High mountain lakes as geobiological laboratories

Transcription

1 High mountain lakes as geobiological laboratories Kurt Hanselmann Microbial Ecdology Group 1 Why we turned around below point Photos: Thomas Wiesinger und Roland Meister, SLF Begin of steep hill side 2 Hans Kreis Furgga 3 Research station 4 Jöri lake XIII

2 The thoughts discussed here will aid in answering the excursion topics 1. How can nutrients accumulate and be scavenged in oligotrophic, remote environments? (The role of the iron cycle for nutrient accumulation in Lake Jöri XIII). (Hydrogeochemistry) 2. What are microbial life styles with very low nutrient concentrations and strategies to acquire nutrients? (Microbiology of mats & biofilms in nutrient poor flowing and stagnant waters) 3. Microbial life in cold-extreme environments: are there psychrophilic adaptations? 4. What are physical and chemical determinants that regulate habitat conditions in high mountain lakes? (Microbial ecology: Adaptation to low temperatures, intensive solar radiation and long periods of darkness) 5. How do microbial communities respond to extreme and extremely variable habitat conditions? (Microbial ecology: Regulation of community diversity) 6. The microbial diversity in lake XIII is enormous and extremely variable. How can this observation be explained? 3 Movies 4

3 Ecosystem studies involve the interaction of chemical and physical determinants with life processes 5 Ecosystem determinants Determinants characterizing the habitat Determinants characterizing the organisms Life styles Life cycle processes Modes of interactions Community regulation and evolution Determinants characterizing the living conditions 6

4 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 7 Jöri Lakes 8

5 Inner alpine regions have less precipitation Distribution of precipitation in the Alps Jöri Lakes 9 Erosion of rock minerals, water composition, inputs via the atmosphere and atmospheric fluctuations determine the location where organisms will thrive 10

6 Systems approach to microbial ecology: Interactions between physical, chemical and biological ecosystem determinants Determinants characterizing the habitat size / scale / dimension / volume space topology surfaces substratum location stability over time 11 Panorama Jöri lakes. Our interest is in lake XIII Jöri glacier Lake XIII Lake II Lake I Jöri glacier Lake III Lake II Lake XII Lake I Lake XIII 12

7 Location of Jöri Lake XIII 10.4 Altitude 2640m Isobaths: 1m Distance 13 Geological map of the Jöri Lake area X Lake I II XIII XII Lake III XIV VII 14

8 Jöri lakes I - XXII 15 Jöri lakes I - XIII around 1920 after Hans Kreis 16

9 XVII XVIII Jöri glacier XV XIV XVII 17 XIV Lake XIII in the course of time and seasons Jöri glacier Winterlücke 1928 Jöri glacier 1928 Lake XIII Jöri glacier Winterlücke Jöri glacier Winterlücke Lake XIII August Lake XIII July 18

10 Retreat of the Jöri glacier 1928, 1967, Jöri Lakes Model systems for studying the role of particles in nutrient scavenging and the role of the biogeochemical iron and phosphorus cycles in ecosystem evolution Jöri XIII - S Jöri XIII - S Jöri XIII - N 20

11 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 21 Growth in low-nutrient aquatic environments High affinity for nutrients: Organisms with low K m for any nutrient. = physiological selection Mud covered cyanobacterial mats, Tambo Hydrurus sp., Jör i Alternative nutrient sources Erosion particles with high chemical surface activity. = geochemically regulated selection 22

12 Biofilms: mode of growth in oligotrophic environments Retaining nutrients within the community = ecological selection Cyanobacterial biofilms on rocks. Tambo-lakes Algal mats on rocks. Jöri-lakes (during melting of the ice!) 23 The large number of insect larvae implies that Jöri lake XIII can supply enough food for the insects to develop and thrive 24

13 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 25 The variations in the chemical and physical states of the environment determine the conditions for life processes 26

