The Mediterranean experienced its highest temperature in four decades on 26 July, according to the Institute of Marine Sciences in Spain.
The data, gathered from satellites belonging to the European Earth observation program Copernicus, indicated an increase in water surface temperature, which reached 28.71°C. This temperature surpassed the previous record set in 2003, which stood at 28.25°C.
Oceans worldwide have been experiencing higher temperatures, with the average global sea surface temperature reaching a devastating 20.96°C in August, breaking the 2016 record of 20.95°C. Between 2015 and 2019, marine heatwaves on such levels led to the extinction of about 50 species, including corals and molluscs.
Rising temperatures could have an irreversible impact on marine wildlife as mobile species migrate to colder waters, throwing entire ecosystems into disarray. Sedentary species, on the other hand, are more vulnerable to heat stress because of their inability to migrate.
In light of these alarming developments, here are seven Mediterranean species currently facing increasing threats to their survival and well-being.
Because they live in shallow waters, corals are more vulnerable to marine heatwaves. One of the most important bioengineering organisms in the Mediterranean, Gorgonians, are susceptible to rising temperatures above their normal thermal range.
A decrease in gorgonian numbers could cause an imbalance in the Mediterranean’s ecosystem, as a myriad of species benefit from breeding, feeding, and living within the countless interlacing branches of corals in this submerged stone forest.
Holding the record for the second largest animal on earth after blue whales, fin whales are one of the most majestic species traversing the Mediterranean waters. It is the only species of baleen whale that regularly lives in Mediterranean waters; it can grow up to 25 meters long. It has an average adult length of 18 to 22 meters, and a weight of 90 tons.
Fin whales are one of the few species of whales that are known to reside in Egyptian waters.
Variations in water temperature and currents could influence the timing of vital environmental cues necessary for fin whales’ navigation and feeding behaviors. This disturbance puts the local fin whale population, which is already vulnerable, at grave risk.
Another vulnerable Mediterranean species is the sperm whale. Weighing 35 to 45 tons, these animals have the largest brain of any organism that has lived on the planet. The Red List of Threatened Species of the International Union for Conservation of Nature (IUCN) considers the Mediterranean population to have less than 2500 mature individuals and lists it as endangered.
Due to rising temperatures, sperm whales are altering their migration routes in response to changes in water temperatures. They extend their stays in certain habitats and avoid reaching other locations altogether, affecting their food distribution, sexual health, and survival, which could have alarming consequences.
This shift raises concerns not only for the ecosystems dependent on traditional whale migration patterns, but also because new regions may lack the necessary resources to sustain the feeding requirements of these whales.
The Loggerhead Turtle
The IUCN lists the loggerhead turtle as vulnerable. Its name was derived from its prominent head, housing robust jaw muscles that enable it to consume prey, particularly those encased in a tough shell like snails and oysters.
Loggerhead turtles are one of the most common turtle species that can be found in Egypt. Elevated temperatures on nesting beaches will also affect sea turtles. As reptiles, sea turtles depend on the temperature of the sand where their eggs are incubated to determine the gender of the hatchlings within a nest. An imbalance of male and female hatchlings as a result of high temperatures puts the entire species at risk.
The Mediterranean monk seal, the only member of the Monachus genus, is one of the world’s two remaining monk seal species. Like the Hawaiian monk seal, the Mediterranean variant is at risk of extinction, with a population of less than 700 individuals.
Climate change has contributed to the breakdown of multiple food chains. Thermal stratifications – a process in which melting ice caused by climate change expands the volume of water, providing freshwater to the ocean and decreasing salinity – have reduced nutrient transfer to the water’s surface, impeding the development of immediate energy producers like phytoplankton.
This sequence of events has had a cascading impact, adversely affecting apex predators such as the Mediterranean monk seal.
The bluefin tuna, a top predator in marine ecosystems, is among the biggest, fastest, and most gorgeously colored fish species on the earth. Their torpedo-like, streamlined bodies are built for both speed and endurance.
Both larval and adult survival rates of bluefin tuna decreased when surface temperatures rose, especially in the warmest sections of the water column. On the other hand, survival rates increased at greater depths in areas with cooler water. According to this, cooler waters are preferred by temperate bluefin tuna, which also appear to be negatively impacted by rising temperatures.
The common goby is a small fish in the Mediterranean Sea and nearby waters. It adapts to its surroundings with various colors and patterns, favoring habitats like muddy or sandy coastal areas, seagrass patches, and tide pools. Gobies are essential to the region because they serve as markers of the health of the aquatic ecology. A 2018 study revealed that a rise of 3°C in temperature could cause a population decline of the common goby.
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