Another Threat to Tuna: Ocean AcidificationMore acidic waters will cause massive organ failures in young yellowfin tuna, according to a new study
More acidic oceans could soon start dissolving tuna fish as they swim, long before they make it to consumers’ plates.
This worrying news comes from a study published last month in theJournal of Experimental Marine Biology and Ecology which found that increasing acidification in the Pacific Ocean—a function of climate change—will cause staggering levels of damage to multiple organs in yellowfin tuna (Thunnus albacares) larvae. The injuries, researchers found, will lessen the tunas’ ability to grow to full size and dramatically reduce their rates of survival.
Yellowfin tuna are already heavily overfished in some parts of the world, so this presents one more challenge to their survival.
For this study, researchers from the University of California at Santa Barbara, the Inter-American Tropical Tuna Commission and other organizations collected yellowfin larvae from a commercial aquaculture bloodstock which is normally exposed to pH levels between 8.27 and 7.74. That’s slightly more acidic then neutral water, which has a pH of 7. The larvae were taken then taken to a lab and exposed to waters with four different levels of carbon dioxide, which changed the pH. The first tank, considered the control, had a pH of 8.1. The second had a pH of 7.6, which matches global warming projections for the year 2100, while the third had a pH of 7.3, matching projections for the year 2300. A fourth pH level of 6.9 was considered the “lowest projection for the Pacific Ocean.”
All of that acid added up. The researchers found that it caused damage to the liver, kidney, pancreas, muscle tissue and eyes of the yellowfin larvae—all within a week of exposure. Their growth rates also suffered, ranging from 20 to 41 percent
What does all of that mean? Well, based on the damage to the eyes alone, the researchers concluded that the larvae would have had a mortality rate of between 50 and 100 percent. Even if they survived past those odds, the damage to their kidneys and other organs would have caused all kinds of health conditions later in life, putting them even further at risk.
As the researchers write, anything that causes high mortality rates for yellowfin or other fish in their earliest life stages “will have carry-over effects for marine fish stocks.” They argue that the uncertain future coming as a result of changing water temperatures, dissolved oxygen levels and pH “must be incorporated into future experiments in order to improve the relevance of predictions about the future of fish stocks and their sustainable management.”
In other words: star planning now if you want to keep enjoying tuna in the future.
Source : Scientific American
Link to Source
How we are all contributing to the destruction of coral reefs: Sunscreen
The sunscreen that snorkelers, beachgoers and children romping in the waves lather on for protection is killing coral and reefs around the globe. And a new study finds that a single drop in a small area is all it takes for the chemicals in the lotion to mount an attack.
The study, released Tuesday, was conducted in the U.S. Virgin Islands and Hawaii several years after a chance encounter between a group of researchers on one of the Caribbean beaches, Trunk Bay, and a vendor waiting for the day’s invasion of tourists. Just wait to see what they’d leave behind, he told the scientists – “a long oil slick.” His comment sparked the idea for the research.
Not only did the study determine that a tiny amount of sunscreen is all it takes to begin damaging the delicate corals — the equivalent of a drop of water in a half-dozen Olympic-sized swimming pools — it documented three different ways that the ingredient oxybenzone breaks the coral down, robbing it of life-giving nutrients and turning it ghostly white.
Yet beach crowds aren’t the only people who add to the demise of the coral reefs found just off shore. Athletes who slather sunscreen on before a run, mothers who coat their children before outdoor play and people trying to catch some rays in the park all come home and wash it off.
Cities such as Ocean City, Md., and Fort Lauderdale, Fla., have built sewer outfalls that jettison tainted wastewater away from public beaches, sending personal care products with a cocktail of chemicals into the ocean. On top of that, sewer overflows during heavy rains spew millions of tons of waste mixed with stormwater into rivers and streams. Like sunscreen lotions, products like birth-control pills contain chemicals that are endocrine disruptors and alter the way organisms grow. Those are among the main suspects in an investigation into why male fish such as bass are developing female organs.
Research for the new study was conducted only on the two islands. But across the world each year, up to 14,000 tons of sunscreen lotions are discharged into coral reef, and much of it “contains between 1 and 10 percent oxybenzone,” the authors said. They estimate that places at least 10 percent of reefs at risk of high exposure, judging from how reefs are located in popular tourism areas.
