scholarly journals Fluxes and sources of nutrients and trace metals atmospheric deposition in the northwestern Mediterranean

2018 ◽  
Author(s):  
Karine Desboeufs ◽  
Elisabeth Bon Nguyen ◽  
Servanne Chevaillier ◽  
Sylvain Triquet ◽  
François Dulac
Keyword(s):  
Trace Metals ◽  
Atmospheric Deposition ◽  
Sampling Period ◽  
N Deposition ◽  
Anthropogenic Sources ◽  
Large Contribution ◽  
Dust Deposition ◽  
Dust Sources ◽  
Dust Events

Abstract. Total atmospheric deposition was collected on a weekly basis over 3.5-yr (March 2008–October 2011) at a remote coastal site on the west coast of Corsica Island. Deposition time series of macro and micro-nutrient (N, P, Si, Fe), and trace metals (As, Cr, Cu, Mn, Ni, V, Zn) are investigated in terms of variability and source apportionment (from fluxes of proxies for aerosol sources (Al, Ti, Ca, Na, Mg, S, Sr, K, Pb)). The highest fluxes are recorded for Si, P, then Fe for nutrients, and for Zn and Mn for trace metals. For the majority of elements, data show some weeks with high episodic fluxes, except for N, Cr and V which present the lowest variability. Twelve intense mineral dust deposition events are identified during the sampling period. The contribution of these events to the fluxes of Fe and Si represents 52 % and 57 % of their total fluxes, respectively, confirming the important role of these sporadic dust events on the inputs of these elements. For N and P, the contribution of these intense dust deposition events is lower and reaches 10 and 15 %, respectively. Out of these most intense events, positive matrix factorization (PMF) was applied to our total deposition database in order to identify the main sources of nutrients and trace metals deposited. Results show that P deposition is mainly associated to anthropogenic biomass burning inputs. For N deposition, inputs associated to marine sources (maybe associated to the reaction of anthropogenic N on NaCl particles) and anthropogenic sources are quasi-similar. A good correlation is obtained between N and S fluxes, supporting a common origin associated to the inorganic secondary aerosol, i.e. ammonium sulfate and ammonium nitrate. For trace metals, their origin is very variable: with a large contribution of natural dust sources for Ni or Mn and on the contrary of anthropogenic sources for V and Zn.

scholarly journals Fluxes and sources of nutrient and trace metal atmospheric deposition in the northwestern Mediterranean

2018 ◽  
Vol 18 (19) ◽  
pp. 14477-14492 ◽  
Author(s):  
Karine Desboeufs ◽  
Elisabeth Bon Nguyen ◽  
Servanne Chevaillier ◽  
Sylvain Triquet ◽  
François Dulac
Keyword(s):  
Trace Metals ◽  
Atmospheric Deposition ◽  
Sampling Period ◽  
N Deposition ◽  
Anthropogenic Sources ◽  
Large Contribution ◽  
Dust Deposition ◽  
Dust Sources ◽  
Dust Events

Abstract. Total atmospheric deposition was collected on a weekly basis over 3.5 years (March 2008–October 2011) at a remote coastal site on the west coast of Corsica. Deposition time series of macro- and micronutrients (N, P, Si, Fe) and trace metals (As, Cr, Cu, Mn, Ni, V, Zn) are investigated in terms of variability and source apportionment (from fluxes of proxies for aerosol sources (Al, Ti, Ca, Na, Mg, S, Sr, K, Pb)). The highest fluxes are recorded for Si, P, and Fe for nutrients and Zn and Mn for trace metals. For the majority of elements, data show some weeks with high episodic fluxes, except for N, Cr, and V, which present the lowest variability. A total of 12 intense mineral dust deposition events are identified during the sampling period. The contribution of these events to the fluxes of Fe and Si represents 52 % and 57 % of their total fluxes, respectively, confirming the important role of these sporadic dust events in the inputs of these elements in the Mediterranean. For N and P, the contribution of these intense dust deposition events is lower and reaches 10 % and 15 %, respectively. Out of these most intense events, positive matrix factorization (PMF) was applied to our total deposition database in order to identify the main sources of nutrients and trace metals deposited. Results show that P deposition is mainly associated with anthropogenic biomass burning inputs. For N deposition, inputs associated with marine sources (maybe associated with the reaction of anthropogenic N on NaCl particles) and anthropogenic sources are quasi-similar. A good correlation is obtained between N and S fluxes, supporting a common origin associated with inorganic secondary aerosol, i.e., ammonium sulfate. For trace metals, their origin is very variable: with a large contribution of natural dust sources for Ni or Mn and conversely of anthropogenic sources for V and Zn.

scholarly journals Quantification of iron-rich volcanogenic dust emissions and deposition over the ocean from Icelandic dust sources

