A barcode for life
The Bay of Fornells, on the north coast of Menorca, is part of a marine reserve established in 1999 to protect its biodiversity. This protected status and good water quality make it an ideal habitat for hundreds of marine species. For years, its underwater world was considered well-documented. A project by researchers from the Centre for Advanced Studies of Blanes (CEAB-CSIC) and the University of Barcelona challenged that assumption by applying a modern technique called genetic barcoding to the bay's algae.
Genetic barcoding acts like a supermarket scanner for species. Instead of relying only on physical appearance, which can be misleading in simple organisms like algae, scientists analyze a short, standardized section of an organism's DNA. For animals, this is the mitochondrial gene COI, but for algae, genes like rbcL or tufA are often used. By sequencing this small DNA fragment, researchers can quickly and accurately identify a species and compare it to a global database. The team from CEAB-CSIC used this method to build a comprehensive inventory of algal life in the bay.
An unexpected discovery
The results of the project, "Codi genètic de les algues de les Illes Balears" (Genetic Code of the Algae of the Balearic Islands), were surprising. The team cataloged more than 200 distinct species of algae from the seabed in this single bay. The DNA barcodes revealed that 15 of these species had no match in any existing database. They were entirely new to science. This discovery in such a popular, well-studied part of the Mediterranean shows biodiversity remains uncounted.
The finding demonstrates that even in familiar waters, entire species can live undetected. The simple forms of many algae make them difficult to distinguish visually, a problem DNA analysis solves. The identification of these 15 new species confirms that the true extent of marine biodiversity is significantly underestimated. The protected waters of the Northern Menorca Marine Reserve, which covers over 5,000 hectares, clearly harbor more secrets than previously imagined. The reserve's restrictions on fishing and its varied seabed habitats, including important communities of Cystoseira algae and Posidonia seagrass, create a sanctuary where this diversity can thrive.