Scientists will be trawling the depths off the Sussex coast for new a insight into what dwells down below.

The £450,000 project starting today is aimed at both protecting wildlife and boosting the construction industry's ability to supply everything from new hospitals to patios.

Marine biologists and geologists will use the latest dredging and video equipment to record the thousands of plants and sea creatures.

The work is being managed by experts from environmental consultants Emu and will provide evidence for English Nature and the Government.

The research will also inform decisions on new applications to dredge sand and stone from the seabed for the building and construction industry.

The scheme stretches from the Isle of Wight to Eastbourne, with special emphasis on a patch of coastline south of Littlehampton.

More than 13.5 million tonnes of aggregate a year is used in building in London and the Home Counties, according to companies in the industry - five tonnes for each person.

But underwater sites licensed for dredging are running out and the industry's attention has turned to the UK's continental shelf off the South Coast. The Office of the Deputy Prime Minister is considering seven applications for the Eastern Channel between 16 and 27 miles from the coastline.

The study will examine exactly what plants, sea life and fish live near the sandbanks and what measures will be needed to protect them.

Over the next 12 months, experts will examine most of the South Coast, thanks to a £225,000 aggregates levy sustainability fund grant from English Nature. Nigel Thomas, Emu's technical director in charge of the project, said: "We won't be dredging the seabed, just taking small sample particulars, about 0.1sqm each, to establish what the environment's like.

"The survey will probably cover a ten-day period and after taking the grabs, we'll come back and do some video work."

Simon Shaw, managing director of Southampton-based Emu, said: "The increased knowledge provided by this project's results will give the Government and its advisors greater confidence when considering applications for new dredging areas."

Victoria Copley, marine operations advisor to English Nature, said: "This project will provide valuable guidance to English Nature and other regulatory authorities when making decisions on aggregates dredging and other industrial uses.

"We believe the research will tell us whether the seabed communities associated with sand and gravel deposits are unique to those areas or are common to the entire marine environment."

David Harding, of the British Marine Aggregate Producers Association, said new licence applications were not dependent on the study but the dredging operation would be informed by the results.

He said: "We do have to see if the wildlife on the sandbanks is any different to other parts of the sea bed. If it is, greater care may be needed when looking at extraction.

"We do have to remember only one-tenth of one percent of the continental shelf will be affected."

The findings will be published by the Wildlife Trust at www.southeastmarine.org.uk