Last month staff at the University Marine Biological Station in Millport, on the island of Cumbrae, were told the facility could be shut down in 2013.
The Higher Education Funding Council for England had withdrawn the £400,000 which it gives London University to run the station.
Thousands of students have been stationed at Millport while on field trips, and its closure would end more than 125 years of history that began when marine biologist Sir John Murray set up a floating laboratory in a disused barge at Port Loy.
In an open letter to the Scottish Government, the academics said they were "deeply concerned" at the threat to the station which they said should be saved.
One of the signatories was Mark Blaxter, professor of evolutionary genomics at Edinburgh University. He said: "It is recognised across all the universities that it is an essential part of our national capabilities. It is like a national treasure.
"It is unique in Europe. It has been underfunded and under-resourced in the last few decades and to throw it away at this point would really be a tragedy because once you disperse all the skills and knowledge of the people who are working there, it would never get started again.
"How the problem is solved is unclear, because it does take money, and money is tight. But the universities' argument would be that money should be found because it is a unique, nationally and internationally important resource."
In December, Alex Salmond told First Minister's Questions the centre was "not actually used by any Scottish university at present". But Mr Blaxter said he thought the First Minister was misinformed.
The Scottish Government said it would "continue working hard to explore options" for the site.
The Cumbrae Community Development Company (CCDC) is also trying to save the station, which it says contributes £2.5 million to the Scottish economy every year and is the third-largest employer on the island.
The open letter added: "We urge academic and political leaders to work towards securing its future as an inspiring centre for marine science in Scotland.
"Many, many thousands of Scottish students have attended and been inspired by the facilities of the station."
London University said a decision over whether to close the station would be discussed at a meeting on January 30.
Other academics who signed the letter were based at Glasgow University, Heriot-Watt University, the University of the West of Scotland, Stirling University and Edinburgh Napier University.