Permafrost in a Warmer World

Background

Northern high latitudes are expected to get warmer and wetter in the future with rates of warming twice that of the global average, leading to increased initiation and expansion of permafrost thaw. When ice-rich permafrost thaws, the land subsides and saturates, transitioning permafrost forest and tundra into lakes and wetlands. As this transition occurs, the energy budget, water budget, and carbon budget of the landscape fundamentally change, which can, in turn, facilitate greater rates of thaw and landscape transition.

The transition of permafrost to wetland, which is associated with thaw of ice-rich permafrost and land subsidence (termed thermokarst), has a net warming impact on the climate over decade to century timescales due to the rapid release of below-ground carbon stores and emission of methane generated within anaerobic wetland soils.

Overview

My Ph.D. research in the Hydro-biogeochemical Research Group at the University of Washington (lab website) aims to give a more complete understanding of the environmental controls that influence rates of permafrost thaw and resultant wetland carbon release under both current and future climate conditions. We are using data collected during my fieldwork in Alaska, as well as historical data from diverse sites across the northern hemisphere, to meet these goals.

My fieldwork includes a slew of hydrologic (hydraulic head, precipitation, air temperature, solar radiation, snow disappearance date, ect.), biogeochemical (porewater chemistry, carbon flux, plant metrics etc.), and spatial (surface topography, depth to permafrost, kinematic GPS surveys, ect.) data. These data are paired with soil temperature data from the surface into permafrost. I have two sites in Alaska. The first site, located in Interior Alaska, will allow for measurements under current sub-arctic climate conditions, while the second site, located on the warmer and wetter Kenai Peninsula, will allow for measurements under projected future sub-arctic climate conditions. The fieldwork portion of the study will last three years, with one season already completed.

There is particular emphasis on the ability of rain to affect rates of permafrost thaw and biogeochemical processing in wetlands.

Splash-Cup Plant Dispersal

Splash-cup plants disperse their seeds by exploiting the kinetic energy of raindrops. When raindrops impact the splash-cup, seeds are projected up to 1 m away from the parent plant. This study focused on the conical splash-cups of the genera Chrysosplenium (golden-saxifrage) and Mazus. Our study used a 40° cone angle with the addition of seeds of varying characteristics to determine the impact that seeds of varying characteristics have on the dispersal distance and splash dynamics of splash-cup plants. We 3D-printed models of the conical fruit bodies of the splash-cups using UV curable resin and used high-speed video to find splash characteristics such as angle and velocity of seeds as they exit the seed cup. Splash characteristics and dispersal distances of seeds with differing characteristics such as size, shape, texture, density, and hydrophobicity were compared to one another, as well as to the case of having no seeds present. We found that the presence of seeds dramatically decreased dispersal distance and altered splash characteristics. In addition, our data showed that seeds with different characteristics yielded splashes with differing dispersal distance and splash characteristics. Splash characteristics of glass beads with differing contact angles were compared to one another, and yielded some difference in dispersal distance.

Namibian Cultural Botany

I was granted the opportunity to conduct botany research with Professor Rachel DeMotts in the Zambezi region of Namibia. The goal of this research was to eternalize ancient ecological knowledge of the traditional uses of local plants before it was lost. This research involved botany walks in the Namibian bush with local elders, recording and participating in traditional basket weaving techniques, the ultimate publication of a plant dictionary in four languages that was given to the schools, lodges, and conservancies of the region, and a talk in front of nearly three hundred of the University of Puget Sound’s largest donors.