Phytoplankton :  Phytoplankton are microscopic plants that float around in the water column. They are the basis of the food web in the ocean.That means that they are food for all the other animals in the ocean. They must live in areas that have a lot of light. The ocean filters out light as it gets deeper, which is the reason the ocean gets colder as you go deeper. For this reason the phytoplankton are typically found in the surface waters to a depth of about 80 meters. They need food and water to live. Phytotplankton are plants, so they need certain basic requirements: light, nutrients, carbon dioxide and water. They get light from the sun, and this requires that they stay close to the surface. Water isn't a problem for them to find, it's all around them. The last requirment, nutrients, is the tough one for them to find. Nutrients are found on the bottom of the ocean in deep water. Phytoplankton cannot swim, so how do they get these nutrients?

An upwelling is the movement of cold bottom water to the surface. Along with this cold water, upwellings bring nutrients to the surface. The phytoplankton would use these nutrients to grow. This results in large populations of phytoplankton in areas that upwell. These large poulations are called phytoplankton blooms.

AVHRR: The Advanced very high resolution radiometer (AVHRR) consists of a four to five channel scanner (depending on the model). These instruments are carried on various satellites such as the TIROS-N and the NOAA-11 satellite. It can sense in the visible, near-infrared, and thermal infrared bands of the electromagnetic spectrum. The AVHRR orbits the Earth at an altitude of 833 km and scans a width of 2399 km. It has a resolution of 1.1 square kilometers and circles the Earth 14 times a day (approximately 100 minutes per orbit).

SeaWiFS:  The purpose of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project is to provide quantitative data on global ocean bio-optical properties to the Earth science community. Subtle changes in ocean color signify various types and quantities of marine phytoplankton (microscopic marine plants), the knowledge of which has both scientific and practical applications. The SeaWiFS Project will develop and operate a research data system that will process, calibrate, validate, archive and distribute data received from an Earth-orbiting ocean color sensor. The concentration of microscopic marine plants, called phytoplankton, can be derived from satellite observation and quantification of ocean color. This is due to the fact that the color in most of the world's oceans in the visible light region, (wavelengths of 400-700 nm) varies with the concentration of chlorophyll and other plant pigments present in the water, i.e., the more phytoplankton present, the  greater the concentration of plant pigments and the greener the water.

Upwelling: Upwellings occur along the eastern boundaries of North America during the summer months. They are events in which warm surface water of the Gulf Stream along the coast is pushed away by prevailing southwesterly winds, and is replaced by cold water rising from the ocean depths. This upwelling of cold water brings nutrients to the surface. These nutrients are associated with algal bloom.

Eddies: A cold-core ring or eddy is a ring of Gulf Stream water flowing counterclockwise around a cold, less saline mass of water. It is formed when a branch of the Gulf Stream meanders and encircles a piece of colder water from the west. A cold ring often can be tracked for 2 years before it dissipates into the surrounding Sargasso Sea, east of the Gulf Stream. A warm-core ring or eddy forms when the edge of the Gulf Stream jogs into the warmer water of the Sargasso Sea and forms a warm-core, clockwise flow of water. This drifts towards the coast and usually dissipates within a year as it collides with the shallow continental shelf. Warm rings trap and transport a variety of different kinds of animals within the eddy, but cold rings carry greater biomass (that is, more life), but less diversity of species. A cold ring traps the nutrient-rich water from the north of the Gulf Stream and transports both nutrients and plankton into the relatively-barren Sargasso Sea. The Gulf Stream and the Sargasso Sea support less phytoplankton-the minute plant life at the bottom of the ocean food chain than the waters directly off the coast.