The Great London:
Oceans

Killer whales in European waters face extinction due to outlawed but long-lived pollutants that also threaten several species of dolphins, according a study published in the journal >Scientific Reports.

Toxic chemicals known by the acronym PCBs are poisoning these marine mammals, and in some cases severely impeding their ability to reproduce, researchers reported.

Becoming more concentrated as they move up the food chain, PCBs settle into the fatty tissue of top ocean predators.

The deadly compounds—used in manufacturing and construction and banned across the European Union in 1987—can also be passed on to orca and dolphin calves suckling their mothers' milk.

"Few coastal orca populations remain in western European waters," said lead author Paul Jepson of the Zoological Society of London, noting that those in the Mediterranean and North Sea have already disappeared.

"The ones that do persist are very small and suffering low or zero rates of reproduction."

A community of 36 orcas, or killer whales, off the coast of Portugal—observed by scientists for decades—has not produced any offspring in more than ten years, the study reported.

An even smaller grouping near Scotland "will go extinct," Jepson told journalists by phone.

The death of a female known as Lulu, whose carcass was discovered on the Scottish island of Tiree last week, reduced this pod from nine to eight.

As well as direct observation, biopsies of individuals in the wild have also shown that these orca populations are not reproducing.

When female killer whales give birth, they transfer about 90 percent of the PCBs accumulated in their bodies—sometimes over decades—to their calves, purging themselves but poisoning their offspring.

Recent biopsies, however, revealed that all the females have the same level of PCB toxins in their system as males, evidence that they had not produced calves in the preceding years.

The toxic effect of PCBs on marine mammals was known, but this is the first overview—based on tissue samples from more than 1,000 stranded and biopsied whales, dolphins and orcas—of the extent of the damage.

Climbing the food chain

PCBs were widely used in manufacturing electrical equipment, paints and flame retardants. Designed to withstand weathering, they were also added to sealants used in buildings.

Europe produced some 300,000 tonnes of the compound from 1954 to 1984, and 90 percent of it has yet to be destroyed or safely stored away.

PCBs—which do not dissolve in water—reach the ocean via several routes.

"It is leaching from landfills into rivers and estuaries, and eventually into the marine environment," Jepson explained.

Sediment dredging to a depth of ten metres (30 feet) along shipping lanes in industrial ports brings the deadly chemicals to the surface.

From there, they gradually climb the food chain, becoming more toxic along the way: from bottom-feeding mollusks to crabs to small fish to the bigger fish eaten by orcas, dolphins and porpoises.

Further north, a healthier population of several thousand orcas living in waters near Iceland and northern Norway provide additional evidence that PCBs are, in fact, causing the decline of their cousins to the south.

Whereas the southern killer whales eat large fish and mammals, such as seals, the Arctic orcas subsist almost exclusively on herring.

Because herring eat plankton, they are outside the food chain along which PCBs climb, explaining why the northern orcas have ten times less PCB in their fatty tissue.

Disposing of land-based PCBs—made to resist heat, chemical attack and degradation—is difficult, Jepson said.

"They were designed to last a very long time, so it is incredibly hard to destroy them."

Author: Marlowe Hood | Source: AFP [Janaury 14, 2016]

Scientists have discovered that stunted growth can be a genetic response to ocean acidification, enabling some sea creatures to survive high carbon dioxide levels, both in the future and during past mass extinctions.

Using natural CO2 seeps as test sites, the international team of marine scientists and palaeontologists have studied the way in which sea snails cope in more acidic conditions ‒ simulating the change in seawater chemistry that will occur in future as more atmospheric CO2 is absorbed by the ocean.

The researchers say their findings, published in Nature Climate Change, provide an explanation as to why marine species that survived previous mass extinction events were much smaller – a phenomenon known as the ‘Lilliput effect’.

The research was funded by the EU MedSeA project and the UK Ocean Acidification Research Programme, and involved researchers from 10 institutions including Plymouth University, the University of Southampton, the Natural History Museum, London, and colleagues in Italy, Monaco, Norway and New Caledonia.

