GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Atmospheric deposition of nutrients to the North Atlantic Basin (1996)
    Springer
    Biogeochemistry 35 (1996), S. 27-73 
    Details
    ISSN: 1573-515X
    Keywords: dust ; deposition ; iron ; models ; NHx ; NOy ; nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Atmospheric chemical models are used to estimate the deposition rate of various inorganic oxides of nitrogen (NOy), reduced nitrogen species (NHx) and mineral dust to the North Atlantic Ocean (NAO). The estimated deposition of NOy to the NAO (excluding the coastal ocean) and the Caribbean is 360 × 109 Moles-N m−2 yr−1 (5.0 Tg N); this is equivalent to about 13% of the estimated global emission rate (natural and anthropogenic) and a quarter of the emission rate from sources in North America and Europe. In the case of NHx, 258 Moles-N m−2 yr−1 (3.6 Tg N) are deposited to the NAO and the Caribbean; this is about 6% of the global continental emissions. There is relatively little data on the deposition rate of organic nitrogen species; nonetheless, this evidence suggests that concentrations and deposition rates are comparable to those for inorganic nitrogen. Because of anthropogenic emissions, the present-day deposition rate of NOy to the NAO is about five times greater than pre-industrial times largely due to emissions from energy production and biomass burning. The present-day emissions of NHx from continental anthropogenic sources are about four-to-five times greater than natural sources, mostly due to the impact of emissions from animal wastes associated with food production. Indeed, present-day emissions of NHx from animal waste are estimated to be about 10 times greater than the pre-human era. The deposition rate of mineral dust to the NAO is about 170 Tg yr−1; deposited with the dust (assuming average crustal abundances) is about 6 Tg yr−1 of Fe and 0.2 Tg yr−1 of P. Dust deposition in the NAO is almost completely attributable to transport from North African sources; a substantial fraction of the dust over the NAO is probably mobilized as a consequence of land use practices in arid regions and, consequently, it should be regarded as a pollutant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02179824
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Nitrogen and phosphorus budgets of the North Atlantic Ocean and its watershed (1996)
    Springer
    Biogeochemistry 35 (1996), S. 3-25 
    Details
    ISSN: 1573-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Anthropogenic food and energy production extensively mobilize reactive nitrogen (N) in the watershed of the North Atlantic Ocean (NAO). There is wide spread N distribution by both hydrologic and atmospheric processes within the watershed of the NAO, resulting in reactive N accumulation in terrestrial systems. Net denitrification in most estuaries and continental shelves exceeds the amount of N supplied to the shelves by rivers and requires a supply of nitrate from the open ocean. Thus riverine N is only transported to the open ocean in a few areas with the flow from a few major rivers (e.g., Amazon). Atmospheric N deposition to the open ocean has increased and may increase the productivity of the surface ocean. In addition, as a consequence of increased Fe deposition to the open ocean (due in part to anthropogenic processes), the rate of biological N-fixation may have increased resulting in N accumulation in the ocean. Phosphorus (P) is also mobilized by anthropogenic processes (primarily food production). Relative to N, more of the P is transported across the shelf to the open ocean from both estuaries and major rivers. There are several consequences of the increased availability of N and P that are unique to each element. However, the control on primary productivity in both coastal and open ocean ecosystems is dependent on a complex and poorly understood interaction between N and P mobilization and availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02179823
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Estimation of the air/sea exchange of ammonia for the North Atlantic Basin (1996)
    Springer
    Biogeochemistry 35 (1996), S. 275-304 
    Details
    ISSN: 1573-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract As gas phase atmospheric ammonia reacts with acidic aerosol particles it affects the chemical, physical, and optical properties of the particles. A knowledge of the source strengths of NH3 is useful in determining the effect of NH3 on aerosol properties on a regional basis. Here, an attempt is made to determine the direction and magnitude of the air/sea flux of ammonia for the North Atlantic Basin from both measured and modeled seawater and atmospheric ammonia concentrations. Previously reported measured seawater concentrations range from less than 30 to 4600 nM with the highest concentrations reported for the Caribbean Sea, the North Sea, and the Belgium coast. Measured atmospheric ammonia concentrations range from 2 to 500 nmol m−3 with the largest values occurring over the Sargasso Sea, the Caribbean Sea, and the North Sea. For comparison to the measurements, seawater ammonia concentrations were calculated by the Hamburg Model of the Ocean Carbon Cycle (HAMOCC3). HAMOCC3 open ocean values agree well with the limited number of reported measured concentrations. Calculated coastal values are lower than those measured, however, due to the coarse resolution of the model. Atmospheric ammonia concentrations were calculated by the Acid Deposition Model of the Meteorological Synthesizing Center (MSC-W) and by the global 3-dimensional model Moguntia. The two models predict similar annually averaged values but are about an order of magnitude lower than the measured concentrations. Over the North Sea and the NE Atlantic, the direction and magnitude of the air/sea ammonia flux calculated from MSC-W and Moguntia agree within the uncertainty of the calculations. Flux estimates derived from measured data are larger in both the positive and negative direction than the model derived values. The discrepancies between the measured and modeled concentrations and fluxes may be a result of sampling artifacts, inadequate chemistry and transport schemes in the models, or the difficulty in comparing point measurements to time-averaged model values. Sensitivity tests were performed which indicate that, over the range of values expected for the North Atlantic, the accuracy of the calculated flux depends strongly on seawater and atmospheric ammonia concentrations. Clearly, simultaneous and accurate measurements of seawater and atmospheric ammonia concentrations are needed to reduce the uncertainty of the flux calculations, validate the model results, and characterize the role of oceanic ammonia emissions in aerosol processing and nitrogen cycling for the North Atlantic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02179831
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    facet.materialart.
