Importance of the biogenic organic matter in photo-formation of dissolved gaseous mercury in a culture of the marine diatom Chaetoceros sp.

Lanzillotta, E.; Ceccarini, C.; Ferrara, R.; Dini, Fernando; Frontini, Francesco Paolo; Banchetti, Rosalba

doi:10.1016/s0048-9697(03)00400-5

Cited by 43 publications

(16 citation statements)

References 43 publications

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“…These results clearly demonstrate the significant contribution of living cells in mercury volatilization. The DGM production in the culture medium was higher in the light compared to the dark, as expected from the contribution of the biogenic organic matter in photochemical reactions of Hg reduction (Costa and Liss, 1999;Lanzillotta et al, 2004). Our results also show that, in our experimental conditions, the contribution of the live cells to DGM production seems to be independent of the light, being 4.6 ± 0.8 pmol L -1 h -1 in the light and 4.5 ± 0.9 pmol L -1 h -1 in dark conditions.…”

Section: Production Of Dgm In Cultures Of T Weissflogiimentioning

confidence: 69%

“…Field and laboratory studies suggest that, besides bacteria, phytoplankton can play an important role in the processes of the formation of DGM, through an indirect contribution due to the release of biogenic organic matter involved in the photochemical reactions of DGM production, as well as through a cellular direct reduction (Mason et al, 1995;Devars et al, 2000;Lanzillotta et al, 2004;Poulain et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Changes in the non-protein thiol pool and production of dissolved gaseous mercury in the marine diatom Thalassiosira weissflogii under mercury exposure

Morelli

Ferrara

Bellini

et al. 2009

Science of The Total Environment

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Two detoxification mechanisms working in the marine diatom Thalassiosira weissfloggii to cope with mercury toxicity were investigated. Initially, the effect of mercury on the intracellular pool of non-protein thiols was studied in exponentially growing cultures exposed to sub-toxic HgCl 2 concentrations. T. weissfloggii cells responded by synthesizing metalbinding peptides, named phytochelatins (PCs), besides increasing the intracellular pool of glutathione and γ-glutamylcysteine (γ-EC). Intracellular Hg and PC concentrations increased with the Hg concentration in the culture medium, exhibiting a distinct dose-response relationship. However, considerations of the PCs-SH:Hg molar ratio suggest that also glutathione could be involved in the intracellular mercury sequestration. The time course of the non-protein thiol pool and Hg intracellular concentration shows that PCs, glutathione and γ-EC represent a rapid cellular response to mercury, although their role in Hg detoxification seems to lose importance at longer incubation times. The occurrence of a process of reduction of Hg(II) to Hg° and subsequent production of dissolved gaseous mercury (DGM) was also investigated at lower Hg concentrations, at which the PC synthesis doesn't seem to be involved. The significant (P<0.01) correlation between the cellular density in solution and the production of DGM suggests that this diatom is capable of directly producing DGM, both in light and dark conditions. This finding has been confirmed by the absence of DGM production in the culture media containing formaldehyde-killed cells. Finally, the relationship between these two different pathways of Hg detoxification is discussed.

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Section: Production Of Dgm In Cultures Of T Weissflogiimentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Changes in the non-protein thiol pool and production of dissolved gaseous mercury in the marine diatom Thalassiosira weissflogii under mercury exposure

Morelli

Ferrara

Bellini

et al. 2009

Science of The Total Environment

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“…Among all factors, the solar radiation (Amyot et al, 1997;Lanzillotta et al, 2002;Rolfhus and Fitzgerald, 2004) and microorganism activities (Mason et al, 1995;Lanzillotta et al, 2004;Poulain et al, 2004;Fantozzi, et al, 2009) are considered as the principal forces for the RHg reduction to DGM. The high DGM levels in this cruise and elevated levels near coast might be explained as follows.…”

Section: Dgm Concentrationsmentioning

confidence: 99%

Distribution and air-sea exchange of mercury (Hg) in the Yellow Sea

Zhang²,

Wang³

et al. 2011

Atmos. Chem. Phys.

