Tag Archives: marine biology

Credit: Giphy/YouTube.

Adorable Dumbo octopus makes surprise appearance on camera

Credit: Giphy/YouTube.

Credit: Giphy/YouTube.

Thousands of feet below the ocean’s surface, scientists came across a dazzling sight with the help of the prying eye of an unmanned robotic submersible. Under a background of giggles and ovations, the video that the researchers recorded features an adorable-looking dumbo octopus, named so because its flapping fins on the side of its head resemble the famous Disney character.

There are 13 known species of dumbo octopuses (Grimpoteuthis), all of whom live close to the ocean floor at depths of 3,000 to 4,000 meters (9,800 to 13,000 feet). These small animals are easily recognizable by a pair of fins located on their mantle and webbing between their eight arms. Their favorite food is comprised of snails, worms, and other creatures that live on the ocean floor.

At such depths, catching a glimpse of a dumbo octopus is very rare, which explains all the “all my gosh!” reactions of the crew from the E/V Nautilus research vessel. The actual footage was shot by a remotely-operated vehicle (ROV) named Hercules.

“Oh, and the world loves a dumbo,” one of the crew marveled. And I’m sure we all can agree.

While the researchers were enraptured by the eerie sight, they still made sure to study the animal. Lasers mounted on the ROV measured the deep-sea ghost at 60 cm (2 feet) long, which is on the hefty side as far as these species are concerned.

Although they were grateful for Dumbo’s visit, the researchers weren’t actually searching for it. Instead, they were tasked with surveying the Davidson Seamount, an extinct volcano in Monterey Bay National Marine Sanctuary.

The Monterey Bay region where the Dumbo octopus was sighted is packed with corals, sponges, and numerous other invertebrates — a sort of ‘oasis of the deep’ that attracts all sorts of animals. Indeed such hotspots are teeming with life as the researchers would come to know. Only a few days after the Dumbo sighting, the Nautilus crew stumbled across an immense octopus nesting site where more than 1,000 mothers were nursing their young.

 

New Hebrides trench: First pictures of unexplored deep sea

For the first time, researchers have taken a look at the life that thrives in one of the deepest spots in the ocean. They investigated the New Hebrides trench, located just West of Vanuatu, and revealed that cusk eels and crustaceans teem more than 7,000m (23,000ft) down. They used cameras fitted on an unmanned lander to film the deep-sea creatures.

The fact that this is happening at a depth of 7 kilometers simply blows my mind.

Marine biologists were surprised to see that life in this trench significantly differed from other regions of the deep that had been studied – painting a good picture of just how spectacular and interesting this extreme biodiversity really is.

“We’re starting to find out that what happens at one trench doesn’t necessarily represent what happens in all the trenches,” said Dr Alan Jamieson, from Oceanlab at the University of Aberdeen, UK, who carried out the expedition with the National Institute of Water and Atmospheric Research in New Zealand.

The 30 day expedition was largely successful showing large, grey cusk eels up to 1 meter long, chopping on the bait, as well as large, bright red prawns scrabbling around on the sandy seabed which reaches 7.200 meters in its deepest point. They also spotted eel pouts, arrow-tooth eels and thousands of smaller crustaceans – some of which were unfortunate enough to be captured and taken back to the surface.

There are over 30 deep trenches across the world, most of them in the Pacific Ocean, due to its very intense tectonics. Until this expedition, the New Hebrides Trench (which is also some 1.500 km away from New Zealand) has been relatively unstudied – from a biological point of view. When compared to other, apparently similar areas, the differences are major.

Dr Jamieson said:

“The surprising thing was that there was a complete and utter lack of one of the most common deep sea fish we would expect to see. Anywhere else around the Pacific Rim, around the trenches we’ve looked at, you see a lot of grenadiers – they are quite a conspicuous part of the deep-sea community. But when we went to the New Hebrides trench, we didn’t see a single one.

“But what we did see was a fish called the cusk eel. These turn up elsewhere but in very, very low numbers. But around the New Hebrides trench, these – and the prawns – were all that we saw.”

They also reported a rather surprising absence of a certain snailfish, a small pink fish commonly found throughout the world’s trenches. They believe the differences lie in the absence of a major nutrient source in the New Hebrides Trench.

“If you look at the New Hebrides trench, and where it is geographically, it lies under very unproductive waters – there is not a lot happening at the surface of the tropical waters,” said Dr Jamieson. It seems the cusk eels are specialists in very low food environments, whereas the grenadiers require a greater source of food.”

This expedition is part of a larger wave to explore the very depths of the planetary ocean, which can go even 11 km deep, in the Mariana Trench. Almost all of this has been carried out using landers or other unmanned vehicles, but in 2012 Hollywood movie director James Cameron made a record-breaking dive to the deepest place in the ocean – the Mariana trench. He described it as an alien place, devoid of life. This is the situation not so much because of the depth, but rather because it is so far from the continental shelf, which means that very few nutrients drift into it. However, researchers have shown that while it may be devoid of macroscopic life, microscopic life still thrives – even in this fantastically extreme environment.