“The most direct evidence we have is from beaches with a large amount of people in the water,” said John Fauth, an associate professor of biology at the University of Central Florida in Orlando. “But another way is through the wastewater streams. People come inside and step into the shower. People forget it goes somewhere.”
The study was published Tuesday in the journal Archives of Environmental Contamination and Toxicology. Fauth co-authored the study with Craig Downs of the nonprofit Haereticus Environmental Laboratory in Clifford, Va., and Esti Kramarsky-Winter, a researcher in the Department of Zoology at Tel Aviv University in Israel.
Their findings follow a National Oceanic and Atmospheric Administration study two weeks ago that said the world is in the midst of a third global coral bleaching event. It warned that pollution is undermining the health of coral, rendering it unable to resist bleaching or recover from the effects.
“The use of oxybenzone-containing products needs to be seriously deliberated in islands and areas where coral reef conservation is a critical issue,” Downs said. “We have lost at least 80 percent of the coral reefs in the Caribbean. Any small effort to reduce oxybenzone pollution could mean that a coral reef survives a long, hot summer, or that a degraded area recovers.”
Coral reefs are more than just exotic displays of color on the sea bed. The National Marine Fisheries Service, a division of the NOAA, placed their value for U.S. fisheries at $100 million. They spawn the fish humans eat and protect miles of coast from storm surge.
“Local economies also receive billions of dollars from visitors to reefs through diving tours, recreational fishing trips, hotels, restaurants, and other businesses based near reef ecosystems,” NOAA said on its Web site. “Globally, coral reefs provide a net benefit of $9.6 billion each year from tourism and recreation revenues, and $5.7 billion per year from fisheries.”
Oxybenzone is mixed in more than 3,500 sunscreen products worldwide, including popular brands such as Coppertone, Baby Blanket Faces, L’Oreal Paris, Hawaiian Tropic and Banana Boat. Adverse effects on coral started on with concentrations as low as 62 parts per trillion. There are alternative sunscreens with no oxybenzone, including a product called Badger Natural Sunscreen and dozens of others on a list provided by the non-profit Environmental Working Group.
Measurements of oxybenzone in seawater within coral reefs in Hawaii and the U.S. Virgin Islands found concentrations ranging from 800 parts per trillion to 1.4 parts per million,” according to the authors. That’s 12 times the concentrations needed to harm coral.
“This study raises our awareness of a seldom-realized threat to the health of our reef life … chemicals in the sunscreen products visitors and residents wear are toxic to young corals,” said Pat Lindquist, executive director of the Napili Bay and Beach Foundation in Maui. “This knowledge is critical to us as we consider actions to mitigate threats or improve on current practices.”
Source : The Washington Post
Link to Source
Coral reefs die as El Niño hots up
Record sea temperatures combined with a strong El Niño are causing widespread coral bleaching, which is threatening to kill over 12,000 square kilometres of reefs.
The US National Oceanic and Atmospheric Administration (NOAA) has declared a global bleaching event, making this only the third such crisis in recorded history.
NOAA’s declaration has implications for the livelihoods of 500 million people worldwide and income worth $30 billion, because reefs support 25% of all marine species and are a nursery ground for many species of fish.
The bleaching is directly connected to climate change: it is the warmer water that causes the problem. The first global bleaching event was in 1998 and the second in 2010, both in years marked by El Niños, the periodic climate phenomenon in the Pacific.
Each time the potential for damage has been greater because the sea has been warmer before the start of the El Niño. This August the ocean was the warmest on record – and this time NOAA’s estimate is that 38% of the world’s reefs may be affected.
Coral bleaching this year began in the Florida Keys and South Florida in August. Record bleaching is now taking place in Hawaii; it is spreading to the Caribbean and may last until the New Year.
As the exceptionally warm water spreads across the Pacific the bleaching event is expected to hit the Great Barrier Reef in Australia in early 2016, causing more damage, some of it permanent.
Mark Eakin, NOAA’s Coral Reef Watch coordinator, said: “The coral bleaching and disease brought on by climate change, and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world.
“As a result, we are losing huge areas of coral across the US, as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016.”
