scholarly journals Subalpine grassland productivity increased with warmer and drier conditions, but not with higher N deposition, in an altitudinal transplantation experiment

2021 ◽  
Vol 18 (6) ◽  
pp. 2075-2090
Author(s):  
Matthias Volk ◽  
Matthias Suter ◽  
Anne-Lena Wahl ◽  
Seraina Bassin
Keyword(s):  
Soil Moisture ◽  
Global Change ◽  
Temperature Change ◽  
Altitudinal Gradient ◽  
Carbon Sink ◽  
Irrigation Treatment ◽  
N Deposition ◽  
Yield Response ◽  
Atmospheric N Deposition ◽  
Common Location

Abstract. Multiple global change drivers affect plant productivity of grasslands and thus ecosystem services like forage production and the soil carbon sink. Subalpine grasslands seem particularly affected and may serve as a proxy for the cold, continental grasslands of the Northern Hemisphere. Here, we conducted a 4-year field experiment (AlpGrass) with 216 turf monoliths, subjected to three global change drivers: warming, moisture, and N deposition. Monoliths from six different subalpine pastures were transplanted to a common location with six climate scenario sites (CSs). CSs were located along an altitudinal gradient from 2360 to 1680 m a.s.l., representing an April–October mean temperature change of −1.4 to +3.0 ∘C, compared to CSreference with no temperature change and with climate conditions comparable to the sites of origin. To uncouple temperature effects along the altitudinal gradient from soil moisture and soil fertility effects, an irrigation treatment (+12 %–21 % of ambient precipitation) and an N-deposition treatment (+3 kg and +15 kg N ha−1 a−1) were applied in a factorial design, the latter simulating a fertilizing air pollution effect. Moderate warming led to increased productivity. Across the 4-year experimental period, the mean annual yield peaked at intermediate CSs (+43 % at +0.7 ∘C and +44 % at +1.8 ∘C), coinciding with ca. 50 % of days with less than 40 % soil moisture during the growing season. The yield increase was smaller at the lowest, warmest CS (+3.0 ∘C) but was still 12 % larger than at CSreference. These yield differences among CSs were well explained by differences in soil moisture and received thermal energy. Irrigation had a significant effect on yield (+16 %–19 %) in dry years, whereas atmospheric N deposition did not result in a significant yield response. We conclude that productivity of semi-natural, highly diverse subalpine grassland will increase in the near future. Despite increasingly limiting soil water content, plant growth will respond positively to up to +1.8 ∘C warming during the growing period, corresponding to +1.3 ∘C annual mean warming.

scholarly journals The rising productivity of alpine grassland under warming, drought and N-deposition treatments

2020 ◽  
Author(s):  
Matthias Volk ◽  
Matthias Suter ◽  
Anne-Lena Wahl ◽  
Seraina Bassin
Keyword(s):  
Temperature Change ◽  
Irrigation Treatment ◽  
Climate Scenario ◽  
Growing Season ◽  
Experimental Period ◽  
N Deposition ◽  
Climate Conditions ◽  
Common Location ◽  
The Mean ◽  
C 50

Abstract. We conducted a four-year warming × moisture × N-deposition field-experiment (AlpGrass) with 216 turf monoliths from six different subalpine pastures (sites of origin). At a common location, the monoliths were replanted at six climate scenario sites (CS) along an altitudinal gradient from 2360 to 1680 m a.s.l., representing an April–October temperature change of −1.4 °C to +3.0 °C, compared to CSreference with no temperature change and with climate conditions comparable to the sites of origin. We further applied an irrigation treatment (+12–21 % of ambient precipitation) and an N-deposition treatment (+3 kg and +15 kg N ha−1 a−1), the latter simulating a fertilizing air pollution effect. Moderate warming led to increased productivity. Across the four-year experimental period, the mean annual yield peaked at intermediate CSs (+43 % at +0.7 °C and +44 % at +1.8 °C), coinciding with c. 50 % of days with dry soil during the growing season (growing-season-days with soil moisture

scholarly journals Consistent Effects of Canopy vs. Understory Nitrogen Addition on Soil Respiration and Net Ecosystem Production in Moso Bamboo Forests

