Compound-specific stable carbon and hydrogen isotope analyses of vegetation and precipitation change in a Belizean pine savanna

Keywords: Lake sediments, savannas, hydrogen isotopes, carbon isotopes, Belize
Session Type: Virtual Paper Abstract
Day: Tuesday
Session Start / End Time: 3/1/2022 03:40 PM (Eastern Time (US & Canada)) - 3/1/2022 05:00 PM (Eastern Time (US & Canada))
Room: Virtual 17

Abstract

Studying lake sediment cores from neotropical savannas can shed light on the environmental history of savannas over the Holocene, including the influences of fire, climate, and human activities. Analyzing the compound-specific carbon and hydrogen isotope ratios of organic compounds in lake sediments complements studies of pollen and charcoal by allowing paleolimnologists to disentangle the effects of anthropogenic disturbance and climate on vegetation and fire regimes. Pine Pond is located in a tropical pine savanna within the Deep River Forest Reserve of southern Belize. Previous analyses of two cores spanning ca. 1300 and 4900 years reconstructed fire from high-resolution macroscopic charcoal, vegetation from pollen grains, and vegetation and carbon sources from bulk stable carbon and nitrogen isotopes. This study builds upon prior work by analyzing compound-specific carbon and hydrogen isotope ratios from 42 levels in the Pine Pond sediment profiles. The new vegetation and precipitation records are compared to existing records of vegetation and fire at Pine Pond, other lake sediment records from the region, and speleothem records, with a focus on periods of drought such as the Little Ice Age (AD 1450–1850) and Terminal Classic Drought (AD 750–1100). Comparing our precipitation record with other datasets from the region allows us to determine if shifts in fire documented by charcoal analysis were driven by climate, human activity, or possibly both.