14 What do the terms imply for mountain lake ecosystem conditions? Determinants characterizing the living conditions acidity / alkalinity proton activity buffering capacity gase solubility dryness water activity solutes: kinds, concentrations, activities, toxicity nutrients: scavenging flow gradients redox state heat flow radiation field material stoichiometries mass fluxes energy fluxes product disposal thermodynamic state diffusion advection mixing shear stress hydrodynamic flow field 27 N, P, Fe, Mn in Jöri Lake XIII (270805) Sample Unit J_XIII_IF J_XIII_OF J_XIII_01 J_XIII_10 Depth [meter] Ammonium NH4+!mol/l Nitrate NO3-!mol/l Nitrogen total NH4-N+NO3-N!atom N/l Nitrogen ratio NO3-N/NH4-N Phosphorus total unfiltered P-tot!mol/l Phosphorus total filtered P-tot-filt!mol/l Iron total Fe-tot!mol/l Manganese total Mn-tot!mol/l N-total / P-tot-filt Fe-tot/P-part Dissolve organic carbon DOC!g/l

15 Ecological determinants * solar radiation * lake mixing * energy budget * wind forces 29 Reflection and transmission of solar irradiance 30

16 The heat budget and heat exchanges determine the time of freezing and thawing 31 Winter and summer density stratification and temperature inversion 32

17 Spring and fall mixing 33 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 34

18 Growth of Cyanobacteria in colonies on very fine erosion particles glacial erosion deposits in lake XIV 10 cm 35 Sizes of erosion particles from top sediment layer cumulative mass finer [%] particlesize 18 % < 0.2 µm 47 % > 0.2 and < 2 µm 22 % > 2 and < 5 µm 13 % > 5 µm equivalent spherical diameter [µm]

19 Surface chemical reactivity of erosion particles: Adsorption and release of ammonia from clay particles of Jöri lake III 37 Distribution of suspended nano and micro particles 38

20 High productivity in a low-nutrient environment The penetration of radiation (here UV-A light) into a water body is diminished by absorption and scattering. In lake XIII scattering of is due to small planktonic organisms which scatter the light. This indicates a high productivity. Red: theoretical penetration into pure water Green: penetration into comparable Gossenköllersee (Austrian Alps) Black: penetration into Jöri lake XIII 39 Question 1: Where do the nutrients come from? Nutrients of atmospheric origin Nutrients of lithospheric origin Nutrients of biospheric origin Question 2: How are they scavenged and how do they remain in the ecosystem? 40

21 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 41 Geological map of the Jöri Lake area X Lake I II XIII XII Lake III XIV VII 42

22 Mineral phases Orthogneis Ankerite 43 Mineral composition of rocks present in the Jöri catchment Feldspar [K,Na,Ca](AlSi 3 O 8 ) Micas: Muscovites KAl 2 (AlSi 3 O 10 )(F,OH) Biotites K(Mg,Fe) 3 [AlSi 3 O 10 (OH,F) 2 Chlorite (Mg, Fe, Al) 6 [(Al,Si) 4 O 10 (OH) 8 Amphibolites metamorphic rock mostly amphibole and plagioclase Quarz SiO 2 Hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 Ankerite Unknown Fe x Mg y Ca z (CO 3 ) x+y+z a mineral in the Jöri-rocks which contains manganese Mathias Katchebesibo, University of Konstanz 44

23 Composition of Aluminum Silicates: e.g. Muscovite and Biotite Muscovite Group: Micas Class: Silicates Composition: Potassium, K 9.81 % Aluminum, Al % Silicon, Si % Hydrogen, H 0.46 % Oxygen, O % Fluorine, F 0.95 % Empirical Formula: KAl 3 Si 3 O 10 (OH) 18 F 0.2 Chemical Formula: KAl 2 (AlSi 3 O 10 )(F,OH) Molecular Weight gm/mol Potassium aluminum silicate hydroxide fluoride Biotite Group: Micas Class: Silicates Composition: Potassium, K 9.02 % Aluminum, Al 6.22 % Silicon, Si % Hydrogen, H 0.41 % Oxygen, O % Fluorine, F 1.10 % Magnesium, Mg 14.02% Iron, Fe 6.44% Empirical Formula: KMg 2.5 Fe 0.5 AlSi 3 O 10 (OH) 1.75 F 0.25 Chemical Formula: K(Mg,Fe) 3 [AlSi 3 O 10 (OH,F) 2 Molecular Weight gm/mol Potassium magnesium iron aluminum silicate hydroxide fluoride 45 Examples of chemical weathering reactions that lead to nutrienttype ions and chemically reactive clays Dissolution of Feldspar: [K,Na,Ca](AlSi 3 O 8 ), a source for potassium and bicarbonate e.g. K-Feldspar 3 K(AlSi 3 O 8 ) + 2 H 2 CO H 2 O 2 K HCO H 4 SiO 4 + KAl 3 Si 3 O 10 (OH) 2 e.g. K-Mica Dissolution of Biotite: K(Mg,Fe) 3 [AlSi 3 O 10 (OH,F) 2, a source for K +, Mg 2,Fe 2+, F - and HCO 3 - e.g. K,Mg,Fe-Biotite KMg 2 FeAlSi 3 O 10 (FOH) + 6 H 2 CO H 2 O 46 K Mg 2+ + Fe HCO H 4 SiO 4 + F Al 2 Si 2 O 5 (OH) 4 e.g. Kaolinite

