Chesapeake and Coastal Bay Life Glossary


Adhesive - Sticky.

Alkaline - Acting like a base; having a pH of more than 7.

Anaerobic - Without oxygen.

Antapical - Pertaining to the posterior or rear of a dinoflagellate (the hypotheca).

Anterior - The front end of the body or structure.

Areolae - Perforations through the valve (cell) wall of a diatom.

Arthropod - A large taxonomic group of animals with jointed legs; includes insects and crustaceans among other animals.

Barbels - A fleshy, tactile icicle-shaped projection, usually near the lips, chin or nose of a fish.

Benthic - Living in or on the bottom of a body of water.

Benthos ("Bottom Dwellers") - Those organisms that live in or on the bottom of a body of water. The benthos is one of three divisions of aquatic life; the others are the nekton ("swimmers") and the plankton ("drifters").

Bivalves - An animal (as a clam or oyster) with a 2-valved shell.

Brackish - Somewhat salty, as in brackish water.

Brood - To incubate and protect eggs until hatching.

Budding - Pinching off of a small part of the parent to form a new organism; a form of asexual reproduction.

Buoyant - Floats easily, and is less dense than water.

Cardinal teeth - Ridges or grooves that help hold the shells of a bivalve in alignment.

Carapace - The protective hard shell-like shield that covers the back of an animal (such as a crab or a turtle).

Carnivore - An animal that eats other animals.

Caudal fin - Tail fin.

Caudal peduncle - Trunk of the tail fin.

Chloroplast - The portion of a cell that contains the photosynthetic pigment chlorophyll.

Chlorophyll a- A photosynthetic pigment that serves as a surrogate measure for abundance of algae.

Colloquial - Regional slang.

Compound leaves - A plant with several leaves or leaflets coming from a common leaf stalk is said to have a compound leaf structure.

Coriolis Effect - The tendency for any moving body on or above the earth's surface, such as a water current, to drift sideways from its course because of the earth's rotation. The Coriolis Effect occurs because the speed of a point on the earth's surface is greater for point near the equator than for a point near the poles. In the Northern Hemisphere the deflection is to the right of the motion.  Thus saltwater moving north up the Chesapeake Bay is deflected to the east, and freshwater moving south down the Bay is deflected to the west, resulting in higher salinities on the Eastern Shore of Maryland than on the Western Shore at the same latitude.

Ctenophore - A comb jelly, a transparent gelatinous planktonic animal. Comb jellies have rows of cilia that look like combs. Unlike sea nettles and other jellyfish, comb jellies do not have stinging cells.

Cuticle - Non-cellular outer portion of the integument (skin).

Cyanobacteria - Formerly called blue-green algae or cyanophytes.

Demersal - Species that live near the bottom of the water body.

Detritivore - An organism that consumes detritus.

Detritus - Litter formed from fragments of dead material in aquatic environments.

Dorsal - Located near or on the back surface of an animal.

Dorsal Fin - The fin/fins of the midline of the back of the fish or marine mammal.

Dorsoventrally compressed - Elongated and/or flattened; length much greater than height.

Dorsum - Top region of the fish.

Echolocate- Locate and discriminate among objects by producing sounds and then hearing the echo.

Emergent Vegetation - Plants that are rooted in the water but with most of the plant growing above the surface of the water, such as cattails and wild rice.

Epicone - Anterior (front) part of a dinoflagellate, above the horizontal flagella.

Epitheca - Same as epicone; anterior (front) part of a dinoflagellate, above the horizontal flagella.

Estuary - A semi-enclosed body of water where saltwater mixes with fresh water such as the Chesapeake Bay.

Exoskeleton - The external supportive covering of insects, crustaceans and other arthropods.

Euryhaline - An organism that is capable of living in a wide range of salinity concentrations.

Fertilized/Fertilization - The union of a female gamete (egg) with a male gamete (sperm).

Filamentous - Very thin, threadlike.

Flagellum (plural: flagella) - A long whip-like extension that many single-celled aquatic organisms use for locomotion.

Flank - Side.

Food Webs - Interacting food chains in an ecological community.

Genitalia - The internal or external organs of the reproductive system.

Genus (plural: Genera) - A taxonomic group below family and above species.

Girdle - Side view of a diatom; the region between two valves.

Gravid - The state of being pregnant.

Habitats - The places where plants and animals live.

Hemimetabolous - Having/undergoing incomplete metamorphosis, showing a gradual change from molt to molt, changing gradually from the nymph to the adult.

Herbivore - An organism that consumes plant material.

Hermaphroditic - An animal or plant having both male and female reproductive organs.

Heterotroph - An organism that depends on consumption of other organisms and organic material for energy.

Holometabolous - Having/undergoing complete metamorphosis during development; the stages include egg, larva, pupa and adult.

Hypotheca - Posterior (rear) part of a dinoflagellate, area below the horizontal flagella.

Indicator species - A species whose status provides information on the overall health of the ecosystem and of other species in that ecosystem. Indicator species reflect the quality and changes in environmental conditions as well as aspects of community composition.

Invertebrate - Animal without a spine.

Intertidal - The portion of the shoreline that is underwater during an average high tide and exposed at an average low tide.

Iridescence - Colors of the rainbow in shifting hues and patterns.

Labium - The lower lip of an arthropod.

Labrum - The upper lip of an arthropod.

Larva (plural is larvae) - The immature, wingless form of many insects that hatches from the egg. The larva then transforms into a pupa, and then metamorphoses into the adult form.

Lancoelate leaves - Leaves having a rounded base tapering towards a pointed tip.

Mandibles - Paired, pincer-like hardened mouthparts (jaws) in arthropods, which are used to grasp, tear, and push food into the mouth.

