Warmer ocean temperatures, more ship traffic will open the door for new marine organisms
By Summit Voice
FRISCO — Scientists are warning that warmer ocean temperatures in the far north will open the door for aquatic invaders that could devastate native marine ecosystems.
So far, cold water temperatures have prevented most harmful low latitude species from establishing themselves but the threat of invasive species will grow as the oceans warm and as ship traffic increases in the Arctic, said an international team of researchers led by PhD candidate Chris Ware from the University of Tromsø in Norway.
All in all, the researchers expect a much greater pressure on the marine ecosystems of the Arctic, where fishing is very important for the population in Norway and Greenland.
Specifically, the researchers investigated maritime traffic to Svalbard.
“For the first time we have shown that in the future the port of departure will be more similar to the port of destination in the Arctic than it is today with regard to climate and the environment.” Ware said. “This development will increase the chance of survival for those organisms that could arrive with ballast water or through bio-fouling.”
One example could be the Red king crab, a species that would thrive in the Arctic. This is an example of an animal that could change the balance between the current species, as it would become very dominant in the fragile environment, Ware explained. Other potential invaders are the shore crab, certain tunicates like Didemnum vexillum and the so-called “Japanese skeleton shrimp” (Caprella mutica).
The survey shows that up to one third of the 155 ships that entered the ports of Svalbard during 2011 came from ports that will in the future have an environmental match with Svalbard, thereby increasing the risk that harmful species, which may be brought in as stowaways on ships, will be able to establish themselves.
In 2011 ships that called at Svalbard emptied their ballast tanks 31 times, producing a total volume of 653,000 cubic meters, equivalent to more than 261 Olympic-size swimming pools. Considering each cubic metre of ballast water may contain hundreds of thousands of organisms, billions of organisms can be introduced by ships every year. Slightly more than half of the vessels had replaced the water at sea as required, for example in the North Sea.
By 2050 the climate around Svalbard will be more similar to the climate found in the ports to the south where ships to Svalbard typically depart from. This increases the risk that introduced species will survive and compete with the original species around Svalbard.
In 2100, the number of matching ecoregions will increase to nine, increasing the number of known harmful species with connections to Svalbard more than six-fold.
As a next step, scientists need to determine which stowaways will have the greatest chance to survive the journey in ballast tanks or on the ship hulls, and which are most likely to establish breeding populations after arriving in the Arctic.
A new international ballast water treaty may help slow the spread, but the agreement has yet to be ratified by the United Nation’s International Maritime Organization.