Kate Buckeridge

Luxembourg Institute of Science and Technology (LIST) | LIST · Environmental Research & Innovation (ERIN)

Microbial necromass is an important source and component of soil organic matter (SOM), especially within the most stable pools. Global change factors such as anthropogenic nitrogen (N), phosphorus (P), and potassium (K) inputs, climate warming, elevated atmospheric carbon dioxide (eCO2 ), and periodic precipitation reduction (drought) strongly affe...

In mesic regions, where water availability is rarely limiting, temperature increases with climate change can prompt increases in primary production. These responses will be determined in part by nitrogen (N) and phosphorus (P) availability, yet the relative importance of N- versus P-cycling for supporting primary production and soil C is unclear. P...

Climate change currently manifests in upward and northward shifting treelines, which encompasses changes to the carbon (C) and nitrogen (N) composition of organic inputs to soils. Whether these changed inputs will increase or decrease microbial mineralisation of native soil organic matter remains unknown, making it difficult to estimate how treelin...

Microbial necromass is an important component of soil organic matter, however its persistence and contribution to soil carbon sequestration are poorly quantified. Here, we investigate the interaction of necromass with soil minerals and compare its persistence to that of plant litter in grassland soils under low- and high-management intensity in nor...

In high altitudes and high latitudes climate change manifests in upward and northward shifting treelines. This entails changes to the carbon (C) and nitrogen (N) composition of organic inputs to soils and can increase or decrease microbial mineralisation of native soil organic matter (positive or negative priming effect). It is currently unknown wh...

Microbial necromass is a large, dynamic and persistent component of soil organic carbon, the dominant terrestrial carbon pool. Quantification of necromass carbon stocks and its susceptibility to global change is becoming standard practice in soil carbon research. However, the typical proxies used for necromass carbon do not reveal the dynamic natur...

Phosphorus (P) limits or co‐limits plant and microbial life in multiple ecosystems, including the arctic tundra. Although current global carbon (C) models focus on the coupling between soil nitrogen (N) and C, ecosystem P response to climate warming may also influence the global C cycle. Permafrost soils may see enhanced or reduced P availability u...

There is an emerging consensus that microbial necromass carbon is the primary constituent of stable soil carbon, yet the controls on the stabilization process are unknown. Prior to stabilization, microbial necromass may be recycled by the microbial community. We propose that the efficiency of this recycling is a critical determinant of soil carbon...

Production and reduction of nitrous oxide (N2O) by soil denitrifiers influence atmospheric concentrations of this potent greenhouse gas. Accurate projections of the net N2O flux have three key uncertainties: (1) short- vs. long-term responses to warming, (2) interactions among soil horizons, and (3) temperature responses of different steps in the d...

Microbial necromass dominates soil organic matter. Recent research on necromass and soil carbon storage has focused on necromass production and stabilization mechanisms but not on the mechanisms of necromass retention. We present evidence from soil incubations with stable-isotope labeled necromass that abiotic adsorption may be more important than...

Microbial homeostasis—constant microbial element ratios along resource gradients—is a core ecological tenet, yet not all systems display homeostasis. We suggest investigations of homeostasis mechanisms must also consider plant–microbial interactions. Specifically, we hypothesized that ecosystems with strong plant community plasticity to changing re...

Production and reduction of nitrous oxide (N2O) by soil denitrifiers influences atmospheric concentrations of this potent greenhouse gas. Accurate climate projections of net N2O flux have three key uncertainties: (1) short- vs. long-term responses to warming; (2) interactions among soil horizons; and (3) temperature responses of different steps in...

Global change in the Arctic promotes deeper soil thaw and enhanced soil microbial activity, increasing nitrogen (N) and phosphorus (P) availability to plants and microbes in strongly nutrient‐limited ecosystems. This critical, positive climate feedback has been examined through fertilization experiments that describe short‐term (<10 yr) above‐ or b...

Accurate representation of temperature sensitivity (Q10) of soil microbial activity across time is critical for projecting soil CO2 efflux. Because microorganisms mediate soil carbon

Soil microorganisms act as gatekeepers for soil-atmosphere carbon exchange by balancing the accumulation and release of soil organic matter. However, poor understanding of the mechanisms responsible hinders the development of effective land management strategies to enhance soil carbon storage. Here we empirically test the link between microbial eco...

