Archive for September, 2015

Sep 1 2015

How Many Fish in the Sea? Genetic Testing Could Answer That

Today, divers do marine surveys underwater, counting each organism they find.
Today, divers do marine surveys underwater, counting each organism they find. (National Park Service)

Advances in genetic testing have revolutionized everything from health care decisions to crime forensics. Now, the technology may help protect marine life off the California coast.

In the waters of Monterey Bay, DNA sequencing is allowing biologists to study fish and whales without ever having seen them.

Just a sample of seawater, the volume of a water bottle, is enough to reveal what marine life has been swimming through that part of the ocean. The technique could improve marine monitoring, where scientists track an ecosystem year after year to gauge how it’s doing.

One Fish, Two Fish

Taking a marine census today requires hours of field time, either with scuba diving or boat trips.

“It gets a little challenging because you’re floating, you’re swimming, you’re looking, you’re counting,” says diver Dan Abbott, unloading his scuba gear on a beach in Monterey.

He’s holding a waterproof clipboard, on which he’s tallied all the fish and marine life he saw in a kelp forest just offshore.

“About 150 fish in all. Pile perch, black perch, blue rockfish, kelp rockfish,” he says, just for a start. He’s diving with a team from Reef Check California, a group of volunteers that surveys this site twice a year.

The group’s data help answer a question that’s key to California’s conservation efforts: are there more fish here now than there were eight years ago?

That’s when this kelp forest became part of a massive experiment to restore marine life in California. It was set aside as a marine protected area, where there’s little or no fishing allowed.

There are now more than a hundred protected areas up and down the coast, covering 16 percent of state waters. The idea is that marine life will slowly recover there, improving the ecosystem both inside and outside the boundaries of each area.

The only way to know if these areas are working is through underwater surveys, repeated year after year. In 2013, biologists reported encouraging results in the protected areas off the Central Coast.

Field surveys are expensive. The state supplied $16 million for monitoring studies, and the funding has already run out in some regions of the coast. Monitoring has continued, thanks to universities, foundations and volunteer groups.

Studying the Ocean Without Getting Wet

“It’s been amazing what we can detect in just a liter of seawater,” says Jesse Port, an environmental genomicist at the Center for Ocean Solutions at Stanford University.

He points to a rack of one-liter Nalgene water bottles that he uses to take seawater samples from the kelp forests in Monterey Bay. The rest of the work happens in the lab with a technique known as “environmental DNA” or eDNA.

“So all organisms shed their DNA,” he says. “Their skin, their scales, their waste – all of this gets into the water. You can think of it as a soup of genetic information.”

Port filters the seawater to collect all the cells. Then, he weeds out the algae and plankton and sequences the DNA of all the vertebrates, like whales, seals, and fish.

“We get, with the machine we’re using, 150 million sequence reads for a given sequence run,” he says, “and that’s a lot of information.”

Those gigabytes of results require heavy data-crunching, but eventually, he ends up with a spreadsheet that tells him what organisms were found.

The approach is possible because DNA sequencing has gotten so much cheaper. One sample costs just $1,500.

“This was just not possible five, ten years ago,” Port says. “And sequencing technology is just going to get better, so this will probably get even cheaper.”

Finding Turkey Underwater

Port first ran DNA tests in one of the large tanks at the Monterey Bay Aquarium, which provided an easy test case because he knew exactly what was swimming there.

But he got back results he didn’t quite believe. “Things like turkey,” he says. “We picked up chicken DNA in these tanks.”

Turns out, poultry was in the feed some of the fish were getting. But it raised some big questions. How do you know whether the DNA comes from a fish or from something it ate miles away? Or how do you know the DNA didn’t float in on a current?

Port is still working on the answers to these questions and he’s doing studies to ground truth his results, checking them against what scuba divers find. But if the technology proves itself in the ocean, it could revolutionize how marine monitoring is done.

“You can cover such a larger area by taking water samples,” he says, “rather than having divers do that all themselves.”

Paul Michel, the superintendent of the Monterey Bay National Marine Sanctuary, says they’re already using eDNA testing to help assess species diversity in the sanctuary.

“Absolutely, we did DNA testing on a research cruise in May,” Michel says, “and at each stop on the way, we were taking water samples. We can compare the DNA results to other types of samples over time.”

Eventually, it doesn’t even have to be humans taking those water samples.

MBARI's long-range autonomous underwater vehicle can remain at sea, unattended, for weeks at a time.
MBARI’s long-range autonomous underwater vehicle can take samples at sea, unattended, for weeks at a time. (Todd Walsh (c) 2010 MBARI)

DNA Lab at Sea

“What this is, is a microbiology lab that exists out in the ocean,” says Jim Birch of the Monterey Bay Aquarium Research Institute, pointing to a 10-foot yellow tube. It’s called a long-range AUV, or autonomous underwater vehicle.

