Algae within Arctic sea ice provide the lynchpin of the marine ecosystem. As part of an NSF-supported research project, Columbia University scientist Craig Aumack and his colleagues venture out onto the ice to study the organisms that live within, and below, the frozen water — observations that will become even more critical as the Arctic continues to warm. (All images courtesy the National Science Foundation.)
Under the microscope
Researchers run tests to see what kinds of algae harvested critters have been eating. Going forward, the changing climate could mean less snow cover on the ice earlier in the spring, and that could mean disruptions to the food-chain’s delicate balance.
Sea ice algae bloom
Microscopic aquatic organisms form the very base of the marine food web. From single-celled phytoplankton to large macrophytes, such ice-dwelling algae provide structure and environment for fish.
With support from the National Science Foundation, Craig Aumack of Columbia University has come to Alaska with a team to study ice-dwelling algae. As the snow melts in early spring, more and more sunlight causes them to move within the ice column, which is a good indicator that light is heavily controlling their environment and physiological processes. The algae will eventually migrate all the way to the bottom of the ice and enter the water.
The research team consists of scientists, a guide and their bear guard, a trained professional who accompanies the team to protect against bears.
Using drills to create “core units” of ice, the team measures each intact core’s length for ice thickness.
Cutting the ice
At every 10 centimeters, scientists measure each core’s temperature to create a temperature profile. The temperature at the surface is not the temperature down at the sea water. The team is interested in the biological community that lives closest to the water.
The team melts the ice slowly in the lab, a process that takes place between one and four degrees Celsius. A majority, if not all, of the harvested ice-dwelling organisms would suffer from a rapid temperature increase and they could die.
The team collects tiny algae-eaters from the water and underlying mud left exposed after the holes are made to extract the ice cores.
The team is trying to match the algae that grow within the ice to the associated marine system. The algae ecosystem could be considered a “canary in the coal mine” for climate change in the Arctic — early sentinels of a changing environment.
View original article at: Sea Ice Algae is Staple of Arctic Food Chain (Gallery)