Oldest Horseshoe Crab Fossil Found, 445 Million Years Old

Daily Science Journal (Feb. 12, 2008) — Few modern animals are as deserving of the title “living fossil” as the lowly horseshoe crab. Seemingly unchanged since before the Age of Dinosaurs, these venerable sea creatures can now claim a history that reaches back almost half-a billion years.

Lunataspis aurora - fossil paratype specimen (about 25 mm wide) beside the dried carapace of a young modern horseshoe crab. (Credit: Left image courtesy of G. Young, The Manitoba Museum; right, D. Rudkin, Royal Ontario Museum)

In a collaborative research article published recently in the British journal Palaeontology, a team of Canadian scientists revealed rare new horseshoe crab fossils from 445 million year-old Ordovician age rocks in central and northern Manitoba, which are about 100 million years older than any previously known forms.

Palaeontologist Dave Rudkin from the Royal Ontario Museum, with colleagues Dr. Graham Young of The Manitoba Museum (Winnipeg) and Dr. Godfrey Nowlan at the Geological Survey of Canada (Calgary), gave their remarkable new fossils the scientific name Lunataspis aurora, meaning literally “crescent moon shield of the dawn” in reference to their shape, geological age and northerly discovery sites. Although they are more “primitive” in several aspects than other known horseshoe crabs, their resemblance to living forms is unmistakable.

The fossil horseshoe crabs were recovered in the course of fieldwork studies on ancient tropical seashore deposits, providing yet another important link to their modern descendants that are today found along warmer seashores of the eastern United States and the Indian Ocean.

This is particularly significant, explains Rudkin. “Understanding how horseshoe crabs adapted to this ecological niche very early on, and then remained there through thick and thin, can give us insights into how ocean and shoreline ecosystems have developed through deep time.”

Today, marine shorelines worldwide are being threatened by human activity, and although some horseshoe crab populations are endangered, their enviably long record on Earth indicates that they have successfully weathered many previous crises, including the mass extinction that saw the demise of the dinosaurs and many other life forms 65 million years ago.

“We do need to be concerned about horseshoe crabs and many of the other unusual life forms found on marine shores,” said Dr. Young. “Nevertheless, we can also be mildly optimistic that some of these things have demonstrated a toughness that may allow them to survive our abuse of these environments.”

Living horseshoe crabs are extensively studied, especially in the fields of ecology and medical research. The exciting discovery of these unusual early fossil relatives adds a new introductory chapter to their remarkable story.

David Rudkin is Assistant Curator in the Department of Natural History (Palaeobiology) at the Royal Ontario Museum, and holds an appointment to the Department of Geology, University of Toronto, as a Lecturer in palaeontology. Rudkin joined the former Department of Invertebrate Palaeontology at the ROM in 1975 and began working on fossils from the Burgess Shale in British Columbia.

Adapted from materials provided by Royal Ontario Museum.

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Black Sea To Take Years To Recover From Oil Spill

Daily Science Journal (Nov. 29, 2007) — The oil spill that wreaked havoc in the Kerch Strait leading to the Black Sea in early November will take at least 5 to 10 years for the marine environment to recover, says WWF.

According to WWF specialists, the 2000-tonne spill has badly affected the local fishing industry. Fish caught in the Kerch Strait are not safe for consumption.

The spill has also threatened birds. About 11 endangered species inhabit the area around the strait, including the Dalmatian pelican and great black-headed gull, and many more migrating birds will be wintering in this area in the coming months.

Thanks to the efforts of clean-up crews, including WWF staff and members, some birds have been rescued. However, these activities can only help save a very small percentage of the thousands of affected birds. Two dolphins have also been found washed up on shore where clean-up operations are being conducted, but their chances of survival are slim. The Black Sea is home to common and bottlenose dolphins.

“Although it is practically impossible to completely eliminate the damage caused by the large oil spill,” said Igor Chestin, CEO of WWF-Russia, “we believe that to avoid such disasters in the future drastic changes need to be made in the oil transportation system; oil pollution laws need to be enacted.”

To avoid such accidents in the future, WWF and other environmental NGOs are developing recommendations for the Russian government, which include:

• Local volunteers should be trained to respond to oil spills (WWF has already been training clean-up teams on the Russian coast of the Barents Sea for several years).

• Oil export via the river-sea corridor should be stopped, and river vessels not suited for marine conditions should be instructed to enter ports.

• Russia should develop a legislative base for oil spills, similar to the US Oil Pollution Act adopted after the Exxon Valdez oil spill in 1989, and should set up an independent agency responsible for environmental protection.

According to Alexey Knizhnikov, head of WWF-Russia’s oil and gas project, there is a prepared draft law introducing the “polluter pays” principle and environmental insurance. However, they have not been approved by the State Duma (Russia’s lower house of parliament).

“If these draft law is approved, many problems will be solved, as companies will feel more responsible for the risks they take,” says Knizhnikov.

“We hope that this accident will spur the process in adopting these laws and creating such an agency.”

Adapted from materials provided by World Wildlife Fund.

