The balance of the Pacific and Atlantic Oceans
ecosystems along the coast might soon be tilted in an unknown direction due to
a new threat, which is killing off thousands of its starfish, known as Sea Star
Wasting Syndrome. Sea Star Wasting Syndrome is the new marine disease so
devastating it has an estimated mortality rate on infected starfish of
ninety-five percent and it already affects over twenty species on the U.S. coasts.
This horrific disease causes starfish to lose entire limbs in a matter of days
leading to their inevitable death. The symptoms are well known by marine
biologists, but the actual pathogen causing the disease is not. High mortality
rates of sea stars are significant to the entire ecosystem of the species since
they are a keystone predator of many crustaceans and Mollusca. First let us
look at the symptoms of Sea Star Wasting Syndrome to grasp an understanding of
its severity.
Courtesy USCS Long Marine Lab
Marine
biologists, studying sea stars with the disease, describe the main symptom of
the syndrome to be, sea stars tearing themselves apart which is a good
interpretation of the disease in a nutshell. The disease first causes white
lesions in the ectoderm of the sea star on the body or a single limb, the
initial lesion may then spread to other areas of the organism. The sea stars
tissue begins to deteriorate around these lesions. Finally, the sea star begins
to fall apart around the lesions due to the surrounding deterioration of tissue.
The fragmentation is what leads the sea star to death, but the actual pathogen
causing the disease is still a mystery.Source 1
The first documentation of sea star syndrome was in
the summer of 2013 and the exact pathogen causing the disease has not been
found yet. Scientists have come to the assumption that: recent increase in
temperatures are aiding the pathogens infection rate by putting sea stars under
abnormal stress. This assumption is based off the fact that most of the first
infected species were in the warmest of water, like intertidal zones. Now
scientists have spotted signs of infection in colder waters and swift currents
in areas such as the Washington’s San Juan Island. San Juan Island has only
recently experienced the infection do to the rise in temperatures of its waters
during the summer, the islands are usually cooler than the adjacent continent.
This assumption that warm waters is aiding to the rise of the infection seems
to be fairly correct but, the actual pathogen is still a mystery. Scientists
believe that the pathogen is a bacteria or virus but do not know which, even
though the first documentation was over a year ago. Source 2
Credit: Melissa Miner
Sea Stars are
keystone species to many oceanic ecosystems, meaning it has a tremendous effect
on the ecosystem relative to the size of its population. Keystone species, such
as many sea star species, have a critical role in maintaining balance in their
ecosystem. Sea stars are keystone predator that feed on Mollusca and
crustaceans, and since there are many different types of Mollusca and
crustaceans for sea stars to feed on there was a high abundance in sea stars.
Now that sea stars are becoming less common, some species in California and
Florida are on the verge of extinction, there are many more of these Mollusca
and crustaceans. Scientists are skeptical on just how the ecosystem will
change, but my prediction is that there will be an increase of grazing like
organisms like snails, which are easy prey for sea stars, and subsequently a
decrease in algae. I believe that the overpopulation of these grazers will lead
to a decrease in oxygen levels in the ocean and increase carbon dioxide levels.
What this means exactly I am not very sure, but hopefully a solution can be
found (or a mutation to arise) to reset the balance in the effected ecosystems.
Further Study:
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