Humpback Whale

Humpack whales flawless natural navigation studied

Humpback Whale

A recently published study 8 years in the making reveals the uncanny ability humpback whales have of following seemingly perfect straight paths for weeks at a time. The navigational precision of humpback whales cannot be explained by known theories.

Humpback whales feed during the summer near polar oceans and migrate to warm tropical oceans for the winter, where they mate and calves are born. This means that during a year a single humpback whale can easily amass 10,000 miles worth of return journeys, making them one of the most farthest migrating animals on Earth. Their migrating paths are perfectly straight, sometimes deviated only by a few degrees, fact that poised researchers to study them and see exactly what mechanism compels the huge watery mammals to become such precise navigators.

Researchers from the University of Canterbury, in Christchurch, tracked 16 radio-tagged whales as they migrated thousands of miles north from the South Atlantic and South Pacific with unswerving accuracy, often covering more than 600 miles but deviating off course by less than one degree.

“Such remarkable directional precision is difficult to explain by established models of directional orientation,” the researchers, led by Travis Horton from the University of Canterbury, wrote in the Royal Society journal Biology Letters.

Each animal was tagged with a special positioning device which attached to the whale from four weeks to seven months before falling out, transmitting precise position data and provided one of the most detailed sets of long-term migratory data for humpbacks ever collected.

Most long-distance traveling animals are believed to navigate using an internal compass that relies either on the earth’s magnetic field or the position of the sun. However, the scientists wrote, “it seems unlikely that individual magnetic and solar orientation cues can, in isolation, explain the extreme navigational precision achieved by humpback whales.”

They instead added, “The relatively slow movements of humpback whales, combined with their clear ability to navigate with extreme precision over long distances, present outstanding opportunities to explore alternative mechanisms of migratory orientation.”

Earth’s magnetism varies too much to explain the whales’ arrow-straight patterns, and you can’t really rely on solar navigation when navigating through water.

“Humpback whales are going across some of most turbulent waters in the world, yet they keep going straight,” said environmental scientist Travis Horton of the University of Canterbury, whose team will publish their findings April 20 in Biology Letters. “They’re orienting with something outside of themselves, not something internal.”

Horton suspects humpbacks rely on both mechanisms, and perhaps the position of the moon or stars. John Calambokidis of the Cascadia Research Collective, suggested a fourth mechanism for steering: long-distance songs that can carry for hundreds or thousands of miles underwater, and may provide navigational cues or help migrating whales coordinate their movements.

“These whales are clearly using something more sophisticated to migrate than anything we’ve surmised,” said Calambokidis. “I’m really looking forward to seeing what this team does next.”

Prepared to see, correction, hear something really amazing? Check out the video below.

UPDATE: a recent study has finally proven that sockeye salmon indeed rely on magnetic field to guide itself back to the freshwater stream of their birth – a trait that’s believed to be also used by the humpbacked whale.

Whales suffer from sun burns too

You know those days when you go to the beach, and it’s just too hot outside, so you have to use some cream and all ? Well, it’s a little harder if you’re a whale. A recent study conducted that a whole lot of whales displayed blisters caused by sun damage.

Laura Martinez-Levasseur, from the Zoological Society of London (ZSL) and Queen Mary, University of London studied more than 150 whales from the Gulf of California, by taking pictures as well as skin samples; she explained that whales are a good model for studying marine animals, because “they need to come to the surface to breathe air, to socialise and to feed their young, meaning that they are frequently exposed to the full force of the sun”.

Examining the high res pictures they located the blisters and then put the skin samples under the microscope. The results were conclusive: the blisters were caused by sun burns. They also found something else, that paler coloured whales are more exposed to this kind of damage. Darker whales have more cells that produce a dark pigment called melanin. In humans, this is the result of a slight DNA altering caused by sun burn, and all signs seem to indicate the same thing in other mammals.

“This is the first evidence that the Sun’s rays can cause skin lesions in whales,” said Ms Martinez-Levasseur.
“The increase in skin damage seen in blue whales is a matter of concern, but at this stage it is not clear what is causing this increase. A likely candidate is rising ultraviolet radiation as a result of either ozone depletion, or a change in the level of cloud cover.”

The similarities to humans don’t stop here though. Professor Edel O’Toole, a skin specialist also involved in the study said:

“As we expect to see in humans, the whale species that spent more time in the sun suffered greater sun damage. We predict that whales will experience more severe sun damage if ultraviolet radiation continues to increase.”

The study showed no signs of skin cancer, but research is still going on. Other marine animals are also exposed to this kind of burns, especially hairless animals, like dolphins for example. The damage is also more serious in the areas with more ozone depletion, especially in the poles.