Geochemistry of sediments and volcanic ash from Southcentral Alaska
Abstract: The subarctic Pacific Ocean and Bering Sea comprise the second-largest high nitrate, low chlorophyll region in the world, where primary production is limited by the availability of iron (Fe). To estimate the potential impact of different terrestrial aerosol Fe sources on marine ecosystems,...
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2021
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dataone:http://get.iedadata.org/metadata/iso/111679 2024-10-03T18:46:01+00:00 Geochemistry of sediments and volcanic ash from Southcentral Alaska Koffman, Bess Yoder, Meg Methven, Taylor Hanschka, Lena Sears, Helen Saylor, Patrick Wallace, Kristi 2021-01-01T00:00:00Z http://get.iedadata.org/metadata/iso/111679 unknown IEDA: EarthChem Library Other Dust, volcanic ash, trace metals, iron fertilization, iron solubility Alaska Interdisciplinary Earth Data Alliance (IEDA) Dataset 2021 dataone:urn:node:IEDA_EARTHCHEM 2024-10-03T18:16:53Z Abstract: The subarctic Pacific Ocean and Bering Sea comprise the second-largest high nitrate, low chlorophyll region in the world, where primary production is limited by the availability of iron (Fe). To estimate the potential impact of different terrestrial aerosol Fe sources on marine ecosystems, we performed a suite of laboratory assessments following established protocols, including: 1) leaching with Milli-Q water, 2) sequential extractions, 3) complete acid digestions, 4) X-ray diffraction, and 5) grain size analysis. Measurements were performed on 20 fine-grained (<5 μm) glacier-derived sediments from Alaska and the Yukon, 2 fresh, never-wetted volcanic ashes (Redoubt 2009 and Pavlof 2016), and 6 weathered ashes (Redoubt and Augustine) which span the past ~8700 years. We compared results to published data on Asian desert-derived sediments, finding that the glacier-derived sediments have five times higher easily-reducible Fe (median 2.3 ± 0.6 wt. %) than desert-derived samples (0.49 ± 0.1 wt. %) and fourteen times higher easily-reducible Fe than fresh ash (0.16 ± 0.1 wt. %). In addition, fractional Fe solubility was higher in glacial sediment (median cumulative 0.31 ± 0.11% FeS) than volcanic ash (0.04 ± 0.02 % FeS). Glacial sediments also contained higher concentrations of bioactive metals including Co, Ni, Cu, Zn, Mo, Cd, and Pb. Inferred Fe availability increased with sample age, pointing to the ability of environmental weathering processes to change Fe geochemistry. Other Description: Koffman, B.G., Yoder, M.F., Methven, T., Hanschka, L., Sears, H.B., Saylor, P.L., Wallace, K.L., (submitted 2020). "Glacial dust surpasses both volcanic ash and desert dust in its iron fertilization potential." Global Biogeochemical Cycles. Dataset Bering Sea glacier Subarctic Alaska Yukon IEDA: EarthChem Library (via DataONE) Bering Sea Pacific Yukon |
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IEDA: EarthChem Library (via DataONE) |
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dataone:urn:node:IEDA_EARTHCHEM |
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Other Dust, volcanic ash, trace metals, iron fertilization, iron solubility Alaska Interdisciplinary Earth Data Alliance (IEDA) |
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Other Dust, volcanic ash, trace metals, iron fertilization, iron solubility Alaska Interdisciplinary Earth Data Alliance (IEDA) Koffman, Bess Yoder, Meg Methven, Taylor Hanschka, Lena Sears, Helen Saylor, Patrick Wallace, Kristi Geochemistry of sediments and volcanic ash from Southcentral Alaska |
topic_facet |
Other Dust, volcanic ash, trace metals, iron fertilization, iron solubility Alaska Interdisciplinary Earth Data Alliance (IEDA) |
description |
Abstract: The subarctic Pacific Ocean and Bering Sea comprise the second-largest high nitrate, low chlorophyll region in the world, where primary production is limited by the availability of iron (Fe). To estimate the potential impact of different terrestrial aerosol Fe sources on marine ecosystems, we performed a suite of laboratory assessments following established protocols, including: 1) leaching with Milli-Q water, 2) sequential extractions, 3) complete acid digestions, 4) X-ray diffraction, and 5) grain size analysis. Measurements were performed on 20 fine-grained (<5 μm) glacier-derived sediments from Alaska and the Yukon, 2 fresh, never-wetted volcanic ashes (Redoubt 2009 and Pavlof 2016), and 6 weathered ashes (Redoubt and Augustine) which span the past ~8700 years. We compared results to published data on Asian desert-derived sediments, finding that the glacier-derived sediments have five times higher easily-reducible Fe (median 2.3 ± 0.6 wt. %) than desert-derived samples (0.49 ± 0.1 wt. %) and fourteen times higher easily-reducible Fe than fresh ash (0.16 ± 0.1 wt. %). In addition, fractional Fe solubility was higher in glacial sediment (median cumulative 0.31 ± 0.11% FeS) than volcanic ash (0.04 ± 0.02 % FeS). Glacial sediments also contained higher concentrations of bioactive metals including Co, Ni, Cu, Zn, Mo, Cd, and Pb. Inferred Fe availability increased with sample age, pointing to the ability of environmental weathering processes to change Fe geochemistry. Other Description: Koffman, B.G., Yoder, M.F., Methven, T., Hanschka, L., Sears, H.B., Saylor, P.L., Wallace, K.L., (submitted 2020). "Glacial dust surpasses both volcanic ash and desert dust in its iron fertilization potential." Global Biogeochemical Cycles. |
format |
Dataset |
author |
Koffman, Bess Yoder, Meg Methven, Taylor Hanschka, Lena Sears, Helen Saylor, Patrick Wallace, Kristi |
author_facet |
Koffman, Bess Yoder, Meg Methven, Taylor Hanschka, Lena Sears, Helen Saylor, Patrick Wallace, Kristi |
author_sort |
Koffman, Bess |
title |
Geochemistry of sediments and volcanic ash from Southcentral Alaska |
title_short |
Geochemistry of sediments and volcanic ash from Southcentral Alaska |
title_full |
Geochemistry of sediments and volcanic ash from Southcentral Alaska |
title_fullStr |
Geochemistry of sediments and volcanic ash from Southcentral Alaska |
title_full_unstemmed |
Geochemistry of sediments and volcanic ash from Southcentral Alaska |
title_sort |
geochemistry of sediments and volcanic ash from southcentral alaska |
publisher |
IEDA: EarthChem Library |
publishDate |
2021 |
url |
http://get.iedadata.org/metadata/iso/111679 |
geographic |
Bering Sea Pacific Yukon |
geographic_facet |
Bering Sea Pacific Yukon |
genre |
Bering Sea glacier Subarctic Alaska Yukon |
genre_facet |
Bering Sea glacier Subarctic Alaska Yukon |
_version_ |
1811923328019988480 |