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Giant Jellyfish | Earth Wise

August 28, 2020 By EarthWise Leave a Comment

There have been recent news stories about giant jellyfish washing ashore from Maine to the south coast of Massachusetts. These stories have claimed that some of these lion’s mane jellyfish have been the largest on record and even might be the largest animals in the ocean.

The truth of these accounts is rather suspect. For one thing, it is rather difficult to measure the size of a jellyfish when it is out of the water. Gravity compresses and spreads out the bell portion of the animal, and that makes up the bulk of its mass. For example, a jellyfish bell that measures four feet across on the beach would appear to be much smaller if the animal was floating in the water.

Some claims that lion’s mane jellyfish are larger than blue whales date back a full century and are very much disputable. The claimed size certainly included the animal’s long tentacles, and such things hardly compare with a blue whale.

In any event, the current spate of jellyfish sightings is not necessarily that unusual. Many factors influence jellyfish populations, including water temperature and food supply. It is possible that warming water temperatures may be influencing the jellyfish population this year, but there is not enough data to know for sure.

People do need to be cautious around lion’s mane jellyfish. They do sting and while their stings are not as bad as those of a number of other species, they can be a problem for people who have allergic reactions. Furthermore, the stinging cells remain active in a jellyfish that has washed ashore.

Sightings of these animals are continuing, and reports of larger specimens continue as well, even if they don’t compare with blue whales.

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Jellyfish larger than blue whales?

Photo, posted September 13, 2015, courtesy Derek Keats via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bad News For Penguins

June 21, 2019 By EarthWise Leave a Comment

The second-largest breeding colony of emperor penguins in Antarctica, located in the Waddell Sea, has experienced “catastrophic breeding failure” for the past three years. Nearly all of the colony’s chicks have failed to survive due to the breakup of sea ice, according to a new study published in the journal Antarctic Science.

The colony was once home to 14,000 to 25,000 breeding pairs, which represents as much as 9% of the global emperor penguin population. Emperor penguins are the tallest and heaviest of all living penguins, reaching up to 4 feet in height and weighing between 50 and 100 pounds. They are the only penguin species that breeds during the Antarctic winter and their lengthy treks to breeding colonies have been the subject of numerous films and television shows.

Sea ice at Halley Bay in Antarctica had been stable and reliable for nearly 60 years but stormy weather in 2016 driven by El Nino conditions, strong winds, and record low ice extent caused the ice on which penguin chicks gather to break up. This happened again in 2017 and 2018. By last year, just a few hundred adult pairs were present at the breeding site and almost no chicks survived the ice breakup.

Researchers say that they have never seen a breeding failure on a scale like this in 60 years of studying the colonies. On a more positive note, while the population of the Halley Bay site has collapsed, the Dawson-Lambton breeding area – located about 34 miles away – has actually seen significant growth over the past four years. While this is encouraging, the growth at Dawson-Lambton does not fully compensate for the losses at Halley Bay, which was once considered relatively safe from the impacts of climate change.

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Emperor Penguin Colony Experiences “Catastrophic Breeding Failure”

Photo, posted February 22, 2011, courtesy of Krishna via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Is There Hope For Coral Reefs?

January 16, 2019 By EarthWise Leave a Comment

News about the world’s coral reefs has been relentlessly bad for a number of years. Warming, acidifying oceans have wreaked havoc with coral reefs leading to enormous losses. Nowhere have things been more dire than in Australia’s Great Barrier Reef. Coral bleaching events have been increasingly common and severe over the past two decades. In fact, only 7% of the Great Barrier Reef has escaped bleaching entirely since 1998.

While the future of the world’s coral reefs is very much uncertain as global heating continues, there is a recent bit of hopeful news. According to a study published in Nature Climate Change, the response of the Great Barrier Reef to the extreme temperatures in 2017 was quite different from that of the previous year in the aftermath of back-to-back bouts of coral bleaching.

Surprisingly, corals that bleached in 2016 but managed to survive were more resistant to the recurrence of hot conditions in 2017.

Many corals don’t survive bleaching events at all and, of course,those corals don’t bleach for a second time. But the surviving corals from the 2016 bleaching event were tougher species. As a result of bleaching, the mix of coral species on the reef is changing very rapidly. The net result was that there was less bleaching in 2017 even though the temperatures that year were even more extreme than in 2016.

There have now been four mass bleaching events on the Great Barrier Reef over the past 20 years and it is only a matter of time before another one occurs triggered by the next marine heatwave. Almost half of the corals on the northern two-thirds of the reef have been killed. But at least some of the reef is showing impressive survival skills.

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