When Academy curators Terry Gosliner and Luiz Rocha traveled to Saudi Arabia this spring to study marine life in the Red Sea and the Gulf of Aden, the contrast awaiting them couldn’t have been starker. Beyond the enclosed campus of King Abdullah University of Science and Technology (KAUST), about an hour north of Jeddah, stretched a parched terrestrial landscape with daytime temperatures hovering near 105 degrees. But once the researchers boarded the 80-foot-long catamaran, they soon ventured into a rich underwater landscape teeming with life.

For the two-part, KAUST-sponsored expedition, Gosliner, Rocha, and a team of 15 international scientists spent two weeks documenting fish diversity in the Red Sea. On the second two-week portion, Rocha and five other researchers continued to explore tropical reefs within the Gulf of Aden, in the territorial waters offshore from Oman. The invitation to collaborate on this general, comprehensive survey arose from Rocha’s participation at a 2012 KAUST conference organized by Michael Berumen that produced a research paper coauthored by Rocha, Berumen,  Brian Bowen, an associate researcher at the University of Hawaii, Joseph DiBattista, a post-doctoral fellow at KAUST, and Michelle Gaither, a post-doctoral fellow at the Academy.

“The sand dunes and rugged mountains along the Saudi coastline reminded me of Baja, California,” says Gosliner. “And the Red Sea’s narrow body of water, caused by tectonic activity and fault lines, is not unlike the Sea of Cortez,” he adds. “That said, the Red Sea has unique features that make it very interesting from a scientific perspective.”

The Arabian Peninsula, wedged between Northeastern Africa and Asia, is bordered by oceans and seas on three sides. The Red Sea, along its western coastline, has a very small, shallow connection with the Indian Ocean. “Because of this geographic separation, it has a lot of unique species,” says Rocha. “There is a lot of endemism in the Red Sea.”

Coastal Oman, at the southeastern end of the peninsula, is open to the Indian Ocean. “It also has many unique species,” says Rocha, “but for a different reason.” The sea is more affected by upwelling that does not impact marine habitats in the rest of the Indian Ocean. Upwelling, caused by wind blowing from coast to ocean, pushes away warm waters on the ocean’s surface. Cold water rises from below to fill the gap.

“You won’t find coral reefs in these conditions—they can’t thrive in cold temperatures,” says Rocha. “Not only is this fauna unique, but the tropical reefs in the Western Indian Ocean are the least known in the world.”

The researchers brought back 350 specimens of nudibranchs and fish for morphological and genetic analysis. The new specimens fill a surprising gap in the Academy’s renowned fish collection.

“We have 250,000 jars of fish at the Academy, about 3 million specimens and 11,000 species,” says Rocha. “Almost everything we brought back is new to the collection. We had very few fish from Oman.”

Another surprise was Gosliner’s assessment of the leading environmental threat to sustaining the region’s biodiversity. “This is an active zone of human activity,” he explains. “To the north, it’s a major shipping corridor through the Suez Canal into the Mediterranean. In the south, you have the Somali pirates.”

And the source of the most severe harm to the ocean biome?

“Overfishing,” says Gosliner. “That has greater impact than all the other activities put together.”

Last but not least: How did the Red Sea get its unusual name? According to Gosliner, a leading theory is that periodic outbreaks of algal blooms caused by dinoflagellates temporarily changed the water’s color.

“When early explorers toured the area,” he says, “they may have seen that phenomenon we now call a ‘red tide.’ But the waters are a sparkling turquoise blue most of the time. So the Red Sea is truly a misnomer.”

Barbara Tannenbaum is a science writer working with the Academy’s Digital Engagement Studio. Her work has appeared in the New York Times, San Francisco Magazine and many other publications.

Image: Terry Gosliner

UC Berkeley’s Roland Burgmann is describing two large earthquakes that occurred in April of this year, in the Indian Ocean, off the coast of Sumatra. While the two ‘quakes caused little damage, the first, measuring magnitude 8.7, was the largest strike-slip temblor ever recorded, and the events seem to be triggering much more than shaking.

Three papers this week in Nature analyze the before, during, and after of the two earthquakes, and all three seem to arrive at the same conclusion: the Indo-Australian tectonic plate is breaking into two separate plates.

If you’ve visited the Academy’s Earthquake exhibit and planetarium show (and you can now do so virtually, through an iTunes course), you know that earthquakes result when continents break apart and plates grind against each other. Scientists say that’s exactly what is happening in this Indo-Australian region right now. Not surprisingly, very slowly.

Thorne Lay, of UC Santa Cruz and co-author on one of the Nature papers, says that the process of forming a new plate boundary will take millions of years and is likely to require hundreds if not thousands of earthquakes like the larger one in April. “This was a huge earthquake, but it’s going to happen again and again to make a through-going fracture that separates the plates.”

Lay and his colleagues’ paper analyzes what happened during the 8.7 quake. It appears that it ruptured over a complex network of at least four faults lying at right angles to one another. According to Lay, the energy released on each fault individually was about magnitude 8, adding up to a total event magnitude of 8.7 (a revised estimate higher than the 8.6 value initially reported). The initial shock was followed two hours later by a magnitude 8.2 aftershock on yet another fault to the south.

The paper by Burgmann and his colleagues from the USGS in Menlo Park, takes it from there. The study shows that these two quakes triggered other, distant earthquakes hours and days later. In fact, the seismologists’ analysis found five times the expected number of quakes during the six days following the April 11 quake and aftershock!

“We found a lot of big events around the world, including a 7.0 quake in Baja California and quakes in Indonesia and Japan, that created significant local shaking,” Burgmann says. “If those quakes had been in an urban area, it could potentially have been disastrous.

“Until now, we seismologists have always said, ‘Don’t worry about distant earthquakes triggering local quakes.’ This study now says that, while it is very rare—it may only happen every few decades—it is a real possibility if the right kind of earthquake happens.”

Image: Thorne Lay/UCSC