Sea ice biota

What is happening and why does it matter?

• Ice amphipod abundance has declined around Svalbard since the 1980s, coinciding with declining sea ice conditions.
• It is possible that sea ice algal community structure has changed in the Arctic Basin between the 1980s and 2010s. This uncertainty exists because sea ice extent and thickness declined, but sampling efforts and regions shifted, so it is difficult to attribute change.
• Multiyear sea ice is disappearing and is being replaced by first-year sea ice, which will cause shifts in ice algal communities with cascading effects on the ice-associated ecosystem.
• Seasonal duration of first-year sea ice is becoming shorter, with more snow on the ice, which may decrease the growth season for ice algae, with unknown consequences for biodiversity.

Why is sea ice biota important?

• Sea ice is an important Arctic habitat that supports a rich diversity of species—many of which we know little about. Many different organisms live in and under sea ice, including microbes, single-celled algae, and small multicellular animals. Higher trophic levels are directly or indirectly supported by over 2000 species of small algae and animals that are associated with sea ice, but are often inconspicuous to the naked eye.

What are the most important drivers?

• Sea ice biota are affected by temperature and salinity, nutrient and space limitations and the ephemeral nature of the ice habitat, therefore making them very susceptible to climate change.

What is important to know about the data?

• Changes in sea ice biota are very challenging to detect because sea ice is a dynamic system that has large natural variability, and there has been a lack of consistent sea ice biota monitoring. 

Where is monitoring happening?

• Sea ice biota data have been gathered most frequently in the Arctic Basin, and Atlantic Arctic (Svalbard) and Barrow (Alaska) and the Canadian Arctic, with new sites developing in Greenland.

Advice for monitoring: sea ice biota

• Establish an annual monitoring programme from landfast sea ice at selected Arctic field stations in Canada (Resolute, Cambridge Bay), Greenland (Kobbefjord, Disko Bay, Zackenberg), Norway (Kongsfjorden, Billefjorden, Van Mijenfjorden), and the United States (Barrow).
• Establish a standardized monitoring protocol, including sample collection, preservation, microscopic and genetic analyses, taxonomic harmonization, and data sharing.
• Establish opportunistic monitoring from drifting sea ice during cruises of opportunity.
• Collect macrofauna samples in drifting sea ice via ship-based activities, scuba diving, electrical suction pumps, under-ice trawl nets, and remotely operated vehicles.