Possible impacts of volcanic ash emissions of Mount Etna on the primary productivity in the oligotrophic Mediterranean Sea: Results from nutrient-release experiments in seawater

Olgun, Nazlı; Duggen, Svend; Andronico, Daniele; Kutterolf, Steffen; Croot, Peter; Giammanco, Salvatore; Censi, P.; Randazzo, Loredana

doi:10.1016/j.marchem.2013.04.004

Cited by 77 publications

(33 citation statements)

References 72 publications

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“…Mobilization of 0.03-0.15 % of the iron at the ash surface (as in the reference scenario) according to Eq. (3) means 5-134 nmol Fe g −1 ash which is close to the measured iron released from Kasatochi ash (61-81 nmol Fe g −1 ) reported by Olgun et al (2013b). Although the fate and speciation of the dissolved iron depend on further in-cloud processes, the calculations above indicate that even a very small percentage of mobilized iron in the ash means a huge mass with potentially significant impacts on the receiving environment.…”

Section: Comparison With Experimental Datasupporting

confidence: 79%

“…This phytoplankton bloom was indeed the first direct evidence of a fertilization effect of volcanic ash iron on the surface ocean (Langmann et al, 2010;Hamme et al, 2010). While small-scale ash iron fertilization events (e.g., after the Eyjafjallajökull eruption in 2010, Iceland) trigger perturbations in the local marine biogeochemistry (Olgun et al, 2013b;Achterberg et al, 2013), large-scale events (e.g., the 1991 eruption of Mt. Pinatubo, Philippines) may stimulate the MPP and, in turn, the atmospheric CO 2 drawdown globally (Sarmiento, 1993;Watson, 1997) with significant impacts on the climate system (Robock, 2000).…”

Section: Introductionmentioning

confidence: 79%

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Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

2015

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Abstract. It has been shown that volcanic ash fertilizes the Fe-limited areas of the surface ocean through releasing soluble iron. As ash iron is mostly insoluble upon the eruption, it is hypothesized that heterogeneous in-plume and in-cloud processing of the ash promote the iron solubilization. Direct evidences concerning such processes are, however, lacking. In this study, a 1-D numerical model is developed to simulate the physicochemical interactions of the gas-ash-aerosol in volcanic eruption plumes focusing on the iron mobilization processes at temperatures between 600 and 0 • C. Results show that sulfuric acid and water vapor condense at ∼ 150 and ∼ 50 • C on the ash surface, respectively. This liquid phase then efficiently scavenges the surrounding gases (> 95 % of HCl, 3-20 % of SO 2 and 12-62 % of HF) forming an extremely acidic coating at the ash surface. The low pH conditions of the aqueous film promote acid-mediated dissolution of the Fe-bearing phases present in the ash material. We estimate that 0.1-33 % of the total iron available at the ash surface is dissolved in the aqueous phase before the freezing point is reached. The efficiency of dissolution is controlled by the halogen content of the erupted gas as well as the mineralogy of the iron at ash surface: elevated halogen concentrations and presence of Fe 2+ -carrying phases lead to the highest dissolution efficiency. Findings of this study are in agreement with the data obtained through leaching experiments.

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Section: Comparison With Experimental Datasupporting

confidence: 79%

Section: Introductionmentioning

confidence: 79%

Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

2015

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“…These shales were deposited synchronously across the Yangtze Sea in response to increasing deepwater restriction linked to Kwangsian tectonism (Chen et al, 2014) in combination with increases in marine productivity triggered by terrigenous nutrient inputs (See Section 6.3; Chen et al, 2011;Yan et al, 2012). Moreover, high marine productivity can be driven by volcanically sourced nutrients (Dawson, 2000;Su et al, 2003;Jones and Gislason, 2008;Olgun et al, 2013), and the Wufeng Formation contains abundant volcanic ash beds (Su et al, 2009). These beds record plinian eruptive events from a syn-collisional volcanic arc on the southeastern margin of the Yangtze Platform (related to convergence of the Yangtze and Cathaysia Blocks) based on analysis of K-bentonite compositions (Su et al, 2006(Su et al, , 2009.…”

Section: Implications For Organic Accumulation In O-s Black Shales Onmentioning

confidence: 99%

Global and regional controls on marine redox changes across the Ordovician-Silurian boundary in South China

Liu

Algeo

et al. 2016

Palaeogeography, Palaeoclimatology, Palaeoecology

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The Ordovician-Silurian (O-S) transition coincided with significant environmental and biological changes. In South China, the Yangtze Platform experienced both global and regional events at this time, including sea-level fluctuations, tectonic movements, volcanic eruptions, mass extinction, and widespread anoxia. The O-S transitional strata of the Yangtze Platform comprise organic-rich black shales that are an important oil source rock. To explore the evolution of watermass chemistry and its relationship to organic matter accumulation, we conducted an integrated Fe-S-C geochemical study (i.e., Fe-speciation, δ 13 C org , δ 34 S py , pyrite-S and TOC) of the O-S boundary sections at Datianba (Chongqing Municipality) and Shuanghe (Sichuan Province). These sections were located in the restricted inner Yangtze Sea, in contrast to the previously studied Wangjiawan section, which was deposited in a more open setting of the outer Yangtze Sea. In contrast to the well-oxygenated conditions at Wangjiawan, the Datianba and Shuanghe sections record persistently anoxic, and episodically euxinic, conditions during the Hirnantian, which can be explained by the unique paleogeography and restricted hydrography of the inner Yangtze Sea. We propose that the regional Kwangsian Orogeny, which was driven by collision of the Yangtze and Cathaysia blocks, played a key role in basin development, watermass chemistry changes, and accumulation of Wufeng Formation black shales within the Yangtze Sea. The more widespread black shales of the Lower Silurian Lungmachi Formation were linked to the post-Hirnantian global marine transgression.

