marine organisms

Jade and striped icebergs. “When seawater at depths of more than 1,200 feet freezes to the underside of massive ice shelves like East Antarctica’s Amery Ice Shelf, it forms ‘marine ice.’ Enormous hunks of ice calve—or break off—from the ice shelf, creating icebergs. When one of these icebergs overturns, its jade underside is revealed. The wondrous color of this ‘marine ice’ results from organic matter dissolved in the seawater at those great depths,” explained Audubon Magazine. “Green icebergs are infrequently seen because their verdant bellies are underwater; it’s only when they flip over, a rare event, that their richly colored regions can be seen before they melt. Striped icebergs, perhaps even more scarce than jade bergs, are thought to form in one of two ways: either meltwater refreezes in crevasses formed atop glaciers before they calve icebergs (creating blue stripes), or seawater freezes inside cracks beneath ice shelves (creating green stripes).”

Photo #14 by Steve Nicol via Australian Antarctic Division

Typically measuring ~88 centimeters (but with recordings found up to 104 centimeters), the venomous golden cow-nose rays migrate in groups of up to 10,000 as they make their way towards their summer feeding grounds in the Gulf of Mexico. 

Plankton in the news!

Studying microscopic organisms teaches us critical lessons about our world. The research schooner Tara, which has been traveling the oceans since 2009, is greatly increasing our knowledge of tiny marine organisms, including plankton. This week’s issue of Science magazine features the Tara’s research on plankton and other marine organisms, with lots of beautiful photos! Read more about the Tara here and here. The Exploratorium’s biology lab is also collecting plankton data and photographs from our home at Pier 15, and contributing a piece to the global plankton puzzle.


Deep sea ‘mushroom’ may be new branch of life

A mushroom-shaped sea animal discovered off the Australian coast has defied classification in the tree of life.

A team of scientists at the University of Copenhagen says the tiny organism does not fit into any of the known subdivisions of the animal kingdom.

Such a situation has occurred only a handful of times in the last 100 years.

The organisms, which were originally collected in 1986, are described in the academic journal Plos One.

“Finding something like this is extremely rare, it’s maybe only happened about four times in the last 100 years,” said co-author Jorgen Olesen from the University of Copenhagen.

He told BBC News: “We think it belongs in the animal kingdom somewhere; the question is where.”

The new organisms are multicellular but mostly non-symmetrical, with a dense layer of gelatinous material between the outer skin cell and inner stomach cell layers. (more)

  • Phylum: Arthropoda
  • Subphylum: Chelicerata 
  • Class: Arachnida 

This is the Diving Bell spider and is the only spider known to live its entire life under water. It breathes air but it does so by trapping air in a bubble and holding onto it with hairs on its abdomen and legs while underwater. This bubble (bell) permits gas exchange with the surrounding water; taking in oxygen and releasing carbon dioxide. The spider will spend most of its time in this bubble and very rarely needs to replenish the air thanks to the gas exchange. 

Fairburn fortifications

The state gemstone of South Dakota is one of the most beautiful agates on Earth, with lovely banding patterns and (in the best specimens) bright red, orange and brown colours due to iron oxides. Named after the town nearest to where it occurs, it is a target for rockhounds across the country (see They were first discovered in the late 19th century, though native peoples had known of them since time immemorial.

Keep reading
Oceans may become too acidic for animals to smell their way around
'Smell-free seas' would be a disaster for marine life.
By Mark Lorch

The oceans are becoming ever more acidic as humans pump increasing amounts of carbon dioxide into the atmosphere. These acidic oceans will change smell molecules and render them unrecognisable for animals in the sea.

Chemical communication using smell is essential for marine organisms. Its importance is comparable to the combined status of vision and hearing in humans. My latest research reveals that smell molecules in the ocean are significantly affected by ongoing ocean acidification.

Smell molecules are chemicals that are produced by organisms either on purpose – by females to attract males, for instance – or by chance during natural processes such as protein degradation. In both cases, they can be used by animals to smell their way around.

Imagine you are a little crab living on a shore covered with large rocks and deep pools, and battered by tides and waves. The only way to find your lunchtime snack would be to smell it from a distance. But the same also applies to the octopus hunting you. So you, the crab, also rely on smelling the octopus first to avoid being eaten. What if all this were no longer possible?

Man-made, increasing carbon dioxide emissions have caused the pH in our world’s oceans to decrease, an effect called ocean acidification. By the year 2100, the sea surface pH is predicted to drop by up to 0.4 units. This may not seem much, but it has been shown to significantly affect the fitness, physiology, reproduction and behaviour of everything in the sea from huge sharks and whales to the tiniest of plankton.

Continue Reading.

  • Kingdom: Animalia
  • Phylum: Chordata
  • Taxon: Cephalochordata

Lancelets are small, invertebrate marine organisms that are unique in that the notochord (skeletal rod) extends beyond the anterior end of the dorsal nerve tube. These suspension feeders burrow into shallow sediments with just the head protruding. Seawater enters the pharynx and passes through the pharyngeal slits where food is filtered and passed to the intestine. 

Photograph from:


Marine aliens by Adolf Schaller, from Terence Dickinson’s Extraterrestrials: A Field Guide For Earthlings. Convergence is a big theme here, environmental pressures dictating superficial similarities to terrestrial forms.