In the freezing waters of the Antarctic there lies a complex and rich ecosystem that has around for millions of years.
Due to recent changes in climate and rising global temperatures, as well as rising seawater temperatures, this might soon change. Not in an abstract, difficult to observe manner, but in the most brutal. The soft-bodied organisms living off the shore of Antarctica are threatened by…king crabs.
Marine worms or sea stars and urchins that have found a home in the Antarctic waters could soon become the prey of the invading shell-crushing king crabs. A new study authored by Professor Richard Aronson of the Florida Institute of Technology explains what this could mean in the Proceedings of National Academy of Sciences.
As water temperatures are constantly rising on the continental shelf off the coast of western Antarctica, conditions become ever more welcoming to a variety of king crab species that have until recently been kept at bay by the prohibitively low temperatures.
King crabs are typically found in the deep waters of the ocean all over the world. They have been spotted in the shallow water of the subpolar regions, but nothing could have predicted the rapid expansion to the deeper waters until recently.
In the Antarctic, water very close to the shore is simply too cold for the king crabs to survive. They can only thrive at temperatures above 1 degree Celsius or 34 degrees Fahrenheit. As we travel the distance from the shallow waters, the temperatures start varying. Just over the continental slope, the temperatures slightly rise just to drop again as the water gets deeper.
It was over the continental shelf that the king crabs have been spotted for the first time. The temperature is sufficiently high for them to form a colony, reproduce and establish themselves in the region for good. Could it have been just a fleeting moment or a random occurrence?
In 2010 Aronson and his research team decided to find out. Through a photographic survey close to the area of the Marguerite Bay, they found out that it wasn’t the case. The colony was already established and counted thousands of individuals of the Paralomis birsteini king crab species.
At the time, they were restricted to the area. So the research team continued to look into the possible factors that could keep the king crabs there or could make them more over in the deeper water of the continental shelf.
It seems that conditions are ripe for the king crabs to make their next move. When this happens, the millions of years old established ecosystem will be severely disrupted.
According to Aronson:
“These prey haven’t experienced this kind of predation in tens of million of years”.
That is to say the soft-bodied organisms here are not equipped and prepared to protect themselves from the invasion of the king crabs. They have no hard shells to keep them from the strong crushing claws, nor any other defense mechanism.
If global warming continues at the current rate, warming the ocean water as well, the king crabs could reach the fragile ecosystem in the Antarctic waters in as much as five years, imprinting a forever lasting change.
Photo Credits: Wikimedia