“The commentary focuses on the dramatic
environmental changes going on in the Arctic
Ocean in recent decades and how these
changes are affecting local ecosystems.”
Please tell introduce yourself and your area of study.
I am a professor in the Department of Environmental Earth System Science at Stanford University. I am a biological oceanographer, focusing on the study of the role of phytoplankton in the marine carbon and nitrogen cycles. Most of my work has been done in the polar regions of both the Arctic and the Antarctic.
What do you focus on in ‘The changing Arctic Ocean’?
The commentary focuses on the dramatic environmental changes going on in the Arctic Ocean in recent decades and how these changes are affecting local ecosystems. In particular, it documents how the loss of sea ice has altered the magnitude and timing of phytoplankton primary productivity, especially on the shallow continental shelves. It also discusses what the implications of these changes are likely to be for the myriad marine ecosystems that depend on phytoplankton as a source of energy.
In what ways is your research significant to Ocean Science?
Ocean temperatures are increasing globally, but nowhere are these changes as rapid and as extreme as they are in the Arctic (with the possible exception of the Antarctic Peninsula). As such, the Arctic is the bellwether for some of the ecological and biogeochemical changes that may eventually be experienced in other ocean regions as the planet continues to warm..
What kind of fieldwork have you carried out related to your research in the Arctic Ocean?
Members of my research group have been involved in a number of Arctic field campaigns over the past decade, including the Canadian sponsored CASES (Canadian Arctic Shelf Exchange Study) and CFL (Circumpolar Flaw Lead) programs and the US sponsored ICESCAPE program. During these projects, our group was responsible for measuring the physiological responses of phytoplankton to variations in their light environment. These studies are critical in that they to allow us to understand and possibly predict how phytoplankton might respond to future changes in their light environment caused by changes in sea ice cover. Our most important discovery during these expeditions was that phytoplankton can now reach enormous numbers beneath the thinning Arctic ice cover, numbers that rival the most productive phytoplankton blooms anywhere in the world.
Does your research on sea ice have implications for other disciplines?
The ongoing increases in phytoplankton production has implications for disciplines as diverse as ecology, biogeochemistry, fisheries, and even atmospheric science. Because phytoplankton convert carbon dioxide to organic carbon, they reduce surface water concentration of carbon dioxide, increasing the ability of the ocean to take up this important greenhouse gas. Changes in the timing and magnitude of phytoplankton productivity may also impact local fisheries, albeit in ways that are as yet difficult to predict.
What further research do you think needs to be carried out in this specific field? Are there any large bodies of data that you feel are missing?
There are still many unanswered questions related to observed increases in primary production in Arctic waters. How much of this food is being consumed by fish versus sinking to the sea floor and feeding bottom dwelling invertebrates? Is the Arctic becoming a larger sink for atmospheric CO2? How widespread are the large under-ice phytoplankton blooms that were observed in the Chukchi Sea in 2010 and 2011? Why is production in the Arctic increasing everywhere but the Greenland Sea (where it is in decline)? What is controlling primary production in the Arctic, light or nutrients? These questions are of critical importance but are difficult to answer due to the relative inaccessibility of the ice-covered Arctic Ocean. Remote sensing data can help, but much more fieldwork will be necessary to truly understand the changes going on in the Arctic today and expected in the future.
Read Kevin Arrigo’s commentary The changing Arctic Ocean.