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“…Upon interaction with seawater, volcanic ash releases several biologically relevant elements into the seawater (Frogner et al 2001, Duggen et al 2007, Jones & Gislason 2008, Olgun et al 2011, 2013 which may affect phytoplankton growth (Censi et al 2010, Hamme et al 2010, Langmann et al 2010b, Lin et al 2011, Hoffmann et al 2012. Some eruptions can negatively affect the marine environment by releasing acidic aerosols and thus reducing the pH of the seawater (Wall-Palmer et al 2011), or releasing toxic metals (e.g.…”

Section: Introductionmentioning

confidence: 99%

Geochemical evidence of oceanic iron fertilization by the Kasatochi volcanic eruption in 2008 and the potential impacts on Pacific sockeye salmon

Olgun¹,

Duggen²,

Langmann³

et al. 2013

Mar. Ecol. Prog. Ser.

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The Kasatochi volcanic eruption that occurred in the central Aleutian Islands in Alaska, USA, in August 2008 is thought to have induced a massive diatom bloom in the ironlimited waters of the Gulf of Alaska, which potentially affected the oceanic food web by increasing the abundance of zooplankton and sockeye salmon Oncorhynchus nerka in the northeast Pacific Ocean. We report the first seawater experiments involving volcanic ash ejected from the Kasatochi eruption, showing that the ash released 61 to 83 nmol Fe, 374 to 410 nmol NO 3 − , 5 to 6 nmol PO 4 3− and 170 to 585 nmol SiO 2 when it contacted seawater. Our study suggests that the amount of iron released from Kasatochi ash (an increase of 2.0 to 2.8 nM Fe) was indeed sufficient to cause the observed phytoplankton bloom in the northeastern Pacific Gyre, while the impact of macronutrient release was minimal. We further evaluated the multiple, interdependent processes in the oceanic food web related to the diatom bloom, involving the ocean survival of juvenile salmon that entered the northeast Pacific Ocean in the summer of 2008. KEY WORDS: Kasatochi eruption · Volcanic ash · Fe limitation · Diatom bloom · Gulf of Alaska · Sockeye salmon Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 488: 81-88, 2013& Fitzwater 1988, Boyd & Harrison 1999, and sporadically by Si (Wong & Matear 1999, Whitney et al. 2005. It is one of the most volcanically active regions on Earth, containing more than 150 subaerial volcanoes in the Kurile-Kamchatka and Aleutian volcanic arcs, which produce about 10 volcanic eruptions each year (Siebert & Simkin 2002). Due to the high flux of volcanic ash in the North Pacific Ocean, atmospheric deposition of volcanic ash has been considered to be an important external Fe source in the region (Olgun et al. 2011). The fertilizing potential of volcanic eruptions has been previously observed in the North Pacific Ocean region after the eruptions of Miyake-Jima in 2000 and Anatahano in 2003(Uematsu et al. 2004, Lin et al. 2011, and also in the neighboring rivers and lakes during the Mount St. Helens eruption in 1980 (Smith & White 1985).During July-August 2008, 3 explosive volcanic eruptions occurred in the remote Aleutian Islands of Alaska: at Okmok on 12 July, Cleveland on 21 July, and Kasatochi on 7 to 8 August (Waythomas et al. 2008, Larsen et al. 2009, Langmann et al. 2010b). The Kasa tochi volcanic eruption was the largest of the 3 eruptions, producing several ash plumes that reached as high as 18 km above the sea level (Langmann et al. 2010a, Waythomas et al. 2010). An unusual and extensive phytoplankton bloom (covering an area of ca. 1.5 × 10 6 km 2 ) started in the Gulf of Alaska a few days after the Kasatochi eruption ( Fig. 1), and this bloom has been related to Fe-fertilization by Kasatochi ash fallout (Hamme et al. 2010, Langmann et al. 2010b. The mean chlorophyll a (chl a) values in August 2008 were 2 to 3 times higher than the usual values for this time of year (Hamme et al. 2010...

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Possible impacts of volcanic ash emissions of Mount Etna on the primary productivity in the oligotrophic Mediterranean Sea: Results from nutrient-release experiments in seawater

Cited by 77 publications

References 72 publications

Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

Global and regional controls on marine redox changes across the Ordovician-Silurian boundary in South China

Geochemical evidence of oceanic iron fertilization by the Kasatochi volcanic eruption in 2008 and the potential impacts on Pacific sockeye salmon

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