15N natural abundances in two podsol soils of two spruce forests differing in their atmospheric N deposition conditions

This study aims to investigate the changes in isotope ratios in foliage and soils of two Norway spruce (Picea abies [L.] Karst.) forests greatly differing in their atmospheric N deposition and climatic conditions. As expected, both N concentrations and δ15N values in needles and roots were found to be significantly higher in the Solling stand (N-saturated) compared to the Hyytialä stand (N-poor). For both stands a typical vertical gradient of the soil 15N-enrichment was observed. As expected, the soil of N-polluted site (Solling) was 15N-enriched significantly more than that of N-limited site (Hyytialä) and this is explained by the presence of marked NO3– leaching at the Solling site. Although the annual trends (1990–1994) of N concentration in the foliage of spruce trees remained almost constant, their δ15N values significantly decreased with the increasing years of sampling. The 15N-depletion in spruce needle litter from 1990 to 1995 was by 2.0&permil;. This is explained by a slight decrease in N deposition at Solling site during this period.

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Fungi exposed to chronic nitrogen enrichment are less able to decay leaf litter

10.1101/067306 ◽

2016 ◽

Author(s):

Linda T.A. van Diepen ◽

Serita D. Frey ◽

Elizabeth A. Landis ◽

Eric W. Morrison ◽

Anne Pringle

Keyword(s):

Growth Rates ◽

Common Garden ◽

N Deposition ◽

Plant Litter ◽

Atmospheric N Deposition ◽

Saprotrophic Fungi ◽

Soil C ◽

Litter Decay ◽

N Enrichment

AbstractSaprotrophic fungi are the primary decomposers of plant litter in temperate forests, and their activity is critical for carbon (C) and nitrogen (N) cycling. Simulated atmospheric N deposition is associated with reduced fungal biomass, shifts in fungal community structure, slowed litter decay, and soil C accumulation. Although rarely studied, N deposition may also result in novel selective pressures on fungi, affecting evolutionary trajectories. To directly test if long-term N enrichment reshapes fungal behaviors, we isolated decomposer fungi from a longterm (28 year) N addition experiment and used a common garden approach to compare growth rates and decay abilities of isolates from control and N amended plots. Both growth and decay were significantly altered by long-term exposure to N enrichment. Changes in growth rates were idiosyncratic, but litter decay by N isolates was generally lower compared to control isolates of the same species, a response not readily reversed when N isolates were grown in control (low N) environments. Changes in fungal behaviors accompany and perhaps drive previously observed N-induced shifts in fungal diversity, community composition, and litter decay dynamics.

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Controls on ecosystem nitrogen (N) status and carbon (C) balance in red spruce forests located in a region of historically high atmospheric N deposition.

10.33915/etd.8176 ◽

2016 ◽

Author(s):

Kenneth R. Smith

Keyword(s):

N Deposition ◽

Red Spruce ◽

Atmospheric N Deposition ◽

Spruce Forests ◽

C Balance ◽

N Status

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Evaluation of the composite burn index for assessing fire severity in Alaskan black spruce forests

International Journal of Wildland Fire ◽

10.1071/wf08002 ◽

2008 ◽

Vol 17 (4) ◽

pp. 515 ◽

Cited By ~ 109

Author(s):

Eric S. Kasischke ◽

Merritt R. Turetsky ◽

Roger D. Ottmar ◽

Nancy H. F. French ◽

Elizabeth E. Hoy ◽

...

Keyword(s):

Black Spruce ◽

Fire Severity ◽

Strong Predictor ◽

Mineral Soil ◽

Fire Regimes ◽

Quadratic Equation ◽

Organic Layer ◽

Layer Depth ◽

Spruce Forests ◽

Substrate Layer

We evaluated the utility of the composite burn index (CBI) for estimating fire severity in Alaskan black spruce forests by comparing data from 81 plots located in 2004 and 2005 fire events. We collected data to estimate the CBI and quantify crown damage, percent of trees standing after the fire, depth of the organic layer remaining after the fire, depth of burning in the surface organic layer (absolute and relative), and the substrate layer exposed by the fire. To estimate pre-fire organic layer depth, we collected data in 15 unburned stands to develop relationships between total organic layer depth and measures of the adventitious root depth above mineral soil and below the surface of the organic layer. We validated this algorithm using data collected in 17 burned stands where pre-fire organic layer depth had been measured. The average total CBI value in the black spruce stands was 2.46, with most of the variation a result of differences in the CBI observed for the substrate layer. While a quadratic equation using the substrate component of CBI was a relatively strong predictor of mineral soil exposure as a result of fire (R2 = 0.61, P < 0.0001, F = 60.3), low correlations were found between the other measures of fire severity and the CBI (R2 = 0.00–0.37). These results indicate that the CBI approach has limited potential for quantifying fire severity in these ecosystems, in particular organic layer consumption, which is an important factor to understand how ecosystems will respond to changing climate and fire regimes in northern regions.

