scholarly journals Fertilizing riparian forests: nutrient repletion across ecotones with trophic rewilding

2018 ◽  
Vol 373 (1761) ◽  
pp. 20170439 ◽  
Author(s):  
Joseph K. Bump
Keyword(s):  
Climate Warming ◽  
Terrestrial Ecosystems ◽  
N Deposition ◽  
Riparian Forests ◽  
Resource Subsidies ◽  
Atmospheric N Deposition ◽  
Flux Approximation ◽  
Limiting Nutrient ◽  
Moose Population

Trophic rewilding maintains that large mammals are functionally important to resource subsidies and nutrient repletion, yet this prediction is understudied. Here, I report on the potential magnitude and variability of nitrogen that moose populations move from aquatic to terrestrial ecosystems. My aim is to provide justified approximations of the role of moose in the flux of a limiting nutrient across ecotones and to illustrate how this role is linked to wolf predation and climate warming. Using Isle Royale and northeastern Minnesota, USA as contrasting focal systems, I found that the long-term annual N gain for riparian forests likely ranges from 1 to 10 kg N ha –1 yr –1 , depending on the heterogeneity of moose movements. For these systems, this range is equivalent to approximately 4–30% of net annual N mineralization, approximately 62–625% of annual N runoff, approximately 28–333% of annual atmospheric N deposition and approximately 31–312% of the N sequestered by trees. The N flux approximation is most sensitive to moose population levels and, as such, is influenced by wolves, climate warming and disease. The potential for other terrestrial ungulates that feed on aquatic plants to provide significant nutrient repletion across ecotones is unknown but important to examine in the context of trophic rewilding. The extent to which predators influence ungulate abundance indirectly impacts this nutrient repletion. This article is part of the theme issue ‘Trophic rewilding: consequences for ecosystems under global change’.

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.

Impact of diffuse pollution on water quality of the Vltava River (Slapy Reservoir), Czech Republic

1996 ◽  
Vol 33 (4-5) ◽  
pp. 145-152 ◽  
Author(s):  
Ludmila Procházková ◽  
Pavel Blažka ◽  
Jirí Kopácek
Keyword(s):  
Water Quality ◽  
Czech Republic ◽  
Fertilizer Application ◽  
N Deposition ◽  
Point Sources ◽  
Atmospheric N Deposition ◽  
Economic Changes ◽  
Hydrogen Carbonate ◽  
Strong Acids

This study on long-term (36 years) changes of water chemistry in the Vltava River is based on regular monitoring of the Slapy Reservoir, which has a large heterogenous catchment. Ionic concentrations doubled at constant ratio of cations, while the equivalent ratio of anions of strong acids (SO42−, NO3−, Cl−) to hydrogen carbonate increased more than twice between 1959 and 1990. Nitrate levels increased seven times, reflecting mainly rate of fertilization and atmospheric N deposition. Diffuse sources were dominant in N discharge from the basin (at least 60-80%) throughout the period, in extremely dry years the importance of point sources increased. A sharp decline in the fertilizer application since 1990 due to economic changes in the Czech Republic and also decreased emissions of sulphur in Europe has resulted in the slow recovery of water quality.

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

scholarly journals Streamwater responses to reduced nitrogen deposition at four small upland catchments in Norway

AMBIO ◽  
2020 ◽  
Vol 49 (11) ◽  
pp. 1759-1770 ◽  
Author(s):  
Øyvind Kaste ◽  
Kari Austnes ◽  
Heleen A. de Wit
Keyword(s):  
C:N Ratio ◽  
N Deposition ◽  
Major Fraction ◽  
Atmospheric N Deposition ◽  
Total N ◽  
High Precipitation ◽  
Study Sites ◽  
Term Data ◽  
Upland Catchments

Abstract Reduced emissions of nitrogen (N) in Europe have resulted in decreasing atmospheric deposition since 1990. Long-term data (1988–2017) from four small Norwegian catchments located along gradients in N deposition, rainfall, and organic carbon (C) show different responses to 25–30% reductions in N deposition during the same period. At three sites the decreased N deposition caused reduced leaching of nitrate to surface water, whereas the westernmost site showed no decrease, probably due to thin soils with low C:N ratio, poor vegetation cover and high precipitation. The loss of total N to streamwater constituted 30–50% of the N deposition. Losses via denitrification are unknown but assumed to be low, as a major fraction of the catchments are well-drained. Hence, the study sites seem to continue to accumulate N, presumably mostly in soil organic matter. Although atmospheric N deposition has declined, ambient loads might still exceed long-term sustainable levels in these vulnerable ecosystems.

scholarly journals Effects of Climate and Atmospheric Nitrogen Deposition on Early to Mid-Term Stage Litter Decomposition Across Biomes

