scholarly journals Isotope ratios and concentration of N in needles, roots and soils of Norway spruce (Picea abies [L.] Karst.) stands as influenced by atmospheric deposition of N

2012 ◽  
Vol 51 (No. 10) ◽  
pp. 468-475 ◽  
Author(s):  
S. P Sah
Keyword(s):  
Picea Abies ◽  
Atmospheric Deposition ◽  
Norway Spruce ◽  
Isotope Ratios ◽  
Vertical Gradient ◽  
N Deposition ◽  
Climatic Conditions ◽  
Polluted Site ◽  
Atmospheric N Deposition ◽  
N Enrichment

This study aims to investigate the changes in isotope ratios in foliage and soils of two Norway spruce&nbsp;(Picea abies [L.] Karst.) forests greatly differing in their atmospheric N deposition and climatic conditions. As expected, both N concentrations and &delta;<sup>15</sup>N values in needles and roots were found to be significantly higher in the Solling stand (N-saturated) compared to the Hyytial&auml; stand (N-poor). For both stands a typical vertical gradient of the soil <sup>15</sup>N-enrichment was observed. As expected, the soil of N-polluted site (Solling) was <sup>15</sup>N-enriched significantly more than that of N-limited site (Hyytial&auml;) and this is explained by the presence of marked NO<sub>3</sub><sup>&ndash;</sup> leaching at the Solling site. Although the annual trends (1990&ndash;1994) of N concentration in the foliage of spruce trees remained almost constant, their &delta;<sup>15</sup>N values significantly decreased with the increasing years of sampling. The <sup>15</sup>N-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.

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

2011 ◽  
Vol 51 (No. 9) ◽  
pp. 416-422 ◽  
Author(s):  
S.P. Sah
Keyword(s):  
Mineral Soil ◽  
Vertical Gradient ◽  
N Deposition ◽  
Climatic Conditions ◽  
Organic Layer ◽  
Atmospheric N Deposition ◽  
Spruce Forests ◽  
Humus Layer ◽  
N Enrichment ◽  
Deposition Conditions

This study aims to investigate the changes in isotope ratios in foliage and soils of the two spruce forests [Picea abies (L.) Karst.] differing greatly in their atmospheric N deposition and climatic conditions. As expected, both N concentrations and <sup>15</sup>N values in both needles and litter were found to be significantly higher in the Solling stand (N-saturated) compared to the Hyytial&auml; stand (N-poor). For the N-limited site (Hyytial&auml; plot), a typical vertical gradient of the soil <sup>15</sup>N-enrichment (both in organic and mineral soil) was observed. The N-saturated site (Solling) differs from the N-limited site (Hyytial&auml;) with respect to the <sup>15</sup>N abundance trend in organic layer. In the upper organic layer up to O-f horizon, i.e. mor layer (0&ndash;3.5 cm depth) of Solling plot, there is almost a trend of slight soil <sup>15</sup>N-depletion with increasing depth, and then there is a <sup>15</sup>N-enrichment from O-h horizon (humus layer) of organic layer to mineral soil horizons. This is explained by the presence of prominent NO<sub>3</sub><sup>&ndash;</sup> leaching at this plot

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

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.

scholarly journals Atmospheric deposition of nutrients and excess N formation in the North Atlantic

2010 ◽  
Vol 7 (2) ◽  
pp. 777-793 ◽  
Author(s):  
L. M. Zamora ◽  
A. Landolfi ◽  
A. Oschlies ◽  
D. A. Hansell ◽  
H. Dietze ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
North Atlantic ◽  
N2 Fixation ◽  
Transport Model ◽  
N Deposition ◽  
Atmospheric N Deposition ◽  
N Accumulation ◽  
The North ◽  
The North Atlantic ◽  
Main Thermocline