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1427
Author(s):  
Chunju Cai ◽  
Zhihan Yang ◽  
Liang Liu ◽  
Yunsen Lai ◽  
Junjie Lei ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Carbon Cycling ◽  
Forest Canopy ◽  
Carbon Sink ◽  
N Deposition ◽  
Net Ecosystem Production ◽  
Moso Bamboo ◽  
Atmospheric N Deposition ◽  
Ecosystem Carbon ◽  
Ecosystem Production

Nitrogen (N) deposition has been well documented to cause substantial impacts on ecosystem carbon cycling. However, the majority studies of stimulating N deposition by direct N addition to forest floor have neglected some key ecological processes in forest canopy (e.g., N retention and absorption) and might not fully represent realistic atmospheric N deposition and its effects on ecosystem carbon cycling. In this study, we stimulated both canopy and understory N deposition (50 and 100 kg N ha−1 year−1) with a local atmospheric NHx:NOy ratio of 2.08:1, aiming to assess whether canopy and understory N deposition had similar effects on soil respiration (RS) and net ecosystem production (NEP) in Moso bamboo forests. Results showed that RS, soil autotrophic (RA), and heterotrophic respiration (RH) were 2971 ± 597, 1472 ± 579, and 1499 ± 56 g CO2 m−2 year−1 for sites without N deposition (CN0), respectively. Canopy and understory N deposition did not significantly affect RS, RA, and RH, and the effects of canopy and understory N deposition on these soil fluxes were similar. NEP was 1940 ± 826 g CO2 m−2 year−1 for CN0, which was a carbon sink, indicating that Moso bamboo forest the potential to play an important role alleviating global climate change. Meanwhile, the effects of canopy and understory N deposition on NEP were similar. These findings did not support the previous predictions postulating that understory N deposition would overestimate the effects of N deposition on carbon cycling. However, due to the limitation of short duration of N deposition, an increase in the duration of N deposition manipulation is urgent and essential to enhance our understanding of the role of canopy processes in ecosystem carbon fluxes in the future.

Impacts of long-term warming and enhanced nitrogen and sulfur deposition on carbon sink potential in a boreal peatland

2021 ◽  
Author(s):  
Tuula Larmola ◽  
Liisa Maanavilja ◽  
Heikki Kiheri ◽  
Mats Nilsson ◽  
Matthias Peichl
Keyword(s):  
Global Change ◽  
Wet Deposition ◽  
Carbon Sink ◽  
Ecosystem Respiration ◽  
N Deposition ◽  
Ecosystem Responses ◽  
Gross Photosynthesis ◽  
Poor Fen ◽  
The Individual

<p>In order to assess peatland carbon sink potential under multiple global change perturbations, we examined the individual and combined effects of long-term warming and enhanced nitrogen (N) and sulfur (S) deposition on ecosystem CO<sub>2 </sub>exchange at one of the longest-running experiments on peatlands, Degerö Stormyr poor fen, Sweden. The site has been treated with NH<sub>4</sub>NO<sub>3</sub> (15 times ambient annual wet deposition), Na<sub>2</sub>SO<sub>4</sub> (6 times ambient annual wet deposition) and elevated temperature (air +3.6 C) for 23 years. Gross photosynthesis, ecosystem respiration and net CO<sub>2</sub> exchange were measured weekly during June-August using chambers. After 23 years, two of the experimental perturbations: N addition and warming individually reduced net CO<sub>2</sub> uptake potential down to 0.3-0.4 fold compared to the control mainly due to lower gross photosynthesis. Under S only treatment ecosystem CO<sub>2</sub> fluxes were largely unaltered. In contrast, the combination of S and N deposition and warming led to a more pronounced effect and close to zero net CO<sub>2</sub> uptake potential or net C source. Our study emphasizes the value of the long-term multifactor experiments in examining the ecosystem responses: simultaneous perturbations can have nonadditive interactions that cannot be predicted based on individual responses and thus, must be studied in combination when evaluating feedback mechanisms to ecosystem C sink potential under global change.</p>

scholarly journals Responses of Ecosystem CO2Fluxes to Short-Term Experimental Warming and Nitrogen Enrichment in an Alpine Meadow, Northern Tibet Plateau

