The decline in sea ice seen in the Arctic in recent decades has been linked by scientists to the spread of a deadly virus in marine (海洋的) mammals. Researchers found that Phocine distemper virus (PDV) had spread from animals in the North Atlantic to populations in the North Pacific.

According to the Intergovernmental Panel on Climate Change, the ice has been retreating by around 12% per decade between 1979 and 2018. These sea ice changes in September (2018) are likely unprecedented (前所未有的) for at least 1, 000 years. “Between 1979 and 2018, the real proportion (比例) of multi-year ice that is at least five years old has declined by approximately 90%,” the IPCC said in their report on the oceans and the cryosphere (冰冻圈) published in September.

Against this changing background, researchers have investigated the likely spread of the PDV infection, which caused a large number of deaths among harbour seals in the North Atlantic in 2002. Melting sea ice is now connecting marine mammals, like these Steller sea lions, which were formerly separated by ice . “As animals move and come in contact with other species, they carry opportunities to introduce and catch new infectious disease, with potentially destructive effects.” said author Dr Tracey Goldstein, from the University of California, Davis.

The authors warn that this trend could continue as they believe climate driven changes in the Arctic ocean will increase. The opportunities for the spread of PDV will likely grow, with uncertain health outcomes for many species.

For people, many other animals, family matters. Consider how many jobs go to relatives. Or how an ant will cruelly attack intruder (入侵的) ants but rescue injured, closely related nest-mates. There are good evolutionary reasons to aid relatives, after all. Now, it seems, family feelings may stir in plants as well.

A Canadian biologist planted the seed of the idea more than a decade ago, but many plant biologists regarded it as heretical-plants lack the nervous systems that enable animals to recognize kin (家族), so how can they know their relatives? But with a series of recent findings, the belief that plants really do care for their most genetically close peers-in a quiet, planty way-is taking root. Some species control how far their roots spread, others change how many flowers they produce, and a few tilt (倾斜) or shift their leaves to minimize shading of neighboring plants, favoring related individuals.

“We need to recognize that plants not only sense whether it’s light or dark or if they’ve been touched, but also whom they are interacting with,” says Susan Dudley, a plant evolutionary ecologist, whose early plant kin recognition studies sparked the interest of many scientists.

Beyond broadening views of plant behavior, the new work may have a practical side. In September 2018, a team in China reported that rice planted with kin grows better, a finding that suggested family ties can be used to improve crop yields. “It seems anytime anyone looks for it, they find a kin effect,” says Andre Kessler, a chemical ecologist at Cornell University.

Bacteria and fungi (真菌) might call to mind the images of diseases and spoiled food, but they also do a lot of good. The billions of microbes (微生物) in a handful of dead leaves, for example, act as nature’s recyclers and regenerate nutrients needed for the next generation of plants to grow.

“If it weren’t for bacteria and fungi, we’d be surrounded by masses of dead trees and plant matter. So they actually do a really important job.” said Sydney Glassman, an assistant professor of the University of California, Riverside.

While microbial communities are the engines driving the breakdown of dead plants and animals, little is known about whether they are equipped to handle big changes in climate. In a paper published in Proceedings of the National Academy of Sciences of the United States of America, Glassman and his colleagues examined what happens after microbial communities move into new climate conditions. The study is a first step toward understanding the vulnerability of these ecosystems to climate change.

To mimic (模仿) a warming planet, the researchers chose five study sites that differ in climate along the San Jacinto Mountains, three of which are in natural reserves operated by the University of California. “While we know that climate influences how fast microbes can recycle plant material, we don’t know how important the particular types of microbes are to recycling,” said Jennifer Martiny, co-author of the study.

To move the microbial communities around, the researchers contained the microbes in nylon containers with tiny holes. These “microbial cages” were filled with dead grass and live microbes sourced from each study site.The containers allowed water and nutrients—but not microbes—to move in and out. The amount of grass decayed by the caged microbes was measured at 6, 12, and 18 months.

The study confirmed previous results that sites with moderate climates saw the most rot and therefore were the most effective places for nutrient recycling. Quite surprisingly, however, the source of the microbes also affected the amount of rot. For example, when moved into the drier bushes, grassland-sourced microbes outperformed the bush residents by as much as 40 percent.

“We expected to see a ‘home-field advantage’ situation where every microbial community decomposed (分解) best at its own site, but that wasn’t the case,” Glassman said. “While we know that microbes decompose plants more slowly in hotter and drier environments, we are just now learning that specific microbial communities play an independent role in decomposition, and it is yet to be seen how these communities will be affected by climate change and desertification.”