‘Stars,’ Snails and Toxic Tuna

February 18, 2015

seastarOvercast with a damp ground fog this early Wednesday on California’s north coast, the weather pattern down to a science.
Preliminary rainfall totals for January are out from the NWS, and for my area, we were about 25 percent of normal — I thought we were dry as a bone, but seemingly not, maybe the heavy-dousing at the end of the month from those ‘atmospheric river’ storms made the difference.

One positive (kind of) item this morning in the world of nature is appearance maybe of an end to a devastating “melting” disease that’s decimated the sea star, ‘star fish,’ population on the US/Canadian Pacific Coast this past year or so, even here along the Humboldt County shoreline. Now maybe, at least in one area, there seems to be a re-bounce — Indian Island in Port Townsend Bay, northwest Washington state.
Yesterday, from Seattle’s The Stranger:

Indian Island’s sea star population—like other sea star hangouts up and down the West Coast—experienced a swift and mystifying die-off that inspired alarmist headlines in 2014.
Marine biologists looked on with horror as appendages of the keystone species—a species that plays a fundamental role in its ecosystem — washed ashore.
But this year, Barsh and his crew found something hopeful: hundreds of sea stars, babies, mostly. And healthy, from the looks of it.
The discovery, which other sea star monitoring sites have also documented, is a big deal.
Barsh and his colleagues, a scrappy team of conservationists who have been hyper-focused on Salish Sea ecology since 2006, were specifically looking to see whether Indian Island’s sea star population would make a comeback. To some extent, it did.
“At this point, at worst we’re at less than 1 percent morbidity, no bits and pieces [of sea stars] like we saw last summer,” Barsh told me after the January survey.
“Now the question is how many of the little guys we’re seeing will be lost to predation and disease this year.”

That’s the other mystery afoot.
Despite a major report identifying a possible culprit of sea star wasting disease late last year, scientists still don’t really know what caused the sea star deaths.
In November, a national research team (including Raimondi) published a study showing that sick sea stars carried something called a densovirus, a malady typically found in arthropods (like insects and crustaceans).
The researchers found that viral tissue from sick sea stars injected into healthy ones got the healthy ones sick. At the same time, they also discovered that the virus has existed in what were thought to be healthy sea stars going as as far back as 1923.

Ian Hewson, a Cornell University ocean microbiologist and lead author on the densovirus study, isn’t ruling out environmental causes, either.
“Certainly the oceans are warming and acidifying, no question about it,” Hewson said.
But there’s not a clear correlation between sea star wasting and warming temperatures, he added even though warmer temperatures make sea stars more stressed out.
Researchers haven’t yet looked into how ocean acidification could affect sea stars’ susceptibility to the virus, and it’s difficult to replicate conditions that would stress out sea stars in a lab.
“We’re calling it one disease, but it’s probably a set of symptoms that can be linked to many things,” Hewson said.
“I’m not discounting the possibility that there’s some unmeasured environmental factor in this disease.”

And that ‘unmeasured environmental factor,’ of course, is global warming.
In a much-related subject, ‘ocean acidification,’ we now have the ability to actually witness the fallout from all the CO2 that’s been belched — and to be belched — into the air and then sucked down into the salt waters of the earth. Satellite technology can bring it home.
From Climate Central yesterday:

The depressing task of monitoring ocean acidification just got a little easier.
A collection of scientists from Europe, the U.S. and India have developed a technique that could provide the first global and nearly real-time assessment of our rapidly acidifying seas.

Oceans are taking in about 90 percent of the excess heat created by human greenhouse gas emissions, but they’re also absorbing some of the carbon dioxide (CO2) itself.
According to the European Space Agency, about a quarter of all human CO2 emissions are being taken in by the world’s oceans.
A complex set of chemical processes dissolves that CO2 and turns it into carbonic acid,  which dissolves shells and coral, creating a cascade effect that could disrupt entire marine ecosystems.
The current rate at which oceans are acidifying has been unseen in 300 million years and the consequences could be costly.

Oceans on acid, causing some bad, ugly flashbacks. And with pulsating colors, too — check out the link.

This morning, too, another odd, but related subject of the deep, blue sea, and despite all the acidic Orange Sunshine, a new interesting/important discovery found in a tiny, tiny aquatic snail.
From ScienceRecorder:

Researchers in the U.K. find that the teeth of a class of aquatic snails are made of the strongest biological material ever studied.
The name “limpet” is a common name for aquatic snails possessing shells that lack any obvious coiling architecture.
All limpets fall into the Gastropoda class of mollusks.
Their conical shells are described as “patelliform,” or “dish-shaped.” Limpets live on tidal rocks and feed on algae and sea weed during high tide.
When the tide moves out, they hunker down in small depressions that they carve for themselves in the rock, specific territories called “home scars.”
But how do the inconspicuous little creatures create these home scars?
It turns out that they have on their tongues, called radulae, tiny teeth that they use to scrape away at the surface of the rock on which they dwell.
These teeth are made of a protein-mineral composite material that exhibits extraordinary strength.
The teeth are stronger than spider silk and all but the very strongest man-made materials.

The limpet tooth material is stronger than Kevlar and almost as strong as the highest quality carbon fiber material available today.

Snail-mail that one.
Finally, and also further related, in a story on Monday from The Conversation and another red-flag/warning:

My colleagues Carl Lamborg, Marty Horgan and I analyzed data from over the past 50 years and found that mercury levels in Pacific yellowfin tuna, often marketed as ahi tuna, is increasing at 3.8 percent per year.
The results were reported earlier this month in the journal Environmental Toxicology and Chemistry.
This finding, when considered with other recent studies, suggests that mercury levels in open-ocean fish are keeping pace with current increases in human-related, or anthropogenic, inputs of mercury to the ocean.

Other-than-that, everything’s cool…

(Illustration above: ‘A common starfish on Trinidad State Beach,‘ found here).

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