Micro-boat and a fish inside a jellyfish — October’s best science images

Emerald isles. Eibsee Lake in Germany’s Wetterstein mountains is located 973 metres above sea level, and freezes over every winter. This bird’s-eye view shows how the ice starts to melt at the end of winter, revealing patches of the lake’s emerald-green waters around some of its eight islands. The lake formed at the end of the last Alpine glacial period when a glacier withdrew, and was further shaped by a massive landslide more than 3,000 years ago. The shot was taken by photographer Charlie Berthaume and won third place in the waterscapes category of the 2020 Aerial Photography Awards.

Snail’s tongue. This is the ‘tongue’ — or radula — of a freshwater snail, magnified 40 times. Snails and other gastropods use their radula to scrape the algae that they feed on from rocks and other surfaces — the tiny comb-shaped structures at the edge function like teeth, scraping and cutting the material before it is swallowed. This close-up was taken by molecular biologist Igor Siwanowicz, at the Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Virginia. It has been colour-coded to show depth — the parts that are closest to the camera are bright pink, and the farthest away are blue. The shot won third place in the Nikon Small World 2020 photomicrography competition (see below for a selection of other winning entries).

Swimming shapes. This boat-shaped particle measures just 30 micrometers in length, but is fully equipped with a cabin, chimney and flag post, and is able to propel itself through a solution of 10% hydrogen peroxide. It was 3D printed using a technique called two-photon polymerization, and was then coated with a mixture of platinum and palladium, which catalyses the break-down of the hydrogen peroxide. This reaction produces bubbles of gas that propel the particle along. Daniela Kraft’s team at Leiden University in the Netherlands made many swimming shapes using the same method — including spheres, spirals, triangles and even a miniature starship. They hope that this work will help them to study the effect of shape in microorganisms that swim, such as bacteria.

Surviving extremes. Tardigrades, also known as water bears, are known for being pretty indestructible: they can survive extreme heat, radiation and even the vacuum of outer space. Now, scientists have discovered a species of water bear that can survive intense ultraviolet (UV) radiation. Fluorescent pigments in the tardigrades’ skin appear to convert the UV radiation to harmless blue light, protecting them against UV levels that are regularly used to kill hardy viruses and bacteria.

Mission accomplished! On 13 October, the German research vessel Polarstern returned to its home port in Bremerhaven, ending a year-long international Arctic science expedition. MOSAiC (Multidisciplinary Drifting Observatory for the Study of Arctic Climate), which Polarstern is part of, is one of the biggest research missions ever to go to the Arctic. Last October, the ice-breaker travelled to the Central Arctic Ocean and allowed itself to become trapped in the ice. A rotating cast of scientists and technicians took samples of the ice, atmosphere and ocean, to study the effects of climate change on the Arctic region. In August, shrinking ice allowed the expedition to reach the North Pole. Here, the team gather to release the last radiosonde balloon, which measures variables such as pressure, temperature and humidity in the atmosphere.

Masked monkey. A macaque monkey holds a face mask in Genting Sempah, Malaysia. People worldwide are using masks and gloves to protect against COVID-19. Conservationists warn that use of the items, which are often single-use, could lead to a surge in plastic waste — much of which ends up in the oceans.