Cooperative Institute for Research in Environmental Sciences

William M. Lewis Jr.

William M. Lewis Jr.

Aquatic ecosystems, tropical fresh waters, biogeochemistry of inland waters, nutrient cycling, aquatic food chains.


Current Research

Nitrogen takes a detour along the South Platte In aquatic environments, ammonia (NH3) released from organic nitrogen (total oxidized nitrogen, TON) by microbes is oxidized to nitrate (NO3-) by the nitrification process of other microbes in the presence of oxygen through a series of steps involving nitrite (NO2-) as an intermediate (see figure). The result is an increase of nitrate and a decrease in ammonia and TON in the environment. In addition, nitrate, when entering aquatic sediments where oxygen is absent, is converted by microbes through the process of denitrification to N2 gas, an inert end product that corresponds to elimination of nitrogen pollution from the aquatic environment. These processes occur at very high rates in the South Platte River, which, like many other rivers that lie within the drainage of large population centers, receives substantial amounts of ammonia and nitrate from treated wastewater and agricultural practices. The two processes can be quantified based on mass balance of the input and output components for reactions as shown in figure. Validity of mass balance calculations for nitrification and denitrification processes can be checked independently by calculation of mass balance for oxygen. The nitrification process, which produces NO3- as an end product, uses a predictable amount of oxygen. Thus, the oxygen mass balance, which incorporates all processes affecting dissolved oxygen, incorporates a prediction of ammonia loss caused by nitrification. Large inconsistencies between the computed oxygen loss caused by nitrification and the observed oxygen loss from the South Platte River indicates that another process is causing loss of ammonia. Assimilation of ammonia by algae is too small to account for this large difference, so the mass balance points to anaerobic ammonium oxidation (ANAMMOX), a process that is known to occur in aquatic environments but has never been quantified as a major factor in nitrogen mass balance for rivers. An estimation of the rates based on mass balance of oxygen and nitrogen components of the relevant processes suggests that ANAMMOX accounts for 50 percent of ammonia loss in the South Platte River below Denver. This information on the South Platte suggests that ecologists have not given sufficient attention to the importance of ANAMMOX, which is hidden within the related chemical transformations associated with the long-recognized processes of nitrification and denitrification in aquatic systems, and particularly those that carry large pollutant loads.


Summary of nitrogen fluxes relevant to concentrations of ammonia (NH3) and nitrite (NO3-), important pollutants in the South Platte River below Denver.


  • Past President, American Society of Limnology and Oceanography
  • Member of the National Research Council's Water Science and Technology Board, 1993-1999
  • Recipient of the Naumann-Thienemann Medal of the International Society of Pure and Applied Limnology, 1999
  • Sustained Achievement Award of the Renewable Natural Resources Foundation, 1996
  • Chair, National Research Council Committee on Endangered and Threatened Fishes in the Klamath River Basin (2001-2003).

View Publications

  • Rhoades, CC, JH McCutchan, LA Cooper, D Clow, TM Detmer, JS Briggs, JD Stednick, TT Veblen, RM Ertz, GE Likens and WM Lewis (2013), Biogeochemistry of beetle-killed forests: Explaining a weak nitrate response. Proc. Natl. Acad. Sci. USA Version: 1 110 (5) 1756-1760, issn: 0027-8424, ids: 084RZ, doi: 10.1073/pnas.1221029110, PubMed ID: 23319612
  • Robertson, DS, WM Lewis, PM Sheehan and OB Toon (2013), K-Pg extinction patterns in marine and freshwater environments: The impact winter model. J. Geophys. Res.-Biogeosci. Version: 1 118 (3) 1006-1014, issn: 2169-8953, ids: 233EV, doi: 10.1002/jgrg.20086
