THE STORY OF BLUEFIN TUNA

Infographic by the Pew Environment Group on the fate of Atlantic bluefin tuna—why the decline and what's needed for the species to recover. Living proof that really good-looking informative graphics will spontaneously broadcast spawn. For a metric version, click here.

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PLENTY MORE FISH IN THE SEA?

Visualization from Information is Beautiful based on data from the paper Hundred Year Decline of North Atlantic Predatory Fishes comparing fish landings in tons per square kilometer in 1900 versus 2000 for popularly eaten fish—bluefin tuna, brill, cod, haddock, hake, halibut, herring, mackerel, pollock, salmon, sea trout, striped bass, sturgeon, turbot, whiting.
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Via Information is Beautiful.

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MADE IN THE OCEAN: SHRIMPS

Crazy crustacean design.

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Cleaner shrimp (Lysmata amboinensis). Credit: Lonnie Huffman via Wikimedia Commons.

Fire shrimp (Lysmata debelius). Credit: Haplochromis via Wikimedia Commons.

Armed nylon shrimp (Heterocarpus ensifer). Credit: NOAA Ocean Explorer.

Snow-capped shrimp (Periclimenes venustus). Credit: Richard Ling via Flickr.

Harlequin shrimp (Hymenocera picta). Credit: Chad Ordelheide via Wikimedia Commons.

Unidentified shrimp. Credit: David Burdick / NOAA via Flickr.

Pederson's clearner shrimp (Periclimenes pedersoni). Credit: Becky A. Dayhuff / NOAA via Flickr.

Sea star shrimp (Periclimenes soror). Credit: Richard Ling via Flickr.

Pregnant anemone shrimp. Credit: rtonyr via Flickr.

Pederson's cleaner shrimp (Periclimenes pedersoni). Credit:
LASZLO ILYES via Wikimedia Commons

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ENDING OVERFISHING

The problem, a solution, animated.
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CROCHETED CORAL REEF AND OTHER WONDERS ANIMATED

Spawning corals and sparring starfish. Insanely creative video.
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"Bounce Bounce" by Hilary Hahn and Hauschka from Hayley Morris on Vimeo.

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A GLOBAL WARMING REFUGE AT EQUATORIAL ISLANDS

Some islands in the bulls'-eye of climate change may dodge the worst thanks to heretofore unknown dynamics between deep currents, upwelling, and rising temperatures.
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Gilbert Island archipelago in the Pacific island nation of Kiribati. Credit: NASA/Aqua Satellite.

  
A new paper in Nature Climate Change reports on an unexpected refuge of cooler water around the equatorial Gilbert Islands—one of three archipelagos of the Pacific island nation of Kiribati (say: KEER-uh-bus).
  
This is good news at a time when when scientists predict that rising ocean temperatures in the equatorial Pacific will wreak havoc (coral bleaching, coral disease) on coral reef ecosystems by the end of the century. 
  
The new study shows that climate change could cause ocean currents to operate in a surprising way to mitigate warming near a handful of islands on the equator... which may then become isolated refuges for corals and fish.
    

The three archipelagos of the Pacific island nation of Kiribati straddle the Equator. Map based on: TUBS via Wikimedia Commons.

  
The dynamics of this cooler-water refuge include:
  

1. Equatorial trade winds pushing a surface current, the Equatorial Countercurrent, from east to west
2. A swift Equatorial Undercurrent flowing below the Equatorial Countercurrent in the opposite direction, west to east, at 100-200 meters (328-656 feet)

Where the Equatorial Undercurrent encounters an island, its flow is deflected upward on the island's western flank, carrying its cooler nutrient-rich water to the sunlit surface and creating localized areas of greater ocean productivity.

You can see the dynamics of this in the map and graph below showing chlorophyll levels—a marker of phytoplankton and hence marine productivity—across the equatorial Pacific. The red in the map view indicates highest chlorophyll / phytoplankton / marine productivity.

Credit: Kristopher B. Karnauskas and Anne L. Cohen. Nature Climate Change. DOI:10.1038/nclimate1499.

    
Clearly, the most productive waters occur in the eastern tropical Pacific, where the Equatorial Undercurrent drives up against the Galapagos Islands to create huge upwelling.
  
Chlorophyll quantities then dwindle rapidly as you move west... until the anomalous red signature marking the outlines of the Gilbert Islands of Kiribati seen inside the white-dotted rectangle. The islands are not shown in the map view, just their chlorophyll signatures.
  
