Stress is a Seaweed Killer
Stress is deadly. It does not only kill humans, but stress can kill seaweed too. This key result was attested by a study conducted by UNSW Australia researchers.
The study revealed that a variety of normally harmless bacteria can cause bleaching disease in seaweed when the seaweeds become stressed by high water temperatures. This simply explains that when seawater plants are stressed, the deadly pathogens proliferate and cause bleaching disease which will eventually led to their demise.
Coral bleaching is a common culprit in the demise of seaweeds. It reduces the ability of the seaweed to photosynthesise and harvest energy from the sun, and to reproduce.
Still baffled for what is causing the bleaching disease, the UNSW Australia researchers spearheaded a probe to particularly identify the pathogens.
The researchers collected samples of healthy and diseased red alga, Delisea pulchra, from about 8 metres under the water at different locations on the Sydney coastline.
Then, the researchers isolated microbes that were dominantly present is the diseased weeds and cultured them. The team of scientists then tested the ability of these microbes to cause bleaching disease in the laboratory.
The result surprised the researchers.
UNSW’s Dr Suhelen Egan, senior author of the study, revealed that they discovered three different kinds of bacteria which are usually present in low numbers on seaweed. These pathogens were identified as members of the Alteromonas, Aquimarina and Agarivorans genera. However, pathogens can all cause the same bleaching disease.
“We also found that the usual balance of microbes was disturbed on the diseased seaweeds, with a lower diversity of microbes present than normal.” – Dr. Egan
With the new discovery, the researchers came up with the assumption that these pathogens are opportunistic in nature where they seize the chance to cause disease when the host is stressed.
Importance of Seaweed
Seaweeds are the “trees” of the ocean. Seaweeds play a major role in marine ecosystems. Marine animals thrive on them for they provide vital habitat, food and shelter for many species of fish and other marine animals, such as crayfish, green sea urchins, lobsters and abalone.