Increased Above- and Belowground Plant Input Can Both Trigger Microbial Nitrogen Mining in Subarctic Tundra Soils

Hicks, Lettice C.; Yuan, Mingyue; Brangarí, Albert C.; Rousk, Kathrin; Rousk, Johannes

doi:10.1007/s10021-021-00642-8

Cited by 15 publications

(10 citation statements)

References 67 publications

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“…The NP3 and NP5 treatments were designed to test the indirect fertilizing effect of global warming through N/P addition on vegetation, assuming they mimicked the greater soil mineralization of N and P expected under a warming environment. In comparison, as mentioned before, in wet/acid tundra, an increase in mean temperature of 3 • C would be equivalent to an addition of 7 g N m −2 [18,61]. In addition, in boreal Sphagnum-dominated peatlands (another nutrient poor ecosystem), the effect of an annual N enrichment of about 4 g N m −2 y −1 on Sphagnum productivity was equivalent to the one of a temperature increase of 1 • C [62].…”

Section: Experimental Design and Fertilizationmentioning

confidence: 76%

N/P Addition Is More Likely Than N Addition Alone to Promote a Transition from Moss-Dominated to Graminoid-Dominated Tundra in the High-Arctic

et al. 2022

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Nutrient availability for tundra vegetation could change drastically due to increasing temperatures and frequency of nitrogen deposition in the Arctic. Few studies have simultaneously examined the response of plant communities to these two pressures over a long period. This study aims to assess which driver between increasing nitrogen (N) and phosphorus (P) availability through global warming and increasing N availability alone via N deposition is more likely to transform arctic wetland vegetation and whether there is a time lag in this response. An annual fertilization experiment simulating these nutrient inputs was conducted for 17 years in the Canadian High-Arctic to assess the impact on aboveground net primary productivity, floristic composition, and plant nutrient concentration. While the primary productivity of mosses remains unchanged by fertilization after 17 years, productivity of graminoids was increased slightly by N addition (36% increase at the highest dose). In contrast, the primary productivity of graminoids increased strongly with N/P addition (over 227% increase). We noted no difference in graminoid productivity between the 2nd and 5th year of the experiment, but we observed a 203% increase between the 5th and 17th year in the N/P addition treatments. We also noted a 49% decrease in the total moss cover and an 155% increase in the total graminoid cover between the 2nd and 17th year of N/P addition. These results indicate that the impact of warming through increased N/P availability was greater than those of N deposition alone (N addition) and promoted the transition from a moss-dominated tundra to a graminoid-dominated tundra. However, this transition was subject to a time lag of up to 17 years, suggesting that increased productivity of graminoids resulted from a release of nutrients via the decomposition of lower parts of the moss mat.

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Section: Experimental Design and Fertilizationmentioning

confidence: 76%

N/P Addition Is More Likely Than N Addition Alone to Promote a Transition from Moss-Dominated to Graminoid-Dominated Tundra in the High-Arctic

et al. 2022

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“…However, changes are highly contingent upon site-specific factors, including moisture availability, substrate quality and decomposer community 14,23,24,[26][27][28][29]39,46,47 . Although we focus on short-term decomposition processes, greater early-stage decomposition could accelerate biogeochemical cycling 48 and stimulate the loss of older organic carbon 15,49 through nitrogen mining [50][51][52] or priming of microbial communities 22,53,54 .…”

Section: Discussionmentioning

confidence: 99%

“…With warming, higher temperatures dry surface soils and reduce decomposer activity 57 , as has been observed in warming experiments 16,58 and long-term monitoring 59 . Biotic changes to either plant 14,26,28 or decomposer communities 51,60,61 may also respond in complex ways to environmental change.…”

Section: Discussionmentioning

confidence: 99%

Litter quality outweighs climate as a driver of decomposition across the tundra biome

