Enregistré dans:
| Auteurs principaux: | , , , , , , |
|---|---|
| Format: | Dataset Open Access |
| Langue: | en |
| Publié: |
PANGAEA
2017
|
| Sujets: | |
| Accès en ligne: | https://doi.org/10.1594/PANGAEA.881516 |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1867169122576498688 |
|---|---|
| author | Häggi, Christoph Chiessi, Cristiano Mazur Merkel, Ute Mulitza, Stefan Prange, Matthias Schulz, Michael Schefuß, Enno |
| author_facet | Häggi, Christoph Chiessi, Cristiano Mazur Merkel, Ute Mulitza, Stefan Prange, Matthias Schulz, Michael Schefuß, Enno |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Variations in Amazonian hydrology and forest cover have major consequences for the global carbon and hydrological cycles as well as for biodiversity. Yet, the climate and vegetation history of the lowland Amazon basin and its effect on biogeography remain debated due to the scarcity of suitable high-resolution paleoclimate records. Here, we use the isotopic composition (dD and d13C) of plant-waxes from a high-resolution marine sediment core collected offshore the Amazon River to reconstruct the climate and vegetation history of the integrated lowland Amazon basin for the period from 50,000 to 12,800 yr before present. Our results show that dD values from the Last Glacial Maximum were more enriched than those from Marine Isotope Stage (MIS) 3 and the present-day. We interpret this trend to reflect long-term changes in precipitation and atmospheric circulation, with overall drier conditions during the Last Glacial Maximum. Our results thus suggest a dominant glacial forcing of the climate in lowland Amazonia. In addition to previously suggested thermodynamic mechanisms of precipitation change, which are directly related to temperature, we conclude that changes in atmospheric circulation are crucial to explain the temporal evolution of Amazonian rainfall variations, as demonstrated in climate model experiments. Our vegetation reconstruction based on d13C values shows that the Amazon rainforest was affected by intrusions of savannah or more open vegetation types in its northern sector during Heinrich Stadials, while it was resilient to glacial drying. This suggests that biogeographic patterns in tropical South America were affected by Heinrich Stadials in addition to glacial-interglacial climate variability. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_881516 |
| institution | PANGAEA |
| language | en |
| publishDate | 2017 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Plant-wax isotope values of sediment core GeoB16224-1 Häggi, Christoph Chiessi, Cristiano Mazur Merkel, Ute Mulitza, Stefan Prange, Matthias Schulz, Michael Schefuß, Enno 087-1; AGE; AMADEUS; Center for Marine Environmental Sciences; DEPTH, sediment/rock; French Guiana; GeoB16224-1; Gravity corer (Kiel type); Ice volume corrected; Maria S. Merian; MARUM; Mean values; Mean values, ice volume corrected; MSM20/3; n-Alkane C29, δ13C; n-Alkane C29, δD; n-Alkane C31, δ13C; n-Alkane C31, δD; n-Alkanes C29-C31, δ13C; n-Alkanes C29-C31, δ13C, standard error; n-Alkanes C29-C31, δD; n-Alkanes C29-C31, δD, standard error; SL Variations in Amazonian hydrology and forest cover have major consequences for the global carbon and hydrological cycles as well as for biodiversity. Yet, the climate and vegetation history of the lowland Amazon basin and its effect on biogeography remain debated due to the scarcity of suitable high-resolution paleoclimate records. Here, we use the isotopic composition (dD and d13C) of plant-waxes from a high-resolution marine sediment core collected offshore the Amazon River to reconstruct the climate and vegetation history of the integrated lowland Amazon basin for the period from 50,000 to 12,800 yr before present. Our results show that dD values from the Last Glacial Maximum were more enriched than those from Marine Isotope Stage (MIS) 3 and the present-day. We interpret this trend to reflect long-term changes in precipitation and atmospheric circulation, with overall drier conditions during the Last Glacial Maximum. Our results thus suggest a dominant glacial forcing of the climate in lowland Amazonia. In addition to previously suggested thermodynamic mechanisms of precipitation change, which are directly related to temperature, we conclude that changes in atmospheric circulation are crucial to explain the temporal evolution of Amazonian rainfall variations, as demonstrated in climate model experiments. Our vegetation reconstruction based on d13C values shows that the Amazon rainforest was affected by intrusions of savannah or more open vegetation types in its northern sector during Heinrich Stadials, while it was resilient to glacial drying. This suggests that biogeographic patterns in tropical South America were affected by Heinrich Stadials in addition to glacial-interglacial climate variability. |
| title | Plant-wax isotope values of sediment core GeoB16224-1 |
| topic | 087-1; AGE; AMADEUS; Center for Marine Environmental Sciences; DEPTH, sediment/rock; French Guiana; GeoB16224-1; Gravity corer (Kiel type); Ice volume corrected; Maria S. Merian; MARUM; Mean values; Mean values, ice volume corrected; MSM20/3; n-Alkane C29, δ13C; n-Alkane C29, δD; n-Alkane C31, δ13C; n-Alkane C31, δD; n-Alkanes C29-C31, δ13C; n-Alkanes C29-C31, δ13C, standard error; n-Alkanes C29-C31, δD; n-Alkanes C29-C31, δD, standard error; SL |
| url | https://doi.org/10.1594/PANGAEA.881516 |