Gyre 
A giant circular oceanic surface current 
Insolation 
Rate of delivery of direct solar radiation per unit of 
horizontal surface 
Intergrade (Vv) 
To merge gradually, one with another, through a 
continuous series of intermediate forms 
Intergrade (n) 
An intermediate form 
Macrophytes 
Large aquatic plants or seaweeds 
Mesoscale 
Of, or relating to, a meteorological or oceano- 
graphic phenomenon approximately 1 to 100 km 
in horizontal extent 
Mesotrophic 
Having a moderate amount of dissolved nutrients 
Movie loop 
A piece of film whose ends are spliced together 
so as to project the same material continuously 
Oligotrophic 
Deficient in nutrients and plant biomass 
Phaeophytin-a 
Degradation product of chlorophyll-a 
Phytoplankton 
Single-cell, drifting algae of the sea and other 
bodies of water. Most require only carbon diox- 
ide or carbonates as a source of carbon and in- 
go organic nutrients for metabolic synthesis. 
Phytoplankton pigments 
Any of various photosynthetic pigments of which 
chlorophyll-a and phaeophytin-a are usually the 
dominant components 
Plankton 
Passively floating or weakly swimming animal and 
plant life of a body of water 
Recruitment 
The addition of young to a natural population 
Trophic level 
One of the hierarchical strata of a food web 
characterized by organisms that are the same 
number of steps removed from the primary pro- 
ducers 
Troposphere 
The portion of the atmosphere below the strato- 
sphere that extends outward about 7 to 10 miles 
from the Earth's surface and in which tempera- 
ture generally decreases rapidly with altitude, 
clouds form, and convection is active 
Zooplankton 
Animal plankton 
Acronyms 
APT 
Analogue Picture Transmission 
AVHRR 
Advanced Very High Resolution Radiometer 
CZCS 
Coastal Zone Color Scanner 
ESA 
European Space Agency 
