A novel approach to investigate the deposition of (bio)chemical sediments: The settling rate of cyanobacteria-ferrihydrite aggregates
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| Formato: | Dataset Open Access |
| Lenguaje: | en |
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PANGAEA
2026
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| _version_ | 1867168204743245824 |
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| author | Li, Yuhao Sutherland, Bruce R Gingras, Murray K Konhauser, Kurt O |
| author_facet | Li, Yuhao Sutherland, Bruce R Gingras, Murray K Konhauser, Kurt O |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Abstract Deposition rates of different chemical sediments are typically calculated using Stokes's law. However, applying it to chemical sediments that form in situ in the water column is not ideal because the particle properties do not fulfil many of the assumptions underpinning the applicability of Stokes' law. As a consequence, it has been difficult to predict the sedimentation rate of ancient chemical sediments, such as Precambrian banded iron formations (BIF), because their primary sediments likely comprised aggregates of ferric hydroxides, such as ferrihydrite [Fe(OH)3], and marine bacterial biomass, including cyanobacteria. In this work we have experimentally attempted to address the mechanisms by which primary BIF sediment, formed by the oxidation of dissolved Fe(II) by O2 and simultaneously incubated with cyanobacterium Synechococcus sp. PCC 7002, were deposited to the Archean ocean. We demonstrate that ferrihydrite-cyanobacteria aggregates settled to the ocean floor either through the formation of uniformly descending concentration-fronts or through convective plumes. The settling mechanism depended on both initial Fe (II) concentration and the pH. Correspondingly, two algorithms were developed to characterise the settling velocity. These algorithms tracked the alteration of light intensity from low to high as sediments descended from an initially homogeneous state through a water tank; and as well calculated the average light intensity over time, from which vertical time series were constructed allowing calculation of the settling velocity. Our method not only provides an accurate estimation of the in situ settling rate of cell-mineral aggregates, but also provides new insights into the physical mechanisms by which the primary sediments composing BIF were deposited. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_918704 |
| institution | PANGAEA |
| language | en |
| publishDate | 2026 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | A novel approach to investigate the deposition of (bio)chemical sediments: The settling rate of cyanobacteria-ferrihydrite aggregates Li, Yuhao Sutherland, Bruce R Gingras, Murray K Konhauser, Kurt O Banded Iron Formation; BIF deposition; Cyanobacteria-ferrihydrite aggregates; settling rate Abstract Deposition rates of different chemical sediments are typically calculated using Stokes's law. However, applying it to chemical sediments that form in situ in the water column is not ideal because the particle properties do not fulfil many of the assumptions underpinning the applicability of Stokes' law. As a consequence, it has been difficult to predict the sedimentation rate of ancient chemical sediments, such as Precambrian banded iron formations (BIF), because their primary sediments likely comprised aggregates of ferric hydroxides, such as ferrihydrite [Fe(OH)3], and marine bacterial biomass, including cyanobacteria. In this work we have experimentally attempted to address the mechanisms by which primary BIF sediment, formed by the oxidation of dissolved Fe(II) by O2 and simultaneously incubated with cyanobacterium Synechococcus sp. PCC 7002, were deposited to the Archean ocean. We demonstrate that ferrihydrite-cyanobacteria aggregates settled to the ocean floor either through the formation of uniformly descending concentration-fronts or through convective plumes. The settling mechanism depended on both initial Fe (II) concentration and the pH. Correspondingly, two algorithms were developed to characterise the settling velocity. These algorithms tracked the alteration of light intensity from low to high as sediments descended from an initially homogeneous state through a water tank; and as well calculated the average light intensity over time, from which vertical time series were constructed allowing calculation of the settling velocity. Our method not only provides an accurate estimation of the in situ settling rate of cell-mineral aggregates, but also provides new insights into the physical mechanisms by which the primary sediments composing BIF were deposited. |
| title | A novel approach to investigate the deposition of (bio)chemical sediments: The settling rate of cyanobacteria-ferrihydrite aggregates |
| topic | Banded Iron Formation; BIF deposition; Cyanobacteria-ferrihydrite aggregates; settling rate |
| url | https://doi.org/10.1594/PANGAEA.918704 |