  • Robertson, DS, WM Lewis, PM Sheehan and OB Toon (2013), K-Pg extinction: Reevaluation of the heat-fire hypothesis. J. Geophys. Res.-Biogeosci. Version: 1 118 (1) 329-336, issn: 0148-0227, ids: 129MN, doi: 10.1002/jgrg.20018
  • Anthony, JL and WM Lewis (2012), Low boundary layer response and temperature dependence of nitrogen and phosphorus releases from oxic sediments of an oligotrophic lake. Aquat. Sci. Version: 1 74 (3) 611-617, issn: 1015-1621, ids: 964XR, doi: 10.1007/s00027-012-0255-6
  • Lewis, WM (2011), Global primary production of lakes: 19th Baldi Memorial Lecture. Inland Waters Version: 1 1 (1) 1-28, issn: 2044-2041, ids: 991RY, doi: 10.5268/IW-1.1.384
  • Clow, DW, C Rhoades, J Briggs, M Caldwell and WM Lewis (2011), Responses of soil and water chemistry to mountain pine beetle induced tree mortality in Grand County, Colorado, USA. Appl. Geochem. Version: 1 26 S174-S178, issn: 0883-2927, ids: 858HZ, doi: 10.1016/j.apgeochem.2011.03.096
  • Segura, C, JH McCutchan, WM Lewis and J Pitlick (2011), The influence of channel bed disturbance on algal biomass in a Colorado mountain stream. Ecohydrology Version: 1 4 (3) 411-421, issn: 1936-0584, ids: 776HF, doi: 10.1002/eco.142
  • Lewis, WM, WA Wurtsbaugh and HW Paerl (2011), Rationale for Control of Anthropogenic Nitrogen and Phosphorus to Reduce Eutrophication of Inland Waters. Environ. Sci. Technol. Version: 1 45 (24) 10300-10305, issn: 0013-936X, ids: 862TZ, doi: 10.1021/es202401p, PubMed ID: 22070635
  • Lewis, WM and JH McCutchan (2010), Ecological responses to nutrients in streams and rivers of the Colorado mountains and foothills. Freshw. Biol. Version: 1 55 (9) 1973-1983, issn: 0046-5070, ids: 639TL, doi: 10.1111/j.1365-2427.2010.02431.x
  • Higgins, TM, JH McCutchan and WM Lewis (2008), Nitrogen ebullition in a Colorado plains river. Biogeochemistry Version: 1 89 (3) 367-377, issn: 0168-2563, ids: 338RV, doi: 10.1007/s10533-008-9225-4
  • Lewis, WM, JF Saunders and JH McCutchan (2008), Application of a nutrient-saturation concept to the control of algal growth in lakes. Lake Reserv. Manag. Version: 1 24 (1) 41-46, issn: 1040-2381, ids: 492NQ
  • Gardner, EM, DM McKnight, WM Lewis and MP Miller (2008), Effects of nutrient enrichment on phytoplankton in an alpine lake, Colorado, USA. Arct. Antarct. Alp. Res. Version: 1 40 (1) 55-64, issn: 1523-0430, ids: 258LI, doi: 10.1657/1523-0430(07-002)[GARDNER]2.0.CO;2
  • Cronin, G, JH McCutchan, J Pitlick and WM Lewis (2007), Use of Shields stress to reconstruct and forecast changes in river metabolism. Freshw. Biol. Version: 1 52 (8) 1587-1601, issn: 0046-5070, ids: 188FW, doi: 10.1111/j.1365-2427.2007.01790.x
  • McGrath, CC and WM Lewis (2007), Competition and predation as mechanisms for displacement of greenback cutthroat trout by brook trout. Trans. Am. Fish. Soc. Version: 1 136 (5) 1381-1392, issn: Feb-87, ids: 220VE, doi: 10.1577/T07-017.1
  • Rodriguez, MA, KO Winemiller, WM Lewis and DCT Baechle (2007), The freshwater habitats, fishes, and fisheries of the Orinoco River basin. Aquat. Ecosyst. Health Manag. Version: 1 10 (2) 140-152, issn: 1463-4988, ids: 187SY, doi: 10.1080/14634980701350686
  • Kaushal, SS, WM Lewis and JH McCutchan (2006), Land use change and nitrogen enrichment of a Rocky Mountain watershed. Ecol. Appl. Version: 1 16 (1) 299-312, issn: 1051-0761, ids: 028SW, doi: 10.1890/05-0134, PubMed ID: 16705981
  • McCutchan, JH and WM Lewis (2006), Groundwater flux and open-channel estimation of stream metabolism: response to Hall and Tank. Limnol. Oceanogr. Meth. Version: 1 4 213-215, ids: 079XO
  • Cronin, G, WM Lewis and MA Schiehser (2006), Influence of freshwater macrophytes on the littoral ecosystem structure and function of a young Colorado reservoir. Aquat. Bot. Version: 1 85 (1) 37-43, issn: 0304-3770, ids: 042HE, doi: 10.1016/j.aquabot.2006.01.011
  • Pribyl, AL, JH McCutchan, WM Lewis and JF Saunders (2005), Whole-system estimation of denitrification in a plains river: a comparison of two methods. Biogeochemistry Version: 1 73 (3) 439-455, issn: 0168-2563, ids: 963QA, doi: 10.1007/s10533-004-0565-4
