It’s time for our last Summer Q&A!

Are there intertidal animals in Antarctica? Yes there is!

From the left: a bivalve-mollusk a gastropod-mollusk and a flatworm. White scale = 3cm. Photo from Quentin Jossart.

The intertidal (seashore or foreshore) refers to the area emerged at low tide and underwater at high tide. The biodiversity of this zone is well known nearly everywhere in the world, including by kids that love looking after animals under rocks during summer. However, it remains underinvestigated in the Southern Ocean.

The Antarctic intertidal zone is notably characterized by ice-scouring, ice encasement, freshwater input, high UV radiation and important variation in temperature. For a long time, it was thought that these conditions were too extreme to allow the settlement of animal communities. However, some studies surprisingly showed that intertidal communities can establish and persist in Antarctica. Earlier this year, scientists from the Belgica121 expedition evaluated the intertidal diversity in several locations of the Gerlache Strait (Antarctic Peninsula). The biodiversity was investigated using a quadrat approach (small squares randomly disposed at the low tide). The biodiversity was unexpectedly high with 18 different species in average at each site. Three species (a bivalve-mollusk a gastropod-mollusk and a flatworm, see picture below) were very abundant and could reach up to thousands of individuals per square meter. These samples are now back in Belgium where they will be further analyzed (morphologically and genetically). Surely, these intertidal guys are still keeping some secrets.