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Microbial ecology

VL 5 Limnic habitats

Bert Engelen engelen@icbm.de

www.icbm.de/pmbio

Standing water:Lakes, ponds, swamps, highmoors

Flowing water:Springs, ditches, rivers

Limnology: Study of fresh water environmentsComprise biology, chemistry and physics

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- High specific heat :High amount of energy necessary to change water temperature

- High latent heat of fusion :High amount of energy necessary to change phase

- Highest latent heat of evaporation :Most of the light energy (sun) is used for evaporation

- Anomaly of density :Highest density at 4˚C

- Low thermal conductivity :Heat is mainly transported by motion of the water

Other important physical features:Solubility of gases decrease with temperature and pressure (Henry’s law).

Unique thermic properties of water

Covers about 2% of Earths surface

Less deep, less volume than the Ocean

Not connected to each other

Higher diversity with regard to physical,chemical and biological parameters

Salt content (Except some miniral springs)Inland waters < 0.05% (Ocean 3.5%)Anions: CO3

2- und HCO32-

Cations: Ca2+, Mg2+, Na+

Nitrogen (N), phosphor (P) und iron (Fe)mostly in very low concentrations

Limnic habitats

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Standing water: Lakes

Formation of gradients and different mixing-patterns (stratified lakes)

Small size => enhanced impact of terrestrial and sediment input

Higher productivity and sediment accumulation than in the marine habitate(per area and volume)

Strong climatic influences

Minor influence on biogeochemical cycles

Often young (post glacial)

Major influence on terrestrial life

Abbildung aus: www.waterquality.de

Different types of lakes

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(Odum ‘Ökologie’)

Ecological guildes in standing waters

Euphotic zone

(Odum ‘Ökologie’)

Primary producers in standing and slow flowing waters

Plants with floating leaves

Filamentousalgae (8+9)

Phytoplankton

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Stratified lakes

Oligotrophic and eutrophic lakes

Abb

. aus

Ha

fne

r und

Phi

lipp,

198

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EutrophicOligotrophic

Depth deep shallowEpil./Hypolimnion <= 1 > 1Primary production

mg C m-2 d-1 50 - 300 ≈ 1000Algal biomass

mg C l-1 0.02 - 0.1 > 0.3µg Chl a l-1 0.3 - 3 10 - 500

Total-Pµg l-1 < 10 > 30

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Light radiation decrease with depth

Light heat up upper layers

Turbulences of the upper water bodyresults in equal heat distribution

Distribution of light and temperature in a lake

(Lam

per

t un

dS

om

mer

‘Lim

noök

olo

gie’

)

Winter stagnation

Winter stagnation caused by ice cover (density anomaly)

Physico-chemical structure of stratified lakes

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Spring circulation

Spring circulation after disappearanceof density and temperature gradients

Physico-chemical structure of stratified lakes

Summer stagnation

Solar radiation => Light gradient => Temperature gradient

Physico-chemical structure of stratified lakes

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Epilimnion turbulently mixed (Eddy-Diffusion)

Density gradient forms a mixing barrier within the metalimnion

Accumulation of POC (detritus), P, Fe2+, NH4+ within the hypolimnion and the sediment

Formation of chemical gradients via microbial activ ity

Elektron acceptors are consumed in order of the respective redoxpotential

Consumption of O2 => anoxic conditions rise up from the sediment

Gradients of NO3-, NH4

+, CH4, SO42-, H2S, Pi, Fe2+, exiting at oxycline

Summer stagnation

Physico-chemical structure of stratified lakes

Modified after Wetzel

Algae, Cyanobacteria

Protozoa, Copepodes, Fish

Metalimnion

Bacterial remineralization

Sediment, anocix sludge

CH4 H2S CO2 minerals

Purple and Green Sulfurbacteria

CO2 minerals

Primary productionoxygenic photosynthesis

Secondary productionDegradation & recycling

Secondary primary productionanoxygenic photosynthesis

Anaerobic degradationFermentation, sulfate

reduction, methanogenesis

Vertical zonation in an eutrophic lake

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Allochtoneus DOC, POC Discharge DOC, POC

CO2 HCO3

Littoral flora, phytoplanktonPhototrophs and chemolithotrophs

CO2 CH4

Aerobic heterotrophs

Methylotrophs

Anaerobic degradationHeterotrophic fermenters

CO2

Org. acids

CH4

H2

Methanogens

Sedimentation

Simplified carbon cycle of a lake

Modified after Wetzel

Autumn circulation

Autumn circulation afterdisappearance

of temperature gradient

Physico-chemical structure of stratified lakes

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(Odum ‘Ökologie’)

Seasonal progression of phytoplankton in a standing water (temperate climate)

Phototrophic bacteria

Why am I not a phototroph ?

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Oxigenic phototrophic bacteria

Cyanobacteria

Abb

.: S

chle

gel,

1992

Single cells:

Gloeothece

Colony forming:

Dermocarpa

Filamentous:

Oscillatoria

Filamentousheterocystic:

Anabena

Filamentousbranched:

Fischerella

Purple non-sulfur bacteriaRhodospirillaceae

Green sulfur bacteriaChlorobiaceae

Phototrophic ArchaeaHeliobacter

Purple sulfur bacteriaChromatiaceae

Abb

.: S

chle

gel,

1985

Anoxigenic phototrophic bacteria

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Light attenuation:

- Reflection at the surface of the water (3-30 %)

- Absorption water itself, dissolved organic compounds,photosynthetic pigments (colour of the water)

- Deflection at particles (elongation of the wave length)

Decrease of phosyntheticallyusable radiation (400-700 nm)

Color λλλλ Abs. lightt (nm) (% m -1)

Infrared 800 85Red 720 65Yellow 565 4Green 504 1Blue 473 0.5 Purple 408 1UV 365 4

Light in aquatic systems decreases with depth!

