Branched GDGTs in the Tagus River drainage basin and its outflow into the Atlantic Ocean
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| Sprache: | en |
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PANGAEA
2016
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| author | Warden, Lisa Kim, Jung-Hyun Zell, Claudia Vis, Geert-Jan de Stigter, Henko Bonnin, Jerome Sinninghe Damsté, Jaap S |
| author_facet | Warden, Lisa Kim, Jung-Hyun Zell, Claudia Vis, Geert-Jan de Stigter, Henko Bonnin, Jerome Sinninghe Damsté, Jaap S |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | The distributions of branched glycerol dialkyl glycerol tetraethers (brGDGTs), which are transported from the soils where they are predominantly produced to marine sediments via rivers, have been applied in reconstructing mean annual air temperature (MAT) and pH of soils. However, paleoclimate reconstructions using sedimentary brGDGTs have proven difficult in arid regions, including the Iberian Peninsula. Recently, six novel 6-methyl brGDGTs have been described using new analytical methods (in addition to the nine 5-methyl brGDGTs previously used for climate reconstructions), and so new pH and MAT calibrations have been developed that were shown to improve the accuracy of reconstructions in a set of global soil samples, especially in arid regions. Because of this we decided to apply the new method to separate the 5- and 6-methyl isomers along with the novel calibrations to a sample set from the Iberian Peninsula to determine whether it improves paleoclimate reconstructions in this area. This set includes samples that run in a transect from source to sink along the Tagus River and out to the deep ocean off the Portuguese margin spanning the last 6000 years. We found that although pH reconstructions in the soils were improved using the new calibration, MAT reconstructions were not much better even with the separation of the 5- and 6-methyl brGDGTs. This confirmed the conclusion of previous studies that the amount of aquatically produced brGDGTs is overwhelming the soil-derived ones in marine sediments and complicating MAT reconstructions in the region. Additionally, the newseparation revealed a strong and until now unseen relationship between the new degree of cyclization (DC') of the brGDGTs and MAT that could be making temperature reconstructions in this and other arid regions difficult |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_881561 |
| institution | PANGAEA |
| language | en |
| publishDate | 2016 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Branched GDGTs in the Tagus River drainage basin and its outflow into the Atlantic Ocean Warden, Lisa Kim, Jung-Hyun Zell, Claudia Vis, Geert-Jan de Stigter, Henko Bonnin, Jerome Sinninghe Damsté, Jaap S NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University The distributions of branched glycerol dialkyl glycerol tetraethers (brGDGTs), which are transported from the soils where they are predominantly produced to marine sediments via rivers, have been applied in reconstructing mean annual air temperature (MAT) and pH of soils. However, paleoclimate reconstructions using sedimentary brGDGTs have proven difficult in arid regions, including the Iberian Peninsula. Recently, six novel 6-methyl brGDGTs have been described using new analytical methods (in addition to the nine 5-methyl brGDGTs previously used for climate reconstructions), and so new pH and MAT calibrations have been developed that were shown to improve the accuracy of reconstructions in a set of global soil samples, especially in arid regions. Because of this we decided to apply the new method to separate the 5- and 6-methyl isomers along with the novel calibrations to a sample set from the Iberian Peninsula to determine whether it improves paleoclimate reconstructions in this area. This set includes samples that run in a transect from source to sink along the Tagus River and out to the deep ocean off the Portuguese margin spanning the last 6000 years. We found that although pH reconstructions in the soils were improved using the new calibration, MAT reconstructions were not much better even with the separation of the 5- and 6-methyl brGDGTs. This confirmed the conclusion of previous studies that the amount of aquatically produced brGDGTs is overwhelming the soil-derived ones in marine sediments and complicating MAT reconstructions in the region. Additionally, the newseparation revealed a strong and until now unseen relationship between the new degree of cyclization (DC') of the brGDGTs and MAT that could be making temperature reconstructions in this and other arid regions difficult |
| title | Branched GDGTs in the Tagus River drainage basin and its outflow into the Atlantic Ocean |
| topic | NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University |
| url | https://doi.org/10.1594/PANGAEA.881561 |