  • Kaushal, SS and WM Lewis (2005), Fate and transport of organic nitrogen in minimally disturbed montane streams of Colorado, USA. Biogeochemistry Version: 1 74 (3) 303-321, issn: 0168-2563, ids: 978YO, doi: 10.1007/s10533-004-4723-5
  • Ortiz-Zayas, JR, WM Lewis, JF Saunders, JH McCutchan and FN Scatena (2005), Metabolism of a tropical rainforest stream. J. N. Am. Benthol. Soc. Version: 1 24 (4) 769-783, issn: 0887-3593, ids: 991UJ, doi: 10.1899/03-094.1
  • Saunders, JF, M Murphy, M Clark and ML Lewis (2004), The influence of climate variation on the estimation of low flows used to protect water quality: A nationwide assessment. J. Am. Water Resour. Assoc. Version: 1 40 (5) 1339-1349, issn: 1093-474X, ids: 865SA, doi: 10.1111/j.1752-1688.2004.tb01590.x
  • Saunders, JF and WM Lewis (2003), Implications of climatic variability for regulatory low flows in the South Platte River basin, Colorado. J. Am. Water Resour. Assoc. Version: 1 39 (1) 33-45, issn: 1093-474X, ids: 656PY, doi: 10.1111/j.1752-1688.2003.tb01559.x
  • Kaushal, SS and WM Lewis (2003), Patterns in the chemical fractionation of organic nitrogen in Rocky Mountain streams. Ecosystems Version: 1 6 (5) 483-492, issn: 1432-9840, ids: 720HU, doi: 10.1007/s10021-003-0175-3
  • McCutchan, JH, WM Lewis, C Kendall and CC McGrath (2003), Variation in trophic shift for stable isotope ratios of carbon, nitrogen, and sulfur. Oikos Version: 1 102 (2) 378-390, issn: 0030-1299, ids: 704CA, doi: 10.1034/j.1600-0706.2003.12098.x
  • Niyogi, DK, WM Lewis and DM McKnight (2003), Direct and indirect effects of mine drainage on bacterial processes in mountain streams. J. N. Am. Benthol. Soc. Version: 1 22 (2) 276-291, issn: 0887-3593, ids: 691FF, doi: 10.2307/1467998
  • McCutchan, JH, JF Saunders, AL Pribyl and WM Lewis (2003), Open-channel estimation of denitrification. Limnol. Oceanogr. Meth. Version: 1 1 74-81, ids: V42MW
  • McCutchan, JH and WM Lewis (2002), Relative importance of carbon sources for macroinvertebrates in a Rocky Mountain stream. Limnol. Oceanogr. Version: 1 47 (3) 742-752, issn: 0024-3590, ids: 551HP
  • Lewis, WM (2002), Yield of nitrogen from minimally disturbed watersheds of the United States. Biogeochemistry Version: 1 57 (1) 375-385, issn: 0168-2563, ids: 559AG, doi: 10.1023/A:1015709128245
  • Niyogi, DK, DM McKnight and WM Lewis (2002), Fungal communities and biomass in mountain streams affected by mine drainage. Arch. Hydrobiol. Version: 1 155 (2) 255-271, issn: Mar-36, ids: 603BN
  • Niyogi, DK, WM Lewis and DM McKnight (2002), Effects of stress from mine drainage on diversity, biomass, and function of primary producers in mountain streams. Ecosystems Version: 1 5 (6) 554-567, issn: 1432-9840, ids: 595QV, doi: 10.1007/s10021-002-0182-9
  • McCutchan, JH, JF Saunders, WM Lewis and MG Hayden (2002), Effects of groundwater flux on open-channel estimates of stream metabolism. Limnol. Oceanogr. Version: 1 47 (1) 321-324, issn: 0024-3590, ids: 516AM
  • Lewis, WM, SK Hamilton, MA Rodriguez, JF Saunders and MA Lasi (2001), Foodweb analysis of the Orinoco floodplain based on production estimates and stable isotope data. J. N. Am. Benthol. Soc. Version: 1 20 (2) 241-254, issn: 0887-3593, ids: 433JN, doi: 10.2307/1468319
  • Niyogi, DK, WM Lewis and DM McKnight (2001), Litter breakdown in mountain streams affected by mine drainage: Biotic mediation of abiotic controls. Ecol. Appl. Version: 1 11 (2) 506-516, issn: 1051-0761, ids: 418EA, doi: 10.2307/3060905
  • Sjodin, A, WM Lewis and JF Saunders (2001), Analysis of groundwater exchange for a large plains river in Colorado (USA). Hydrol. Process. Version: 1 15 (4) 609-620, issn: 0885-6087, ids: 413MZ, doi: 10.1002/hyp.173
  • Smith, LK, WM Lewis, JP Chanton, G Cronin and SK Hamilton (2000), Methane emissions from the Orinoco River floodplain, Venezuela. Biogeochemistry Version: 1 51 (2) 113-140, issn: 0168-2563, ids: 341HT, doi: 10.1023/A:1006443429909
  • Lewis, WM, SK Hamilton, MA Lasi, M Rodriguez and JF Saunders (2000), Ecological determinism on the Orinoco floodplain. Bioscience Version: 1 50 (8) 681-692, issn: Jun-68, ids: 343QE, doi: 10.1641/0006-3568(2000)050[0681:EDOTOF]2.0.CO;2
