Climatic and tectonic factors created the current distribution of coral reefs in the tropics

Changes in past climate and the distribution of shallow water habitat have shaped the current distribution of coral reefs. This is the main conclusion of the international study carried out by the researcher at the Maps_Lab University of Vigo (UVigo) Lewis A Jones, along with four other scientists from University College London and the University of Bristol (UK). The results of this research are published in the journal Nature Communications.

Map Lab is part of the Animal Ecology Group at the UVigo Center for Marine Research and focuses on studying the processes of evolution and extinction over the last 540 million years. In this way, it helps to know where biodiversity appears and disappears over time, generating paleoclimatic maps for that period and programming models that simulate the mechanisms of diversification of life.

The tropical forests of the sea

Currently, coral reefs are concentrated in the tropics and subtropics, where the minimum sea surface temperatures do not fall below 18 °C. All around them live associated organisms, such as corals or reef fish, which make warm-water coral reefs support “the greatest biodiversity of marine organisms on Earth,” says Jones, which is why they are known as tropical marine forests.

A substantial part of this biodiversity It is located in the Indo-Australian archipelago. However, the distribution of reefs was not always the same, in geological past, “Coral reef ecosystems were also located beyond the tropics and, in fact, fossils were found at latitudes >40º”, says the researcher.

The objective of this international team was to determine the causes of such marked differences in the distribution of reefs in the past. “With this study, we provide a interdisciplinary approach and an innovative way to test whether climate has driven the spatial distribution of coral reefs in the geologic past,” says Jones.

paleoclimatic reconstructions

Until now, “climate has been postulated as the main driver of past distributions of coral reefs,” says Jones. For this reason, warmer climate states would lead to greater distributions of coral reefs towards the poles, while a colder weather should lead to distributions restricted to tropical latitudes.

However, no strong relationship was found between global temperature and the latitudinal distribution of coral reefs.

The authors of this study acknowledge that, while this may be surprising, “the fossil record is inherently incomplete and biased, as not all remains of organisms or ecosystems that persisted in the past are in the fossil record,” they conclude.