The potential of biomarkers for reconstructing long-term ecohydrological and microbial community changes in newly discovered Amazonian peatlands

Amariei, Anca Elena (2019) The potential of biomarkers for reconstructing long-term ecohydrological and microbial community changes in newly discovered Amazonian peatlands. MSc(R) thesis, University of Glasgow.

Abstract

The existence of extensive tropical peatlands (i.e. 35,600 ± 2133 km2) was recently confirmed in Amazonia (Lähteenoja et al., 2009 a, b; 2011; Draper et al., 2014). These peatlands appear to be hydrologically intact but are at risk of degradation from anthropogenic impacts and climate change (Roucoux et al., 2017). Furthermore, their discovery represents a new potential source or sink of atmospheric gas budgets and a new component of the CH4 global map that need to be considered in future climate change scenarios.
Our main interests are to test the applicability of biomarkers within these settings, to describe CH4 production in Amazonian peatlands and the changes in CH4 efflux through time, as a function of various environmental parameters, as this information is currently lacking for this area. We focused on surface and core samples from Pastaza-Marañón Foreland Basin, northern Peru with samples associated with three vegetation types, providing thus a wide view over these dynamic ecosystems.
Vegetation and environment related biomarkers (i.e. n-alkanes; hopanes; GDGTs) and proxies are in agreement with changes depicted in pollen records from Quistococha and San Jorge peatland (Roucoux et al., 2013; Kelly et al., 2017). Thus, they can be used to describe shifts in vegetation or environment in the third peatland, Buena Vista. Furthermore, since present day CH4 are not predictable from a water-table depth point of view as, for example, higher effluxes occur during the dry season in black-water seasonally flooded forest (i.e. Bunea Vista; Teh et al., 2017), several biomarker groups were used to further our understanding of processes that lead to these discrepancies. Thus, short chain and monosaturated fatty acids were employed alongside hopanoids and GDGTs, in order to test and understand how the archaea and bacteria, and more specifically, methanogen and methanotroph communities, responded to changes in the ecohydrology. Furthermore, we provide new temperature and pH palaeorecords for each peatland that were previously lacking for these environments and compared them to present-day instrumental measurements in surface samples.
By employing a multi-biomarker approach, we can explore the relationship between environmental parameters via direct and proxy observations of fluctuations in water table depth, changes in vegetation, hydrology and CH4 production potential, gaining a further insight into tropical peatland dynamics and carbon biogeochemical cycles within them. Finally, we encourage higher-resolution biomarker analysis and provide ideas for further research within these peatlands.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Additional Information: This research was possible with the financial support from SAGES and the School of Geographical and Earth Science, University of Glasgow.
• Keywords: biomarkers, peatlands, Amazonia, methane, bacteria, archaea, methanogens, methanotrophs, reconstruction, palaeoenvironment.
• Subjects: Q Science > QD Chemistry; Q Science > QE Geology; Q Science > QR Microbiology
• Colleges/Schools: College of Science and Engineering > School of Geographical and Earth Sciences > Earth Sciences
• Supervisor's Name: Toney, Prof. Jaime
• Date of Award: 2019
• Depositing User: Miss Anca Elena Amariei
• Unique ID: glathesis:2019-40970
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 28 Jan 2019 11:36
• Last Modified: 11 May 2023 14:00
• Thesis DOI: 10.5525/gla.thesis.40970
• URI: https://theses.gla.ac.uk/id/eprint/40970