L8 & 9 - Glacier Microbiology & Biogeochemistry Flashcards
Give 6 ways that we can use glacier microbiology work?
- Helps us understand how life evolved
- Predict how life might operate on other planets
- Understand snowball earth and past global glaciation life survival
- Understand extreme environments using biotechnology
- Find out how glacier melt impacts downstream systems
- Understand how organisms change glacial systems (albedo)
Until when were glaciers thought to be sterile?
~30 years ago
Give 2 pieces of evidence we have for glacial life
- Watermelon snow in the Alps
2. Chemical imbalances in meltwaters
What does life need to survive?
Water & Energy
What must be considered when looking at water in the cryosphere?
Thermal Regime
Microorganisms can extract nutrients from rock/debris – True or False
True
Where does life reside?
Primarily the supra and sub glacial environments but there is also some in the englacial environment
What species of algae is present on snow and what colour pigmentation does it have?
Chlorophota chlamydomonas
Green & Pink/Red
What do the pigments on snow algae protect them against?
UV and Freeze-Thaw
What impact do the pigments on snow algae have on albedo?
It lowers it
What are ice algae resistant to?
Low Temperatures
What does ice algae look like?
Dirt
What does ice algae do to the ice sheet surface?
It causes a Darkening
What is a Cryoconite Hole?
A self-contained, unique habitat made up of ice, water and sediment along with windblown or avalanched debris and microorganisms
What role does the Ice Lid play for a Cryoconite Hole?
It provides protection from hostile conditions and creates an isolated stable environment, in which light can still penetrate
Give 4 points about Antarctic Cyroconite Holes
- Stable Community
- May be isolated from the drainage system for decades
- pH 11!
- May be sealed off from the atmosphere for years at a time
Give 3 points about Arctic Cyroconite Holes
- Ice lids melt out and the hole remains stable during flushing
- Remain connected to the drainage system and the atmosphere
- Sediments and microbes bind to form granules from EPS
How can supraglacial channels and ponds host life?
Debris = micro-organisms and nutrients which = energy which = life
What is an EPS?
Extra Polymer Substance
Supraglacial channels and ponds are well studied - True or False?
False
What are the main sources of water and energy in the subglacial environment?
Debris, Lakes and Channels
At the glacier bed, there is a lot of debris and minimal light, what are the 2 main types of specialist organisms that live there?
- Chemoautotrophs
2. Chemolithoautotrophs
Where is there evidence of debris in climate records?
Debris bands in polar ice cores
Who found that there are active microbes at the bed that require electrons acceptors via REDOX reactions?
Skidmore et al., 2000
Give 6 energy sources in the subglacial environment
- REDOX Tower
- Ammonia (NH4)
- Pyrite (FeS2)
- Sulphate Reduction
- Methanogenesis and anaerobic methanogens
- Rock Crushing (Source of H+)
What 2 things help microorganisms in the subglacial environment?
- Summer Melt
2. Rock Grinding
What is Blood Falls and what may its research be helpful for?
A subglacial outflow with rusting processes and carbon cycling and microorganisms that have adapted to survive using the REDOX process. May be helpful on Europa
Where can the subglacial environment get nutrients from? (With Citation)
The surface and the rocks
Boetius et al., 2015
Give 3 facts about subglacial lakes
- There is liquid water at the bed of the ice sheets (up to 3-5km down)
- They are geothermal hotspots
- There are over 350 in Antarctica, with this number rising annually
How do subglacial lakes exist?
Ice at the bed is at the p.m.p due to a geothermal heat flux, there must be suitable topography which gives a depression allowing meltwater to collect and for ice to flow over the top. Insulation for the water acts as feedback mechanisms whilst sealing the lake off from the atmosphere. Temperature fusion pressure alters the p.m.p.
Is there liquid all year-round in subglacial lakes?
Yes
Give 2 methods of finding subglacial lakes
- Satellite Imagery
2. Sounding
What does a radar return of a subglacial look like?
It is flat
Who has studied Lake Vostok?
The Russians
Who has studied Lake Whillains?
The USA
Who has studied Lake Ellsworth?
The UK
How big was the ice core taken from Lake Vostok?
4km
What is the biggest subglacial lake under Antarctica?
Lake Vostok
What was the problem with the samples taken from Lake Vostok?
Contaminated by drill fluid and anti-freeze
Where does AI 1 occur?
In the embayment
Where does AI 2 occur?
In the open lake
How are microbes present in Lake Vostok?
From refrozen accretion ice
What is an inclusion?
A mineral particle to which dirt is attached and traded on refreezing
What is Meteoric Ice?
Refreezing onto ice above the lake
What is rate of accretion at Lake Vostok?
2-6cm/year
At what end of Lake Vostok is there accretion?
Southern End
Give 4 pieces of evidence for accretion ice
- Crystal Size
- No gas trapped between the crystals
- Isotopes
- High EC
What was found at Lake Whillains?
Cycle based use of ammonia from dead organisms and a diverse ecosystem
Why did the Lake Ellsworth study end with no samples?
Technical difficulties and a challenging environment
Give 2 methods of drilling cleanly and which is only good for geomicrobiology and not climate science
- Hot Water Drilling
2. UV Sterilised Water (not good for climate science)
Under which lake were fish found?
Lake Whillains
Where is life found in Englacial Habitats?
In the solute rich veins in between crystals
How have organisms in the glacial environment adapted?
Anti-freeze proteins and desiccation
Give 5 reasons why we are interested in glacial life?
- Climate Amplifier
- Ocean Fertilisers
- Ice Albedo Feedback
- Biotechnology
- Astrobiology
What must organisms in the englacial environment be adapted to?
Living without Oxygen
