Biospheres

Biospheres, in plural usage, refer to the global sum of all ecosystems on Earth as well as distinct, self-contained life-supporting systems modeled after natural ecosystems. In the broad sense, the biosphere encompasses all living organisms and their interactions with the lithosphere, hydrosphere, and atmosphere, forming a connected web that spans air, land, and sea. Life sustains itself through energy capture—primarily photosynthesis in producers—and flows through food webs, while biogeochemical cycles move nutrients among organisms and physical reservoirs.

Across scales, biospheres vary from local to planetary. Primary production, species diversity, and ecological niches shape the distribution of life. The biosphere regulates climate and atmospheric composition through processes such as carbon sequestration and oxygen production, and it influences soil formation, water quality, and nutrient cycling. It also records geological history in the fossil record.

Historically, scientists such as Vladimir Vernadsky and Eduard Suess described the biosphere as a distinct global system shaped by life itself. The Gaia hypothesis, proposed by James Lovelock, posits strong feedbacks that stabilize Earth's habitability, though it remains debated within the scientific community.

Research on biospheres employs field ecology, geoscience, modeling, and closed ecological systems. Notable attempts to recreate biospheres include closed-environment experiments such as Biosphere 2, which tested long-term containment of air, water, and food webs. Space missions and theoretical designs explore future 'biospheres' for extraterrestrial habitats.

Human activities threaten biosphere integrity through habitat destruction, pollution, invasive species, and climate change. Conservation and sustainable management aim to preserve the capacity of biospheres to support life, maintain ecosystem services, and regulate planetary processes.