    Unknown
    A reevaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean (2017)
    AGU (American Geophysical Union) | Wiley
    In:  Global Biogeochemical Cycles, 31 (2). pp. 289-305.
    Details
    Publication Date: 2020-02-06
    Description: We report a new synthesis of best estimates of the inputs of fixed nitrogen to the world ocean via atmospheric deposition and compare this to fluvial inputs and dinitrogen fixation. We evaluate the scale of human perturbation of these fluxes. Fluvial inputs dominate inputs to the continental shelf, and we estimate that about 75% of this fluvial nitrogen escapes from the shelf to the open ocean. Biological dinitrogen fixation is the main external source of nitrogen to the open ocean, i.e., beyond the continental shelf. Atmospheric deposition is the primary mechanism by which land-based nitrogen inputs, and hence human perturbations of the nitrogen cycle, reach the open ocean. We estimate that anthropogenic inputs are currently leading to an increase in overall ocean carbon sequestration of ~0.4% (equivalent to an uptake of 0.15 Pg C yr−1 and less than the Duce et al. (2008) estimate). The resulting reduction in climate change forcing from this ocean CO2 uptake is offset to a small extent by an increase in ocean N2O emissions. We identify four important feedbacks in the ocean atmosphere nitrogen system that need to be better quantified to improve our understanding of the perturbation of ocean biogeochemistry by atmospheric nitrogen inputs. These feedbacks are recycling of (1) ammonia and (2) organic nitrogen from the ocean to the atmosphere and back, (3) the suppression of nitrogen fixation by increased nitrogen concentrations in surface waters from atmospheric deposition, and (4) increased loss of nitrogen from the ocean by denitrification due to increased productivity stimulated by atmospheric inputs.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1002/2016GB005586
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
    facet.materialart.
    Unknown
    Atmospheric contribution to excess nitrate development in the subtropical North Atlantic: Atmospheric viewpoint (2008)
    In:  [Talk] In: AGU Fall Meeting 2008, 15.-19.12.2008, San Francisco, USA .
    Details
    Publication Date: 2012-02-23
    Description: Atmospheric deposition of high N:P material to the subtropical North Atlantic has more than doubled in the past century due to anthropogenic activity, and is increasingly thought to be an important source of essential nutrients to the oligotrophic subtropical gyre. However, the long-term fate of North Atlantic atmospheric nitrogen deposition is not well understood. This modeling study evaluated an observed pool of N in excess of Redfield ratios located in the main thermocline as a potential sink for atmospheric N. Modeled atmospheric deposition was added to a coupled ocean ecosystem and circulation model. Results suggest that nearly half of the atmospheric nitrogen entering the North Atlantic is transported to the main thermocline, contributing ~15% of the annual growth of excess N there. Transport mechanisms include differential remineralization of N and P in sinking biogenic particles and physical transport. If atmospheric nutrient inputs from the year 2000 were maintained for 50 years, the model suggests that nutrient deposition would contribute to an increase in excess N of more than 0.4 μM, or an additional 45% of the present signal. Quantifying the fate and important transport mechanisms of deposited atmospheric nutrients will improve our understanding of N cycle dynamics in the North Atlantic, as well as improve N2 fixation estimates based on mass-balance techniques.