Abstract. Anthropogenic emissions of nitrogen (N) to the atmosphere have been strongly increasing during the last century, leading to greater atmospheric N deposition to the oceans. The North Atlantic subtropical gyre (NASTG) is particularly impacted. Here, upwind sources of anthropogenic N from North American and European sources have raised atmospheric N deposition to rates comparable with N2 fixation in the gyre. However, the biogeochemical fate of the deposited N is unclear because there is no detectable accumulation in the surface waters. Most likely, deposited N accumulates in the main thermocline instead, where there is a globally unique pool of N in excess of the canonical Redfield ratio of 16N:1 phosphorus (P). To investigate this depth zone as a sink for atmospheric N, we used a biogeochemical ocean transport model and year 2000 nutrient deposition data. We examined the maximum effects of three mechanisms that may transport excess N from the ocean surface to the main thermocline: physical transport, preferential P remineralization of sinking particles, and nutrient uptake and export by phytoplankton at higher than Redfield N:P ratios. Our results indicate that atmospheric deposition may contribute 13–19% of the annual excess N input to the main thermocline. Modeled nutrient distributions in the NASTG were comparable to observations only when non-Redfield dynamics were invoked. Preferential P remineralization could not produce realistic results on its own; if it is an important contributor to ocean biogeochemistry, it must co-occur with N2 fixation. The results suggest that: 1) the main thermocline is an important sink for anthropogenic N deposition, 2) non-Redfield surface dynamics determine the biogeochemical fate of atmospherically deposited nutrients, and 3) atmospheric N accumulation in the main thermocline has long term impacts on surface ocean biology.

scholarly journals Low Water Availability Increases Necrosis in Picea abies after Artificial Inoculation with Fungal Root Rot Pathogens Heterobasidion parviporum and Heterobasidion annosum

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 55 ◽  
Author(s):  
Eeva Terhonen ◽  
Gitta Langer ◽  
Johanna Bußkamp ◽  
David Rӑscuţoi ◽  
Kathrin Blumenstein
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Water Availability ◽  
High Water ◽  
Climatic Conditions ◽  
Heterobasidion Annosum ◽  
Economic Losses ◽  
Negative Effects ◽  
Water Group ◽  
Horizontal Length

Research Highlights: Dedicated experiments to investigate how disturbances will affect Heterobasidion sp.—Norway spruce pathosystems are important, in order to develop different strategies to limit the spread of Heterobasidion annosum s.l. under the predicted climate change. Here, we report on a greenhouse experiment to evaluate the effects of water availability on the infection severity of Heterobasidion parviporum or Heterobasidion annosum, respectively, on Picea abies saplings. Background and Objectives: Changes in climatic conditions and intense logging will continue to promote H. annosum s.l. in conifer forests, increasing annual economic losses. Thus, our aim was to test if disease severity in Norway spruce was greater after infection with H. parviporum or H. annosum in low water availability conditions, compared to seedlings with high water availability. Materials and Methods: We performed inoculation studies of three-year-old saplings in a greenhouse. Saplings were treated as high (+) or low (−) water groups: High water group received double the water amount than the low water group. The necrosis observed after pathogen inoculation was measured and analyzed. Results: The seedling growth was negatively influenced in the lower water group. In addition, the water availability enhanced the necrosis length of H. parviporum in phloem and sapwood (vertical length) in the low water group. H. annosum benefited only in horizontal length in the phloem. Conclusions: Disturbances related to water availability, especially low water conditions, can have negative effects on the tree host and benefit the infection ability of the pathogens in the host.

scholarly journals Fate of ammonium 15N in a Norway spruce forest under long-term reduction in atmospheric N deposition

2010 ◽  
Vol 107 (1-3) ◽  
pp. 409-422 ◽  
Author(s):  
Nicole Dörr ◽  
Klaus Kaiser ◽  
Leopold Sauheitl ◽  
Norbert Lamersdorf ◽  
C. Florian Stange ◽  
...  
Keyword(s):  
Norway Spruce ◽  
N Deposition ◽  
Spruce Forest ◽  
Atmospheric N Deposition ◽  
Norway Spruce Forest

Resilience of Norway spruce (Picea abies (L.) Karst) growth to changing climatic conditions in Southwest Germany

2014 ◽  
Vol 315 ◽  
pp. 12-21 ◽  
Author(s):  
Simon Boden ◽  
Hans-Peter Kahle ◽  
Klaus von Wilpert ◽  
Heinrich Spiecker
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Climatic Conditions ◽  
Southwest Germany

scholarly journals Wet and dry deposition of atmospheric nitrogen at ten sites in Northern China

2012 ◽  
Vol 12 (1) ◽  
pp. 753-785 ◽  
Author(s):  
Y. P. Pan ◽  
Y. S. Wang ◽  
G. Q. Tang ◽  
D. Wu
Keyword(s):  
Atmospheric Deposition ◽  
Dry Deposition ◽  
Northern China ◽  
N Deposition ◽  
Ecological Impacts ◽  
Total Flux ◽  
Spatial And Temporal Variation ◽  
Monitoring Networks ◽  
Atmospheric N Deposition ◽  
Total N

