Leaf wax n-alkane distributions in arid zone South African flora: Environmental controls, chemotaxonomy and palaeoecological implications

Carr, Andrew S.; Boom, Arnoud; Grimes, Hannah L.; Chase, Brian M.; Meadows, Michael E.; Harris, Angela

doi:10.1016/j.orggeochem.2013.12.004

Cited by 119 publications

(80 citation statements)

References 59 publications

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“…2). In the case of Gouritz River catchment samples and GeoB18308-1 down-core samples, plant waxes indicate a dominant Karoo vegetation signature according to Carr et al (2014) and Hermann et al (2016) (Fig. 2).…”

Section: Sediment Provenance Indicatorsmentioning

confidence: 90%

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Southern Hemisphere anticyclonic circulation drives oceanic and climatic conditions in late Holocene southernmost Africa

et al. 2017

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Abstract. Due to the high sensitivity of southern Africa to climate change, a reliable understanding of its hydrological system is crucial. Recent studies of the regional climatic system have revealed a highly complex interplay of forcing factors on precipitation regimes. This includes the influence of the tropical easterlies, the strength of the southern hemispheric westerlies as well as sea surface temperatures along the coast of the subcontinent. However, very few marine records have been available in order to study the coupling of marine and atmospheric circulation systems. Here we present results from a marine sediment core, recovered in shallow waters off the Gouritz River mouth on the south coast of South Africa. Core GeoB18308-1 allows a closer view of the last ∼ 4 kyr. Climate sensitive organic proxies, like the distribution and isotopic composition of plant-wax lipids as well as indicators for sea surface temperatures and soil input, give information on oceanographic and hydrologic changes during the recorded time period. Moreover, the micropaleontology, mineralogical and elemental composition of the sediments reflect the variability of the terrigenous input to the core site. The combination of down-core sediment signatures and a catchment-wide provenance study indicate that the Little Ice Age (∼ 300-650 cal yr BP) was characterized by climatic conditions favorable to torrential flood events. The Medieval Climate Anomaly (∼ 950-650 cal yr BP) is expressed by lower sea surface temperatures in the Mossel Bay area and humid conditions in the Gouritz River catchment.These new results suggest that the coincidence of humid conditions and cooler sea surface temperatures along the south coast of South Africa resulted from a strengthened and more southerly anticyclonic circulation. Most probably, the transport of moisture from the Indian Ocean by strong subtropical easterlies was coupled with Agulhas Bank upwelling pulses, which were initiated by an increase in Agulhas Current strength.

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Section: Sediment Provenance Indicatorsmentioning

confidence: 90%

“…In this study, the n-C 31 alkane is the most abundant n-alkane of the plant waxes and thus used as an indicator of vegetation type in addition to Norm31 ratios. Carr et al (2014) show vegetation-specific distributions of n-alkane homologues within the arid-zone South African flora (Fig. 2).…”

Section: Sediment Provenance Indicatorsmentioning

confidence: 99%

Southern Hemisphere anticyclonic circulation drives oceanic and climatic conditions in late Holocene southernmost Africa

et al. 2017

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“…and a commensurate reduction in the abundance of these riparian pollen types, more subtle 73 adjustments in wetland and terrestrial vegetation communities were inferred we also present new data pertaining to the biomarker and stable isotope fingerprints of modern 116 plant-derived organic matter from the area, building on several recent studies ; 117 Carr et al 2014). 118…”

Section: Introductionmentioning

confidence: 88%

“…1). These relate to terrestrial soils adjacent to Verlorenvlei, specifically sites SV3 and 150 SV5 described in Carr et al (2013Carr et al ( , 2014, along with samples from a modern salt marsh, 24 km north 151 of Velddrif, south of Verlorenvlei ( Eight bulk sediment samples from KFN2010 were used to construct a radiocarbon 156 chronology. AMS analyses were carried out at the University of Waikato radiocarbon datingSHCal13 (Hogg et al 2013) using CALIB 7.0 (Stuiver and Reimer 1993).…”

