Mediterranean analysis indicates that 90% of the subtidal populations of cockles, whelks and other animals have collapsed.
In the eastern Mediterranean, one of the fastest-warming areas on Earth, the world’s most catastrophic climate-related loss of marine life has been found. According to a new study that raises questions about the broader environment and neighboring areas, 90 percent of native mollusk populations along the coast of Israel have declined in recent decades because they can not withstand the increasingly hot waters. The researchers said that sharp decreases in indigenous cockles, whelks, and other shallow subtidal invertebrates are likely to have spread to waters off other lands in the area and will continue as global temperatures rise westward to Greece and beyond. Revisited: As the oceans warm, what happens? The paper – published in the journal Proceedings of the Royal Society B – reports that indigenous mollusc populations have decreased in shallow subtidal sediment substrates to 12 percent of their historical species richness and to 5 percent on rocky substrates. The authors of the paper expressed surprise at their results. Paolo Albano, a marine biologist at the University of Vienna, said, “The extent was totally unexpected,” I wanted a seascape that, as a Mediterranean expert, I was used to, but enriched by some interesting exotic species that had invaded the Suez Canal.
But what I found was a desert, completely empty of even common Mediterranean species. “For example, the murex is a snail used since Roman times for the Tyrian purple dye used in clothing throughout the Mediterranean region.”
Several sites were collected by the research team and then the number of living mollusks was compared with previous population sizes calculated from empty shells contained in the sediment. The deficit surpassed anything previously seen. This is the largest to date recorded climate-driven, regional-scale loss of diversity in the oceans,”This is the largest climate-driven, regional-scale loss of diversity in the oceans documented to date,”
Temperatures are lower in deeper waters.
Species have developed in intertidal zones to adapt to broader ranges of temperatures.
Native mollusks are declining in between, with far-reaching effects, such as reductions in pollinators and the consistency of the soil on land.
The largest marine phylum is made up of mollusks, accounting for 23 percent of all marine species.
They play an important role in controlling ocean chemistry by recycling nutrients and extracting nitrogen and phosphorus, in addition to providing meat for the fishing industry.
New invasive tropical species from the Red Sea might take over some of this role, but preliminary results indicate that they will not play the same role in the ecosystem as the native species that have disappeared. “The environment is going to be distinct and operate differently. That’s really simple.
But the situation is so complex that the effects are difficult to foresee,’ said Albano. Scientists say the cause of the catastrophe is climate change caused by humans. Between 1980 and 2013, the Israeli coast – which is one of the hottest areas of the Mediterranean – witnessed a 3C temperature rise. The summer surface temperature average is 32C. This is thought to have caused the disappearance of native mollusk populations – a phenomenon reported elsewhere in previous studies. Less important causes were considered to be pollution and the arrival of tropical species into the Suez Canal. Pollution was more likely to be discovered near ports such as Haifa, and for over 150 years the canal has existed.
Coastline surveys showed safe waters in the 1970s and ’80s. Albano said the decline possibly took place in the last 20 years and impacted the entire ecosystem. “The sea is transforming fully from temperate Mediterranean to impoverished tropical. This transition is rapid and continuing.
Albano claims that this is part of an irreversible pattern as global warming makes the relatively cool Mediterranean more like the tropical Red Sea. Albano believes that global warming makes the relatively cool Mediterranean Sea more like the tropical Red Sea, a trend that is often seen in the far north, where the cold Arctic Ocean resees