Its results provide a stark warning about the impact that continuing ocean acidification could have on marine ecosystems unless we drastically slow the rate of carbon dioxide emissions.

Dr Vittorio Garilli, at Paleosofia-APEMA, Palermo, said: “Two species of snails growing at shallow water CO2 seeps were smaller than those found in normal pH conditions, and adapted their metabolic rates to cope with the acidified seawater. These physiological changes allowed the animals to maintain calcification and to partially repair shell dissolution.”

Professor Jason Hall-Spencer, of the School of Marine Science and Engineering at Plymouth University, said: “Organisms that have been exposed to elevated CO2 levels over multiple generations provide valuable insights both into changes we can expect in marine ecosystems as CO2 emissions continue to rise unchecked, and into past mass extinctions."

“Not only do they demonstrate a similar magnitude and direction of body size change as fossil organisms, but they also reveal the physiological advantages of dwarfing,” added Professor Marco Milazzo at Palermo University.

Measurements showed that the shells from high CO2 seawater were about a third smaller than those in “normal” environments. Some of the snails were taken to the Marine Environmental Studies Laboratory at the International Atomic Energy Agency in Monaco, where their calcification rates were measured in aquaria.

Study co-leader Dr Riccardo Rodolfo-Metalpa, from the Institut de Recherche pour le Développement, said: “They developed a surprising ability to calcify and cope with shell dissolution at pH values which were thought too low for calcification to occur.”

The results – published in the paper Physiological advantages of dwarfing in surviving extinctions in high CO2 oceans – confirmed the theory that the snails had adapted to the conditions over many generations.

Professor Richard Twitchett, of the Department of Earth Sciences at the Natural History Museum, said: “The fossil record shows us that mass extinctions and dwarfing of marine shelled species are repeatedly associated with episodes of past global warming. It is likely that similar changes will increasingly affect modern marine ecosystems, especially as the current rate of ocean acidification and warming is so rapid."

Professor Hall-Spencer added: “It is critical that we understand the mechanisms by which certain species survive chronic exposure to elevated CO2 since emissions of this gas are already having adverse effects on marine foodwebs and putting food security at risk.”

Author: Andrew Merrington | Source: University of Plymouth [April 21, 2015]

With scientists forecasting sea levels to rise by anywhere from several inches to several feet by 2100, historic structures and coastal heritage sites around the world are under threat. Some sites and artifacts could become submerged.

Scientists, historic preservationists, architects and public officials are meeting this week in Newport, Rhode Island—one of the threatened areas—to discuss the problem, how to adapt to rising seas and preserve historic structures.

"Any coastal town that has significant historic properties is going to be facing the challenge of protecting those properties from increased water and storm activity," said Margot Nishimura, of the Newport Restoration Foundation, the nonprofit group hosting the conference.

Federal authorities have encouraged people to elevate structures in low-lying areas, but that poses challenges in dense neighborhoods of centuries-old homes built around central brick chimneys, Nishimura said, especially ones where preservationists are trying to keep the character intact.

Many of the most threatened sites in North America lie along the East Coast between Cape Hatteras, North Carolina, and southern Maine, where the rate of sea level rise is among the fastest in the world, said Adam Markham, of the Union of Concerned Scientists, a speaker at the conference.

"We're actually not going to be able to save everything," he said.

A look at some of the historic areas and cultural sites that are under threat from rising sea levels:

Statue of Liberty and Ellis Island

Situated in New York Harbor, the Statue of Liberty and Ellis Island are some of New York's most important tourist attractions.

In 2012, Superstorm Sandy submerged most of the low-elevation Liberty and Ellis islands. After the storm, the Statue of Liberty, a gift from the people of France in 1886, was closed for eight months. Ellis Island, the entry point for about 12 million immigrants to the United States from 1892 to 1954, remained closed for nearly a year.

