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Why Some Trees in Norway Are Missing Their Rings

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Dendrochronologists are experts at reading tree rings. They can learn a great deal of information—including past climate in an area and the age of the tree—by taking a tree core sample and reading between the lines (literally).

But as the BBC reports, one climate researcher was stumped when she discovered that many trees in the Norwegian village of Kåfjord were missing their rings. Extreme weather and invasive insects can cause some degree of damage to trees, but not enough to render them ringless.

Claudia Hartl, from Johannes Gutenberg University in Germany, knew that these trees dated back to 1945, but that alone wasn't enough information. Two other clues that helped Hartl and her colleagues solve the mystery were location and history. During World War II, Nazi soldiers moored the Tirpitz—the largest battleship of Hitler's navy—off the waters of Kåfjord to intercept vessels carrying Allied supplies to the Soviet Union. The Germans released an artificial smoke containing chlorosulphuric acid to conceal the ship's location, and this is believed to be the root of the trees' problem.

Artificial smoke could have damaged the needles of the trees, halting the photosynthesis process and stunting the trees' growth, researchers found. It takes time for the trees to recover, but it is possible. One tree saw no growth at all from 1945 to 1954, but after 30 years its growth had returned to normal. Hartl presented the findings at the European Geosciences Union General Assembly in Vienna this week [PDF].

"I think it's really interesting that the effects of one engagement are still evident in the forests of northern Norway more than 70 years later,” Hartl told BBC News. She believes her "warfare dendrochronology" will unearth similar findings elsewhere in the world.

[h/t BBC News]

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Whale Sharks Can Live for More Than a Century, Study Finds
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Some whale sharks alive today have been swimming around since the Gilded Age. The animals—the largest fish in the ocean—can live as long as 130 years, according to a new study in the journal Marine and Freshwater Research. To give you an idea of how long that is, in 1888, Grover Cleveland was finishing up his first presidential term, Thomas Edison had just started selling his first light bulbs, and the U.S. only had 38 states.

To determine whale sharks' longevity, researchers from the Nova Southeastern University in Florida and the Maldives Whale Shark Research Program tracked male sharks around South Ari Atoll in the Maldives over the course of 10 years, calculating their sizes as they came back to the area over and over again. The scientists identified sharks that returned to the atoll every few years by their distinctive spot patterns, estimating their body lengths with lasers, tape, and visually to try to get the most accurate idea of their sizes.

Using these measurements and data on whale shark growth patterns, the researchers were able to determine that male whale sharks tend to reach maturity around 25 years old and live until they’re about 130 years old. During those decades, they reach an average length of 61.7 feet—about as long as a bowling lane.

While whale sharks are known as gentle giants, they’re difficult to study, and scientists still don’t know a ton about them. They’re considered endangered, making any information we can gather about them important. And this is the first time scientists have been able to accurately measure live, swimming whale sharks.

“Up to now, such aging and growth research has required obtaining vertebrae from dead whale sharks and counting growth rings, analogous to counting tree rings, to determine age,” first author Cameron Perry said in a press statement. ”Our work shows that we can obtain age and growth information without relying on dead sharks captured in fisheries. That is a big deal.”

Though whale sharks appear to be quite long-lived, their lifespan is short compared to the Greenland shark's—in 2016, researchers reported they may live for 400 years. 

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Scientists Find a Possible Link Between Beef Jerky and Mania
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Scientist have discovered a surprising new factor that may contribute to mania: meat sticks. As NBC News reports, processed meats containing nitrates, like jerky and some cold cuts, may provoke symptoms of mental illness.

For a new study, published in the journal Molecular Psychiatry, scientists surveyed roughly 1100 people with psychiatric disorders who were admitted into the Sheppard Pratt Health System in Baltimore between 2007 and 2017. They had initially set out to find whether there was any connection between certain infectious diseases and mania, a common symptom of bipolar disorder that can include racing thoughts, intense euphoria, and irritability.

While questioning participants about their diet, the researchers discovered that a significant number of them had eaten cured meats before their manic episodes. Patients who had recently consumed products like salami, jerky, and dried meat sticks were more likely to be hospitalized for mania than subjects in the control group.

The link can be narrowed down to nitrates, which are preservatives added to many types of cured meats. In a later part of the study, rats that were fed nitrate-free jerky acted less hyperactive than those who were given meat with nitrates.

Numerous studies have been published on the risks of consuming foods pumped full of nitrates: The ingredient can lead to the formation of carcinogens, and it can react in the gut in a way that promotes inflammation. It's possible that inflammation from nitrates can trigger mania in people who are already susceptible to it, but scientists aren't sure how this process might work. More research still needs to be done on the relationship between gut health and mental health before people with psychiatric disorders are told to avoid beef jerky altogether.

[h/t NBC News]

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