6.24.2011

'Shocking' state of seas threatens mass extinction, say marine experts


Overfishing and pollution putting fish, sharks and whales in extreme danger – with extinction 'inevitable', study finds

Fish, sharks, whales and other marine species are in imminent danger of an "unprecedented" and catastrophic extinction event at the hands of humankind, and are disappearing at a far faster rate than anyone had predicted, a study of the world's oceans has found.

Mass extinction of species will be "inevitable" if current trends continue, researchers said.

Overfishing, pollution, run-off of fertilisers from farming and the acidification of the seas caused by increasing carbon dioxide emissions are combining to put marine creatures in extreme danger, according to the report from the International Programme on the State of the Ocean (Ipso), prepared at the first international workshop to consider all of the cumulative stresses affecting the oceans at Oxford University.

The international panel of marine experts said there was a "high risk of entering a phase of extinction of marine species unprecedented in human history". They said the challenges facing the oceans created "the conditions associated with every previous major extinction of species in Earth's history".

"The findings are shocking," said Alex Rogers, scientific director of Ipso. "As we considered the cumulative effect of what humankind does to the ocean, the implications became far worse than we had individually realised. This is a very serious situation demanding unequivocal action at every level. We are looking at consequences for humankind that will impact in our lifetime, and worse, our children's and generations beyond that."

The flow of soil nutrients into the oceans is creating huge "dead zones", where anoxia - the absence of oxygen - and hypoxia - low oxygen levels - mean fish and other marine life are unable to survive there.

Hypoxia and anoxia, warming and acidification are factors present in every mass extinction event in the oceans over the Earth's history, according to scientific research. About 55m years ago, as much as half of some species of deep-sea creatures were wiped out when atmospheric changes created similar conditions.

In recent years, human effects on the oceans have increased significantly. Overfishing has cut some fish populations by more than 90%. Pollutants, including flame-retardant chemicals and detergents are absorbed into particles of plastic waste in the sea, which are then ingested by marine creatures. Millions of fish, birds and other forms of life are choked or suffer internal ruptures from ingesting plastic waste.

During 1998, record high temperatures wiped out about 16% of the world's tropical coral reefs.

The scientists called on the United Nations and governments to bring in measures to conserve marine ecosystems. Dan Laffoley, of the International Union for the Conservation of Nature, said: "The world's leading experts on oceans are surprised by the rate and magnitude of changes we are seeing. The challenges for the future of the oceans are vast, but unlike previous generations we know what now needs to happen. The time to protect the blue heart of our planet is now, today and urgent".

Source: http://www.guardian.co.uk/environment/2011/jun/20/marine-life-oceans-extinction-threat#


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6.10.2011

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ScienceDaily
— The present rate of greenhouse carbon dioxide emissions through fossil fuel burning is higher than that associated with an ancient episode of severe global warming, according to new research. The findings are published online this week by the journal Nature Geoscience.

Around 55.9 million years ago, Earth experienced a period of intense global warming known as the Palaeocene-Eocene Thermal Maximum (PETM), which lasted for around 170,000 years. During its main phase, average annual temperatures rose by around 5°C.

Scientists believe that the warming may have been initially triggered by an event such as the baking of organic-rich sediments by igneous activity that released the potent greenhouse gas, methane. This initial temperature increase warmed ocean bottom waters which allowed the break down of gas hydrates (clathrates), which are found under deep ocean sediments: this would have greatly amplified the initial warming by releasing even more vast volumes of methane. As the methane diffused from the seawater into the atmosphere it would have been oxidised to form carbon dioxide, another potent and longer-lived greenhouse gas.

Adam Charles and his PhD supervisor, Dr Ian Harding, both palaeoceanographers at the University of Southampton's School of Ocean and Earth Science (SOES) based at the National Oceanography Centre, Southampton, co-authored the report. Dr Harding said: "The PETM has been seen by many as a natural test bed for understanding modern human-made global warming, despite it not being a perfect analogy. However, the total amount of carbon released during this climatic perturbation and its rate of release have been unclear."

