Surtsey Island, which rose from the sea off Iceland’s southern coast in 1963, has been closed to the public for more than six decades as one of the most carefully controlled ecological laboratories in the world.
A study published in October 2025 in the journal Ecology Letters concluded that seabirds — not wind or ocean currents, as had long been assumed — carried the seeds of most of the 78 vascular plant species recorded on the island since 1965.
How the Island Was Born
Surtsey broke the surface of the Atlantic on Nov. 14, 1963, when a submarine volcanic eruption that began at roughly 430 feet below sea level tore through the ocean about 20 miles off Iceland’s southern shore.
The eruption — explosive at first, then effusive — continued until June 5, 1967.
At its largest, the island covered about 1 square mile — and was named after Surtr, a fire giant from Norse mythology.
Since then, marine erosion has reduced its surface to 348 acres, according to a 2008 UNESCO measurement. The organization estimates that, over time, wave action will strip away another two-thirds of what remains, leaving only the island’s hardest volcanic core exposed.
What makes Surtsey unusual is that it endured: unlike most such islands, which surface briefly before slipping back beneath the waves, it stayed.
Scientists note that events of this kind occur only once every 3,000 to 5,000 years.
A Laboratory Closed to the Public
Iceland placed the island under full protection in 1965.
Access was restricted to a small number of authorized scientists operating under strict protocols designed to prevent species from being introduced accidentally.
Landing on the island is prohibited, as is diving in its surrounding waters, disturbing its formations, or leaving any waste behind.
Several decades later, in 2008, UNESCO designated Surtsey a World Heritage Site, citing its ongoing ecological and biological processes.
That policy, sustained for more than six decades, transformed the island into an exceptional case study in island biogeography.
Rarely has science been able to watch, in near-continuous detail, how a completely barren landscape comes to life.
Six Decades on the Record
Scientists began monitoring Surtsey in 1964, just a year after it appeared.
They first documented the arrival of seeds carried by ocean currents, followed by the emergence of molds, bacteria, and fungi. The first vascular plant was recorded in 1965; by 1970, ten species had established themselves.
By 2004, the count had climbed to 60 vascular plant species, along with 75 bryophytes, 71 lichens, and 24 fungi.
The tally also included 89 bird species — 57 of which nest elsewhere in Iceland — and 335 invertebrate species.
Colonization, however, was not a steady, one-way process. Since 2007, researchers have documented a net loss of plant species, and the pace of new arrivals has slowed considerably over the past decade.
The Role Birds Actually Played
The 2025 study, authored by researchers from Iceland, Hungary, and Spain, examined all 78 vascular plant species detected on Surtsey since 1965 and compared their traits against three European classification systems for long-distance seed dispersal.
The findings contradicted the prevailing theory.
Most of those plants lack fleshy fruits, vivid coloring, or other adaptations that traditional models associate with bird-assisted dispersal.
Pawel Wasowicz, of the Icelandic Institute of Natural History and one of the study’s authors, explained that the birds were, in his words, the true pioneers of the island’s colonization — carrying seeds of species that classical theory would never have predicted could travel so far.
Gulls, geese, and shorebirds transported those seeds inside their digestive tracts or deposited them through their droppings, a mechanism known as endozoochory.
Andy Green, a researcher at the Donana Biological Station (CSIC, Spain) and co-director of the study, noted that the findings force scientists to rethink how plants disperse — particularly as bird migratory routes shift in response to global warming.
The evidence is written into the island’s own landscape.
After 1985, a gull colony established itself in the southern sector. The nutrients it left behind helped produce a 32-acre meadow by 2018.
At the northern end, gray seals began gathering to breed each autumn, producing a 5-acre patch of vegetation and, in turn, drawing orcas that hunt the seals.
What Remains to Be Observed
Surtsey remains the only place on Earth where the complete process of biological colonization — from bare rock to a functioning ecosystem of birds, seals, orcas, and dozens of competing plant species — can be traced across seven unbroken decades.
That continuity may not last.
Scientists believe erosion is already threatening the island’s future, and many expect Surtsey to be largely or entirely submerged by the end of this century.
Whatever its fate, this small island stands as a reminder of what nature can accomplish when given time, space, and — above all — the freedom to unfold without human interference.
