Western Pacific atmospheric nutrient deposition fluxes, their impact on surface ocean productivity

Martino, Manuela; Hamilton, Douglas S.; Baker, Alex R.; Jickells, Timothy D.; Bromley, T.; Nojiri, Yukihiro; Quack, Birgit; Boyd, Philip W.

doi:10.1002/2013gb004794

Cited by 73 publications

(57 citation statements)

References 95 publications

(230 reference statements)

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“…The model estimates here consider mainly the effects of nitrogen deposition on nitrogen fixation. However, there is increasing evidence that atmospheric iron deposition also plays a key role in nitrogen fixation because of the high iron requirements of nitrogen‐fixing enzymes [ Ito et al ., ; Martino et al ., ; Moore et al ., ; Ward et al ., ]. The dominance of nitrogen fixation we identify here, and the uncertainty in its sensitivity to atmospheric nitrogen and iron inputs and water column phosphorus cycling [ Landolfi et al ., ], suggests that the magnitudes and controls on nitrogen fixation merit further research.…”

Section: Impacts Of Atmospheric Deposition On Water Column Productivitymentioning

confidence: 99%

“…This estimation of an important recycled marine component of DON is consistent with estimates from observational studies on Bermuda [ Altieri et al ., ], although at other locations anthropogenic terrestrial sources have been argued to dominate the DON [ Jickells et al ., ]. The DON model results reported here estimate gross DON deposition at 15–20% of total N deposition (Figure ) which is broadly in line with recent measurements of the proportion of DON in aerosols and rainwater over the Atlantic, 7–10% [ Zamora et al ., ], ~24% [ Lesworth et al ., ], and 19% [ Altieri et al ., ], and Pacific, 16% [ Martino et al ., ]. However, the proportion varies greatly regionally from 4 to 62% [ Zamora et al ., ].…”

Section: Atmospheric Depositionmentioning

confidence: 99%

See 1 more Smart Citation

A reevaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean

Jickells

Buitenhuis

Altieri

et al. 2017

Global Biogeochemical Cycles

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195

169

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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 À1 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.

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Section: Impacts Of Atmospheric Deposition On Water Column Productivitymentioning

confidence: 99%

Section: Atmospheric Depositionmentioning

confidence: 99%

A reevaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean

Jickells

Buitenhuis

Altieri

et al. 2017

Global Biogeochemical Cycles

Self Cite

195

169

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“…S6 also shows the comparison of the annual cycles of the atmospheric concentrations (TP and PO 4 ) and deposition fluxes (dry and wet deposition), against the TM4-ECPL monthly model results. For cruise measurements over the Atlantic and Pacific oceans (Baker et al, 2010;Martino et al, 2014;Powell et al, 2015) and the global compilation of deposition rates (Vet et al, 2014), the observations are also spatially averaged inside the same model grid box. These comparisons show almost similar performance for all sensitivity simulations but with one falling, in most cases, close to the lower edge of observed concentrations and deposition fluxes.…”

Section: Evaluation Of Phosphorus Simulationsmentioning

confidence: 99%

Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modeling study

et al. 2016

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Abstract. The atmospheric cycle of phosphorus (P) is parameterized here in a state-of-the-art global 3-D chemistry transport model, taking into account primary emissions of total P (TP) and soluble P (DP) associated with mineral dust, combustion particles from natural and anthropogenic sources, bioaerosols, sea spray and volcanic aerosols. For the present day, global TP emissions are calculated to be roughly 1.33 Tg-P yr−1, with the mineral sources contributing more than 80 % to these emissions. The P solubilization from mineral dust under acidic atmospheric conditions is also parameterized in the model and is calculated to contribute about one-third (0.14 Tg-P yr−1) of the global DP atmospheric source. To our knowledge, a unique aspect of our global study is the explicit modeling of the evolution of phosphorus speciation in the atmosphere. The simulated present-day global annual DP deposition flux is 0.45 Tg-P yr−1 (about 40 % over oceans), showing a strong spatial and temporal variability. Present-day simulations of atmospheric P aerosol concentrations and deposition fluxes are satisfactory compared with available observations, indicating however an underestimate of about 70 % on current knowledge of the sources that drive the P atmospheric cycle. Sensitivity simulations using preindustrial (year 1850) anthropogenic and biomass burning emission scenarios showed a present-day increase of 75 % in the P solubilization flux from mineral dust, i.e., the rate at which P is converted into soluble forms, compared to preindustrial times, due to increasing atmospheric acidity over the last 150 years. Future reductions in air pollutants due to the implementation of air-quality regulations are expected to decrease the P solubilization flux from mineral dust by about 30 % in the year 2100 compared to the present day. Considering, however, that all the P contained in bioaerosols is readily available for uptake by marine organisms, and also accounting for all other DP sources, a total bioavailable P flux of about 0.17 Tg-P yr−1 to the oceans is derived. Our calculations further show that in some regions more than half of the bioavailable P deposition flux to the ocean can originate from biological particles, while this contribution is found to maximize in summer when atmospheric deposition impact on the marine ecosystem is the highest due to ocean stratification. Thus, according to this global study, a largely unknown but potentially important role of terrestrial bioaerosols as suppliers of bioavailable P to the global ocean is also revealed. Overall, this work provides new insights to the atmospheric P cycle by demonstrating that biological materials are important carriers of bioavailable P, with very important implications for past and future responses of marine ecosystems to global change.

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“…Falkowski et al, 1998;Mills et al, 2004;Jickels et al, 2005 and refs. therein;Martino et al, 2014). In the tropical North Atlantic where phytoplankton communities are nitrogen limited, experiments conducted by Mills et al (2004) have shown Saharan dust addition to stimulate nitrogen fixation in this area, presumably by supplying iron and phosphorous.…”

Section: Influence Of Saharan Dust Depositionmentioning

confidence: 99%

Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust

et al. 2017

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Abstract. Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition, and seasonal patterns were determined in two sediment trap moorings (M4 at 12 • N, 49 • W and M2 at 14 • N, 37 • W) collecting settling particles synchronously from October 2012 to November 2013 at 1200 m of water depth in the open equatorial North Atlantic.The two trap locations showed a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage. Species fluxes were dominated throughout the year by lower photic zone (LPZ) taxa (Florisphaera profunda, Gladiolithus flabellatus) but also included upper photic zone (UPZ) taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.). The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241 × 10 7 ± 76 × 10 7 coccoliths m −2 d −1 at station M4 compared to only 66 × 10 7

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Western Pacific atmospheric nutrient deposition fluxes, their impact on surface ocean productivity

Cited by 73 publications

References 95 publications

A reevaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean

A reevaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean

Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modeling study

Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust

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