2014 ◽  
Vol 11 (23) ◽  
pp. 6623-6632 ◽  
Author(s):  
O. Arnalds ◽  
H. Olafsson ◽  
P. Dagsson-Waldhauserova
Keyword(s):  
Large Scale ◽  
Dust Emission ◽  
Dust Storms ◽  
Dust Event ◽  
Dust Deposition ◽  
Dust Emissions ◽  
Dust Sources ◽  
Basaltic Composition ◽  
Limiting Nutrient ◽  
Dust Events

Abstract. Iceland has extremely active dust sources that result in large-scale emissions and deposition on land and at sea. The dust has a volcanogenic origin of basaltic composition with about 10% Fe content. We used two independent methods to quantify dust emission from Iceland and dust deposition at sea. Firstly, the aerial extent (map) of deposition on land was extended to ocean areas around Iceland. Secondly, surveys of the number of dust events over the past decades and calculations of emissions and sea deposition for the dust storms were made. The results show that total emissions range from 30.5 (dust-event-based calculation) to 40.1 million t yr−1 (map calculation), which places Iceland among the most active dust sources on Earth. Ocean deposition ranges between 5.5 (dust event calculations) and 13.8 million tons (map calculation). Calculated iron deposition from Icelandic dust ranges between 0.567 and 1.4 million tons, which are distributed over wide areas (>370 000 km2) and consist of fine reactive volcanic materials. The paper provides the first quantitative estimate of total dust emissions and oceanic deposition from Iceland. Iron is a limiting nutrient for primary production in the oceans around Iceland, and the dust is likely to affect Fe levels in Icelandic ocean waters.

Dust and pyrogenic iron boost phytoplankton blooms in sub-Antarctic waters of the Tasman Sea

2020 ◽  
Author(s):  
Joan Llort ◽  
Richard J. Matear ◽  
Pete G. Strutton ◽  
Andrew R. Bowie ◽  
Zanna Chase
Keyword(s):  
Atmospheric Deposition ◽  
Atmospheric Aerosols ◽  
Phytoplankton Bloom ◽  
Early Summer ◽  
Biogeochemical Model ◽  
Dust Deposition ◽  
Bloom Period ◽  
Tasman Sea ◽  
Dust Events ◽  
Upper Mixed Layer

<p>Although it is commonly accepted that atmospheric deposition of Fe particles can fertilise phytoplankton, there is yet no clear evidence on how such a fertilisation effect takes place. Several studies have attempted to link individual dust events with surface chlorophyll responses but generally, they do not find a clear correspondence between dust deposition and its impact on chlorophyll. In this work, we use a biogeochemical model to show that the atmospheric deposition of Fe in high-latitude seas, rather than creating instantaneous phytoplankton responses, replenish the upper mixed layer of the ocean during the pre-bloom period, from winter to early summer. The Fe accumulated at the surface boosts the phytoplankton bloom of the following summer, resulting in surface chlorophyll accumulations of up to 3 times larger than the years without atmospheric deposition. We used this mechanism to explain the strong inter-annual variability of the phytoplankton bloom in sub-Antarctic iron-limited waters east of Australia. Putting together more than a 15-years-long record of ocean colour observations and atmospheric aerosols reanalysis we uncovered a strong correlation (r<sup>2</sup>>0.6) between the dust that crossed the region during the pre-bloom period and the magnitude of the surface chlorophyll bloom. Interestingly, the correlation increased when taking into account pyrogenic aerosols in addition to dust. Our study presents the first observational link between Climate Change-enhanced droughts and wildfires, atmospheric aerosols and primary production of iron-limited waters.</p>

scholarly journals Introduction: Process studies at the air–sea interface after atmospheric deposition in the Mediterranean Sea – objectives and strategy of the PEACETIME oceanographic campaign (May–June 2017)

2020 ◽  
Vol 17 (22) ◽  
pp. 5563-5585
Author(s):  
Cécile Guieu ◽  
Fabrizio D'Ortenzio ◽  
François Dulac ◽  
Vincent Taillandier ◽  
Andrea Doglioli ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Mediterranean Sea ◽  
Anthropogenic Sources ◽  
Dust Deposition ◽  
Action Strategy ◽  
Process Studies ◽  
In Situ Observations ◽  
The Mediterranean ◽  
First Time

Abstract. In spring, the Mediterranean Sea, a well-stratified low-nutrient–low-chlorophyll region, receives atmospheric deposition by both desert dust from the Sahara and airborne particles from anthropogenic sources. Such deposition translates into a supply of new nutrients and trace metals for the surface waters that likely impact biogeochemical cycles. However, the relative impacts of the processes involved are still far from being assessed in situ. After summarizing the knowledge on dust deposition and its impact on the Mediterranean Sea biogeochemistry, we present in this context the objectives and strategy of the PEACETIME project and cruise. Atmospheric and marine in situ observations and process studies have been conducted in contrasted areas encountering different atmospheric deposition context, including a dust deposition event that our dedicated “fast-action” strategy allowed us to catch. Process studies also include artificial dust seeding experiments conducted on board in large tanks in three ecoregions of the open waters of the Mediterranean Sea for the first time. This paper summarizes the work performed at sea and the type of data acquired in the atmosphere, at the air–sea interface and in the water column. An overview of the results presented in papers of this special issue (and in some others published elsewhere) is presented.

