The Dawn of the Jellyfish
An ecosystem equilibrium in crisis
The jellyfish has existed for over 500 million years.
With no heart, no brain, no lungs, and no bones. Just muscles and a nervous system. Drifting on the currents of every ocean across the world. Their bodies, made of more than 95% water, have a central mouth which they use to feed on phytoplankton. Some are smaller than the naked eye can see. Others have tentacles longer than a blue whale. Some have stings strong enough to kill a human. Others can go back in time by reversing their own life cycle. Some look like fried eggs. Some glow in the dark. One type of jellyfish is believed to have eyes and can see colours and shapes. Over 2000 species have been identified so far, with possibly thousands more unknown. Who knows what party trick they each might have. Jellyfish have existed for over 500 million years and there’s a good chance they’ll still be here in another 500 million.
As climate change steadily warms the planet, encroaching on the 1.5 degrees tipping point we’re hoping it won't surpass, up to a million species of plants and animals are at risk of extinction. Unless something changes immediately, warming and increasingly acidic oceans, pollution and habitat loss will continue to catastrophically impact the natural world, on an unprecedented scale. And yet, though most living beings will suffer immensely from the effects of climate change, it is a small comfort to know that the jellyfish will not. Jellyfish thrive in warm, fertiliser-rich, deoxygenated ocean water. Must be nice.
They actually enjoy these conditions so much that jellyfish populations have risen in as many as 68 ecosystems around the world since 1950, and counting. There are many positives to an abundance of jellies1 as they provide great services for us and for the oceans. As a mobile-habitat they keep crabs and fish safe from predators within their tentacles. This provides nursery grounds and transportation for any younger and smaller creatures. Their place near the base of the food chain makes them excellent ecosystem engineers and they’re a vital food source for turtles, fish, seabirds and whales.
As the lowly phytoplankton makes up a good portion of a jellyfish’s diet, the carbon these phytoplankton absorb to breathe becomes locked away in a jellyfish's non-existent belly and will sink to the ocean floor when they die. This makes jellyfish great carbon sinks too! In a similar fashion to whales, jellyfish also recycle essential nutrients within the water column and across the seas.
However, it turns out you can have too much of a good thing. While Beached would usually celebrate the success of a marine species and its flourishing, things have been getting a little out of control with the jellyfish. Known as ‘jellyfish blooms’, ocean or wind patterns cause masses of jellyfish to swarm in a certain area. As populations thrive in the warming waters these blooms are getting out of control and have recently led to clogging power plant pipes, causing power outages, overcrowding fishing nets and forcing beach closures.
So how exactly is climate change allowing jellyfish to thrive and why might this be a bad thing?
Recent research has shown that as greenhouse gases heat up the planet, 93% of that excess heat is absorbed by the oceans. This leads to a more acidic and less oxygenated marine space. While most species such as coral reefs cannot survive these rapid changes, jellyfish thrive in the higher temperatures as their embryos and larvae develop more quickly. Faster reproduction rates cause the already prolific jellies to spawn in their millions. The Atlantic sea nettle species of jellyfish could spawn 45,000 eggs per day before the oceans even started warming. There’s also more room for the jellyfish to grow as the coral reefs die off.
Ecosystem disruption on this scale can wipe out entire species from a region. Where jellyfish blooms occur they overfeed, which in turn creates a monoculture within the ecosystem, as plankton as a food source is depleted for other species.
Jellyfish blooms, sometimes referred to as a smack of jellyfish, are also highly destructive as they emerge in their thousands. What was once a rare occurrence now happens frequently across the world affecting tourism, the fisheries sector, overall health and safety and nuclear power plants. In 2018, over a thousand people were stung by jellyfish in one week off the coast of Florida. The UK and Sweden have had to perform costly closures of their nuclear underwater cooling systems as they became blocked by jellyfish swarms. Off Israel’s Mediterranean coast, the blooms threatened to clog up a desalination plant which is used to supplement the country’s water supply. On a salmon farm in the Western Isles of Scotland, 300,000 salmon2 were killed when hundreds of tiny ‘mauve stinger’ jellyfish got inside the cages and significantly reduced the amount of oxygen in the water. Jellyfish swarms spell trouble at the best of times but in these new conditions courtesy of climate change, they are out of control.
It’s important to remember that this is not the jellyfish’s fault. They are just very much enjoying the conditions we’ve been creating for them. It’s not just our burning of fossil fuels that’s giving the jellyfish a helping hand either. As we overfish, killing turtles and sharks in the process, we are removing the jellyfish’s natural predators from the water. Our man-made coastal constructions of harbours, marinas, boat docks and piers are ideal for polyps - think of these as the Queen Bee who stays at home. Polyps permanently attach themselves to hard surfaces and release tiny, juvenile jellyfish who drift away into the open sea. They have a preference for man-made rather than natural surfaces and so the population grows. I’m getting the impression some oil giant, fossil fuel-burning, monoculture farm CEO type has cut a deal with the jellyfish as they also benefit from fertiliser runoff. This occurs when fertiliser from the land enters the water system, eventually making its way to sea. Its properties cause the oversaturation of water with nutrients which leads to an excess of algal growth. As this algal decays it depletes the water of oxygen and you guessed it, the jellyfish love it. Meanwhile the other fish suffocate and die.
So can anything be done?
Well, if jellyfish are thriving off the effects of climate change then maybe we should start there. I won’t repeat what we’ve all heard before but a move away from fossil fuels, eating less meat, and tackling deforestation might just do the trick. In the meantime, we could use this abundance of jellyfish to our advantage.
The GoJelly project, funded by the EU, is developing research which could see the mucus of jellyfish used to bind microplastics. This would act as a filter in wastewater treatment plants and in factories where microplastics are produced. Stopping the tiny particles from getting any further into the water system and out into the oceans and prohibiting microplastics harm to marine ecosystems and wildlife. Another is to use excess jellyfish as fertiliser for aquaculture feeds. Fish farms are currently fed with captured wild fish which only worsens the overfishing issue. This method would “be much more sustainable and protect the natural fish stocks”. Jellyfish can be used for medicinal purposes too - one of their proteins can be used to detect toxins in human cells.
As it stands, a warming ocean will lead to ever more jellyfish. As long as their food source survives there’s no slowing them down just yet.
Control the jellyfish. Save the oceans.
Here at Beached we are building a community that can put our brains and resources together to highlight and fund solutions to the problems facing jellyfish and the oceans they live in. I hope you’ll join our humble community and click subscribe for free or support our work by purchasing the paid subscription.
All Beached posts are free to read but if you can we ask you to support our work through a paid subscription. These directly support the work of Beached and allow us to engage in more conversations with experts in the field of marine conservation and spend more time researching a wider breadth of topics for the newsletters. Paid subscriptions allow us to dedicate more time and effort to creating a community and provide the space for stakeholders to come together, stay abreast of each other’s work and foster improved collaboration and coordination.
One day Beached hope to donate a large percentage of the revenue from paid subscriptions to marine conservation organisations and charities to support their work too. Working together, we can reverse the degradation of our oceans.
Amie 🐋
Besides how delicious they are with ice cream.
Worth £1 million.