Israeli Researchers Solve Decades-Old Galapagos Algae Mystery

An Israeli research team, led by Dr. Tal Luzzatto Knaan and doctoral student Omri Nahor from the Leon Charney School of Marine Sciences at the University of Haifa, has resolved a long-standing enigma surrounding the red algae Asparagopsis taxiformis in the Galapagos Islands. For years, scientists were uncertain whether the algae, now common throughout the volcanic archipelago, was native or introduced by human activity, leading it to be classified as cryptogenic (of unknown origin).

The study, published in Diversity and Distributions, employed a "biological detective investigation" combining newly collected samples from 2024 with historical specimens from the Charles Darwin Foundation's natural history collection, along with records from scientific expeditions and past algae surveys. Genetic analysis of samples, including a herbarium specimen from 1985, revealed that all sequenced specimens, from historical to recent, belonged to the same genetic lineage, L2. This lineage is not known from other parts of the Eastern Pacific, with the closest known population located in Hawaii, approximately 5,000 kilometers away.

This genetic uniformity over four decades, coupled with historical data, suggests the algae is not an ancient, isolated native population. Surveys from the 1930s did not reliably document Asparagopsis taxiformis, but by 1962, after increased maritime traffic and the establishment of military bases during and after World War II, it was described as abundant on Santa Cruz Island. The researchers hypothesize that the algae likely arrived in the Galapagos via ships during or shortly after World War II.

This research is significant not only for identifying an invasive species but also for demonstrating the power of DNA analysis to reconstruct biological history. The study marks the first molecular survey of this algae in the Galapagos and confirms it as the first introduced algae species in the archipelago. 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. Luzzatto Knaan noted that the algae has also invaded the coasts of Israel and other Mediterranean regions, where its effects on other species are already being observed. She described it as one of the "100 worst invasive species," despite its potential applications due to its chemical compounds.