2021 ◽  
Vol 4 ◽  
Author(s):  
TaeOh Kwon ◽  
Hideaki Shibata ◽  
Sebastian Kepfer-Rojas ◽  
Inger K. Schmidt ◽  
Klaus S. Larsen ◽  
...  
Keyword(s):  
Mass Loss ◽  
Litter Decomposition ◽  
Temporal Dynamics ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
N Deposition ◽  
Atmospheric Nitrogen ◽  
Atmospheric N Deposition ◽  
Rooibos Tea ◽  
Current Mass

Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its temporal dynamics are of significant importance, since their effects might change over the course of the decomposition process. Within the TeaComposition initiative, we incubated Green and Rooibos teas at 524 sites across nine biomes. We assessed how macroclimate and atmospheric inorganic N deposition under current and predicted scenarios (RCP 2.6, RCP 8.5) might affect litter mass loss measured after 3 and 12 months. Our study shows that the early to mid-term mass loss at the global scale was affected predominantly by litter quality (explaining 73% and 62% of the total variance after 3 and 12 months, respectively) followed by climate and N deposition. The effects of climate were not litter-specific and became increasingly significant as decomposition progressed, with MAP explaining 2% and MAT 4% of the variation after 12 months of incubation. The effect of N deposition was litter-specific, and significant only for 12-month decomposition of Rooibos tea at the global scale. However, in the temperate biome where atmospheric N deposition rates are relatively high, the 12-month mass loss of Green and Rooibos teas decreased significantly with increasing N deposition, explaining 9.5% and 1.1% of the variance, respectively. The expected changes in macroclimate and N deposition at the global scale by the end of this century are estimated to increase the 12-month mass loss of easily decomposable litter by 1.1–3.5% and of the more stable substrates by 3.8–10.6%, relative to current mass loss. In contrast, expected changes in atmospheric N deposition will decrease the mid-term mass loss of high-quality litter by 1.4–2.2% and that of low-quality litter by 0.9–1.5% in the temperate biome. Our results suggest that projected increases in N deposition may have the capacity to dampen the climate-driven increases in litter decomposition depending on the biome and decomposition stage of substrate.

scholarly journals A New Approach to Determine the Total Airborne N Input into the Soil/Plant System Using15N Isotope Dilution (ITNI): Results for Agricultural Areas in Central Germany

2001 ◽  
Vol 1 ◽  
pp. 255-260 ◽  
Author(s):  
Rolf W.B. Russow ◽  
Frank Bahme ◽  
Heinz-Ulrich Neue
Keyword(s):  
Isotope Dilution ◽  
Field Experiments ◽  
N Deposition ◽  
Homogeneous Distribution ◽  
Atmospheric N Deposition ◽  
Standard Methods ◽  
Central Germany ◽  
Plant System ◽  
N Input

The atmospheric deposition of nitrogen (N) in the environment is of great concern due to its impact on natural ecosystems including affecting vegetation, reducing biodiversity, increasing tree growth in forests, and the eutrophication of aquatic systems. Taking into account the average annual N emission into the atmosphere in Germany of about 2 million t N (ammonia/ammonium, NOx), and assuming homogeneous distribution throughout Germany, an average N deposition of 45 kg/ha x year can be calculated. Such high atmospheric N deposition could be confirmed by N balances from long-term field experiments in Central Germany (e.g., the Static Fertilization Experiment in Bad Lauchstädt). By contrast, estimates by standard methods indicate a deposition of only about 30 kg N/ha x year. This is because the standard methods are using wet-only or bulk collectors, which fail to take into account gaseous deposition and the direct uptake of atmospheric N by aerial plant parts. Therefore, a new system was developed using15N isotope dilution methodology to measure the actual total atmospheric N input into a soil/plant system (Integrated Total Nitrogen Input, ITNI). A soil/plant system is labeled with [15N]ammonium-[15N]nitrate and the total input of airborne N is calculated from the dilution of this tracer by N from the atmosphere. An average annual deposition of 64 ± 11 kg/ha x year from 1994–2000 was measured with the ITNI system at the Bad Lauchst?dt research farm in the dry belt of Central Germany. Measurements in 1999/2000 at three other sites in Central Germany produced deposition rates of about 60 kg/ha x year. These data clearly show that the total atmospheric N deposition into the soil/plant system determined by the newly developed ITNI system significantly exceeds that obtained from standard wet-only and bulk collectors. The higher atmospheric N depositions found closely match those postulated from the N balances of long-term agricultural field experiments.

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

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.

scholarly journals SOIL MICROBIAL FEEDBACKS TO CLIMATE WARMING AND ATMOSPHERIC N DEPOSITION

2007 ◽  
Vol 31 (2) ◽  
pp. 252-261 ◽  
Author(s):  
ZHANG Nai-Li ◽  
◽  
GUO Ji-Xun ◽  
WANG Xiao-Yu ◽  
MA Ke-Ping
Keyword(s):  
Climate Warming ◽  
N Deposition ◽  
Atmospheric N Deposition ◽  
Soil Microbial

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.

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