scholarly journals Estimating chemical composition of atmospheric deposition fluxes from mineral insoluble particles deposition collected in the Western Mediterranean region

2017 ◽  
Author(s):  
Yinghe Fu ◽  
Karine Desboeufs ◽  
Julie Vincent ◽  
Elisabeth Bon Nguyen ◽  
Benoit Laurent ◽  
...  
Keyword(s):  
Trace Metals ◽  
Chemical Analysis ◽  
Atmospheric Deposition ◽  
Wet Deposition ◽  
Mediterranean Basin ◽  
Mineral Dust ◽  
Western Mediterranean ◽  
Dust Deposition ◽  
Deposition Fluxes ◽  
Western Mediterranean Basin

Abstract. In order to measure the mass flux of atmospheric insoluble deposition and to constrain regional models dust simulation, a network of automatic deposition collectors (CARAGA) has been installed throughout the western Mediterranean basin. Weekly samples of the insoluble fraction of total atmospheric deposition were collected concurrently on filters at 5 sites including 4 on western Mediterranean islands (Frioul and Corsica, France, Mallorca, Spain, and Lampedusa, Italy), and 1 in the southern French Alps (Le Casset), and a weighing and ignition protocol was applied in order to quantify their mineral fraction. Atmospheric deposition is both a strong source of nutrients and metals for marine ecosystems in this area. However, there is little data on trace metal deposition in the literature since their deposition measurement is difficult to perform. In order to obtain more information from CARAGA atmospheric deposition samples, this study aimed at testing their relevance to estimate elemental fluxes in addition to total fluxes. The elemental chemical analysis of ashed CARAGA filter samples was based on an acid digestion and an elemental analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and mass spectrometry (MS) in a clean room. The sampling and analytical protocols were tested to determine the elemental composition for mineral dust tracers (Al, Ca, K, Mg, and Ti), nutrients (P and Fe), and trace metals (Cd, Co, Cr, Cu, Mn, Ni, V and Zn) from simulated wet deposition of dust analogues and traffic soot. The relative mass loss by dissolution in wet deposition was lower than 1 % for Al and Fe, and reached 13 % for P due to its larger solubility in water. For trace metals, this loss represented less than 3 % of the total mass concentration, except for Zn, Cu and Mn for which it could reach 10 %, especially in traffic soot. The chemical contamination during analysis was negligible for all the elements except for Cd which is in very low concentration in dust. Tests allowed us to conclude that the CARAGA samples could be used to estimate contents of nutrients and trace metals in the limits of loss by dissolution. Chemical characterization of CARAGA deposition samples corresponding to the most intense dust deposition events recorded between 2011 and 2013 has been performed and showed elemental mass ratios consistent with the ones found in the literature for Saharan dust. However, the chemical analysis of CARAGA samples revealed the presence of some anthropogenic signatures, as for instance high Zn concentrations in some samples in Lampedusa, and also pointed out that mineral dust can be mixed with anthropogenic compounds in the deposition samples collected on the Frioul Island. Results showed that the chemical analysis of CARAGA ashed samples can be used to trace back origins of elemental deposition. The elemental atmospheric fluxes estimated from these chemical analyses of samples from the CARAGA network of weekly deposition monitoring constitute the first assessment of mass deposition fluxes of trace metals and P during intense dust deposition events at the scale of the western Mediterranean basin.

scholarly journals Process studies at the air-sea interface after atmospheric deposition in the Mediterranean Sea: objectives and strategy of the PEACETIME oceanographic campaign (May–June 2017)

2020 ◽  
Author(s):  
Cécile Guieu ◽  
Fabrizio D'Ortenzio ◽  
François Dulac ◽  
Vincent Taillandier ◽  
Andrea Doglioli ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Mediterranean Sea ◽  
Saharan Dust ◽  
Anthropogenic Sources ◽  
Dust Deposition ◽  
Process Studies ◽  
In Situ Observations ◽  
The Mediterranean ◽  
First Time