    Type: Conference or Workshop Item , NonPeerReviewed
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Talk
  • 6
    facet.materialart.
    Unknown
    Atmospheric contribution to excess nitrate development in the subtropical North Atlantic (2009)
    In:  [Poster] In: Unknown Knowns & Known Unknowns: Chemical Oceanography in a Changing World, Skidaway Institute for Oceanography, 22.-24.02.2009, Savannah, GA, USA .
    Details
    Publication Date: 2012-06-04
    Description: Atmospheric deposition of high N:P material to the subtropical North Atlantic has more than doubled in the past century due to anthropogenic activity, and is increasingly thought to be an important source of essential nutrients to the oligotrophic subtropical gyre. However, the long-term fate of North Atlantic atmospheric nitrogen deposition is not well understood. This modeling study evaluated an observed pool of N in excess of Redfield ratios located in the main thermocline as a potential sink for atmospheric N. Modeled atmospheric deposition was added to a coupled ocean ecosystem and circulation model. Results suggest that nearly half of the atmospheric nitrogen entering the North Atlantic is transported to the main thermocline, contributing ~15% of the annual growth of excess N there. Transport mechanisms include differential remineralization of N and P in sinking biogenic particles and physical transport. If atmospheric nutrient inputs from the year 2000 were maintained for 50 years, the model suggests that nutrient deposition would contribute to an increase in excess N of more than 0.4 μM, or an additional 45% of the present signal. Quantifying the fate and important transport mechanisms of deposited atmospheric nutrients will improve our understanding of N cycle dynamics in the North Atlantic, as well as improve N2 fixation estimates based on mass-balance techniques.
    Type: Conference or Workshop Item , NonPeerReviewed
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Poster
  • 7
    facet.materialart.
    Unknown
    Atmospheric deposition of nutrients and excess N formation in the North Atlantic (2010)
    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 7 . pp. 777-793.
    Details
    Publication Date: 2019-09-23
    Description: 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.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.5194/bg-7-777-2010
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
    facet.materialart.
    Unknown
    Phosphorus stress induced by atmospheric deposition to the surface waters of the subtropical North Atlantic (2011)
    In:  SOLAS News, 13 . pp. 34-36.
    Details
    Publication Date: 2016-09-05
    Type: Article , NonPeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - without review
  • 9
    facet.materialart.
    Unknown
    Impacts of atmospheric anthropogenic nitrogen on the open ocean (2008)
    American Association for the Advancement of Science (AAAS)
    In:  Science, 320 . pp. 893-897.
    Details
    Publication Date: 2016-09-08
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1126/science.1150369
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 10
    facet.materialart.
    Unknown
    A re-evaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean (2017)
    Wiley-Blackwell
    Details
    Publication Date: 2017-01-22
    Description: We report a new synthesis of best estimates of the inputs of fixed nitrogen to the world ocean via atmospheric deposition, and compare this to fluvial inputs and di-nitrogen fixation. We evaluate the scale of human perturbation of these fluxes. Fluvial inputs dominate inputs to the continental shelf, and we estimate about 75% of this fluvial nitrogen escapes from the shelf to the open ocean. Biological di-nitrogen fixation is the main external source of nitrogen to the open ocean, i.e. beyond the continental shelf. Atmospheric deposition is the primary mechanism by which land based nitrogen inputs, and hence human perturbations of the nitrogen cycle, reach the open ocean. We estimate that anthropogenic inputs are currently leading to an increase in overall ocean carbon sequestration of ~0.4% (equivalent to an uptake of 0.15 Pg C yr -1 and less than the Duce et al., 2008 estimate). The resulting reduction in climate change forcing from this ocean CO 2 uptake is offset to a small extent by an increase in ocean N 2 O emissions. We identify four important feedbacks in the ocean atmosphere nitrogen system that need to be better quantified to improve our understanding of the perturbation of ocean biogeochemistry by atmospheric nitrogen inputs. These feedbacks are recycling of (1) ammonia and (2) organic nitrogen from the ocean to the atmosphere and back, (3) the suppression of nitrogen fixation by increased nitrogen concentrations in surface waters from atmospheric deposition, and (4) increased loss of nitrogen from the ocean by denitrification due to increased productivity stimulated by atmospheric inputs.
    Print ISSN: 0886-6236
    Electronic ISSN: 1944-9224
    Topics: Biology , Chemistry and Pharmacology , Geography , Geosciences , Physics
    Published by Wiley-Blackwell on behalf of American Geophysical Union (AGU).
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...