Land Animals Can Raft Across Oceans

A research study about floating plastic debris illustrates how animals can cross oceans on floating rafts.

It’s a huge worry: plastic waste floating in the ocean is harming whales, dolphins and other sea creatures. But it can also serve as a transportation system for small animals. A press release from the University of Florida explains how various species can hitch a ride on barnacles and mussels that are able to fasten onto slick plastic bottles.

University of Florida researchers discovered that diverse communities of rafting animals can inhabit even the smoothest pieces of plastic debris if barnacles step in first to create complex habitat, similar to trees in a rainforest or corals in a reef. That means plastics could better transport foreign species across oceans than previously believed, said Mike Gil, who, as a doctoral candidate at UF, led the study published Jan. 27 in Scientific Reports.

A new worry is that invasive species can migrate to distant coastlines and upset local ecologies. While it’s true that animals aren’t supposed to do this—and it’s humans’ fault for polluting the seaways—the researchers recognize that long-distance ocean transport is as old as the hills:

Before plastics, rafting communities in the ocean were limited because of a limited number and lifespan of natural floating rafts, like downed trees, seaweed or pumice. Over the last 40 years, however, the amount of oceanic plastic waste has increased at an alarming rate, and the lifespan of these artificial rafts can vastly exceed that of natural rafts.

Very large rafts can be made by tsunamis, volcanoes, or other natural phenomena. Researchers studied barnacle-infested plastic waste coming from an estimated “1.5 million tons of floating debris deposited into the Pacific Ocean during the Tōhoku tsunami, which took place in Japan on March 11, 2011.”

Natural rafts (e.g., wood, pumice and marine vegetation) are generally characterized by low or patchy abundance, limited longevity, and relatively high habitability, due to high surface rugosity, structural complexity, and biodegradability. Historically, natural rafts provided the only opportunities for rafting dispersal, leading to infrequent or episodic oceanic dispersal events.

The authors are rightly concerned about the vastly increased rafting surface area provided by plastic trash. But whether a floating raft is natural or artificial, they recognize that anything clinging to a large-enough raft floating in a prevailing current might be able to establish a foothold on a distant continent. Over thousands of years, a significant amount of rafting could occur even if episodic or infrequent.

Secular scientists recognize the ability of floating rafts to distribute life around the world. While they need this idea to get old-world monkeys to South America, creationists can appeal to the same process to explain some species becoming globally distributed after the Flood. What’s fair for the evolutionist is fair for the creationist. Some creation geologists expect large floating “islands” of vegetation surviving after the Flood, as well as land bridges from lower sea levels. Birds can also transport eggs and seeds of some creatures over long distances.