A report by the National Park Service looked at how several parks would be threatened by 1 meter, or around 3 feet, of sea level rise. It found $1.51 billion worth of assets at the Statue of Liberty National Monument were highly exposed to sea level rise.

Much of historic Boston is along the water and is at risk due to sea level rise, including Faneuil Hall, the market building known as the "Cradle of Liberty," and parts of the Freedom Trail, a walking trail that links historic sites around the city.

Boston has seen a growing number of flooding events in recent years, up from two annually in the 1970s to an average of 11 annually between 2009 and 2013, according to a 2014 report by the Union of Concerned Scientists. If sea levels rise by 5 inches, the group reported, the number of floods is projected to grow to 31 annually. If seas rise by 11 inches, the number of flooding events is projected to rise to 72 per year.

Newport

The Point neighborhood in the Rhode Island resort town has one of the highest concentrations of Colonial houses in the United States, and it sits 4 feet above mean sea level. Tidal flooding is already occurring in the neighborhood, and that is expected to increase as sea levels rise, Nishimura said. The smell of sea water already permeates the basement of some homes.

Annapolis

Maryland's capital, on Chesapeake Bay, boasts the nation's largest concentration of 18th-century brick buildings. The city briefly served as the nation's capital in the post-Revolutionary War period, and the Treaty of Paris, which formally ended the war, was ratified there. The city is also home to the U.S. Naval Academy.

The city already sees tidal flooding dozens of times a year, and scientists have predicted number could rise to hundreds annually in the next 30 years.

Jamestown

Established in 1607, it is the first permanent English colony in North America. It sits along the tidal James River in Virginia, and most of the settlement is less than 3 feet above sea level. A large part of the settlement has already eroded because of wave action, Markham said. Storms have also damaged the site, including Hurricane Isabel in 2003, which flooded nearly 1 million artifacts. A rising water table at the site also poses a threat to archaeological remains, Markham said.

He called the loss of archaeological artifacts "an urgent problem" along the U.S. coastline.

Hawaii

Reports by the National Park Service and others have found that rising sea level rises threaten archaeological sites at various historic places in Hawaii. Those include ancient fish ponds at Pu'ukohola Heiau National Historic Site and a "Great Wall" at a sacred site in Pu'uhonua o Honaunau National Historical Park. It is considered the best-preserved such wall in Hawaii.

International Sites

Dozens of UNESCO World Heritage Sites are under threat from sea level rise, according to a 2014 report by climate scientists Ben Marzeion, of the University of Innsbruck in Austria, and Anders Levermann, of the Potsdam Institute in Germany.

Among those are: the Tower of London; Robben Island in South Africa, where Nelson Mandela was imprisoned for 27 years; Venice, Italy, and its lagoon; Mont-Saint-Michel, home to an abbey built atop a rocky islet in France; the Kasbah of Algiers, Algeria; the historic district of Old Quebec, Canada; Old Havana in Cuba; and archaeological areas of Pompeii, Italy, and Carthage in Tunisia.

The authors wrote that their findings indicate that "fundamental decisions with regard to mankind's cultural heritage are required."

Author: Michelle R. Smith | Source: The Associated Press [April 11, 2016]

A new study says that more than 17,000 marine species worldwide remain largely unprotected, with the U.S. among the bottom in supporting formal marine protected areas (MPAs) that could safeguard marine biodiversity.

The study, which is the first comprehensive assessment of protected areas coverage on marine life, appears in the international journal Scientific Reports. Authors include scientists from University of Queensland, the Australian Research Council Centre of Excellence for Environmental Decisions (CEED), UC Santa Barbara, the National Center for Ecological Analysis and Synthesis, Imperial College London and the Wildlife Conservation Society.

The authors looked at the ranges of some 17,348 species of marine life, including whales, sharks rays and fish, and found that 97.4 percent have less than 10 percent of their range represented in marine protected areas. Nations with the largest number of "gap species" or species whose range lie entirely outside of protected areas include the U.S., Canada, and Brazil.

