A recent study suggests that the Arctic Ocean is much more active at night than scientists previously thought – here’s why.
The oceans at the poles are cold. Really cold. You might imagine that it would be extremely difficult for anything to live in water that is on the verge of becoming ice, but a new study suggests that this assumption would be totally wrong. According to a press release from Eurekalert, researchers working in the Arctic Ocean have discovered a wide range of activity in the waters off of Kongsfjorden, Svalbard off the coast of Norway.
The study was published in the September 24 edition of Current Biology by researchers from the Arctic University of Norway and the University Centre in Svalbard.
According to lead researcher Jorgen Berge of the Arctic University of Norway, “This once and for all changes the way we think of marine ecosystems during the polar night.”
Researchers long believed that there was little activity under the cover of darkness in the Arctic Ocean, but a wide range of different species live in the depths to create a bizarre, beautiful, and active ecosystem.
Berge said that the researchers wanted to get a better sense of what happens in the Arctic Ocean as night falls each day. The idea for the study came to the researchers as they were finishing up some fieldwork in a small boat in the middle of a fjord in Svalbard. Below the starry sky in the dead of winter, bioluminescent organisms put on a stunning display of green and blue light from below the surface of the water. The intensity of the light show was too much to be a part of a small, bare-bones ecosystem. In order for these organisms to exist, they had to be supported by a full-blown ecosystem that supported many different trophic levels. Clearly, life did not take time to hibernate in the cold Arctic winters.
Berge decided to carry out a large-scale study of the creatures that lived in the fjords of the Arctic Circle, with a particular focus on nighttime activity. He studied a location in a Svalbard fjord for three consecutive winters, and was shocked at what he found. Underneath the surface of an ocean believed to be asleep, Berge’s research team discovered an ecosystem with staggering biodiversity below the darkness. In fact, some species even seemed to be taking the cold water as a sign to kick reproduction into high gear, producing more offspring that during the warmer months of the year.
The first thing the team noticed was copepods and other zooplankton in a flurry of reproductive activity. The rich plankton population serves as the basis for a complex food web, which included sea scallops that filtered the tiny organisms directly out of the water. They set up cameras to record activity from other mobile creatures, and found a bustling community of scavengers of the shallows, including amphipods, whelks, and crabs.
One of the most surprising finds throughout the study, however, were the seabirds. We don’t think of seagulls as being the brightest marine animals, but the waterfowl in the Arctic Ocean were able to hunt for their favorite foods in complete darkness during the cold Arctic nights. “We do not know how they are able to do this, and we do not know how common it is for seabirds to overwinter at these latitudes. But we no know that they do,” Berge said.
At a time when climate change is causing the Arctic to undergo a rapid transformation, it is surprising that scientists didn’t know more about the wildlife in this region. As the water surrounding the Arctic Circle warms and ice cover melts, species from lower latitudes are likely to travel north in search of cooler temperatures and will inevitably alter the ecosystem described in the study.
Climate change stands to bring a wide range of new activity to the Arctic, including increased production of fossil fuels, a larger fleet of fishing boats and more tourists. Berge warns, “We can’t simply assume that the dark polar night is a ‘safe’ period when things are not turned on.” The stunning biodiversity discovered in this small study indicates that we know very little about the Arctic, and we know even less about how it will change over time.
The dark nights of the winter may prove to be an extremely important time for life in the Arctic Ocean. Plankton use this time to reproduce, which in turn provides a food source for animals throughout all trophic levels. The study was funded by the Norwegian Research Council, and Berge hopes he can continue to research the creatures of the Arctic deep in the near future.