Abb

.: S

chle

gel,

1992

Abb.: Perry & Staly, 1997

Absorption spectra of different phototrophic bacteria

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Abb

ildun

g au

s: R

hei

nhei

mer

, 19

85

(ver

änd

ert)

Lake Plußsee,

Osthostein

(Oktober 1964)

Vertical distribution of microorganisms in a stratified lake

Ecophys-course 2002

Sergei Winogradsky (1856 – 1953)

Winogradsky columns

Abb

.: S

chle

gel,

1992

Enrichment ofRodospirillaceae

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Halophilic phototrophs

A saltern in South africa

Staining of water byphotosynthesis pigments(Bacterio-rhodopsin)

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Famous microbiologistson vacation

Sampling asaline in Puerto Rico

10 µm

Water from thesaline

Colonies of phototrophic Archaea(Halobacteria)

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Acidic mining-lakes

Remediation:

Recycling of acid-forming sulfate to sulfite in form of pyrite (precipitation)

Problem:

Oxygen and oxygen-rich rain led to an oxidation of pyrite in the subsurface:

2FeS2 + 7O2 +2H2O = 2Fe 2+ + 4SO4 2- + 4H+

Example Restloch 111Lake volume 500.000 m3

Sulfate 1.200 mg/L pH 2.5

Fe III +organic substrate

iron reduction Fe II

H+

Remediation

sulfate +organic substrate

H2S

H+

sulfate reduction

H2S +FeII FeS, FeS2

sediment

Concept of remediation

Variants:E1 controlE2 Straw + Carbokalk (2,4 mM TOC)E3 Straw + Carbokalk (24 mM TOC)E4 Straw + Ethanol (2,4 mM TOC)Straw 35 kg each

Abb

ildu

ng:

Ines

Pö

hler

, 20

02

(ve

ränd

ert)

Experimental design

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- Current represent regulating and limiting factor

- Significant exchange of nutrients between land and water

- Constant oxygen content, only minor zoning of temperature and chemical conditions

Features of flowing waters

Horizontal zoning along rivers and ditches

comparable to vertical distribution in standing waters

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Self-purification of flowing waters

Input of organic material and salt

Succession of key-organisms(Saprobia tables)

Increasing numbers of Organisms1. Bacteria2. Protozoa

Increase of O2-consumption

MineralisationRelease of phospate and nitrogen compounds

Increasing growth of Algae

Normalisation to initial situation

Digestion tower

Waste water treatment plants (e.g. Schwerte)

Clarifier

Aeration tank

Primary clarifier

Sand catcher

Rack

Rain clarifier

Operationalbuilding

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The waste water treatment plant in Oldenburg(Wehdestraße in Donnerschwee)

Sewage mechanical and biological clearing Hunte

Raw sludge Fouling and methane exploitation Agriculture

Heat Energy (powerplant)

Municipal sewage:Effluent from Small companiesIndustry Agriculture Water from rainfalls

Dimensioned for 210.000 population equivalents => 5 .000 m³ h -1

Cleaning capacity per day:Carbon (BSB5) 98 % = 10.500 kg Phosphorous (Ptot.) 95 % = 300 kg Nitrogenic compounds (Ntot.) 88 % = 1.800 kg

Bestimmung von Inhaltsstoffen des Abwassers

Definition:

Der BSB5 ist die Menge Sauerstoff in mg/l, die für den biologischen Abbau

im Dunklen bei 20°C nach 5 Tagen verbraucht worden ist.

Definition:

Der CSB ist die Menge Sauerstoff in mg/l, die für die vollständige Oxidation

eines Substrates verbraucht worden ist.

Bei kommunalen Abwässern: Verhältnis BSB : CSB = 1,5 - 2

Erfassung von schwer abbaubaren Substraten (CSB):

Naturstoffe (Bsp.: Lignin, Huminstoffe) und Xenobiotika

Erfassung von leicht abbaubaren Substraten (BSB 5):

Zucker, Proteine und Aminosäuren, org. Säuren, Fettsäuren, Lipide

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BSB5 Bestimmung des Abwassers

Rechenbeispiel:

Bei der Veratmung von 1 Mol Glucose werden 6 Mole Sauerstoff verbraucht:

1g Glucose erfordert 1,07 g O 2

C6H12O6 + 6 O2 6 CO2 + 6 H2O

Verbrauch von O2 bei oxidierten Substraten < 1g O2/g Substrat

bei reduzierten Substraten > 1g O2/g Substrat

Essigsäure (0,94); Proteine (1,46); Buttersäure (1,82); Methan (4)

Einige BSB 5 Werte:

industrielle Tierproduktion (Gülle):

Molkereien und Brauereien:

Kommunales Abwasser:

biologisch gereinigtes Abwasser:

reines Flußwasser:

10 000 – 25 000 mg/l

500 – 2 000 mg/l

200 – 300 mg/l

15 – 40 mg/l

1 – 3 mg/l