  • Lewis, WM, JM Melack, WH McDowell, M McClain and JE Richey (1999), Nitrogen yields from undisturbed watersheds in the Americas. Biogeochemistry Version: 1 46 (3-Jan) 149-162, issn: 0168-2563, ids: 204QU, doi: 10.1007/BF01007577
  • Skaggs, RL, ML Aguin, WM Lewis and JW Birks (1998), Detection of argon by Penning ionization and competitive absorption using a sensitized photoionization detector. Anal. Chem. Version: 1 70 (16) 3493-3497, issn: Mar-00, ids: 111AF, doi: 10.1021/ac9802022
  • McCutchan, JH, WM Lewis and JF Saunders (1998), Uncertainty in the estimation of stream metabolism from open-channel oxygen concentrations. J. N. Am. Benthol. Soc. Version: 1 17 (2) 155-164, issn: 0887-3593, ids: 108JL, doi: 10.2307/1467959
  • Vavilova, VV and WM Lewis (1998), Temporal and altitudinal variations in the attached algae of mountain streams in Colorado. Hydrobiologia Version: 1 390 (3-Jan) 99-106, issn: 0018-8158, ids: 195EJ, doi: 10.1023/A:1003526306724
  • Rodriguez, MA and WM Lewis (1997), Structure of fish assemblages along environmental gradients in floodplain lakes of the Orinoco River. Ecol. Monogr. Version: 1 67 (1) 109-128, issn: 0012-9615, ids: WH237, doi: 10.1890/0012-9615(1997)067[0109:SOFAAE]2.0.CO;2
  • Sjodin, AL, WM Lewis and JF Saunders (1997), Denitrification as a component of the nitrogen budget for a large plains river. Biogeochemistry Version: 1 39 (3) 327-342, issn: 0168-2563, ids: YD252, doi: 10.1023/A:1005884117467
  • Arenz, RF, WM Lewis and JF Saunders (1996), Determination of chlorophyll and dissolved organic carbon from reflectance data for Colorado reservoirs. Int. J. Remote Sens. Version: 1 17 (8) 1547-1566, issn: 0143-1161, ids: UJ901
  • Friedman, JM, WR Osterkamp and WM Lewis (1996), The role of vegetation and bed-level fluctuations in the process of channel narrowing. Geomorphology Version: 1 14 (4) 341-351, issn: 0169-555X, ids: UC058, doi: 10.1016/0169-555X(95)00047-9
  • Friedman, JM, WR Osterkamp and WM Lewis (1996), Channel narrowing and vegetation development following a Great Plains flood. Ecology Version: 1 77 (7) 2167-2181, issn: 0012-9658, ids: VM421, doi: 10.2307/2265710
  • LEWIS, WM and JF SAUNDERS (1995), IMPROVEMENTS IN STREAM AMMONIA MODELS BY SIMULTANEOUS COMPUTATION OF EXTREMES IN FLOW AND WATER CHEMISTRY. Environ. Sci. Technol. Version: 1 29 (7) 1796-1801, issn: 0013-936X, ids: RG467, doi: 10.1021/es00007a016
  • FRIEDMAN, JM, ML SCOTT and WM LEWIS (1995), RESTORATION OF RIPARIAN FOREST USING IRRIGATION, ARTIFICIAL DISTURBANCE, AND NATURAL SEEDFALL. Environ. Manage. Version: 1 19 (4) 547-557, issn: 0364-152X, ids: RC019, doi: 10.1007/BF02471966
  • RODRIGUEZ, MA and WM LEWIS (1994), REGULATION AND STABILITY IN FISH ASSEMBLAGES OF NEOTROPICAL FLOODPLAIN LAKES. Oecologia Version: 1 99 (2-Jan) 166-180, issn: 0029-8549, ids: PJ341, doi: 10.1007/BF00317098
  • HAMILTON, SK, WM LEWIS and SJ SIPPEL (1992), ENERGY-SOURCES FOR AQUATIC ANIMALS IN THE ORINOCO RIVER FLOODPLAIN - EVIDENCE FROM STABLE ISOTOPES. Oecologia Version: 1 89 (3) 324-330, issn: 0029-8549, ids: HJ153
  • MORRIS, DP and WM LEWIS (1992), NUTRIENT LIMITATION OF BACTERIOPLANKTON GROWTH IN LAKE DILLON, COLORADO. Limnol. Oceanogr. Version: 1 37 (6) 1179-1192, issn: 0024-3590, ids: KR914
  • HAMILTON, SK and WM LEWIS (1992), STABLE CARBON AND NITROGEN ISOTOPES IN ALGAE AND DETRITUS FROM THE ORINOCO RIVER FLOODPLAIN, VENEZUELA. Geochim. Cosmochim. Ac. Version: 1 56 (12) 4237-4246, issn: 0016-7037, ids: KF602, doi: 10.1016/0016-7037(92)90264-J
  • MITTON, JB and WM LEWIS (1992), HETEROZYGOSITY AND LIFE-HISTORY VARIATION IN BONY FISHES - RESPONSE. Evolution Version: 1 46 (2) 576-577, issn: 0014-3820, ids: HQ631, doi: 10.2307/2409876
  • UNGER, PA and WM LEWIS (1991), POPULATION ECOLOGY OF A PELAGIC FISH, XENOMELANIRIS-VENEZUELAE (ATHERINIDAE), IN LAKE VALENCIA, VENEZUELA. Ecology Version: 1 72 (2) 440-456, issn: 0012-9658, ids: FE248, doi: 10.2307/2937186
  • RODRIGUEZ, MA and WM LEWIS (1990), DIVERSITY AND SPECIES COMPOSITION OF FISH COMMUNITIES OF ORINOCO FLOODPLAIN LAKES. NATIONAL GEOGRAPHIC RESEARCH Version: 1 6 (3) 319-328, issn: 8755-724X, ids: DL276
