetic cyanobacteria. Chronosequences undergoing drastic vegetation shifts (e.g. transitions from grasslands to forests) experienced significant changes in the composition of soil cyanobacterial communities.

Our results advance our understanding of the ecology of cyanobacterial classes, and of the understudied nonphotosynthetic cyanobacteria in particular, and highlight the key role of vegetation as a major driver of their temporal dynamics as soil develops.

Photoautotrophic soil cyanobacteria play essential ecological roles and are known to exhibit large changes in their diversity and abundance throughout early succession. However, much less is known about how and why soil cyanobacterial communities change as soil develops over centuries and millennia, and the effects that vegetation have on such communities.

We combined an extensive field survey, including 16 global soil chronosequences across contrasting ecosystems (from deserts to tropical forests), with molecular analyses to investigate how the diversity and abundance of photosynthetic and nonphotosynthetic soil cyanobacteria are affected by vegetation change during soil development, over time periods from hundreds to thousands of years.

We show that, in most chronosequences, the abundance, species richness and community composition of soil cyanobacteria are relatively stable as soil develops (from centuries to millennia). Regardless of soil age, forest chronosequences were consistently dominated by nonphotosynthetic cyanobacteria (Vampirovibrionia), while grasslands and shrublands were dominated by photosynthetic cyanobacteria. Chronosequences undergoing drastic vegetation shifts (e.g. transitions from grasslands to forests) experienced significant changes in the composition of soil cyanobacterial communities.

Our results advance our understanding of the ecology of cyanobacterial classes, and of the understudied nonphotosynthetic cyanobacteria in particular, and highlight the key role of vegetation as a major driver of their temporal dynamics as soil develops.

Cyanobacteria are key microbes in topsoil communities that have important roles in preventing soil erosion, carbon and nitrogen fixation, and influencing soil hydrology. However, little is known regarding the identity and distribution of the microbial components in the photosynthetic assemblages that form a cohesive biological soil crust (biocrust) in drylands of Europe. In this study, we investigated the cyanobacterial species colonizing biocrusts in three representative dryland ecosystems from the most arid region in Europe (SE Spain) that are characterized by different soil conditions. Isolated cyanobacterial cultures were identified by a polyphasic approach, including 16S rRNA gene sequencing, phylogenetic relationship determination, and morphological and ecological habitat assessments. Three well-differentiated groups were identified: heterocystous-cyanobacteria (Nostoc commune,Nostoc calcicola,Tolypothrix distortaandScytonema hyalinum), which play an important role in N and C cycling in soil; nonheterocystous bundle-forming cyanobacteria (Microcoleus steenstrupii,Trichocoleus desertorum, andSchizothrixcf. calcicola); and narrow filamentous cyanobacteria (Leptolyngbya frigidaandOculatella kazantipica), all of which are essential genera for initial biocrust formation. The results of this study contribute to our understanding of cyanobacterial species composition in biocrusts from important and understudied European habitats, such as the Mediterranean Basin, a hotspot of biodiversity, where these species are keystone pioneer organisms.A positive soil carbon (C)\uffe2\uff80\uff90climate feedback is embedded into the climatic models of the IPCC. However, recent global syntheses indicate that the temperature sensitivity of soil respiration (RS) in drylands, the largest biome on Earth, is actually lower in warmed than in control plots. Consequently, soil C losses with future warming are expected to be low compared with other biomes. Nevertheless, the empirical basis for these global extrapolations is still poor in drylands, due to the low number of field experiments testing the pathways behind the long\uffe2\uff80\uff90term responses of soil respiration (RS) to warming. Importantly, global drylands are covered with biocrusts (communities formed by bryophytes, lichens, cyanobacteria, fungi, and bacteria), and thus,RSresponses to warming may be driven by both autotrophic and heterotrophic pathways. Here, we evaluated the effects of 8\uffe2\uff80\uff90year experimental warming onRS, and the different pathways involved, in a biocrust\uffe2\uff80\uff90dominated dryland in southern Spain. We also assessed the overall impacts on soil organic C (SOC) accumulation over time. Across the years and biocrust cover levels, warming reducedRSby 0.30\uffc2\uffa0\uffce\uffbcmol\uffc2\uffa0CO2\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0s\uffe2\uff88\uff921(95% CI\uffc2\uffa0=\uffc2\uffa0\uffe2\uff88\uff920.24 to 0.84), although the negative warming effects were only significant after 3\uffc2\uffa0years of elevated temperatures in areas with low initial biocrust cover. We found support for different pathways regulating the warming\uffe2\uff80\uff90induced reduction inRSat areas with low (microbial thermal acclimation via reduced soil mass\uffe2\uff80\uff90specific respiration and \uffce\uffb2\uffe2\uff80\uff90glucosidase enzymatic activity) vs. high (microbial thermal acclimation jointly with a reduction in autotrophic respiration from decreased lichen cover) initial biocrust cover. Our 8\uffe2\uff80\uff90year experimental study shows a reduction in soil respiration with warming and highlights that biocrusts should be explicitly included in modeling efforts aimed to quantify the soil C\uffe2\uff80\uff93climate feedback in drylands. Due to their abilities to survive intense radiation and low water availability, hypersaline microbial mats are often suggested to be analogs of potential extraterrestrial life. However, even on Earth, the limitations imposed on microbial processes by saturation-level salinity have rarely been studied in situ .

