Nitrogen supply, uptake, and limits to arctic productivity
Beneath the surface of the Arctic Ocean is a dynamic system that plays an important role in the Earth’s climate. A driver of life in these waters is nitrogen—a key nutrient controlling biological production, which in turn support marine food webs and help absorb carbon dioxide from the atmosphere.
In this lecture, Professor Anya Waite examines how nitrogen is transported from deeper waters into the sunlit surface layer, where it can be used by phytoplankton—the small photosynthetic marine algae that are a key component of the Arctic marine ecosystem.
Professor Waite compares different physical processes—such as mixing, currents, and upwelling—that supply nitrogen, and assess how these relate to observed rates of biological uptake. The results show that physical supply does not always set the limit on productivity; light conditions and biological responses can also be important, sometimes leaving unused nitrogen in surface waters.
Dr. Waite presents a synthesis of current understanding of how physical and biological processes interact, and highlights implications for Arctic marine ecosystems and their role in the climate system.