Ocean acidity from CO2 could violate EPA water standards by 2050

The acidification of the oceans is proceeding so fast that
the seas could violate Environmental Protection Agency
guidelines by the middle of the century.
That's the assessment of a multinational team of scientists
writing in the Sept. 25 issue of Geophysical Research
Letters.
But EPA water quality criteria are hardly the problem.
They're just paper and ink. The problem for us, said a
Hawai'i researcher who co-wrote the report, is what that
acidification could do to life around the Islands.
One key issue: the slowing growth of coral reefs that
protect many of our shorelines.
Richard E. Zeebe, an assistant professor in oceanography
with the University of Hawai'i's School of Ocean and Earth
Science and Technology, said the higher acidity could
decrease the rate of production of forms of calcium
carbonate like calcite and aragonite. (Calcium carbonate
is a base, and is eaten up by acidity.)
These compounds are the building blocks of coral reefs,
seashells and other forms of life—and they form much of
the sand on the beaches and the sea floor.
“Coral skeletons are made of aragonite, so it's likely
that calcification rates in corals will slow down with
potentially detrimental consequences for coral reef
ecosystem structure,” he wrote in an email.
How soon could there be issues?
“Given the response we see in experimental studies with
coral, it's likely that impacts are noticeable within a
few decades. Some coral studies indicate that
calcification rates could be reduced by about 50 percent
in 2050 relative to preindustrial values,” he wrote.
The paper in which Zeebe was a co-author argues that
“changes in ocean chemistry within the ranges predicted
for the next decades and centuries present significant
risks to marine biota.”
The increasing acidity is caused by the increasing amount
of carbon dioxide (CO2) in the atmosphere. One of the
other big results of this is global warming.
Before the Industrial Revolution, there were 280 parts
per million of carbon dioxide in the atmosphere. As
fossil fuels like oil and coal began forming the basis
of the world's energy supply, CO2 was a significant waste
product and ended up in the atmosphere.
Today, there's about 380 parts per million CO2 in the air.
And the researchers figure that at current rates of
fossil fuel burning, it could be 500 parts per million
by 2050 and 760 parts per million by 2100.
Lead author Ken Caldeira of the Carnegie Institution
Department of Global Ecology, 
said that about a third of the CO2 formed by fossil
fuel burning ends up dissolved in the oceans. He
explains the chemistry.
“When CO2 gas dissolves in the ocean it makes carbonic
acid, which can damage coral reefs and also hurt other
calcifying organisms, such as phytoplankton and
zooplankton, some of the most critical players at the
bottom of the world's food chain.
“In sufficient concentration, the acidity can corrode
shellfish shells, disrupt coral formation and interfere
with the oxygen supply,” he wrote.
Caldeira said that for the health of the planet,
atmospheric CO2 must not be allowed to exceed 500 parts
per million.
“We need to start thinking about carbon dioxide as an
ocean pollutant. That is, when we release carbon dioxide
into the atmosphere, we are dumping industrial waste in
the ocean.”
The researchers said the solution is conservation and
quickly changing to a global energy system that produces
very little carbon dioxide.
© 2007 Jan W. TenBruggencate 

How does sand move on or off a beach? In ripples.

Here's a question that likely never occurred to you: What role to the ripples in the sand on the sea floor play in the transport of sand?

Folks actually study that, and seriously.

(Photo: Ripples [with paw prints] just above the waterline at Virginia's Assateague Island National Seashore, Photo by Capt. Albert E. Theberge, NoAA Corps [ret.])

And in a time when most Hawai'i beaches are eroding, ripple science is a field of study that could help understand the processes at work.

Recent research on the subject, “Video-based observations of nearshore sand ripples and ripple migration,” was published in the Journal of Geophysical Research Vol. 112. The authors include J.M. Becker, Y.L. Firing, J. Aucan, R. Holman, M. Merrifield and G. Pawlak, and they conducted their study at Waimea Bay on O'ahu..

In clear, shallow water, it's easy to walk out into the sea and see the long, sinuous humps like lines of dunes on the sandy bottom. What may not be clear unless you conduct measurements, is that those sand lines are moving.

At some beaches, in smaller wave conditions, the sand ripples seem to move toward the shore, and the research team is finding that as the ripples move, so does the sand itself. In fact, “ripple migration may be an important mechanism for onshore sand transport during accretionary phases at Waimea Bay,” the scientists wrote.

