Short answers, pulled from the story.
Ecology defines a marsh as a wetland dominated by herbaceous plants rather than woody ones. Grasses, rushes, and reeds take root in the shallow mud here while trees remain small shrubs known as carr.
Plants survive this environment through specialized structures called aerenchyma which run inside stems to move air down to roots buried in oxygen-poor mud. Rhizomes store energy underground for reproduction when conditions shift.
Three main categories define global distribution based on salinity and position including salt marshes, freshwater tidal marshes, and freshwater marshes. Each type adapts to specific environmental pressures found around the globe.
Marshes filter pollutants and sediment from flowing water before it reaches oceans while reducing flooding magnitude during storm events. Their influence on climate resilience remains outsized relative to their size because coastal areas rely on them to absorb extreme weather tides.
Some regions have lost 90 percent of their original wetland cover as urban sprawl fills former marshes to build cities and roads. Farmers drain land to create fields for agriculture while pollution from expanding cities threatens freshwater tidal marshes nearby.