Atmospheric nitrogen inputs into the North Sea: effect on productivity

Abstract. Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ) modeling system and are compared to European Monitoring and Evaluation Programme (EMEP) measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 +  NH4+ and HNO3 +  NO3− and a decrease in NO3− concentrations. However, the overall effect on NH3 +  NH4+ and HNO3 +  NO3− concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is underestimated by the model at most stations. In coastal regions, the total nitrogen deposition (wet and dry) is considerably affected by sea salt particles. Approximately 3–7 % of atmospheric nitrogen deposition into the North Sea is caused by sea salt particles. The contribution is lower in the Baltic Sea region. The stations in the EMEP network provide a solid basis for model evaluation and validation. However, for a more detailed analysis of the impact of sea salt particles on atmospheric nitrogen species, size-resolved measurements of Na+, NH4+, and NO3− are needed.

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Assessment of the atmospheric nitrogen and sulphur inputs into the North Sea using a Lagrangian model

Physics and Chemistry of the Earth Parts A/B/C ◽

10.1016/s1474-7065(02)00153-5 ◽

2002 ◽

Vol 27 (35) ◽

pp. 1507-1515 ◽

Cited By ~ 43

Author(s):

O. Hertel ◽

C. Ambelas Skjøth ◽

L.M. Frohn ◽

E. Vignati ◽

J. Frydendall ◽

...

Keyword(s):

North Sea ◽

Lagrangian Model ◽

Atmospheric Nitrogen ◽

The North ◽

The North Sea

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High atmospheric nitrogen deposition events over the North Sea

Marine Pollution Bulletin ◽

10.1016/0025-326x(93)90554-w ◽

1993 ◽

Vol 26 (12) ◽

pp. 698-703 ◽

Cited By ~ 28

Author(s):

L. Spokes ◽

T. Jickells ◽

A. Rendell ◽

M. Schulz ◽

A. Rebers ◽

...

Keyword(s):

Nitrogen Deposition ◽

North Sea ◽

Atmospheric Nitrogen Deposition ◽

Atmospheric Nitrogen ◽

The North ◽

The North Sea

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Evaluation of atmospheric nitrogen inputs into marine ecosystems of the North Sea and Baltic Sea – part B: contribution by shipping and agricultural emissions

10.5194/bg-2018-365 ◽

2018 ◽

Author(s):

Daniel Neumann ◽

Hagen Radtke ◽

Matthias Karl ◽

Thomas Neumann

Keyword(s):

Baltic Sea ◽

Nitrogen Deposition ◽

Chlorophyll A ◽

North Sea ◽

Atmospheric Nitrogen Deposition ◽

Atmospheric Nitrogen ◽

The Baltic Sea ◽

The North ◽

The North Sea ◽

The Baltic

Abstract. Atmospheric nitrogen deposition constitutes 20 % to 40 % of the nitrogen input into the North Sea and the Baltic Sea contributing to phytoplankton growth and inducing eutrophication. Major contributors to the atmospheric nitrogen emissions in the vicinity of marine water bodies are shipping and agricultural activities. The contribution of individual emission sectors to the biogeochemical nitrogen cycle needs to be evaluated in order to assess improvement of marine water quality through emission reductions of these sectors. Hence, one focus of this modeling study was to evaluate the contribution of total, shipping-related, and agricultural-related nitrogen deposition to dissolved inorganic nitrogen (DIN), particulate organic nitrogen (PON), chlorophyll-a. A second focus of this study was to compare both water bodies with respect to the accumulation and processing of nitrogen from the mentioned sources. These two research questions were evaluated by a modeling study with the coupled physical-biogeochemical model HBM-ERGOM. The fate of atmospheric deposition in total and of atmospheric nitrogen deposition from two individual sources – shipping and agricultural activities – was traced in the marine ecosystem by a tagging method. In the Baltic Sea it was found that the atmospheric nitrogen deposition contributes up to 50 % to the DIN pool at individual locations during summer. On annual average, 13 % are contributed. Approximately 5 % of DIN originated from agricultural activities and 2 % from the shipping sector. In the western and central Baltic Sea, the shipping sector contributed nearly 5 %. The pattern was similar for the agricultural share indicating that these two sources have a higher relevance in these regions. In the Baltic Sea, the atmospheric nitrogen shares of chlorophyll-a and bioavailable PON were 19 % and 18 %, respectively, and, hence, higher than of DIN. In contrast in offshore regions only, atmospheric nitrogen shares to DIN, PON, and chlorophyll-a were on a similar level compared to each other (20 % to 35 %). This difference is caused by high DIN loads and phosphorus limitation in coastal regions of the Baltic Sea. In the North Sea, the atmospheric contribution to DIN was on a similar level but showed considerable spatial variability caused by a north-south gradient. The shipping contribution to DIN was slightly lower (approximately 1.4 %) and the agricultural contribution higher (6 %) compared to the Baltic Sea. The atmospheric contribution to chlorophyll-a and bioavailable PON was considerably lower than in the Baltic Sea and on the level of the atmospheric DIN shares, which is a result of short residence times of nutrients in the North Sea compared to the Baltic Sea. The shipping and agricultural contributions to PON and chlorophyll-a were also lower.

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