T-S diagram	A graph showing the relationship between temperature and salinity as observed together at, for example, various depths in a water column. A T-S diagram for a given station is typically prepared by plotting a point for the temperature/salinity combinations at a range of depths and then joining them by straight lines in order of depth. The resulting line is called the T-S curve.
tar	Any of various dark viscid substances obtained from the destructive distillation of organic matter such as coal, wood, or peat.
taxonomy	1. The branch of biology concerned with the classification of organisms into groups based on similarities of structure, origin, etc. 2. The science or practice of classification. tectonics The study of the processes by which the earth's surface has attained its present structure.
temperate	Region in which the climate undergoes seasonal change in temperature and moisture. Temperate regions of the earth lie primarily between 30 and 60 degrees latitude in both hemispheres.
temperature	The quantitative statement concerning heat. Measured in degrees Celsius, or Farenheit
territorial	1. Of or relating to territory or territories 2. Local or regional.
territorial waters	The waters over which a nation exercises jurisdiction and control.
tertiary treatment (sewage)	If a high quality effluent is required, after secondary treatment, the liquid may be retained in sedimentation ponds or passed through sand or earth filters to remove suspended solids. To reduce plant nutrients, nitrates may be removed by algal growth in remaining ponds, and phosphates can be removed by electrolyte methods.
thermocline	A layer in which the temperature decreases significantly (relative to the layers above and below) with depth. The principal ones are designated diurnal, seasonal, and main thermocline. When measurements do not allow a specific depth to be pinpointed as a thermocline a depth range is specified and referred to as the thermocline zone.
thermophilic	Organisms preferring high temperatures.
tide	The periodic rising and falling of the water that results from the gravitational attraction of the moon and sun acting on the rotating earth. The forces that significantly affect the tides of the oceans are the gravitational forces of the sun and moon, the centrifugal force due to the movement of the earth in its orbit, the Coriolis force, and the frictional force due to the movement of the water with respect to its boundaries
tourist	1. A person who travels for pleasure, usually sightseeing and staying in hotels 2. A person on an excursion or sightseeing tour.
toxicity	A relative measure of the ability of a chemical to be toxic, i.e. to kill or cause an adverse effect. High toxicity means that small amounts are capable of causing death or ill health.
trophic level	In marine ecology, a single level or layer in the transfer of food or energy in a chain. There can be several levels, with distinct size gradations between levels. Organisms that obtain their food by the same number of steps from plants are said to belong to the same trophic level.
tropical	Region in which the climate undergoes little seasonal change in either temperature or rainfall. Tropical regions of the earth lie primarily between 30 degrees north and south of the equator.
turbulence	State of condition of confusion, movement or agitation.