24 Nutrients from rock erosion; Apatite, e.g. Ca 10 (PO 4 ) 6 (OH) 2 is a source for P but is very hard to dissolve through weathering processes Group: Apatite Class: Phosphates Marino Maggetti, Fribourg. Ap Apatite, Q Quarz Composition: Calcium % Ca Phosphorus % P Hydrogen 0.07 % H Chlorine 2.32 % Cl Oxygen % O Fluorine 1.24 % F Empirical Formula: Ca 5 (PO 4 ) 3 (OH) F Cl Chemical Formula: Ca 5 (PO 4 ) 3 (OH,F,Cl) Molecular Weight = gm/mol Calcium (Fluoro, Chloro, Hydroxyl) Phosphate 47 Chemical weathering of P and Fe containing minerals: sources for P and Fe Dissolution of Hydroxyapatite - a source for phosphate Ca 10 (PO 4 ) 6 (OH) HCO 3-10 CaCO H HPO H 2 O Dissolution of Ankerite - a source for iron Fe x Mg y Ca z (CO 3 ) x+y+z + (x+y+z) H + xfe 2+ + ymg 2+ + zca 2+ + (x+y+z) HCO O 2 FeOOH, Fe 2 O 3 can dissolve hydroxyapatite rusty surface varnish and other minerals on rocks 48

25 Elemental mapping of surface coating (rock varnish) with EDX micro-probe Element Series norm. C Atom. C Oxide Oxid. C [wt.-%] [at.-%] [wt.-%] Iron K series FeO Silicon K series SiO Aluminium K series Al 2 O Sodium K series Na 2 O 3.28 Potassium K series K 2 O 0.86 Manganese K series MnO Phosphorus K series P 2 O Magnesium K series MgO 3 Calcium K series CaO 2.12 Lead M series PbO 5.88 Sulfur K series 0 0 SO Oxygen K series Surface varnish contains a lot of Fe and Mn oxides and some P which is scavenged by the metal oxides 49 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 50

26 Iron is everywhere: Iron cycling is a dominant process In inflow channels At the bottom of the lake On sediment surfaces Around rocks at the lake surface On rock surfaces 51 Iron from and on rocks Jöri glacier Lake XIII Glacial moraines Lake III Inflow channel Submersed rocks 52

27 Geobiological redox processes in iron cycling Caroline Amberg - Brunner, Can you design a similar scheme for the manganese cycle in Jöri lake XIII? 54

28 Solid state redox indicators Mn-oxides Fe-oxides 10 cm 55 Manganese oxides and iron oxides which precipitate on rocks are indicators of ongoing redox cycles at the sediment-water interface Standard electrode potentials of some metabolic reactions (1 Mol/l, 1 atm, ph 7) Couple E [mv] e - transferred CO 2 / CO CO 2 / Glucose H + / H CO 2 / Acetate CO 2 / CH SO 2-4 / H 2 S Oxaloacetate / Malate Fumarate / Succinate Fe 3+ / Fe NO / NO SeO / SeO NO - 3 / 1 / 2 N Mn 4+ / Mn / 2 O 2 / H 2 O N 2 O / N

