Males of this species may disappear by climate change. Researchers know why

Many organisms do not have sex genes. Whether the animal is a male or female depends on other factors, for example environmental. In the case of oysters, gender depends on the temperature at which the eggs develop – when it is low, the animals take male, and in warm water become females.

These organisms are particularly sensitive to the effects of climate change that can destroy the stability of their population. The study published in the magazine “Environmental Science & Technology” shows that not only oceans warming is a threat to them.

The international team of researchers focused on one parameter – water acidity. As a result of increased carbon dioxide emissions, the oceans absorb it more, creating unstable carbonic acid, weak, but in a high concentration capable of lowering the pH.

Scientists compared the development of Portuguese oysters (Magallana Angulata) In two aquariums – in one water it had a neutral reaction, while in the other it was slightly acidic. The animals from the natural environment have been offspring. As it turned out, in the second generation of oysters living in a sour tank there were more females than males compared to a neutral pH aquarium.

Then the team transplanted second generation oysters to two natural habitats: one with a neutral reaction and one with acidic. In the offspring of animals from a sour reservoir, the higher ratio of females to males occurred in both habitats, while in the descendants of oysters from a neutral aquarium more females appeared only in sour water. This shows that changes caused by acidification can go from generation to generation.

– This is the first study that documents multi -generational development trends caused by exposure to low pH – explained Xin Dang from the University of Hong Kong, the main author of the analysis. – Our results expand knowledge about gender determination in the environment and emphasize the possible influence of global changes on the reproduction and dynamics of the population of mollusks and other marine organisms.

The team also examined the relationship between pH and gender determination through genetic analysis. The results indicated that a number of genes conditioning the development of females joined in response to acidic pH, while a set of genes for males development turned off. Thanks to this, scientists managed to confirm that the environmental reaction has a direct impact on the gender of oysters. Now the research team wants to check whether the acidity of water affects the development of other sea animals in a similar way.