The Roles of Seasonality, Silicification, and Alteration in Nitrogen and Silicon Isotope Paleo-proxy Variability

Preparing for an expedition to the Southern Ocean is an adventure in itself. You gather your base layers, boots, goggles, socks, and pack your camera and lenses, envisioning the polar environment—one of the most extreme on Earth. Imagine the biting wind on your cheeks and the sight of albatrosses, prions, penguins, humpback whales, and orcas, thriving in such harsh conditions. The excitement is palpable as you prepare to study the microscopic world that sustains this vast ecosystem. Beneath the icy waters lies an invisible world of phytoplankton, microscopic organisms that are the unsung heroes of the marine ecosystem. Despite their size, phytoplankton play a colossal role in maintaining life on Earth.

I thought I had seen all of the colors of blue before my trip to the Far North. After all, I teach about the electromagnetic spectrum and the active and passive sensors that scientists use to understand our changing planet. And yet. There were blues in Kalaallit Nunaat that I had never seen before. While photographs don’t really capture the vibrancy of the colors, or the feeling of being there, they are a starting point for conveying what I mean.

Polar STEAM brought me to Utqiaġvik in collaboration with Dr. Julia York from the University of Illinois. Dr. York’s post-doctoral work is investigating how Arctic fishes, specifically Iqalugaq (Boreogadus saida, Arctic Cod) and Uugaq (Eleginus gracilis, Saffron Cod), physiologically sense and adapt to the freeze thaw cycles that dominate the Arctic throughout the year. Unlike

My whirlwind polar adventure is coming to an end. After a very short 10 days (ALL DAY as the sun has not set in Alaska since mid-May), I find myself spending my last few hours in town reflecting on my experience both with the people as well as the research I helped with, all while admiring the tundra. Polar STEAM brought me to Utqiaġvik in collaboration with Dr. Julia York from the University of Illinois. Dr. York’s post-doctoral work is investigating how Arctic fishes, specifically Iqalugaq (Boreogadus saida, Arctic Cod) and Uugaq (Eleginus gracilis, Saffron Cod), physiologically sense and adapt to the freeze thaw cycles that dominate the Arctic throughout the year. Unlike some of the Antarctic fishes that Dr. York focused on during her PhD, Arctic cod experience a wider range of temperatures throughout the year, from freezing ocean water (28.4°F; -2°C) in the winter to up to mid-40s°F during the summer. Fishes are the same temperature as their environment and environmental temperature fluctuation means that during times of the year fishes must either swim away from the freezing water or adapt mechanisms to keep from freezing.

The US academic research vessel RV Neil Armstrong departed from Nuuk, Greenland in early October. On the first leg of our journey, the science team’s initial purpose was to collect water samples and previously deployed instruments along a line of moorings at the southern entrance to Baffin Bay, a gateway between the Arctic and the north Atlantic. This line stretches from Sisimiut, on the west side of Greenland, to just off Cape Dyer, near the Canadian coast.