| 1. |
- Hamard, Samuel, et al.
(författare)
-
Contribution of microbial photosynthesis to peatland carbon uptake along a latitudinal gradient
- 2021
-
Ingår i: Journal of Ecology. - : British Ecological Society. - 0022-0477 .- 1365-2745. ; 109:9, s. 3424-3441
-
Tidskriftsartikel (refereegranskat)abstract
- Phototrophic microbes, also known as micro-algae, display a high abundance in many terrestrial surface soils. They contribute to atmospheric carbon dioxide fluxes through their photosynthesis, and thus regulate climate similar to plants. However, microbial photosynthesis remains overlooked in most terrestrial ecosystems. Here, we hypothesise that phototrophic microbes significantly contribute to peatland C uptake, unless environmental conditions limit their development and their photosynthetic activity. To test our hypothesis, we studied phototrophic microbial communities in five peatlands distributed along a latitudinal gradient in Europe. By means of metabarcoding, microscopy and cytometry analyses, as well as measures of photosynthesis, we investigated the diversity, absolute abundance and photosynthetic rates of the phototrophic microbial communities. We identified 351 photosynthetic prokaryotic and eukaryotic operational taxonomic units (OTUs) across the five peatlands. We found that water availability and plant composition were important determinants of the composition and the structure of phototrophic microbial communities. Despite environmental shifts in community structure and composition, we showed that microbial C fixation rates remained similar along the latitudinal gradient. Our results further revealed that phototrophic microbes accounted for approximately 10% of peatland C uptake. Synthesis. Our findings show that phototrophic microbes are extremely diverse and abundant in peatlands. While species turnover with environmental conditions, microbial photosynthesis similarly contributed to peatland C uptake at all latitudes. We estimate that phototrophic microbes take up around 75 MT CO2 per year in northern peatlands. This amount roughly equals the magnitude of projected peatland C loss due to climate warming and highlights the importance of phototrophic microbes for the peatland C cycle.
|
|
| 2. |
- Sytiuk, Anna, et al.
(författare)
-
Biochemical traits enhance the trait concept in Sphagnum ecology
- 2022
-
Ingår i: Oikos. - : John Wiley & Sons. - 0030-1299 .- 1600-0706. ; :4
-
Tidskriftsartikel (refereegranskat)abstract
- Sphagnum mosses are key to northern peatland carbon sequestration. They have a range of morphological and anatomical characteristics that allow them to cope with environmental stress. Sphagnum also produces a plethora of biochemicals that may prevent stress-induced cell-damage. However, the linkages between Sphagnum anatomical, morphological and biochemical traits (i.e. metabolites, pigments and antioxidant enzyme activities) are poorly known, neither are their joint responses to environmental change. Here, we quantify and link an array of Sphagnum anatomical, morphological and biochemical traits in five Sphagnum-dominated peatlands distributed along a latitudinal gradient in Europe, covering a range of regional and local environmental conditions. Sphagnum morphological and anatomical traits were intrinsically linked to Sphagnum metabolites and enzyme activities, and these relationships were driven by shared responses to local and regional environmental factors. More particularly, we found that Sphagnum traits can be grouped into four clusters related to growth, biomass, defense and water stress tolerance. We used regional and local environmental conditions data to further show that biochemicals and their specific linkages with some morphological traits describe dimensions of physiology not captured by anatomical and morphological traits alone. These results suggest that Sphagnum morphology and function is rooted in the metabolome, and that incorporating biochemicals into the functional trait space concept can enhance our mechanistic understanding and predictive power in Sphagnum ecology.
|
|
| 3. |
- Sytiuk, Anna, et al.
(författare)
-
Linkages between Sphagnum metabolites and peatland CO2 uptake are sensitive to seasonality in warming trends
- 2023
-
Ingår i: New Phytologist. - : John Wiley & Sons. - 0028-646X .- 1469-8137. ; 237:4, s. 1164-1178
-
Tidskriftsartikel (refereegranskat)abstract
- Plants produce a wide diversity of metabolites. Yet, our understanding of how shifts in plant metabolites as a response to climate change feedback on ecosystem processes remains scarce. Here, we test to what extent climate warming shifts the seasonality of metabolites produced by Sphagnum mosses, and what are the consequences of these shifts for peatland C uptake.We used a reciprocal transplant experiment along a climate gradient in Europe to simulate climate change. We evaluated the responses of primary and secondary metabolites in five Sphagnum species and related their responses to gross ecosystem productivity (GEP).When transplanted to a warmer climate, Sphagnum species showed consistent responses to warming, with an upregulation of either their primary or secondary metabolite according to seasons. Moreover, these shifts were correlated to changes in GEP, especially in spring and autumn.Our results indicate that the Sphagnum metabolome is very plastic and sensitive to warming. We also show that warming-induced changes in the seasonality of Sphagnum metabolites have consequences on peatland GEP. Our findings demonstrate the capacity for plant metabolic plasticity to impact ecosystem C processes and reveal a further mechanism through which Sphagnum could shape peatland responses to climate change.
|
|
| 4. |
- Sytiuk, Anna, et al.
(författare)
-
Predicting the structure and functions of peatland microbial communities from Sphagnum phylogeny, anatomical and morphological traits and metabolites
- 2022
-
Ingår i: Journal of Ecology. - : John Wiley & Sons. - 0022-0477 .- 1365-2745. ; 110:1, s. 80-96
-
Tidskriftsartikel (refereegranskat)abstract
- Sphagnum mosses are keystone species in northern peatlands. Notably, they play an important role in peatland carbon (C) cycling by regulating the composition and activity of microbial communities. However, it remains unclear whether information on Sphagnum phylogeny and/or traits-based composition (i.e. anatomical and morphological traits and metabolites) can be used to predict the structure of microbial communities and their functioning. Here we evaluated whether Sphagnum phylogeny and traits predict additional variation in peatland microbial community composition and functioning beyond what would be predicted from environmental characteristics (i.e. climatic and edaphic conditions).We collected Sphagnum and microbial data from five European peatlands distributed along a latitudinal gradient from northern Sweden to southern France. These data allowed us to assess Sphagnum anatomical and morphological traits and metabolites at different sites along changing environmental conditions. Using structural equation modelling (SEM) and phylogenetic distance analyses, we investigated the role of Sphagnum traits in shaping microbial community composition and functioning along with environmental conditions.We show that microbial community composition and traits varied independently from both Sphagnum phylogeny and the latitudinal gradient. Specifically, the addition of Sphagnum traits to climatic and edaphic variables to the SEM allowed it to explain a larger proportion of the explained variance (R2). This observation was most apparent for the biomass of decomposers (+42%) and phototrophs (+19%), as well as for growth yield microbial traits (+10%). As such, that Sphagnum metabolites were important drivers for microbial community structure and traits, while Sphagnum anatomical and morphological traits were poor predictors.Synthesis. Our results highlight that Sphagnum metabolites are more likely to influence peatland microbial food web structure and functioning than Sphagnum anatomical and morphological traits. We provide further evidence that measurements of the plant metabolome, when combined with classical functional traits, improve our understanding of how the plants interact with their associated microbiomes.
|
|