It looks like a torpedo, but it’s actually a robot, containing a miniature DNA lab called an Environmental Sample Processor.

The robot cruises along underwater, taking samples and analyzing them onboard. Birch recently sent it out for a test run in Monterey Bay.

“I was sitting in my living room with my computer open and there in front of me was the control panel for the AUV,” he says. “And I could direct it to go to a new place and it was just this surreal feeling.”

When the AUV finds an organism it’s looking for, it surfaces and calls home, pinging a satellite or cell phone network with the data, and giving scientists an almost real-time snapshot of the ocean.

Currently, it only tests for one thing at a time, like algae or plankton, and Birch says there’s more engineering work to be done before the AUV gains widespread use.

“This is going to be transformative in oceanography,” he says. “You don’t have to be out there on a boat with a huge crew, spending all this money.”

A change that could help the state’s conservation funding go farther, ensuring California’s marine protected areas are working.

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Sep 1 2015

NASA: Rising Seas About to Catch Up With the West Coast

Screen-Shot-2015-08-26-at-3.31.32-PMNASA Animation shows the wide variance in sea level rise in recent years. The pale coloration along the West Coast illustrates a lower rate of rise. (NASA Scientific Visualization Studio)

Rising Seas are about to become a bigger issue for the West Coast, according to scientists.

Using satellite and other data, NASA scientists have been tracking rising sea levels around the world. They say that natural cycles in the Pacific have been masking effects of sea rise for about the last 20 years. But that’s changing.

“In the next five or ten years, I think the west coast of the United States is going to catch up,” says Josh Willis, a climate scientist at NASA’s Jet Propulsion Lab in Pasadena. He says a major ocean phase known as the Pacific Decadal Oscillation is in the midst of a big shift.

For about the past two decades, the PDO, which Willis describes as “El Niño’s bigger, slower, brother,” was “piling up” warmer water on the far side of the ocean, exacerbating sea rise there. When water warms, it expands.

“So we’ve actually seen a slight drop in sea levels off of our coastline  because of the rearrangement of heat within the oceans,” Willis explains.

That rearrangement could mean an acceleration in the rate that seas rise long the West Coast, eventually overtaking the pace of sea level rise on the East Coast and elsewhere.

“We could be looking at rates in the eastern Pacific two or three times as high as the global rates in the coming years,” says Willis. “So we could be in for wild ride over the next 20 years or so.”

As KQED and San Francisco Public Press have reported recently, billions in shoreline development in the Bay Area are in the planning stages or already begun, despite scientists’ warnings about rising seas.

Scientists say the brewing El Niño will also pile up warm water along California, making coastal flooding that much more likely, very soon. The warm water along the Equator that largely defines El Niño is expected to rival or surpass the legendary “Godzilla” El Niño of 1997-98 in strength.

NASA says global sea levels have risen about eight inches since the beginning of the 20th century and more than two inches in the last 20 years. Though simple thermal expansion of the water accounts for about a third of the rise so far, climate scientists expect melting glaciers and ice sheets to play a much larger role in coming years.


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Sep 1 2015

A Giant Glob of Deadly Algae Is Floating off the West Coast

Cells of pseudo-nitzschia, a type of algae that’s producing neurotoxins in the Pacific.

From the air, the Pacific algal bloom doesn’t look like much of a threat: a wispy, brownish stream, snaking up along the West Coast. But it’s causing amnesia in birds, deadly seizures in sea lions, and a crippling decline in the West Coast shellfish industry. Here’s what you need to know about it, from what this bloom has to do with the drought to why these toxins could be a real threat to the homeless.

What’s causing it? The culprits are single-celled, plant-like organisms called pseudo-nitzschia, a subset of the thousands of species of algae that produce more than 50 percent of the world’s oxygen through photosynthesis. They’re a hardy variety usually found in cool, shallow oceans, where they survive on light and dissolved nutrients, including silcates, nitrates, and phosphates. “They’re sort of like the dandelions of the sea,” says Vera Trainer, who manages the Marine Biotoxin Program at the Northwest Fisheries Science Center in Seattle. “They’re always there in some low numbers, just waiting for nutrients to be resupplied to the ocean’s surface.” In most years, blooms in the eastern Pacific are contained near “hot spots” that dot the West Coast—relatively shallow and sheltered places like California’s Monterey Bay or the Channel Islands. They usually flare up in April or May as trade winds cycle nutrient-rich waters from offshore depths to the coast in a process called “upwelling,” but they fade after only a few weeks.