Corals live in symbiosis with algae, and the two creatures depend on each other for survival. The apparent bleaching happens because as sea temperatures rise above coral comfort levels, the increasingly stressed corals and the colourful algae part company.
As a result, the corals whiten, lose their source of nutrients and – if the bleaching goes on for too long – will die.
Minor bleaching can be repaired and reefs recover, but at high temperatures and on this scale large areas can die. Apart from the loss of the corals, damage to the tourist industry and fishing, it also increases flood risk, because healthy reefs act as a storm barrier for many islands and low-lying coasts.
Graphic illustrations of bleaching can be seen on a website set up to alert people to the dangers and record the event.
There is particular concern on Hawaii at the moment. It suffered bad bleaching in 2014, which is currently getting worse.
Eakin said the bleaching was a crisis. “Hawaii is getting hit with the worst coral bleaching they have ever seen, right now. It’s severe. It’s extensive. And it’s on all the islands.
“In one part of northwestern Hawaii the reef just completely bleached and all of the coral is dead and covered with scuzzy algae.”
The bleaching has also struck Cuba, Haiti and the Dominican Republic and is about to hit Puerto Rico and the Virgin Islands, he said. Oceans worldwide are by far the warmest on record – August 2015 was two-fifths of a degree warmer than August 1998. Eakin said: “Next year may be as bad as this year or even worse.”
Gregor Hodgson, who heads the group Reef Check Australia, is concerned about the forecast that the warm blob of water caused by El Niño will hit the country’s Great Barrier Reef early next year.
The reef is the planet’s biggest, a world heritage site and a magnet for tourists. The computer model forecasts “this horrendous, dramatic” impact on the reef, Hodgson said. “It’s truly terrifying.”
Source – Climate News Network
Link to Source
Ocean Life Faces Mass Extinction, Broad Study Says
A team of scientists, in a groundbreaking analysis of data from hundreds of sources, has concluded that humans are on the verge of causing unprecedented damage to the oceans and the animals living in them.
“We may be sitting on a precipice of a major extinction event,” said Douglas J. McCauley, an ecologist at the University of California, Santa Barbara, and an author of the new research, which was published on Thursday in the journal Science.
But there is still time to avert catastrophe, Dr. McCauley and his colleagues also found. Compared with the continents, the oceans are mostly intact, still wild enough to bounce back to ecological health.
“We’re lucky in many ways,” said Malin L. Pinsky, a marine biologist at Rutgers University and another author of the new report. “The impacts are accelerating, but they’re not so bad we can’t reverse them.”
Scientific assessments of the oceans’ health are dogged by uncertainty: It’s much harder for researchers to judge the well-being of a species living underwater, over thousands of miles, than to track the health of a species on land. And changes that scientists observe in particular ocean ecosystems may not reflect trends across the planet.
Dr. Pinsky, Dr. McCauley and their colleagues sought a clearer picture of the oceans’ health by pulling together data from an enormous range of sources, from discoveries in the fossil record to statistics on modern container shipping, fish catches and seabed mining. While many of the findings already existed, they had never been juxtaposed in such a way.
A number of experts said the result was a remarkable synthesis, along with a nuanced and encouraging prognosis.
“I see this as a call for action to close the gap between conservation on land and in the sea,” said Loren McClenachan of Colby College, who was not involved in the study.
There are clear signs already that humans are harming the oceans to a remarkable degree, the scientists found. Some ocean species are certainly overharvested, but even greater damage results from large-scale habitat loss, which is likely to accelerate as technology advances the human footprint, the scientists reported.
Coral reefs, for example, have declined by 40 percent worldwide, partly as a result of climate-change-driven warming.
Some fish are migrating to cooler waters already. Black sea bass, once most common off the coast of Virginia, have moved up to New Jersey. Less fortunate species may not be able to find new ranges. At the same time, carbon emissions are altering the chemistry of seawater, making it more acidic.
“If you cranked up the aquarium heater and dumped some acid in the water, your fish would not be very happy,” Dr. Pinsky said. “In effect, that’s what we’re doing to the oceans.”
Fragile ecosystems like mangroves are being replaced by fish farms, which are projected to provide most of the fish we consume within 20 years. Bottom trawlers scraping large nets across the sea floor have already affected 20 million square miles of ocean, turning parts of the continental shelf to rubble. Whales may no longer be widely hunted, the analysis noted, but they are now colliding more often as the number of container ships rises.