Despite these dismal results, the authors say the study underscores opportunities to achieve goals set by the Convention on Biological Diversity to protect 10 percent of marine biodiversity by 2020. For example, the majority of species that were considered very poorly represented (less than two percent of their range found in marine protected areas) are found in exclusive economic zones. This suggests an important role for particular nations to better protect biodiversity.

"The process of establishing MPAs is not trivial as they impact livelihoods. It is essential that new MPAs protect biodiversity whilst minimizing negative social and economic impacts. The results of this study offer strategic guidance on where MPAs could be placed to better protect marine biodiversity." said the study's lead author Dr Carissa Klein of the University of Queensland and CEED.

The authors say that it is imperative that new MPAs are systematically identified and take into account what has already been protected in other places, in addition to socioeconomic costs of implementation, feasibility of success, other aspects driving biodiversity.

"The increase in the number MPAs in recent years is encouraging, but most of this increase has come from a few very large MPAs," said Dr. Ben Halpern of UC Santa Barbara and NCEAS. "Those very large MPAs provide important value, but they can be misleading in thinking that biodiversity is being well protected because of them. Species all around the planet need protection, not just those in some locations. Our results point out where the protection gaps exist."

Said co-author Dr. James Watson of WCS and the University of Queensland: "As most marine biodiversity remains extremely poorly represented, the task of implementing an effective network of MPAs is urgent. Achieving this goal is imperative for not just for nature but for humanity, as millions of people depend on marine biodiversity for important and valuable services."

Source: Wildlife Conservation Society [December 03, 2015]

Scientists working in the mid-Atlantic and south-west Indian Ocean have found evidence of microfibers ingested by deep sea animals including hermit crabs, squat lobsters and sea cucumbers, revealing for the first time the environmental fallout of microplastic pollution.

The UK government recently announced that it is to ban plastic microbeads, commonly found in cosmetics and cleaning materials, by the end of 2017. This followed reports by the House of Commons Environmental Audit Committee about the environmental damage caused microbeads. The Committee found that a single shower can result in 100,000 plastic particles entering the ocean.

Researchers from the universities of Bristol and Oxford, working on the Royal Research Ship (RRS) James Cook at two sites, have now found evidence of microbeads inside creatures at depths of between 300m and 1800m. This is the first time microplastics -- which can enter the sea via the washing of clothes made from synthetic fabrics or from fishing line nets -- have been shown to have been ingested by animals at such depth.

Laura Robinson, Professor of Geochemistry in Bristol's School of Earth Sciences, said: "This result astonished me and is a real reminder that plastic pollution has truly reached the furthest ends of the Earth."

Microplastics are generally defined as particles under 5mm in length and include the microfibres analysed in this study and the microbeads used in cosmetics that will be the subject of the forthcoming Government ban.

Among the plastics found inside deep-sea animals in this research were polyester, nylon and acrylic. Microplastics are roughly the same size as 'marine snow' -- the shower of organic material that falls from upper waters to the deep ocean and which many deep-sea creatures feed on.

Dr Michelle Taylor of Oxford University's Department of Zoology, and lead author of the study, said: "The main purpose of this research expedition was to collect microplastics from sediments in the deep ocean -- and we found lots of them. Given that animals interact with this sediment, such as living on it or eating it, we decided to look inside them to see if there was any evidence of ingestion. What's particularly alarming is that these microplastics weren't found in coastal areas but in the deep ocean, thousands of miles away from land-based sources of pollution."

The animals were collected using a remotely operated underwater vehicle. The study, funded by the European Research Council (ERC) and the Natural Environment Research Council (NERC), was a collaboration between The University of Oxford, the University of Bristol, the Natural History Museum in London, and Staffordshire University's Department of Forensic and Crime Science, which made sure the results were robust and the study was free from potential contamination.