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ning Zong ◽  
Peili Shi ◽  
Jing Jiang ◽  
Minghua Song ◽  
Dingpeng Xiong ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Global Change ◽  
Alpine Meadow ◽  
N Deposition ◽  
Plant Production ◽  
Tibet Plateau ◽  
N Availability ◽  
Soil N ◽  
N Addition ◽  
Alpine Ecosystems

Over the past decades, the Tibetan Plateau has experienced pronounced warming, yet the extent to which warming will affect alpine ecosystems depends on how warming interacts with other influential global change factors, such as nitrogen (N) deposition. A long-term warming and N manipulation experiment was established to investigate the interactive effects of warming and N deposition on alpine meadow. Open-top chambers were used to simulate warming. N addition, warming, N addition × warming, and a control were set up. In OTCs, daytime air and soil temperature were warmed by 2.0°C and 1.6°C above ambient conditions, but soil moisture was decreased by 4.95 m3 m−3. N addition enhanced ecosystem respiration (Reco); nevertheless, warming significantly decreased Reco. The decline of Reco resulting from warming was cancelled out by N addition in late growing season. Our results suggested that N addition enhanced Reco by increasing soil N availability and plant production, whereas warming decreased Reco through lowering soil moisture, soil N supply potential, and suppression of plant activity. Furthermore, season-specific responses of Reco indicated that warming and N deposition caused by future global change may have complicated influence on carbon cycles in alpine ecosystems.

ATMOSPHERIC N DEPOSITION TO THE COASTAL AREA OF THE BLACK SEA: SOURCES, INTRA-ANNUAL VARIATIONS AND IMPORTANCE FOR BIOGEOCHEMISTRY AND PRODUCTIVITY OF THE SURFACE LAYER

2017 ◽  
Author(s):  
Alla Varenik ◽  
Alla Varenik ◽  
Sergey Konovalov ◽  
Sergey Konovalov
Keyword(s):  
Primary Production ◽  
Black Sea ◽  
Marine Ecosystem ◽  
C:N Ratio ◽  
N Deposition ◽  
Local Source ◽  
The Black Sea ◽  
Coastal Zones ◽  
Atmospheric N Deposition ◽  
Urban Location

Atmospheric precipitations can be an important source of nutrients to open and coastal zones of marine ecosystem. Jickells [1] has published that atmospheric depositions can sup-port 5-25% of nitrogen required to primary production. Bulk atmospheric precipitations have been collected in a rural location at the Black Sea Crimean coast – Katsiveli settlement, and an urban location – Sevastopol city. Samples have been analyzed for inorganic fixed nitrogen (IFN) – nitrate, nitrite, and ammonium. Deposi-tions have been calculated at various space and time scales. The monthly volume weighted mean concentration of IFN increases from summer to winter in both locations. A significant local source of IFN has been revealed for the urban location and this source and its spatial influence have been quantified. IFN deposition with atmospheric precipitations is up to 5% of its background content in the upper 10 m layer of water at the north-western shelf of the Black Sea. Considering Redfield C:N ratio (106:16) and the rate of primary production (PP) in coastal areas of the Black Sea of about 100-130 g C m-2 year-1 we have assessed that average atmospheric IFN depositions may intensify primary production by 4.5% for rural locations, but this value is increased many-fold in urban locations due to local IFN sources.