Abstract. In spring, the Mediterranean Sea, a well-stratified low nutrient low chlorophyll region, receives atmospheric deposition both desert dust from the Sahara and airborne particles from anthropogenic sources. Such deposition translates into a supply of new nutrients and trace metals for the surface waters that likely impact biogeochemical cycles. However, the quantification of the impacts and the processes involved are still far from being assessed in situ. In this paper, we provide a state of the art regarding dust deposition and its impact on the Mediterranean Sea biogeochemistry and we describe in this context the objectives and strategy of the PEACETIME project and cruise, entirely dedicated to filling this knowledge gap. Our strategy to go a step forward than in previous approaches in understanding these impacts by catching a real deposition event at sea is detailed. The PEACETIME oceanographic campaign took place in May–June 2017 and we describe how we were able to successfully adapt the planned transect in order to sample a Saharan dust deposition event, thanks to a dedicated strategy, so-called Fast Action. That was successful, providing, for the first time in our knowledge, a coupled atmospheric and oceanographic sampling before, during and after an atmospheric deposition event. Atmospheric and marine in situ observations and process studies have been conducted in contrasted area and we summarize the work performed at sea, the type of data acquired and their valorization in the papers published in the special issue.

Atmospheric Chemistry and Deposition

2001 ◽  
Author(s):  
Herman Sievering
Keyword(s):  
Atmospheric Deposition ◽  
Atmospheric Chemistry ◽  
N Deposition ◽  
Anthropogenic Sources ◽  
Alpine Tundra ◽  
Subalpine Forest ◽  
Ecological Processes ◽  
N Accumulation ◽  
Niwot Ridge ◽  
Carbon Dioxide Co2

The two most significant elements with atmospheric components that influence ecological processes at Niwot Ridge are carbon (C) and nitrogen (N). The enrichment of the atmosphere by carbon dioxide (CO2) is ubiquitous across the globe. Global and regional patterns of the annual increases in atmospheric CO2 as well as the current and anticipated vegetation responses are the subject of ongoing analyses (e.g., Schimel 1995, 1998). Hence, except to emphasize the unique Niwot Ridge contribution to the CO2 database, the material presented in this chapter focuses primarily on N, which has a tremendous potential to influence the structure and function of ecosystems (Vitousek et al. 1997). Anthropogenic increases in atmospheric deposition can have profound effects on terrestrial and aquatic ecosystems (Ollinger et al. 1993). Of particular concern are increases in the deposition of nitrogen-containing species, including nonprecipitative, dry-deposited gaseous and particulate N, which can be an important component of the N cycle. These species may act as fertilizer N and can be utilized by vegetation and microbes with little or no energy expenditure. Estimation of the magnitude of N dry plus wet deposition to alpine tundra and subalpine forest ecosystems of Niwot Ridge is integral to understanding N cycling within these systems. This chapter focuses on the estimation of N deposition to the alpine tundra and, to a lesser extent, to the adjacent subalpine forest. The first section presents a brief review of the chemistry of the air environment over Niwot Ridge. The next section discusses the processes of N deposition and exchange with the alpine landscape, source regions for the N in the air over Niwot Ridge, and a procedure for determining atmospheric deposition from ambient air concentrations. Evidence is presented that anthropogenic sources contribute the majority of N in regional air masses and thus to total N deposition. The role that ammonia gas may play in reducing or enhancing N deposition is also described. The contribution that N deposition may make to N accumulation in the subalpine forest ecosystem below Niwot Ridge is briefly discussed in the final section.

scholarly journals Quantification of iron-rich volcanogenic dust emissions and deposition over ocean from Icelandic dust sources

2014 ◽  
Vol 11 (4) ◽  
pp. 5941-5967 ◽  
Author(s):  
O. Arnalds ◽  
H. Olafsson ◽  
P. Dagsson-Waldhauserova
Keyword(s):  
Large Scale ◽  
Dust Emission ◽  
Dust Storms ◽  
Dust Deposition ◽  
Dust Emissions ◽  
Dust Sources ◽  
Basaltic Composition ◽  
Limiting Nutrient ◽  
Dust Events ◽  
Event Based

Abstract. Iceland has extremely active dust sources that result in large scale emissions and deposition on land and sea. The dust has volcanogenic origin of basaltic composition with about 10 % Fe content. We used two independent methods to quantify dust emission from Iceland and dust deposition on sea. Firstly, aerial extent (map) of deposition on land was extended to ocean areas around Iceland. Secondly, survey of number of dust events over the past decades and calculations of emissions and sea deposition for the dust storms were made. The results show total emissions range from 30.5 (dust event based calculation) to 40.1 million tons (map calculation), which places Iceland among the most active dust sources on Earth. Ocean deposition ranges between 5.5 (dust events calculations) and 13.8 million tons (map calculation). Calculated iron deposition from Icelandic dust ranges between 0.56 to 1.4 million tons, which are distributed over wide areas (> 370 000 km2) and consist of fine reactive volcanic materials. The paper provides the first quantitative estimate of total dust emissions and oceanic deposition from Iceland. Iron is a limiting nutrient for primary production in the oceans around Iceland and the dust is likely to affect Fe levels in Icelandic ocean waters.

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