A study involving researchers from the Interdisciplinary Center for Marine and Environmental Research concluded that, between 2015 and 2019, “mass mortality” events in the Mediterranean Sea were caused by a series of marine heat waves.
In a statement, the Interdisciplinary Center for Marine and Environmental Research (CIIMAR) of the University of Porto said Wednesday that the study, published in the journal Global Change Biology, brought together the efforts of researchers from 11 different countries and addressed, “for the first time”, you effects of mortality on marine biodiversity at a Mediterranean scale.
Led by the Institut de Ciències del Mar (Spain), the research showed that, between 2015 and 2019, the mass mortality events of marine species “affected all Mediterranean regions” due to “marine heat waves that are, each year, more frequent and aggressive”.
The investigation analyzed populations of about 50 species (including corals, sponges and macroalgae) and concluded that they were “affected by these events along thousands of kilometers of the Mediterranean coast, from the Alborão Sea to the eastern coast of the basin”.
In view of the results, the researchers warn that the increase in the intensity and frequency of marine heat waves may be transforming the main coastal ecosystems.
The mortality impacts were observed between the surface and 45 meters deep, where the recorded marine heat waves were exceptional, affecting more than 90% of the Mediterranean basin and reaching temperatures above 26 degrees Celsius in some places”, explains Jean-Baptiste Ledoux. , CIIMAR researcher and one of the authors of the study.
According to research, some of the most affected species are “essential” to maintain operation and the biodiversity of habitats coastal areas such as posidonia oceanica meadows or coral reefs, also known as coral gardens.
In the study, the researchers also found that the incidence and severity of mortality in all corners of the Mediterranean basin is increasing due to marine heat waves.
Unfortunately, the results of the work show that the Mediterranean Sea is experiencing an acceleration of the ecological impacts associated with climate change, which poses an unprecedented threat to the health and functioning of its ecosystems”, observes the researcher from the Porto center.
With the increase in the frequency, intensity and extent of marine heat waves, Jean-Baptiste Ledoux argues that it is essential to “understand the relationship between the different biological responses of marine biodiversity”, but also the different levels of exposure to heat.
The temporal and spatial analysis addressed in the study showed that “there is a significant positive relationship between the duration of hot flashes and the incidence of moral events.”
The mass mortality events in the Mediterranean are equivalent to the bleaching events also consecutively observed in the Great Barrier Reef, suggesting that these episodes are already the norm and not the exception,” says Jean-Baptiste, noting, however , that there is some “variability in the response to heat stress between different individuals of the same species”.
“We are currently trying to understand the factors and processes, genetic or environmental, that underlie resistance to heat stress,” adds the researcher, adding that resistant individuals could be used to restore highly impacted populations.
“However, you need to realize that restoring degraded habitats is logistically very complex and is only realistic at a very local spatial scale,” he adds.
Source: Observadora