Why is it sticking around so long? The jury’s still out, but scientists are beginning to get a clearer idea. These past few years have been “incredibly weird” in the northeast Pacific, says Nate Mantua, a research scientist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center in Santa Cruz. He points to the same “ridiculously resilient ridge” of high pressure that’s been causing the historic drought in the western United States: This pressure also resulted in a pool of exceptionally warm water in the Pacific (known as “the blob”), with little weather to disperse it. Those conditions, along with prevailing winds and colder currents that ferry nutrients back to the coast, seem to be supplying the algae with a seemingly endless feast.

That makes the source of this bloom different from its cousin in the Gulf of Mexico, where fertilizers flowing from as far as Iowa are feeding a zone of algae that’s as large as New Jersey. “We’re seeing them in relatively pristine waters of the US West Coast,” Trainer explains, though she adds runoff and sewage discharge may be playing some role in the blooms off Southern California.

So just how big is this thing? Bigger than researchers have ever seen: a patchy stream that stretches from Southern California up along the Alaskan coast. The hot spot blooms that appear each spring are merging for the first time, Trainer explains. Though the combined mass has ebbed and flowed over the past four months, it hasn’t let up; her team finds algae each time they journey out to sea, with no signs of abatement soon. And it’s also unusually potent. “These are the highest levels of toxicity we’ve ever seen,” says Raphael Kudela, a professor of ocean sciences at the University of California-Santa Cruz. “It’s a truly extraordinary phenomenon.”

Levels of chlorophyll, viewed from space, indicate where algae is present in the waters of the Pacific. NOAA

How deadly are these “dandelions”? The algae produce a compound called domoic acid, a type of amino acid that leads to a condition commonly known as “amnesic shellfish poisoning” in humans. Shellfish and some small fish, like sardines and anchovies, feed on the algae and concentrate the toxin in their flesh. When animals further up the food chain—like birds—eat those fish and shellfish, the domoic acid seeps into the bloodstream and eventually the brain, where it attacks cells in the hippocampus, the brain’s command center for memory and learning. The result: amnesia-stricken birds that will repeatedly fly into windows, and sea lions that writhe on the shore, plagued by seizures. Both are symptoms of rapidly firing neurons in the hippocampus, which will eventually burn out and kill the animal. Beaches have been littered with dead fish, birds, and sea lions up and down the Pacific coast since May—all the way up to Alaska, where NOAA is investigating the deaths of fin whales in connection with the toxin.
Will it kill me? Probably not. Amnesic shellfish poisoning was discovered in 1987, when what was then a mysterious illness killed three people and sickened 105 more on Prince Edward Island, Canada. But cases since then have been rare. That’s due to a bevy of regulations that shut down recreational shellfish harvesting when toxicity spikes and require commercial shellfish operations to test each batch for toxins. Those moratoriums have cut into Washington’s $84 million crab industry, while a ban on recreational clam digging has hurt smaller, more remote communities, particularly in the Pacific Northwest. Trainer points to indigenous regions in coastal Washington, like the Quinault Indian Nation, where many members make ends meet by harvesting razor clams for healthy meals in the winter. Though fish are also tested, the toxins seep into their guts, which don’t usually find their way to the dinner table.
Researchers are also investigating what low levels of domoic acid can do to the brain over many years of exposure. Trainer cautions that the mild symptoms of low-level contamination mean most people wouldn’t be aware of the problem: “They might think they have a cold, or a little flu,” she says. Results from an ongoing inquiry into the effects of domoic acid on Native Americans in the Pacific Northwest have found evidence of memory and learning impairment, while studies in sea lions found antibodies for domoic acid, suggesting even low-level contamination can cause an adverse physiological response. Kudela also suggests that the homeless around Monterey Bay, where his team is located, could be looking to shellfish as a free meal, inadvertently exposing themselves to the toxins.

What happens next? Researchers are waiting for this fall’s big coastal storms, which should churn up waters and disperse the nutrients that allow the algae to thrive. Those systems should gather between late September in the Pacific Northwest and early winter in California. But from then on it’s harder to say. The “blob” could persist through or return after the El Niño expected this winter. But if it is strong enough, the El Niño could also lead to less predictable conditions come spring and even make another large bloom unlikely for years to come, explains Mantua, the NOAA climate scientist. That would make this current, extreme algal bloom look more like an anomaly than a new trend.

Still, even if the coast sees some relief from algae for the next few years, big changes can be expected in the coming decades as oceans warm worldwide. That could produce more hospitable conditions for algae and lead to different ecological threats, like red tides and dead zones, in the Pacific. “I think this is a window into the future,” Trainer says. “We can expect more of this to come.”


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