“Sharks are remarkably resistant to viruses,” study researcher Michael Zasloff, of the Georgetown University Medical Center, told LiveScience. Zasloff discovered the molecule, squalamine, in 1993 in the dogfish shark, a small- to medium-size shark found in the Atlantic, Pacific, and Indian Oceans.
“It looked like no other compound that had been described in any animal or plant before. It was something completely unique,” Zasloff said. The compound is a potent antibacterial and has shown efficacy in treating human cancers and an eye condition known as macular degeneration, which causes blindness.
By studying the compound’s structure and how it works in the human body, Zasloff thought it might have some antiviral properties. He saw that the molecule works by sticking to the cell membranes of the liver and blood vessels. While there, it kicks off other proteins, some of which are essential for viruses to enter and survive in the cell.
The researchers decided to test the compound on several different live viruses that infect liver cells, including hepatitis B, dengue virus and yellow fever. They saw high efficacy across the board.
Zasloff hopes to start human trials in the next few years.
Marc Maresca, a researcher at Paul Cézanne University in Aix-en-Provence, France, who wasn’t involved in the study, agreed that the concentrations used were quite high, possibly in toxic ranges for some cells, but in an email to LiveScience Meresca also called the study “very exciting.”
Lithodid crabs (and other skeleton-crushing predators) may have been excluded from cold Antarctic continental shelf waters for more than 14 Myr [million years]. The west Antarctic Peninsula shelf is warming rapidly and has been hypothesized to be soon invaded by lithodids. A remotely operated vehicle survey in Palmer Deep, a basin 120 km onto the Antarctic shelf, revealed a large, reproductive population of lithodids, providing the first evidence that king crabs have crossed the Antarctic shelf. DNA sequencing and morphology indicate the lithodid is Neolithodes yaldwyni Ahyong & Dawson, previously reported only from Ross Sea waters. We estimate a N. yaldwyni population density of 10 600 km−2 and a population size of 1.55 × 106 in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia. The lithodid occurred at depths of more than 850 m and temperatures of more than 1.4°C in Palmer Deep, and was not found in extensive surveys of the colder shelf at depths of 430–725 m. Where N. yaldwyni occurred, crab traces were abundant, megafaunal diversity reduced and echinoderms absent, suggesting that the crabs have major ecological impacts. Antarctic Peninsula shelf waters are warming at approximately 0.01°C yr−1; if N. yaldwyni is currently limited by cold temperatures, it could spread up onto the shelf (400–600 m depths) within 1–2 decades. The Palmer Deep N. yaldwyni population provides an important model for the potential invasive impacts of crushing predators on vulnerable Antarctic shelf ecosystems.
In a new report, [an expert panel of scientists] warn that ocean life is “at high risk of entering a phase of extinction of marine species unprecedented in human history”. They conclude that issues such as over-fishing, pollution and climate change are acting together in ways that have not previously been recognised.
ocean acidification, warming, local pollution and overfishing are acting together to increase the threat to coral reefs – so much so that three-quarters of the world’s reefs are at risk of severe decline.
The report also notes that previous mass extinction events have been associated with trends being observed now – disturbances of the carbon cycle, and acidification and hypoxia (depletion of oxygen) of seawater.
Levels of CO2 being absorbed by the oceans are already far greater than during the great extinction of marine species 55 million years ago (during the Paleocene-Eocene Thermal Maximum), it concludes.
The overfishing of our oceans has been a problem for over 100 years and a known problem, that we continue to give too little attention to. Adding to that impacts of climate change and the state of ocean life is in trouble. The decision of our population to not deal with the causes of climate change will have very bad consequences. It is a shame we have so little caring about the consequences of our decisions. And even sadder that our “leaders” do such an appalling job of leading – instead they pander to selfish immediate gratification.
Jellyfish is a common name for gelatinous water dwelling animals. The diversity of these invertebrates is amazing. And what actually counts as a jellyfish is not easy to determine. Watch this great video to learn about Cnidarians, Urochordata, Polychaetes and Ctenophores.
This image shows the abundance of life in the sea, measured by the SeaWiFS instrument aboard the Seastar satellite. Dark blue represents warmer areas where there is little life due to lack of nutrients, and greens and reds represent cooler nutrient-rich areas.