  • RODRIGUEZ, MA, SE RICHARDSON and WM LEWIS (1990), NOCTURNAL BEHAVIOR AND ASPECTS OF THE ECOLOGY OF A DRIFTWOOD CATFISH, ENTOMOCORUS-GAMEROI (AUCHENIPTERIDAE). Biotropica Version: 1 22 (4) 435-438, issn: 0006-3606, ids: EQ793, doi: 10.2307/2388565
  • HAMILTON, SK, SJ SIPPEL, WM LEWIS and JF SAUNDERS (1990), ZOOPLANKTON ABUNDANCE AND EVIDENCE FOR ITS REDUCTION BY MACROPHYTE MATS IN 2 ORINOCO FLOODPLAIN LAKES. J. Plankton Res. Version: 1 12 (2) 345-363, issn: 0142-7873, ids: CR963, doi: 10.1093/plankt/12.2.345
  • HAMILTON, SK and WM LEWIS (1990), BASIN MORPHOLOGY IN RELATION TO CHEMICAL AND ECOLOGICAL CHARACTERISTICS OF LAKES ON THE ORINOCO RIVER FLOODPLAIN, VENEZUELA. Arch. Hydrobiol. Version: 1 119 (4) 393-425, issn: 0003-9136, ids: FU564
  • LEWIS, WM (1990), COMPARISONS OF PHYTOPLANKTON BIOMASS IN TEMPERATE AND TROPICAL LAKES. Limnol. Oceanogr. Version: 1 35 (8) 1838-1845, issn: 0024-3590, ids: FE655
  • SAUNDERS, JF and WM LEWIS (1989), ZOOPLANKTON ABUNDANCE IN THE LOWER ORINOCO RIVER, VENEZUELA. Limnol. Oceanogr. Version: 1 34 (2) 397-409, issn: 0024-3590, ids: U5388
  • LEWIS, WM (1989), FURTHER EVIDENCE FOR ANOMALOUS SIZE SCALING OF RESPIRATION IN PHYTOPLANKTON. J. Phycol. Version: 1 25 (2) 395-397, issn: 0022-3646, ids: AC845, doi: 10.1111/j.1529-8817.1989.tb00136.x
  • TWOMBLY, S and WM LEWIS (1989), FACTORS REGULATING CLADOCERAN DYNAMICS IN A VENEZUELAN FLOODPLAIN LAKE. J. Plankton Res. Version: 1 11 (2) 317-333, issn: 0142-7873, ids: T5567, doi: 10.1093/plankt/11.2.317
  • SAUNDERS, JF and WM LEWIS (1989), TRANSPORT OF MAJOR SOLUTES AND THE RELATIONSHIP BETWEEN SOLUTE CONCENTRATIONS AND DISCHARGE IN THE APURE RIVER, VENEZUELA. Biogeochemistry Version: 1 8 (2) 101-113, issn: 0168-2563, ids: AN742
  • LEWIS, WM and JF SAUNDERS (1989), CONCENTRATION AND TRANSPORT OF DISSOLVED AND SUSPENDED SUBSTANCES IN THE ORINOCO RIVER. Biogeochemistry Version: 1 7 (3) 203-240, issn: 0168-2563, ids: AD097, doi: 10.1007/BF00004218
  • MITTON, JB and WM LEWIS (1989), RELATIONSHIPS BETWEEN GENETIC-VARIABILITY AND LIFE-HISTORY FEATURES OF BONY FISHES. Evolution Version: 1 43 (8) 1712-1723, issn: 0014-3820, ids: CH764, doi: 10.2307/2409387
  • SAUNDERS, JF and WM LEWIS (1988), COMPOSITION AND SEASONALITY OF THE ZOOPLANKTON COMMUNITY OF LAKE VALENCIA, VENEZUELA. J. Plankton Res. Version: 1 10 (5) 957-985, issn: 0142-7873, ids: P8813, doi: 10.1093/plankt/10.5.957
  • SAUNDERS, JF and WM LEWIS (1988), TRANSPORT OF PHOSPHORUS, NITROGEN, AND CARBON BY THE APURE RIVER, VENEZUELA. Biogeochemistry Version: 1 5 (3) 323-342, issn: 0168-2563, ids: P0815, doi: 10.1007/BF02180071
  • LEWIS, WM (1988), PRIMARY PRODUCTION IN THE ORINOCO RIVER. Ecology Version: 1 69 (3) 679-692, issn: 0012-9658, ids: N7209, doi: 10.2307/1941016
  • SAUNDERS, JF and WM LEWIS (1988), ZOOPLANKTON ABUNDANCE AND TRANSPORT IN A TROPICAL WHITE-WATER RIVER. Hydrobiologia Version: 1 162 (2) 147-155, issn: 0018-8158, ids: N2762, doi: 10.1007/BF00014537
  • SAUNDERS, JF and WM LEWIS (1988), ZOOPLANKTON ABUNDANCE IN THE CAURA RIVER, VENEZUELA. Biotropica Version: 1 20 (3) 206-214, issn: 0006-3606, ids: P8500, doi: 10.2307/2388235
  • SAUNDERS, JF and WM LEWIS (1988), DYNAMICS AND CONTROL MECHANISMS IN A TROPICAL ZOOPLANKTON COMMUNITY (LAKE VALENCIA, VENEZUELA). Ecol. Monogr. Version: 1 58 (4) 337-353, issn: 0012-9615, ids: R0417, doi: 10.2307/1942544
  • MORRIS, DP and WM LEWIS (1988), PHYTOPLANKTON NUTRIENT LIMITATION IN COLORADO MOUNTAIN LAKES. Freshw. Biol. Version: 1 20 (3) 315-327, issn: 0046-5070, ids: T0991, doi: 10.1111/j.1365-2427.1988.tb00457.x
  • LUNDBERG, JG, WM LEWIS, JF SAUNDERS and F MAGOLECCIA (1987), A MAJOR FOOD WEB COMPONENT IN THE ORINOCO RIVER CHANNEL - EVIDENCE FROM PLANKTIVOROUS ELECTRIC FISHES. Science Version: 1 237 (4810) 81-83, issn: 0036-8075, ids: H9606, doi: 10.1126/science.237.4810.81
  • LEWIS, WM, SK HAMILTON, SL JONES and DD RUNNELS (1987), MAJOR ELEMENT CHEMISTRY, WEATHERING AND ELEMENT YIELDS FOR THE CAURA RIVER DRAINAGE, VENEZUELA. Biogeochemistry Version: 1 4 (2) 159-181, issn: 0168-2563, ids: J3311, doi: 10.1007/BF02180153
