Although there is some disagreement, several types of marine ecosystems are largely agreed on: estuaries, salt marshes, mangrove forests, coral reefs, the open ocean, and the deep-sea ocean. An estuary is a coastal zone where oceans meets rivers.

Salinity, or high salt content, and global circulation make marine ecosystems different from other aquatic ecosystems. The organisms that inhabit various marine ecosystems are as diverse as the ecosystems themselves. They must be highly adapted to the physical conditions of the ecosystem in which they live.

Principle 5g: There are deep ocean ecosystems that are independent of energy from sunlight and photosynthetic organisms. Hydrothermal vents, submarine hot springs, and methane cold seeps rely only on chemical energy and chemosynthetic organisms to support life.

The deep-sea is the largest habitat on earth. The area reaches over 4 000m in depth and covers 53% of the sea’s surface, which in turn covers 71% of the world’s surface! The continental slopes alone occupy 8.8% of the world’s surface, compared to 7.5% for the continental shelf and shallow seas (see Figure below).

PEOPLE really can worry themselves to death, according to the largest study ever to link distress and mortality. Research published today found even low levels of stress, which patients would rarely discuss with their doctor, raised the risk of dying, particularly from heart disease and strokes.

Treating phobias Almost all phobias can be successfully treated and cured. Simple phobias can be treated through gradual exposure to the object, animal, place or situation that causes fear and anxiety. This is known as desensitisation or self-exposure therapy.