Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical Calibration
Abstract Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial cell membrane lipids that, when preserved in sedimentary archives, can be used to infer continental paleotemperatures. Although commonly used global calibrations capture a relationship between the distribution of brGDGTs...
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| Format: | Article |
| Language: | English |
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Wiley
2020-08-01
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| Series: | Geochemistry, Geophysics, Geosystems |
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| Online Access: | https://doi.org/10.1029/2020GC008941 |
| _version_ | 1797638175798067200 |
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| author | Lina C. Pérez‐Angel Julio Sepúlveda Peter Molnar Camilo Montes Balaji Rajagopalan Kathryn Snell Catalina Gonzalez‐Arango Nadia Dildar |
| author_facet | Lina C. Pérez‐Angel Julio Sepúlveda Peter Molnar Camilo Montes Balaji Rajagopalan Kathryn Snell Catalina Gonzalez‐Arango Nadia Dildar |
| author_sort | Lina C. Pérez‐Angel |
| collection | DOAJ |
| description | Abstract Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial cell membrane lipids that, when preserved in sedimentary archives, can be used to infer continental paleotemperatures. Although commonly used global calibrations capture a relationship between the distribution of brGDGTs and temperature, they underestimate temperatures for tropical regions as much as ~16°C. Furthermore, some global calibrations reach saturation at around 24–25°C, and, in general, they have root‐mean‐squared errors (RMSEs ≈ ~4°C) that are too large for them to resolve small variations in paleoclimate variability in tropical regions. We present an in situ regional calibration of soil brGDGTs along altitudinal transects on both flanks of the Eastern Cordillera of Colombia in the northern tropical Andes that spans ~3,200 m in elevation and 17°C and 19°C in mean annual soil and air temperatures, respectively. These new soil and air regional calibrations yield RMSEs of 1.5°C and 1.9°C, respectively. When combined with existing data from elsewhere in the tropics, the integrated data (n = 175) not only fit a linear calibration with a RMSE of 2.7°C but also fit a nonlinear calibration with a RMSE of 2.2°C. These calibrations allow for a more precise and reliable reconstruction of past temperatures in the tropics than global calibrations. |
| first_indexed | 2024-03-11T12:58:37Z |
| format | Article |
| id | doaj.art-7ec5151c6f2045e38fdaa166e37af499 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:58:37Z |
| publishDate | 2020-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-7ec5151c6f2045e38fdaa166e37af4992023-11-03T16:55:28ZengWileyGeochemistry, Geophysics, Geosystems1525-20272020-08-01218n/an/a10.1029/2020GC008941Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical CalibrationLina C. Pérez‐Angel0Julio Sepúlveda1Peter Molnar2Camilo Montes3Balaji Rajagopalan4Kathryn Snell5Catalina Gonzalez‐Arango6Nadia Dildar7Department of Geological Sciences University of Colorado Boulder Boulder CO USADepartment of Geological Sciences University of Colorado Boulder Boulder CO USADepartment of Geological Sciences University of Colorado Boulder Boulder CO USADepartment of Physics and Geosciences Universidad del Norte Barranquilla ColombiaCooperative Institute for Research in Environmental Sciences University of Colorado Boulder Boulder CO USADepartment of Geological Sciences University of Colorado Boulder Boulder CO USADepartment of Biological Sciences Universidad de Los Andes Bogotá ColombiaDepartment of Geological Sciences University of Colorado Boulder Boulder CO USAAbstract Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial cell membrane lipids that, when preserved in sedimentary archives, can be used to infer continental paleotemperatures. Although commonly used global calibrations capture a relationship between the distribution of brGDGTs and temperature, they underestimate temperatures for tropical regions as much as ~16°C. Furthermore, some global calibrations reach saturation at around 24–25°C, and, in general, they have root‐mean‐squared errors (RMSEs ≈ ~4°C) that are too large for them to resolve small variations in paleoclimate variability in tropical regions. We present an in situ regional calibration of soil brGDGTs along altitudinal transects on both flanks of the Eastern Cordillera of Colombia in the northern tropical Andes that spans ~3,200 m in elevation and 17°C and 19°C in mean annual soil and air temperatures, respectively. These new soil and air regional calibrations yield RMSEs of 1.5°C and 1.9°C, respectively. When combined with existing data from elsewhere in the tropics, the integrated data (n = 175) not only fit a linear calibration with a RMSE of 2.7°C but also fit a nonlinear calibration with a RMSE of 2.2°C. These calibrations allow for a more precise and reliable reconstruction of past temperatures in the tropics than global calibrations.https://doi.org/10.1029/2020GC008941Andesbranched GDGTsColombiasoilstemperature calibrationtropics |
| spellingShingle | Lina C. Pérez‐Angel Julio Sepúlveda Peter Molnar Camilo Montes Balaji Rajagopalan Kathryn Snell Catalina Gonzalez‐Arango Nadia Dildar Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical Calibration Geochemistry, Geophysics, Geosystems Andes branched GDGTs Colombia soils temperature calibration tropics |
| title | Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical Calibration |
| title_full | Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical Calibration |
| title_fullStr | Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical Calibration |
| title_full_unstemmed | Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical Calibration |
| title_short | Soil and Air Temperature Calibrations Using Branched GDGTs for the Tropical Andes of Colombia: Toward a Pan‐Tropical Calibration |
| title_sort | soil and air temperature calibrations using branched gdgts for the tropical andes of colombia toward a pan tropical calibration |
| topic | Andes branched GDGTs Colombia soils temperature calibration tropics |
| url | https://doi.org/10.1029/2020GC008941 |
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