Apr 12: How human noises impact animals, and more...
Tree harnesses lightning, anti-anxiety meds affecting salmon, Denisovan jawbone and Earth's smushy inner core
On this week's episode of Quirks & Quarks with Bob McDonald:
Scientists working in Panama noticed that a particular tropical tree species was frequently struck by lightning, but was infrequently killed by the strikes. Forest ecologist Evan Gora found that Dipteryx oleifera trees were often the last ones standing after a lightning strike, which can kill over 100 trees with a single bolt. His team discovered the giant trees were more electrically conductive than other species, which allows them to not only survive strikes, but also channel lightning into parasitic vines and competing trees around them. The research was published in the journal New Phytologist.
Our bodies only process some of the pharmaceuticals we take, which means when we pee, we're releasing traces of drugs into the ecosystem. A study of the impact of trace amounts of anti-anxiety drugs on juvenile salmon suggests they might become too brave for their own survival. Jack Brand is a researcher at the Swedish University of Agricultural Sciences and led the research published in the journal Science.
A jawbone pulled up by fishers off the coast of Taiwan in 2008 has proven to be a unique discovery. Analysis of preserved protein in the fossil has proved it is from a male Denisovan — a mysterious species of ancient human known from only fragmentary bones and ancient DNA. This gives new insight into how widespread this mysterious branch of humanity was. The research was led by a team including Takumi Tsutaya and Enrico Cappellini at the University of Copenhagen, and published in the journal Science.
Scientists used to think the inner core of our planet was a solid sphere of metal, but a new study in Nature Geoscience suggests its softer outer layers shift and deform over time. The researchers used pairs of earthquakes from the same location as X-rays to peer inside Earth to gauge what the inner core is doing; much like a stop-motion film. John Vidale, from the University of Southern California, said this insight can shed light on how a planet like ours evolves.
Traffic, aircraft, industry, construction. Our world is saturated with artificial noise. We know noise impacts us and other animals, but new research is shedding light on how past experiences factor into the ways wildlife adapt to our noise pollution.
Researchers in one study in Animal Behaviour found that yellow warblers in the Galapagos Islands that live closer to traffic become aggressive when defending their territory in noisy conditions compared to birds in quieter areas. Çağlar Akçay, from Anglia Ruskin University, said the birds exposed to more traffic have learned their warning calls aren't as effective when things get too noisy; and they resort to physical violence.
Another study in Current Biology shows how spiders that are exposed to loud noises construct their webs differently in ways that could affect their ability to sense vibrations from prey or a potential mate. Brandi Pessman, from the University of Nebraska-Lincoln, found that spiders tune their webs in noisy environments like a volume dial: city spiders turn their web volume down whereas country spiders turn it up.
