ascidian: a minute sedentary marine invertebrate with a saclike body

ballast: heavy material in a ship to provide stability

bryozoans: a stalked marine or freshwater animal that forms colonies

diatoms: marine or freshwater one-celled algae

glass transition temperature: temperature at which materials change from hard and brittle to soft and pliable

humic: material obtained from organic matter of soils, produced by decomposition of plant or animal matter

hydroids: an asexual animal with a single internal colony; hydroids grow in branching colonies

immunoglobulins: antibody or protein found in the blood

trawls: Strong nets dragged along the ocean floor for catching deep dwelling fish

uronic acid: acid compounds that are oxidation products of sugar; are found in many polysaccharides and in urine