Stored heat may melt ice 

• The Arctic ice cap isn't threatened just by melting ice around its edges, warmer water that originated hundreds of kilometres away has also penetrated deep into the Arctic Ocean. This "archived" heat, currently trapped below the surface, can melt all the sea ice if it reaches the surface, researchers report in the journal, Science Advances. The upper ocean in the Canadian Basin, for example, has seen a two-fold increase in heat content over the past 30 years, with its source hundreds of miles south. Arctic winds are driving the warmer water north, but keeping it below the surface.

Pollen eater 

• We know bees and butterflies as proficient pollinators but millions of years before them, beetles were the pre-eminent pollinators. Among the prehistoric plants they helped fertilise were cycads - which look like a cross between a palm and a fern but are actually related to pine trees. In a recent article in Current Biology, palaeontologists have reported that they have found a 99-million-year-old beetle, along with pilfered cycad pollen, trapped in amber mined in Myanmar.

Marimo light 

• Marimo is the Japanese name for a ball formed of a colony of algae in a freshwater lake. Biologists at the University of Bristol, UK, have found that these balls rise to the surface during the day as the algae regulate photosynthesis with a biological clock and, in the process, release oxygen bubbles that carry them toward the sun.

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