Distribution and behaviour of some dissolved trace metals in the western Mediterranean Sea

Morley, Nick; Burton, J. D.; Tankéré, S.P.C.; Martin, Jean Marie

doi:10.1016/s0967-0645(96)00098-7

Cited by 72 publications

(45 citation statements)

References 25 publications

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“…Total Fe concentrations in both unfiltered and filtered water samples (b100 nm) from the cold CO 2 seeps in Vulcano (Southern Italy) were about an order of magnitude higher than reported for other near-shore oligotrophic Mediterranean waters (Özturk et al, 2003;Sarthou and Jeandel, 2001;Morley et al, 1997), strongly indicating that this type of cold, shallow CO 2 seeps can supply significant iron input to the sea. At such high concentrations (e.g.…”

Section: Discussionmentioning

confidence: 65%

“…opening the narrow necked flasks at about 50 cm below the water surface in order to avoid sampling any surface films (Morley et al, 1997) and to allow CO 2 dissolution through the water column. Simultaneously snapshot values of physico-chemical parameters were recorded (Table 1) using a hand held multi-parameter water quality meter (WTW).…”

Section: Water Sampling For Multi-element Analysis Using Icp-ms and Imentioning

confidence: 99%

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Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

et al. 2012

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a b s t r a c t a r t i c l e i n f oWe report on metal enrichment along a natural pH gradient owing to increased CO 2 degassing at cold, shallow seeps of Vulcano Island in the Mediterranean Sea, off Sicily. We assessed composition of unfiltered and filtered seawater (b100 nm) along acidic zones ranging between ambient and pH 5, and showed that most seep derived elements are present as nanoclusters which then aggregate into larger colloids while mixing with ambient seawater along a pH gradient. Size and elemental composition of such naturally occurring nanoparticles assessed by modern characterisation methods were in good agreement with the results from conventional analytical methods. We provide analytical evidence for the presence in the water column of a large fraction of seep derived elements (e.g. approximately 50% of iron, over 80% of Mn, 100% of Cr, S and Zn) in the form of nano sized particles (e.g. b 100 nm) even at typical open ocean pHs. We launch in situ sampling protocols and sample preparation procedures for multi-method suitable to obtain accurate measurements on nanoparticles from environmental samples. Based on our results a first insight to the formation of natural nanoparticles at cold CO 2 seeps is presented and the persistence of such nano-clusters in the surrounding seawater is stipulated.

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Section: Discussionmentioning

confidence: 65%

Section: Water Sampling For Multi-element Analysis Using Icp-ms and Imentioning

confidence: 99%

Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

et al. 2012

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“…in all cores, it is normal that its evolution below the sediment-water interface recalls the values of these two metals. Indeed, copper is bound to organic matter by passive or active adsorption (Szefer 1991) when brought to the sediment surface, as in the case of the Mejerda Delta (Essoni 1998) and usually in shallow marine environments (Helland and Torgeir 2002;Morel and Hering 1993).…”

Section: Discussionmentioning

confidence: 99%

Diagenetic processes and sediment–water exchanges of heavy metals in the Mejerda River Delta (Gulf of Tunis)

Hellali

Zaaboub²,

Oueslati³

et al. 2015

Environ Earth Sci

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An in situ benthic flux study of iron (Fe), manganese (Mn), lead (Pb), zinc (Zn), cadmium (Cd), copper (Cu) and cobalt (Co) was conducted at three stations at the Mejerda River outlet in the Gulf of Tunis, at depths of 10, 20 and 40 m in March and August 2012. Simultaneously, three sedimentary cores were taken at the same locations to evaluate the diffusive flux of these heavy metals and to determine the early diagenetic mechanisms occurring below the sediment-water interface and their impact on heavy metal mobility. The concentrations of Fe 2? in pore waters were similar to those observed in the rest of the Gulf of Tunis; flux, both benthic (275 lmol m -2 day -1 ) and diffusive (9 lmol m -2 day -1 ), confirmed that sediment was a source of Fe 2? for the water column, at least for the 10-and 20-m stations. The diffusive flux of Mn 2? was greater in August (11-14 lmol m -2 day -1 ) than in March (1-2.6 lmol m -2 day -1 ), representing 8-15 % of benthic flux and indicating that, as for Fe, sediment is a source of Mn 2? for the water column, especially in August. Mn 2? is produced before Fe 2? , which corresponds to the overall pattern of early diagenesis. In March, the production of Mn 2? and Fe 2? takes place in the lower layers of the sediment, probably due to agitation and resuspension occurring at the sediment-water interface. The concentrations of Pb 2? and Zn 2? were higher in this study with reference to the corresponding concentrations in the coastal areas, revealing an anthropogenic activity on the Mejerda River, Ghar El Melh Lagoon (old Mejerda outlet) and the Khlij Channel as the main vectors.

