Bathymetric: Studies of ocean floors.
Diagenesis: The process by which sediment turns into rock.
Hadal zone: The deepest region of the ocean lying within oceanic trenches. The hadal zone is found from a depth of 6,000 to 11,000 m.
Hydrolysis: Cleavage of chemical bonds by the addition of water.
Lysis: The breaking down of the membrane of a cell.
Macrofauna: Small organisms which are retained on a 0.5 mm sieve. Studies in the deep sea define macrofauna as animals retained on a 0.3 mm sieve to account for the small size of many of the taxa.
Meiofauna: Small benthic invertebrates that live in both marine and fresh water environments. They can pass unharmed through a 0.5 – 1 mm mesh but will be retained by a 30–45 μm mesh. Smaller than macrofauna.
Microheterogeneity: Variation in the chemical structure of a substance that does not produce a major change in its properties.
Oligotrophic: An oligotrophic environment is an environment that offers little to sustain life.
Piezophilic: High pressure loving.
Photic zone: Surface layer of the ocean that receives sunlight.
Phylogenetic: The development or evolution of a particular group of organisms.
Phytodetrital: Relating to, or composed of phytodetritus (marine detritus, of plant origin, that slowly sinks to the depths and is the food source for abyssal benthic communities).