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Water and Carbon, Oceanic Oceans contain around 1.3 billion km cubed of…

- - - - Cloud formation
        Clouds are also unevenly distributed, driven by the global atmospheric circulation model which identifies latitudinal zones of rising and falling air.
        
        Equator: high temperatures result in high levels of evaporation. Warm moist air rises and cold and condenses to form towering banks of cloud and heavy rainfall in a low pressure, Inter Tropical Convergence Zone. This moves north and south seasonally.
        
        Mid latitudes are driven by the convergence of warm air from the Tropics and cold air from the Arctic. The boundary of these - the polar front- results in rising air and cloud formation , with the jet stream driving these unstable weather systems across, establishing the largely changeable condition experienced in the UK.
        
        Can occur on a more localised scale such as the formation of thunderstorms .
    - - Infiltration
        The movement of water into the soil.
      - Throughflow
        Water is transferred through the soil under the force of gravity towards rivers and streams.
      - Percolation
        Some water enters rocks below the soil though percolation, some rocks are impervious,; do not let water enter. Permeable rocks can be pervious or porous, allowing water through pores, or faults and joints.
      - Groundwater flow
        Water reaches impermeable bedrock below ground it flows over the surface of the rock.
      - Runoff
        When the soil is saturated, surface run off occurss.
    - - Positive feedback example: Rising sea levels destabilise ice shelves, triggering calving and further melting.
    - - Deforestation reduces interception and infiltration, overland flow increases.
      - Intense rainfall increases the amount of rainfall reaching the ground increasing the magnitude of stores.
      - Urbanisation impermeable surfaces reduce infiltration.
        Drainage systems quickly take the water to nearby river channels.
      - Irrigation in farming increases amount of water in the ground.
        Ditches in the land encouargage water to flow quickly to river channels.
      - Seasonal changes mean winter snowfalls and frozen ground interrupt the water transfers.
  - - - Over 30% of all freshwater is sorted in rocks deep underground in reservoirs called aquifers. These are crucial for the sustenance of civilisations.
        They most commonly form in rocks such as chalk and sandstone which are porous and permeable.
        They are either filled directly by breaks in the ground, or drain through the overlying soil.
        100-200 years shallow
        10,000 years deep
      - The upper level of saturated rock is called the water table which rises and falls in response to groundwater flow, water abstraction or recharge. ,
        A state of equilibrium is needed throguh careful management.
      - Fossil aquifers exist in the deserts of Africa, the Middle East, and Australia thousands fo years ago when these regions were much wetter.
        They are being exploited beyond sustainability.
        Saline aquifers exist if seawater has infiltrated, often through over abstraction.
  - - - The Role of vegetation
        Most drainage basins are clothed by one or more types of vegetation that will to some extent intercept precipitation.
      - A study of similar-sized upland catchments of the River Severn (67.5% of forest) and the River Wye (1.2% of forest) provided ointeresrtign comparative data on the role of forest interception in reducing runoff. having received the same amount of rainfall during he study period, the Severn catchment ‘lost’ some 38% of the total precipitation compared with just 17% of the Wye. The clear inference is that forest cover has an important impact in the drainage basin.
    - - The River Wye
        5th longest river in the UK.
        
        Rich in wildlife
        
        Upper basin characterised by steep slopes, acidic soils, grassland, cleared forestry to make way for sheep grazing and pasture. (Reduced interception, encourage overland flow)
        
        Ditches dug to make land productive has increased water transfer to river.
        
        Upper basin are impermeable rock such as mudstones, shales and grits. Southwards it flows over sandstone, cutting across a limestone gorge.
        -This means that groundwater flow is limited , soils quickly become saturated.
        
        Hereford often floods downstream
        
        Rainfall totals are highest in the western upland parts of the basin wjith higher temperatures and evaporatiranspiration occur in the east.
  - - - Circular drainage basins = more flashy
        Each point of the drainage basin is equidistant.
      - Steeper drainage basins = more flashy
        Water flows more quickly as overland flow or Throughflow.
      - Many surface streams = more flashy
        Acting tributaries so all the water arrives at the same time.
      - Prior saturation by antecedent rainfall = more flashy
        Infiltration capacity has been reached, overland flow is the fastest transfer.
      - Impermeable rock type = more flashy
        More overland flow, same for surfaces baked by prolonged sun, or frozen surfaces
      - Volume and intensity of precipitation = more flashy
        Lot of water entering in short period of time results in higher discharge. Lag time is greater for snow.
      - Less vegetation = more flashy
        Vegetation intercepts the precipitation
    - - Urbanisation = more flashy
        Impermeable surfaces built on floodplains, systems designed to move water away from human activity.
        
