Video footage has emerged of “giant worms” appearing on beaches along the west coast of America in their thousands, as a direct result of climate change.
Scientists at Oregon State University have warned that these “worms” are posing a threat to marine ecosystems by compromising the food chain.
The intense heat in the last few months has led to the sighting of these strange transparent creatures that can reach up to 18 metres in length. In some instances, they have grown so large that humans can swim through the internal cavity.
These creatures – known as pyrosomes – live in waters with warm temperatures of up to 30C and in areas where large amounts of microscopic plankton live, which are gradually concentrating in more areas of the planet due to higher temperatures.
This has led to mass mortality events, impacts on fisheries and documented changes in the abundance and distribution of species, including, the increase of pyrosomes and the decrease of jellyfish.
These creatures reproduce asexually and are cylindrical or cone-shaped transparent colonies made up of hundreds of thousands of individuals known as zooids. They were once described by the science journalist Carl Zimmer as a giant “living windsock.”
The volume of water being filtered by each individual zooid gives the colony propulsion mobility, meaning that they can travel great distances. They also glow a blue-green colour, hence the name “pyro” – “fire” in Greek – and “soma” – “body”.
While seemingly harmless, they “consume animals at the base of the food web and lock up that energy. They’re taking energy out of the system that predators need,” said Lisa Crozier, a research scientist at NOAA Fisheries Northwest Fisheries Science Center.
Researchers there have released a report detailing how heatwaves are becoming more severe and frequent in our oceans, meaning the ecosystems are being heavily impacted. In partnership with Oregon State University, NOAA Fisheries examined the food web of the Northern California Current to examine the consequences of heatwaves.
Pyrosomes had not been detected in 25 years of various NOAA surveys until the onset of a heatwave in 2014, Dylan Gomes, co-author of the report, told The Seattle Times.
“They went from being zero – completely absent as far as anybody knows – to being one of the most abundant things in the entire ecosystem,” Gomes said.
The pyrosomes consume plankton, among other things, leaving other marine life without food in the areas where the worms did not live before. If they continue to reproduce at such a rate, they would end up with resources that would kill species including whales.
In fact, as they only consume food, pyrosomes are at the top of the food chain, but they are not classed as prey for predators in the area as they are not killed and eaten by other animals.
Researchers say the study highlights marine heatwaves’ complex and cascading effects on marine ecosystems. While some species may benefit from these changes, others are likely to struggle. Understanding these dynamics is essential for adapting fisheries management practices and protecting marine biodiversity in a warming world.