Tropical Peatlands in West Kalimantan: Formation, Carbon, and Late Pleistocene-Holocene History
| dc.contributor.advisor | Gavin, Daniel | |
| dc.contributor.author | Ruwaimana, Monika | |
| dc.date.accessioned | 2024-01-09T22:45:01Z | |
| dc.date.available | 2024-01-09T22:45:01Z | |
| dc.date.issued | 2024-01-09 | |
| dc.description.abstract | Peatlands hold an important function in the global carbon cycle. Despite only covering 3–4% of the terrestrial landscape, peatlands disproportionately store 30–40% of the Earth’s soil carbon. Temperate and boreal peatlands are mostly well-studied, while tropical peatland is relatively understudied. In the past decades, tropical peatland especially in Southeast Asia has become a center of attention due to frequent disastrous fires. However, its basic properties such as depth, extent, carbon storage, formation, and its potential as an environmental archive are rarely studied. Thus, in this dissertation, I explored a tropical peatland in West Kalimantan, Indonesia, and conducted a stratigraphic study on several peat cores to reveal its ecological history. We collected 32 peat cores from two main study areas, coastal peatland and inland peatland. We conducted radiocarbon dating and analyses of bulk density, loss-in-ignition, organic geochemistry (C%, N%, δ13C, and δ15N), charcoal counts, and pollen identification. We found that the coastal peatland (6m depth) is thinner than the inland peat (15m), and younger (4,500yr vs 50,000yr). The age and thickness of our inland peat site put it as the deepest and oldest extant peatland in the world, and subsequently as the most carbon-dense ecosystem. In their genesis, coastal peatland has a simple linear age-depth relationship, showing stable accumulation of carbon. In contrast, inland peat shows a complex history, where we observed age reversals and hiatuses, likely caused by climate variability from the Last Glacial Maximum (LGM) to the Holocene. Our study is the first that utilized multiple cores to create continuous vertical age and geochemical profiles, which revealed an age reversal that was likely caused by flood events. The charcoal record reveals a continuous presence of low severity fire, with increasing late Holocene fire frequency presumably due to increasing anthropogenic influence. Finally, we conducted pollen analysis and created a pollen atlas, which will be used for future palynological work to explore the vegetation change throughout time. This research highlights not only modern, but also the historical and prehistorical importance of tropical peatland as a dynamic long term carbon storage that withstood the glacial-interglacial climate transition but is currently threatened by deforestation and land-use change. This dissertation includes previously published and unpublished coauthored material. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/29156 | |
| dc.language.iso | en_US | |
| dc.publisher | University of Oregon | |
| dc.rights | All Rights Reserved. | |
| dc.subject | Carbon dynamic | en_US |
| dc.subject | Fire reconstruction | en_US |
| dc.subject | Peat fire | en_US |
| dc.subject | Peatland | en_US |
| dc.subject | Stratigraphic study | en_US |
| dc.subject | Tropical peatland | en_US |
| dc.title | Tropical Peatlands in West Kalimantan: Formation, Carbon, and Late Pleistocene-Holocene History | |
| dc.type | Electronic Thesis or Dissertation | |
| thesis.degree.discipline | Department of Biology | |
| thesis.degree.grantor | University of Oregon | |
| thesis.degree.level | doctoral | |
| thesis.degree.name | Ph.D. |
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