Though many people still deny there is any climate change, effects of global warming can be observed all across the planet. The latest confirmed victim of rising temperature is starfish.
According to new research, starfish are going through sea star wasting disease (SSWD). The study suggests they could be in respiratory distress where they “drown” in their habitat. While the obvious question is how can a sea creature drown, the answer lies in their breathing mechanism.
One of the scientists from Cornell University, Microbiology professor Ian Hewson explains how these ancient creatures breathe. The sea dwellers have structures known as papulae, or skin gills, on their body surface. Through these structures, they diffuse oxygen into their body. “If there is not enough oxygen surrounding the papulae, the starfish can’t breathe,” Hewson explains in a statement published on the Cornell University website.
As the temperature rises on the ocean floor, microbial activity increases facilitated by proximate organic matter. More microbes (i.e. bacteria) mean more consumption of oxygen. As they deplete the already low-oxygen environment of the life-affirming gas, starfish fall prey to diseases and result in puffiness deflation and limb curling or twisting, discolouration, and so on.
This condition has been observed for the past seven years and has threatened the extinction of a few species. Initially, the SSWD mystified the experts but they finally know the cause of this sudden illness among these echinoderms.
Starfish are very important ecological members of marine life and are keystone species in many areas. A keystone species is a group of animals or plants which has a magnificent impact on their ecology. Erasure of any keystone animal/plant can result in excessive ecological malfunction.
“It’s organic matter concentrations in the water. If you have a dead and rotting starfish next to starfish that are healthy, all of that dead one’s organic matter drifts and fuels the bacteria, creating a hypoxic environment. It looks like disease is being transmitted,” Hewson added. The main culprit in this scenario are copiotrophs; a group of bacteria which survive on carbon and organic matter.
The author claims this discovery means the sea-experts need to change their outlook on oceanic diseases which is mostly focused on pathogenic microbes – disease-causing bacteria and virus. He suggests that researchers should now include microorganisms that are directly pathogenic in nature but still play a vital role in marine health and sea star diseases.
“It’s a cascade of problems that starts with changes in the environment,” Hewson said. The study can be found in the journal Frontiers in Microbiology as “Evidence That Microorganisms at the Animal-Water Interface Drive Sea Star Wasting Disease.”