Delving Into the Past to Predict the Future

ISSUE #27 II MARCH-APRIL 2007 DE LVING IN TO THE PAST TO PRED ICT THE FUT URE AN ARCT IC RESE ARC HER YIE LDS A TREAS URE TROVE OF CLIMATE CHANGE INFORMATION FROM THE BOTTOM OF LAKES. By Ryan Stuart PROJECT When Arctic researcher Marianne Douglas [1] looks at a lake, she does n't just think abo ut taking a dip or getting a drink. She wo nde rs what clues to the past are hidden in its wa tery depths. Specifically, she wonders about diatom s [2]. These min ute organisms ca n be found in almost eve ry pond and lake on earth, and when they die, th ey lea ve behi nd glas s ce ll wall s th at pile up in layers at th e bottom of lakes. Similar to rings in a tree trun k, these layers ho ld a lot of information abo ut past climate. "They're like little jewels under the microscope," Dougla s says. "Each s pec ies has its own ornamentation and occupies its own s pecific niche. As env ironmental conditions cha nged, so did the s pecies. We take core s amples of the lakebeds, a nd as you go down in th e sections, you're going bac k in time. Some of the changes a re abso lute ly dra matic-huge, huge changes." Doug las's pass ion is finding and unravell ing thos e changes us ing a s ci en ce called pa leo limnology [3]. What looks like Arctic pond s cum to the average person is actually a clear timeli ne of ecological cha nge un der Douglas's train ed eye. She us es 20 years of paleolimnological res earch to s how how the Arctic's clima te is changing, to fill in the holes in Arctic climate dat a, and to tes t forward-looking clima te models. Douglas first looked to diatoms as a vehicle to the past in 1986 as a grad s tude nt worki ng with Jo hn Smol [4], a paleolimnologist at Queen 's University. Smol s ent her to Cape Herschel on Elles me re Is la nd, the most nort herly isl and in the Arctic Archi pelago, to collec t samples [5] from s ma ll lakes an d pond s. Bac k in th e lab that fall, Douglas started exam ining th e sediment samples a nd was ast ounde d at what s he found. She had expected th e types of dia toms in the sediment to change s lowly over time as the climate gradually warmed from th e Ice Age to present day. Instead, the s amples s howed that for 4,000 years, on ly three or four speci es of diatoms dominated. Then, surprisingly, the dating samples [6] confirmed that after abo ut 1850, diat om divers ity jumped to more than 100 additional s pecies. , , "It would be like going to sleep having only three or four neighbours and the n waking up in a new s ubdivision," Douglas s ays. "In biolog ical terms, it wa s a dr asti c cha nge." Using ice core data [7], Douglas concluded that the pos t-1 850 changes were caused by decreased volcanic activi ty and increased solar acti v ity. This, along with possible early effects of human-infl uenced warming, caused the temperature to ris e. That meant the Arctic lake ice me lte d earlier in the year th an usual, providing a longe r growing season for aquatic mos ses and the like . That in turn cre ate d new nich es for differ e nt types of diatoms to develop . 'What we're seeing is th e tippi ng point," s he sa ys . "The ecological th reshold was reached," Before 1850, the liv ing conditions in th e lakes we re s o extre me that on ly a few s pec ies could thr ive. Around 1850, the environme nta l conditions in the lake change d and, suddenly, dozen s of species cou ld thrive. Further study revealed another marked increase in life in the 1920s, which coincided with increased carbon dioxide readings in ice cores ca used by th e burning of fossi l fue ls . It prom pted Douglas , in 1994, to publis h one of the ea rly sc ientific pape rs s howing th e effec ts of globa l warming in th e Arctic. "Her finding s were very controvers ia l at the time," Smol says. Not so today. Most scientists now believe in globa l warm ing- in fact, physicists and climatologist s us e Doug las's findings to predict how the weather will change in the future. Predictions are made with global clim at e model s [8] generated by powerful computers that forecas t future land surface temperatures, sea ice, ocean currents, and more. Historical dat a is then us ed to test the mode l's accuracy. Richa rd Peltier [9] , an astronomic physi cist at the University of Toronto. is one of many s cientists relying on Dougla s's res earch. He uses her results to confirm his mod els' predictions about whe re clim at e change will be most extre me , a nd what eco logical cha nges will result. "Our models show that globa l climate change s hould be most inte nse in high nor thern latit udes," says Peltier. 