Dr Claire Gwinnett, Associate Professor in Forensic and Crime Science at Staffordshire University, said: "Existing forensic approaches for the examination of fibres are tried and tested for their robustness and must stand up to the scrutiny of the courts of law. These techniques were employed in this research in order to effectively reduce and monitor contamination and therefore provide confidence in the fact that the microplastics found were ingested, and not from the laboratory or other external contaminant.

"Using forensic laboratory techniques, we have identified that microplastics are present in ingested material from deep sea creatures. Forensic science is still a fairly new science, but we are delighted that our work and techniques are starting to inform other sciences and important environmental research such as this."

The results are published in the journal >Scientific Reports.

Source: University of Bristol [September 30, 2016]

Trekking across the high Canadian Arctic almost 20 years ago, Howie Scher had an unexpected encounter that helped fix the course of his career.

An undergraduate on a research expedition over summer break, Scher was part of a scientific group traveling deep into the Arctic Circle to collect basalt cores for paleomagnetic analysis. But as focused as the team was on finding rocks with magnetic minerals that can help establish where on Earth they had formed, it was stony deposits that had once been very much alive that really caught the team's collective eye.

"We stumbled across a fossil bone bed there," Scher says. "We were pulling out vertebrate fossils--crocodilians, turtles, bony fish--and when we got home we showed them to a paleontologist who told us it was a warm water assemblage. That was a great experience as a freshman in college, and it got me very interested in climate--just seeing how it had been so different in the past than what my experience was near the North Pole, trudging through the snow."

Now an associate professor at the University of South Carolina, Scher has made a career of climate science. He is part of an international team that recently published a report pinpointing the genesis of one of the cornerstones of the Earth's current climate system, the Antarctic Circumpolar Current.

A constant eastward flow of ocean water in the Southern Ocean encircling Antarctica, the Antarctic Circumpolar Current is akin to the Gulf Stream, the current that moves water through the Atlantic Ocean from the tip of Florida, along the east coast of North America, and, by extension into the North Atlantic Current, to the shores of western and northern Europe. The Gulf Stream's transport of warm southern waters northward is why many European countries have more temperate climates than would be expected purely from their latitudes (relatively mild London, for example, lies more than 500 miles further north than Toronto).

But if the Atlantic Circumpolar Current is something like the Gulf Stream, there's a notable difference: it's even bigger.

"It's the largest ocean current today, and it's the only one that connects all the ocean basins," Scher says. "The Atlantic, Pacific and the Indian are huge oceans, but they're all bounded by continents; they have firm boundaries. The Southern Ocean, around Antarctica, is the only band of latitude where there's an ocean that goes continuously around the globe. Because of that, the winds that blow over the Southern Ocean are unimpeded by continental barriers.

"So the distance that the wind can blow over the ocean, which as oceanographers we call the 'fetch,' is infinite. And fetch is one of the things that determines how high the waves are, how much mixing goes on in the oceans, and ultimately what drives surface ocean currents. With infinite fetch, you can have a very strong ocean current, and because this particular band of ocean connects all of the world's oceans, it transports heat and salt and nutrients all around the world."

In a paper recently published in the journal Nature, Scher and his team make the case for just when this massive ocean current first started flowing. One straightforward obstacle in the distant past was the arrangement of continental masses. Antarctica and Australia were part of a single super-continent, Gondwana, and began to separate about 83 million years ago, so the Pacific and Indian Oceans couldn't have been in contact near the South Pole before then.

It was much later than the initial separation of Australia and Antarctica that deep ocean currents could flow between the two continents, though. Paleoceanographers have identified a transition, the opening of the Tasmanian gateway, a deep-water channel between Tasmania and Antarctica, as being a necessary part of any large-scale, sustained flow on the order of the Antarctic Circumpolar Current.

Using novel information about the separation of Antarctica and Australia, Scher and his team developed a tectonic model that showed that the Tasmanian gateway first developed at least 500 meters of depth some time between 35 and 32 million years ago.

