Scientists discover nearly pristine ecosystems on two Pacific atolls

On a planet where human impact has spread from the depths of the oceans to the tops of mountains, Bikar and Bokak, two remote atolls in the Marshall Islands, appear to have preserved their nature almost completely intact. Researchers rank them among the wildest and best-preserved marine ecosystems in the world.

The atolls are the northernmost in the Marshall Islands: Bikar is 115 kilometers, while Bokak is 384 kilometers from the nearest inhabited area.

A scientific team visited both areas during an extensive expedition in 2023. The researchers mapped the vegetation, examined seabird and shorebird populations, identified turtle nesting sites, and surveyed coral reefs and fish communities.

The expedition also included research in the depths of the ocean. For this work, the team used diving equipment, underwater cameras, deep-sea recording systems and a submersible, collecting data on a wide range of marine life.

The study identified 15 colonies of seabirds that were breeding or could potentially breed in these areas. Hundreds of different groups of fish and marine predators, including sharks, were also recorded. Two of the species observed may be previously unknown to science.

The researchers also documented 132 nests of green sea turtles, almost all of them on Bikar Atoll.

Although they share many similarities, the atolls display ecological differences: Bokak has greater reef-fish biomass and more abundant corals, while Bikar is distinguished by a greater diversity of algae.

The study’s lead author, Dr. Alan Friedlander, a marine ecologist at the University of Hawaii, said this was the first comprehensive ecological assessment of the Bikar and Bokak National Marine Reserve. He called the areas treasures for the Marshall Islands and the planet, praising the Utirik Atoll community for their traditional protection over the decades.

The findings served as the basis for creating a 48,000-square-kilometer marine protected area around the two atolls. It is the first national marine protected area in the Marshall Islands.

According to Dr. Friedlander, these territories also have value as reference points for scientific research: they give researchers the opportunity to observe how marine ecosystems function when human impact is limited.

However, their remoteness does not completely shield the atolls from climate change. Ocean warming, coral bleaching, rising sea levels and changes in marine productivity are threatening even the most distant coral reefs.

The study was published in the journal “Frontiers in Marine Science.” The authors emphasize that Bikar and Bokak could serve as natural laboratories for understanding the characteristics and functioning of healthy marine ecosystems, as human impact becomes increasingly evident in the world’s oceans.