The Surprising Story Of Bonaire's Salt Pyramids


History is about connecting the dots. Sometimes those dots begin and end in the strangest places. The salt pyramids of Bonaire are not just an iconic landmark that greets incoming tourists to the island, they are also an integral part of the island’s history. Salt was once a critical element in the complex trade relations that tied together the original 13 American colonies with the Caribbean and West Africa.

Deep in the central Caribbean, just 60 miles from Venezuela, the island of Bonaire is a tiny, 112-square-mile island, in the Leeward Antilles. Along with its neighbors Curaçao and Aruba, it forms the “ABC” islands. Formerly part of the Netherland Antilles, it became a legal “municipality” of the Netherlands in 2010, when the Netherland Antilles was dissolved. Two other, uninhabited islands of the Leeward Antilles, Klein Bonaire (Little Bonaire) and Klein Curaçao (Little Curaçao), make up the rest of the island grouping.

The island of Bonaire consists of a core of volcanic rocks overlain by a mix of largely carbonate rocks and associated fringing coral reefs. The entire structure was uplifted approximately 90 million years ago, along with the rest of the Leeward Antilles and the Venezuelan Antilles, when tectonic activity caused by the Caribbean continental plate pressing against the South American plate forced the ancient seafloor to buckle and rise above the surface of the Caribbean Sea.

As the land steadily uplifted, coral reefs formed in the shallow waters that surrounded the slowly rising island. As those reefs broke the surface, newer reefs on the fringes of the island replaced them. Over millions of years these ancient reefs became part of the topography of the island. Vibrant coral reefs still ring the relatively shallow coastal waters on the Caribbean side of the island, making it a scuba diving mecca. Many of the reefs on the Caribbean side, especially on the southeast side of the island, are less than 50 feet from the shore.

About 300,000 tourists come to Bonaire every year. Approximately 170,000 of those visitors come on cruise ships. The island is a popular stop on east Caribbean itineraries for a number of cruise companies. Week long scuba diving vacations are also a popular attraction.

One of the most notable features that greets arriving visitors, both by sea and by air, is a distinctive line of white salt pyramids at the southeastern end of the island. Each pyramid, roughly 50-feet high, contains approximately 10,000 metric tons of 99.6 percent pure salt. Depending on the time of the year, there can be upwards of 200,000 metric tons of salt neatly stacked in long rows awaiting shipment.

The solar salt facility, one of the largest in the Caribbean, is today owned by Cargill, the Minneapolis, Minnesota based conglomerate. The facility covers approximately 13 percent of the island, about 16 square miles of land on the flat, southeast corner. The entire location is only a few feet above sea level.

The operation utilizes a series of 250-acre condenser ponds. Saltwater drawn directly from the Caribbean, at around 3.5 percent salinity, or from the adjoining brine lake, the Pekelmeer (Dutch for brine lake), at five percent salinity, moves through a succession of condenser ponds where the salinity of the brine is successively increased as the unrelenting sun and wind steadily evaporate the water.

When the brine reaches between 25 percent and 30 percent salinity it is moved into crystallizer ponds. As the evaporation of water increases the salinity beyond 37 percent, the salt begins to crystallize and precipitate out of the brine solution. Eventually it will form an 8 to 10-inch layer of virtually pure salt. The entire process takes 10 to 12 months, depending on the prevailing temperature and wind, as well as the precipitation and the degree to which dust and other contaminants in the air provide the nuclei that spur the crystallization of the salt.

Once harvested, the salt is washed in salt water to eliminate the small quantities of calcium sulfate dihydrate (gypsum), which is mixed in with the salt. The washed salt, more than 99.6 percent pure, is then stacked into Bonaire’s iconic and unmistakable salt pyramids. This facility can produce between 300,000 and 500,000 metric tons of salt annually. It is exported all over the world in roughly equal portions to Europe, Asia and North America.

One of the characteristic features of salt produced by solar dehydration is the size of the resulting salt crystals. Unlike “rock salt” from sub-surface mines, or salt obtained from brine solutions created by injecting hot water into underground salt deposits, salt obtained from “natural” processes, like solar dehydration, produces much larger crystals of salt. Nicknamed “sun gems,” these large crystals are particularly prized for use in water softeners and swimming pools. Bonaire salt finds a myriad of other uses, from the dinner table, to a variety of industrial processes, including the production of chlorine gas for water treatment to the more prosaic use to de-ice roads in winter.

What is even more remarkable is that the solar salt facility also houses the largest pink flamingo sanctuary in North America. As the salinity of the salt ponds increase, they each produce a distinctive ecology. Various kinds of algae and Halobacteria, an archaic precursor to bacteria, thrive in the super salty water giving the ponds their distinctive pinkish coloration. Different levels of salinity create different floras of algae and bacteria and in turn different colors in the saltpans. These organisms use the pigment bacteriorhodopsin, rather than chlorophyll, to create energy from sunlight in a chemical process unrelated to conventional photosynthesis.

Brine shrimp thrive on the algae and bacteria and the flamingoes in turn thrive on the brine shrimp. The rhodopsin pigment in the bacteria is concentrated in the brine shrimp, and is in turn absorbed by the flamingoes, resulting in their brilliant pink plumage. This is the same phenomenon that is found in the pink flamingoes in the briny lakes of the Great Rift Valley in East Africa. Cargill is to be complemented for successfully managing the complex ecology of a world-class nature reserve in the middle of an equally sophisticated, world-class, industrial-sized solar salt facility.