Microbial life is surprisingly abundant and diverse in global desert ecosystems. In these environments, microorganisms endure a multitude of physicochemical stresses, including low water potential, carbon and nitrogen starvation, and extreme temperatures. In this review, we summarize our current understanding of the energetic mechanisms and trophic dynamics that underpin microbial function in desert ecosystems. Accumulating evidence suggests that dormancy is a common strategy that facilitates microbial survival in response to water and carbon limitation.

", "keywords": ["0301 basic medicine", "dormancy", "CYANOBACTERIAL EXOPOLYSACCHARIDES", "Trace gas", "Microbiology", "SOIL CRUSTS", "Energy reserve", "HIGH-AFFINITY", "03 medical and health sciences", "trace gas", "ATMOSPHERIC TRACE GASES", "Energetics", "energy reserve", "Dormancy", "SOR RONDANE MOUNTAINS", "Desert", "Photosynthesis", "106026 Ecosystem research", "CARBON-MONOXIDE", "desert", "ATACAMA DESERT", "energetics", "2. Zero hunger", "106022 Mikrobiologie", "0303 health sciences", "photosynthesis", "COMMUNITY RESPONSE", "15. Life on land", "QR1-502", "106026 \u00d6kosystemforschung", "DRY SOIL", "13. Climate action", "MOLECULAR-HYDROGEN", "106022 Microbiology", "Minireview"]}, "links": [{"href": "https://journals.asm.org/doi/pdf/10.1128/mSystems.00495-19"}, {"href": "https://doi.org/2263/74486"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/mSystems", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "2263/74486", "name": "item", "description": "2263/74486", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/2263/74486"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-04-28T00:00:00Z"}}, {"id": "3211211158", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:26:18Z", "type": "Journal Article", "created": "2021-10-26", "title": "Extreme freeze-thaw cycles do not affect moss-associated nitrogen fixation across a temperature gradient, but affect nutrient loss from mosses", "description": "Abstract Moss-associated nitrogen (N2) fixation performed by epiphytic, N2-fixing bacteria (diazotrophs) contributes significantly to ecosystem N input in pristine habitats. While we have some understanding of the effects of climate warming on moss-associated N2 fixation, we lack data on effects of freeze-thaw cycles (FTCs) on diazotroph activity, although increased frequency of FTCs is predicted. We collected the widespread moss Pleurozium schreberi along a climate gradient (temperate, boreal, arctic) and exposed moss and associated diazotrophs to severe (20\u00a0\u00b0C difference, cycling between +10 and \u221210\u00a0\u00b0C) and mild (6\u00a0\u00b0C difference, \u00b13\u00a0\u00b0C) diurnal FTCs. We measured N2 fixation in mosses over 8 weeks and assessed their nutrient loss (fixed N2, total dissolved N, ammonium, phosphate) during the FTCs. We expected lower nitrogenase activity in mosses exposed to more severe FTCs and different sensitivities of N2 fixation towards FTCs along the climate gradient. However, no differences were found in N2 fixation between mild and severe FTCs, but N2 fixation in mosses from the temperate heath was less susceptible to FTCs than those from colder sites, suggesting adapted temperate diazotroph communities. Mosses lost little N, most at constant, positive temperatures, while more phosphate was lost from mosses exposed to FTCs, depending on the positioning along the climate gradient, mirroring nutrient demand and limitation. Our results show that moss-associated N2 fixation is less susceptible towards FTCs than expected but nutrient loss from moss carpets can increase following FTCs, with consequences for nutrient pools and fluxes.", "keywords": ["0106 biological sciences", "Diazotrophs", "13. Climate action", "Nutrient limitation", "Climate change", "0401 agriculture", " forestry", " and fisheries", "Phosphorus", "04 agricultural and veterinary sciences", "15. Life on land", "Cyanobacteria", "Acetylene reduction", "01 natural sciences"]}, "links": [{"href": "https://doi.org/3211211158"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Acta%20Oecologica", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "3211211158", "name": "item", "description": "3211211158", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/3211211158"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-01T00:00:00Z"}}, {"id": "3212783076", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:26:18Z", "type": "Journal Article", "created": "2021-11-08", "title": "Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It", "description": "Abstract

Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha\u22121 yr\u22121) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha\u22121 yr\u22121) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

