Plankton 

What is happening and why does it matter?

• Warming can have contradictory and surprising effects on plankton. Increased temperature in the Barents Sea and around Svalbard has led to the presence of more southern species of unknown nutritional value to Arctic feeders. However, rising temperatures in the Chukchi Sea are associated with an increase in the presence of larger fatty copepods.
• There is an unknown, but potential, risk of harmful/toxic phytoplankton blooms. If strong algal blooms become increasingly common in Arctic waters, this could have impacts on seabirds and fish, due to either toxic effects or increased turbidity affecting foraging for visual predators, and fitness in marine mammals.

Why is plankton important?

• Micro plankton (Bacteria, Archaea, microbial eukaryotes and phytoplankton) and zooplankton are the base of the Arctic marine food web, feeding large-sized zooplankton, fishes, seabirds and marine mammals. Changes in these species can have cascading effects throughout the ecosystem and can represent the first sign of overall ecosystem shifts. Despite their importance, plankton are scientifically underappreciated and inadequately known.

What should you know about the monitoring data?

• Particularly unknown elements include the diversity of Bacteria, Archaea, and plankton and their distribution over time and space in the Arctic. This impedes better understanding of Arctic marine ecosystem structure and processes, and thus the ability to apply ecosystem based management.

What are the most important drivers?

• Plankton are strongly affected by climate and differ between open water and ice-cover conditions, current patterns and salinity. Increased open water and less saline surface water could lead to range shifts so that Arctic species become replaced by non-Arctic species, again with unknown consequences for the Arctic marine food web.

Where is monitoring happening?

• Systematic monitoring of phytoplankton and zooplankton has most frequently occurred in Svalbard and Jan Mayen, the Barents Sea, Iceland, Greenland and the southern Bering Sea. Partial monitoring of phytoplankton and zooplankton in Canadian waters has been related to several major research initiatives. The Bering Strait region and northward into the Chukchi Sea have been studied intermittently and inconsistently for nearly a century by the U.S. and Russia, with the southern Bering Sea sampled in recent decades.
• There is no ongoing monitoring for Bacteria and Archaea anywhere in the Arctic.
• Smaller single-celled eukaryotes have been studied using molecular techniques in the Arctic Archipelago, Baffin Bay-Davis Strait, Atlantic Arctic, Pacific Arctic, and Beaufort Arctic Marine Areas.

Advice for monitoring: plankton

• Follow standardized protocols for monitoring plankton, including sample collection and preservation, microscopic and genetic analyses with taxonomic harmonization.
• Ensure that full data sharing occurs between scientists, and is deposited in publicly-accessible national data centers. Continue to consolidate older data.
• Train highly qualified personnel to perform plankton sampling and species-level analyses, including the use of molecular techniques.
• Establish long-term funded annual monitoring programmes of plankton from selected Arctic field stations or Arctic campaigns/cruises in Canada, the United States and Russia, which together with the ongoing monitoring in Greenland, Iceland and Norway will secure a pan-Arctic coverage.
• Develop species indexes and if possible, identify indicator taxa for monitoring.