Thursday, September 12, 2013

Antarctica Fossil DNA Related to the Most Ancient Organisms Known on Earth

The possibility that extreme life forms might exist in the cold and dark lakes hidden kilometers beneath the Antarctic ice sheet has fascinated scientists for decades. Now, evidence of diverse life forms dating back nearly a hundred thousand years has been found in subglacial lake sediments by a group of British scientists.

Scientists from the British Antarctic Survey (BAS), and the Universities of Northumbria and Edinburgh have been searching the retreating margins of the ice sheet for subglacial lakes that are becoming exposed for the first time since they were buried more than 100,000 years ago.

Some of the life discovered was in the form of Fossil DNA showing that many different types of bacteria live there, including a range of extremophiles which are species adapted to the most extreme environments. These use a variety of chemical methods to sustain life both with and without oxygen. Scientists believe organisms living in subglacial lakes could hold clues for how life might survive on other planets.

One DNA sequence was related to the most ancient organisms known on Earth and parts of the DNA in twenty three percent has not been previously described. Many of the species are likely to be new to science making clean exploration of the remote lakes isolated under the deeper parts of the ice sheet even more pressing.


This is because parts of the ice sheet are melting and retreating at unprecedented rates as the temperature rises at the poles.The group targeted Lake Hodgson on the Antarctic Peninsula which was covered by more than 400 m of ice at the end of the last Ice Age, but is now considered to be an emerging subglacial lake, with a thin covering of just 3-4 metres of ice.

Drilling through the ice they used clean coring techniques to delve into the sediments at the bottom of the lake which is 93 metres deep and approximately 1.5 km long by 1.5 km wide.

The lake was thought to be a harsh environment for any form of life but the layers of mud at the bottom of the lake represent a time capsule storing the DNA of the microbes which have lived there throughout the millennia. The top few centimetres of the core contained current and recent organisms which inhabit the lake but once the core reached 3.2 m deep the microbes found most likely date back nearly 100,000 years.

What was surprising was the high biomass and diversity found. This is the first time microbes have been identified living in the sediments of a subglacial Antarctic lake and indicates that life can exist and potentially thrive in environments we would consider too extreme.

The fact these organisms have survived in such a unique environment could mean they have developed in unique ways which could lead to exciting discoveries for us. This is the early stage and we now need to do more work to further investigate these life forms.

Late last year a British expedition to drill into Lake Ellsworth was called off after technical difficulties. A US expedition sampled a subglacial environment near the edge of the ice sheet but has yet to report its findings, and a Russian led project has sampled ice near the surface of a subglacial lake and has reported finding signs of life.

The paper, Preliminary Analysis of Life within a Former Subglacial Lake Sediment in Antarctica has been published online in the Journal 'Diversity' as part of a special issue on Microbial Ecology and Diversity.

[Source] British Antarctic Survey via The Daily Galaxy

[Image Credits] With thanks to BBC and Allison Murray

Wednesday, September 11, 2013

Marine Ecosystem Depends on the Fate of Pacific Forage Fish

This is a guest post from Lee Crockett, director of U.S. fisheries campaigns for The Pew Charitable Trusts.

My time at the National Oceanic and Atmospheric Administration (NOAA) and on Capitol Hill taught me that planning ahead and being proactive pays off when it comes to managing our nation’s fisheries. The Pacific Fishery Management Council could get ahead of the curve in September, when it will weigh the fate of forage fish.

As I’ve discussed previously, these types of small fish, such as sardines and anchovies, serve as an essential source of nourishment for larger fish, including the wild salmon and tuna that are popular with anglers, chefs and consumers. Forage fish also are consumed by other wildlife, from whales to seabirds, making them a vital part of the marine food web.

The Pacific council recently acted to protect an important species of forage fish, Pacific saury, by recommending that NOAA establish interim protection for them. The action sets the stage for the council to begin enacting longer-term protections for these and other forage fish that are not now included in a federal fisheries management plan.

In September, the council has a great opportunity to begin establishing long-term protection for important forage species that are not yet being fished. These species, which include sand lance and various kinds of smelts, are fished extensively elsewhere in the world and are used in a variety of products, such as feed for livestock and farmed fish. Protecting them will give policymakers a chance to analyze the potential impact on marine ecosystems to determine whether industrial-scale fishing can begin.

The Pacific council, which is on record as recognizing the importance of forage fish to marine ecosystems, set a goal of prohibiting unregulated fishing for these species in Pacific waters. I hope that they will now translate that goal into strong regulatory protection. After all, placing vulnerable forage species into an appropriate fishery management plan is the simplest way to prohibit new forage fisheries until the council can evaluate how removing prey would affect larger fish and the overall resilience of marine ecosystems.

