Winged snail

The role of melanin in other pelagic metazoans has been less well studied. Melanie zooplankton are generally rare both in freshwater and marine areas since this would dramatically increase the risk of predation, yet there are some surface dwelling species that may have a conspicuous dark coloration such as some species of Arctic winged snails (opistobranchs) with high levels of melanin (Hessen unpublished). 

Pteropods are a type of plankton also known as winged snails. When pteropods collected from the subarctic Pacific Ocean are kept in water that is less than saturated with aragonite, their shells begin to dissolve within 48 h. Animals such as the pteropod lie at the base of the food chain. Their destruction would reverberate through the entire ocean. 

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