Oceans face 'deadly trio' of threats, study says

A whale dives into sea off the coast of Greenland's capital Nuuk October 17, 2012.

Credit: Reuters/Alistair Scrutton

By Environment Correspondent Alister Doyle

OSLO | Thu Oct 3, 2013 4:56am EDT

OSLO (Reuters) - The world's oceans are under greater threat than previously believed from a "deadly trio" of global warming, declining oxygen levels and acidification, an international study said on Thursday.

The oceans have continued to warm, pushing many commercial fish stocks towards the poles and raising the risk of extinction for some marine species, despite a slower pace of temperature rises in the atmosphere this century, it said.

"Risks to the ocean and the ecosystems it supports have been significantly underestimated," according to the International Programme on the State of the Ocean (IPSO), a non-governmental group of leading scientists.

"The scale and rate of the present day carbon perturbation, and resulting ocean acidification, is unprecedented in Earth's known history," according to the report, made with the International Union for Conservation of Nature.

The oceans are warming because of heat from a build-up of greenhouse gases in the atmosphere. Fertilizers and sewage that wash into the oceans can cause blooms of algae that reduce oxygen levels in the waters. And carbon dioxide in the air can form a weak acid when it reacts with sea water.

"The ‘deadly trio' of ... acidification, warming and deoxygenation is seriously affecting how productive and efficient the ocean is," the study said.

Alex Rogers of Oxford University, scientific director of IPSO, told Reuters scientists were finding that threats to the oceans, from the impacts of carbon to over-fishing, were compounding one another.

"We are seeing impacts throughout the world," he said.

EXTINCTIONS

Current conditions in the oceans were similar to those 55 million years ago, known as the Paleocene-Eocene thermal maximum, that led to wide extinctions. And the current pace of change was much faster and meant greater stresses, Rogers said.

Acidification, for instance, threatens marine organisms that use calcium carbonate to build their skeletons - such as reef-forming corals, crabs, oysters and some plankton vital to marine food webs.

Corals might cease to grow if temperatures rose by 2 degrees Celsius (3.6F) and start to dissolve at 3 degrees (5.4F), the study said.

Scientists said the findings added urgency to a plan by almost 200 governments to work out a deal by the end of 2015 to limit a rise in average world temperatures to less than 2 degrees Celsius (3.6F) above pre-industrial times.

Temperatures have already risen by about 0.8 degree Celsius (1.4F). The report also urged tougher management of fish stocks including a ban on destructive bottom trawlers and granting more power to local communities in developing nations to set quotas.

Last week, a report by the U.N.'s Intergovernmental Panel on Climate Change (IPCC) raised the probability that mankind was the culprit for most global warming to 95 percent, from 90 in a report in 2007.

The Global Ocean Commission, a group of politicians working to advise governments, urged stronger action.

"If the IPCC report was a wake-up call on climate change, IPSO is a deafening alarm bell on humanity's wider impacts on the global ocean," said Trevor Manuel, co-chair of the Commission and minister in the South African Presidency.

(Reporting By Alister Doyle, editing by Elizabeth Piper)

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Safety reflector technology from footwear getting new life in detecting bioterror threats

Tiny versions of the reflectors on sneakers and bicycle fenders that help ensure the safety of runners and bikers at night are moving toward another role in detecting bioterrorism threats and diagnosing everyday infectious diseases, scientists said today.

Their report on progress in using these innovative "retroreflectors"—the same technology that increases the night-time visibility of traffic signs—was among almost 12,000 on the agenda of the 245th National Meeting & Exposition of the American Chemical Society.

"Our goal is the development of an ultrasensitive, all-in-one device that can quickly tell first-responders exactly which disease-causing microbe has been used in a bioterrorism attack," said Richard Willson, Ph.D., who leads the research. "In the most likely kind of attack, large numbers of people would start getting sick with symptoms that could be from multiple infectious agents. But which one? The availability of an instrument capable of detecting several agents simultaneously would greatly enhance our response to a possible bioterror attack or the emergence of a disease not often seen here."

Willson's team is developing another version of the technology intended for use in doctors' offices and clinics for rapid, on-site diagnosis of common infectious diseases before patients leave. Eliminating the need to wait for test results from an outside laboratory could allow patients to get the right treatment sooner and recover sooner, Willson noted.

One of those tests focuses on detecting norovirus, the dreaded "cruise ship virus," or "winter vomiting virus," which strikes more than 20 million people annually in the United States alone. Norovirus was in the headlines last December when it struck 220 people on the Queen Mary II.

Balakrishnan Raja, the member of Willson's team at the University of Houston (UH) who presented the report, pointed out that retroreflectors may be the most visually detectable devices ever made by humanity. They work on the project with colleagues at UH, the University of Texas Medical Branch in Galveston and the Sandia National Laboratories branch in Livermore, Calif. The devices reflect light directly back to its source in a way that produces extreme brightness. One version of retroreflection effect occurs when someone shines a flashlight in a mirror. The reflection is so bright that looking at it hurts.

Although most people have never heard the term "retroreflector," these devices are not new, Raja pointed out. The Apollo 11 astronauts, for instance, left a laser-ranging retroreflector on the moon during the first lunar landing mission in 1969. Scientists still use the device to study the moon's orbit. And they are ubiquitous fixtures in road signs, traffic lane markers and elsewhere in everyday life.

Willson's collaborator Paul Ruchhoeft of UH has developed a way of making retroreflectors so small that more than 200 would fit inside the period at the end of this sentence. The retroreflectors then become part of a lab-on-a-chip, or a microfluidic device, with minute channels for processing "microliter"-scale amounts of blood or other fluids. A microliter is one-millionth of a liter (a liter is about one quart). A drop of water contains about 50 microliters.

When a sample of fluid that doesn't contain disease-causing viruses or bacteria flows through those channels to the retroreflectors, they shine brightly. A sample containing bacteria, however, makes portions of the reflectors go dark, signaling a positive test result. Raja explained that the change from bright to dark is one of several advantages of the retroreflector technology, compared to existing ways of detecting disease-causing microbes. It can be detected with simple optical devices, rather than expensive, complex optics. The retroreflector technology also avoids the need to specially prepare samples for analysis and is faster.

"Right now, we have seven channels in our device," Raja said. "So we can test for seven different infections at once, but we could make more channels. That's one of our long-term goals—to multiplex the device and detect many pathogens at once."

They have demonstrated clinically useful sensitivity on samples containing Rickettsia conorii, a bioterrorism threat that causes Mediterranean spotted fever, and others are on the agenda. A new version of the technology involves retroreflector cubes that can be suspended in samples of fluid. Willson's team initially will use it on norovirus with the goal of developing a device that can raise a red flag on norovirus viral contamination and prevent the disease's wildfire-like spread.

More information: Abstract

Ultrasensitive and rapid pathogen detection generally relies on nucleic acid extraction followed by amplification, or labeling with dyes, enzymes or fluors, which require elaborate instrumentation. This work introduces embedded, microfabricated linear retroreflectors as bio-sensing surfaces, using micron-sized magnetic particles as light-blocking labels in a highly sensitive diagnostic immunoassay. Retroreflectors return light directly to its source and are easily detectable using inexpensive optics. The pathogen is immunocaptured by a sensing surface following immunomagnetic separation and concentration from a complex sample. An automated difference imaging algorithm that detects single 3.0 µm magnetic particles without optical calibration is used to quantify the number of labels bound to each from each 1 sq. mm. array of retroreflectors. An assay for the detection of Rickettsia conorii is implemented in a microfluidic format with fluidic force discrimination to enhance reproducibility and specificity, with a current limit of detection of less than 4000 bacteria per mL.

Provided by American Chemical Society

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