David W. Schindler—Icon and Iconoclast

On 04 March 2021, the world lost its freshwater colossus—a man who led development of Limnology from an esoteric academic discipline in 1950s to keystone environmental science 50 yr later. His masterful blend natural history, ecosystem experimentation, biogeochemistry, and advocacy fundamentally changed our world. It is unlikely we will see another so profoundly shape understanding inland waters as David William Schindler has done (Fig. 1). Born 03 August 1940, Dave grew up on around lakes western Minnesota where tall grass Prairies meet eastern deciduous forest, near town Barnesville, Minnesota. In fact, it was his love forested landscapes, combined with plain-spoken practicality a prairie kid, that characterized much Dave's life scientific career. Eldest four children, avid reader, outdoorsman, student, athlete (football, wrestling), favoring biology under tutelage high school teacher, Rudolfs Malta. He initially enrolled engineering physics at University 1959, but came mentorship 44-yr-old WWII veteran, Gabriel Comita, had started faculty position North Dakota State 5 earlier needed someone set bomb calorimeter lab sample local during summer. While Comita's lab, read Charles Elton's Ecology Invasions by Animals Plants, Niko Tinbergen's Animal Behaviour, G. Evelyn Hutchinson's then brand-new A Treatise Vol 1: Geography, Physics Chemistry. This trio foretold next move—a Rhode's Scholarship study Oxford, Tinbergen, Elton, whose field-based research appealed more young Ph.D. student. also published undergraduate work Comita Science! Schindler's flow energy lake food webs three profound effects approach research. First, focused mind entire ecosystems—their physics, chemistry, biology. Second, imbued life-long preference for empirical experimental approaches over modeling or theoretical exercises. Third, informal daily discussions other Oxford students (Tinbergen, Richard Dawkins) sharpened analytical skills made him formidable debater. Each these became hallmarks 60-yr career highlights influence mentors student colleagues crafting one's path. marked purposeful if abstruse change, 1966 Trent University, new rural Ontario, Canada, having turned down elite opportunities Yale Michigan. simply preferred boreal landscape. second paper, Nature, use liquid scintillation measure rates photosynthesis. However, become interested nutrient pollution eutrophication, soon enticed join Freshwater Institute (FWI) Winnipeg Jack Vallentyne, head Eutrophication Section Fisheries Research Board Canada (FRBC). Vallentyne himself champion environment public education (latterly “Johnny Biosphere”), received Hutchinson, before taking positions Queen's Cornell universities. Upon joining FRBC, wanted “experimental area,” modeled part whole-lake experiments Wisconsin's Arthur Hasler FWI's Director Wally Johnson. After recruiting some world's best international limnologists (e.g., Vollenweider, Kazimierz Patalas, Mitsuru Sakamoto, et al.), sights Dave, convincing 1968 lead what later ELA, The Experimental Lakes Area. Both were dismayed eutrophication Laurentian Great Lakes, well raging debate about causes. one hand, prior surveys showed clearly phosphorus (P) content strongest predictor algal growth, whereas bottle-scale fertilization experiments, heavily supported soap industry, suggested phytoplankton rapidly limited supply atmospheric CO2 after fertilization. team resolved issue surveying hundreds undisturbed ELA region Kenora, selecting (Lake 227) lowest levels dissolved inorganic carbon, fertilizing equivalent those seen lower Lakes. Within weeks, biomass increased 10-fold, green algae cyanobacteria. contrast, diffusion only limiting short period midday, compensated respired microbes terrestrial organic matter. experiment did not produce surface blooms N2-fixing cyanobacteria polluted waters, altered nitrogen (N) inputs Lake 227 demonstrate diazotrophic species predominated P concentrations low N : ratios. Further conducted shallow lakes, capstone 226 basins narrow hydrologically separated curtain differentially fertilized C, N, 2). resulting bloom C + treatment, basin, captured aerial photograph most iconic images all time. That photo, peerless accompanied it, clear, direct ever-present engagement policy makers, resulted phosphate ban detergents, removal wastewater many cities. These have protected freshwaters extreme degradation half century. Despite successes, smooth sailing ELA. By early 1970s, FRBC disbanded moved eventually Canadian Department Oceans, unit fish-habitat mandate less supportive particularly within charged political arena. Recognizing need adapt, series acidification identify mechanisms which acidic precipitation damaged their webs, emblematic trout. As work, single basin 223) progressing split-basin 302) contrast H2SO4 HNO3. Again, photo emaciated trout, numerous publications key aquatic journals (Canadian Journal Aquatic Sciences, CJFAS; Oceanography) high-profile papers Science, provided essential evidence convince makers urgency reduce industrial air pollution. Even so, may been enough effect change without dogged effective promotion evidence, through tireless presentations, legislative hearings, media interviews, engagements makers. culmination this changes laws (1990 Clean Air Act, 1991 Acid Rain Treaty) continue protect today. 