In the past twenty years, global populations of many jellyfish species have increased exceptionally, forcing beach closures, causing power outages, and killing other fish
If you're keeping up with the news, you must already have at least a little idea about the alarming levels of pollution and global warming that we're living with. In fact, scientists recon we're also in the midst of a mass extinction. This is the sixth time in Earth's history that species are experiencing a major global wipe-out in numbers.
Between 500,000 and 1 million plant and animal species face extinction, many within decades, according to a report from the United Nations. Humans are largely to blame for extinction, aside from pollution and warmer weather. Humans contribute to destroying habitats. However, this adverse situation is actually causing the opposite of extinction for a species: Jellyfish.
Jellyfish might seem like a pretty, harmless and insignificant sort, but they've been living in the Earth's oceans for 500 million years. They're found all over the world. There are around four thousand species of them, according to the Smithsonian Institute.
In the past twenty years, global populations of many jellyfish species have increased exceptionally, forcing beach closures, causing power outages, and killing other fish.
According to recent research, this increase can be somewhat attributed to human activity. As greenhouse gases trap heat on the planet, oceans are heating up — they absorb 93% of that excess heat. Unlike many marine species, jellies can thrive in warmer water with less oxygen. Humans are also overfishing and causing a decline in species like turtle and shark, that are jellyfish's natural predators.
Fishing also removes jellies' competition for food; anchovies and squid eat the same type of plankton as jellyfish, so the more those species get removed from the seas, the more plankton jellies can access, according to the Smithsonian Institute.
Jellyfish do not have complex body parts (such as brain, lungs or intestines) and this allows them to adapt easily to changing ocean conditions. They also aren't vulnerable to fluctuating temperature, acidity, and salinity like other marine species, according to JSTOR Daily. So unlike other marine species, ocean pollution isn't affecting them adversely.
In the last 100 years, average ocean surface temperatures have risen by about 1.6 degrees Fahrenheit (0.9 degrees Celsius), according to the National Oceanic and Atmospheric Administration. Last year was the hottest on record for the seas. Warmer waters also mean less oxygen, causing harm to some marine creatures like coral. But in mid-latitudes, in fact, higher water temperatures lead jelly embryos and larvae to develop more quickly, and the animals enjoy longer reproductive periods, according to Inside Climate News.
A 2012 study from the University of British Columbia concluded that "jellyﬁsh populations appear to be increasing in the majority of the world's coastal ecosystems and seas." The study definitively linked this increase to human activity.