Mining operations, too, are poised to transform the ocean. Contracts for seabed mining now cover 460,000 square miles underwater, the researchers found, up from zero in 2000. Seabed mining has the potential to tear up unique ecosystems and introduce pollution into the deep sea.
The oceans are so vast that their ecosystems may seem impervious to change. But Dr. McClenachan warned that the fossil record shows that global disasters have wrecked the seas before. “Marine species are not immune to extinction on a large scale,” she said.
Until now, the seas largely have been spared the carnage visited on terrestrial species, the new analysis also found.
The fossil record indicates that a number of large animal species became extinct as humans arrived on continents and islands. For example, the moa, a giant bird that once lived on New Zealand, was wiped out by arriving Polynesians in the 1300s, probably within a century.
But it was only after 1800, with the Industrial Revolution, that extinctions on land really accelerated.
Humans began to alter the habitat that wildlife depended on, wiping out forests for timber, plowing under prairie for farmland, and laying down roads and railroads across continents.
Species began going extinct at a much faster pace. Over the past five centuries, researchers have recorded 514 animal extinctions on land. But the authors of the new study found that documented extinctions are far rarer in the ocean.
Before 1500, a few species of seabirds are known to have vanished. Since then, scientists have documented only 15 ocean extinctions, including animals such as the Caribbean monk seal and the Steller’s sea cow.
While these figures are likely underestimates, Dr. McCauley said that the difference was nonetheless revealing.
“Fundamentally, we’re a terrestrial predator,” he said. “It’s hard for an ape to drive something in the ocean extinct.”
Many marine species that have become extinct or are endangered depend on land — seabirds that nest on cliffs, for example, or sea turtles that lay eggs on beaches.
Still, there is time for humans to halt the damage, Dr. McCauley said, with effective programs limiting the exploitation of the oceans. The tiger may not be salvageable in the wild — but the tiger shark may well be, he said.
“There are a lot of tools we can use,” he said. “We better pick them up and use them seriously.”
Dr. McCauley and his colleagues argue that limiting the industrialization of the oceans to some regions could allow threatened species to recover in other ones. “I fervently believe that our best partner in saving the ocean is the ocean itself,” said Stephen R. Palumbi of Stanford University, an author of the new study.
The scientists also argued that these reserves had to be designed with climate change in mind, so that species escaping high temperatures or low pH would be able to find refuge.
“It’s creating a hopscotch pattern up and down the coasts to help these species adapt,” Dr. Pinsky said.
Ultimately, Dr. Palumbi warned, slowing extinctions in the oceans will mean cutting back on carbon emissions, not just adapting to them.
“If by the end of the century we’re not off the business-as-usual curve we are now, I honestly feel there’s not much hope for normal ecosystems in the ocean,” he said. “But in the meantime, we do have a chance to do what we can. We have a couple decades more than we thought we had, so let’s please not waste it.”
Source : The Times
Link to Source
Ten years after ESA listing, killer whale numbers falling
Puget Sound’s already small killer-whale population has declined in the decade since it was protected under the Endangered Species Act. Some experts view the death this month of a pregnant female orca as an alarm bell for the region’s southern residents.
He’s trailed them and photographed them, mapped their family trees and counted their offspring, coming to identify individuals by their markings, sometimes even ascribing personalities based on behavior.
For much of the past 40 years, the dean of San Juan Island orca research has vacillated between hope and frustration about the future of Puget Sound’s southern resident killer whales.
But the death this month of J32, an 18-year-old orca known as Rhapsody — who was pregnant with a nearly full-term female calf — is pushing Ken Balcomb closer to despair.
“The death of this particular whale for me shows that we’re at a point in history where we need to wake up to what we have to consider: ‘Do we want whales or not?’ ” said Balcomb, with the Center for Whale Research.
With 2015 marking the 10th anniversary of the government’s decision to protect these orcas under the Endangered Species Act (ESA), the numbers certainly don’t look good.
