Atmospheric nitrogen input to the Kattegat

Asman, W. A. H.; Hertel, Ole; Berkowicz, Ruwim; Christensen, J. H.; Runge, E.; Sørensen, Lise Lotte; Granby, Kit; Nielsen, Helle Lykke; Jensen, Bente Thoft; Gryning, Sven‐Erik; Sempreviva, Anne Maria; Larsen, Søren Ejling; Hummelshøj, P.; Jensen, N.O.; Allerup, Peter; Jørgensen, J. O.; Madsen, Henning; Overgaard, Søren; Vejen, Flemming

doi:10.1080/00785326.1995.10431495

Cited by 31 publications

(8 citation statements)

References 18 publications

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“…Coastal waters, which make up only 15% of the world ocean surface area, account for up to one‐half of the “new” global marine primary productivity (Mackenzie et al, 1991). This new productivity has been attributed in part to the increase in anthropogenic N inputs to coastal waters (Ryther and Dunstan, 1971; Nixon, 1986; Asman et al, 1993; Paerl, 1995). Atmospherically deposited nitrogen is a historically overlooked, yet potentially quite important source of N to coastal waters (Valigura et al, 1996).…”

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confidence: 99%

Spatiotemporal Variability of Wet Atmospheric Nitrogen Deposition to the Neuse River Estuary, North Carolina

Whitall

Paerl

2001

J of Env Quality

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Excessive nitrogen (N) loading to N-sensitive waters such as the Neuse River estuary (North Carolina) has been shown to promote changes in microbial and algal community composition and function (harmful algal blooms), hypoxia and anoxia, and fish kills. Previous studies have estimated that wet atmospheric deposition of nitrogen (WAD-N), as deposition of dissolved inorganic nitrogen (DIN: NO3-, NH3/NH4+) and dissolved organic nitrogen, may contribute at least 15% of the total externally supplied or "new" N flux to the coastal waters of North Carolina. In a 3-yr study from June 1996 to June 1999, we calculated the weekly wet deposition of inorganic and organic N at eleven sites on a northwest-southeast transect in the watershed. The annual mean total (wet DIN + wet organics) WAD-N flux for the Neuse River watershed was calculated to be 956 mg N/m2/yr (15026 Mg N/yr). Seasonally, the spring (March-May) and summer (June-August) months contain the highest total weekly N deposition; this pattern appears to be driven by N concentration in precipitation. There is also spatial variability in WAD-N deposition; in general, the upper portion of the watershed receives the lowest annual deposition and the middle portion of the watershed receives the highest deposition. Based on a range of watershed N retention and in-stream riverine processing values, we estimate that this flux contributes approximately 24% of the total "new" N flux to the estuary.

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confidence: 99%

Spatiotemporal Variability of Wet Atmospheric Nitrogen Deposition to the Neuse River Estuary, North Carolina

Whitall

Paerl

2001

J of Env Quality

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“…Chem. Phys., 3, 2083-2099, 2003 1984Observed 730 HELCOM (1988 1983-1985 Observed 80 872 952 Iversen et al (1989) 1985 Modelled 619 Lindfors et al (1991) 1980-1986 Observed 149 850 999 Heidam (1993) 1988 Modelled 687 Iversen et al (1990) 1988 Modelled 660 Iversen et al (1990) 1989 Modelled 601 Heidam (1993) 1989 Modelled 629 Asman et al (1995) The current model does not take into account seasonal variation in land cover, and furthermore land use is only stratified on sea and land surfaces, where the latter is assumed covered by grass. A detailed land use database is in the process of being implemented together with surface resistances for various land use types combined with information for the entire model domain (the EMEP area) about growing seasons, type of crops etc.…”