From geochemical analyses of sediment core, however, they concluded that the channel opening to that depth wasn't enough to get the Antarctic Circumpolar Current flowing. The Pacific Ocean is in contact with much younger rock than the Indian Ocean, Scher says, which leads to a distinguishing concentration in each ocean of one isotope of neodymium that has a half-life longer than that of the solar system.

By measuring neodymium isotope compositions incorporated into fish teeth fossils in core samples, the team was able to establish that eastward current flow between the Pacific and Indian Oceans didn't begin until about 30 million years ago, some 2 to 5 million years after the Tasmanian gateway opened.

Taking both geophysical and geochemical data into account, they conclude that although the Tasmanian gateway was wide enough to accommodate a deep current, the gateway was located too far south to be in contact with the mid-latitude trade winds, which are the driving force for today's eastward-flowing Antarctic Circumpolar Current.

Instead, when the gateway first opened, water initially flowed westward, the opposite of that today, in keeping with the prevailing polar winds located at the more southern latitudes.

Only as both continents, and the gateway between the two, drifted northward on their tectonic plates over the next several million years did alignment with the trade winds come about. That reversed the current flow, to the east, and the Antarctic Circumpolar Current was born.

"It's the global mix-master of the oceans--that's a quote from Wally Broecker [of Columbia University's Lamont-Doherty Earth Observatory], and that's what it's been called by oceanographers for 50 years now," Scher says. "The Antarctic Circumpolar Current is the world's largest current today, it influences heat exchange and carbon exchange, and we really didn't know for how long it's been operating, which I call a major gap in our command of Earth history. It was a cool outcome."

Author: Steven Powell  | Source: University of South Carolina [August 25, 2015]

The build-up and subsequent release of warm, stagnant water from the deep Arctic Ocean and Nordic Seas played a role in ending the last Ice Age within the Arctic region, according to new research led by a UCL scientist.

The study, published today in Science, examined how the circulation of the ocean north of Iceland -- the combined Arctic Ocean and Nordic Seas, called the Arctic Mediterranean -- changed since the end of the last Ice Age (~20,000-30,000 years ago).

Today, the ocean is cooled by the atmosphere during winter, producing large volumes of dense water that sink and flush through the deep Arctic Mediterranean. However, in contrast to the vigorous circulation of today, the research found that during the last Ice Age, the deep Arctic Mediterranean became like a giant stagnant pond, with deep waters not being replenished for up to 10,000 years.

This is thought to have been caused by the thick and extensive layer of sea ice and fresh water that covered much of the Arctic Mediterranean during the Ice Age, preventing the atmosphere from cooling and densifying the underlying ocean.

Dr David Thornalley (UCL Geography) said: "As well as being stagnant, these deep waters were also warm. Sitting around at the bottom of the ocean, they slowly accumulated geothermal heat from the seafloor, until a critical point was reached when the ocean became unstable.

"Suddenly, the heat previously stored in the deep Arctic Mediterranean was released to the upper ocean. The timing of this event coincides with the occurrence of evidence for a massive release of meltwater into the Nordic Seas. We hypothesize that this input of melt water was caused by the release of deep ocean heat, which melted icebergs, sea-ice and surrounding marine-terminating ice sheets."

This study highlights the important impact that changes in ocean circulation can have on climate, due to the ocean's capacity to redistribute vast quantities of heat around the globe. For example, scientists are currently concerned that ongoing changes in ocean circulation may result in warmer subsurface water that will cause enhanced melting and retreat of certain ice sheets in Greenland and Antarctica.

Dr Thornalley added: "To help predict the role of the ocean in future climate change, it is useful to investigate how ocean circulation changed in the past and what the associated climate effects were."

In this study, researchers from UCL, Woods Hole Oceanographic Institute and other partner institutions analysed the composition of calcite shells of small single-celled organisms (called foraminifera) that are found in ocean floor sediment. The shells of these organisms record the chemistry of the deep ocean at the time they were living, enabling the researchers to reconstruct past changes in ocean circulation.

