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Response of an Antarctic Lake Ecosystem to Climate Variation: Linkages between Phytoplankton Species Dynamics and Streamflow Diane M. McKnight 1, Erin

Dec 29, 2015

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  • Response of an Antarctic Lake Ecosystem to Climate Variation: Linkages between Phytoplankton Species Dynamics and StreamflowDiane M. McKnight1, Erin Von Maytre1,John C. Priscu2,W. Berry Lyons3, and Michael Gooseff1

    1. Institute of Arctic and Alpine Research Boulder, CO2. Dept. of Biology, Montana State University, Bozeman, MT3. Byrd Polar Research Institute, Ohio State University, Columbus, OH

  • Background Ice Covered LakesIce cover- 3-5 m thick, moat in summerSource- streamflow from glacial melt Loss- ablation of ice coverWater column- stable w/depth, some lateral circulationLight penetration about 1% or less

  • Main Phytoplankton SpeciesChlamydomonus intermediaOscillatoria lineneticaChlamydomonas subcaudata

  • Main Phytoplankton SpeciesPhormidium angustissimumChroomonas lacustrisStarburst protazoa

  • Dominant species occur in depth zones

  • Dry Valleys and Global Climate

  • Interannual variability in phytoplankton

  • Depth-wise Zonation

    TaxaSize(mm3)Depths (m)% PAR1987-1991:Oscillatoria sp.45-70.5-1.6Oscillatoria limnetica26-8.50.2-0.9Cryptomonas sp.2767.5-9.50.1-0.4Chroomonas lacustris1308.5-90.16-0.2Pyramimonas sp.5839-100.16-0.2Phormidium angustissimum29.5-10.50.16-0.2Chlamydomonas subcaudata904various0.16-0.2

  • Depth-wise Zonation cont* Vincent, 1981** Vincent, 1988

    TaxaSize(mm3)Depths (m)% PAROchromonas nannos*170*4.5-6.50.7-1.0**Chlamydomonas sp.64.5-8.50.4-1.0Cryptomonas sp3084.5-8.50.4-1.0Chroomonas lacustris1778.5-9.50.2-0.4Pyramimonas sp.3358.5-9.50.2-0.4

  • NRNRNR

  • Chroomonas lacustris Biovolume

  • Chlamydomonas intermediaPhormidium angustissimum Oscillatoria limnetica Chroomonas lacustris Cryptomonas sp.Lake Fryxell 1997-98 Biovolume (mm3/mL)Nov. 18Dec. 29

  • Chlamydomonas intermedia Biovolume

  • Oscillatoria limnetica Biovolume

  • Phormidium angustisimum Biovolume

  • Phytoplankton species changes

  • Potential Factors Controlling PhytoplanktonLight regime in summerNutrients (N)- diffusion from below oxycline and input from streamsMixotrophy and overwinter persistenceMicrobial loop dynamics

  • Cyanobacterial mats in stream

  • Stream algal mat changes

    StreamHabitatMatsChange from 1994-98CanadapavementabundantnoneBowlespavementabundantnoneGreenpavementabundantnew green matsDelta (upper)pavementabundantnew mossHueysandysparsemore orange, new blackDelta (lower)sandysparsenew orangeVon Guerardsandysparsemore matsLawsonsteepsparsemore orange & moss

  • NRNRNDNDND

  • mQmQNRNRNDND

  • Summarizing - trends 1987-99Streamflow- high flow followed by sustained low flowMajor ions increased in upper water columnStream mats-recovery followed by decreaseStream nutrient fluxes- variable!!

  • ConclusionsPhytoplankton response to changing climate occurs at the species levelPatterns for chlorophytes and cryptophytes related to flow regimeIncreasing cyanobacterial abundance Potential factors include light regime, nutrient fluxes, mixotrophy, and major ion chemistry

  • A few words of Thanks:National Science Foundation Project No. OPP-9211773, McMurdo Dry Valleys LTER.MCMLTER colleaguesAntarctic Support Associates staff

    Delta Stream overviewpics of phytoplankton species12 year stream flow recordentire record, biovolume graph 4biovolume vs depth plots from Erin for 1997-98entire record, biovolume graph 3entire record, biovolume graph 2entire record, biovolume graph 110 yr nutrient and flow trends10 yr trend for Delta Stream

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