Tourism industries in Mexico and several Caribbean countries are staring at the prospect of a downturn, with large mounds of sargassum, a kind of seaweed, from the Atlantic washing up on beaches along the coastline from Cancun to Belize.
The sargassum on the beaches are emanating foul odors and keeping tourists away.
Scientists are blaming deforestation, releasing of untreated water into seas, and excessive use of fertilizers in the Amazon rainforest area, for the environmental hazard.
Little amount of sargassum is beneficial for the marine life, as it provides habitat for birds and other creatures. However, excessive generation of seaweeds blocks the movement of fish and dolphins, say scientists.
While sargassum began washing ashore in early 2014, the problem has worsened in the past two years.
Hoteliers along the coastline are reporting a decline in tourist numbers, with authorities wondering how to deal with the crisis. Room rates have dropped nearly 20% in some parts of Mexico, according to Spanish news magazine Expansion.
Some hoteliers are reportedly investing their own money in cleaning up beaches. Environmentalists are deeply concerned, because cleaning up the seaweed inadvertently removes sand, potentially aggravating beach erosion.
Mexico claims to have spent US$17 million to clear more than 500,000 tons of sargassum. Tourism accounts for 8% of GDP for Mexico, but in Cancun it accounts for more than 40% of jobs.
Caribbean countries are looking for ways to keep sargassum at bay. The Dominican Republic, for example, is combating the algae with sea barriers.