To help fill this gap in knowledge, the researchers measured carbon isotope ratios of marine organic matter preserved in sediments collected in Spitsbergen. The sedimentary section is important because it records the entirety of the PETM, from its initiation to through the recovery period, and as such is the most complete record of the warming event so far known in high northern latitudes.

Based on their carbon isotope measurements and computer simulations of Earth system, the researchers estimated that the rate of carbon emissions during the PETM peaked at between 300 million and 1,700 million metric tonnes per year, which is much slower than the present carbon emission rate.

"Our findings suggest that humankind may be causing atmospheric carbon dioxide to increase at rates never previously seen on Earth, which would suggest that current temperatures will potentially rise much faster than they did during the PETM," concluded Dr Harding.

This research was supported by The Worldwide Universities Network, Pennsylvania State University, and the US National Science Foundation.

Source: http://www.sciencedaily.com/releases/2011/06/110607121525.htm


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5.18.2011

Florida may limit soft coral harvest



Divers who collect fish and coral off South Florida's coast for the domestic and international aquarium trade face potential limits on the number of sea fans, sea whips and other soft corals they can harvest — potentially curbing business for the divers and the availability for consumers' aquariums.

Soft corals, also known as octocoral or gorgonian, are marine animals shaped like flowers, feathers and fans. Spread across the ocean floor like grass in a field, they consist of tiny polyps that use tentacles to catch prey. They are rarely eaten by sea animals, because they produce chemicals that taste bad to other marine organisms.

Divers explore the reefs off South Florida for octocorals, and transport them to aquarium supply shops and private customers all over the world. Octocorals are very popular in reef aquariums, because they bring diversity to the environment.

According to the Florida Fish and Wildlife Conservation Commission, 62 commercial harvesters landed octocorals last year; the number of harvesters is capped at 167.

The 25 or so species of most commonly harvested include purple sea blades and sea whips, with prices ranging from $15 to $69.99.

"The Gulf of Mexico Fishery Management Council intends to remove octocoral from its Coral and Coral Reef Fishery Management Plan," said Martha Bademan, of the FWC, which is planning to put restrictions on octocoral harvests. "So the FWC has agreed to manage the fishery in both state and federal waters."

Currently, there is a 50,000 colony quota in place for federal waters, the measure used in keeping track of how much is harvested, and no quota for state waters. The FWC is considering a quota of 70,000 colonies for state and federal waters combined. The FWC staff working on the proposal will present recommendations to June 8 and 9.

A final public hearing will be held in September at the FWC meeting in Naples, after which the agreed-upon harvest quota will take effect.

What impact would the limit have on divers?

"None as long as it is not lowered," said Tom Scaturro, owner of Tom's Caribbean Tropicals of Tavernier in the Florida Keys. "They are trying to lower the limit because we have never reached the limit before. We do not want that."

Michael Helmholtz, who works as a gorgorian collector at the Florida Marine Life Collectors, argues that with an estimated 8 billion to 28.8 billion octocoral colonies in the Florida Keys alone, the supply of octocoral cannot be exhausted.

"If you divide the number of divers by gorgonians, you discover that there are lots more than we can collect in one year," he said.

Henry Feddern, a commercial marine-life collector with 50 years of experience, thinks an octocoral harvest of 70,000 colonies is not out of place.

"This would be more than enough for the foreseeable future and not appreciably affect the octocoral population," he said. "Catching 70,000 colonies a year probably has the same effect on the octocoral population as plucking a few blades of grass has on a large lawn."

Source: http://www.sun-sentinel.com/news/palm-beach/fl-coral-harvest-20110514,0,3748310.story

xcxsadeoye@sun-sentinel.com, 954-300-9761



About Oceanic Defense
We are an international organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

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