Jellyfish And Pollution: Understanding The Impact On Marine Life

Jellyfish have existed for at least 500 million years, outliving the dinosaurs and even trees. They have no brain, eyes, spine, or blood, but they possess a remarkable ability to reproduce and can deliver a powerful sting. Climate change and pollution are now allowing jellyfish to thrive and choke the oceans. Warmer waters and reduced oxygen levels caused by pollution enable jellyfish to reproduce faster and outcompete other marine life, leading to a population boom. This has far-reaching consequences, from disrupting ocean ecosystems to causing power plant shutdowns and beach closures. The increase in jellyfish populations serves as a stark warning about the detrimental effects of pollution and climate change on the health of our oceans.

Jellyfish thrive in polluted waters due to their ability to survive in low-oxygen conditions

Jellyfish have been part of the maritime ecosystem for 500 million years. However, due to their ability to survive in low-oxygen conditions, they are now taking over the oceans, choking them alongside pollution and climate change.

Jellyfish have no brain, eyes, spine, or blood, but they possess a remarkable capacity to reproduce and can deliver a powerful sting. Their propensity to breed fast and prolifically means they can disrupt ocean ecosystems very quickly. Their effects are not limited to the sea, either. Jellyfish blooms have caused shutdowns of power plants in Sweden, Israel, the US, the Philippines, and Japan.

Jellyfish thrive in warmer waters, and their populations are increasing as the climate changes. They also fare better than many other sea creatures in polluted waters, as they can survive in low-oxygen conditions. This gives them an advantage over their predators. They can slip into polluted, low-oxygen waters and hide from predators that require higher oxygen levels, such as fish.

The growth of global jellyfish populations at the expense of other marine life is a warning about the effects of pollution and climate change on ocean health. Jellyfish can survive in areas with lower oxygen levels, where other animals suffer. This is just one factor contributing to their population growth. Overfishing has also depleted the global stocks of some of the jellyfish's natural predators, such as tuna and swordfish, and competitors for food, such as anchovies. With more food and fewer predators, some jellyfish populations can grow unchecked.

Climate change and pollution are causing jellyfish populations to boom

Jellyfish have been part of the maritime ecosystem for around 500 million years. But now, climate change and pollution are causing their populations to boom, allowing them to take over and choke the oceans.

Jellyfish reproduce well in warmer waters, and they can tolerate low-oxygen conditions better than most other sea life. They don't need much oxygen, which means they can hide from predators in polluted, low-oxygen waters. Warmer waters often favour jellyfish growth, but only if they have enough food. So, a warmer ocean will lead to more jellyfish if their food (such as krill larvae, copepods, or fish eggs) also becomes more abundant.

The impact of booming jellyfish populations is being felt on land, too. In places like Sweden, Israel, the US, the Philippines, and Japan, power plants have been affected by blooms of jellyfish. For example, in 2011, an invasion of jellyfish forced the shutdown of both reactors at the Torness nuclear power plant in Scotland. And in 1999, a jellyfish bloom caused a blackout on the island of Luzon, home to the Philippines' capital, Manila.

Jellyfish are also causing problems for fishing and aquaculture industries. For example, in Namibia, overfishing depleted the ecosystem, allowing two species of jellyfish to move in, and their numbers have proliferated so much that fishermen now catch two to three times as many jellyfish as fish. This has had knock-on effects on other animals in the area that rely on fish for food, such as seals and birds, which are reportedly starving due to a lack of fish.

The proliferation of jellyfish is also affecting the largest species, such as the Nomura jellyfish in Japan, which can grow up to 2 metres in size and weigh as much as 200 kilograms. These jellyfish were once seen only every 30 years, but now they're being sighted every year.

Jellyfish mucus can be used to filter microplastics from seawater

Jellyfish mucus could be the answer to tackling microplastic pollution in the world's oceans. The EU-funded GoJelly project is investigating the use of jellyfish mucus as a microplastics filter for commercial and public use.

Microplastics, tiny particles of plastic less than 1mm in size, are a major problem, with more than 150 million tonnes already in the oceans, and up to 12.7 million tonnes added annually. These particles are often not caught by seawater treatment plants due to their small size, and consequently, they enter our systems and harm our health.

Jellyfish mucus has an absorbing property that can catch these microplastics. The mucus can trap the plastics, making them stick to its surface, creating a large blob that is easier to extract and remove. The mucus' intrinsic properties, such as its ability to ensure microplastics adhere to its surface, make it an ideal material for filtering.

