Plants steer the way rivers meander across the landscape

Amazing stuff!

"New research confirms that the rise of land-based plant life changed the way rivers move, but not in the way geologists have thought, and taught, for decades.

The new study ... has discovered a new way in which floodplain vegetation – the plant life which grows in flat land next to a river – controls river dynamics.

Today, rivers on Earth come in 2 types: braided and meandering. ..."

"In brief

• New Stanford research redefines river evolution, suggesting meandering patterns were prevalent in Earth's landscapes earlier than thought.
• The study reveals unvegetated rivers can mimic braided rivers, altering our understanding of carbon reservoirs and ecological history.
• The findings provide important insights into Earth’s past and may impact future climate models.

..."

From the abstract:

"A primary axiom in geoscience is that the evolution of plants drove global changes in river dynamics. Notably, the apparent sinuosity of rivers, derived from the variance of sediment accretion direction measured in rocks, dramatically increased when land plants evolved, ca. 425 Ma. This led to the hypothesis that the rise of vegetation triggered river meandering. Recent studies of barren, meandering rivers challenge this notion, but the Paleozoic shift in the geometry of river deposits remains unexplained.

Here, we suggest that it occurred because vegetation changes how river bends move through space. Using satellite images to monitor river migration, we find that bank vegetation alters the orientation of point bar accretion, resulting in a 62% increase in the inferred variance of flow direction. These results explain why meandering rivers have been under-recognized in pre-vegetation stratigraphy."

Plants steer the way rivers meander across the landscape

The rise of plant life reshaped river behavior, study finds (original news release) "Research suggests that unvegetated meandering rivers were more common in the first 90 percent of Earth’s history than previously thought, challenging previous assumptions and providing new insights into the early ecology and climate of our planet."

Vegetation changes the trajectory of river bends (no public access)

A view of seasonal flow in Shoshone Creek – an unvegetated meandering stream in Nevada.