Margin of opercle - Edge of the operculum or gill covering.

Marsupium - Structures in invertebrates for enclosing or carrying eggs or young.

Mature - An individual that has reached the age for reproduction.

Mesohaline - Moderately brackish water with a salinity range of 5-18 ppt.

Metamorphosis - Developmental changes in the form or structure of an animal.

Molt / Molting - A process where crustaceans and insects shed their exoskeleton (external support).  This is an important growth process, enabling the animal's body to expand.

Mucilage - A sticky, gum-like substance produced naturally by some living organisms.

Nekton ("Swimmers") - The nekton includes all aquatic animals that actively swim in the water column, such as fish or squid. The nekton is one of three divisions of aquatic life; the others are the plankton ("drifters") and the benthos ("bottom dwellers").

Oblique - Slanting and inclined.

Ocellus - An eyelike spot.

Oligohaline - Low salinity; brackish (0.5-5 ppt).

Opaque - Solid, not letting light through.

Ovary - Organ that produces eggs.

Overwinter - Survive the winter, hibernate.

Parapodia - Fleshy paddle-like appendages on each segment of a polychaete’s body.

Parasite - An organism that lives on or within a body and takes its nourishment from the host without giving any benefit.

Paurometabolous - Paurometabolous insects are very similar to hemimetabolous insects. The only difference is that the wings develop externally on the larvae in paurometabolous insects. Frequently it is difficult to distinguish larvae from adults because both live in the same habitat and feed similarly. Development is gradual and the changes in between molts are subtle and barely noticeable.

Parietal - Referring to the cell wall; in close proximity to the cell wall.

Pectoral fins - Fins attached to the shoulder on the side of the body.

Perianth - The outer envelope of a flower.

Periostracum - The flaky leathery outer covering on shells that protects from eroding or dissolving.

Peritoneum - Lining of the abdominal cavity.

Phytoplankton- A type of plant plankton, such as algae, that is the basic food source in many aquatic and marine ecosystems.

Plankton ("Drifters") - The plankton includes all aquatic organisms that are carried passively in the water currents. Most are microscopic (such as diatoms, dinoflagellates, and copepods), but others can be relatively large (such as comb jellies and sea nettles). Plankton is one of three divisions of aquatic life; the others are the nekton ("swimmers") and the benthos ("bottom-dwellers").

Polychaete - A bristle-worm.

Polyhaline - Highly brackish water with a salinity of range 18-30 ppt.

Pores - Small openings in the skin.

Posterior - Behind; the back end of the body or structure.

ppt - An abbreviation for parts per thousand and a measurement of salinity. For example, the open ocean is 35 parts per thousand (ppt). This means that if you had 1,000 buckets of sea water, and could put the salt and water in separate buckets, 35 of the buckets would be filled with nothing but salt.

Process - Any object protruding from the surface of a cell.

Protists - Protists are single-celled eucaryotic organisms in the Kingdom Protista, also called the Kingdom Protoctista. The five kingdoms in R.H. Whittaker's taxonomic system are the procaryotes (procaryotic organisms, including the bacteria and cyanobacteria), protists, fungi, plants, and animals. "Animal-like" aquatic protists (such as copepods) are often called protozoans or zooplankton. "Plant-like" aquatic protists (such as diatoms) are commonly called phytoplankton. However, the protist biologist Lynn Margulis points out that "these organisms are no more 'one-celled animals and one-celled plants' than people are shell-less multicellular amebas."

Pupa (plural is pupae)- The stage in holometabolous insects that occurs after the larval stage, during which the insect metamorphoses into the adult form.

Pupal - The transformational stage between larva and adult.

Pupation - The tranformation between larva and adult.

Pycnocline- The pycnocline is the depth in the water column where there is an abrupt change in density, temperature, and salinity. A pycnocline often forms in the Chesapeake Bay and its tidal tributaries when the lighter, warmer, and fresher water coming downstream from the spring rains overlays the denser, colder, and saltier water of the salt wedge bringing water upstream from the ocean.

Rectal chamber - The chamber at the end of the digestive tract; in dragonfly nymphs this chamber contains gills. A dragonfly nymph can move by jet propulsion by shooting water out of its rectal chamber.

Rhizomes - A form of reproduction where a plant grows an underground offshoot from its roots or stem that surfaces and grows into a new plant at a different location.

SAV- Any Submerged Aquatic Vegetation, i.e., vascular aquatic plants that are rooted in the bottom sediments and grow no higher than the surface of the water, such as eelgrass or redhead grass.

Sessile- Not free to move around; sedentary.

Seta (plural is setae) - Hair-like bristles mostly used for locomotion.

Snout - Fleshy part of the head before the eye and above the mouth.

Spawning/Spawn- A form of sexual reproduction where microscopic eggs and sperm are discharged into the water column.

Subapical teeth - Teeth located just away from the apex (tip) of the mandible (in contrast to apical teeth, which are located on the tip of the mandible).

Subtidal - The zone of the shoreline that is below low tide and is always covered by water.

Spines - Closed or solid structure projecting outward from the cell's surface.

Stolon - An above ground shoot or runner that results in a new plant.

Striae - One or more rows of perforations.

Terminal cell - The last or end cell on a multicellular organism.

Terrestrial - Living or growing on land or in the soil.

Tidal freshwater - Freshwater (0-0.5 ppt) that is tidally influenced.

Turion - A young or emerging shoot.

Undulated - Wavy.

Ventral - Located near or on the lower surface of an animal opposite the back, the belly region.

Whorls - An arrangement of three or more leaves or petals radiating outwards from a single point.