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Volcanic ash as an oceanic iron source and sink
Author(s) -
Rogan Nicholas,
Achterberg Eric P.,
Le Moigne Frédéric A. C.,
Marsay Chris M.,
Tagliabue Alessandro,
Williams Richard G.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl067905
Subject(s) - scavenging , volcanic ash , volcano , sink (geography) , deposition (geology) , tephra , saturation (graph theory) , environmental chemistry , environmental science , particulates , geology , mineralogy , geochemistry , chemistry , geomorphology , sediment , biochemistry , cartography , mathematics , organic chemistry , combinatorics , geography , antioxidant
Volcanic ash deposition to the ocean forms a natural source of iron (Fe) to surface water microbial communities. Inputs of lithogenic material may also facilitate Fe removal through scavenging. Combining dissolved Fe (dFe) and thorium‐234 observations alongside modeling, we investigate scavenging of Fe in the North Atlantic following the Eyjafjallajökull volcanic eruption. Under typical conditions biogenic particles dominate scavenging, whereas ash particles dominate during the eruption. The size of particles is important as smaller scavenging particles can become saturated with surface‐associated ions. Model simulations indicate that ash deposition associated with Eyjafjallajökull likely led to net Fe removal. Our model suggests a threefold greater stimulation of biological activity if ash deposition had occurred later in the growing season when the region was Fe limited. The implications of ash particle scavenging, eruption timing, and particle saturation need to be considered when assessing the impact of ash deposition on the ocean Fe cycle and productivity.