A $900 million project to expand the Cuban port of Mariel into a strategic hub for shipping in the Atlantic has been painted in Havana as the country’s best opportunity in decades to set a new course for its stagnant economy.

It might also be an ecological calamity, the latest in a series of schemes by Cuba’s all-powerful communist government to boost its economic development at the expense of its nature, according to experts on the island’s environment.

The Mariel project has killed nearly 10 acres of mangroves in the bay and silted the waters of the bay and one of the rivers that feeds into it, said Eudel Cepero, a Cuba-born environmental consultant and activist in Miami.

Working from satellite photos of Mariel available on Google Earth, Cepero said he also measured 20 acres of coves within the bay filled in to expand the port’s container and other land operations, and 25 acres of surrounding land quarried for fill.

Cepero acknowledged that without a first-hand study of Mariel — the starting point of the 1980 boatlift that brought more than 125,000 Cubans to U.S. shores — he cannot definitively establish the environmental damage.

“But if you kill 10 acres of mangrove in the Florida Keys, there’s a revolution,” said Cepero, a lecturer at the University of Miami and Miami-Dade College. “That would be like destroying an entire eco-system.”

“What’s going on (in Mariel) certainly seems alarming,” said Sergio Diaz-Briquets, a Washington-based consultant who co-authored a book on the island’s environmental record, “Conquering Nature.”

Cuba usually gets high marks from the international environmental community for its regulatory framework and the pristine condition of many of its national preserves, especially along its southern coastline.

About one-quarter of its land and marine habitats are legally protected, one of the highest percentages in the world. And Havana has signed many of the key international agreements and declarations on the environment.

Yet, like other developing countries, the government at times has tossed aside environmental and other concerns over projects considered to be strategically needed for economic growth, said Diaz-Briquets.

“The reality is that in the situation that Cuba faces, with economic difficulties, the question becomes whether that (regulatory) framework can be enforced when the very survival of the revolution is at stake,” he said.

The Mariel project is a “once in a century” chance to set a winning development strategy for the country and “probably the biggest investment project today in Cuba,” Havana economist Pedro Monreal wrote in a column last month.

Once completed next year, he argued, the mega-port could easily become a hub for shipping all along the Atlantic, an area expected to grow following the expansion of the Panama Canal that is due to be completed in 2015.

Mariel will have space for 3 million cargo containers, a duty-free zone that could serve the entire Caribbean and bonded assembly plants — “maquiladoras” — that could produce goods for Latin America and Europe, according to official Havana reports.

“No one is thinking about the environment. This is always about jobs and money,” said Dan Kipnis, a Miami activist who has fought the ongoing dredging of the port of Miami. “Why would Cuba be any different?”