My name is Madison Douglas and I am a graduate student at Caltech. I am interested in how landscapes form and how biological, chemical, and physical processes alter landscapes through time through the field of geomorphology. In particular, much of my current research focuses on river systems, which are important links between biogeochemical cycles on the continents and in Earth’s oceans. Rivers also are very important resources for people all around the world, providing food, transportation, and also posing hazards from flooding and erosion. My research develops understanding of the processes that shape rivers and other landscape features so that we can accurately predict the effects of climate change to better engineer and conserve landscapes for societal benefit.
Permafrost landscape mechanics
Ground frozen for at least 2 years (permafrost) underlies much of the modern Arctic. However, permafrost is rapidly thawing as the climate warms, causing significant changes to Arctic landscapes. We currently lack a mechanistic understanding of how the presence of permafrost influences landforms such as hillslopes and rivers, so we cannot accurately predict how they will respond to permafrost thaw. This poses an incredible challenge to the people living in and making policy for permafrost regions, and disproportionately affects Alaska Native communities and other Indigenous residents of the Arctic.
My current work focuses primarily on permafrost riverbank erosion, which already poses a threat to many houses and pipelines in Alaska, and is hypothesized to increase in coming decades. My work includes conducting frozen flume experiments and developing a mechanistic model for permafrost riverbank erosion.
Influence of landscape dynamics on carbon cycling
The thin layer along the Earth’s surface that supports life and drives biogeochemical cycles is frequently called the “critical zone.” Understanding how carbon and the plants and microbial communities that govern carbon fluxes are distributed across landscapes requires collaboration between geomorphologists and other experts in chemistry, ecology, and microbiology. These interdisciplinary studies are particularly important for understanding the fate of currently stored in permafrost that may be converted to greenhouse gases as the Arctic thaws.
I have been lucky to be included in numerous collaborations to characterize organic carbon fluxes in permafrost floodplains. This work includes taking samples from the floodplain and of water and sediment from the river and riverbed to understand where carbon is present, how much, and what classes of organic molecules are present. In addition, I have worked with microbiologists to understand how river migration may influence microbial communities present in floodplains.
River morphology in unvegetated drylands
Plants are known to provide a significant source of strength and cohesion to soils on hillslopes and riverbanks, but they have only been present for less than 20% of Earth’s history. What did landscapes look like before there were land plants?
To address this question, I have conducted multi-year monitoring along the Amargosa River in Death Valley National Park. This reach of the Amargosa lacks plants, and its banks are instead held together by salt crusts and mud. The river also rarely flows, yet it has a surprisingly similar form to other modern rivers with vegetation and perennial water flow.