Israeli Researchers Solve Galapagos Algae Mystery Using DNA

An international research team, led by Israeli scientists from the University of Haifa, has resolved a decades-old mystery regarding the red algae Asparagopsis taxiformis in the Galapagos Islands. For years, it was unclear whether the algae, now common throughout the archipelago, was native or introduced by human activity. Due to this uncertainty, it was classified as a cryptogenic species, meaning its origin was unknown.

The study, published in Diversity and Distributions, employed a "biological detective investigation" combining genetic analysis of recent samples collected in 2024 with historical specimens dating back to 1985, as well as historical expedition records. By analyzing three genetic markers and comparing them to global sequences, researchers traced the algae's "fingerprint" over decades.

All sequenced samples belonged to the same genetic lineage, L2, which is not known from other parts of the Eastern Pacific. The closest known population is in Hawaii, approximately 5,000 kilometers away. This genetic uniformity over four decades, coupled with historical data, suggests the population is not ancient or isolated.

Historical surveys from the 1930s did not reliably document Asparagopsis taxiformis in the Galapagos. However, by 1962, after World War II and increased maritime activity including military bases, the algae was reported as abundant on Santa Cruz Island. This historical context, combined with the genetic findings, leads the researchers to believe the algae likely arrived via ships during or shortly after World War II.

This research highlights the power of using DNA as a "time machine" to reconstruct biological history, linking current samples with decades-old herbarium specimens. The study marks the first molecular survey of this algae in the Galapagos, officially identifying it as an introduced species. The findings have implications for conservation, as Asparagopsis taxiformis produces compounds that may give it an advantage over native species. While its ecological impact in the Galapagos is still under investigation, its widespread presence necessitates monitoring and risk assessment for the unique marine ecosystem. Dr. Tal Lotan-Kanaan noted that the algae has also invaded the Mediterranean, including Israel's coast, and is considered one of the world's worst invasive species, despite its potential for chemical applications.