The effects of climatic change alter the regeneration of marine worms

José Pichel Andrés/DICYT Researchers of the Centre of Environmental and Marine Studies (Centro de Estudos do Ambiente e do Mar, CESAM) of the University of Aveiro have found by experiments that the acidification of the sea, the drop in salinity, or the temperature alter the regeneration capacity of the species Diopatra neapolitana, a worm that may grow to over 30 centimetres in length.

The researchers chose Diopatra neapolitana because of its commercial interest as it is used as fishing bait and also because of its ecological importance as a source of food for many fish and crustaceans, as the CESAM researcher Adília Pires explained to DiCYT. Moreover, this species is widely distributed all over Europe from the Atlantic coast of France to the Mediterranean, which makes its study of great interest.

In order to carry out the experiments, the scientists cut part of these organisms and placed them in glass aquariums to find out how they regenerated their rear ends. Every so often they measured the worms under different conditions of acidity, salinity, and temperature.

The most important results were reflected in an article published in Marine Environmental Research and indicate that a reduction in the pH of the sea (greater acidity) and sudden changes in salinity mean that this polychaete needs more days to complete the regeneration. On the contrary, if the temperature increases the regeneration is faster.

Climatic change forecasts indicate that all these factors can occur together, both the changes in the pH and the salinity that hinder regeneration and the increase in temperature that accelerates it. However, the scientists are not so sure that some circumstances compensate for others. “It is important to study the combined effects of temperature and salinity, because we do not know which of the two conditions has the strongest impact”, the expert comments.

In any case, this area of research “can help us to understand the possible consequences of climatic change”. The delay in regeneration would have negative consequences for the reproduction of the species, and this could jeopardise its conservation in the near future according to the specialists of the University of Aveiro.

“Some species are capable of adapting well to climatic change, while other more sensitive ones are seriously affected. In the case of D. neapolitana further study is necessary to confirm the situation, although it could be capable of adapting unless the salinity is very low”, the researcher points out.

Effect on the food chain

In any case, if climatic change can reduce the numbers of some species considerably, the consequences will be felt all through the food chain. This may mean that some species not directly affected will be left without a source of food and will have to find it elsewhere.

Although this research by Adília Pires has concentrated on polychaetes and their sensitivity to climatic change, it also analyses how other alterations affect these animals, such as contaminating products that end up in the sea. Among other aspects, she has found that contamination by pharmaceutical products also modifies the regeneration capacity of these organisms and alters their cells.

	Bibliographical reference
	The effects of water acidification, temperature and salinity on the regenerative capacity of the polychaete Diopatra neapolitana. Adília Pires, Etelvina Figueira, Anthony Moreira, Amadeu M.V.M. Soares, Rosa Freitas. Marine Environmental Research, Volume 106, May 2015, Pages 30–41.