ScienceDaily: Earth & Climate News

1. Scientists date prehistoric bacterial invasion still present in today's plant and animal cells
   How long ago did bacteria invade the one-celled ancestors of plants and animals to become energy-producing mitochondria and photosynthesizing chloroplasts? Researchers developed a statistical way to analyze the variation in genes common to mitochondria, chloroplasts and the eukaryotic nucleus to more precisely date these events. They found that the cyanobacterial invasion of plants took place millions of years more recently than thought.
2. New details about H7N9 influenza infections that suddenly appeared in China
   Researchers have revealed new information about the latest strain of type A influenza, known as H7N9.
3. Biological fitness trumps other traits in mating game
   When a new species emerges following adaptive changes to its local environment, the process of choosing a mate can help protect the new species' genetic identity and increase the likelihood of its survival. But of the many observable traits in a potential mate, which particular traits does a female tend to prefer?
4. Less is more: Novel cellulose structure requires fewer enzymes to process biomass to fuel
   Improved methods for breaking down cellulose nanofibers are central to cost-effective biofuel production and the subject of new research. Scientists are investigating the unique properties of crystalline cellulose nanofibers to develop novel chemical pretreatments and designer enzymes for biofuel production from cellulosic -- or non-food -- plant-derived biomass.
5. Environmentally friendly battery made from wood
   Taking inspiration from trees, scientists have developed a battery made from a sliver of wood coated with tin that shows promise for becoming a tiny, long-lasting, efficient and environmentally friendly energy source. The device is 1,000 times thinner than a sheet of paper.
6. The rhythm of the Arctic summer: Diverse activity patterns of birds during the Arctic breeding season
   Our internal circadian clock regulates daily life processes and is synchronized by external cues, the so-called Zeitgebers. The main cue is the light-dark cycle, whose strength is largely reduced in extreme habitats such as in the Arctic during the polar summer. Using a radiotelemetry system biologists have now found, in four bird species in Alaska, different daily activity patterns ranging from strictly rhythmic to completely arrhythmic.
7. Outlook is grim for mammals and birds as human population grows
   The ongoing global growth in the human population will inevitably crowd out mammals and birds and has the potential to threaten hundreds of species with extinction within 40 years, new research shows.
8. City slicker or country bumpkin: City-life changes blackbird personalities
   The origins of a young animal might have a significant impact on its behavior later on in life. Researchers have been able to demonstrate in hand-reared blackbirds that urban-born individuals are less curious and more cautious about new objects than their country counterparts. This study sheds light on an interesting debate on whether personality differences between rural and urban birds are behavioral adjustments to urban environments, or if there is an underlying evolutionary basis to the existence of different personalities in urban habitats.
9. Siberian caves warn of permafrost meltdown
   Climate records captured in Siberian caves suggest 1.5 degrees of warming is enough to trigger thawing of permafrost, according to a new article.
10. Contribution of particulate matter from air pollution to forest decline
    Air pollution is related to forest decline and also appears to attack the protecting wax on tree leaves and needles. Scientists have now discovered a responsible mechanism: particulate matter salt compounds that become deliquescent because of humidity and form a wick-like structure that removes water from leaves and promotes dehydration.