Abstract. Emissions of reactive nitrogen (N) species can affect surrounding ecosystems via atmospheric deposition. However, few long-term and multi-site measurements have focused on both the wet and the dry deposition of individual N species in large areas of Northern China. Thus, the magnitude of atmospheric deposition of various N species in Northern China remains uncertain. In this study, the wet and dry atmospheric deposition of different N species was investigated during a three-year observation campaign at ten selected sites in Northern China. The results indicate that N deposition levels in Northern China were high with a ten-site, three-year average of 60.6 kg N ha−1 yr−1. The deposition levels showed spatial and temporal variation in the range of 28.5–100.4 kg N ha−1 yr−1. Of the annual total deposition, 40% was deposited via precipitation, and the remaining 60% was comprised of dry-deposited forms. Compared with gaseous N species, particulate N species were not the major contributor of dry-deposited N; they contributed approximately 10% to the total flux. On an annual basis, oxidized species accounted for 21% of total N deposition, thereby implying that other forms of gaseous N, such as NH3, comprised a dominant portion of the total flux. The contribution of NO3− to N deposition was enhanced in certain urban and industrial areas. As expected, the total N deposition in Northern China was significantly larger than the values reported by national scale monitoring networks in Europe, North America and East Asia because of high rates of wet deposition and gaseous NH3 dry deposition. The results have three important implications. First, atmospheric N deposition in Northern China falls within the range of critical loads for temperate forests and grasslands, a threshold above which harmful ecological effects to specified parts of temperate ecosystems often occur. Second, the magnitude, patterns and forms of N deposition will help to inform simulated N addition experiments, which are used to evaluate ecological impacts on receiving ecosystems. Third, the field-based evidence in this unique deposition dataset validates emission inventories of reactive N species and will help policy-makers control atmospheric pollution. Taken together, these findings show that NH3 emissions should be abated to mitigate high N deposition and associated potential impacts on ecosystems in Northern China.

scholarly journals Atmospheric deposition of nutrients and excess N formation in the North Atlantic

2009 ◽  
Vol 6 (5) ◽  
pp. 9849-9889 ◽  
Author(s):  
L. M. Zamora ◽  
A. Landolfi ◽  
A. Oschlies ◽  
D. Hansell ◽  
H. Dietze ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
North Atlantic ◽  
N2 Fixation ◽  
Transport Model ◽  
N Deposition ◽  
Atmospheric N Deposition ◽  
N Accumulation ◽  
The North ◽  
The North Atlantic ◽  
Main Thermocline

Abstract. Anthropogenic emissions of nitrogen (N) to the atmosphere have been strongly increasing during the last century, leading to greater atmospheric N deposition to the oceans. The North Atlantic subtropical gyre (NASTG) is particularly impacted. Here, upwind sources of anthropogenic N from North American and European sources have raised atmospheric N deposition to rates comparable with N2 fixation in the gyre. However, the biogeochemical fate of the deposited N is unclear because there is no detectable accumulation in the surface waters. Most likely, deposited N accumulates in the main thermocline instead, where there is a globally unique pool of N in excess of the canonical Redfield ratio of 16 N:1 phosphorus (P). To investigate this depth zone as a sink for atmospheric N, we used a biogeochemical ocean transport model and year 2000 nutrient deposition data. We examined the maximum effects of three mechanisms that may transport excess N from the ocean surface to the main thermocline: physical transport, preferential P remineralization of sinking particles, and nutrient uptake and export by phytoplankton at higher than Redfield N:P ratios. Our results indicate that atmospheric deposition may contribute 13–19% of the annual excess N input to the main thermocline. Modeled nutrient distributions in the NASTG were comparable to observations only when non-Redfield dynamics were invoked. Preferential P remineralization could not produce realistic results on its own; if it is an important contributor to ocean biogeochemistry, it must co-occur with N2 fixation. The results suggest that: 1) the main thermocline is an important sink for anthropogenic N deposition, 2) non-Redfield surface dynamics determine the biogeochemical fate of atmospherically deposited nutrients, and 3) atmospheric N accumulation in the main thermocline has long term impacts on surface ocean biology.

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