Satellite images show how penguins' diets are changing in response to Antarctic climate change

Satellite images of Adélie penguin guano are giving scientists a new way to monitor Antarctica’s changing climate and its effects on the marine food web. Researchers led a multidisciplinary study using thousands of Landsat satellite images dating back to the 1980s, when large colonies of the birds produced guano patches identifiable from space. They found that colonies with abundant sea ice tended to rely more on small fish, while areas with less sea ice saw greater dependence on krill. Pinker guano helps track diet because krill has a pink exoskeleton that contributes to a rosy tint after partial digestion. The work analyzed around 4,000 images and related guano color to diet using ship-based sampling and spectrometry.