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Omega-3 Fatty Acids: A Way To Improve Heart Health, Eating Oily Fish May Reduce Inflammation

Daily Science Journal (Aug. 13, 2007) — While a heart-healthy diet has become synonymous with plenty of fruits and vegetables and little fat and cholesterol, there’s more to the story. Omega-3 fatty acids should be part of a heart-healthy diet, too, according to the August issue of Mayo Clinic Health Letter.

Omega-3 fatty acids are a form of polyunsaturated fat important to overall health. As it pertains to heart disease, their main benefit is their ability to reduce the risk of heart rhythm problems in certain groups of people, thus reducing the risk of sudden cardiac death. In addition, omega-3s may help reduce triglycerides, lower blood pressure slightly and reduce blood clotting.

The best source of omega-3s is fatty, cold water fish such as herring, mackerel, salmon and tuna. Plant oils, such as canola and flaxseed oils, also are sources of omega-3s.

For heart disease prevention, near-maximum benefit comes from eating two 3-ounce servings of cold water fish a week. More than that doesn’t appear to offer any additional preventive benefit.

Higher amounts of two kinds of omega-3, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), may benefit some people with established heart disease or high triglyceride levels and can have an anti-inflammatory effect for people with rheumatoid arthritis. In addition, DHA is being studied to see if it can slow the progression of Alzheimer’s disease.

For those who don’t eat fish, a fish oil supplement or an algae supplement can provide omega-3 fatty acids. However, supplements aren’t cheap, and the amount of DHA and EPA in supplements varies widely. Except for people who have established heart disease, the evidence of heart disease prevention is stronger when one eats fish instead of taking supplements. Supplements can pose risks, too. Taking more than 3 grams of fish oil a day may increase the risk of bleeding, worsen heart rhythm problems in those who have arrhythmias or cause other side effects.

Adapted from materials provided by Mayo Clinic, via Newswise.

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Eating Oily Fish May Reduce Inflammation

A new study explains how a diet high in oily fish like salmon and mackerel improves inflammatory conditions, particularly in combination with low doses of aspirin. In a study in the March 7 issue of The Journal of Experimental Medicine, Arita and colleagues identify an anti-inflammatory lipid in humans that is derived from an essential fatty acid in fish oil.

Sockey Salmon. (Photo courtesy of Washington State Department of Fish and Wildlife)

Fatty fish contain large amounts of omega-3 fatty acids--diet-derived essential fatty acids known to benefit patients with cardiovascular disease and arthritis. This research group recently identified a new class of aspirin-triggered bioactive lipids, called resolvins, the activity of which may in part explain the beneficial effects of omega-3 fatty acids. Resolvins are made from the omega-3 fatty acids by cellular enzymes and can reduce inflammation in mice. The main bioactive component of this class of lipids was identified in mice and named resolvin E1.

The researchers have now identified this lipid in plasma taken from volunteers given omega-3 fatty acids and aspirin. Human resolvin E1, the authors show, inhibits both the migration of inflammatory cells to sites of inflammation and the turning on of other inflammatory cells.

This study also reveals a potential pitfall of COX-2 inhibitors, drugs designed to block inflammation, which have been shown to have negative cardiovascular side effects. COX-2 is involved in making resolvin E1 and the authors suggest that inhibition of vascular COX-2 by these inhibitors might block the synthesis of resolvin E1, which would eliminate an important anti-inflammatory pathway. The experiment to prove this idea, however, has yet to be done.

Adapted from materials provided by Journal Of Experimental Medicine.

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Oil Spill Clean-up Agents Threaten Coral Reefs

Daily Science Journal (Jul. 31, 2007) — In a setback for efforts to protect endangered coral reefs from oil spills, researchers in Israel report that oil dispersants -- the best tool for treating oil spills in tropical areas --are significantly more toxic to coral than the oil they are used to clean up. Their study, which urges caution in the use of these materials, is scheduled for the August 1 issue of ACS' Environmental Science & Technology.

Oil-spill clean-up agents are a threat to coral reefs, researchers say. Credit: (Credit: Courtesy of Shai Shafir, The Hebrew University of Jerusalem)

Called the 'rainforests of the sea,' coral reefs are an endangered ecosystem and are disappearing at an alarming rate due to numerous threats, including over-fishing, global warming and pollution, particularly oil spills. Besides hosting a rich diversity of marine organisms, these habitats are also potential sources of life-saving medicines and food for humans. Scientists looking for better ways to protect this important habitat have recently focused on the environmental impact of oil dispersants, detergents used break down oil spills into smaller, less harmful droplets.

In the new report, Shai Shafir and colleagues evaluated the effects of both crude oil and six commercial oil dispersants under laboratory conditions on the growth and survival of two important species of reef corals. The dispersants and dispersed oil droplets were significantly more toxic to the coral than the crude oil itself, the scientists report. The dispersants caused "significant harm," including rapid, widespread death and delay in growth rates, to the coral colonies tested even at doses recommended by the manufacturers, they add.

"Decision-making authorities should carefully consider these results when evaluating possible use of oil dispersants as a mitigation tool against oil pollution near coral reef areas," the report said.

Article: "Short and Long Term Toxicity of Crude Oil and Oil Dispersants to Two Representative Coral Species"

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

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