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How do living organisms create biogenic landforms such as coral reefs and termite mounds?

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continental landform Davis's proposed landscape-development states. The morphology shown is not actually time-indicative. For example, A could be a gully system in soft sediment or a canyon such as the Royal Gorge in Colorado, which is millions of years old. The ridge-ravine topography of B would normally develop under humid conditions, but the river meandering on alluvium indicates a prior or extraneous non-humid aggrading mechanism. The riverine plain of C implies a complex history of planation and aggradation in a current fluvial mode.

Biogenic landforms are topographic features created by the activity of organisms. These structures range from micro-topography to massive landscape features.1

Termite Mounds

Termites construct discrete, concentrated nests using materials such as soil, fine clay particles, or chewed wood. These components are cemented together using saliva or excreta to form durable structures. In tropical regions, certain species build large, prominent mounds that can reach heights of up to 9 meters. These mounds often feature complex internal systems of chambers and galleries, with outer walls composed of hardened soil and internal nurseries made of softer "carton"—a mixture of fecal matter and wood fragments. Some species orient their mounds specifically to regulate internal temperature.2

Coral Reefs

Coral reefs are large-scale biogenic structures formed by the interaction of corals, algae, and bryozoa. These organisms create the framework for organic reefs in tropical marine environments. While the growth of these reefs is influenced by geological processes like plate tectonics and changes in sea level, the physical reef structure itself is a product of biological accumulation and growth.13