Bringing important forage species under management before commercial fishing begins, rather than reacting to problems after the fact, is an approach with widespread public support. Over the past two years, the council heard from organizations representing the commercial fishing industry, sport fishermen, seafood suppliers, eco-tourism businesses, birding organizations, elected leaders and conservation groups from around the region. All called for stronger safeguards for forage species.

The council also received more than 50,000 comments from the general public encouraging protection of forage fish as a crucial food source for salmon, orca whales and other iconic wildlife.

We already know that protecting forage fish works to ensure sustainable fisheries. In the 1990s, regional fisheries managers in Alaska preemptively protected many forage species with the support of the commercial fishing industry. They acted because they understood the importance of these small fish and the local businesses and jobs that depend on them and were concerned about their growing exploitation. Now the Pacific council can extend similar protections along the entire West Coast.
Encourage the council to bring forage fish species under management as soon as possible by submitting an official comment.

Take Action!
Sign this petition to give forage fish the protection they need.


Thursday, September 5, 2013

Seafood Fraud: 59% Of the 'Tuna' Americans Eat Is Not - Tuna!

Nonprofit ocean protection group Oceana took 1,215 samples of fish from across the United States and genetically tested them in order to bring us the following astonishing facts:

• 59% of the fish labeled "tuna" sold at restaurants and grocery stores in the US is not tuna.

 • Sushi restaurants were far more likely to mislabel their fish than grocery stores or other restaurants.

• In Chicago, Austin, New York, and Washington DC, every single sushi restaurant sampled sold mislabeled tuna.

 • 84% of fish samples labeled "white tuna" were actually escolar, a fish that can cause prolonged, uncontrollable, oily anal leakage.

• The only fish more likely to be misrepresented than tuna was snapper, which was mislabeled 87% of the time, and was in actuality any of six different species.

If you've ever wondered why the sushi in the display case is so affordable, given the dire state of the world's tuna supply, well, now you know.


Wednesday, September 4, 2013

Alive - Or Just Un-Dead? Deep Microbes Live Long and Slow

Scientists from the Integrated Ocean Drilling Program have announced the findings at the Goldschmidt conference, a meeting of more than 4,000 geochemists, in Florence, Italy.

Fumio Inagaki of the Japan Agency for Marine-Earth Science and Technology, reported that the microbes exist in very low concentrations, of around 1,000 microbes in every tea spoon full of rock, compared with billions or trillions of bacteria that would typically be found in the same amount of soil at Earth's surface.

Alongside the simple single-celled organisms (prokaryotes) found in the deep rocks, Tim Engelhardt of the University of Oldenburg, Germany, showed that viruses are even more abundant, outnumbering microbes by more than 10 to one, with that ratio increasing with depth.

Speaking to BBC News, Dr Engelhardt said of these viruses: "They are quite stable in these sediments, especially as the metabolic rates of the cells are so low, and they exist in sediments up to 100 million years old."

The number of microbes was so low that the distances between them were much greater than those of communities at Earth's surface, so the scientists were surprised to find that they could support a virus' life cycle.

"We're pushing the boundaries of what we understand about how viruses cycle on Earth elsewhere, by studying them in the deep biosphere" Dr Beth Orcutt of Bigelow Laboratory for Ocean Sciences in Maine, US, told BBC News.

Cores Microbes exist in sediments that are up to 100 million years old

Dr Orcutt continued: "One of the biggest mysteries of life below the sea floor is that although there are microbes down there it's really hard to understand how they have enough energy to live and how incredibly slowly they are growing.

"The deeper we look, the deeper we are still finding cells, and the discussion now is where is the limit? Is it going to be depth, is it going to be temperature? Where is the limit from there being life to there being no life?"
Alive, or just un-dead?
The long-lived bacteria metabolise at such a slow rate that some even question whether this constitutes life at all.

"The other question we have is that even though we are finding cells, is it really true to call it alive when it's doubling every thousands of years? It's almost like a zombie state," Dr Orcutt commented.

Despite being very slow-living and slow-acting, Earth scientists have also suggested that the existence of microbial communities deep in Earth's rocks could be changing the chemistry of the rocks, the deeper Earth, and the planet itself.

By locking up and using carbon within the rocks, these deep organisms could be modifying the carbon cycle on Earth, and could ultimately have some impact on the rates of release of carbon dioxide into the atmosphere from volcanoes over Earth's history.

[Source]: Simon Redfern