29 Stability diagrams Eh-pH diagram for Fe-O-H and Mn-O-H 1 FeSO 4 + Fe(OH) 2 + seawater vent water 1 seawater vent water Eh (volts) Fe ++ Pyrite Fe(OH) 3 (ppd) Fe(OH) 4 - Eh (volts) Mn ++ MnO 2 Mn 2 O 3 Mn 3 O FeO(c) -0.5 MnS MnCO 3 Mn(OH) ph [SO 4 2- ] = 10-3 [Fe tot ] = 10-5 [HCO 3 - ] = ph [SO 4 2- ] = 10-3 [Mn tot ] = 10-5 [HCO 3 - ] = Solid state representation of redox transitions 58

30 Solid state representation of redox transitions 59 Dark varnish on submersed rocks indicate biogeochemical dissolution and precipitation 60

31 P associates with Fe & Mn: Electron dispersive element mapping (rock Jöri 37a) Si 61 Fe Mn P Iron oxide precipitates at the sediment surface are indicators that Iron oxide redox-cycling precipitates takes at the place sediment at the surface sediment-water are indicators interface that redoxcycling takes place at the sediment-water interface Fe-oxides Fe-oxides 62

32 Lake XIII cores 63 Lake XIII cores 64

33 Processes at the sediment-water interface 65 Iron mediated processes in Jöri Lake XIII Norbert Swoboda,

34 Radiation driven iron cycling 67 Emmenegger et al Seasonal phosphate and iron release and entrappment Gabriela Iqba l- Nava,

35 Seasonal N/P-ratio changes Gabriela Iqba l- Nava, Iron and phosphate cycling during ice cover period 70

36 Iron and phosphate cycling during ice free period 71 Coupled iron - phosphate cycle in earth history 72

37 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 73 How P is scavenged: Adsorption vs. Co-precipitation adsorbed phosphate ferrihydrite coated particle ferrihydrite precipitate ferrihydrite precipitate ferrihydrite precipitate coprecipitated phosphate ferrihydrite precipitate 74

38 Low nutrient concentrations preferentially support growth of cyanobacteria biomass wet [mg] Biomass wet weight [mg] High nutrient medium (80!S/cm, left). Low nutrient medium (15!S/cm, right). Growth as biofilm for 30 days. Blue: filamentous cyanobacteria, yellow: other organisms, left columns: beginning of experiment right columns: end of experiment 1 0 TPN 05 NM Philipp Roelli, Growth on uncoated Fe ox or Fe ox +P coated particles total wet weight of biomass [mg] Fe: Fe-oxyhydroxide- coating without phosphate Fe/P: Particles coated with Feoxyhydroxide-phosphate complexes Reactor run with medium devoid of P, for 62 days, conductivity 12!S/cm. blue: filamentous cyanobacteria, yellow: other micro-organisms 0 Without Fe or P Fe Fe/P left column beginning, right column end of experiment Philipp Roelli,

39 Microbial growth on iron-phosphate-oxides Blank: no iron, no phosphate, no inoculum Blank: no iron, no phosphate, inoculum (Jöri XIII-sediment) Iron-oxide, no phosphate, inoculum (Jöri XIII-sediment) Iron-phosphateoxides, inoculum (Jöri XIIIsediment) Nutrient-poor medium, no phosphate, no iron Anoxic conditions (CO 2 /N 2 -atmosphere) Fe 2+ and phosphate determination 77 Growth on Fe-P i -oxides Solubility Fe 2+ in anoxic pore water: ~10-3 M Fe 3+ in equilibrium with ferrihydrite: < 10-8 M P i P i Fe(III) Fe(III) Microbial Fe(III) reduction Fe(II) P i Fe(II) P i Caroline Amberg - Brunner,

40 Possible structures of iron oxyhydroxides and iron phosphates 79 Release dynamics: Leaching erosion particles from sediments species [!mol/l] experiment Na-Dithionite extraction Fe 2+ Ca 2+ Mg 2+ Na + K + NH NO 3 PO 4 SO nm nm aqueous leaching 1 nd aqueous leaching 2 nd < < CaCl 2 extraction nm nm nm < nm = not measured nd = not detected Matthias Wagner, Ph.D. Thesis

41 Systems approach to microbial ecology: Interactions between physical, chemical and biological ecosystem determinants 81 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 82

42 Sahara dust event over Europe February, 21, 2004 the dust carries fine particles loaded with nutrients into remote high altitides 83 Dust events are most common during summer 84

