Jaeschke, Andrea, Rethemeyer, Janet, Lappe, Michael, Schouten, Stefan, Boeckx, Pascal and Schefuss, Enno (2018). Influence of land use on distribution of soil n-alkane delta D and brGDGTs along an altitudinal transect in Ethiopia: Implications for (paleo) environmental studies. Org. Geochem., 124. S. 77 - 88. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 0146-6380
Full text not available from this repository.Abstract
The combined use of plant wax n-alkane delta D values and branched glycerol dialkyl glycerol tetraether lipid (brGDGT) distributions provides a novel approach for paleoaltitude reconstruction. Studies from East Africa revealed, however, inconsistent results between the proxy estimates and altitudinal parameters. Here, we explore these proxies in soils of different land use (forest, cropland and pasture) along an altitudinal transect in the Jimma zone of the southwest Ethiopian highlands to better understand environmental and plant-specific factors controlling the isotopic composition and distribution of n-alkanes and brGDGTs. The hydrogen isotope composition of individual n-alkanes does not unambiguously reflect the altitude effect on precipitation delta D, but seems largely influenced by the specific land use. Only forest soil-derived n-C-27 and n-C-29 alkane delta D values exhibit a significant linear relationship with altitude (r -0.87, p < 0.05), likely reflecting the most stable ecosystem. The resulting lapse rate of -17 parts per thousand/1000 m is comparable with that of local precipitation in the southwest Ethiopian highlands. In addition, the linear correlation of the average chain length (ACL) and delta C-13 values of forest soil n-alkanes suggests a physiological adaptation of the specific plant type waxes to altitude-induced environmental changes in the study area. The distribution of brGDGTs also reveals a significant linear correlation with altitude (r -0.97, p < 0.01), reflecting the decrease in temperature with higher elevation, independent of land use. In addition, brGDGT-based mean annual air temperature (MAT) estimates of 19.5-14.0 degrees C and temperature lapse rate of -6 degrees C/1000 m are in good agreement with direct measurements in the Jimma zone. In contrast to previous studies from East Africa, our results show that both soil n-alkane dD values and brGDGT-based MAT distributions track present day altitude effects on local environmental gradients in the southwest Ethiopian highlands. (C) 2018 Elsevier Ltd. All rights reserved.
Item Type: | Journal Article | ||||||||||||||||||||||||||||
Creators: |
|
||||||||||||||||||||||||||||
URN: | urn:nbn:de:hbz:38-170458 | ||||||||||||||||||||||||||||
DOI: | 10.1016/j.orggeochem.2018.06.006 | ||||||||||||||||||||||||||||
Journal or Publication Title: | Org. Geochem. | ||||||||||||||||||||||||||||
Volume: | 124 | ||||||||||||||||||||||||||||
Page Range: | S. 77 - 88 | ||||||||||||||||||||||||||||
Date: | 2018 | ||||||||||||||||||||||||||||
Publisher: | PERGAMON-ELSEVIER SCIENCE LTD | ||||||||||||||||||||||||||||
Place of Publication: | OXFORD | ||||||||||||||||||||||||||||
ISSN: | 0146-6380 | ||||||||||||||||||||||||||||
Language: | English | ||||||||||||||||||||||||||||
Faculty: | Unspecified | ||||||||||||||||||||||||||||
Divisions: | Unspecified | ||||||||||||||||||||||||||||
Subjects: | no entry | ||||||||||||||||||||||||||||
Uncontrolled Keywords: |
|
||||||||||||||||||||||||||||
Refereed: | Yes | ||||||||||||||||||||||||||||
URI: | http://kups.ub.uni-koeln.de/id/eprint/17045 |
Downloads
Downloads per month over past year
Altmetric
Export
Actions (login required)
![]() |
View Item |