Past events of mass mortality in Mediterranean sponge communities have been linked to extended periods of high-temperature anomalies, yet it is unknown how a gradual change, such as the constant rise in global seawater temperatures, will affect biodiversity.
This study presents a case study of Agelas oroides, a common Mediterranean sponge that was thought to be lost from the Israeli coastal fauna but has been recently rediscovered in mesophotic depths. The authors examined whether it can survive the present conditions in the shallow Israeli coast, where temperatures increased by 3º C during the past 60 years. This was done by transplanting mesophotic sponges to a shallow rocky habitat.
The results showed that the transplanted sponges survival decreased only when the ambient temperature exceeded 28º C.
The authors conclude that a prolonged period of high temperatures may constitute a major factor in A. oroides survival and disappearance from the Israeli shallow habitats.
Idan et al. (2020) Sponges in a changing climate: survival of Agelas oroides in a warming Mediterranean Sea. Frontiers in Marine Science doi:10.3389/fmars.2020.603593