The nutrient-rich areas include coastal regions where cold water rises from the sea floor bringing nutrients along and areas at the mouths of rivers where the rivers have brought nutrients into the ocean from the land. NASA has posted a large gallery of great images for Earth Day.
Whales’ sizes stretch the imagination from the 100-foot (30-meter) long blue whale – the largest animal to have ever existed – to a small species about the size of a dog.
Around 35 million years ago, when modern whales began to appear in the ocean, whale evolution ignited. Whales began as basically similar body types and evolved into everything from porpoises to blue whales over the next 5 million years, said study lead author Graham Slater of UCLA. “Five million years is like the blink of an eye,” Slater told LiveScience.
The finding supports what’s known as the explosive radiation hypothesis. The idea is that a few key traits allowed the earliest ancestors of modern cetaceans – marine mammals, including whales, dolphins and porpoises – to explore new ways of living. Once these ancestors branched out into a new body form, they stayed the course.
The key traits credited with the explosive evolution include sonar, large brains, baleen (the stringy looking stuff across some whales’ mouths that filters small animals from sea water), and complex sociality.
mighty microbes, which constitute 50 to 90 percent of the oceans’ total biomass, according to newly released data.
These tiny creatures can join together to create some of the largest masses of life on the planet, and researchers working on the decade-long Census of Marine Life project found one such seafloor mat off the Pacific coast of South America that is roughly the size of Greece.
A single liter of seawater, once thought to contain about 100,000 microbes, can actually hold more than one billion microorganisms, the census scientists reported. But these small creatures don’t just live in the water column or on the seafloor. Large communities of microscopic animals have even been discovered more than one thousand meters beneath the seafloor. Some of these deep burrowers, such as loriciferans, are only a quarter of a millimeter long.
“Far from being a lifeless desert, the deep sea rivals such highly diverse ecosystems as tropical rainforests and coral reefs,”
Microbes help to turn atmospheric carbon dioxide into usable carbon, completing about 95 percent of all respiration in the Earth’s oceans…
Sea lions fitted with GPS trackers and a National Geographic Crittercam are taking scientists on amazing journeys to previously unknown marine ‘hot spots.’ These areas are important not only for providing the sea lions’ food, but also for maintaining fish populations.
The Crittercams were deployed at Dangerous Reef in Spencer Gulf, a rocky island the size of a football field, and home to the biggest Australian sea lion colony.
Dr. Page says, “One important discovery is that the sea lions always feed on the sea floor” and they don’t eat open ocean fish, known as pelagic. “This is critical information because the marine parks are being set up to protect sea floor habitats,” a move that the scientists can now confirm will protect critical sea lion resources.
In one of the more spectacular pieces of Crittercam video so far, we can see this female working hard to handle a challenging prey item – a large octopus. Too big to swallow in one gulp, she drags it to the surface where she can breathe while she works at breaking it down into bite-size pieces.
A three-inch long Lyssianasid amphipod found 600 feet beneath the Ross Ice Shelf stars in a recent popular webcast (see below). NASA scientists were using a borehole camera to look back up towards the ice surface when they spotted this pinkish-orange creature swimming beneath the ice.
Stacy Kim of Moss Landing Marine Laboratory was the first biologist to see the video and immediately recognized it as a Lyssianasid amphipod. It was about 3 inches long and Stacy concluded that this meant there was quite an extensive biological community under the ice here – even 20 miles from open water.
the autonomous underwater vehicle (AUV) used a piece of software called “T rex”, which operates in a similar way to the software used to control Nasa’s Mars Exploration Rovers – helping them to avoid obstacles on the surface of the Red Planet.
One main difference between the two pieces of software is that for the Mars rovers, the software ran in the control centre on Earth. With this marine vehicle, it runs onboard the robotic vehicle.
“We tell it, ‘here’s the range of tasks that we want you to perform’, and it goes off and assesses what is happening in the ocean, making decisions about how much of the range it will cover to get back the data we want.”
Researchers at MBARI used the Gulper AUV to monitor potentially harmful algal blooms.
Kim Fulton-Bennett from MBARI explained: “We used to send out a ship for a full day every few weeks to manually take these measurements. Now we just take the AUV outside the harbour and send it on its way.
“About 24 hours later, it comes back, we hoist it on board, and download the data.”