antibiotic: A germ-killing substance, usually prescribed as a medicine (or sometimes as a feed additive to promote the growth of livestock). It does not work against viruses.
bacteria: (singular: bacterium) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms (such as plants and animals). Bacteria are one of the three domains of life on Earth.
chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom.
climate: The weather conditions that typically exist in one area, in general, or over a long period.
climate change: Long-term, significant change in the climate of Earth. It can happen naturally or in response to human activities, including the burning of fossil fuels and clearing of forests.
coral: Marine animals that often produce a hard and stony exoskeleton and tend to live on reefs (the exoskeletons of dead ancestor corals).
crystal: (adj. crystalline) A solid consisting of a symmetrical, ordered, three-dimensional arrangement of atoms or molecules. It’s the organized structure taken by most minerals.
ecosystem: A group of interacting living organisms — including microorganisms, plants and animals — and their physical environment within a particular climate. Examples include tropical reefs, rainforests, alpine meadows and polar tundra. The term can also be applied to elements that make up some an artificial environment, such as a company, classroom or the internet.
egg: A reproductive cell that contains half of the genetic information necessary to form a complete organism.
extinction: The permanent loss of a species, family or larger group of organisms.
larvae: (s. larva) Immature insects that have a distinctly different form (body shape) than when they are adults. For instance, caterpillars are larval butterflies and maggots are larval flies. (Sometimes this term also is used to describe such a stage in the development of fish, frogs, corals and other animals.)
liquid nitrogen: A colorless, odorless, nonflammable refrigerant used in research to keep things amazingly cold or frozen. It can chill things down and hold them at temperatures as low as -196° Celsius (-320.8° Fahrenheit).
marine: Having to do with the ocean world or environment.
mature: (adj.) Connoting an adult individual or full-grown and fully developed (non-juvenile) form of something. (verb) To develop toward — or into — a more complex and full-grown form of something, be it a living thing, a technology or an idea.
organism: Any living thing, from elephants and plants to bacteria and other types of single-celled life.
reef: A ridge of rock, coral or sand. It rises up from the seafloor and may come to just above or just under the water’s surface.
risk: The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)
sea: An ocean (or region that is part of an ocean). Unlike lakes and streams, seawater — or ocean water — is salty.
spawn: To quickly cause something to come into being. (in biology) To release or fertilize eggs in an aquatic environment.
tissue: Made of cells, it is any of the distinct types of materials that make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues.