Nature (category filter × )

Humans, not climate, have driven rapidly rising mammal extinction rate

gu.se
  • In a new study, researchers found no evidence of climate-driven extinctions in the past 126,000 years—human impact explains 96% of mammal extinctions.
  • The conclusion comes from analysing a data set of fossils from 351 mammal species that have gone extinct.
  • Extinctions happened in bursts that correlated to the time when humans first reached new areas, and recently human-driven extinctions have sped up on a global scale.
  • If current trends in human behaviour and biodiversity loss continue, we might reach a level of extinction 30,000 times larger than natural by the year 2100.
  • To prevent this, we need targeted and efficient conservation strategies, but first people need to become aware of this looming biodiversity crisis.

Microplastic pollution devastating soil species, study finds

theguardian.com
  • Plastic waste in soil is damaging tiny organisms that are essential for recycling carbon and nitrogen, and for breaking down organic matter into food for bacteria.
  • Researchers left different amounts of plastic waste on four areas for 287 days, then collected samples and counted the species found inside.
  • In the most contaminated area, they found that some species declined by as much as 62%.
  • Bacteria and fungi remained largely unaffected, but study authors warn that the effects of microplastics in soil cascade through the soil food webs.
  • The conclusion of the study is that plastic use should be reduced, and burying plastic waste in soil should be avoided.

Why are plants green?

eurekalert.org
  • Researchers created a photosynthesis model based on complex networks (cellphone, brains, power grids).
  • Based on this model, they found that photosynthetic organisms protect themselves from sudden increases in solar energy by absorbing only specific colors of light.
  • Absorbing only parts of the solar spectrum allows them to minimize noise in the output (=generated energy) of their solar cell system.
  • It’s simple physics, it allows these organisms to protect themselves, conserve energy, and - most excitingly - it is consistent with a lot of biological observations.
  • This is the first qualitative proof that photosynthetic beings (like plants) have colors (say, green) in order to protect themselves from absorbing too much energy.

Differentially charged nanoplastics demonstrate distinct accumulation in Arabidopsis thaliana

nature.com
  • Study shows that Arabis (rockcress) can absorb and transport nanoplastics smaller than 200nm.
  • The plant absorbs differently charged nanoplastics in different ways, negatively charged ones being the most internalized.
  • This process can damage roots, and influence how plants transport water and nutrients, making the above-ground parts of the plant smaller.
  • Other plants, especially root crops like carrots and turnips, should be studied for the same process, as they are the foundation of many food chains.
  • Further studies will have to confirm if accumulation of nanoplastics will lead to worse crop yields, worse food quality, or even make common foods unsafe to eat.

Wild Hummingbirds can see colors that humans can’t

inverse.com
  • Seeing more colors gives hummingbirds an advantage when looking for food, mating, and avoiding predators.
  • Human eyes have three color-perceiving cones - red, green, blue, whereas hummingbirds have four cones.
  • The fourth cone multiplies the color-combinations these birds can recognize.
  • To discover this, scientists used a simple reward-based test to see if birds see a difference when spectral colors are enhanced with UV light.

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  • Technology Technology (100) Microwaving plastic waste can generate clean hydrogen
  • Nature Nature (59) Humans, not climate, have driven rapidly rising mammal extinction rate