Category Archives: oceans

Dramatic climate swings likely as world warms: Ancient El Niño clue to future floods

Dramatic climate swings likely as world warms: Ancient El Niño clue to future floods.

ScienceDaily (July 14, 2011) — Dramatic climate swings behind both last year’s Pakistan flooding and this year’s Queensland floods in Australia are likely to continue as the world gets warmer, scientists predict.

Researchers at the Universities of Oxford and Leeds have discovered that the El Niño Southern Oscillation (ENSO), the sloshing of the warmest waters on the planet from the West Pacific towards the East Pacific every 2-7 years, continued during Earth’s last great warm period, the Pliocene.

Their results suggest that swings between the two climatic extremes, known as El Niño and La Niña, may even have occurred more frequently in the warmer past and may increase in frequency in the future. Extreme ENSO events cause droughts, forest fires and floods across much of the world as well as affecting fishery production.

Reporting in the journal Paleoceanography, the team of geochemists and climate modellers use the Pliocene as a past analogue and predictor of the workings of Earth’s future climate.

The Pliocene (which lasted from 5 to 3 million years ago) had carbon dioxide levels similar to the present day, with global mean temperatures about 2-3ºC higher, so it is a useful test-ground for climate research.

Lead Scientist Nick Scroxton from Oxford University’s Department of Earth Sciences said: ‘We know from previous studies that the mean state of the Pacific during the warm Pliocene was similar to the climate patterns observed during a typical El Niño event that we see today.

‘However, until recently it was believed that a warmer Pacific would reduce the climate swings that cause the dramatic weather extremes throughout the region leading to a permanent state of El Niño. What we didn’t expect was that climatic variability would remain strong under these warmer conditions.’

The team combined experiments performed on the Met Office Hadley Centre climate model, HadCM3, with the analysis of the chemical composition of lots of individual shells of small organisms, known as foraminifera.

These were collected from a deep sea sediment core in the East Equatorial Pacific, and provided a record of temperature in the upper layer of the ocean through time. They discovered that the range of temperatures experienced by these organisms during the Pliocene, was higher than what would be expected from just the seasonal cycle.

The extra variation in temperature can be explained by the additional extreme temperature swings provided by the El Niño/La Niña system.

The authors say the agreement in findings from both ocean data and modelling leaves little doubt that ENSO will persist in a warmer world. Earlier this year a team from Japan studying corals from the same period showed climatic variability in the western Pacific on a similar scale to today, questioning the idea of a permanent El Niño during the Pliocene.

This new study goes further, showing that the oscillation is Pacific-wide, and is likely to be caused by the El Niño/La Niña. This suggests that our warmer future will continue to be dogged, maybe even more regularly, by extreme climatic events.

Warming oceans cause largest movement of marine species in 2m years

Warming oceans cause largest movement of marine species in two million years – Telegraph.

Swarms of venomous jelly fish and poisonous algae are migrating into British waters due to changes in the ocean temperatures, a major new study has revealed.

Warming oceans causing largest movement of marine species in two million years

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The venomous warm-water species Pelagia noctiluca  Photo: ALAMY
A Pacific grey whale was sighted in the Meditteranean after swimming through a passage that melted in the Arctic sea ice

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A Pacific grey whale was sighted in the Mediterranean after swimming through a passage that melted in the Arctic sea ice

Warming ocean waters are causing the largest movement of marine species seen on Earth in more than two million years, according to scientists.

In the Arctic, melting sea ice during recent summers has allowed a passage to open up from the Pacific ocean into the North Atlantic, allowing plankton, fish and even whales to into the Atlantic Ocean from the Pacific.

The discovery has sparked fears delicate marine food webs could be unbalanced and lead to some species becoming extinct as competition for food between the native species and the invaders stretches resources.

Rising ocean temperatures are also allowing species normally found in warmer sub-tropical regions to into the northeast Atlantic.

A venomous warm-water species Pelagia noctiluca has forced the closure of beaches and is now becoming increasingly common in the waters around Britain.

The highly venomous Portuguese Man-of-War, which is normally found in subtropical waters, is also regularly been found in the northern Atlantic waters.

A form of algae known as dinoflagellates has also been found to be moving eastwards across the Atlantic towards Scandinavia and the North Sea.

Huge blooms of these marine plants use up the oxygen in the water and can produce toxic compounds that make shellfish poisonous.

Plankton sampling in the north Atlantic over the past 70 years have also shown that other species of plankton, normally only found in the Pacific ocean, have now become common in Atlantic waters.

The scientists, who have been collaborating on the Climate Change and European Marine Ecosystems Research project, found the plankton species, called Neodenticula seminae, traveled into the Atlantic through a passage through the Arctic sea ice around that has opened up a number of times in the last decade from the Pacific Ocean.