Section: Sampling Chronology and Analyses 144mentioning

confidence: 99%

Holocene sea level and environmental change on the west coast of South Africa: evidence from plant biomarkers, stable isotopes and pollen

et al. 2015

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“…In tropical ecosystems, several studies observed C 29 as the most dominant n-alkane homologue in C 3 rainforest trees, whereas C 4 grasses and herbs mainly produced C 33 as the most abundant homologue (Feakins et al, 2016;Vogts et al, 2009;Garcin et al, 2014). For the more arid area of South Africa, a dominance of C 31 and C 33 n-alkanes is reported for succulent plants and regional soils (Carr et al, 2014). Altogether, most regional studies show a good chemotaxonomic discrimination power of n-alkane patterns, demonstrating their great potential to reconstruct paleovegetation when used in sedimentary archives at least in these regions.…”

Section: N-alkane Patterns In Modern Plants and Topsoilsmentioning

confidence: 99%

Leaf wax <i>n</i>-alkanes in modern plants and topsoils from eastern Georgia (Caucasus) – implications for reconstructing regional paleovegetation

et al. 2018

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Abstract. Long-chain n-alkanes originate from leaf waxes of higher terrestrial plants, they are relatively resistant against physical and chemical degradation and are preserved in sediment archives for at least millennial timescales. Since their homologue patterns discriminate between vegetation forms, they were increasingly used for paleovegetation reconstructions during the last years. However, before any robust interpretation of the long-chain n-alkane patterns in sediment archives, reference samples from modern vegetation and topsoil material should be investigated at a regional scale. Apart from some temperate and tropical regions, such systematic regional studies on modern plant and topsoil material are still largely lacking.To test the potential of leaf wax-derived n-alkane patterns for paleoenvironmental studies in the semi-humid to semiarid central southern Caucasus region, we investigated the influence of different vegetation forms on the leaf wax n-alkane signal in modern plants and topsoil material (0-5 cm) from eastern Georgia. We sampled (i) sites with grassland/herbs that included steppe, cultivated grassland and meadows, and (ii) sites that are dominated by deciduous hornbeam forests.The results show that long-chain n-alkanes originate from leaf waxes of higher terrestrial plants and that their homologue pattern allow to discriminate between different vegetation forms: n-Alkanes derived from sites with grassland/herbs are mainly dominated by C 31 , while n-alkanes derived from sites with deciduous trees/shrubs show high abundances of C 29 . Thus, long-chain n-alkanes have a great potential when used for regional paleovegetation reconstructions. Moreover, the n-alkane distributions of the topsoils do not show correlations with mean annual temperatures and precipitation along the investigated transect. As degradation of organic matter can affect the leaf wax n-alkane distribution, we further present an updated end-member model that includes our results, accounts for degradation effects and enables semi-quantitative reconstructions of past vegetation changes in the central southern Caucasus region.

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Leaf wax n-alkane distributions in arid zone South African flora: Environmental controls, chemotaxonomy and palaeoecological implications

Cited by 119 publications

References 59 publications

Southern Hemisphere anticyclonic circulation drives oceanic and climatic conditions in late Holocene southernmost Africa

Southern Hemisphere anticyclonic circulation drives oceanic and climatic conditions in late Holocene southernmost Africa

Holocene sea level and environmental change on the west coast of South Africa: evidence from plant biomarkers, stable isotopes and pollen

Leaf wax <i>n</i>-alkanes in modern plants and topsoils from eastern Georgia (Caucasus) – implications for reconstructing regional paleovegetation

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Leaf wax n-alkane distributions in arid zone South African flora: Environmental controls, chemotaxonomy and palaeoecological implications

Cited by 119 publications

References 59 publications

Southern Hemisphere anticyclonic circulation drives oceanic and climatic conditions in late Holocene southernmost Africa

Southern Hemisphere anticyclonic circulation drives oceanic and climatic conditions in late Holocene southernmost Africa

Holocene sea level and environmental change on the west coast of South Africa: evidence from plant biomarkers, stable isotopes and pollen

Leaf wax &lt;i&gt;n&lt;/i&gt;-alkanes in modern plants and topsoils from eastern Georgia (Caucasus) – implications for reconstructing regional paleovegetation

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Leaf wax <i>n</i>-alkanes in modern plants and topsoils from eastern Georgia (Caucasus) – implications for reconstructing regional paleovegetation