Ocean-science

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Invisible Ocean: Plankton and Plastic, A Short Documentary About a Microscopic Threat to Ocean Life

INVISIBLE OCEAN: PLANKTON AND PLASTIC, directed by Emily V. Driscoll, is an award-winning short documentary that follows NYC sci-artist Mara G. Haseltine as she creates a sculpture to reveal a microscopic threat beneath the surface of the ocean. 

During a Tara Oceans expedition to study the health of the oceans, Haseltine discovered microscopic pieces of plastic inside samples of tintinnid plankton. The discovery inspires her to create a sculpture that shows that the microscopic ocean world affects all life on Earth.

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The Mesozoic Park: Spinosaurus

Common name: Spinosaurus (SPINE-oh-SAWR-us) Size: 12-15m (40-50ft) long Age: Mid-Cretaceous (97.5-95 million years ago) Geographic range: North Africa Liked: swimming, being huge, and eating everything Disliked: running Taxonomy: Animalia > Chordata > Saurischia > Spinosauria > Spinosaurus > S. aegyptiacus

Unlike genera such as mosasaurus, pliosaurs, etc., which are considered aquatic REPTILES, the Spinosaurus was the only known aquatic dinosaur. The difference between them is that a “dinosaur” is defined as a terrestrial, biped/quadruped with a diapsid skull. The aquatic reptiles are not considered dinosaurs because they only swim, while the Spinosaurus was a dinosaur that was terrestrial, but would swim to catch fish.

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First (Fully) Warm-blooded Fish Found

by Stephanie Pappas

The car-tire-size opah is striking enough thanks to its rotund, silver body. But now, researchers have discovered something surprising about this deep-sea dweller: It’s got warm blood.

That makes the opah (Lampris guttatus) the first warm-blooded fish every discovered. Most fish are exotherms, meaning they require heat from the environment to stay toasty. The opah, as an endotherm, keeps its own temperature elevated even as it dives to chilly depths of 1,300 feet (396 meters) in temperate and tropical oceans around the world.

“Increased temperature speeds up physiological processes within the body,” study leader Nicholas Wegner, a biologist at the National Oceanic and Atmospheric Administration (NOAA) Fisheries’ Southwest Fisheries Science Center in La Jolla, California, told Live Science. “As a result, the muscles can contract faster, the temporal resolution of the eye is increased, and neurological transmissions are sped up. This results in faster swimming speeds, better vision and faster response times.”…

(read more: Live Science)

photograph by NOAA Fisheries, SW Fisheries Science Center

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The unstoppable glaciers of Antarctica


In the last few decades, glaciers in western Antarctica have been flowing out to the ocean at a faster rate.  Researchers from NASA and UC Irvine have been observing the glaciers in this area with 40 years of satellite data and have concluded that they’re melting at an unstoppable rate.

The issue lies in the fact that as a glacier moves faster to the ocean it thins out. This makes it lighter and able to float easier on water.  So a larger area of the glacier is touching the warming currents of the ocean.  This becomes a multiplying effect: more of the glacier melts at a faster rate. 

The dangers of this is that these glaciers contribute to a large percentage of sea level rise and in just two hundred years could raise the sea level by four feet.

Tune in TOMORROW, Thursday March 26, for a Smithsonian webcast titled Ocean Biodiversity - Discovering Marine Invertebrates, airing at 11 a.m. and 2 p.m. EDT on the Q?rius website. Dr. Karen Osborn, an invertebrate zoologist at the National Museum of Natural History, will appear live to discuss and answer questions. 

When we think about the ocean, we may visualize sea turtles swimming around coral reefs, sea urchins anchored in tidepools, dolphins breaching the surface, or even shrimp gathered around deepwater sulfur vents. But most of the ocean is just open water, miles and miles of it from below the surface to thousands of feet down. This ocean midwater is the largest habitat on Earth! 

Yet midwater habitat has not been well-studied because it is difficult to explore. It’s mostly cold, dark, and under high pressure. Some of its most surprising secrets are animals without backbones (invertebrates), such as worms and jellies, that come in a variety of weird colors and shapes. Many of these midwater species have never been recorded by science, challenging scientists to figure out what they are.

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The by-the-wind-sailor or vellela vellela is not a jellyfish, but a colony of polyps which cohabitate. The polyps have various functions: eat, reproduce, deterrence. Together, they form an oval disk, which drifts on the waves. The by-the-wind-sailor has a triangular sail on this round disk. Using its sail, this organism travels the world seas.

via: eol.org // Photo 1: Pouringwaffles // Photo 2:  NOAA 

South Africa’s Sardine Run

(Source)

  • What is the Sardine Run?

The Kwazulu-Natal Sardine Run is honestly one of the craziest and greatest shows that Mother Nature has given us. It starts in early May along the southern coasts of South Africa, and runs through the beginning of July. During that time, billions of sardines (Sardinops sagax) congregrate in the cool waters of the Agulhas Bank, which is the ocean region where the warm Indian Ocean water meets with the cold Atlantic Ocean waters. 