43 The global transport of dust Dale W. Griffin, Christina A. Kellogg, Virginia H. Garrison and Eugene A. Shinn, American Scientist, Volume 90, 2002, How Saharan dust is transported to JFJ Back trajectory and uplift of air masses arriving at Jungfraujoch on March 28, 2002, 12:00 Martine Collaud Coen et al, 2004, Meteo Swiss 86

44 48h- Total solid particle mass concentrations 87 Martine Collaud Coen et al, 2004, Meteo Swiss Acid generation in the atmosphere 88

45 Nutrients from remote locations transported via the atmosphere 89 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 90

46 Glacial ice can store and release nutrients from rock erosion and from the atmosphere in cryoconite holes 91 Low temperature habitats: Cryoconite holes 92

47 Melting snow releases enough nutrients to initiate flagellate blooms: red snow on Jöri lake XIII and brown snow on the snow banks along the lake in July 93 Red snow in spring, mostly Chlamydomonas sp. 94

48 Brown snow: mostly Chloromonas sp. 95 The red color (carotenoids) stems from Aplanospores of Chlamydomonas sp. 40x BF 20x BF 96

49 Overview: microorganisms in snow, a great variety 97 Bacterial diversity in snow 98

50 Sampling the microbial snow archive at JFJ you will almost always find a large diversity of microorganisms 100

51 Bacterial, archaeal and eukaryotic diversity in Jungfraujoch snow 101 Bacterial and eukaryotic diversity in Jungfraujoch ice communities 102

52 Sampling microbes from the air 103 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 104

53 Organisms emerge as a consequence of the conditons in the habitat 105 T-profiles A - D: conditions when the samples for diversity analysis were collected 106 Gabriela Iqbal-Nava (2003)

54 Seasonal Community Shifts of Algae in Jöri XIII Dbr Dbr sf A Mrp B Mrp D Mrp C 107 A: ice melting, B: end of ice melting, C: late summer, D: beginning of ice melting Gabriela Iqbal-Nava (2003) Molecular community analysis: strategy Biofilm DNA DNA from isolates Steps: PCR products (16S rdna) ARDRA! TTGE " & DGGE # Comparison Cloning Sequencing Identification Probe design In Situ Hybridization RCCH* Detection 108!Amplified Ribosomal DNA Restriction Analysis "Temporal Temperature Gradient Gel Electrophoresis *Reverse Capture Checkerboard Gene Probe Hybridization #Denaturing Gradient Gel Electrophoresis

55 Large fluctuations in habitat conditons: annual temperature at different depths of Lake Jöri XIII 15 Jul 02 4 Aug Aug Sep Oct 01 3 Feb May Aug 02 Snow fall in the middle of summer is nothing unusual. It cools down the lake surface which can lead to mixing of the entire water column Gabriela Iqbal-Nava (2003) 109 Selected temperature-profiles Temperature profiles of Lake Jöri XIII 0 ice-covered Temperature ( o C) ice-free Depth (m) A D B 8 9 C Jun Jul Jul-02 7-Aug Aug Aug-02 9-Sep Sep-02 1-Oct Oct-02 5-Dec-02 A - D: conditions when the samples for diversity analysis were collected Gabriela Iqbal-Nava (2003) 110

56 Seasonal nutrient fluctuations A - D: conditons when the samples für diversity analysis were collected 111 Gabriela Iqbal-Nava (2003) The most abundant bacteria present in summer depth (m) Bands, closest known-species, similarity B10: Simonsiella steedae, 88% B9: Aquaspirillum delicatum, 97% B8: Aquaspirillum delicatum, 97% B7: Chlorella saccharophila chloroplast, 96% B6: Bosea minatitlanensis, 94% B5: Verrucomicrobiae, 95% B4: Kinetoplastibacterium crithidii, 94% B3: Achromobacter xylosoxidans, 96% B2: Aquaspirillum delicatum, 97% B1: Gemmatimonas aurantiaca, 97% 112 Munti Yuhana (2003) Also present in end of ice cover period summer autumn early winter

