By: Elin Vinje Jenssen // Norwegian Polar Institute
Over the past twenty years, his visits have become more frequent, enabling him to keep an eye on the effects of global warming on the west side of Spitsbergen. Today, Kongsfjorden at Ny-Ålesund is the most explored fjord in Norway, and perhaps in the world. It is a popular research laboratory for researchers from Norway and abroad.
But what makes scientists flock there?
“Kongsfjorden has a rare mixture of Arctic and Atlantic water and freshwater, as well as sediments that flow out from beneath the glaciers, mainly from the mighty terminus of Kongsbreen glacier,” explains Hop. “The climate has also become considerably warmer over a relatively short period of time, making the ecosystem here particularly interesting for researchers. What happens to life in and around a fjord like this when the temperature changes?”
Kongsfjorden’s water has warmed 2°C
The answers are complex and there are currently more questions than answers. The temperature increase in Kongsfjorden has been rapid. Researchers are working diligently to discern changes in the ecosystem. But the already visible changes are indisputable.
For the last ten to twelve winters, sea ice has been nearly absent from Kongsfjorden, and increasing amounts of warmer Atlantic water have flowed into the fjord. Currently, the water in the fjord is about two degrees warmer than just a few years ago.
“A two-degree increase in ocean temperature is a lot and can affect the ecosystem,” says Hop. “However, with the help of modelling, we have also shown that the ecosystem can adapt to changes observed over more than a decade.”
An ecosystem under a magnifying glass
In the autumn of 2019, Hop released a book describing Kongsfjorden’s ecosystem. In it, he and his long-time collaborator Christian Wiencke from the Alfred Wegener Institute in Germany, expound on Kongsfjorden’s bustling community of algae and animals, and how temperature changes have affected and can affect the organisms that live in and depend on the sea, such as plankton and seabirds. The book also treats physical drivers and processes in the atmosphere and the sea, including hydrography, sea ice and light climate.
“The book highlights all ecological aspects of the Kongsfjorden system, from the marine to the atmospheric environment, including long-term monitoring, the ecophysiology of various species, the ecosystem’s structure and function, ecological processes, and biological communities, both in the water masses and on the seabed,” says Hop.
Temperate species invading the Arctic
Kongsfjorden’s rising temperatures have altered the composition of the biomass found in the fjord. Over the past decades, increasing numbers of Atlantic zooplankton have flowed in from the south and established themselves in the Kongsfjorden system, competing with the more energy-rich Arctic zooplankton species that thrive in colder waters. This can create imbalance and a lack of food in the ecosystem, especially for plankton-eating seabirds like the little auk.
Previously, the little auk has fed on local species of zooplankton, rich in lipids and nutrients. However, the new prey species coming in from the south are smaller and less nutritious. Over time, this can affect the birds’ survival.
“Atlantic zooplankton are smaller and contain less lipids than Arctic zooplankton. The Atlantic species are here in addition to the Arctic species that are already in the fjord. They are still present but may be less numerous than before. Even though the Arctic ecosystem has the ability to maintain and repair itself, extensive changes in the relationship between Arctic and Atlantic species of zooplankton can have major consequences for predators,” says Hop.
International book project
The initiative for the book project The Ecosystem of Kongsfjorden, Svalbard was taken at an international meeting about Kongsfjorden in 2014, which was led by Hop and Wiencke. The participants were asked whether they could write chapters for a book about the ecosystem of Kongsfjorden, and the result has become an extensive work comprising 14 chapters written by a total of 82 authors from 10 countries, many of whom have themselves done research in Kongsfjorden.
The chapters summarise work conducted by researchers from many different institutions. And since the research has been going on for many years, several lengthy time series have been established. The book presents a time series of atmospheric parameters, hydrographic data, sea ice measurements, phytoplankton, and zooplankton.
The book (562 pages) was published by Springer in the series Advances in Polar Ecology.