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Soil Nitrate Mediates the Responses of Plant Community Production to the Frequency of N Addition in a Temperate Grassland: A Decadal Field Experiment

10.21203/rs.3.rs-1106398/v1 ◽

2021 ◽

Author(s):

Changchun Song ◽

Yuqiu Zhang ◽

Zhengru Ren ◽

Haining Lu ◽

Xu Chen ◽

...

Keyword(s):

Plant Community ◽

Net Primary Productivity ◽

Northern China ◽

N Deposition ◽

Temperate Grassland ◽

N Addition ◽

Aboveground Net Primary Productivity ◽

Atmospheric N Deposition ◽

N Enrichment

Abstract PurposeNitrogen (N) enrichment through either artificial N application or atmospheric N deposition often increases ecosystem aboveground net primary productivity (ANPP). Therefore, results from N addition experiments have been used to assess the effects of atmospheric N deposition on ecosystems. However, the frequency of atmospheric N deposition is higher than that of artificial N addition. Whether the frequency of N addition alters the long-term response of ecosystem ANPP remains unclear. MethodsWe conducted a N addition frequency experiment from 2010 in a temperate grassland, northern China. Plant community ANPP was collected in 2019 and 2020, and soil physicochemical properties were measured in 2020. ResultsPlant community ANPP was significantly enhanced by N addition, whereas these increments declined with the frequency of N addition. The responses of the grasses ANPP to the frequency of N addition were similar to those of the plant community ANPP. Forbs ANPP was not significantly altered by the frequency of N addition. Meanwhile, soil ammonium and nitrate (NO3−–N) concentrations decreased with increasing N addition frequency, while the soil water content (SWC) and pH were similar among the frequencies of N addition. Moreover, SWC and soil NO3−–N jointly promoted grasses ANPP, ultimately increasing the plant community ANPP. ConclusionOur findings extend the water and N co-limitation hypothesis by specifying the preference for NO3−–N in arid/semi-arid regions. This study also illustrates that a higher frequency of N addition is more suitable for assessing the long-term impacts of atmospheric N deposition on ecosystems.

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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

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b945160eed9.16985540 ◽

2017 ◽

Author(s):

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.

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Canopy uptake of atmospheric N deposition at a conifer forest: part I -canopy N budget, photosynthetic efficiency and net ecosystem exchange

Tellus B ◽

10.3402/tellusb.v59i3.17018 ◽

2007 ◽

Vol 59 (3) ◽

Cited By ~ 1

Author(s):

H. Sievering ◽

T. Tomaszewski ◽

J. Torizzo

Keyword(s):

Photosynthetic Efficiency ◽

Net Ecosystem Exchange ◽

N Deposition ◽

Conifer Forest ◽

Atmospheric N Deposition ◽

N Budget ◽

Canopy Uptake

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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

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.21610/conferencearticle_58b43155bc901 ◽

2017 ◽

Author(s):

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.

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Characterisation of production of organic rich topsoil from sludge

Water Science & Technology ◽

10.2166/wst.2000.0205 ◽

2000 ◽

Vol 42 (9) ◽

pp. 195-201 ◽

Cited By ~ 1

Author(s):

P. Andreasen ◽

P. B. Mortensen ◽

A. Stubsgaard ◽

B. Langdahl

Keyword(s):

Organic Matter ◽

Oxygen Consumption ◽

Oxygen Transport ◽

Mineral Soil ◽

Climatic Conditions ◽

Growth Media ◽

Soil Mixture ◽

Water Suspension ◽

Aerobic Process ◽

Stable Product

The stabilisation of a sludge-mineral soil mixture and a method to evaluate the state of stabilisation were investigated. The organic matter and nitrogen content are reduced up to 50% during a stabilisation process of three months under Danish climatic conditions. The stabilisation was shown to be an aerobic process limited by oxygen transport within the mixture. The degree of stabilisation was evaluated by oxygen consumption in a water suspension and the results showed that a stable product was achieved when oxygen consumption was stable and in the level of natural occurring aerobic soils (0.1 mgO2/(g DS*hr). The study thereby demonstrates that a stability of a growth media can be controlled by the oxygen consumption method tested.

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Soil acidity in 1970 and 1989 in a coniferous forest in southwest Finland

Canadian Journal of Soil Science ◽

10.4141/s96-099 ◽

1998 ◽

Vol 78 (3) ◽

pp. 477-479 ◽

Cited By ~ 1

Author(s):

C. J. Westman ◽

S. Jauhiainen

Keyword(s):

Key Words ◽

Soil Ph ◽

Soil Acidity ◽

Mineral Soil ◽

Coniferous Forest ◽

Soil Layers ◽

Water Suspension ◽

Ph Values ◽

Humus Layer ◽

Repeated Sampling

Forest soil pH in southwest Finland was measured with identical sampling and analysing methods in 1970 and 1989. The acidity of the organic humus layer increased significantly as pH values measured on water and on salt suspensions decreased between the two sampling dates. For the mineral soil layers, no unambiguous trend was found. pH values measured on salt suspension tended to be unchanged or lower, while pH on water suspension in some soil layers were even higher in 1989 than in 1970. Key words: pH, repeated sampling

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