New research could change the way we see the importance of the creatures at the bottom of the food chain, a Derby scientist said.

Marine biologist Phil Carey, from the University of Derby, is conducting research into how many amoebae live in the world's oceans.

He said his research could show the tiny single-celled organisms play a far more important role in the energy flow between microscopic organisms in the ocean than previously thought.

Amoebae feed on bacteria in the water - the very beginning of the food chain. They are 100 times bigger than bacteria, but cannot be seen by the naked eye.

The only other study to date which tried to estimate the numbers of the organisms in oceanic waters took place in the 1970s, when an American team of scientists estimated there was just one amoeba in a litre of water, the university said. But by using new microscopic equipment to analyse samples, Dr Carey discovered between 1,600 and 10,000 amoebae in a litre sample of water taken during research in the Maldives.

He is now planning further studies but said: "This initial study suggests there is an astounding number of amoebae in our oceans and it increases the number of important organisms that we know about.

"The transfer of energy from bacteria in the ocean to larger organisms such as zooplankton depends on single cell organisms such as amoebae.

"There is a link between the bacteria and the zooplankton and we can conclude that the amoebae play a major role in the transfer of energy between the two groups."

He said similar organisms - ciliates, which also feed on bacteria in water - had long been known to make up a large population in water. But the suggestion there are more amoebae in water than previously thought may change the way people think about the carbon cycle, he said.

He added: "This study has revealed far greater numbers than had been previously found, especially in the neustonic zone where they are clearly playing an important role in the transfer of energy to higher trophic levels of oceanic food webs."

He said they were competing with other organisms to transfer energy from bacterial groups to smaller zooplankton that cannot feed on bacteria directly, adding: "This research suggests we must consider for the first time that the amoebae are making an important contribution to energy flow between microscopic organisms in the open ocean."

Following his further studies and samples, Dr Carey is looking to publish his findings at the end of the year.