1980s closed, increasing federal government restrictions, employment prospects partner Dr. Suzanne Bayley, herself world-class wetlands scientist, forced do unthinkable—leave 1989, he Bayley accepted professorships Alberta, thereby opening chapter remarkable life. Several strands make time impactful. noted above, farming background immensely practical. When faced obstacles, removed them, whether developing better field methods primary production capture zooplankton (Schindler-Patalas trap) resolving controversy (whole-lake experiments). upbringing directness simplicity communication suited outreach engagement. learned argue full force evidence. Blessed terrific memory deep devotion learning (everyone story reading Nature Science while hunting, fishing, training dogs, etc.), thrived superb encouraged be merciless critiques manuscripts. noted, “if you think your friends' comments are bad, wait until enemies get it.” Critically, never satisfied short-term, singular, superficial analyses support position. Instead, topics addressed multiple sequential often different scales, each refining knowledge comprehensive reached. Usually, findings (JFRB; CJFAS), because prestigious outlet, because, pre-Internet era, JFRB worlds' widely distributed journal. seen. transition back university end involvement 21 monitoring, slowly phenomena such climate biodiversity loss becoming apparent, former pivoted again address now critical issues 3). 30 departure, presence felt throughout notes recent director Michael Paterson. would 20+ long-term ecological program introduced exotic fishes mountain perhaps reflecting lifelong admiration book 4). At same time, expanded activities include ecology northern rivers, protection Boreal Forest ecozone, Alberta tar sands development, deposition mercury, agrochemicals pollutants, Indigenous Treaty rights. instead conducting governmental researchers, ideas incubator generations scholars, whom continued dozens universities agencies. Transition academe challenges. politics, small grants, inaccessible leadership, and, course, teaching operating model. typical fashion, solution stuff liked, way liked bin rest. definition rugged quickly found like-minded people built network allowed conduct whole Banff National Park—a nearly impossible feat case, proved biotic impoverishment century fish stocking could reversed removing non-native replenishing invertebrates fishless lakes. image billions bright red copepods being hauled Rocky Mountains helicopter cannot easily forgotten. engrossed diversity leading role matter, UV radiation, trophic cascades transparent alpine waters. organochlorine contamination snowpacks glaciers high-latitude demonstrated how past left legacy cold regions damage unleashed warming meltwater transport 5). Life family fully embrace passion sled-dog racing, building 90-dog kennel winning championships. One terrifying questions asked seemingly innocuous, “can feed dogs weekend?” Sled-dog racing regularly reconnect land, clearing “big thoughts” elude us. 21st saw increase markedly—a fact barely credible given point. remarked twice (350 date) forgone presentations popular press writings, obligation scientists bring public. Through awards (Stockholm Water Prize; Volvo, Tyler, Rachel Carson awards; major ASLO SIL national academy memberships; Order Canada; 15 honorary doctorates), face world, lending authority credibly challenge regional governments, admonish develop policy, improve beloved forest Still there frustrations. dying 1000 cuts, propagated unending human population growth resource consumption. rise nonpoint source frustrated public, government, failed heed lessons past. recognition importance history work—from older literature paleolimnology, advice students, “talk old people.” merely redoubled efforts syntheses impacts, biodiversity, prairies ecosystems, Ecozone. died surrounded family. end, heart infection got him—medically result broken ribs, metaphorically environment. everything, fought right confident vision, still recognizing enormity done. missed knew him. passionate man, inspirational mentor, quiet introvert, fierce combatant, stubborn farm boy, scientist. Dave. wonders might like joined Hutchinson rather than small, newly formed university. Did lose “next G.E. Hutchinson?” We not. gained first D.W. Schindler—the scientist limnology Peter R. Leavitt, Regina Karen A. Kidd, McMaster Rolf D. Vinebrooke, Marguerite Xenopoulos, behalf postdocs.