A study into marine life around an underwater volcanic vent in the Mediterranean, may hold the key to understanding how some species will be able to survive the acidifying of sea water should anthropogenic climate change continue.
Researchers found that some species of polychaete worms are able to modify their metabolic rates to better cope with and thrive in waters high in carbon dioxide (CO2), which is otherwise poisonous to other, often closely-related species.
The study sheds new light on the robustness of some marine species and the relative resilience of marine biodiversity should atmospheric carbon dioxide continue to cause ocean acidification.
A team of scientists led by Plymouth University, and including colleagues from the Naples Zoological Station in Ischia; the Marine Ecology Laboratory ENEA in La Spezia, Italy; the University of Texas Galveston; and the University of Hull, conducted a three-year research project into the potential mechanisms that species of worm polychaetes use to live around the underwater CO2 vent of Ischia in Southern Italy.
The researchers collected specimens found in waters characterised by either elevated or low levels of CO2, and placed them in specially-constructed ‘transplantation chambers’, which were then lowered into areas both within and away from the volcanic vent. They monitored the responses of the worms and found that one of the species that had been living inside the CO2 vent was physiologically and genetically adapted to the acidic conditions, whilst another was able to survive inside the vent by adjusting its metabolism.
The results revealed that species normally found inside the CO2 vent were better able to regulate their metabolic rate when exposed to high CO2 conditions, whilst species only found outside the CO2 vent were clearly impaired by acidic waters.
In fact, their metabolism either greatly decreased, indicating reduced energy production, or greatly increased, indicating a surge in the basic cost of living, in both cases making life inside the vent unsustainable.
The team also found that those species adapted to live inside the CO2 vent showed slightly higher metabolic rates and were much smaller in size – up to 80 percent smaller – indicating that adaptation came at a cost of energy for growth.
The findings have been published online in the Philosophical Transactions of the Royal Society B.