ANN ARBOR — Scientists have known for nearly a century that cold-blooded animals, such as worms, flies and fish all live longer in cold environments, but have not known exactly why.
Researchers at the University of Michigan Life Sciences Institute have identified a genetic program that promotes longevity of roundworms in cold environments—and this genetic program also exists in warm-blooded animals, including humans. (more…)
Japan fisheries data provides a look at how the ocean is faring 18 months after the worst accidental release of radiation to the ocean in history
Japan’s “triple disaster,” as it has become known, began on March 11, 2011, and remains unprecedented in its scope and complexity. To understand the lingering effects and potential public health implications of that chain of events, scientists are turning to a diverse and widespread sentinel in the world’s ocean: fish.
Events on March 11 began with a magnitude 9.0 earthquake, the fourth largest ever recorded. The earthquake in turn spawned a massive 40-foot tsunami that inundated the northeast Japanese coast and resulted in an estimated 20,000 missing or dead. Finally, the wave caused catastrophic damage to the Fukushima Dai-ichi nuclear power plant, resulting in the largest accidental release of radiation to the ocean in history, 80 percent of which ended up in the Northwest Pacific Ocean. (more…)
Ear-bone ‘tree rings’ provide evidence of connectivity
Ocean scientists have long known that juvenile coral reef fishes use coastal seagrass and mangrove habitats as nurseries, later moving as adults onto coral reefs. But the fishes’ movements, and the connections between different tropical habitats, are much more complex than previously realized, according to a study published September 3 in Proceedings of the National Academy of Sciences. The findings have important implications for management and protection of coral reefs and other marine environments.
A number of studies have demonstrated a strong relationship between the presence of coastal wetlands and offshore fish abundance and fisheries yield, but it has proved difficult to develop quantitative assessment of habitat use by fish or their movement among different habitats. “The rationale for this study,”says Simon Thorrold, a biologist at Woods Hole Oceanographic Institution (WHOI), “was to determine the relative importance of different nursery habitats to reef fishes that spend their adult lives on coral reefs but may spend at least part of their juvenile residency elsewhere.” (more…)
Answer may be ‘adaptive zones’ that limit species number, life scientists report
There are more than 400,000 species of beetles and only two species of the tuatara, a reptile cousin of snakes and lizards that lives in New Zealand. Crocodiles and alligators, while nearly 250 million years old, have diversified into only 23 species. Why evolution has produced “winners” — including mammals and many species of birds and fish — and “losers” is a major question in evolutionary biology.
Scientists have often posited that because some animal and plant lineages are much older than others, they have had more time to produce new species (the dearth of crocodiles notwithstanding). This idea — that time is an important predictor of species number — underlies many theoretical models used by biologists. However, it fails to explain species numbers across all multi-cellular life on the planet, a team of life scientists reports Aug. 28 in the online journal PLoS Biology, a publication of the Public Library of Science. (more…)
Environmental change is the selective force that preserves adaptive traits in organisms and is a primary driver of evolution. However, it is less well known that evolutionary change in organisms also trigger fundamental changes in the environment.
Yale University researchers found a prime example of this evolutionary feedback loop in a few lakes in Connecticut, where dams built 300 years ago in Colonial times trapped a fish called the alewife.
In a study published May 23 in the journal Proceedings of the Royal Academy B, the Yale team describes how this event fundamentally changed the structure of the alewife and, with it, the water flea that the alewife feeds upon and the food chain that supports them both. (more…)
Ocean currents may mitigate warming near handful of equatorial islands
Scientists predict ocean temperatures will rise in the equatorial Pacific by the end of the century, wreaking havoc on coral reef ecosystems.
But a new study shows that climate change could cause ocean currents to operate in a way that mitigates warming near a handful of islands right on the equator.
Those islands include some of the 33 coral atolls that form the nation of Kiribati. This low-lying country is at risk from sea-level rise caused by global warming. (more…)
*The recent returns of Atlantic salmon in the Thames are more likely to be a result of fish straying from nearby rivers rather than a consequence of expensive restocking efforts, according to new research by the University of Exeter.*
A team of University of Exeter bio-scientists, in collaboration with the Environment Agency, Westcountry Rivers Trust and Oviedo University, Spain, have been collecting genetic data from returning fish, which suggests that habitat restoration was more effective than re-introductions. The findings will be published in the journal ‘Biological Conservation’.
Lessons from the study could be applied to other rivers across the UK according to the co-author of the paper Dr Jamie Stevens, Associate Professor of Molecular Systematics at the University of Exeter. Dr Stevens says: “Traditionally, people – such as river owners and anglers – have wanted big fish swimming up their rivers. The easiest way to ensure this quickly has been to restock those rivers with exogenous fish (from outside the river system).” (more…)
*Extinction of fishes 360 million years ago created natural ecology experiment*
In present-day ecology, the removal or addition of a predator in an ecosystem can produce dramatic changes in the population of prey species. For the first time, scientists have observed the same dynamics in the fossil record, thanks to a mass extinction that decimated ocean life 360 million years ago.
What was bad for fish was good for the fish’s food, according to a paper published online in Proceedings of the National Academy of Sciences. Researchers from the University of Chicago, West Virginia University and The Ohio State University found that the mass extinction known as the Hangenberg event produced a “natural experiment” in the fossil record, with results that mirror modern observations about predator-prey relationships. (more…)
