Millions of bizarre blob-like creatures have been washing up on West Coast beaches in recent years due to warming waters caused by climate change.
The gelatinous, transparent mases have been found along the coasts of northern California and Oregon, and sometimes as far as Alaska, but typically live in warm seas – and at great depths.
Now, scientists at Oregon State University found these pyrosomes or ‘sea pickles’ are appearing in droves due to a major marine heatwave that started in 2013 – marking the first time the animals have been seen in 25 years.
Since the proliferation of pyrosomes in the Pacific Ocean, they have also consumed the majority of energy in the sea, causing the number of salmon and seabirds to decline.
Pyrosomes are a gelatinous, blob-like creature that resembles a pink tube with rigid bumps coating its body
Pyrosomes are washing up on the shores of Oregon and Northern California
Pyrosomes feed off phytoplankton which is the basis of marine food webs that provide food for a wide range of sea creatures, but the growing number of sea pickles means there isn’t enough to go around.
These creatures can grow from just a few centimeters up to 60 feet long and resemble a pink tube with rigid bumps coating its body.
Pyrosomes are colonies of thousands of animals called zooids that form in a hollow tube that can grow large enough for a human to fit through.
The marine animals have a gene called luciferase which produces light and when it reacts with the a luminescent chemical, it sends the light up and down the tube, allowing it to see several yards in front of it.
They can also reproduce through asexual reproduction – by effectively cloning themselves – or they can reproduce with a sexual partner.
A new study found that pyrosomes, also called sea pickles, are consuming the majority of the energy in the ocean on the West Coast of the US
Pyrosomes do not provide an adequate food source for other species because 98 percent of their waste ends up on the sea floor
The researchers looked at data across 80 groups of creatures, three nutrient pools, five detritus pools and two fisheries collected since 2014.
‘Pyrosomes consume animals at the base of the food web and lock up that energy,’ said Lisa Crozier, a research scientist at NOAA Fisheries Northwest Fisheries Science Center and co-author of the paper.
‘They’re taking energy out of the system that predators need,’ she added.
Pyrosomes can grow up to 60 feet long and before 2014, hadn’t been seen in 25 years
Pyrosomes are not consumed as frequently as other creatures, like jellyfish, and the study suggests it ‘may be because they are more difficult to digest, offer lower energy content, or remain novel to the food web such that predators have not yet responded.’
According to the study, pyrosomes have long been considered ‘trophic dead ends’ because they can’t serve as an energy source for other species and how nutritious they are for other creatures that have consumed them in recent years remains unclear.
‘That has an impact on the entire ecosystem … the pyrosome is consuming energy that normally would have gone through multiple preys to eventually end up in a salmon,’ co-author of the study Dylan Gomes told The Seattle Times.
Pyrosomes are not consumed as frequently as other creatures, like jellyfish, and the study suggests it ‘may be because they are more difficult to digest, offer lower energy content, or remain novel to the food web such that predators have not yet responded.’
The 2013 marine heatwave, dubbed ‘the Blob’ increased the water temperatures, allowing pyrosomes to thrive while some fisheries closed because salmon, cod and Dungeness crabs declined.
Scientists have speculated if the rising temperatures are to blame because animals’ metabolic rate rises in warmer water and causes them to use more energy.
‘You can think of it as, there’s more consumption for the same amount of seafood being produced,’ Gomes told NewScientist.
Gomes said the study doesn’t incorporate factors that could affect the declining sea life such as the falling oxygen levels caused by the warming waters.
However, he added: ‘It’s a first stab at trying to understand how marine heatwaves are changing the ecosystems of the north-east Pacific.’
The team also compared other marine creatures to the pyrosomes and found that they benefitted the most from the ecosystem while other species like jellyfish, cod, sardines, sea snails and other creatures missed out, causing their population to decrease.
While other creatures like salmon pass on their energy source to feed larger animals, the study suggests that is not the case for pyrosomes where 98 percent of their waste and remains accumulate in the seabed floor – called detritus pools.
