THE OPEN SEA
Food in tiny packages
The sea is full of tiny plants and animals, which are food for many of the larger forms of life in the sea and on the seabed. They are called 'plankton' and are moved by the tides and currents. The photograph shows many different types of the tiny plants which are called phytoplankton. There may be as many as 20,000 phytoplankton (approximately one half of the number of people who live in Inverness) in just a bucketful of sea water.
In late spring and early summer the tiny plant plankton, phytoplankton, grow in numbers as the days become longer, the water temperature increases and the water becomes holds more nutrients. The phytoplankton may increase to vast numbers, and can produce 'algal blooms'.
These plant plankton are eaten by swarms of tiny animals which are called zooplankton, that are smaller than a grain of rice. Zooplankton are an important source of food for small fish, which are themselves a vital food source for larger commercial fish and many seabirds. These links between bigger animals eating smaller animals make up a food chain. If any of the plants or animals are removed from the food chain, for example by overfishing, pollution or natural causes, the animals further up the chain will suffer.