The GoJelly project is essentially solving one problem with another. The growing number of jellyfish, called jellyfish blooms, causes disruptions in fisheries, blockages in pipes, and beach shutdowns. By using the jellyfish to create the filters, the number of jellyfish and the problems they cause would drastically decrease. It could also be profitable for fishermen, who could sell the jellyfish they catch to GoJelly.

However, there are some challenges to using jellyfish mucus in this way. There are no standards for microplastic composition in the ocean, and the process of figuring out the required amount of mucus for filtration may be difficult due to the microscopic size of the particles and the vast volume of the ocean. Scaling up the process is another issue, as collecting and extracting mucus from large numbers of jellyfish would be a complex task.

Despite these challenges, the idea of using jellyfish mucus to filter microplastics is an innovative approach to tackling plastic pollution. GoJelly is currently testing various plastic particles and harvesting jellyfish from the sea to develop their biofilters, which will then be demonstrated in the Norwegian, Baltic, and Mediterranean Seas.

Warmer waters often favour jellyfish growth, provided there is enough food

Jellyfish have been around for at least 500 million years, and they're still going strong. In fact, they're thriving as climate change and pollution take their toll on the world's oceans. Warmer waters, in particular, often favour jellyfish growth—but there's a catch. This growth depends on an adequate food supply. So, jellyfish populations will rise with warmer ocean temperatures, but only if their food sources also become more abundant.

Jellyfish feed on other types of plankton, such as krill larvae, copepods, and fish eggs. If their favourite foods become scarce as the ocean warms, jellyfish numbers may actually decline. However, climate change also affects the availability of food for jellyfish. As carbon dioxide levels rise, more carbon dioxide is absorbed by the ocean, leading to ocean acidification. This process inhibits coral growth, causing reefs to die off in a process called coral bleaching. With coral reefs out of the picture, jellyfish have more room to roam and multiply.

The tolerance of jellyfish to low-oxygen conditions also contributes to their success in warmer waters. As ocean temperatures rise, oxygen levels tend to decrease. Some types of jellyfish can handle very low-oxygen environments better than most other types of plankton, so they may be the only surviving ocean animals in these conditions. This advantage allows jellyfish to dominate over other planktonic species.

The impact of warmer waters on jellyfish populations can vary depending on the species and location. For example, the barrel jellyfish in the Mediterranean and Black Seas have benefited from rising temperatures, leading to an increase in their numbers and an expansion of their range. On the other hand, some jellyfish species may struggle in warmer waters if they are unable to adapt or if their food sources become limited.

While jellyfish can take advantage of the changing conditions, the same cannot be said for many other marine organisms. Warmer waters and declining oxygen levels can be detrimental to various fish species, disrupting entire ocean ecosystems. As jellyfish thrive in these altered environments, they can outcompete other species for resources and contribute to the disruption of marine food webs.

Jellyfish can survive in less salty water, which is caused by heavier rainfall

Jellyfish have existed for at least 500 million years—older than dinosaurs and trees. They are brainless, spineless, eyeless, and bloodless, yet they are booming in numbers and causing mayhem around the world. Climate change and pollution are the two main factors contributing to the surge in jellyfish populations. Warmer waters and pollution provide ideal conditions for jellyfish to reproduce and thrive, as they need less oxygen than other sea life.

Pollution and climate change are allowing jellyfish to take over and choke the oceans. One of the consequences of climate change is heavier rainfall. Heavier rainfall affects the salinity of seawater, which in turn affects jellyfish.

Sea surface salinity is influenced by evaporation and precipitation, which force the freshwater balance of the ocean's surface. When precipitation exceeds evaporation, the seawater becomes less salty. Jellyfish can survive in less salty water, which is caused by heavier rainfall.

A study by Mariana Ribas-Ribas and Oliver Wurl investigated the impact of rainfall on sea surface salinity. They found that freshwater from rainfall caused a strong salinity change of up to 6.02 g kg^{-1} in 0–4 cm depth. The salinity anomalies were highest at the sea surface microlayer, reaching a maximum of 14.18 g kg^{-1}.

The study also showed that the absence of wind is crucial in the formation of freshwater lenses, which can last for several hours. In situ observations have shown that surface freshening is proportional to rainfall intensity.

As climate change leads to heavier rainfall, the resulting changes in seawater salinity can provide favourable conditions for jellyfish to survive and thrive, further contributing to their population boom.

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