Co-author Anne Cohen at WHOI says:
  

"Global models predict significant temperature increases in the central tropical Pacific over the next few decades, but in truth conditions can be highly variable across and around a coral reef island. To predict what the coral reef will experience in global climate change, we have to use high-resolution models, not global models."

Coral reef of the equatorial Pacific. Credit: USFWS.

The models predict:
  

• That as air temperatures rise and equatorial trade winds weaken, the Pacific surface current will also weaken by 15 percent by the end of the century.
• But the then-weaker surface current will also impose less friction and drag on the EUC, so this deeper current will actually strengthen by 14 percent.

 
The high-resolution models developed by  Kristopher Karnauskas, also at WHOI, and Cohen, suggest the amount of upwelling will actually increase by about 50 percent around the Gilbert Islands, to reduce the rate of warming waters there by about 0.7°C (1.25°F) per century.
  
From the paper:

In the central Pacific, home to one of the largest marine protected areas and fishery regions in the global tropics, sea surface temperatures are projected to increase by 2.8 °C by the end of this century. Of critical concern is that marine protected areas may not provide refuge from the anticipated rate of large-scale warming, which could exceed the evolutionary capacity of coral and their symbionts to adapt. Combining high-resolution satellite measurements, an ensemble of global climate models and an eddy-resolving regional ocean circulation model, we show that warming and productivity decline around select Pacific islands will be mitigated by enhanced upwelling associated with a strengthening of the equatorial undercurrent. Enhanced topographic upwelling will act as a negative feedback, locally mitigating the surface warming. At the Gilbert Islands, the rate of warming will be reduced by 0.7±0.3 °C or 25 ± 9% per century, or an overall cooling effect comparable to the local anomaly for a typical El Niño, by the end of this century. As the equatorial undercurrent is dynamically constrained to the Equator, only a handful of coral reefs stand to benefit from this equatorial island effect. Nevertheless, those that do face a lower rate of warming, conferring a significant advantage over neighbouring reef systems. If realized, these predictions help to identify potential refuges for coral reef communities from anticipated climate changes of the twenty-first century.

  

A bathymetric view of the Phoenix Islands group of the Pacific islands nation of Kiribati. Credit: Phoenix Islands Protected Area.

    
As an interesting aside, in 2006 Kiribati created the Phoenix Islands Protected Area (PIPA) to the east of the Gilbert Islands. In 2008 they doubled its size to make it the world's largest marine protected area. (Since then the Chagos Marine Reserve in the Indian Ocean has surpassed PIPA in size.)

At 410,500 square kilometers (158,453 square miles), about the size of California, PIPA preserves one of the Earth's last intact oceanic coral archipelago ecosystems, complete with eight coral atolls, two submerged reef systems, underwater sea mounts, and abundant marine and bird life.
 
This is a truly phenomenal accomplishment. 
  
But if the Gilbert Islands are destined to become one of the few places where coral reef biodiversity is able to hang on in the coming century, then maybe we should begin thinking about giving those waters stronger protections too.

 

An atoll of Kiribati. Via Flickr.

The paper:
   

• Kristopher B. Karnauskas & Anne L. Cohen. Equatorial refuge amid tropical warming. Nature Climate Change (2012) DOI:10.1038/nclimate1499

  

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OYSTER EGGS

And other resurrections...
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Spawning oysters. Via.

Spawning sponge. Via.

Spawning corals. Via.

Spawning horseshoe crabs. Via.

Spawning squid. Via.

Spawning sea star. Via.

Spawning aggregation of devil rays. Via.

Spawning reef fish. Via.

Check out my earlier post Sea Eggs.

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SPRING BLOOM

Spring bloom from Rafa Herrero Massieu on Vimeo.

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CRAB GETS CRAFTY

Hermit crab with anemone n shell. Credit: mirtai via Flickr.

My recent hermit crab post included a video of hermits trying on new homes, and included the the way some defend their shells with stinging anemones (above).
  
But I also found myself wondering what will become of hermit crabs in a world of increasing ocean acidity and dwindling seashells? (You can read more about that in my latest article in OnEarth magazine.)
  

Credit: Courtesy of the NOAA Pacific Marine Environmental Laboratory. 

In the above image you can see the fate of a shell dissolving over 45 days in acidified water. 

   

Now via Discover Magazine I see this interesting photo (below) of a nude hermit crab donning an anemone: 

Greg Rouse and colleagues found this critter during an expedition off the coast of Costa Rica in 2010. The area is lacking in large snail shells, says Dr. Rouse, and there has been a previous report of this species, Parapagurus foraminosus, covered by an anemone.