While the salt pyramids of Bonaire, and their equally picturesque pastel colored salt ponds, are unmistakable to the visiting tourist, what is less appreciated is that these salt works are just the most recent manifestation of the Caribbean’s centuries-old salt trade. Salt, one of the most common minerals on earth and by weight among its least expensive, was, historically, at the center of a complex web of trade relations, especially from the mid-sixteenth century through the early nineteenth century, which had a profound effect on the history of the Caribbean and indirectly, even on the history of the original 13 colonies that would eventually form the nascent United States.

The Spanish arrived on Bonaire in 1499, and briefly settled the island. They collected the naturally occurring salt deposits that were found along the low-lying southern shore of Bonaire—using the salt to preserve beef. It was the Dutch, however, who would begin the Caribbean's salt industry, dominating the trade in salt for the better part of three centuries.

At the time, Spain was one of the largest producer of salt in the world, utilizing both saltpans along the Mediterranean coast and, in particular, a huge deposit of rock salt, called the Muntanya de Sal (Mountain of Salt) in Cardona, Catalonia. According to Mark Kurlansky, in his book Salt: A World History, the theoretical value of Spain’s salt deposits in the fifteenth century exceeded the entire value of its gold and silver reserves.

The Dutch were extensive users of salt due to their commercial interest in the Baltic herring and the North Sea cod fisheries. Both activities required large quantities of salt to preserve the fish catch. The revolt of the nine “northern provinces” and their organization into the Dutch republic under William of Orange in 1581, precipitated 80 years of warfare between the Dutch and the Spanish and cut Dutch merchants from their traditional supplies of Spanish salt.

Looking for new sources of inexpensive salt, the Dutch found a veritable bonanza of salt in the Caribbean. They would go on to produce salt on all three of the Leeward Antilles, as well as on St. Martin and the other Dutch islands in the Lesser Antilles further east. It was Bonaire, however, that would be the center of the Dutch trade in salt. From the very beginning, Caribbean salt would be exported all over North America, as well as back to Europe.

From the mid-sixteenth through the early nineteenth century, Caribbean salt flowed north to the massive cod fisheries of Newfoundland’s Grand Banks and those of New England. Those fisheries, the single largest new source of animal protein in the world from the sixteenth through the eighteenth centuries, required between 25,000 and 50,000 tons of salt per year. Salted cod, the cheapest form of protein available, flowed south and came to play a prominent role in the diet of slaves in Caribbean sugar plantations; especially during the West Indies sugar boom from the mid-seventeenth century through the beginning of the nineteenth century.

To this day, salted cod features prominently in the national cuisines of the islands of the West Indies, even though cod is not native to the Caribbean and the closest cod fishery is more than 2,000 miles to the north of the West Indies. Dishes like Green Fig and Salt Fish, the national dish of St. Lucia, or Salted Cod Fish Cake in Barbados, have long been staples of local diets. Indeed, what was once dismissed as being of little value except for “slave food” is now at the center of a Caribbean nouvelle cuisine, which looks to integrate traditional “slave food based” West Indies cuisine, with a modern “culinary fusion” inspired menu.

In addition, molasses, an important byproduct of the production of sugar, flowed north to New England and the mid-Atlantic colonies of British North America. There it was converted into rum, where it formed a critical branch in the "triangular trade” between North America, West Africa and the Caribbean.

At the time of the Revolutionary War, the American colonies were second only to Barbados in rum distillation. There were at least 140 distilleries in the 13 colonies and the number may have been substantially higher. Massachusetts had 63 distilleries, Rhode Island had another 33 distilleries, 20 of which were in Newport. An additional 44 distilleries were scattered among the other colonies.

The industry was among the largest in North America. According to Wayne Curtis, Colonial America was annually producing more than 5 million gallons of rum. Rum exports represented approximately 80 percent of the value of New England's foreign trade. The rum industry, in turn, drove other industries like cooperage and iron working. The distillers required around 100,000 barrels a year just to hold each year’s production.

Rum from New England flowed back across the Atlantic to the “slave coast” of West Africa where it was traded for newly captured slaves. In turn, those slaves were transported across the Atlantic in the notorious middle passage to the Caribbean where they were traded for salt and molasses. Those items were brought to New England where they were used to preserve the cod catch as well as cheese and other foodstuffs to reexport to the West Indies and to make more rum.  The process repeated itself like clockwork for the better part of almost two centuries. At the center of this complex web of trade relations was none other than the Caribbean’s ubiquitous salt, and at the center of that salt trade were Bonaire’s historic salt lagoons.

Today, the trade in West African slaves has, thankfully, long since been abolished. New England is no longer a major producer of the world’s rum, although new craft distilleries are once again producing it. The Caribbean salt trade, however, perseveres and Bonaire's central role at the heart of the region’s salt industry remains unchanged.

I am indebted to the Cargill Company and to Gary Rimmey, the General Manager of Salt Bonaire, B. V., for very generously allowing me to visit their facility.

Joseph V Micallef