Professor Laurence Mee, 63, collapsed while on business for the Scottish Association for Marine Science (SAMS) in Inverness on Tuesday.
Friends and colleagues at the facility at Dunstaffnage, near Oban, which is part of the University of the Highlands and Islands (UHI), paid tribute to the internationally recognised expert.
Marine ecologist Abigail McQuatters-Gollop wrote on the micro-blogging site: "A great loss to marine science. My friend, my mentor. We'll miss you, Laurence."
Michael Gibson, chairman of the board to SAMS, said "He not only freely contributed ideas but also acknowledged those of others. He presided over an organisation that was proactive and successful."
Education Secretary Michael Russell said he was shocked and saddened.