Cestum jellies are shaped like gliders, with a central cockpit-like mouth flanked by two huge wings. On each wing, countless cell hairs flap back and forth to propel the jelly forward, creating a shimmery prism of rainbow color. When the jellies are feeding, rather than migrating to or from the ocean’s depths, these moving wings create a wake that buffets and frightens would-be prey, such as small shrimp-like copepods
Posts tagged ocean
Hagfish produce slime the way humans produce opinions—readily, swiftly, defensively, and prodigiously. They slime when attacked or simply when stressed. On July 14, 2017, a truck full of hagfish overturned on an Oregon highway. The animals were destined for South Korea, where they are eaten as a delicacy, but instead, they were strewn across a stretch of Highway 101, covering the road (and at least one unfortunate car) in slime. Typically, a hagfish will release less than a teaspoon of gunk from the 100 or so slime glands that line its flanks. And in less than half a second, that little amount will expand by 10,000 times—enough to fill a sizable bucket. Reach in, and every move of your hand will drag the water with it.
“En 1942, l'océanographe et géophysicien Athelstan Frederick Spilhaus d'origine sud-africaine, réalise une carte fascinante. Les régions marines sont représentées au centre du monde. Une immense mer intérieure (un peu plus de 70% de la surface de la Terre) apparait sous nos yeux. Rappelons tout de même que l'Océan mondial génère plus de 60% des services écosystémiques qui nous permettent de vivre, à commencer par la production de la majeure partie de l'oxygène que nous respirons. Cette carte est ainsi toute symbolique de l'importance des mers. Afin de réaliser celle-ci l'auteur utilise les principes des deux projections suivantes. La projection de Ernst Hammer et celle d’August Heinrich Petermann (co-auteur avec Hermann Berghaus et Carl Vogel de l'Atlas Stieler). Le résultat est une projection interrompue dans laquelle les océans forment une unité. C'est à la fois génial et totalement déroutant. La déformation est telle que le continent américain et asiatique sont completement écartelés. L'Europe, l'Afrique et l'Asie du Sud-Est concervent en revanche une forme cohérente.“
Glaciologists usually talk of three distinct regions because they behave slightly differently from each other. In West Antarctica, which is dominated by those marine-terminating glaciers, the assessed losses have climbed from 53 billion to 159 billion tonnes per year over the full period from 1992 to 2017. On the Antarctic Peninsula, the finger of land that points up to South America, the losses have risen from seven billion to 33 billion tonnes annually. This is largely, say scientists, because the floating ice platforms sitting in front of some glaciers have collapsed, allowing the ice behind to flow faster. East Antarctica, the greater part of the continent, is the only region to have shown some growth. Much of this region essentially sits out of the ocean and collects its snows over time and is not subject to the same melting forces seen elsewhere. But the gains are likely quite small, running at about five billion tonnes per year. And the Imbie team stresses that the growth cannot counterbalance what is happening in the West and on the Peninsula. Indeed, it is probable that an unusually big dump of snow in the East just before the last assessment in 2012 made Antarctica as a whole look less negative than the reality. Globally, sea levels are rising by about 3mm a year. This figure is driven by several factors, including the expansion of the oceans as they warm. But what is clear from the latest Imbie assessment is that Antarctica is becoming a significant player. “A three-fold increase now puts Antarctica in the frame as one of the largest contributors to sea-level rise,” said Prof Shepherd, who is affiliated to Leeds University, UK. “The last time we looked at the polar ice sheets, Greenland was the dominant contributor. That’s no longer the case.” In total, Antarctica has shed some 2.7 trillion tonnes of ice since 1992, corresponding to an increase in global sea level of more than 7.5mm.
Trailer for a new documentary entitled, “Sonic Sea,” produced by the National Resources Defense Council (NRDC), and which will premiere on the Discovery Channel on May 19. Description of the documentary from NRDC:
Beneath the surface of our oceans lies a finely balanced, living world of sound, most of which we never hear topside. But to whales, dolphins, and other marine life, sound is survival, the key to how they navigate, find mates, hunt for food, communicate over vast distances, and protect themselves against predators in waters dark and deep.
Our oceans, though, have become vast junkyards of industrial noise — often louder than a rock concert — from commercial shipping, military sonar, and seismic blasts that test for oil and gas. The seas have become so loud, in places, that these great animals are drowning in noise that threatens their health, their future, and their very lives.
On May 19, the Discovery Channel will premiere an important new NRDC film that documents this shattering underwater peril. Sonic Sea calls on us to turn down the volume before it’s too late.
To the future of marine life worldwide, deafening noise is hardly the only threat. It is compounding the stress ocean life faces a growing litany of environmental ills.
Once on the bottom, they waited and watched. And they got some big surprises. “We saw the deepest living fish ever recorded,” says Drazen. “Definitely something new. We took one look at the thing and were amazed — big, wide, winglike fins, this eel-like tail and this scalloped face. It was very unique.” They nicknamed it the “ghost fish” for its almost translucent skin. It appears to be a new species of snailfish — living 5 miles below the surface.
This near-infrared, color view from Cassini shows the sun glinting off of Titan’s north polar seas. (NASA/JPL-Caltech/University of Arizona/University of Idaho)