Early on November 14, 1963, ash and steam broke the surface of the North Atlantic about 18 kilometers southwest of Heimaey in Iceland’s Westman Islands. The eruption had likely begun days earlier on the sea floor,130 meters below the surface, before hot magma and cold seawater built something visible above the waves.
By the next day, a new island had formed. Iceland later named it Surtsey Island, and scientists quickly recognized that it offered a rare chance to watch life arrive on land that had not existed before.
More than six decades later, Surtsey is still serving that purpose. The island remains one of the clearest natural laboratories for studying how life colonizes new land, especially because human access has been tightly restricted since its early years.
A study published in Ecology Letters examined how vascular plants colonized Surtsey after its birth. Its central finding is simple but important: many of the plants that reached the island did not have the classic traits usually linked to long-distance dispersal. Instead, the researchers reported, birds carried most of them.
A Volcanic Island Appeared in 1963
The Surtsey Research Society states that the eruption began with explosive phases because seawater rapidly cooled the hot magma, turning it into tephra, or volcanic ash. By January 1964, the new island had reached an elevation of 174 meters, or more than 300 meters above the sea floor where the eruption began.
The eruption did not follow a single, simple pattern. Activity shifted between vents, submarine eruptions formed nearby features, and two small islands, Syrtlingur and Jólnir, briefly appeared before the ocean destroyed them. Surtsey survived because later lava flows gave parts of the island a stronger structure.
Lava began erupting on Surtsey on April 4, 1964, from the western crater. By the time that lava phase stopped on May 17, the island had grown to 2.4 square kilometers. A later lava eruptionbegan on August 19, 1966, and continued until the Surtsey eruption ended in early June 1967.
By then, the eruption had lasted more than three and a half years. The Surtsey Research Society says the island covered 2.7 square kilometers, and the eruption had produced 1.1 cubic kilometers of volcanic material. About 60 to 70 percent of that material was tephra, while 30 to 40 percent was lava.
Protection Kept the Natural Lab Clean
Surtsey’s scientific value depends on keeping human influence low. Iceland declared the island a nature reserve in 1965, and the preservation declaration was renewed in later decades.
The goal, according to the Surtsey Research Society’s conservation rules, is to make sure plant and animal colonization, biological succession, and geological formation develop as naturally as possible. That means visitors cannot simply land there.
A permit from the Surtsey Research Society is required to visit the island. The rules also prohibit disturbing anything, transferring living animals, plants, seeds, or plant parts to the island, and leaving waste on or near it.
Those rules matter because a single seed carried by a person could change the record scientists are trying to read. Surtsey is valuable because its plants and animals have arrived with little direct human interference. That makes it one of the few places where researchers can study primary succession on newly formed land in real time.
Primary succession is the slow development of life on a surface without established soil. On Surtsey, that meant bare volcanic material, sea spray, wind, waves, birds, and time.
Birds Carried Plants to Barren Land
The study described by the Estación Biológica de Doñana focused on 78 vascular plant species recorded on Surtsey since 1965.
For decades, ecologists often expected remote islands to be colonized mainly by plants with special dispersal traits. Fleshy fruits, for example, were thought to help because birds could eat them and later spread their seeds. Other seed or fruit shapes were also treated as clues to how well plants might travel long distances.
The researchers found that most of Surtsey’s vascular plants lacked those expected long-distance dispersal traits. According to the CSIC report, gulls, geese, and shorebirds instead appear to have carried seeds to the island in their guts or droppings.
That finding changes the emphasis from seed shape alone to animal movement. Birds did not just visit Surtsey after plants arrived. The study reported that they helped bring many of those plants in the first place.
Dr. Pawel Wasowicz of the Natural Science Institute of Iceland, one of the study’s authors, said birds were “the true pioneers of Surtsey” because they carried seeds of plants that conventional theories did not expect to reach the island.
Dr. Andy Green of the Estación Biológica de Doñana, who co-led the research, said animals, especially birds, are key drivers of plant dispersal and colonization.
The report also says the study calls for ecological models that account for real biological interactions instead of relying only on seed traits or plant classifications.
Ocean Erosion Keeps Changing the Island
Surtsey is not a fixed platform for this experiment. The island has been shrinking since the eruption ended.
The Surtsey Research Society reports that strong winds are common in the Westman Islands area, and ocean waves cause heavy shore erosion. During an extreme storm on January 8 and 9, 1990, average wave height southeast of Surtsey reached 14 meters, with the highest waves estimated at about 20 meters.
In the first years after the eruption, 3 to 20 hectares of land disappeared each year. More recently, the average loss has been about 1 hectare per year.
Surtsey has not vanished because two features have helped protect it. Lava from the 1964 to 1965 and 1966 to 1967 eruptions shielded some of the loose tephra. In other areas, tephra hardened into palagonite tuff, creating a tougher core.
Even so, the island is much smaller than it was at its peak. As of 1975, Surtsey had decreased to 2.0 square kilometers, and by 2002 it had shrunk to 1.4 square kilometers, or 52 percent of its maximum size in 1967.