57 Most abundant bacteria present in autumn Bands, closest known-species, similarity C12: Trojanella thessalonices, 89% depth (m) 113 C11: Aquaspirillum delicatum, 97% C10: Ultramicrobacterium, 95% C9: Chlorella saccharophila chloroplast, 96% C8: Nostocoida limicola III, 86% C7: Polaromonas vacuolata, 97% C6: Rhodoferax ferrireducens, 98% C5: Sphingomonas sp., 92% C4: Polynucleobacter necessarius, 98% C3: Frankia sp., 91% C2: Gluconacetobacter sacchari, 94% C1: Gemmatimonas aurantiaca, 90% end of ice cover period autumn Munti Yuhana (2003) summer early winter Most abundant bacteria present at beginning of ice-cover period depth (m) Bands, closest known-species, similarity D12: Aquaspirillum delicatum, 97% D11: Aminomonas aminovorus, 94% D10: Bordetella avium, 97% D9: Aquaspirillum delicatum, 97% D8: Aquaspirillum delicatum, 97% D7: Polynucleobacter necessarius, 97% D6: Rhodoferax ferrireducens, 98% D5: Frankia sp., 91% D4: Leptothrix cholodnii, 97% D3: Sporichtya polymorpha, 92% D2: Frankia sp., 97% Munti Yuhana (2003) D1: Gemmatimonas aurantiaca, 90% end of ice cover period summer autumn early winter 114

58 PCR-RFLP profiles of the clones bp M M M: 100 bp Ladder 115 The kind of bacteria present in Jöri lake XIII 39.3 % 39.3 % 6.0 % 2.0 % 13.0 % 116

59 Diversity of Achaea clones in lake Joeri XIII and similarity values with nearest relatives 117 Enumeration of the microbial community composition in the water column of Lake Jöri XIII by FISH analysis. Microbial abundance (% DAPI counts) m, 27June m, 27 June m, 27 June m, 09 Sept m, 09 Sept m, 09 Sept m, 01 Oct m, 01 Oct m, 01 Oct m, 05 Dec m, 05 Dec m, 05 Dec Depth, sampling date ARCH915 ALF968 BET42a HGC69a SRB/DSS658 Other Eubacteria Percentage of hybridized cells in relation to total detected DAPI counts. Autofluorescent cells and NON EUB338 cells were substracted from the total number of fluorescent bacterial cells (excluding Archaea).!Other bacteria" refers to those bacterial cells (excluding Archaea) which hybridized to EUB338 but unaffiliated with either ALF968, Bet42a, HGC69 or SRB/DSS

60 Microbial diversity in high mountain lake ecosystems Bacteria Proteobacteria $, %, &, ', ( Actinobacteria and Bacteroidetes Cyanobacteria (organelles) Planctomycetes Acidobacteria Fibrobacteria Verrucomicrobia uncultured bacteria Novel Archaea uncultured Euryarchaeota Methanomicrobiales Crenarchaeota 119 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 120

61 Adaptation - Selection Hypothesis: constant ecosystem change and evolution through selection of niche specialists vs. niche generalists Only those will develop into higher population densities which are best adapted to the present conditions in the habitat; the others will remain alive but dormant until the conditions become more favorable for them. 121 How niche specialists respond to different conditions D C B A 122

62 Evolution is a game with frequently changing rules Fitness (probability of survival) Species B Species A Evolutionary rule 2 Evolutionary rule 1 Marshall CR. 2005, Annual Review Earth Planetary Sciences Fitness of A is better than fitness of B for the two presently valid evolutionary rules 1 and Population bloom after fall overturn 124

63 Peridinium umbonatum - fall bloom 125 Rapid bacterial degradation of Peridinium umbonatum fall bloom 126

64 Ecosystem concept to study the evolution of microbial community changes Physical and chemical determinants regulate the selection of communities with the phenotypically fittests organisms 127 but the fitness traits of B might become useful again if the evolutionary rules (i.e. habitat conditions) change Fitness Environmental rule 2 Environmental rule 1 Niklas KJ Computer models of early land plant evolution. Ann. Rev. Earth Planet. Sci. 32:47 66 Expected diversity = Number of roughnesses in the landscape 128

65 The roughness of the evolutionary landscape increases with the number of needs to adapt to changing conditions Diversity and disparity increase while organisms colonize the evolutionary landscape under fluctuating conditions 129 Niklas KJ Computer models of early land plant evolution. Ann. Rev. Earth Planet. Sci. 32:47 66 Definition of interactions in an ecosystem 130