Sardines spawn in those waters, and then start migrating northward along the east coast of South Africa (the Kwazulu-Natal region) up to Mozambique. Some scientists have estimated that the sardine run rivals the great wildebeest migration of eastern Africa (in Kenya and Tanzania) in terms of biomass. 

(You can see the mixing of hot waters from the Indian Ocean with the colder waters of the Atlantic. This convergence leads to treacherous sailing conditions, but it also fuels the nutrient cycle for marine life, making it one of the best fishing grounds in South Africa. Source)

The sheer number of sardines thus create an incredible feeding frenzy for birds, whales, dolphins, game fish, bronze whalers and many other shark and fish species. Of course, the local fishermen are also trying to catch as many sardines as possible for their own livelihood. The shoals may exceed over 7km long, 1.5km wide, and 30m deep! It is an open buffet for everybody. 

Check out the insanity that is the Sardine Run underwater. Sadly this video is not mine, as I was only able to witness this migration event from the shore (the winter sea conditions were a bit too rough for us to go out), but it was already crazy to see from the beach, and I hope to return someday to be able to dive and witness it first hand.

(Whales arrive to the party at around the 12:00 minute mark)

The run is crucial to the local economy, not only for food and the fishing industry, but also for tourism, as many divers and freedivers fly down to South Africa to dive and witness the migration. Needless to say, you need to be pretty comfortable with your diving skills before they let you be in the middle of the bait ball. 

  • Why do sardines ‘run’? 

I am sure now you are all wondering why do the sardine brave such dangers and repetitive, intense predation year after year? Like a lot of things within this field of study, well… scientists aren’t quite sure yet!

From an ecological perspective, the whole phenomenon remains a bit misunderstood, and many theories exist, that sometimes contradict one another. The latest theory is that it might be due to a combination of a seasonal reproductive migration of a genetically distinct subpopulation of sardines, along with their preferences for colder waters. 

The sardines like water temperatures below 20C (68F). In winter—June and July in the southern hemisphere—the surface water cools along the east coast, allowing the sardines to expand their habitat and move up north. 

(Open buffet for everybody; sea birds do not hesitate to dive in for such an abundant meal. Gannets can dive down to 20m! Source)

Sometimes, this phenomenon does not happen. The conditions have to be ideal for the migration to take place, and the water has to be cool enough, preferably below 21C (70F) for the sardines to ‘run.’ Some years, it does not happen at all. 

Favorable migration conditions include cooling sea surface temperatures, calm current conditions, light north-westerly land breezes, calm atmospheric conditions and the large presence of predators inshore such as common dolphins, Cape gannet, and an increased number of sharks and game fishes.

(When whales join the feast, it truly become a magnificent event. Source)

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Divers often describe the experience of swimming beneath a manta ray as like being overtaken by a huge flying saucer. This ray is the biggest in the world but is a harmless consumer of plankton and small fish. When feeding it swims along with its cavernous mouth wide open, beating its huge wings slowly up and down. 

On coral reefs, manta rays tend to congregate over high points where currents bring plankton to them. They are considered to be “sociable” with divers in some sites, and has been known to “dance” with them. 

Source: Ocean //  Photo 1 : The Sun // Photo 2: Mantaray.com

Glowing Sky, Glowing Water

Over the last week, the island of Tasmania has seen its southern shores glowing. The lower blue glow is produced by dinoflagellates – a type of single-celled organism common throughout the ocean that gives off light through a chemical reaction. This species tends to light up when it is disturbed, whether by action of humans or simply by the waves. When they suddenly grow in an area in large amounts, they can be washed ashore, causing a glowing line along the bach.

There are many bioluminescent species in the ocean – deep in the ocean that can be the only source of light – and the exact color of light given off by each varies slightly depending on the exact chemistry used. Pale blue hues like these are particularly common as blue light travels farther than more reddish light through water.

This pale glow was captured beneath the glow of another light – the Milky Way galaxy – by James Garlick – and shared on our wall with permission. Thanks!

-JBB

Image credit: http://on.fb.me/1Pxiqo4
The Photographer’s page (prints available if you contact through there):
https://www.facebook.com/JamesGarlickPhotographer

Read more: http://bit.ly/1KkkX1b

Millions of deep-water fish die every year because of barotrauma, a condition divers know as “the bends.” But scientists say descending devices can help fish survive a trip to the surface.

I heard this story this morning driving to work and I thought it was a pretty interesting concept. Rather than letting a fish they can’t keep (due to size regulations, for example) die, fishers now have the technology to bring the fish back down to its original depth, and to hence help maintain healthy populations of that species… What a great example of how to involve all stakeholders and members of the community into ocean conservation.