Tag: Mediterranean Sea

Can climate change affect volcanic activity?

Vesuvius is part of a volcanic region that became more active when the Mediterranean Sea dried up about 5 million years ago. A study of the era suggests climate change can influence volcanic activity. @bberwyn photo.

Study suggests link between sea level and eruptions

Staff Report

European researchers say they’ve found more evidence supporting links between climate change and volcanic activity.

Geologists from Switzerland, France and Spain studied compared data on eruptions and climate from about 5 million years ago, finding that volcanic activity in southern Europe doubled during a time when the Mediterranean Sea dried up. They suspect that the changes on the surface contributed to the way magma behaves deep in the Earth.

The era they studied is known as the Messinian salinity crisis, when the Strait of Gibraltar was blocked and the Mediterranean temporarily isolated from the Atlantic, according to the study published in Nature Geoscience.

The geological record shows a sharp increase in volcanic activity, and the scientists concluded the spike can best be explained by the almost total drying out of the Mediterranean.

The trait of Gibraltar was shut on a temporary basis during the Messinian Era (from 5.96 to 5.33 million years ago) and that the Mediterranean Sea was isolated from the Atlantic. Thick layers of salt on the seabed, as well as river canyons carved through land that is now submerged, suggest the Mediterranean Sea’s level was much lower.

The study acknowledges that this hypothesis continues to be a source of debate, while exploring the potential links.

In a statement, University of Geneva geologist Pietro Sternai said it’s clear that changes at the surface of the Earth, like a sudden lowering of sea level, can change the pressure deep down around pockets of molten magma. Based on that, the researchers studied the changes in volcanic activity during the period. Tracing the age of crystals in volcanic deposits, they counted 13 eruptions around the Mediterranean between 5.9 and 5.3 million years ago — more than double the average over comparable time periods.

Why is the figure so high?

“The single logical explanation is the hypothesis that the sea dried out, since this is the only event powerful enough to alter the Earth’s pressure and magmatic production over the entire Mediterranean,” Sternai said.

The team used computer models to simulate the effect of the Mediterranean’s desiccation on pressure at depth and the impact on magma production. According to Sternai, the models show the only way to account for the increased vulcanism was that the level of the Mediterranean Sea dropped by about two kilometres.

Related research has suggested that melting ice sheets in the polar regions, as well as melting glaciers, could also contribute in various ways to increased volcanic activity.

 

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Fishing still a big threat to loggerhead turtles in Mediterranean

More protection needed in feeding areas

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Thousands of loggerhead sea turtles are dying in fishing nets in the southern and eastern Mediterranean. Photo via the Creative Common and Wikipedia.

Staff Report

Although key loggerhead sea turtle nesting areas around Cyprus, Greece and Turkey are relatively well-protected, the species is still vulnerable to small-scale fishing operations around Syria, Libya and Egypt and Tunisia. Thousand of the sea turtles, on the IUCN Red List, are killed each year when they travel to to those regions in search of food, according to a new study led by researchers at the University of Exeter. Continue reading “Fishing still a big threat to loggerhead turtles in Mediterranean”

Biologists map key habitat for Mediterranean sea turtles

Green sea turtle conservation
Green sea turtle. Photo courtesy Andy Bruckner/NOAA.

New marine protected area needed to protect the threatened species

Staff Report

FRISCO — UK scientists say that, based on mapping of critical foraging grounds for green sea turtles in the Mediterranean they recommend creation of a new marine protected areas to help protect the species, identified as “endangered” on the IUCN Red List.

The study involved tracking turtles from breeding grounds in Cyprus, Turkey, Israel and Syria and pinpointing ten foraging grounds. Two major hotspots in Libya account for more than half of the turtles which were tracked to conclusive endpoints.

Recent green sea turtle studies by U.S. scientists show how protected areas can help protect the species. The U.S. Geological Survey researchers confirmed the turtles’ use of the protected areas by tracking nesting turtles with satellite tags and analyzing their movement patterns after they left beaches in the Florida Keys. Continue reading “Biologists map key habitat for Mediterranean sea turtles”

Recreational anglers impacting Mediterranean fish stocks

A couple of young Slovenians wet a line in the Adriatic. PHOTO BY LEIGH WADDEN.
A couple of young Slovenians wet a line in the Adriatic.

Some protected species ‘caught for fun’

Staff Report

FRISCO — Scientists taking a close look at fishing in the Mediterranean Sea say recreational anglers may, in some cases, have just as much of an impact on resources as commercial fisheries.

More regulation is needed to ensure the sustainability of some species, the researchers concluded in their study published in Reviews in Fisheries Science & Aquaculture.

“Both types of fishing can have similar biological and ecological effects on fish populations and on marine ecosystems,” said Toni Font, a researcher with the department of Environmental Sciences at Girona University (Spain). Continue reading “Recreational anglers impacting Mediterranean fish stocks”

Climate: Invasive tropical fish already changing ocean ecosystems in eastern Mediterranean Sea

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Rabbitfish are changing ecosystems in the Mediterranean Sea.

Studies document loss of kelp forests and overall biodiversity

Staff Report

FRISCO — Tropical fish are moving north as the global climate warms, in some cases with devastating impacts to ocean ecosystems. In parts of the eastern Mediterranean Sea, rabbitfish have reduced the algae canopy by 65 percent with a cascading effect on ecosystems, including a 40 percent decrease in the total number of plant and animal species.

“The introduction of tropical fish into more temperate regions is troubling and this new study gives a vivid example of what can happen when non-native species occupy a new ecosystem,” said Fiona Tomas Nash, a courtesy professor of fisheries and wildlife at Oregon State University and a co-author on both studies. Continue reading “Climate: Invasive tropical fish already changing ocean ecosystems in eastern Mediterranean Sea”

Global warming aids spread of invasive fish in Mediterranean Sea

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A juvenile rabbitfish, an invasive species blamed for wiping out huge areas of ocean habitat. Photo courtesy Zafer Kizilkaya.

Ocean ecosystems at risk from fish that kills algal forests

Staff Report

FRISCO — The spread of invasive tropical fish into previously temperate waters is also affecting the Mediterranean Sea, according to Australian scientist monitoring the spread of rabbitfish which have already devastated algal forests in the eastern Mediterranean Sea.

Global warming may help the fish spread into the entire Mediterranean Basin, researcher warned in a new paper published in the Journal of Ecology (Authors: Dr. Adriana Vergés, of the University of New South Wales, Australia, and Dr. Fiona Tomas of the Mediterranean Institute for Advanced Studies in Spain). Continue reading “Global warming aids spread of invasive fish in Mediterranean Sea”

Oceans: Mediterranean fish in steady decline

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Albanian fishermen tend nets in Saranda. bberwyn photo.

Unregulated coastal fisheries, juvenile catch threaten sustainability

Staff Report

FRISCO — Stocks of commercially valuable fish in the Mediterranean Sea are disappearing steadily because of a lack of good planning and management, as well as inadequate enforcement of existing regulations. Without action, some species are likely to disappear, scientists warned last week in a report showing that fisheries resources in the Mediterranean have deteriorated in the past 20 years.

The report evaluated nine fish species and called for stringent monitoring of Mediterranean fishing activities, better enforcement of fisheries regulations, and advanced management plans in Mediterranean waters. The findings were published July 10 in the Cell Press journal Current Biology.
Continue reading “Oceans: Mediterranean fish in steady decline”