ATMOSPHERIC N DEPOSITION TO THE COASTAL AREA OF THE BLACK SEA: SOURCES, INTRA-ANNUAL VARIATIONS AND IMPORTANCE FOR BIOGEOCHEMISTRY AND PRODUCTIVITY OF THE SURFACE LAYER

2017 ◽  
Author(s):  
Alla Varenik ◽  
Alla Varenik ◽  
Sergey Konovalov ◽  
Sergey Konovalov
Keyword(s):  
Primary Production ◽  
Black Sea ◽  
Marine Ecosystem ◽  
C:N Ratio ◽  
N Deposition ◽  
Local Source ◽  
The Black Sea ◽  
Coastal Zones ◽  
Atmospheric N Deposition ◽  
Urban Location

Atmospheric precipitations can be an important source of nutrients to open and coastal zones of marine ecosystem. Jickells [1] has published that atmospheric depositions can sup-port 5-25% of nitrogen required to primary production. Bulk atmospheric precipitations have been collected in a rural location at the Black Sea Crimean coast – Katsiveli settlement, and an urban location – Sevastopol city. Samples have been analyzed for inorganic fixed nitrogen (IFN) – nitrate, nitrite, and ammonium. Deposi-tions have been calculated at various space and time scales. The monthly volume weighted mean concentration of IFN increases from summer to winter in both locations. A significant local source of IFN has been revealed for the urban location and this source and its spatial influence have been quantified. IFN deposition with atmospheric precipitations is up to 5% of its background content in the upper 10 m layer of water at the north-western shelf of the Black Sea. Considering Redfield C:N ratio (106:16) and the rate of primary production (PP) in coastal areas of the Black Sea of about 100-130 g C m-2 year-1 we have assessed that average atmospheric IFN depositions may intensify primary production by 4.5% for rural locations, but this value is increased many-fold in urban locations due to local IFN sources.

Indirect N2O emission due to atmospheric N deposition for the Netherlands

2005 ◽  
Vol 39 (32) ◽  
pp. 5827-5838 ◽  
Author(s):  
Hugo Denier van der Gon ◽  
Albert Bleeker
Keyword(s):  
The Netherlands ◽  
N2o Emission ◽  
N Deposition ◽  
Atmospheric N Deposition

scholarly journals Microbial Mechanisms Mediating Increased Soil C Storage under Elevated Atmospheric N Deposition

2012 ◽  
Vol 79 (4) ◽  
pp. 1191-1199 ◽  
Author(s):  
Sarah D. Eisenlord ◽  
Zachary Freedman ◽  
Donald R. Zak ◽  
Kai Xue ◽  
Zhili He ◽  
...  
Keyword(s):  
Forest Floor ◽  
Forest Ecosystems ◽  
N Deposition ◽  
Fungal Communities ◽  
Functional Genes ◽  
Atmospheric N Deposition ◽  
Soil C ◽  
C Storage ◽  
Genes Encoding ◽  
Soil C Storage

ABSTRACTFuture rates of anthropogenic N deposition can slow the cycling and enhance the storage of C in forest ecosystems. In a northern hardwood forest ecosystem, experimental N deposition has decreased the extent of forest floor decay, leading to increased soil C storage. To better understand the microbial mechanisms mediating this response, we examined the functional genes derived from communities of actinobacteria and fungi present in the forest floor using GeoChip 4.0, a high-throughput functional-gene microarray. The compositions of functional genes derived from actinobacterial and fungal communities was significantly altered by experimental nitrogen deposition, with more heterogeneity detected in both groups. Experimental N deposition significantly decreased the richness and diversity of genes involved in the depolymerization of starch (∼12%), hemicellulose (∼16%), cellulose (∼16%), chitin (∼15%), and lignin (∼16%). The decrease in richness occurred across all taxonomic groupings detected by the microarray. The compositions of genes encoding oxidoreductases, which plausibly mediate lignin decay, were responsible for much of the observed dissimilarity between actinobacterial communities under ambient and experimental N deposition. This shift in composition and decrease in richness and diversity of genes encoding enzymes that mediate the decay process has occurred in parallel with a reduction in the extent of decay and accumulation of soil organic matter. Our observations indicate that compositional changes in actinobacterial and fungal communities elicited by experimental N deposition have functional implications for the cycling and storage of carbon in forest ecosystems.

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