Soil microorganisms vary in the efficiency with which they convert soil organic matter carbon to stable biomass products. This carbon use efficiency (CUE) influences carbon budgets and is used in models to predict soil feedbacks to climate and land use intensity (LUI). Because LUI has the potential to alter soil microbial community structure and fu...

Rapid arctic vegetation change as a result of global warming includes an increase in the cover and biomass of deciduous shrubs. Increases in shrub abundance will result in a proportional increase of shrub litter in the litter community, potentially affecting carbon turnover rates in arctic ecosystems. We investigated the effects of leaf and root li...

Leachate from litter and vegetation penetrates permafrost surface soils during thaw before being exported to aquatic systems. We know this leachate is critical to ecosystem function downstream and hypothesized that thaw leachate inputs would also drive terrestrial microbial activity and nutrient uptake. However, we recognized two potential endpoint...

Background/Question/Methods Arctic warming has increased the density and cover of deciduous shrubs, which has global, regional and local implications for feedbacks to further climate warming. Enhanced deciduous shrub growth increases litter quantity and is believed to reduce litter quality. Increasing amounts of deciduous shrub litter could resul...

a b s t r a c t Soil microorganisms are critical to carbon and nutrient fluxes in terrestrial ecosystems. Understanding the annual pattern of soil microbial community structure and how it corresponds to soil nutrient availability and plant production is a fundamental first step towards being able to predict impacts of environmental change on ecosys...

Background/Question/Methods Arctic soils store large pools of carbon (C) that are sensitive to a warming climate. When upland permafrost thaws, soil organic matter, C and nutrients are mobilized by the resulting landscape erosion. Ecosystem recovery in the short-term (~ 50 y) is characterized by strongly enhanced above-ground biomass (shrubbiness...

Background/Question/Methods Arctic warming promotes permafrost degradation and thaw. Formerly frozen soils destabilize, leading to hillslope thermokarst failures, which erode organic matter from terrestrial ecosystems. Thermokarst failures are abundant and appear to have become more numerous in northern Alaska. This study is part of an ongoing la...

Pulses of plant-available nutrients to the soil solution are expected to occur during the dynamic winter–spring transition in arctic tundra. Our aims were to quantify the magnitude of these potential nutrient pulses, to understand the sensitivity of these pulses to winter conditions, and to characterize and integrate the environmental and biogeoche...

Air temperature freeze–thaw cycles often occur during the early spring period directly after snowmelt and before budbreak in low arctic tundra. This early spring period may be associated with nitrogen (N) and carbon (C) loss from soils as leachate or as trace gases, due to the detrimental impact of soil freeze–thaw cycles and a developing active la...

The importance of the fall, winter and spring periods to ecosystem functioning and biogeochemical cycling in tundra has only become apparent in the past two decades. Our research group has been conducting winter climate change-related studies at a low arctic tundra site near Daring Lake, north of Yellowknife in northern Canada for the past five yea...

Background/Question/Methods Microbial community seasonal succession may have large impacts on soil biogeochemical dynamics, in particular via the release of nutrients stored in the microbial cytoplasm or changes to microbial functional groups during spring thaw. The spring flush of nutrients at thaw is important for plant growth in many ecosystems...

Shrub growth has increased across the Arctic in recent decades and is strongly limited by soil nitrogen (N) availability. In order to understand the role of N in controlling shrub growth, we compared N-cycling in tall birch (Betula glandulosa) and surrounding dwarf birch hummock vegetation on similar soils in a Canadian low arctic site. Stable isot...

Microbial activity in the long arctic cold season is low but cumulatively important. In particular, the size of the microbial biomass and soil solution nutrient pool at the end of winter may control the quantity of nutrients available to plants in the following spring. Microbial starvation and lysis as a result of increasingly severe soluble carbon...

Plant and microbial nitrogen (N) dynamics were examined in soils of an Arctic salt marsh beneath goose‐grazed swards and in degraded soils. The degraded soils are the outcome of intensive destructive foraging by geese, which results in vegetation loss and near‐irreversible changes in soil properties. The objective of the study was to determine whet...