Lead author Janet Becker, of the University of Hawai'i's Department of Geology and Geophysics, said ripples are dynamic. They change shape, orientation and size with different conditions.

For example, when they team worked at Waimea Bay, they found that the nearshore ocean sand ripples generally were parallel to the shore, but she said “ripples do change orientation with the direction of forcing,” by which she meant that for ripples created by waves, they change their alignment depending on the direction from which the swell was coming.

On one April morning in Waimea Bay, the team measured ripples with a wavelength of .8 meters. That means that from the peak of one ripple to the peak of another, it was about 31 inches.

Becker said that the wavelength of ripples can be associated both with the size of the grains of sand on the ocean floor, and with the wavelength of the waves passing over the bottom.

The scientists found that on that day, the ripples were moving at about a quarter wavelength in an hour toward the shore. That meant that each ripple moved about 8 inches an hour. That works out to about 16 feet per day.

The ripple itself represents sand moving from one part of the sea floor to another.

Most of the time, sand ripples are moving toward shore. But during big winter surf at Waimea, they can move away from shore.

“Large swell events cause significant beach erosion,” Becker said in an email.

Many beachgoers notice that big winter storms can suck the sand away from the shore at some beaches, while quieter summer conditions tend to replenish the beach. The researchers are trying to learn more about these patterns.

“We are looking at the time periods just following these (large swell) events to determine whether the recovery of the beach is aided in part by the shoreward migration of sand waves,” Becker wrote in the email.

The paper says that the team's work to date suggests that, in fact, it seems as if sand is being transported through the migration of the ripples—that during low waves, as ripples on the sea floor move shoreward, the sand is migrating in the same direction.

“Our preliminary results support this hypothesis, but we need to make field measurements to confirm that the migrating sand ripples really transport a significant fraction of sand,” Becker said.

“We hope to conduct an experiment on this during the winter on the north shore.”

© 2007 Jan W. TenBruggencate

Humpbacks invade Northwestern Hawaiian Islands

The Hawaiian humpback whale, whose population seems to be on a steady growth path since whaling for the species was stopped in 1965, appears for the first time to be moving in significant numbers into the Northwestern Hawaiian Islands.

(Photo: NOAA's Ark--Animals Collection)

The whale is one of the few success stories among endangered species. As Hawaiian forest birds like the po'ouli become rare and then go extinct, as Hawaiian monk seals decline in numbers despite significant efforts on their behalf, humpbacks appear to be thriving just by virtue of the fact that we've stopped slaughtering them.

Counts in the late 1970s suggested there were only a few hundred wintering in Hawai'i. Today, numbers are in the neighborhood of 4,000, and some suggestions are that they continue to increase at about 7 percent a year..

They clearly still have problems. They are crashed into and they crash into boats, they are chopped by propellers, they are entangled in buoys lines and fishing gear. But their numbers are on the increase. An active management program under the Hawaiian Islands Humpback Whale National Marine Sanctuary helps.

Until this year, they were believed to be centered on the shallow waters around Maui County, and spreading out to the Big Island and O'ahu and Kaua'i. But scientists never saw many of them in the 1,000 miles of islands, reefs, shoals and atolls to the northwest of Kaua'i and Ni'ihau.

It was assumed anything up there was just passing through.

Now, that's clearly not the case, according to a report in the Sept. 14, 2007, online posting of the Endangered Species Journal, “Identification of humpback whale Megaptera novaeangiliae wintering habitat in the Northwestern Hawaiian Islands using spatial habitat modeling,” by Dave Johnston, Marie Chapla, Lynne Williams and David Mattila.

“This is a significant find. We've seen humpbacks expand their use of the main Hawaiian Islands but were unaware that they also used the Northwestern Hawaiian Islands as wintering habitat,” said Mattila, science coordinator of the Hawaiian Islands Humpback Whale National Marine Sanctuary.

During a March 2007 scientific cruise into the islands, now protected as the Papahānaumokuākea Marine National Monument, the researchers conducted both visual surveys by trained observers scanning the ocean from the ship, and electronic monitoring by listening underwater for whale songs.

They got numerous hits using both techniques.