66 Predator - prey interaction between protozoa and bacteria & archaea The predator population X 2 feeds exclusively on the prey population X1 In the absence of predators the prey populations grow with the rate a In the absence of prey the predator populations diminish with the rate b The number of ingested prey organisms at any time is proportional to the number of predators and the number of available prey The rate of decrease of prey through ingestion by predators is c The rate of increase of predators through ingestion of prey is d The interacting system can be described as dx 1 dt dx 2 dt = a X 1! c X 1 X 2 = d X 1 X 2! b X 2 Default values: a = 0.1 b = 0.05 c = d = Initial populations (t=0): X 1 = organisms ml -1 X 2 = organisms ml A 1:1 predator-prey interaction model Predator-prey oscillations Prey yellow Predator purple X-Y-Plot: X-axes: prey, Y-axes predator 132

67 The 2:1 predator-prey interaction model An additional predator is introduced which feeds on the same prey dx 1 /dt = a X 1 - b 12 X 1 X 2 - b 13 X 1 X 3 dx 2 /dt = b 21 X 1 X 2 - a 2 X 2 dx 3 /dt = b 31 X 1 X 3 - a 3 X 3 X 1 = prey (yellow), X 2 = predator a (blue), X 3 = predator b (purple) How will the model look if the smaller cililate X 3 is not only a predator for the bacterial prey X 1 but also a prey for the larger ciliate X 2? 133 Modeling population fluctuations dx1/dt = a1 X1 - a12 X1 X2 -a11 X12 (1a) dx2/dt = a2 X2 - a21 X1 X2 -a22 X22 (1b) Growth rates a are regulated by environmental determinants A and B a1 = a1a A*1 + a1b B*1 (2a) a2 = a2a A*2 + a2b B*2 (2b) aij = Impact of environmental determinant J to population i (i = 1,2; J = A,B) Ji,min, Ji,max= Extent of impact of environmental determinant J to population i (i = 1,2; J = A,B) J*i = max(0, min [1, (J - Ji,min)/(Ji,max - Ji,min) ] ), i = 1, 2; J = A, B A*1= max(0, min [1, (A - A1,min)/(A1,max - A1,min) ] ) 134

68 Simulink model 135 Population fluctutions with n populations and m determinants dx1/dt = a1 X1 - a12 X1 X2 - a13 X1 X3 - a14 X1 X4 -a11 X12 dx2/dt = a2 X2 - a21 X1 X2 - a23 X1 X3 - a24 X1 X4 -a22 X22 dx3/dt = a3 X3 - a31 X1 X3 - a32 X2 X3 - a34 X3 X4 -a33 X32 dx4/dt = a4 X4 - a41 X1 X4 - a42 X2 X4 - a43 X3 X4 -a44 X22 a1 = a1a A*1 + a1b B*1 + a1c C*1 + a1d D*1 a2 = a2a A*2 + a2b B*2 + a2c C*2 + a2d D*2 a3 = a3a A*3 + a3b B*3 + a3c C*3 + a3d D*3 a4 = a4a A*4 + a4b B*4 + a4c C*4 + a4d D*4 136

69 Simulink model for 4 populations and 4 determinants 137 Example: 4 populations with time variable determinants 138

70 Evolution to complexity 139 Lotka-Volterra-like competition model $ x i (t + 1) = x i (t)exp r! % & n # j=1 ' b ij x j (t) + " i (t) ( ) x = population size, number of species t = time r = intrinsic rate of increase b i j = competitive effects of species j on species i ( = environmental, unexplained variation = random variable i = species i j = species j n = n species involved A.R. Ives and S.R. Carpenter (2007) Science 317,

71 Research questions - contents of presentation Introduction to the Joeri lakes as high-mountain aquatic habitats Microbial life-styles at low nutrient concentrations Ecological determinants in cold high-mountain habitats Erosion particles act as nutrient scavengers Can erosion minerals be nutrients? Coupled iron, manganese and phosphorus cycles in Jöri Lake XIII Can particle bound chemicals be used as nutrients? The atmosphere as source for nutrients and microbes Colonization of remote habitats Regulation of community diversity Why is microbial diversity so high in Jöri lake XIII? 141