The influence of shoot density on the soil moisture content of non-sorted circles in relation to ... more The influence of shoot density on the soil moisture content of non-sorted circles in relation to frost heave activity: a comparison between a species from frost-disturbed sites (Tofieldia pusilla) and a species from stable ground (Calamagrostis lapponica)
Modern microbial and ecosystem sciences require diverse interdisciplinary teams that are often ch... more Modern microbial and ecosystem sciences require diverse interdisciplinary teams that are often challenged in “speaking” to one another due to different languages and data product types. Here we introduce the IsoGenie Database (IsoGenieDB; https://isogenie-db.asc.ohio-state.edu/), a de novo developed data management and exploration platform, as a solution to this challenge of accurately representing and integrating heterogenous environmental and microbial data across ecosystem scales. The IsoGenieDB is a public and private data infrastructure designed to store and query data generated by the IsoGenie Project, a ~10 year DOE-funded project focused on discovering ecosystem climate feedbacks in a thawing permafrost landscape. The IsoGenieDB provides (i) a platform for IsoGenie Project members to explore the project’s interdisciplinary datasets across scales through the inherent relationships among data entities, (ii) a framework to consolidate and harmonize the datasets needed by the te...
Considerable progress has been made in ecological and evolutionary genetics with studies demonstr... more Considerable progress has been made in ecological and evolutionary genetics with studies demonstrating how genes underlying plant and microbial traits can influence adaptation and even 'extend' to influence community structure and ecosystem level processes. Progress in this area is limited to model systems with deep genetic and genomic resources that often have negligible ecological impact or interest. Thus, important linkages between genetic adaptations and their consequences at organismal and ecological scales are often lacking. Here we introduce the Sphagnome Project, which incorporates genomics into a long-running history of Sphagnum research that has documented unparalleled contributions to peatland ecology, carbon sequestration, biogeochemistry, microbiome research, niche construction, and ecosystem engineering. The Sphagnome Project encompasses a genus-level sequencing effort that represents a new type of model system driven not only by genetic tractability, but by ec...
Research on permafrost carbon has dramatically increased in the past few years. A new estimate of... more Research on permafrost carbon has dramatically increased in the past few years. A new estimate of 1672 Pg C of belowground organic carbon in the northern circumpolar permafrost region more than doubles the previous value and highlights the potential role of permafrost carbon in the Earth System. Uncertainties in this new estimate remain due to relatively few available pedon data for certain geographic sectors and the deeper cryoturbated soil horizons, and the large polygon size in the soil maps used for upscaling. The large permafrost carbon pool is not equally distributed across the landscape: peat deposits, cryoturbated soils and the loess‐like deposits of the yedoma complex contain disproportionately large amounts of soil organic matter, often exhibiting a low degree of decomposition. Recent findings in Alaska and northern Sweden provide strong evidence that the deeper soil carbon in permafrost terrain is starting to be released, supporting previous reports from Siberia. The perm...
Many of the world's northern peatlands are underlain by rapidly thawing permafrost. Because p... more Many of the world's northern peatlands are underlain by rapidly thawing permafrost. Because plant production in these peatlands is often nitrogen (N)‐limited, a release of N stored in permafrost may stimulate net primary production or change species composition if it is plant‐available. In this study, we aimed to quantify plant‐available N in thawing permafrost soils of subarctic peatlands. We compared plant‐available N‐pools and ‐fluxes in near‐surface permafrost (0–10 cm below the thawfront) to those taken from a current rooting zone layer (5–15 cm depth) across five representative peatlands in subarctic Sweden. A range of complementary methods was used: extractions of inorganic and organic N, inorganic and organic N‐release measurements at 0.5 and 11 °C (over 120 days, relevant to different thaw‐development scenarios) and a bioassay with Poa alpina test plants. All extraction methods, across all peatlands, consistently showed up to seven times more plant‐available N in near‐s...
Summary Vascular plant growth forms in northern peatlands differ in their strategies to cope with... more Summary Vascular plant growth forms in northern peatlands differ in their strategies to cope with the harsh climate, low nutrient availability and progressively increasing height of the Sphagnum carpet in which they grow. Climate change may therefore affect growth forms differentially, both directly and through changes in the length growth of Sphagnum mosses. However, the role of mosses as modifiers of climate‐change effects on vascular plants has been largely overlooked so far. We investigated the direct and Sphagnum‐mediated effects of experimental changes in summer, winter and spring climate on four species of contrasting growth forms (evergreen and deciduous shrubs, graminoid, forb) in a subarctic bog, by studying their biomass and nitrogen losses through leaf litter, and the length growth of the two shrubs. Direct and indirect effects of summer warming differed among the growth forms. Enhanced Sphagnum overgrowth of leaves due to summer warming initially stimulated leaf litter ...
Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as... more Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition rates, we brought together leaf trait and litter mass loss data for 818 species from 66 decomposition experiments on six continents. We show that: (i) the magnitude of species‐driven differences is much larger than previously thought and greater than climate‐driven variation; (ii) the decomposability of a species’ litter is consistently correlated with that species’ ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling. This connection between plant strategies and decomposability is crucial for both understanding vegetation–soil feedbacks, and for improving forecasts of the global carbon cycle.
ABSTRACT Background/Question/Methods Thawing of permafrost soils affects many northern peatlands,... more ABSTRACT Background/Question/Methods Thawing of permafrost soils affects many northern peatlands, where one-third of the world’s soil organic carbon is stored due to their high ratio of carbon assimilation to carbon mineralization. Because plant production in these peatlands is often nitrogen (N)-limited, a release of permafrost N upon thawing may likely stimulate net primary production or change species composition. However, surprisingly little is known about plant-availability and plant-uptake of nitrogen stored in permafrost soils. We quantified plant-available N in thawing permafrost soils of subarctic peatlands and found up to seven times more plant-available N in near-surface permafrost soil compared to the current rooting zone layer. With the work presented here, we aimed to identify the potential impact of this increased N-availability due to thawing permafrost on subarctic peatland plant production and species composition. We compared this impact with the effect of increased nutrient availability in shallower layers (e.g. in relation to enhanced N-mineralization due to climatic warming). Therefore, we supplied 15N-labelled nitrogen at the thaw front and performed a 3-year full-factorial belowground fertilization experiment with deep-fertilization at the thaw front at 45 cm depth and shallow-fertilization at 10 cm depth. Results/Conclusions We found that only particular species (e.g. Rubus chamaemorus) have active roots at the thaw front. Further, if presented with increased nitrogen at the thaw front, these species had higher aboveground biomass and N-content, whereas this was not the case for shallower-rooting species (e.g. E. hermaphroditum and Andromeda polifolia). Moreover, the effects of increased nutrient availability at the thaw front on total aboveground biomass production were similar in magnitude to the effects of increased nutrient availability in shallower layers. Nutrient limitation of plant growth in subarctic peatlands appeared to be strong enough for the effects of increased deep and shallow nutrient availability on biomass production to be additive. Altogether, these results show that plant-available N released from thawing permafrost can be considered a true ‘new’ N source for deep-rooting sub-arctic plant species, which will increase their biomass production. As this is not the case for shallow-rooting species, the release of plant-available N from thawing permafrost has the potential to alter species composition on the long-term by benefitting specific deep-rooting species only.
The influence of shoot density on the soil moisture content of non-sorted circles in relation to ... more The influence of shoot density on the soil moisture content of non-sorted circles in relation to frost heave activity: a comparison between a species from frost-disturbed sites (Tofieldia pusilla) and a species from stable ground (Calamagrostis lapponica)
Modern microbial and ecosystem sciences require diverse interdisciplinary teams that are often ch... more Modern microbial and ecosystem sciences require diverse interdisciplinary teams that are often challenged in “speaking” to one another due to different languages and data product types. Here we introduce the IsoGenie Database (IsoGenieDB; https://isogenie-db.asc.ohio-state.edu/), a de novo developed data management and exploration platform, as a solution to this challenge of accurately representing and integrating heterogenous environmental and microbial data across ecosystem scales. The IsoGenieDB is a public and private data infrastructure designed to store and query data generated by the IsoGenie Project, a ~10 year DOE-funded project focused on discovering ecosystem climate feedbacks in a thawing permafrost landscape. The IsoGenieDB provides (i) a platform for IsoGenie Project members to explore the project’s interdisciplinary datasets across scales through the inherent relationships among data entities, (ii) a framework to consolidate and harmonize the datasets needed by the te...
Considerable progress has been made in ecological and evolutionary genetics with studies demonstr... more Considerable progress has been made in ecological and evolutionary genetics with studies demonstrating how genes underlying plant and microbial traits can influence adaptation and even 'extend' to influence community structure and ecosystem level processes. Progress in this area is limited to model systems with deep genetic and genomic resources that often have negligible ecological impact or interest. Thus, important linkages between genetic adaptations and their consequences at organismal and ecological scales are often lacking. Here we introduce the Sphagnome Project, which incorporates genomics into a long-running history of Sphagnum research that has documented unparalleled contributions to peatland ecology, carbon sequestration, biogeochemistry, microbiome research, niche construction, and ecosystem engineering. The Sphagnome Project encompasses a genus-level sequencing effort that represents a new type of model system driven not only by genetic tractability, but by ec...