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Abstract. The Yellow Sea, surrounded by East China and the Korea Peninsula, is a potentially important receptor for anthropogenic mercury (Hg) emissions from East Asia. However, there is little documentation about the distribution and cycle of Hg in this marine system. During the cruise covering the Yellow Sea in July 2010, gaseous elemental mercury (GEM or Hg(0)) in the atmosphere, total Hg (THg), reactive Hg (RHg) and dissolved gaseous mercury (DGM, largely Hg(0)) in the waters were measured aboard the R/V Kexue III. The mean (±SD) concentration of GEM over the entire cruise was 2.61 ± 0.50 ng m −3 (range: 1.68 to 4.34 ng m −3 ), which were generally higher than other open oceans. The spatial distribution of GEM generally reflected a clear gradient with high levels near the coast of East China and low levels in open waters, suggesting the significant atmospheric Hg outflow from East China. The mean concentration of THg in the surface waters was 1.69 ± 0.35 ng l −1 and the RHg accounted for a considerable fraction of THg (RHg: 1.08 ± 0.28 ng l −1 , %RHg/THg = 63.9%). The mean concentration of DGM in the surface waters was 63.9 ± 13.7 pg l −1 and always suggested the supersaturation of Hg(0) in the surface waters with respect to Hg(0) in the atmosphere (the degree of saturation: 7.8 ± 2.3 with a range of 3.6-14.0). The mean Hg(0) flux at the air-sea interface was estimated to be 18.3 ± 11.8 ng m −2 h −1 based on a two-layer exchange model. The high wind speed and DGM levels induced the extremely high Hg(0) emission rates. Measurements at three stations showed no clear vertical patterns of DGM, RHg and THg in the water column. Overall, the elevated Hg levels in the Yellow Sea compared with other open oceans suggested that the human activity has influenced the oceanic Hg cycle downwind of East Asia.

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“…The activity of bacterial mercuric reductase may play a role in DGM production (Barkay et al 1991;Siciliano et al 2002), and photosynthetic organisms such as algae can induce DGM production (Poulain et al 2004). Lanzillotta et al (2004) suggested that mainly biogenic organic compounds released by the cell in the culture medium contribute to DGM photoproduction. Amyot et al (1997a) also showed that DGM was produced in filtered (0.7 μm) water at rates similar to that in unfiltered water under natural sunlight, indicating that microorganisms were not a significant DGM producer.…”

Section: Introductionmentioning

confidence: 99%

Effect of Abiotic and Biotic Factors on the Photo-Induced Production of Dissolved Gaseous Mercury

Kim

Lee

et al. 2011

Water Air Soil Pollut

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This study was conducted to evaluate the contribution of environmental factors such as solar radiation and dissolved organic matter (DOM) on the photo-induced dissolved gaseous mercury (DGM) production through laboratory experiments using field water samples collected from wetlands. DGM production was more significantly influenced by UVB intensity than UVA. DGM formation was also significantly affected by DOM chemical structure/ composition rather than its concentration. Increasing NO 3 − concentration limited DGM production, but photo-induced Hg oxidation stimulated by NO 3 − would possibly occur when the NO 3 − level is more than twice the DOC level. The addition of phosphorus into the field water samples induced a slight increase of DGM production; however, the addition of nitrogen decreased DGM formation, suggesting that an increase of limiting nutrients in water may promote biotic DGM production. Experiments using a Selenastrum capricornutum monoculture solution showed that cell density had a positive effect on DGM production. Moreover, the difference in DGM production between filtered and unfiltered samples showed that S. capricornutum significantly produced biotic DGM under UVA irradiation. Finally, our results imply that environmental factors such as light intensity, DOM sources, and site-specific microorganisms can significantly affect photo-induced Hg transformation.

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Importance of the biogenic organic matter in photo-formation of dissolved gaseous mercury in a culture of the marine diatom Chaetoceros sp.

Cited by 43 publications

References 43 publications

Changes in the non-protein thiol pool and production of dissolved gaseous mercury in the marine diatom Thalassiosira weissflogii under mercury exposure

Changes in the non-protein thiol pool and production of dissolved gaseous mercury in the marine diatom Thalassiosira weissflogii under mercury exposure

Distribution and air-sea exchange of mercury (Hg) in the Yellow Sea

Effect of Abiotic and Biotic Factors on the Photo-Induced Production of Dissolved Gaseous Mercury

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