", "keywords": ["0301 basic medicine", "0303 health sciences", "03 medical and health sciences", "Sphagnum", "Nitrogen fixation", "Nitrogen pollution", "Organic nitrogen", "15. Life on land", "Cyanobacteria", "Feathermosses"]}, "links": [{"href": "https://doi.org/3212783076"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "3212783076", "name": "item", "description": "3212783076", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/3212783076"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-08T00:00:00Z"}}, {"id": "35687087", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:26:26Z", "type": "Journal Article", "created": "2022-06-10", "title": "Biotic and abiotic controls of nitrogen fixation in cyanobacteria\u2013moss associations", "description": "Summary

Most mosses are colonized by nitrogen (N)\uffe2\uff80\uff90fixing cyanobacteria. This discovery is relatively recent, which can explain the large knowledge gaps the field is now tackling. For instance, while we have a good understanding of the abiotic controls (e.g. nutrient availability, increased temperature), we still do not know much about the biotic controls of N2 fixation in mosses. I propose here that we should endeavour to position moss\uffe2\uff80\uff93cyanobacteria associations along the mutualism\uffe2\uff80\uff93parasitism continuum under varying abiotic conditions (e.g. nutrient availability). This would finally unravel the nature of the relationship between the partners and will be a big leap in our understanding of the evolution of plant\uffe2\uff80\uff93bacteria interactions using moss\uffe2\uff80\uff93cyanobacteria associations as a model system.

Tropical cloud forests are characterized by abundant and biodiverse mosses which grow epiphytically as well as on the ground. Nitrogen (N)-fixing cyanobacteria live in association with most mosses, and contribute greatly to the N pool via biological nitrogen fixation (BNF). However, the availability of nutrients, especially N and phosphorus (P), can influence BNF rates drastically. To evaluate the effects of increased N and P availability on BNF in mosses, we conducted a laboratory experiment where we added N and P, in isolation and combined, to three mosses (Campylopus sp., Dicranum sp. and Thuidium peruvianum) collected from a cloud forest in Peru. Our results show that N addition almost completely inhibited BNF within a day, whereas P addition caused variable results across moss species. Low N2 fixation rates were observed in Campylopus sp. across the experiment. BNF in Dicranum sp. was decreased by all nutrients, while P additions seemed to promote BNF in T. peruvianum. Hence, each of the three mosses contributes distinctively to the ecosystem N pool depending on nutrient availability. Moreover, increased N input will likely significantly decrease BNF associated with mosses also in tropical cloud forests, thereby limiting N input to these ecosystems via the moss-cyanobacteria pathway.

", "keywords": ["nutrient limitation", "cyanobacteria; ecosystem ecology; global change; mosses; nitrogen fixation; nutrient limitation; phosphorus; tropical cloud forest", "Botany", "ecosystem ecology", "15. Life on land", "Milj\u00f6vetenskap", "cyanobacteria", "Article", "mosses", "13. Climate action", "nitrogen fixation", "QK1-989", "tropical cloud forest", "phosphorus", "Environmental Sciences", "global change"]}, "links": [{"href": "http://www.mdpi.com/2223-7747/12/7/1443/pdf"}, {"href": "https://www.mdpi.com/2223-7747/12/7/1443/pdf"}, {"href": "https://doi.org/PMC10097241"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plants", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "PMC10097241", "name": "item", "description": "PMC10097241", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/PMC10097241"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2023-03-24T00:00:00Z"}}, {"id": "PMC10907420", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:28:16Z", "type": "Journal Article", "created": "2024-03-01", "title": "The Feather Moss Hylocomium splendens Affects the Transcriptional Profile of a Symbiotic Cyanobacterium in Relation to Acquisition and Turnover of Key Nutrients", "description": "Abstract

Moss-cyanobacteria symbioses were proposed to be based on nutrient exchange, with hosts providing C and S while bacteria provide N, but we still lack understanding of the underlying molecular mechanisms of their interactions. We investigated how contact between the ubiquitous moss Hylocomium splendens and its cyanobiont affects nutrient-related gene expression of both partners. We isolated a cyanobacterium from H. splendens and co-incubated it with washed H. splendens shoots. Cyanobacterium and moss were also incubated separately. After 1\uffc2\uffa0week, we performed acetylene reduction assays to estimate N2 fixation and RNAseq to evaluate metatranscriptomes. Genes related to N2 fixation and the biosynthesis of several amino acids were up-regulated in the cyanobiont when hosted by the moss. However, S-uptake and the biosynthesis of the S-containing amino acids methionine and cysteine were down-regulated in the cyanobiont while the degradation of selenocysteine was up-regulated. In contrast, the number of differentially expressed genes in the moss was much lower, and almost no transcripts related to nutrient metabolism were affected. It is possible that, at least during the early stage of this symbiosis, the cyanobiont receives few if any nutrients from the host in return for N, suggesting that moss\uffe2\uff80\uff93cyanobacteria symbioses encompass relationships that are more plastic than a constant mutualist flow of nutrients.