Dissolution kinetics of biogenic silica in the water column
Stirred flow-through experiments were conducted for the first time with planktonic biogenic silica (BSi). We investigated the dissolution kinetics of uncleaned and chemically cleaned BSi collected in ocean surface water, sediment traps, and sediments from the Norwegian Sea, the Southern Ocean, and t...
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ftoceanrep:oai:oceanrep.geomar.de:252 2024-09-15T18:26:48+00:00 Dissolution kinetics of biogenic silica in the water column Rickert, Dirk Schlüter, Michael Wallmann, Klaus J. G. 2002 text https://oceanrep.geomar.de/id/eprint/252/ https://oceanrep.geomar.de/id/eprint/252/1/1-s2.0-S0016703701007578-main.pdf https://doi.org/10.1016/S0016-7037(01)00757-8 en eng Elsevier https://oceanrep.geomar.de/id/eprint/252/1/1-s2.0-S0016703701007578-main.pdf Rickert, D., Schlüter, M. and Wallmann, K. J. G. (2002) Dissolution kinetics of biogenic silica in the water column. Geochimica et Cosmochimica Acta, 66 (3). pp. 439-455. DOI 10.1016/S0016-7037(01)00757-8 <https://doi.org/10.1016/S0016-7037%2801%2900757-8>. doi:10.1016/S0016-7037(01)00757-8 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2002 ftoceanrep https://doi.org/10.1016/S0016-7037(01)00757-8 2024-09-04T05:04:40Z Stirred flow-through experiments were conducted for the first time with planktonic biogenic silica (BSi). We investigated the dissolution kinetics of uncleaned and chemically cleaned BSi collected in ocean surface water, sediment traps, and sediments from the Norwegian Sea, the Southern Ocean, and the Arabian Sea. The solubility at 2°C is rather constant (1000 to 1200 μM). The dissolution rates are, however, highly variable, declining with water depth, and phytoplankton reactivity is two to three orders of magnitude higher than pure siliceous oozes. The reactivity decrease correlates well with an increase in the integrated peak intensity ratios of Si-O-Si/Si-OH measured by Fourier transform infrared (FTIR) spectroscopy. The removal of organic or inorganic coatings enhance the reactivity by at least an order of magnitude. Atomic Al/Si ratios of 0.03 to 0.08 in sedimentary diatom frustules decrease significantly to 0.02 as a result of removal of inorganic coatings and detritals present. Near equilibrium, the dissolution rates exhibit a linear dependence on the degree of undersaturation. At higher degrees of undersaturation—that is, at low concentrations of dissolved silica—the dissolution rates of uncleaned samples define a nonlinear trend. The nonlinear kinetics imply that the dissolution of natural BSi is strongly accelerated in silica-depleted surface waters. The FTIR results suggest that internal condensation reactions reduce the amount of surface reaction sites and are partly responsible for the reactivity decrease with depth. The high content of Al in sedimentary BSi is likely caused by precipitation of dissolved silica with Al dissolved from minerals in sediment. Nonbiogenic silica as coatings or detritals are partly responsible for the solubility and reactivity decrease of BSi in sediments. One order of magnitude different rate constants measured in Norwegian Sea and Southern Ocean sediment trap material support the so-called opal paradox—that is, high BSi accumulation rates in sediments in spite of low ... Article in Journal/Newspaper Norwegian Sea Southern Ocean OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Geochimica et Cosmochimica Acta 66 3 439 455 |
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English |
description |
Stirred flow-through experiments were conducted for the first time with planktonic biogenic silica (BSi). We investigated the dissolution kinetics of uncleaned and chemically cleaned BSi collected in ocean surface water, sediment traps, and sediments from the Norwegian Sea, the Southern Ocean, and the Arabian Sea. The solubility at 2°C is rather constant (1000 to 1200 μM). The dissolution rates are, however, highly variable, declining with water depth, and phytoplankton reactivity is two to three orders of magnitude higher than pure siliceous oozes. The reactivity decrease correlates well with an increase in the integrated peak intensity ratios of Si-O-Si/Si-OH measured by Fourier transform infrared (FTIR) spectroscopy. The removal of organic or inorganic coatings enhance the reactivity by at least an order of magnitude. Atomic Al/Si ratios of 0.03 to 0.08 in sedimentary diatom frustules decrease significantly to 0.02 as a result of removal of inorganic coatings and detritals present. Near equilibrium, the dissolution rates exhibit a linear dependence on the degree of undersaturation. At higher degrees of undersaturation—that is, at low concentrations of dissolved silica—the dissolution rates of uncleaned samples define a nonlinear trend. The nonlinear kinetics imply that the dissolution of natural BSi is strongly accelerated in silica-depleted surface waters. The FTIR results suggest that internal condensation reactions reduce the amount of surface reaction sites and are partly responsible for the reactivity decrease with depth. The high content of Al in sedimentary BSi is likely caused by precipitation of dissolved silica with Al dissolved from minerals in sediment. Nonbiogenic silica as coatings or detritals are partly responsible for the solubility and reactivity decrease of BSi in sediments. One order of magnitude different rate constants measured in Norwegian Sea and Southern Ocean sediment trap material support the so-called opal paradox—that is, high BSi accumulation rates in sediments in spite of low ... |
format |
Article in Journal/Newspaper |
author |
Rickert, Dirk Schlüter, Michael Wallmann, Klaus J. G. |
spellingShingle |
Rickert, Dirk Schlüter, Michael Wallmann, Klaus J. G. Dissolution kinetics of biogenic silica in the water column |
author_facet |
Rickert, Dirk Schlüter, Michael Wallmann, Klaus J. G. |
author_sort |
Rickert, Dirk |
title |
Dissolution kinetics of biogenic silica in the water column |
title_short |
Dissolution kinetics of biogenic silica in the water column |
title_full |
Dissolution kinetics of biogenic silica in the water column |
title_fullStr |
Dissolution kinetics of biogenic silica in the water column |
title_full_unstemmed |
Dissolution kinetics of biogenic silica in the water column |
title_sort |
dissolution kinetics of biogenic silica in the water column |
publisher |
Elsevier |
publishDate |
2002 |
url |
https://oceanrep.geomar.de/id/eprint/252/ https://oceanrep.geomar.de/id/eprint/252/1/1-s2.0-S0016703701007578-main.pdf https://doi.org/10.1016/S0016-7037(01)00757-8 |
genre |
Norwegian Sea Southern Ocean |
genre_facet |
Norwegian Sea Southern Ocean |
op_relation |
https://oceanrep.geomar.de/id/eprint/252/1/1-s2.0-S0016703701007578-main.pdf Rickert, D., Schlüter, M. and Wallmann, K. J. G. (2002) Dissolution kinetics of biogenic silica in the water column. Geochimica et Cosmochimica Acta, 66 (3). pp. 439-455. DOI 10.1016/S0016-7037(01)00757-8 <https://doi.org/10.1016/S0016-7037%2801%2900757-8>. doi:10.1016/S0016-7037(01)00757-8 |
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info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/S0016-7037(01)00757-8 |
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