Biogenic

Biogenic is an adjective used to describe substances, structures, or processes that originate from living organisms. It contrasts with abiogenic or abiotic sources, which arise without biological involvement. The term is employed across biology, ecology, geology, geochemistry, and environmental science to tag features attributed to biological activity or origin.

Biogenic minerals and sediments: A large portion of Earth's mineral formations are the products of organisms. Examples include calcium carbonate structures such as shells, corals, and foraminifera, which build biogenic carbonate rocks like limestone. Biogenic silica from diatoms and radiolarians forms extensive sediment layers. Biogenic apatite is found in bones and teeth. In sediments, the distribution and composition can reflect past or present biological activity.

Biogenic gases and carbon cycling: Microorganisms generate gases such as methane and carbon dioxide through metabolic processes. These biogenic gases influence atmospheric composition and climate. Nitrogen and sulfur cycles also involve biogenic transformations, including nitrification, denitrification, and sulfate reduction.

Biogenic substances as biosignatures: Certain organic molecules, isotopic ratios, and microfossil assemblages serve as biomarkers indicating past or present life. In geology and astrobiology, biogenic indicators help distinguish biological from abiotic origins.

Applications and relevance: Biogenic processes are central to ecosystem function, nutrient recycling, and energy flow. In geology, recognizing biogenic inputs helps interpret rock records, reconstruct past environments, and assess fossil-fuel origins. The term remains a general descriptor rather than a mechanism, covering any feature attributable to living systems.