Warming up to a longer lifespan

A warm start in life can make fish better able to cope with high and low temperatures later in life, researchers at the University of St Andrews have discovered. Work carried out by Professor Ian Johnston and Graham Scott of the University suggests that growing up at warmer temperatures might help some aquatic animals cope with the more varied climates expected with climate change.

They found that raising zebrafish embryos at warmer temperatures, improved how well they could adjust to changes in temperature later in life. Such temperature changes mimicked the seasonal variation they would experience in the wild. Zebrafish were selected as a model fish species which is widely used in fundamental biological and biomedical research.

When zebrafish embryos raised in warm water experienced temperature variation as adults, they could swim faster, had muscle better suited for aerobic exercise, and expressed - at higher levels - many of the genes that contribute to exercise performance.

The authors concluded that being exposed to challenging temperatures in early life might help some fish cope with warmer or more variable temperatures when they get older, which could help mitigate the adverse effects of global warming. The research is published in the Proceedings of the National Academy of Sciences and was supported by an EU-FP7 grant ‘Lifecycle’ and the “Marine Alliance for Science and Technology”, a pooling initiative of the Scottish Funding Council.

Professor Johnston said: “This research represents a paradigm shift in our understanding of the thermal biology of aquatic organisms. “It shows how the temperature experienced at the earliest stages of development can have persistent effects on the physiology of adult stages. “In order to predict the likely effects of future climate change these early developmental effects need to be taken in to account. Indeed, for some species warming at the embryo stage may improve the ability of adults to cope with seasonal temperature change.”


Rain softens worst drought in the US

The remnants of Hurricane Isaac that blew through the middle of the US recently softened the worst drought in decades in some areas, but a large portion of the nation remains desiccated with ponds still too shallow to water cattle, fields too dusty for feeding and crops beyond the point of salvage, meteorologists and agriculture experts said Wednesday.

Conditions have, in fact, worsened in some rain-starved regions untouched by the hurricane’s gray clouds, meteorologists said. The worst of the drought has shifted slightly west, to the Central Plains, stretching from the bottom of South Dakota to north Texas.

Thick, swirling, gray bands from Hurricane Isaac drenched broad areas of crop country, from Arkansas through Missouri to Illinois, with two to eight inches of rain. The rain brought much needed moisture to rock-hard soil, a welcome development for farmers planting wheat in the coming weeks. Some pastures have started to green in the region and the pods on some soybean plants have spruced up.

John Eligon
New York Times News Service

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