Current global warming has far-reaching ecological consequences, also for the Earth’s oceans. Many marine organisms are reacting by migrating towards the poles. Researchers at Geozentrum Nordbayern at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have now discovered that marine animals have been migrating for millions of years when the temperature on Earth increases or decreases (https://onlinelibrary.wiley.com/doi/full/10.1111/geb.12732).
Marine animals follow changed temperature zones to the poles or equator
Most living organisms on Earth have settled into ecological niches and one of the decisive factors in their choice of habitat is a certain temperature . Marine animals either need warmer water for their metabolism, such as tropical species, or colder water, such as animals that depend on a higher oxygen content in the water. They therefore migrate either towards the poles or the equator as soon as the temperature changes, and have been doing so for millions of years. ‘Whilst the climate appears to be changing more rapidly today than ever before, the climate also changed rapidly in the past, forcing organisms to migrate in order to survive. Adaptation tended to be the exception,’ emphasises Prof. Wolfgang Kießling, Chair of Palaeoenviromental Research.
By investigating fossils, Prof. Kießling and Dr. Carl Reddin, who is also at GeoZentrum Nordbayern, have shown that coral, molluscs, and sponges have been following their preferred cold and warm zones for half a billion years. Isotherms (geographic lines denoting the same temperature, for example 20°C) shift towards the poles or the equator as soon as the global temperature rises or decreases. Isotherms have been shifting towards the poles for several years due to global warming.
The tendency towards climate-related migration is most apparent in tropical species. This may be due to the fact that several of these species live near the thermal maximum for complex organisms of 35-45°C . Current global warming trends are driving marine animals towards the poles, provided there is a suitable habitat they can migrate to.
Read more at University of Erlangen-Nürnberg
Image: Prof. Dr. Wolfgang Kießling, Chair for Palaeoenviromental Research at FAU (Photo: Carola Radke)