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Tiny Plastics in the Ocean Are Harming Baby Fish

Plastic pollution in our world’s oceans might carry more dire consequences than we initially realized. According to a new study published in the journal Science, some baby fish like to chow down on plastic microparticles instead of natural foods like free-swimming zooplankton. In turn, this unnatural diet leads to stunted growth, changed behavior, and, ultimately, increased mortality rates, the BBC reports.

Researchers from Uppsala University in Sweden collected fertilized European perch eggs and embryos from the Baltic Sea. They then exposed them to different concentrations of polystyrene plastic microparticles that were smaller than one-fifth of an inch, around the size of ones floating in the sea.

When the eggs weren’t exposed to microplastics, 96 percent of them hatched. But when they were exposed to high concentrations of the plastics, the amount dropped to 81 percent. Meanwhile, the surviving fish that had been exposed to the plastic were reportedly “smaller, slower, and more stupid,” the study’s lead author, Oona Lönnstedt, told the BBC.

The fish also didn’t fare well against predators as their olfactory responses were impaired. Within 24 hours, larger fish like pike had gobbled up all the fish that had been raised with high plastic concentrations. In comparison, half the fish from clean waters survived.

Perhaps most strikingly, fish larvae that had access to the plastic particles preferred to eat them instead of zooplankton. “This is the first time an animal has been found to preferentially feed on plastic particles and is cause for concern,” Peter Eklöv, the study’s co-author, said in a press statement.

Researchers plan to research the perch in their natural setting, and study how exposure to other plastic contaminants affects development. “Now we know that polystyrene is harmful, but we also need to compare it to the other common polymers such as polyethylene and PVC,” Lönnstedt told PBS NewsHour. “If we can target the chemical that is most harmful, at least this could hopefully be phased out of production.”

While President Obama signed a ban on plastic microbeads last year, some 13 million tons of plastic reportedly flows into the sea each year, and experts say that amount will only increase. Meanwhile, according to PBS NewsHour, up to 236,000 metric tons of microplastics enter the oceans each year thanks to larger pieces of plastic breaking down into little pieces.

[h/t BBC News]

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NUS Environmental Research Institute, Subnero
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technology
Researchers in Singapore Deploy Robot Swans to Test Water Quality
NUS Environmental Research Institute, Subnero
NUS Environmental Research Institute, Subnero

There's something peculiar about the new swans floating around reservoirs in Singapore. They drift across the water like normal birds, but upon closer inspection, onlookers will find they're not birds at all: They're cleverly disguised robots designed to test the quality of the city's water.

As Dezeen reports, the high-tech waterfowl, dubbed NUSwan (New Smart Water Assessment Network), are the work of researchers at the National University of Singapore [PDF]. The team invented the devices as a way to tackle the challenges of maintaining an urban water source. "Water bodies are exposed to varying sources of pollutants from urban run-offs and industries," they write in a statement. "Several methods and protocols in monitoring pollutants are already in place. However, the boundaries of extensive assessment for the water bodies are limited by labor intensive and resource exhaustive methods."

By building water assessment technology into a plastic swan, they're able to analyze the quality of the reservoirs cheaply and discreetly. Sensors on the robots' undersides measure factors like dissolved oxygen and chlorophyll levels. The swans wirelessly transmit whatever data they collect to the command center on land, and based on what they send, human pilots can remotely tweak the robots' performance in real time. The hope is that the simple, adaptable technology will allow researchers to take smarter samples and better understand the impact of the reservoir's micro-ecosystem on water quality.

Man placing robotic swan in water.
NUS Environmental Research Institute, Subnero

This isn't the first time humans have used robots disguised as animals as tools for studying nature. Check out this clip from the BBC series Spy in the Wild for an idea of just how realistic these robots can get.

[h/t Dezeen]

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iStock
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science
There May Be an Ancient Reason Why Your Dog Eats Poop
iStock
iStock

Dogs aren't known for their picky taste in food, but some pups go beyond the normal trash hunting and start rooting around in poop, whether it be their own or a friend's. Just why dogs exhibit this behavior is a scientific mystery. Only some dogs do it, and researchers aren't quite sure where the impulse comes from. But if your dog is a poop eater, it's nearly impossible to steer them away from their favorite feces.

A new study in the journal Veterinary Medicine and Science, spotted by The Washington Post, presents a new theory for what scientists call "canine conspecific coprophagy," or dogs eating dog poop.

In online surveys about domestic dogs' poop-eating habits completed by thousands of pet owners, the researchers found no link between eating poop and a dog's sex, house training, compulsive behavior, or the style of mothering they received as puppies. However, they did find one common link between the poop eaters. Most tended to eat only poop that was less than two days old. According to their data, 85 percent of poop-eaters only go for the fresh stuff.

That timeline is important because it tracks with the lifespan of parasites. And this led the researchers to the following hypothesis: that eating poop is a holdover behavior from domestic dogs' ancestors, who may have had a decent reason to tuck into their friends' poop.

Since their poop has a high chance of containing intestinal parasites, wolves poop far from their dens. But if a sick wolf doesn't quite make it out of the den in time, they might do their business too close to home. A healthier wolf might eat this poop, but the parasite eggs wouldn't have hatched within the first day or two of the feces being dropped. Thus, the healthy wolf would carry the risk of infection away from the den, depositing the eggs they had consumed away in their own, subsequent bowel movements at an appropriate distance before the eggs had the chance to hatch into larvae and transmit the parasite to the pack.

Domestic dogs may just be enacting this behavior instinctively—only for them, there isn't as much danger of them picking up a parasite at home. However, the theory isn't foolproof. The surveys also found that so-called "greedy eaters" were more likely to eat feces than dogs who aren't quite so intense about food. So yes, it could still be about a poop-loving palate.

But really, it's much more pleasant to think about the behavior as a parasite-protection measure than our best pals foraging for a delicious fecal snack. 

[h/t The Washington Post]

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