“The results of our habitat analysis and survey observations document for the first time the existence of extensive wintering habitat used by humpback whales in the (Northwestern Hawaiian Islands),” the authors wrote.

They detected mothers and calves, single whales, groups of whales, and they detected whales in most of the shallow areas through three-quarters of Papahānaumokuākea, from Nihoa all the way to Lisianski.

“It was quite surprising actually. Whenever we surveyed in shallow warm areas, we found humpback whales,” Johnston said.

Whales come down from the cold feeding waters of the arctic in winter, and while in the Hawaiian Islands, they seem to prefer waters less than 600 feet deep, and more than 70 degrees Fahrenheit in temperature. There's a fair amount of that kind of habitat in the main Hawaiian Islands, but there's more to the northwest. Only at the far tip of the archipelago—around Midway and Kure Atoll-- does it appear to be too cold for their winter comfort.

The fact that the whales can use those waters is good news for the whales. Not only is there twice as much habitat for them in those islands, but they're much less likely to run into boats, or have boats run into them—largely because there aren't many boats there.

It's bad news in that there is plenty of marine debris up there, and for most of the year, no one with the capability to disentangle them. Disentanglement teams with specialized equipment are generally available to whales in the main islands.

Papahānaumokuākea is managed by the U.S. Departments of Commerce and Interior, and by the State of Hawai'i. For a copy of the research paper see www.int-res.com/journals/esr. For more about humpbacks, see hawaiihumpbackwhale.noaa.gov/about/humpback.html. For more information about the marine monument see hawaiireef.noaa.gov or www.fws.gov/pacificislands.

© 2007 Jan W. TenBruggencate

Fisheries, and the problem with sharks

Longline fisheries catch and often kill stunning numbers of sharks.

(Photo: Southwest Fisheries Science Center, NOAA)

When squid was used for bait, half the catch of the Hawai'i swordfish longline fishery was sharks. The number dropped to 32 percent after fish replaced squid as bait.

The number is less than 25 percent in Australian and Fiji longline fisheries—a smaller number but still significant.

Why is that a problem?

"Sharks and their relatives are much more vulnerable to overfishing and population collapse than bony fishes. They grow slower, mature later and have lower population increase rates. Therefore, methods to manage them may have to differ from traditional fishery management methods,” said Eric Gilman, of the World Conservation Union.

Gilman is the lead author of a new report, “Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries: Industry Practices and Attitudes, and Shark Avoidance Strategies.”

The report was produced by the Western Pacific Regional Fishery Management Council, along with the United Nations Environmental Programme's Regional Seas Programme, Blue Ocean Institute, Consortium for Wildlife Bycatch Reduction, New England Aquarium, Project GloBAL (Global Bycatch Assessment of Long-Lived Species), and the Gordon and Betty Moore Foundation.

Researchers were from the United States, Japan, Australia, Peru, South Africa, Italy, Fiji and Chile.

The goal of the report was to learn from fishers themselves how best to reduce the unwanted catch of sharks.

A survey of captains found that you'll catch more sharks using squid for bait, using wire leaders that the sharks can't break, and fishing at certain depths preferred by sharks.

There are ways to reduce the shark catch, but they can have other impacts. For instance, if anglers use plastic leaders that sharks can cut, they will be less likely to put weights near the hooks, for fearing of losing both. That means the bait won't sink as quickly, and may be more likely to attract and hook seabirds.

There are fisheries where the sharks are an economic benefit. The boats keep the sharks and are able to sell them, and the revenue exceeds the cost of catching sharks. But in fisheries where shark take is either not valuable or not permitted by law, the costs of fishing in such a way that you catch sharks can be high.

In Hawai'i, as an example, it is illegal to simply take the shark fins and toss the rest of the shark back.

The costs of fishing in areas where sharks are caught can include damaged and lost gear, risk of crew injury in handling sharks, lost time in taking sharks off the gear, the lost opportunity to catch valuable species on hooks occupied by sharks, and so forth.

Veteran longliners are finding that they can adjust their fishing methods to increase their catch of the fish they want, and reduce their catch of sharks. More efficient fishing methods can include carefully selecting where to fish, specific times of fishing, leaving bait in the water for only limited amounts of time, fishing at specific depths and so on.

“Beyond these strategies, the state of knowledge to reduce unwanted bycatch and depredation by sharks in pelagic longline fisheries is poor,” the report said.