Research on permafrost carbon has dramatically increased in the past few years. A new estimate of... more Research on permafrost carbon has dramatically increased in the past few years. A new estimate of 1672 Pg C of belowground organic carbon in the northern circumpolar permafrost region more than doubles the previous value and highlights the potential role of permafrost carbon in the Earth System. Uncertainties in this new estimate remain due to relatively few available pedon data for certain geographic sectors and the deeper cryoturbated soil horizons, and the large polygon size in the soil maps used for upscaling. The large permafrost carbon pool is not equally distributed across the landscape: peat deposits, cryoturbated soils and the loess‐like deposits of the yedoma complex contain disproportionately large amounts of soil organic matter, often exhibiting a low degree of decomposition. Recent findings in Alaska and northern Sweden provide strong evidence that the deeper soil carbon in permafrost terrain is starting to be released, supporting previous reports from Siberia. The perm...
Many of the world's northern peatlands are underlain by rapidly thawing permafrost. Because p... more Many of the world's northern peatlands are underlain by rapidly thawing permafrost. Because plant production in these peatlands is often nitrogen (N)‐limited, a release of N stored in permafrost may stimulate net primary production or change species composition if it is plant‐available. In this study, we aimed to quantify plant‐available N in thawing permafrost soils of subarctic peatlands. We compared plant‐available N‐pools and ‐fluxes in near‐surface permafrost (0–10 cm below the thawfront) to those taken from a current rooting zone layer (5–15 cm depth) across five representative peatlands in subarctic Sweden. A range of complementary methods was used: extractions of inorganic and organic N, inorganic and organic N‐release measurements at 0.5 and 11 °C (over 120 days, relevant to different thaw‐development scenarios) and a bioassay with Poa alpina test plants. All extraction methods, across all peatlands, consistently showed up to seven times more plant‐available N in near‐s...
Summary Vascular plant growth forms in northern peatlands differ in their strategies to cope with... more Summary Vascular plant growth forms in northern peatlands differ in their strategies to cope with the harsh climate, low nutrient availability and progressively increasing height of the Sphagnum carpet in which they grow. Climate change may therefore affect growth forms differentially, both directly and through changes in the length growth of Sphagnum mosses. However, the role of mosses as modifiers of climate‐change effects on vascular plants has been largely overlooked so far. We investigated the direct and Sphagnum‐mediated effects of experimental changes in summer, winter and spring climate on four species of contrasting growth forms (evergreen and deciduous shrubs, graminoid, forb) in a subarctic bog, by studying their biomass and nitrogen losses through leaf litter, and the length growth of the two shrubs. Direct and indirect effects of summer warming differed among the growth forms. Enhanced Sphagnum overgrowth of leaves due to summer warming initially stimulated leaf litter ...
Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as... more Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition rates, we brought together leaf trait and litter mass loss data for 818 species from 66 decomposition experiments on six continents. We show that: (i) the magnitude of species‐driven differences is much larger than previously thought and greater than climate‐driven variation; (ii) the decomposability of a species’ litter is consistently correlated with that species’ ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling. This connection between plant strategies and decomposability is crucial for both understanding vegetation–soil feedbacks, and for improving forecasts of the global carbon cycle.
ABSTRACT Background/Question/Methods Thawing of permafrost soils affects many northern peatlands,... more ABSTRACT Background/Question/Methods Thawing of permafrost soils affects many northern peatlands, where one-third of the world’s soil organic carbon is stored due to their high ratio of carbon assimilation to carbon mineralization. Because plant production in these peatlands is often nitrogen (N)-limited, a release of permafrost N upon thawing may likely stimulate net primary production or change species composition. However, surprisingly little is known about plant-availability and plant-uptake of nitrogen stored in permafrost soils. We quantified plant-available N in thawing permafrost soils of subarctic peatlands and found up to seven times more plant-available N in near-surface permafrost soil compared to the current rooting zone layer. With the work presented here, we aimed to identify the potential impact of this increased N-availability due to thawing permafrost on subarctic peatland plant production and species composition. We compared this impact with the effect of increased nutrient availability in shallower layers (e.g. in relation to enhanced N-mineralization due to climatic warming). Therefore, we supplied 15N-labelled nitrogen at the thaw front and performed a 3-year full-factorial belowground fertilization experiment with deep-fertilization at the thaw front at 45 cm depth and shallow-fertilization at 10 cm depth. Results/Conclusions We found that only particular species (e.g. Rubus chamaemorus) have active roots at the thaw front. Further, if presented with increased nitrogen at the thaw front, these species had higher aboveground biomass and N-content, whereas this was not the case for shallower-rooting species (e.g. E. hermaphroditum and Andromeda polifolia). Moreover, the effects of increased nutrient availability at the thaw front on total aboveground biomass production were similar in magnitude to the effects of increased nutrient availability in shallower layers. Nutrient limitation of plant growth in subarctic peatlands appeared to be strong enough for the effects of increased deep and shallow nutrient availability on biomass production to be additive. Altogether, these results show that plant-available N released from thawing permafrost can be considered a true ‘new’ N source for deep-rooting sub-arctic plant species, which will increase their biomass production. As this is not the case for shallow-rooting species, the release of plant-available N from thawing permafrost has the potential to alter species composition on the long-term by benefitting specific deep-rooting species only.
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Papers by E. Dorrepaal