Field of Science

Zombie Mosses Rise Again

Rising from the depths, mosses that have been frozen in suspended animation for hundreds of year grow again! You may recall that zombie mosses were in the news last summer, well they are back. In this study, published last week in Current Biology, mosses were dug up from an island in Antarctica and regenerated new plants in the laboratory. Digging up and growing mosses is typically not a news-worthy activity. The amazing thing about these mosses is that they had been buried in the permanently frozen ground (permafrost) for the last 1,500 years, since Roman times.

This story was covered by a variety of news sources. By far my favorite was Jennifer Frazier's coverage for National Geographic. She did a great job of discussing the science and soliciting comments from scientists doing similar research. For an audio clip of the story, I enjoyed the 60 second science podcast from Sophie Bushwick at Scientific American. 

Let's put this study in perspective. Mosses can survive freezing. This is a known ability. Mosses are buried beneath the snow during winter in many places across the globe and each spring they thaw and resume growth. This study pushes our knowledge of this phenomenon to the extreme and leads to some questions. 

How long can mosses survive frozen and recover? In the National Geographic article, Dr. LaFarge mentions that they have an upcoming study to test whether 50,000 year old mosses can resume growth. There will most definitely be more to come on this topic.

What are the compounds inside moss cells that act as antifreeze, helping them to prepare for and survive freezing? I know that I have read a paper on this somewhere. My memory says that they are called LEA proteins, but I can't recall which paper discussed them relating to mosses. 

Can all species of mosses survive this long? Thinking ecologically, my guess would be that mosses from the tropics would not be able to survive frozen for even a single winter, let alone hundreds of years. Whereas, thinking systematically, the mosses that grew from 400 years ago (LaFarge et al 2013) were from four different moss families (Aulacomniaceae, Encalyptaceae, Ditrichaceae, Pottiaceae) and the one in this study is from a different family, the Dicranaceae. From this small sample it looks like surviving frozen for extended periods of time is a feature of many groups of mosses. 
Figure S1 from Roads et al. 2014.Chorisodontium aciphyllum moss bank sampled in this study; 
(a) map of Signy Island indicating the study location; (b) coring the moss bank;
(c) surface section of clearly separable gametophytes;

(d) fresh-collected section of core from within the permafrost layer.

This supplemental figure from the paper gives you a peek into some of the research methods. The upper right shows the researchers collecting mosses in the field. The lower right is a freshly collected core of mosses. It is amazing how compact the sample appears. It looks like a solid metal rod, but really the bottom left is a pulled-apart version of the bottom right. 

I am looking forward to the next tale of zombie mosses from LaFarge and colleagues. 
Can 50,000 year old mosses grow again? 

March 2014 Desktop Calendar at Yosemite

I took some time off this week and went camping in Yosemite National Park. It was my first time there and it was an amazing visit. Granite mountains, boulders covered in mosses, and tough trees clinging to cliffs. Yes, I mentioned rocks three times in the same sentence. Geology is everywhere in Yosemite! If I had grown up in the west, I am convinced I would have been a geologist rather than a botanist. The plant to rock ratio is skewed completely in the opposite direction from the eastern deciduous forests that I grew up surrounded by in the midwest. 

The geology of the Sierra Nevada Mountains is an interesting tale. The vast majority of the exposed rock is granite and was formed millions of years ago deep underground from magma. As time passed erosion of the layers above, glaciation, and uplifting exposed the upper layers of these rocks. Giving us literally translated from Spanish the "snowy mountain range" of the Sierra Nevada. 

Unfortunately for the water situation in California there was not much snow in the mountains when we visited last weekend. Just the tops retained a light dusting of snow and the vast majority of the trails were open and dry. If you are in the area I would highly recommend a visit to this lovely park. Just beware, Yosemite is one of the most highly visited national parks in the United States and I hear that the summer crowds can be intense, especially in the valley. 

Overall it was a much needed vacation and a spectacular piece of nature to visit. I was also very impressed by the accessibility of many of the waterfalls and nature trails. A number of them are paved with flat to mild grades. It is great to see a national park making all of its scenic treasures available to a wide audience!

Half Dome in Yosemite National Park

March Desktop Calendar

1 - Single click on the image to open it up in a new window. (If you use the image directly from the blog post you will lose a lot of resolution.)

2 - Right-click (or ctrl-click) on the image, and chose the option that says, "Set as Desktop Background" or "Use as Desktop Picture". The wording may vary.

3 - If the image does not fit your desktop neatly, you may have to adjust the image (Mac: System Preferences - Desktop and Screen Saver - Desktop; Windows: Control Panel - Display - Desktop) and choose "Fill screen" as the display mode of your background image.