The population of J, K and L pods has dropped from a high of 99 in 1995 to 77 this month — the lowest since 1985. No whale has successfully given birth in more than two years — a first in the decades since whales have been monitored. And the small number of female whales able and likely to give birth reduces the potential for a speedy rebound.
In fact scientists had hoped young J32, who was just coming into adulthood, would help turn that pattern around for decades to come.
“We’ve not only lost her, but we’ve lost all of her future reproductive potential, which will potentially have an impact on the population,” said Brad Hanson, killer-whale expert with the National Oceanic and Atmospheric Administration’s (NOAA) Northwest Fisheries Science Center. “That’s disconcerting.”
Even the apparent cause of J32’s demise — an infection spread by the death of her unborn calf — leads Balcomb to suspect the worst. He thinks the whales’ chief source of food, chinook salmon, is in such short supply that J32 relied on its own blubber, releasing stored contaminants that harmed her immune and reproductive systems.
But officials overseeing whale recovery say it’s too soon to say the situation is, in fact, dire. The root cause of the infection’s spread is not yet clear and may prove complex. It’s not known if the lack of successful new births is a trend or anomaly. And whale numbers have been lower than this before and bounced back, suggesting to some that there is room for optimism.
After all, said Will Stelle, West Coast administrator for NOAA Fisheries, Snake River sockeye runs were so depleted in 1992 that only one fish — known as Lonesome Larry — returned to spawn in Idaho’s Redfish Lake. This year, after decades of work by scientists, 1,600 fish returned, nearly 500 of which were naturally spawned.
“That’s not to say the issues around Snake River sockeye are the same — they’re not,” Stelle said. “But if you look in the rearview mirror, you’ll see that in fact over the last decade we’ve made substantial progress in building the basic foundation for a long-term conservation strategy for southern residents. We’re by no means there. But a decade ago we were in the dark ages.
“This is not the time to light our hair on fire, or to run about saying ‘The sky is falling, the sky is falling,’ ” he said. “What is really important here is to take the long view.”
But even Stelle agreed a central question remains: How much time do orcas have?
J32 was born into a family where adult females tended to die early. She was the first and, presumably, only calf of a 15-year-old whale that died two years later. The matriarch of the family died a year after that at 37 — early for a species with a life span similar to humans.
But it’s a sad irony that this salmon-eating machine wound up dead in front of a chinook-fishing charter business in British Columbia.
Long before her carcass was towed ashore on the east side of Vancouver Island near Comox, B.C., early this month, scientists had begun to wrestle with the role salmon declines may be playing in whale survival.
“The reality is, the basic problem is food,” Balcomb said.
In the 1960s and 1970s, an orca population that a century earlier may have numbered anywhere from 140 to 200 was decimated by the aquarium trade. Entrepreneurs drove orcas into net pens in coves and sold them to marine parks around the globe until their numbers had plummeted to just 71 in 1974.
Only in the last 10 years have researchers truly documented their troubles.
“Since then we’ve improved our understanding of the individuals themselves, their population dynamics, their geographic distribution and diet and pollutant loading and contaminants and the effects of all that on productivity,” Stelle said.
But two of the whales’ three biggest problems — the buildup of pollutants such as DDT and polychlorinated biphenyls in their blubber, and disturbance by marine traffic — appear to be worsened by a third, a reduction in available prey.
These whales can eat sockeye and halibut, but overwhelmingly prefer fatty chinook from Puget Sound and Canada’s Fraser River, distinguishing them from other fish by using sonar to sense differences in the animals’ swim bladders. And Puget Sound chinook numbers have dropped to about 10 percent of their historic high. They, too, are listed for protection under the ESA.
When killer whales are hungry, research suggests they may metabolize poisons built up in their fat over years, and expend energy they can’t afford if they have to avoid disturbance from boats and other traffic.
Yet scientists continue to disagree on how much of a role that has ever played in any deaths. Few whales wash up dead for them to study. Among those that have, only one — Rhapsody’s uncle, J18 — offered clues that led some, but not all, to believe hunger was a factor in his death.
Government scientists certainly agree that a diminished food supply is a major issue. But they’re still running tests on J32’s organs, skin and fatty tissue to help narrow down her health issues more precisely.