Larger species including a grey whale have also been found to have made the journey through the passage, which winds it’s way from the Pacific coast of Alaska through the islands of northern Canada and down past Greenland into the Atlantic Ocean, when it opened first in 1998, and then again in 2007 and 2010.

Professor Chris Reid, from the Sir Alister Hardy Foundation for Ocean Science at the Plymouth Marine Laboratory, said: “It seems for the first time in probably thousands of years a huge area of sea water opened up between Alaska and the west of Greenland, allowing a huge transfer of water and species between the two oceans.

“The opening of this passage allowed the wind to drive a current through this passage and the water warmed up making it favourable for species to get through.

“In 1999 we discovered a species in the north west Atlantic that we hadn’t seen before, but we know from surveys in the north Pacific that it is very abundant there.

“This species died out in the Atlantic around 800,000 years ago due to glaciation that changed the conditions it needed to survive.

“The implications are huge. The last time there was an incursion of species from the Pacific into the Atlantic was around two to three million years ago.

“Large numbers of species were introduced from the Pacific and made large numbers of local Atlantic species extinct.

“The impact on salmon and other fish resources could be very dramatic. The indications are that as the ice is continuing to melt in the summer months, climate change could lead to complete melting within 20 to 30 years, which would see huge numbers of species migrating.

“It could have impacts all the way down to the British Isles and down the east coast of the United States.”

He added: “With the jellyfish we are seeing them move further north from tropical and subtropical regions as a result of warming sea temperatures.”

Researchers say the invading plankton species is likely to cause widespread changes to the food web in the Atlantic ocean as the invading species are less nutritious than native species, which are eaten by many fish and large whales.

Changes in populations of tiny animals called copepods, which are an essential food source for fish such as cod, herring and mackerel, are already being blamed for helping to drive the collapse of fish stocks as the native species of copepods have been replaced with smaller less nutritious varieties.

This has resulted in declines in North Sea birds, the researchers claim, while Harbour porpoises have also migrated northwards North Sea after sand eels followed the poleward movement of the copepods they ate.

Scientists taking part in the project from the Institute for Marine Resources & Ecosystem Studies, in the Netherlands, found that warmer water would also lead more species in the North and Irish sea as species move from more southerly areas.

But they found that the Atlantic ocean west of Scotland would have fewer species.

Dr Carlo Heip, director general of the Royal Netherlands Institute for Sea Research, which led the project that is a collaboration of more than 17 institutes in 10 different countries, said: “We need to learn much more about what’s happening in Europe’s seas, but the signs already point to far more trouble than benefit from climate change.

“Despite the many unknowns, it’s obvious that we can expect damaging upheaval as we overturn the workings of a system that’s so complex and important.

“The migrations are an example of how changing climate conditions cause species to move or change their behaviour, leading to shifts in ecosystems that are clearly visible.”

The researchers conclude that these changes will have serious implications for commercial fisheries and on the marine environment.

Among the other species to have migrated from the Pacific Ocean into the Atlantic was a grey whale that was spotted as far south as the Mediterrean off the coast of Spain and Israel.

Grey whales have been extinct in the Atlantic Ocean for more than a hundred years due to hunting and scientists found the animal had crossed through openings in the Arctic sea ice.

Dr Katja Philippart, from the Royal Netherland’s Institute for Sea Research, added: “We have seen very small plankton and large whales migrating from the Pacific into the North Atlantic, so there will certainly be many other species, including fish, that we haven’t detected yet.

“To see a whale in this part of the world was quite remarkable and when we looked at it we concluded it can only have come from one place.”

Can’t Eliminate an Invasive Species? Try Eating It!

Can’t Eliminate an Invasive Species? Try Eating It. – NYTimes.com.

Erik Olsen/The New York Times

Although the lionfish appears off-putting, some see a growing place for it on American plates.”

With its dark red and black stripes, spotted fins and long venomous black spikes, the lionfish seems better suited for horror films than consumption. But lionfish fritters and filets may be on American tables soon.

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Ty Cacek/The New York Times

Some invaders have successfully been turned into food, like tilapia.

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Vone Research/Lionfishhunters.Org

Among the less endearing qualities of the lionfish are their venomous spines.

An invasive species, the lionfish is devastating reef fish populations along the Florida coast and into the Caribbean. Now, an increasing number of environmentalists, consumer groups and scientists are seriously testing a novel solution to control it and other aquatic invasive species — one that would also takes pressure off depleted ocean fish stocks: they want Americans to step up to their plates and start eating invasive critters in large numbers.

“Humans are the most ubiquitous predators on earth,” said Philip Kramer, director of the Caribbean program for the Nature Conservancy. “Instead of eating something like shark fin soup, why not eat a species that is causing harm, and with your meal make a positive contribution?”

Invasive species have become a vexing problem in the United States, with population explosions of Asian carp clogging the Mississippi River and European green crabs mobbing the coasts. With few natural predators in North America, such fast-breeding species have thrived in American waters, eating native creatures and out-competing them for food and habitats.