  • LEVINE, SN and WM LEWIS (1987), A NUMERICAL-MODEL OF NITROGEN-FIXATION AND ITS APPLICATION TO LAKE VALENCIA, VENEZUELA. Freshw. Biol. Version: 1 17 (2) 265-274, issn: 0046-5070, ids: G5950, doi: 10.1111/j.1365-2427.1987.tb01047.x
  • HAMILTON, SK and WM LEWIS (1987), CAUSES OF SEASONALITY IN THE CHEMISTRY OF A LAKE ON THE ORINOCO RIVER FLOODPLAIN, VENEZUELA. Limnol. Oceanogr. Version: 1 32 (6) 1277-1290, issn: 0024-3590, ids: L6101
  • CRESSA, C and WM LEWIS (1986), ECOLOGICAL ENERGETICS OF CHAOBORUS IN A TROPICAL LAKE. Oecologia Version: 1 70 (3) 326-331, issn: 0029-8549, ids: E3639, doi: 10.1007/BF00379492
  • LEWIS, WM (1986), NITROGEN AND PHOSPHORUS RUNOFF LOSSES FROM A NUTRIENT-POOR TROPICAL MOIST FOREST. Ecology Version: 1 67 (5) 1275-1282, issn: 0012-9658, ids: E1979, doi: 10.2307/1938683
  • LEWIS, WM (1986), PHYTOPLANKTON SUCCESSION IN LAKE VALENCIA, VENEZUELA. Hydrobiologia Version: 1 138 189-203, issn: 0018-8158, ids: E0709, doi: 10.1007/BF00027240
  • LEWIS, WM, JF SAUNDERS, SN LEVINE and FH WEIBEZAHN (1986), ORGANIC-CARBON IN THE CAURA RIVER, VENEZUELA. Limnol. Oceanogr. Version: 1 31 (3) 653-656, issn: 0024-3590, ids: C8635
  • LEWIS, WM, T FROST and D MORRIS (1986), STUDIES OF PLANKTONIC BACTERIA IN LAKE VALENCIA, VENEZUELA. Arch. Hydrobiol. Version: 1 106 (3) 289-305, issn: 0003-9136, ids: C7640
  • LEWIS, WM (1986), EVOLUTIONARY INTERPRETATIONS OF ALLELOCHEMICAL INTERACTIONS IN PHYTOPLANKTON ALGAE. Am. Nat. Version: 1 127 (2) 184-194, issn: 0003-0147, ids: A0176
  • LEWIS, WM, MC GRANT and SK HAMILTON (1985), EVIDENCE THAT FILTERABLE PHOSPHORUS IS A SIGNIFICANT ATMOSPHERIC LINK IN THE PHOSPHORUS CYCLE. Oikos Version: 1 45 (3) 428-432, issn: 0030-1299, ids: AVY59, doi: 10.2307/3565578
  • LEVINE, SN and WM LEWIS (1985), THE HORIZONTAL HETEROGENEITY OF NITROGEN-FIXATION IN LAKE VALENCIA, VENEZUELA. Limnol. Oceanogr. Version: 1 30 (6) 1240-1245, issn: 0024-3590, ids: AVJ10
  • LEWIS, WM (1985), PROTOZOAN ABUNDANCES IN THE PLANKTON OF 2 TROPICAL LAKES. Arch. Hydrobiol. Version: 1 104 (3) 337-343, issn: 0003-9136, ids: APV81
  • LEWIS, WM (1985), NUTRIENT SCARCITY AS AN EVOLUTIONARY CAUSE OF HAPLOIDY. Am. Nat. Version: 1 125 (5) 692-701, issn: 0003-0147, ids: AHJ76
  • LEWIS, WM (1984), THE DIATOM SEX CLOCK AND ITS EVOLUTIONARY SIGNIFICANCE. Am. Nat. Version: 1 123 (1) 73-80, issn: 0003-0147, ids: RX727
  • CRESSA, C and WM LEWIS (1984), GROWTH AND DEVELOPMENT PATTERNS IN A TROPICAL CHAOBORUS SPECIES AND THEIR ECOLOGICAL SIGNIFICANCE. Arch. Hydrobiol. Version: 1 100 (1) 21-28, issn: 0003-9136, ids: SP180
  • LEVINE, SN and WM LEWIS (1984), DIEL VARIATION OF NITROGEN-FIXATION IN LAKE VALENCIA, VENEZUELA. Limnol. Oceanogr. Version: 1 29 (4) 887-893, issn: 0024-3590, ids: TC653
  • LEWIS, WM, MC GRANT and JF SAUNDERS (1984), CHEMICAL-PATTERNS OF BULK ATMOSPHERIC DEPOSITION IN THE STATE OF COLORADO. Water Resour. Res. Version: 1 20 (11) 1691-1704, issn: 0043-1397, ids: TT375, doi: 10.1029/WR020i011p01691
  • UNGER, PA, WM LEWIS and DH MCCLEARN (1984), NONVISUAL FEEDING IN A VISUAL PLANKTIVORE, XENOMELANIRIS-VENEZUELAE. Oecologia Version: 1 64 (2) 280-283, issn: 0029-8549, ids: TN847, doi: 10.1007/BF00376883
  • EPP, RW and WM LEWIS (1984), COST AND SPEED OF LOCOMOTION FOR ROTIFERS. Oecologia Version: 1 61 (3) 289-292, issn: 0029-8549, ids: SH657, doi: 10.1007/BF00379624
  • LEWIS, WM (1984), A 5-YEAR RECORD OF TEMPERATURE, MIXING, AND STABILITY FOR A TROPICAL LAKE (LAKE VALENCIA, VENEZUELA). Arch. Hydrobiol. Version: 1 99 (3) 340-346, issn: 0003-9136, ids: SF837
  • LEWIS, WM and SN LEVINE (1984), THE LIGHT RESPONSE OF NITROGEN-FIXATION IN LAKE VALENCIA, VENEZUELA. Limnol. Oceanogr. Version: 1 29 (4) 894-900, issn: 0024-3590, ids: TC653
  • LEWIS, WM (1983), INTERCEPTION OF ATMOSPHERIC FIXED NITROGEN AS AN ADAPTIVE ADVANTAGE OF SCUM FORMATION IN BLUE-GREEN-ALGAE. J. Phycol. Version: 1 19 (4) 534-536, issn: 0022-3646, ids: SC962, doi: 10.1111/j.0022-3646.1983.00534.x
  • LEWIS, WM (1983), COLLECTION OF AIRBORNE MATERIALS BY A WATER-SURFACE. Limnol. Oceanogr. Version: 1 28 (6) 1242-1246, issn: 0024-3590, ids: RV404
  • LEWIS, WM (1983), A REVISED CLASSIFICATION OF LAKES BASED ON MIXING. Can. J. Fish. Aquat. Sci. Version: 1 40 (10) 1779-1787, issn: 0706-652X, ids: RR929