“If southern residents are on a lower nutritional plane, then the effects of contaminants may be allowed to cause some sort of problem in a random way that disease events would be able to take over,” Hanson said. “But a lot of times what we’re seeing is these skinny animals and a lot of people say ‘these whales are starving to death.’ But it’s not that simple.”
For example, whales hunt in groups and sometimes share prey, and may give away food to others that they themselves could use.
Regardless of whether food availability helped trigger her death, government researchers share some of Balcomb’s concerns about the state of the population.
“It’s not so much that there are fewer reproductive-age females now than there used to be,” said NOAA whale scientist Mike Ford, “but rather that they may not be giving birth as often as expected.”
For Balcomb, the loss of J32 suggests it’s time to consider drastic measures, such as a ban or steep curtailment in chinook fishing, even though fishing is likely the least of the threats chinook face.
“It’s a wake-up call — we know what the problem is, whether it’s dams or fishing or habitat destruction,” he said. “It’s just what happens when millions of people move into the watershed. (But) stopping fishing, at least for a while, is something we can do immediately.”
Stelle, whose agency helps oversee chinook-harvest levels, said fishing has been curtailed already by about 30 percent in agreements with the Canadians, but he couldn’t conceive of a day when he’d seriously consider an outright ban, which would violate tribal-treaty rights. Still, he doesn’t rule out even more drastic cuts.
Stelle, like most experts, maintains that one of the hardest problems to address for orcas is controlling stormwater so even more contaminants aren’t flushed into the Sound, where they can work their way up the killer whale food chain. That is likely an expensive fix.
The other is reducing development in areas harmful to chinook survival — estuaries, floodplains, areas that alter drainage into river beds. But that problem is made ever more complex by the fact that dozens of government entities oversee all that decision-making.
“The particular challenges I think that are daunting can best be illustrated by driving south on I-5 and looking around,” he said. “That built-out landscape fundamentally poses the most significant challenge for us. It is: How do we reconcile the continued human-population growth projected for the basin with trying to rebuild the productivity of the most important habitats for orcas and their prey.”
Martha Kongsgaard, who leads the Puget Sound Partnership, a government agency charged with cleaning up the Sound, agreed J32’s death puts into relief just how much is at stake if the region doesn’t pick up the pace in tackling these problems.
“You don’t want to raise the alarm every time a whale dies, but I think we are really on the brink of possibly losing them,” she said. “And we ignore the orcas’ incredible totemic and symbolic power at our peril. They’re telling us it’s an emergency right now.
Source : Seattle Times
Link to Full Article
The world’s scallops and oysters are mysteriously dying out
The pristine, sheltered sounds off Vancouver Island, British Columbia, offer the cleanliness and protection ideal for farming oysters, clam, scallops, and other shellfish. Since the 1970s, the industry has grown so rapidly that the area once supplied nearly two-fifths of Canada’s farmed shellfish and is the coastal community’s economic backbone.
But something is killing them off. In the last two years, nine-tenths of baby oysters have died in Desolation Sound farms (the normal mortality rate is about 50%). Scallop farmers off Vancouver Island have reportedmass die-offs of their hatchlings since 2010. British Columbia’s share of Canada’s aquaculture industry is in a tailspin.
Further down the coast, the US’s $270-million Pacific Northwestshellfish industry is teetering (paywall) following the mysterious 2008 oyster die-off.
Scientists aren’t sure what the culprit is. Environmental stressors are rising, creating a complex interplay of factors. For instance, BC’s typically chilly coastal waters are warming—and that’s shifting the timing of zooplankton blooms, which in turn feed the shellfish. Scientists say seemingly slight ecosystem changes have likely compound the destruction of a deadly oyster herpes virus that has been wiping out oysters in France and Australia.
Though not all scientists agree, many suspect that one lethal factor is the the area’s falling pH levels, which have slipped from an average of 8.1 between 1954 and 1974 to 7.2 by 2001. (A pH of below 7 is considered acidic, with 6 about the acidity of urine and 5 that of black coffee.)
In other words, the sea is bathing shellfish in water that increasingly resembles acid, which deprives the water of the carbonate ions that baby mollusks need to grow tough shells. That likely leaves them more vulnerable to parasites and disease, says Curtis Suttle, a marine biologist and virologist at the University of British Columbia. A recent study on sea butterflies—tiny snail-like creatures that are important in the food chain—found them struggling to survive as a result of theirshells being eaten away.