Thomas¹,

Myers‐Smith²,

Høye³

et al. 2023

Preprint

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Considerable uncertainty exists regarding the strength, direction and relative importance of the drivers of decomposition in the tundra biome, partly due to a lack of coordinated decomposition field studies in this remote environment. Here, we analysed 3717 incubations of two uniform litter types, green and rooibos tea, buried at 330 circum-Arctic and alpine sites to quantify the effects of temperature, moisture and litter quality on decomposition. We found a surprisingly linear positive relationship between decomposition and soil temperature across all sites, counter to theory and previous model estimates. Litter mass loss was greater at wetter sites, even where soils reached almost full water saturation. However, litter quality was the strongest driver of litter mass loss across the tundra biome, explaining six times more variation in summer decomposition than soil temperature. Our results indicate that climate warming will directly increase decomposition across tundra environments. However, the indirect effects of climate change on vegetation communities, and thus plant litter inputs and quality, could have a more profound impact than direct effects on the balance of this globally important carbon store.

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“…To do so, we used soils from a field-experiment in a subarctic tundra heath, where changes in resource availability due to climate change were simulated using birch litter and inorganic N additions, with litter and/or inorganic N supplied either as chronic, annual, additions (to simulate the consequence of gradual warming), or as one large addition during a single growth season (to simulate the consequence of an extreme weather event, e.g. summer heatwave; Hicks et al, 2021). To these soils, a factorial set of C (as glucose), N (as NH 4 NO 3 ) and P (as KH 2 PO 4 / K 2 HPO 4 ) additions were supplied in the laboratory ("limiting factor assays," LFA), to identify the limiting factor for microbial growth, fungal-to-bacterial balance, and decomposition (respiration).…”

Section: Introductionmentioning

confidence: 99%

Limiting resources for soil microbial growth in climate change simulation treatments in the subarctic

Yuan,

Na,

Hicks

et al. 2023

Ecology

Self Cite

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The microbial use of resources to sustain life and reproduce influences for example, decomposition and plant nutrient provisioning. The study of “limiting factors” has shed light on the interaction between plants and their environment. Here, we investigated whether carbon (C), nitrogen (N), or phosphorus (P) was limiting for soil microorganisms in a subarctic tundra heath, and how changes in resource availability associated with climate change affected this. We studied samples in which changes in resource availability due to climate warming were simulated by the addition of birch litter and/or inorganic N. To these soils, we supplied factorial C (as glucose), N (as NH4NO3), and P (as KH2PO4/K2HPO4) additions (“limiting factor assays,” LFA), to determine the limiting factors. The combination of C and P induced large growth responses in all soils and, combined with a systematic tendency for growth increases by C, this suggested that total microbial growth was primarily limited by C and secondarily by P. The C limitation was alleviated by the field litter treatment and strengthened by N fertilization. The microbial growth response to the LFA‐C and LFA‐P addition was strongest in the field‐treatment that combined litter and N addition. We also found that bacteria were closer to P limitation than fungi. Our results suggest that, under a climate change scenario, increased C availability resulting from Arctic greening, treeline advance, and shrubification will reduce the microbial C limitation, while increased N availability resulting from warming will intensify the microbial C limitation. Our results also suggest that the synchronous increase of both C and N availability might lead to a progressive P limitation of microbial growth, primarily driven by bacteria being closer to P limitation. These shifts in microbial resource limitation might lead to a microbial targeting of the limiting element from organic matter, and also trigger competition for nutrients between plants and microorganisms, thus modulating the productivity of the ecosystem.

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Increased Above- and Belowground Plant Input Can Both Trigger Microbial Nitrogen Mining in Subarctic Tundra Soils

Cited by 15 publications

References 67 publications

N/P Addition Is More Likely Than N Addition Alone to Promote a Transition from Moss-Dominated to Graminoid-Dominated Tundra in the High-Arctic

N/P Addition Is More Likely Than N Addition Alone to Promote a Transition from Moss-Dominated to Graminoid-Dominated Tundra in the High-Arctic

Litter quality outweighs climate as a driver of decomposition across the tundra biome

Limiting resources for soil microbial growth in climate change simulation treatments in the subarctic

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