Biosphere

Abiotic

Non-living components of an ecosystem, such as water, air, temperature, and minerals.

Anoxic

An environment devoid of free oxygen.

Atmosphere

The layer of gases surrounding the Earth.

Autotroph

An organism that can produce its own food from inorganic sources, such as sunlight or chemical energy.

Biomineralization

The process by which living organisms produce minerals, often to harden body structures (e.g., shells, bones).

Biosphere

The sum of all living organisms on Earth and the environments in which they live.

Biota

The living organisms of a particular region or ecosystem.

Calcite Compensation Depth (CCD)

The depth in the ocean below which the rate of calcium carbonate dissolution exceeds the rate of its supply, preventing the accumulation of carbonate sediments.

Carbon Cycle

The biogeochemical cycle that describes the movement of carbon through Earth's atmosphere, oceans, biosphere, and geosphere.

Carbon Fixation

The process by which autotrophs convert inorganic carbon dioxide (CO2) into organic compounds, such as sugars.

Chemoautotroph

An organism that obtains energy from the oxidation of inorganic compounds.

Chemotrophy

The process of obtaining energy from chemical reactions.

Cryosphere

The portion of Earth's system that includes all frozen water, such as glaciers, ice caps, and permafrost.

Decomposers

Organisms, primarily bacteria and fungi, that break down dead organic matter, releasing nutrients back into the ecosystem.

Denitrification

The microbial process by which nitrate (NO3-) is converted back to nitrogen gas (N2), releasing it into the atmosphere.

Eukaryote

An organism whose cells contain a membrane-bound nucleus and other organelles.

Extremophile

An organism that thrives in extreme environments, such as those with high temperatures, acidity, or salinity.

Feedback Mechanism

A process in which the output of a system affects its input, leading to either amplification (positive feedback) or dampening (negative feedback) of the original change.

Geobiology

The study of the interactions between Earth's physical, chemical, and biological processes.

Geosphere

The solid, non-living parts of the Earth, including rocks, minerals, and soil.

Gross Primary Production (GPP)

The total amount of organic matter produced by primary producers through photosynthesis.

Heterotroph

An organism that obtains its food by consuming other organisms.

Hydrosphere

The portion of Earth that includes all forms of water, such as oceans, lakes, rivers, and groundwater.

Limiting Nutrient

A nutrient that is in short supply relative to the needs of organisms, thereby restricting their growth and reproduction.

LUCA (Last Universal Common Ancestor)

The hypothetical most recent common ancestor of all extant life forms on Earth.

Macromolecule

A large molecule, typically composed of many repeating subunits, such as proteins, carbohydrates, and nucleic acids.

Metabolism

The sum of all chemical processes that occur within a living organism to maintain life.

Net Primary Production (NPP)

The amount of organic matter produced by primary producers that remains after accounting for their own respiration.

Nitrification

The microbial process by which ammonia (NH3) is converted to nitrite (NO2-) and then nitrate (NO3-).

Nitrogen Cycle

The biogeochemical cycle that describes the movement of nitrogen through Earth's atmosphere, oceans, and biosphere.

Nutrient

A substance that provides nourishment essential for the growth and maintenance of life.

Oxidation

A chemical reaction involving the loss of electrons.

Oxygenic

Pertaining to a process that produces oxygen as a byproduct, such as oxygenic photosynthesis.

Photoautotroph

An organism that obtains energy from sunlight through photosynthesis.

Photoferrotrophy

A form of anoxygenic phototrophy in which ferrous iron (Fe2+) is used as an electron donor.

Phototrophy

The process of obtaining energy from sunlight.

Primary Production

The synthesis of organic matter from inorganic sources by autotrophs.

Prokaryote

A single-celled organism that lacks a membrane-bound nucleus and other membrane-bound organelles.

Reduction

A chemical reaction involving the gain of electrons.

Remineralization

The breakdown of organic matter into inorganic nutrients.

Residence Time

The average length of time a substance remains in a particular reservoir.

Respiration

The process by which organisms break down organic compounds to release energy.

Siderophore

A high-affinity molecule produced by microorganisms that binds to ferric iron (Fe3+), making it soluble and bioavailable.

Sink

A reservoir that absorbs a substance from another part of a system.

Source

A reservoir that releases a substance into another part of a system.

Stromatolite

Layered mounds of sedimentary rock formed by microbial mats, primarily cyanobacteria.

Taxonomic Rank

A hierarchical level in the classification of organisms, such as kingdom, phylum, class, order, family, genus, and species.

Weathering

The breakdown of rocks and minerals at Earth's surface by physical and chemical processes.