  • UNGER, PA and WM LEWIS (1983), SELECTIVE PREDATION WITH RESPECT TO BODY SIZE IN A POPULATION OF THE FISH XENOMELANIRIS-VENEZUELAE (ATHERINIDAE). Ecology Version: 1 64 (5) 1136-1144, issn: 0012-9658, ids: RJ868, doi: 10.2307/1937824
  • LEWIS, WM (1983), INTERRUPTION OF SYNTHESIS AS A COST OF SEX IN SMALL ORGANISMS. Am. Nat. Version: 1 121 (6) 825-834, issn: 0003-0147, ids: QR940
  • LEWIS, WM (1983), TEMPERATURE, HEAT, AND MIXING IN LAKE VALENCIA, VENEZUELA. Limnol. Oceanogr. Version: 1 28 (2) 273-286, issn: 0024-3590, ids: QL472
  • LEWIS, WM (1982), VERTICAL EDDY DIFFUSIVITIES IN A LARGE TROPICAL LAKE. Limnol. Oceanogr. Version: 1 27 (1) 161-163, issn: 0024-3590, ids: NA271
  • LEWIS, WM (1982), CHANGES IN PH AND BUFFERING CAPACITY OF LAKES IN THE COLORADO ROCKIES. Limnol. Oceanogr. Version: 1 27 (1) 167-172, issn: 0024-3590, ids: NA271
  • LEWIS, WM and W RIEHL (1982), PHYTOPLANKTON COMPOSITION AND MORPHOLOGY IN LAKE-VALENCIA, VENEZUELA. Int. Rev. Gesamten Hydrobiol. Version: 1 67 (3) 297-322, issn: 0020-9309, ids: PA477
  • GRANT, MC and WM LEWIS (1982), CHEMICAL LOADING RATES FROM PRECIPITATION IN THE COLORADO ROCKIES. Tellus Version: 1 34 (1) 74-88, issn: 0040-2826, ids: NF076
  • EPP, RW and WM LEWIS (1981), PHOTOSYNTHESIS IN COPEPODS. Science Version: 1 214 (4527) 1349-1350, issn: 0036-8075, ids: MT154, doi: 10.1126/science.214.4527.1349
  • LEWIS, WM and FH WEIBEZAHN (1981), ACID-RAIN AND MAJOR SEASONAL-VARIATION OF HYDROGEN-ION LOADING IN A TROPICAL WATERSHED. ACTA CIENTIFICA VENEZOLANA Version: 1 32 (3) 236-238, issn: 0001-5504, ids: NE515
  • LEWIS, WM and FH WEIBEZAHN (1981), CHEMISTRY OF A 7.5-M SEDIMENT CORE FROM LAKE VALENCIA, VENEZUELA. Limnol. Oceanogr. Version: 1 26 (5) 907-924, issn: 0024-3590, ids: MK658
  • LEWIS, WM and F WEIBEZAHN (1981), THE CHEMISTRY AND PHYTOPLANKTON OF THE ORINOCO AND CARONI RIVERS, VENEZUELA. Arch. Hydrobiol. Version: 1 91 (4) 521-528, issn: 0003-9136, ids: ME498
  • LEWIS, WM and MC GRANT (1981), EFFECT OF THE MAY-JUNE MOUNT ST-HELENS ERUPTIONS ON PRECIPITATION CHEMISTRY IN CENTRAL COLORADO. Atmos. Environ. Version: 1 15 (9) 1539-1542, issn: 1352-2310, ids: MB442, doi: 10.1016/0004-6981(81)90136-0
  • LEWIS, WM (1981), PRECIPITATION CHEMISTRY AND NUTRIENT LOADING BY PRECIPITATION IN A TROPICAL WATERSHED. Water Resour. Res. Version: 1 17 (1) 169-181, issn: 0043-1397, ids: LD922, doi: 10.1029/WR017i001p00169
  • BRADBURY, JP, B LEYDEN, M SALGADOLABOURIAU, WM LEWIS, C SCHUBERT, MW BINFORD, DG FREY, DR WHITEHEAD and FH WEIBEZAHN (1981), LATE QUATERNARY ENVIRONMENTAL HISTORY OF LAKE VALENCIA, VENEZUELA. Science Version: 1 214 (4527) 1299-1305, issn: 0036-8075, ids: MT154, doi: 10.1126/science.214.4527.1299
  • LEWIS, WM and MC GRANT (1980), ACID PRECIPITATION IN THE WESTERN UNITED-STATES. Science Version: 1 207 (4427) 176-177, issn: 0036-8075, ids: HZ705, doi: 10.1126/science.207.4427.176
  • LEWIS, WM and MC GRANT (1980), RELATIONSHIPS BETWEEN SNOW COVER AND WINTER LOSSES OF DISSOLVED SUBSTANCES FROM A MOUNTAIN WATERSHED. Arct. Alp. Res. Version: 1 12 (1) 11-17, issn: 0004-0851, ids: JH458, doi: 10.2307/1550586
  • EPP, RW and WM LEWIS (1980), METABOLIC UNIFORMITY OVER THE ENVIRONMENTAL-TEMPERATURE RANGE IN BRACHIONUS-PLICATILIS (ROTIFERA). Hydrobiologia Version: 1 73 (3-Jan) 145-147, issn: 0018-8158, ids: KF096, doi: 10.1007/BF00019439
  • EPP, RW and WM LEWIS (1980), THE NATURE AND ECOLOGICAL SIGNIFICANCE OF METABOLIC CHANGES DURING THE LIFE-HISTORY OF COPEPODS. Ecology Version: 1 61 (2) 259-264, issn: 0012-9658, ids: KD173, doi: 10.2307/1935183
  • LEWIS, WM and MC GRANT (1980), EFFECT OF URBAN SOURCES ON ACID PRECIPITATION IN THE WESTERN UNITED-STATES - REPLY. Science Version: 1 210 (4473) 1043-1043, issn: 0036-8075, ids: KR043, doi: 10.1126/science.210.4473.1043-a
  • LEWIS, WM and JF SAUNDERS (1979), 2 NEW INTEGRATING SAMPLERS FOR ZOOPLANKTON, PHYTOPLANKTON, AND WATER CHEMISTRY. Arch. Hydrobiol. Version: 1 85 (2) 244-249, issn: 0003-9136, ids: GV264