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“…Moreover, the bioavailability of those metals, which is probably not directly related to their total dissolved concentrations in the oceans (Ellwood and van den Berg, 2001;Wang et al, 2009;Dupont et al, 2010) is also poorly documented. While a very limited database does exist for some of these metals in the Mediterranean Sea (Boyle et al, 1985;Tankere et al, 1995;Vega and Van den Berg, 1997;Morley et al, 1997), there is no data on the bioavailable fraction of these metals for the Mediterranean waters. Identifying and quantifying those metals in atmospheric deposition and how they impact the distribution in the water column is essential for understanding the spatial and temporal distribution of diazotrophs and N 2 fixing activity in the Mediterranean Sea.…”

Section: Impact Of Saharan Dust Input On N 2 Fixationmentioning

confidence: 99%

Nutrient control of N<sub>2</sub> fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events

et al. 2011

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Abstract.A better understanding of the factors controlling N 2 fixation is a pre-requisite for improving our knowledge on the contribution of N 2 fixation process in the nitrogen cycling. Trace-metal clean nutrient/dust addition bioassays (+P, +PFe, +dust) were performed at three stations located in the western, central and eastern Mediterranean Sea, in summer 2008 as part of the BOUM cruise. The main goals were (1) to investigate the nutrient factor(s) limiting N 2 fixation (uptake of 15 N 2 ) and (2) to evaluate the potential impact of a Saharan dust event on this biological process during the stratification period. Initially, surface waters at the three stations were DIP-depleted (<10 nM) while the DFe concentrations were relatively high (from 1.2 to 2.3 nM) most likely due to atmospheric iron accumulation in the surface mixed layer. At all stations, Saharan dust input relieved the ambient nutrient limitation of the diazotrophic activity as demonstrated by the strong stimulation of N 2 fixation (from 130 % to 430 %). The highest dust stimulation of N 2 fixation was recorded at the station located in the eastern basin. The response of diazotrophic activity to nutrient additions was variable between the sampled stations suggesting a spatial variability of the factor controlling N 2 fixation over the whole basin. At allCorrespondence to: C. Ridame (celine.ridame@upmc.fr) stations, N 2 fixation was not limited by Fe nor co-limited by P and Fe. At the western station, N 2 fixation was DIP limited while at the eastern one, N 2 fixation was first DIP limited, then was limited by one or several chemical element(s) released by dust. Our results demonstrated that a Saharan dust input was able to relieve these successive on going limitations. Very interestingly, at the station located in the central basin, N 2 fixation was not limited by the availability of P yet it was strongly stimulated by dust addition (x3.1). A chemical element or a combination of several, released by the added dust may have been responsible for the observed stimulations of N 2 fixation. These results indicated that Saharan dust pulses to the surface Mediterranean waters, in addition to P and Fe, could be a source of chemical(s) element(s) that are necessary for metabolic processes and therefore influence rates of N 2 fixation.

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Distribution and behaviour of some dissolved trace metals in the western Mediterranean Sea

Cited by 72 publications

References 25 publications

Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

Diagenetic processes and sediment–water exchanges of heavy metals in the Mejerda River Delta (Gulf of Tunis)

Nutrient control of N<sub>2</sub> fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events

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Distribution and behaviour of some dissolved trace metals in the western Mediterranean Sea

Cited by 72 publications

References 25 publications

Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

Diagenetic processes and sediment–water exchanges of heavy metals in the Mejerda River Delta (Gulf of Tunis)

Nutrient control of N&lt;sub&gt;2&lt;/sub&gt; fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events

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Nutrient control of N<sub>2</sub> fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events