A VERY HOT SPOT: Characterizing Soil Organic Carbon in the Hawaiian Chrono and Climosequence

Abstract

Soil in Hawaii has been extensively studied to better understand the properties that make it effective in capturing and storing organic carbon for long periods of time. In particular, the age and rainfall gradients found naturally occurring on the Hawaiian Islands make it salient for soil research, thus far yielding insights into how mineral composition, age, and vegetation influence the abundance of soil carbon. However, the character of organic carbon along these gradients has remained virtually unknown, holding space for this study to explore how the soil profile changes with respect to the functional groups present in organic carbon molecules. This study focuses first on how previously identified properties of soil important for carbon sequestration (i.e. mineral content) independently influence sorption and collection of organic matter, and then explore how organic carbon molecule change by experimenting on whole soil samples, via experimentation on both the solid and mobile phases of the molecules. In doing so, this determination of the type of carbon present in soil and how it changes as a function of age and climate will further the understanding of soil carbon dynamics in carbon turnover and sequestration.