  

Credit: Greg Rouse, Scripps Institution of Oceanography at UC San Diego.

Crabs—survivors since at least the early Jurassic—are crafty!

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COWRY POWER

Via.

  
My mother always told me to carry a cowry shell in my wallet for good luck. Since she comes from India, I began to wonder about the roots of this belief.
  
We know that cowry shells are the longest-lived and most widely-spread currency of our species—in use perhaps as early as 4,000 years ago, and important to cultures ranging from Oceania to West Africa and most everything in between.

  

Credit: Bin im Garten via Wikimedia Commons.

  
They've been found in association with coins from sites in India dating to the first century AD according to the Conchological Society of Great Britain and Ireland.
  
But they seem to have been used even earlier in ancient China. Here's an excerpt from an interesting paper by Colin Narbeth:
  

The use of cowry shells as a medium of exchange goes back to the dawn of Chinese civilization. One of the earliest written references is that of an historian, Ssu-ma Ch'ien, of c. 145-86 BC. He mentions cowries as being used as money in the Shang and Chou periods. In the Shang Dynasty [1766-112BC] the character PEI was part of the Chinese language. The earliest form, the archaic script which developed into Seal Script, was merely a rough picture of the ventral side of a cowry [貝]. It was so important that PEI was adopted as one of the 214 radicals—the foundations characters of the language. Today 84 Chinese characters have PEI as the main foundation. Finds of cowry shells, sometimes in very large quantities, have come to light in tomb excavations and the opinion of most Chinese archaeologists today is that they were there as money.

There were times the Chinese couldn't get enough shells and manufactured them from wood, stone, bone, bronze, gold, silver, jade, and other semi-precious stones. 
  
The first metal currency was actually imitation cowry shells.

  

Copper/bronze imitation cowry shell money. Via.

Stone imitation cowry shell money. Via.

Pottery imitation cowry shell money. Via.

The species most commonly used as currency—the money cowry—was named by the father of modern taxonomy Carl Linnaeus as Cypraea moneta in 1758. 
  
Today's scientific name is Monetaria moneta.
  

Live money cowry. Via.

They were collected in vast numbers from the waters around the Maldives Islands off southern India. More from Colin Narbeth:

From the Arab merchant Sulayman (851 AD) we learn that at one time, in the 9th century, the Maldives had a very beautiful and wealthy Queen. Having used up her Treasury of cowries she resorted to sending the Maldive maidens to collect large palm leaves from the coconut trees. These were then laid in the shallow water. Soon thousands of cowries would crawl onto the leaves—to be suddenly pulled out of the water and left high and dry to die before being sent to replenish the Queen’s Treasury. This account was confirmed by Masudi of Baghdad, famous Arab historian of the 10th century.

In the 17th century Pyrard de Laval was wrecked on the Maldive Islands and stayed there for two years. He wrote: "They called them (cowries) Boly and export to all parts an infinite quantity, in such wise that in one year I have seen 30 or 40 whole ships loaded with them without other cargo. All go to Bengal for there only is there a demand for a large quantity at high prices. The people of Bengal use them for ordinary money although they have gold and silver and plenty of other metals; and what is more strange, kings and great lords have houses built expressly to store these shells and treat them as part of their treasure."    

   

Modern Maldives currency with cowry shell design. Via Wikimedia Commons.

As you might imagine, with so much pressure on the stocks, Monetaria moneta eventually became scarce in Maldivian waters. Attention switched to a similar species, Monetaria annulus. From Narbeth:

These could be found in huge quantities off the Zanzibar coast... By 1851 inflation was undermining the trade. Cowries were so plentiful and so cheap that counting them became a very time consuming matter. Town governors packed them in sacks—20,000 to the sack. But when used between private individuals they had to be counted, in fives. Barth wrote: "The general custom is to count them in fives, in which operation some are very expert, and then to form heaps of 200 or 1000 each. The counting of 500,000 shells is a really heroic work."

Credit: Sarah Starkweather via Flickr. 

   
My mother and her kin came from Bengal. So perhaps the habit of carrying a cowry shell in your wallet as good luck—specifically, as monetary good luck—is left over from the time when cowry shells were real money.
  
Interestingly, Narbeth writes about periods of transition in China when rulers tried to abolish cowry currency in favor of a metal currency, only to have the next ruler abolish the upstart metal in favor of cowry currency. 
  

Cowry eggs. Via.

In times of such uncertainty, it might have been a good idea to keep some cowry power in your wallet. Just in case it got valuable again. 
  
I'm still doing it.

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