  • DEINFANTE, A, O INFANTE, M MARQUEZ, WM LEWIS and FH WEIBEZAHN (1979), CONDITIONS LEADING TO MASS MORTALITY OF FISH AND ZOOPLANKTON IN LAKE VALENCIA VENEZUELA. ACTA CIENTIFICA VENEZOLANA Version: 1 30 (1) 67-73, issn: 0001-5504, ids: HL682
  • EPP, RW and WM LEWIS (1979), METABOLIC RESPONSES TO TEMPERATURE-CHANGE IN A TROPICAL FRESHWATER COPEPOD (MESOCYCLOPS-BRASILIANUS) AND THEIR ADAPTIVE SIGNIFICANCE. Oecologia Version: 1 42 (2) 123-138, issn: 0029-8549, ids: HP799, doi: 10.1007/BF00344853
  • LEWIS, WM and MC GRANT (1979), CHANGES IN THE OUTPUT OF IONS FROM A WATERSHED AS A RESULT OF THE ACIDIFICATION OF PRECIPITATION. Ecology Version: 1 60 (6) 1093-1097, issn: 0012-9658, ids: JS622, doi: 10.2307/1936955
  • EPP, RW and WM LEWIS (1979), SEXUAL DIMORPHISM IN BRACHIONUS-PLICATILIS (ROTIFERA) - EVOLUTIONARY AND ADAPTIVE SIGNIFICANCE. Evolution Version: 1 33 (3) 919-928, issn: 0014-3820, ids: HR242, doi: 10.2307/2407655
  • LEWIS, WM and MC GRANT (1979), RELATIONSHIPS BETWEEN STREAM DISCHARGE AND YIELD OF DISSOLVED SUBSTANCES FROM A COLORADO MOUNTAIN WATERSHED. Soil Sci. Version: 1 128 (6) 353-363, issn: 0038-075X, ids: JA516, doi: 10.1097/00010694-197912000-00007
  • LEWIS, WM (1978), DYNAMICS AND SUCCESSION OF THE PHYTOPLANKTON IN A TROPICAL LAKE - LAKE LANAO, PHILIPPINES. J. Ecol. Version: 1 66 (3) 849-880, issn: 0022-0477, ids: GF551, doi: 10.2307/2259300
  • LEWIS, WM (1978), ANALYSIS OF SUCCESSION IN A TROPICAL PHYTOPLANKTON COMMUNITY AND A NEW MEASURE OF SUCCESSION RATE. Am. Nat. Version: 1 112 (984) 401-414, issn: 0003-0147, ids: EX444
  • LEWIS, WM (1978), COMPOSITIONAL, PHYTOGEOGRAPHICAL AND ELEMENTARY STRUCTURAL-ANALYSIS OF PHYTOPLANKTON IN A TROPICAL LAKE - LAKE LANAO, PHILIPPINES. J. Ecol. Version: 1 66 (1) 213-226, issn: 0022-0477, ids: EY131, doi: 10.2307/2259189
  • LEWIS, WM (1978), COMPARISON OF TEMPORAL AND SPATIAL VARIATION IN ZOOPLANKTON OF A LAKE BY MEANS OF VARIANCE COMPONENTS. Ecology Version: 1 59 (4) 666-671, issn: 0012-9658, ids: GB333
  • LEWIS, WM and MC GRANT (1978), SAMPLING AND CHEMICAL INTERPRETATION OF PRECIPITATION FOR MASS BALANCE STUDIES. Water Resour. Res. Version: 1 14 (6) 1098-1104, issn: 0043-1397, ids: GC389, doi: 10.1029/WR014i006p01098
  • LEWIS, WM (1978), SPATIAL-DISTRIBUTION OF THE PHYTOPLANKTON IN A TROPICAL LAKE (LAKE LANAO, PHILIPPINES). Int. Rev. Gesamten Hydrobiol. Version: 1 63 (5) 619-635, issn: 0020-9309, ids: GU121, doi: 10.1002/iroh.19780630508
  • LEWIS, WM (1977), ECOLOGICAL SIGNIFICANCE OF SHAPES OF ABUNDANCE-FREQUENCY DISTRIBUTIONS FOR COEXISTING PHYTOPLANKTON SPECIES. Ecology Version: 1 58 (4) 850-859, issn: 0012-9658, ids: DV440, doi: 10.2307/1936220
  • LEWIS, WM (1977), FEEDING SELECTIVITY OF A TROPICAL CHAOBORUS POPULATION. Freshw. Biol. Version: 1 7 (4) 311-325, issn: 0046-5070, ids: DS274, doi: 10.1111/j.1365-2427.1977.tb01679.x
  • LEWIS, WM and D CANFIELD (1977), DISSOLVED ORGANIC-CARBON IN SOME DARK VENEZUELAN WATERS AND A REVISED EQUATION FOR SPECTROPHOTOMETRIC DETERMINATION OF DISSOLVED ORGANIC-CARBON. Arch. Hydrobiol. Version: 1 79 (4) 441-445, issn: 0003-9136, ids: DN108
  • LEWIS, WM (1977), NET GROWTH-RATE THROUGH TIME AS AN INDICATOR OF ECOLOGICAL SIMILARITY AMONG PHYTOPLANKTON SPECIES. Ecology Version: 1 58 (1) 149-157, issn: 0012-9658, ids: DJ641, doi: 10.2307/1935116
  • LEWIS, WM (1977), COMMENTS ON ANALYSIS OF GRAZING IN LAKE ERKEN. Limnol. Oceanogr. Version: 1 22 (5) 966-967, issn: 0024-3590, ids: DV903
  • LEWIS, WM (1976), SURFACE/VOLUME RATIO - IMPLICATIONS FOR PHYTOPLANKTON MORPHOLOGY. Science Version: 1 192 (4242) 885-887, issn: 0036-8075, ids: BR576, doi: 10.1126/science.192.4242.885
  • LEWIS, WM (1976), OBSERVATIONS ON SUPERFICIAL SEDIMENT TEMPERATURES OF SOME LAKES IN SOUTHEASTERN UNITED-STATES. Freshw. Biol. Version: 1 6 (1) 49-57, issn: 0046-5070, ids: BG441, doi: 10.1111/j.1365-2427.1976.tb01590.x
  • LEWIS, WM (1975), THEORETICAL COMPARISON OF ATTENUATION OF LIGHT ENERGY AND QUANTA IN WATERS OF DIVERGENT OPTICAL-PROPERTIES. Arch. Hydrobiol. Version: 1 75 (3) 285-296, issn: 0003-9136, ids: AL213
  • LEWIS, WM (1974), ANALYSIS OF SURFACE SLICKS IN A RESERVOIR RECEIVING HEATED EFFLUENT. Arch. Hydrobiol. Version: 1 74 (3) 304-315, issn: 0003-9136, ids: U9195