It proposes a number of new strategies, among them shark deterrents, which can include chemical, magnetic and electrical measures that may cause sharks to avoid fishing gear.

The study also notes, however, that there seem to be increasing markets for shark meat, meaning that sharks, instead of being troublesome bycatch, could become sought-after fish.

"Sharks are one of the world's most valuable fishery resources. They provide an important protein source, as well as a luxury item,” said Kitty Simonds, executive director of the Western Pacific Regional Fishery Management Council. The luxury item is shark fin soup.

And that increasing demand for their flesh a problem for the future of sharks, which as a group are long-lived, and which reproduce at low rates. Sharks thus are particularly vulnerable to overfishing, and will be slow to recover from it, the study says.

The world's fishery regulators thus will need to learn a lot more about the sharp-toothed predators, in order to protect them as fishing prey.

© 2007 Jan W. TenBruggencate

Pollutants collect on plastic marine debris

Crouch at the high-water mark on almost any Hawaiian beach and you'll find a kaleidoscope of color—not just the tans, greens and blacks of corals and volcanic stone, but also the whites, oranges, blues, reds and yellows that represent bits of plastic.

Scientists have long known that these are a mechanical problem for wildlife. That is, they fill the bellies of birds so they can't eat anything else and die.

But increasingly, it is becoming clear that they're also potentially a toxic problem—that toxic organic compounds are associated with the bits of plastic as they drift on the seas and wash up over Island reefs.

The California-based Algalita Foundation has helped conduct considerable research on drifting pollutants. University of the Pacific researchers Lorena Rios and Patrick Jones, along with Capt. Charles Moore, recently provided new insight in a paper, “Pacific organic pollutants carried by synthetic polymers in the ocean environment,” printed in the Marine Pollution Bulletin. Moore is the founder of Algalita and skipper of its research ship, Alguita.

Their research found that some plastics in the marine environment seem to absorb chemical pollutants from the environment. The research does not go so far as to show that these pollutants then get into the tissues of animals that eat the plastic—that is a study to be done later.

The problem of plastics in the ocean can't be overstated. The authors say that roughly 70 percent of marine litter is plastic. Previous studies show that plastic significantly outweighs plankton in much of the eastern Pacific.

A plastic toy, bottle or piece of fishing gear breaks in ultraviolet radiation from the sun into smaller and smaller pieces, but effectively never disappears from the environment, the authors write.

“They are not biodegradable in any practical human scale of time,” they write.

What hasn't been well studied is the relationship between these drifting and beach plastic chunks and organic pollutants. The ones studied include organo-chloride pesticides like DDT, industrial chemicals called PCBs or polychlorinated biphenyls, and polycyclic aromatic hydrocarbons (PAHs), which can be created by incomplete burning of fossil fuels, and some of which are used in chemical manufacturing.

This isn't the chemicals that are associated with plastic items when they are made, but rather chemicals that “stick” to the plastics as they move through the environment. That's a problem, because many forms of marine life, including fishes, seabirds, turtles and others, eat bits of plastic, either inadvertently as part of their regular feeding, or because they mistake bits of plastic for real food.

The researchers collected plastics, mainly polyethylene and polypropylene, from beaches in the Hawaiian archipelago, California, Mexico, from the puked-up stomach contents of seabirds, and from the surface of the North Pacific. They also collected samples from outdoor industrial sites like Mainland railyards where plastics were spilled during loading.

The plastic debris was then tested for the chemical pollutants. Not all plastic samples had detectable levels of the organic pollutants, but for instance, there was detectable DDT from Kualoa Beach on O'ahu, detectable PCBs on Kamilo Beach on the Big Island, and detectable PAH and PCB on samples from Tern Island on French Frigate Shoals in the Northwestern Hawaiian Islands.

The levels of PCBs at Tern Island was the highest found in any of the samples in the study. Tern Island has a documented PCB problem, associated with a landfill dating to the period when the island was used as a Coast Guard LORAN station.

The authors of this paper say the plastic debris seems to “absorb, accumulate and transport persistent organic pollutants.”

“These plastics are important point sources carrying (persistent organic pollutants),” the researchers write. And they're problems not only for the creature that eats the plastic, but then for the creatures that eat those creatures, and the ones that eat them.

© 2007 Jan W. TenBruggencate