By measuring the radiocarbon content of these shells, the research team was able to determine how rapidly deep water was being formed in the Arctic Mediterranean. A number of different techniques were then used to constrain past temperature changes, including measuring the ratio of magnesium and calcium, and the arrangement of isotopes of carbon and oxygen within the calcite shells of the foraminifera, both of which vary according to the temperature of the water in which the foraminifera grew.

A warmer, deep Arctic Mediterranean during glacial times has been suggested in previous studies, too. As summarised by co-author Dr Henning Bauch (GEOMAR/Germany) "It is good to see that new, independent proxy data would give strong support now to these former hypotheses."

Source: University College London [August 13, 2015]

Researchers from CSIRO and Imperial College London have assessed how widespread the threat of plastic is for the world's seabirds, including albatrosses, shearwaters and penguins, and found the majority of seabird species have plastic in their gut.

The study, led by Dr Chris Wilcox with co-authors Dr Denise Hardesty and Dr Erik van Sebille and published today in the journal PNAS, found that nearly 60 per cent of all seabird species have plastic in their gut.

Based on analysis of published studies since the early 1960s, the researchers found that plastic is increasingly common in seabird's stomachs.

In 1960, plastic was found in the stomach of less than 5 per cent of individual seabirds, rising to 80 per cent by 2010.

The researchers predict that plastic ingestion will affect 99 per cent of the world's seabird species by 2050, based on current trends.

The scientists estimate that 90 per cent of all seabirds alive today have eaten plastic of some kind.

This includes bags, bottle caps, and plastic fibres from synthetic clothes, which have washed out into the ocean from urban rivers, sewers and waste deposits.

Birds mistake the brightly coloured items for food, or swallow them by accident, and this causes gut impaction, weight loss and sometimes even death.

"For the first time, we have a global prediction of how wide-reaching plastic impacts may be on marine species -- and the results are striking," senior research scientist at CSIRO Oceans and Atmosphere Dr Wilcox said.

"We predict, using historical observations, that 90 per cent of individual seabirds have eaten plastic. This is a huge amount and really points to the ubiquity of plastic pollution."

Dr Denise Hardesty from CSIRO Oceans and Atmosphere said seabirds were excellent indicators of ecosystem health.

"Finding such widespread estimates of plastic in seabirds is borne out by some of the fieldwork we've carried out where I've found nearly 200 pieces of plastic in a single seabird," Dr Hardesty said.

The researchers found plastics will have the greatest impact on wildlife where they gather in the Southern Ocean, in a band around the southern edges of Australia, South Africa and South America.

Dr van Sebille, from the Grantham Institute at Imperial College London, said the plastics had the most devastating impact in the areas where there was the greatest diversity of species.

"We are very concerned about species such as penguins and giant albatrosses, which live in these areas," Erik van Sebille said.

"While the infamous garbage patches in the middle of the oceans have strikingly high densities of plastic, very few animals live here."

Dr Hardesty said there was still the opportunity to change the impact plastic had on seabirds.

"Improving waste management can reduce the threat plastic is posing to marine wildlife," she said.

"Even simple measures can make a difference. Efforts to reduce plastics losses into the environment in Europe resulted in measureable changes in plastic in seabird stomachs with less than a decade, which suggests that improvements in basic waste management can reduce plastic in the environment in a really short time."

Chief Scientist at the US-based Ocean Conservancy Dr George H. Leonard said the study was highly important and demonstrated how pervasive plastics were in oceans.

"Hundreds of thousands of volunteers around the world come face-to-face with this problem during annual Coastal Cleanup events," Dr Leonard said.

"Scientists, the private sector and global citizens working together against the growing onslaught of plastic pollution can reduce plastic inputs to help protect marine biodiversity."

Source: CSIRO Australia [September 01, 2015]