Alaska's Underground 

 Frontier 



An observatory that looks 

 down — not up — at the planet's 

 microbial diversity 



By Christine M/ot 



The workboat I'm riding whips down the 

 Tanana River in the interior of Alaska, 

 just west of Fairbanks. Rains in the past 

 two weeks have made the Tanana high and swift 

 in its rush to meet the Yukon River, on its way to 

 the Bering Sea. Today is bright, with a ceaseless 

 boreal sun and a breeze that keeps the mosquitoes 

 at bay — a good day for summer fieldwork. 



The boat stops along one of many side channels 

 that make up this labyrinth of a river, and we un- 

 load on a small, thickly wooded island. Our gear 

 is not high-tech: a couple of T-shaped soil corers, 

 boxes of zippered plastic bags and latex gloves, ajar 

 of ethanol. We hike into the brush and begin. 



Most people come to Alaska for the big things: 

 big mountains, big game, big fish. We have come 

 for the little things. We are here to collect and 

 study the bacteria that live in the cold, thin soil 

 beds. Ecologists have been studying the succes- 

 sion of boreal forest at this site, the Bonanza Creek 

 Experimental Forest [see map on opposite page], 

 since the 1960s. (More recently the National Sci- 

 ence Foundation, or NSF, has been funding the 

 study as part of its Long-Term Ecological Re- 

 search Network, which was established in 1980.) 

 In the past few years the study has gone under- 

 ground, literally, to explore the microbial com- 

 munities on which the forest depends. 



The small island — our first sampling site — is 

 thick with balsam poplar. The trees represent an 

 early stage in the centuries-long successional 

 cycle of the forest. Heather K. Allen, a doctoral 

 student who is writing her dissertation on the 

 bacteria living here, clears the leafy duff and stabs 

 a soil corer through a knot of roots and into the 

 forest floor. Out comes the first of some eighty 

 samples we'll collect today. 



Collecting bacteria in the wild hasn't changed 

 much since the days of the early microbe hunters, 

 such as Louis Pasteur, 150 years ago. Preventing 



Aerial view of the Tanana River, looking roughly south, shows some of its mean- 

 dering course near Fairbanks, Alaska; the peak of Denali is visible on the horizon 

 at the upper right. The braided river regularly creates new islands out of silt that 

 can support forest life, with a little help from microorganisms. 



54 



N A I URAL HISTORY April 2006 