        Area of vegetation oequivalent to 300ha/year between 1998 and 2006 in London was lost as people opted for paved driveways opposed to front gardens.
      - Deforestation = more flashy
        Reduces interception rates. Lack of roots reduces the infiltration rate. Increases erosion of soil so channels increase sedimentation, reducing river capacity.
      - Agricultural Practice = more flashy
        Animal grazing can compact soils which lead to overland flows.
        Irrigation increases the water in a drainage basin.
        
        Ploughing and grass crops increase infiltration which subdues hydrographs- enhanced by contour plouhging creating furrows acting as small stream channels.
    - - Time between peak rainfall and peak discharge is called lag time.
- - - - The Carbon Budget
        Data to describe the amount of carbon that is stored and transferred.
        carbon transfers are extremely active as carbon constantly flows back and forth between the atmosphere and the land.
        
        Impact on land
        
        More intensive agriculture
        
        Land is warmed up increasing growing seasons, and increases the rate of decay.
        
        Impact on oceans
        
        Ocean acidification
        Dissolving carbon dioxide in the ocean creates carbonic acid .
        
        Carbonic acid reacts with carbonate ions which animals like coral and planktonic species use to create their shells as it reacts to make bicarbonate.
        
        Coral reefs provide food and livelihood security for 500 million people.
        
        Ocean warming
        
        Decrease abundance of phytoplankton. However an increase in CO2 may increase growth by fertilising those few species of phytoplankton which take CO2 directly from the water.
        
        Melting sea ice
        
        Highly reflective ice is replaced by more heat absorbent water, absororbing more sunlight, exacerbating the process which caused it to melt in the first place.
        
        Sea ice provides unique habitat for algae growth.
        
        Increased ocean salinity
        
        Increased freshwater reaching the oceans.
        Linked to possible slowing down of oceanic circulation in NE Atlantic which would impact NW Europe’s climate.
        
        Sea level rise
        
        Melting sea ice and thermal expansion.
      - Impact of the carbon cycle
        Most important is release of carbon dioxide and methan into the atmosphere.
        They absorb long-wave radiation from the Earth and warming lower atmosphere enabling life to exist on earth (greenhouse effect)
        however, increased concentration of these gases makes the greenhouse effect more effective, why global temperatures have increase 0.8 degrees since 1880.
  - - - Photosynthesis: use of light energy to convert CO2 to glucose, oxygen is released
    - - Terrestrial or biological sequestration
        
        Use of plants.
      - Geological sequestration
        
        Carbon captured at source, then injected underground in liquid form.
        Ocean capable of absorbing much more additional carbon that terrestrial systems. Once in deep ocean, it is in a circulation system for thousands of years, when only it reaches the seabed does it become part of the Earth’s geological system.
    - - However,, conversion of sulphur dioxide released to sulphuric acid forms fine droplets which increase solar radiation reflection.
  - - - Impact of warm conditions:
        Melting of permafrost in tundra regions (Siberia, Russia)
        Wildifires: more by lightning events and human deliberation. Can turn forests from carbon sinks into carbon sources.
      - Impacts of cold conditions:
        cold eater can hold more carbon, so weathering is more active.
        Difference in forest coverage .
        Deconomposers are less effective
        Less water flowed in oceans so less sediment transfer alone rivers, less build up on ocean floors.
        Frozen soils.
  - - - Deforestation
        Trees are removed, for commercial farming, timber harvesting and firewood.
        Concentrated in tropical regions ,a ccounts for 20% of all CO2 emissions globally.
        Naturally, they die and decompose very slowly, where new vegetation grows overtime compensating for that released by the dead tree.
        Combustion means that carbon is released immediately.
        Significant because these cosy stems are limited to very specific parts of the world.
      - Urbanisation
        Important stores are replaced or covered up.
        Urban areas occupy 2% of the total land area, but 97% of all anthropogenic emissions.
        Transport, development of industry, cement production.
- - - - Water cycle feedback loop:
        
        Ice reflects radiation from the sun so less heat absorbed on surface.
        
        Arctic ice retreats with less reflection.
        
        Water is exposed and heated
        
        Affects the magnitude of water transfers between land, ocean and atmosphere.
      - Carbon cycle feedback loop:
        
        Warmer temperatures in the Arctic increased the growing season for plants increasing absorption from photosynthesis.
        
        Melted the permafrost particularly in Siberia.Organic matter trapped in the frozen ground act as an improtant carbon store. As oxygen is introduced, the permafrost starts to decompose, the bacteria involved releases carbon dioxide.
        currently, the Arctic is a net carbon store, but this could change.
      - Water and carbon feedback loop:
        Phytoplankton us energy from the sun, with CO2 to photosynthesise.
        they are primary producers in aquatic ecosystems.
        marine phytoplankton release dimethylsulphide that may promote the formation of clouds.
        More phytoplankton associated with warmer temperatures and more sunshine could therefore lead to an increase in cloudiness and global cooling. But then, less sunshine, cooler earth, less phytoplankton.
        (Negative feedback)