• amphipod: small, flat-bodied, shrimp-like crustacean
• aquifer: a source of groundwater for wells and springs made up of a permeable layer of rock or sediment
• artesian well: a water well drilled into a confined aquifer whose pressure causes the water to flow to the surface without pumping, because the well acts as a point of release

B

• biodiversity: the variety, complexity, and abundance of species in an ecosystem
• biofilm: a thin, slimy film of bacteria that adheres to a surface

C

• chironomid: formally, chironomidae; tiny, non-biting mosquito-like flies
• confined aquifer: a body of underground water in between two layers of impermeable rock, causing the water to be under pressure
• copepod: a type of small crustacean found in most freshwater environments, usually having six pairs of limbs on the thorax
• crustacean: animal that has a hard shell and segmented body, such as a lobster

D

• detrivore: obtains much of its nutrients from detritus

E

• endangered status: the classification provided to an animal or plant in danger of extinction within the foreseeable future throughout all or a significant portion of its range

F

• filter feeder: feeds by removing food from the water, such as a sponge

G

• Glen Rose formation: the uppermost, thickest and most extensively exposed formation of the Trinity Group which is exposed over a large area in Central Texas
• groundwater: freshwater that is found below the surface of the earth
• gut abundance:

H

• hydrologic cycle: natural pathway water follows as it changes between liquid, solid, and gaseous states in the atmosphere, ocean, and the Earth's surface; also called the water cycle
• hydrostratigraphic zone: an area of rock layers which effect the flow of groundwater

I

• invertebrate: animal lacking a backbone

K

• karst: landform type characterized by sinks, underground streams, and caverns and an absence of surface streams and lakes

L

• larva: the immature stage in the life cycle of an invertebrate, amphibian, or fish before metamorphosis into its adult form
• limestone: rock that consists mainly of calcium carbonate and is chiefly formed by accumulation of organic remains

N

• nutrient cycling: the transfer of nutrients between the organisms in a food web

O

• obligate predator: a predator who is restricted to one species of prey
• opportunistic predator: a predator who will prey on almost anything that crosses their path
• organic detritus: accumulated decaying organic material
• ostrocod: seed shrimp: tiny marine and freshwater crustaceans with a shrimp-like body enclosed in a bivalve shell

P

• permeable: describes a substance that allows liquids or gases to pass through
• porosity: level to which something allows water to pass through it

S

• saturated zone: the area below the water table where all open spaces are filled with water
• scavenger: feeds on dead and dying organisms

T

• tricorythode: a genus of mayflies with a freshwater nymph stage
• trophic: of, relating to, or characterized by a specified kind of nutrition

U

• unconfined aquifer: an aquifer containing water that is not under pressure, this occurs in the saturated zone or water table
• unsaturated zone: the area above the water table where soil pores are not fully saturated, although some water may be present

W

• water table: the level below the earth's surface at which the ground becomes saturated with water
• well: a bored, drilled, or driven shaft or a dug hole whose purpose is to reach underground water or oil supplies

(Source of some definitions: www.edwardsaquifer.net)