While most invasive species are not commonly regarded as edible food, that is mostly a matter of marketing, experts say. Imagine menus where Asian carp substitutes for the threatened Chilean sea bass, or lionfish replaces grouper, which is overfished.

“We think there could be a real market,” said Wenonah Hauter, the executive director of Food and Water Watch, whose 2011 Smart Seafood Guide recommends for the first time that diners seek out invasive species as a “safer, more sustainable” alternative to their more dwindling relatives, to encourage fisherman and markets to provide them.

“What these species need now is a better — sexier — profile, and more cooks who know how to use them,” she said. She has enlisted celebrity chefs to promote eating the creatures.

Scientists emphasize that human consumption is only part of what is needed to control invasive species and restore native fish populations, and that a comprehensive plan must include restoring fish predators to depleted habitats and erecting physical barriers to prevent further dissemination of the invaders.

“We are not going to be able to just eat our way out of the invasive species problem,” Dr. Kramer said. “On the other hand, there are places where this can be a very useful part of the strategy.”

The United States Fish and Wildlife Service is now exploring where it might be helpful. Models suggest that commercial harvest of Asian carp in the Mississippi would most likely help control populations there, “as part of an integrated pest management program,” said Valerie Fellows, a spokeswoman.

In practice, it is still unclear whether commercial fishing pressure could be high enough to have a significant impact, she said. The Army Corps of Engineers has spent millions of dollars to erect electronic barriers to keep Asian carp from moving from the Illinois River into the Great Lakes.

There are risks to whetting America’s appetite. Marketing an invasive species could make it so popular that “individuals would raise or release the fish” where they did not already exist, Ms. Fellows said, potentially exacerbating the problem; tilapia were originally imported into Latin America for weed and bug control, but commercialization helped the species spread far more widely than intended.

Dr. Kramer is concerned that the marketing of lionfish might increase the number of traps on reefs, which could trap other fish as well. He said spearfishing was the sustainable way to catch lionfish, which are reef dwellers.

Cookbooks do not say much about how to filet an Asian carp, which has an unusual bony structure. And even if one developed a taste for, say, European green crab soup, there is nowhere to buy the main ingredient, though it is plentiful in the sea.

To increase culinary demand, Food and Water Watch has teamed up with the James Beard Foundation and Kerry Heffernan, the chef at the South Gate restaurant in New York City, to devise recipes using the creatures. At a recent tasting, there was Asian carp ceviche and braised lionfish filet in brown butter sauce.

Lionfish, it turns out, looks hideous but tastes great. The group had to hire fishermen to catch animals commonly regarded as pests. Mr. Heffernan said he would consider putting them on his menu and was looking forward to getting some molting European green crabs to try in soft-shell crab recipes.

Last summer, the Nature Conservancy sponsored a lionfish food fair in the Bahamas, featuring lionfish fritters and more. They offered fishermen $11 a pound — about the price of grouper — and got an abundant supply. Lionfish, native to the Indian Ocean and South Pacific, arrived in the Caribbean in the early 1990s and are spreading rapidly; voracious eaters, they even eat juveniles of native fish.

Lionfish, like grouper, can carry ciguatoxin, which causes vomiting and neurological symptoms, so they cannot be taken from water where the microbe that produces the toxin is found. The fish’s venomous spines must be removed before sale, although that is not a serious marketing obstacle.

Mitchell Davis, vice president of the Beard Foundation, said other species had moved from being pariah pests to must-have items on American plates, like dandelion greens for salads.

Earth's oceans on course for mass extinction

Earth’s oceans on course for mass extinction – environment – 21 June 2011 – New Scientist.

Mass extinctions are seldom pretty, but this one would transform Earth’s oceans forever, especially coral reefs.

A new report by the International Programme on the State of the Ocean (IPSO) assesses how climate change, overexploitation, pollution, habitat loss and other stressors are affecting the ocean as a whole.

The conclusion? We’re on course for a mass extinction that would include coral reefs and the menagerie of species that rely on them, as well as multiple species of fish consumed by people, although it may not be as severe as the “big five” extinctions of Earth’s distant past.

“We’re seeing a combination of symptoms that have been associated with large, past extinctions,” says Alex Rogers, the head of IPSO.

Acidifying waters

Rogers says the biggest problem is the rapid pace of climate change, which is “virtually unprecedented”. The closest comparison is the Paleocene-Eocene Thermal Maximum of 55 million years ago, when 2.2 gigatonnes of carbon dioxide was released every year for millennia and many deep-sea species were wiped out. Today we release over 25 gigatonnes every year.

Many harmful factors combine to cause additional damage. For instance, the oceans are acidifying as a result of CO2 dissolving in the water, and this makes corals more susceptible to “bleaching”.

Rogers recommends nothing less than slashing CO2 emissions, establishing Marine Protected Areas covering up to one-third of the ocean, and restoring marine ecosystems.

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