Section: Discussion Of Model Performancementioning

confidence: 99%

Operational mapping of atmospheric nitrogen deposition to the Baltic Sea

Hertel¹,

Skjøth²,

Brandt³

et al. 2003

Preprint

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Abstract. A new model system for mapping and forecasting nitrogen deposition to the Baltic Sea has been developed. The system is based on the Lagrangian variable scale transport-chemistry model ACDEP (Atmospheric Chemistry and Deposition model), and aims at delivering deposition estimates to be used as input to marine ecosystem models. The system is tested by comparison of model results to measurements from monitoring stations around the Baltic Sea. The comparison shows that observed annual mean ambient air concentrations and wet depositions are well reproduced by the model. Diurnal mean concentrations of NHx (sum of NH3 and NH4) and NO2 are fairly well reproduced, whereas concentrations of total nitrate (sum of HNO3 and NO3−) are somewhat overestimated by the model. Wet depositions of nitrate and ammonia are fairly well described for annual mean values, whereas the discrepancy is high for the monthly mean values and the wet depositions are rather poorly described concerning the diurnal mean values. The model calculations show that the atmospheric nitrogen deposition has a pronounced south – north gradient with depositions in the range about 1.0 tonnes N km−2 in south and 0.2 tonnes N km−2 in north. The model results show that in 2000 the maximum deposition to the Danish waters appeared during the summer in the algae growth season. For the northern parts of the Baltic the highest depositions were distributed over most of the year.

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“…The average deposition is rather constant whereas the extreme values are highly variable and an order of 20 to 40 times larger than the average values. The ACDEP model results (Table 2) indicate some variation in the average and maximum wet deposition values over the Kattegat Strait (also found by Asman et al, 1995) but the spatial distribution on extreme events cannot be inferred from the present dataset covering only one year.…”

Section: Wet Depositionmentioning

confidence: 96%

On extreme atmospheric and marine nitrogen fluxes and chlorophyll-a levels in the Kattegat Strait

Hasager¹,

Carstensen²,

Ellermann³

et al. 2003

Atmos. Chem. Phys.

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Abstract.A retrospective analysis is carried out to investigate the importance of the vertical fluxes of nitrogen to the marine sea surface layer in which high chlorophyll a levels may cause blooms of harmful algae and subsequent turn over and oxygen depletion at the bottom of the sea. Typically nitrogen is the limiting factor for phytoplankton in the Kattegat Strait during summer periods (May to August) and the major nitrogen inputs come from the atmosphere and deepwater entrainment. The extreme reoccurrence values of nitrogen from atmospheric wet and dry deposition and deep-water flux entrainments are calculated by the periodic maximum method and the results are successfully compared to a map of chlorophyll return periods based on in-situ observations. The one-year return of extreme atmospheric wet deposition is around 60 mg N m −2 day −1 and 30 mg N m −2 day −1 for deep-water entrainment. Atmospheric nitrogen dry deposition is insignificant in the context of algal blooms. At longer time-scales e.g. at 10-year return, the nitrogen deep-water entrainment is larger than the extreme of atmospheric wet deposition. This indicates that the pool of nitrogen released from the sea bottom by deep-water entrainment forced by high winds greatly exceeds the atmospheric pool of nitrogen washed out by precipitation. At the frontal zone of the Kattegat Strait and Skagerrak, the nitrogen deep-water entrainment is very high and this explains the high 10-year return chlorophyll level at 8 mg m −3 in the Kattegat Strait. In the southern part, the extreme chlorophyll level is only 4 mg m −3 according to the statistics of a multi-year time-series of water samples. The chlorophyll level varies greatly in time and space as documented by a series of SeaWiFS satellite maps (OC4v4 algorithm) of chlorophyll ScanFish and buoy observations from an experimental period in the Kattegat Strait. It is recommended to sample in-situ chlorophyll observationCorrespondence to: C. B. Hasager (charlotte.hasager@risoe.dk) collocated in time to the satellite overpasses of e.g. SeaWiFS and ENVISAT MERIS to ensure improved mapping of the chlorophyll levels in the Danish waters.

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Atmospheric nitrogen input to the Kattegat

Cited by 31 publications

References 18 publications

Spatiotemporal Variability of Wet Atmospheric Nitrogen Deposition to the Neuse River Estuary, North Carolina

Spatiotemporal Variability of Wet Atmospheric Nitrogen Deposition to the Neuse River Estuary, North Carolina

Operational mapping of atmospheric nitrogen deposition to the Baltic Sea

On extreme atmospheric and marine nitrogen fluxes and chlorophyll-a levels in the Kattegat Strait

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