'We also expect to see changes in freshwater lake ecology. Marianne and John's research results are very useful at con firming th is ," The th eory goes like this : if th e models can acc ura te ly predict past clima te conditions , given previous atmospheric ca rbon levels, th en th ey'll prob ably do a good job of predicting future conditions , given future carbon project ions. Therefore, it is through Douglas's exa minat ion of the past that sc ientists like Pe ltier can prepare for the futu re . [1] Dr. Mar ianne Douglas Professor, Earth and Atmospheric Sciences, University of Alberta Director, Canadian Circumpolar Institute, University of Alberta Founder and former professor, Paleoen vironmental Assessment Laboratory Department of Geology, University of Toronto Former Tier 1 Canada Research Chair in Global Change Dr, Maria nne Douglas says you either love the Arctic or hate it. "I was bitten by the Arctic bug on my first trip:' she says, She's been back almost every summer since to collect samp les from lakes and ponds throughout the Arctic Archipelago, The data she collecte d have appeared in many scientific journ als and won her praise from her col leagues along with a Canada Research Chair in Global Change, But the Arctic is more to her than just a giant Petri dish, .. , keep going back to Cape Herschel: ' she says. "It's a special place, It grounds me:' She plans to return to Cape Herschel in 2007 to continue to record how the climate is changing. "I've witnessed an incredible amount of change: ' she says, "It typifies what is happening in the Arcti c: ' Douglas received her BSc in 1985, MSc in 1989, and PhD in 1994. all from the Queen's University Biology Depart ment, © 14. Douglas , I, I • inno~~~RDA .cA (2) Diatoms Di atoms a re th e most com mon type of algae-a micros copi c uni cel lular orga nism with ce ll walls mad e of s ilica. Scientists believe th ere may be 100.000 types of diat om s found in fresh a nd s alt wat er as we ll as in moist so il and damp s urfaces.In th e marine e nvironment, th ey are cons ide red one of th e most important food so urces. Diatom s are a lso a va lua ble tool for researching clima te cha nge becau s e their glass ce ll wall s pres erve well , and their abunda nce makes sam pling easy. Being ecologically sens itive and able to reprodu ce rapi dly, th ey a re quick to adapt to cha nges. (3) Pa le olimno logy The stud y of inland fresh- and saltwa te r bodies is known as pa leolimnology. This dis ciplin e includes studying sediment cores from lake botto ms as well as th e properties of th e wa ter itself. [4] Dr. John Smol Professor, Paleoecological Environmental Assessment and Research Lab Department of Biology, Queen's University Canada Research Chair in Environmental Change Co-Editor-in-Chief,Journal ofPaleolimnology Editor-in-Chief, Environmental Reviews "Paleolimnology," says Dr. John Smol, "is lik e a history book. It's a record of what the wor ld was lik e in the past, and we can interpret it." Smol is one of the first Arcti c paleoli m noloqists, having travell ed to the Arctic in 1983 and returned many times since. Before he went to the Arcti c. Smol worked on ident ifying the effects of acid rain in the 1980s. Today, he continues to study lakes and their sediment history throughout the world. He regularly publi shes papersandbooksonhisstudies andcontinuesto bea leadingresearcher in paleoli mnology. Smol was the 2004 winner of Ca nada's biggest scientific research prize, the Herzberg Award, worth $1,000,000 over five years. He received his BSc in marine biology from McGill University 119771. his MSc in limnology from Brock University (19791. and his PhD from Queen's University 119821.

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