At the root of these changes are rising CO2 levels. Broadly, the ocean absorbs nearly a third of the carbon dioxide released into the atmosphere each year, say scientists. As CO2 levels rise, so do the amounts sucked up by the ocean, changing the seawater’s chemistry in the process. By 2,100, scientists predict the ocean will be 170% more acidic than it was before the Industrial Revolution. This will put commercial fishing stocks all over the planet at risk.
But the Pacific Northwest is unusually vulnerable. Winds that gust south in the summer whip deeper water to the surface. Since CO2 tends to be trapped in colder depths for many decades, these upwellings are naturally more acidic.
The oysters grown off the Pacific Northwest aren’t native to the area; the lack of similar upwellings in their native Japanese waters leaves them poorly adapted even to these natural extremes in upwelling acidity. The additional acidity that comes from manmade CO2 now exceeds their ability to tolerate it (see Seattle Times reporter Craig Welch’s wrap-up of the science for more).
Many Pacific Northwest shellfish farmers have switched to raise baby shellfish in buffered hatcheries until their shells are strong enough to withstand the ocean. It’s probably not a long-term fix, though. The upwelling acidity likely comes from CO2 absorbed back in the 1960s, when atmospheric CO2 was less than 80% of today’s levels. Now, there’s a heck of a lot more where that came from.
Source : Quartz
Link to Source + Graphs
The Ocean Contains Over Five Trillion Pieces of Plastic Weighing More than 250,000 Tons
These frightening figures represent the most robust estimate of marine plastic pollution calculated to date
Plastic is the most pervasive pollutant in the ocean today. But researchers have struggled to estimate just how much of the 6 billion tons of plastic that has been manufactured since the mid-20th century ultimately winds up in the ocean.
Now a carefully vetted estimate of our oceans’ plastic burden shows that the answer is not pretty. Based on the calculations, at least 5.25 trillion pieces of plastic—weighing nearly 269,000 tons—are currently bobbing around in the ocean. A team of researchers from six countries reported the finding today in PLOS ONE.
Revealing this disturbing figure required the team to conduct 24 garbage-collecting expeditions between 2007 and 2013. Those trips to sea included visits to all five sub-tropical gyres—large systems of constantly rotating currents infamous for their roles in creating garbage patches—plus the Mediterranean Sea, the Bay of Bengal and Australia. At all of the sites, teams collected water samples for estimating the amount of microplastic, pieces of plastic smaller than 4.75 millimeters. They also tallied up larger pieces using standardized visual surveys. These data represent the most comprehensive tally yet done for ocean plastic pollution.
With their field data in hand, the researchers created a computer model to estimate the total quantity and weight of the world’s marine plastic. The model assumed that plastic entered the ocean via rivers, coastlines and ships, and it took factors like wind-driven vertical mixing, currents and the amount of plastic that winds up on the ocean floor into account. The team also corroborated their estimates with field tests.
In addition to the weight estimate, the team made an important and frightening observation: Large pieces of plastic tended to be most concentrated near coasts, but the smallest particles they measured—from the size of a grain of sand to a grain of rice—accounted for about 90 percent of the total garbage count. It seems that plastic gets chewed into microplastic once it hits an ocean gyre, where it is broken down by a combination of waves, ultraviolet radiation from the sun, oxidation and nibbling fish. Given these findings, ocean garbage patches may be more aptly named garbage blenders.
To make matters worse, the newly created microplastic doesn't stay put, but instead gets spewed from the gyre into the greater ocean. Every water sample the researchers took, no matter how remote, was laced with some amount of microplastic. The team was shocked to discover multitudes of microplastic near the subpolar gyres, for example, corroborating recent findings that high amounts of the humanmade material can also be found in sea ice.
The extreme reach of plastic pollution is a problem, because those barely noticeable pieces can bind to pollutants and, when ingested by marine animals, can act as mini toxic bombs, gut-clogging confetti or both. As Marcus Eriksen, director of research for the 5 Gyres Institute and lead author of the study, told PLOS: “The endgame for micro-plastic is interactions with entire ocean ecosystems.”
Source : Smithsonian Mag.
Link to Source