Bob's stuff Flashcards
When is much of the arctic warming
Late winter and spring
What sort of soil is in the arctic?
Mostly organic soil- things aren’t broken down when they die because its too cold. Stores 25-50% of SOIL organic carbon
What can happen when the permafrost melts
Water logs can burst and get massive solifluction (foliage of water saturated soil down slope). Taking with it vast amounts of organic material (carbon) out to the arctic ocean
Active layer does melt in summer and it is becoming deeper
What is Arctic-HYDRA and what does it do
About the hydrology of the environment. Objective to understand biotic and abiotic controls of C fluxes in permafrost environments, with particular emphasis on the interface between water and C cycles, and on the implications for global radiative forcings (how much carbon we put back into the atmosphere from GG)
- interdisciplinary
Lots of C drains into arctic oceans and it is hard to figure out how much because a lot goes underground.
DOC
Dissolved organic carbon
Tea water, humid material
POC
Particulate organic carbon
Have to screen out PC when water is treated. Can take it out to make peat
Heterogeneity of Arctic Landscape
Bare bits, lakes, low lying filled with shrubs, trees a bit further down, wetland, canyons. Each bit of the landscape can respond differently to climate change - this is why we are interested in different spatial scales, from cm to 1000km
How is tundra characterised
By the presence of high albedo surfaces (snow, ice, and low tundra vegetation) because fo these attributes, tundra has a key role in moderating the global energy budget.
Permafrost feedbacks
Permafrost melting - more organic material respired - more c released - more global warming
What would happen with less snow
Even if less still distributed similarly. Still blown off some parts of landscape. Always blown into woods and forests and fills them up and so protects them. So less snow, would fill up forests then the rest blown onto landscape.
Depending on the topography of the landscape (slope, aspect of prevailing winds) probably means that factors of snow kept constant. Makes some predictions easier When a land type is filled it can only be filled once th rest will blow away.
Only would be effort if very little snow and regions didn’t fill anymore but this is unlikely
Why is snow important
If and for how long we have snow is important because ti determines plant growth. The period of fixing carbon could begin earlier if snow melts earlier. If it comes easier and we get more in winter could alter the environment in other ways
How could we measure the impact of snow
over winter
in different parts of the landscape (scrub, heath, sedge (poor fens), lichens
built snow fences- they slow the wind so causes snow to be dumped by them. Can build up different amounts of snow on the landscape and see how it effects them.
Soil probes and automatic weather stations
Took a camera, put it in a box with a solar panel. Takes 2 photos a day and recorded.
Can see spring arise in about 4/5 days. Autumn is short too. So moving these seasons would make a huge difference to the growing season (sun 24 hours a day in the growing season). Important to understand how seasons transition
could also measure snow depth and see what grows when its gone (lots of snow, shrub communities)
What do eddy flux towers do and how could they be involved in experiments
They measure photosynthesis. Air movement in XYZ and co2 conc. Eddys in the air. Some take atmosphere to the ground, others opposite. This machine measures CO2 conc and wind speed x10 per second. Can allow us to look at where air packet coming from and what the co2 concentration is. If coming from the ground in the summer it should have less co2 than when it went down bc photosynthesis.
In winter should be more because soil respiration happens.
But flux footprint depends which way the wind blows and how strong so moves.
Fetch is which bit of the landscape the tower sees at which point in time. Partly due to the height of the tower (bigger = more view). One in scotland can see the whole of scotland. So we can partition out which bit of the landscape produces what
Different % of gases from different parts of the landscape. Can measure net fixation or loss of C. so can get an average without having to measure each individual bit
willow beds become full of snow and often fix a lot of carbo
green lawns fix c all year long.
Sedge switches and gives out c in august. when it dries it gives out c
This helps us model better
How can chambers that measure gas help?
if we want to measure the movement of carbon in water with gas analyser measuring how much co2 comes out of water once water leaves the ground
put the box in the water with gas analyser measuring how much CO2 come out of the water once the water leaves the ground
What do V-notch wears do
measure the flow and the volume of H2O leaving, once this is known we can model for the whole landscape the c leaving via water
Can check how much co2 is gassing and so can calculate how much is released per day. Can measure gas flux from surface of water too
Isotopic signatures
tracing water through landscapes through isotopes. Picking up the isotopes in water that change as water moves through the environment , with this we can infer where water has been
Look at the relationship between H and O. Look at the change and difference from standard mean oceanic water (value taken every year from a place in the ocean and this is the standard for the year)
heavy isotopes (eg O18 and deuterium (heavy H)) evaporate less readily
What is the global meteoric water line
if you look globally at precipitation you should find relationship between delta D and deltaO18 which falls on a certain line
if water is not meteoric (not from rainfall)then it is from the landscape. Lakes veer of meteoric line
when water evaporates from a lake then O16 evaporates first. the remaining water is enriched in O18
Rain is O16 enriched
Snow is O18???? enriched. Snow melt is O18 enriched
If you know the phases can look at the isotopes and plot them
In September the signature changes as no more snow is input, just have meteoric rain. Signature changes through the seasons
Dissolved inorganic carbon
in lower parts of landscape (with melted out permafrost) very high in CO2 that gases out to atmosphere. DOC is dissolved in water. Higher in lower regions because lots of freeze thaw action (which breaks down organic material and makes it v wet) it gets into water
Methane and the landscape
Anaerobic conditions produce methane. In the landscape in wetlands there will be methanogens that produce lots of ch4.
Where it is mesic in those parts of the landscape (not too wet or dry) have loads of methanotropes- organisms that take up methane and use it as an energy source. SO CH4 could be produced in hotspots around lakes but methanotropes exist. Even if they only take up relatively small amounts they are over thousands of kilometres. More of the land is mesic than not
So have to figure out the balances
if we dont put the right numbers into the calculation the answers could be way off
methane also dissolves in h2o flowing off landscape and can be oxidised to co2 or can as out itself as ch4
can get ebullition in water. when it is frozen the methane can bubble on the surface under the ice. if you piece a hole it is very flammable
what is cryoturbation
cryoturbation (frost churning) refers to the mixing of materials from various horizons of the soil down to the bedrock due to freezing and thawing.
lots of DOC, DIC, and CO2 (methane probably oxidised to co2)
What parts of the landscape is methane highest in
lake then polygon then stream
but polygon and stream very close
Polygonous landscapes very extensive and play a major role.
Carbon throughout the landscape
C in sims if respired goes into the atmosphere as co2 this is going to be enhanced by warming and drying (faster respiration) Normally recent carbon is respired from fixation but deeper soils (with lots of old C) may be melting
data suggesting older C is respired faster, old c has been out of the system for a long time
What can mass spec be used for
In hummock areas there is a deeper active layer. He got a syringe and put in a vacuum glass bottle and injected gas samples and they went to mass spec to work out the isotope and age of the C
using bomb peak of C in 1964 (atomic bomb testing, another for chernobyl disaster) can see this in records can use this to date
DOC 3% ancient (1000+) 37% pre-industrial (1000-1750) 40% post-industrial (1750-1950) 20% post-bomb (1950+)
CO2 1% is ancient 28% pre-industrial 45% post-industrial 26% post-bomb
We can alter models appropriately now we know these values
How should climate change affect the south of the boreal forest
we can see the treelike moving north. If CC having an equal effect in the N as S should see recruitment failure in S
Normally post-fire have successional period then go back to boreal forest, but evidence (from space) suggests this isnt happening
FIREFLIES is a project fire recovery and forest loss in SE Siberia. Looking for when and where recruitment failure occurs, what causes it and climatic feedback. Doing an experiment by lake baikal.
