Water and Carbon Cycles extra deets

How much of Earth's water is in oceans?

97%

How much of the Earth's surface is covered by oceans?

72%

How much of the world's oceans have been explored?

5%

What is the average pH of the oceans?

8.14

How has the average ocean pH changed?

It was 8.25, 250 years ago

Why has the ocean pH changed?

Atmospheric carbon increasing

What is the average ocean depth?

3,682 m

What size is an ice sheet?

Over 50,000 km2

How much ice sheet is in Greenland?

1.7 million km2

How much ice sheet is in Antarctica?

14 million km2

How much of Earth's freshwater ice on Earth is in Greenland and Antarctica?

99%

How big can ice streams get?

Up to 50 km wide and 2 km thick

If the Greenland ice sheet melted, how much would sea level rise?

6 m

If the Antarctic ice sheet melted, how much would sea level rise?

60 m

How big is an ice cap?

Smaller than 50,000 km2

What is Africa's only ice cap called?

Furtwangler Glacier on Kilimanjaro

How big is Africa's only ice cap?

60,000 km2 but melting rapidly

How many Himalayan glaciers form a reservoir?

15,000

What rivers are fed by Himalayan glaciers?

Indus, Ganges, Brahmaputra

What qualifies as permafrost?

Ground less than 0 degrees for at least 2 consecutive years

How thick can permafrost get?

1,500 m

How many major glacial periods have there been?

5

What is the Quaternary period?

Last 2.58 million years

In glacial periods how low was sea level?

120 m lower than today

How much of all water is in rivers?

0.0002%

How much river water is in the Amazon?

1/5

How does the Amazon's discharge compare to the other rivers?

Greater than next 7 largest rivers

How big is a lake?

Over 2 hectares (smaller - pond)

How many lakes does Canada have?

31,752

What is the largest lake?

Caspian Sea

How big is the largest lake?

78,200 km2

How old is the largest lake?

5.5 million years (ancient ocean)

What is the deepest lake?

Lake Baikal, Siberia

How deep is the deepest lake?

749 m avg depth

On what continents are there wetlands?

All but Antarctica

How much of the Arctic is covered by wetlands?

60%

How deep is groundwater?

Up to 4,000 m

What is an example of groundwater?

Borehole in Kola Peninsula, Northern Russia - hot mineralised water 13 km deep

What is the water table?

Depth where rock is saturated

What is an example of wetland?

Pantanal of South America - world's biggest freshwater wetland system

How much of Earth's water is drinking water?

0.3%

what happens to energy when water changes state?

either absorbed or released in form of latent heat

when does evaporation occur?

energy from solar radiation hits surface of water or land and causes water to change from liquid to gas

when does condensation occur?

when temp of air is reduced to dew point but volume remains constant

what is adiabatic cooling?

volume of air increases but no addition of heat

what are the 3 types of adiabatic cooling?

relief/orographic (hills)

frontal

convectional

how much rainfall is caught by a forest of needle-leaf trees?

22%

how much rainfall is caught by a forest of broad-leaf trees?

19%

what 3 things cause water to infiltrate?

gravity

capillary action

soil porosity

why does the infiltration rate decline rapidly in a storm in clay based soil?

clay absorbs moisture so clay particles expand, reducing size of pores

what is soil storage?

amount of water stored in soil

what is the soil storage of clay?

40-60%

what is the soil storage of fine sand?

20-45%

what is infiltration capacity?

the maximum rate at which rain can be absorbed by a soil (and it becomes saturated)

what feeds rivers in times of drought?

base-flow

what is an aquifer?

porous rock able to store vast amount of water

what is depression storage?

dips on ground storing water

drainage basin discharge equation

drainage basin discharge = precipitation +/- changes in storage

how can ploughing lead to flashier hydrographs?

contour ploughing (downslope) creates channels for water to run down into river

what is the river regime?

variability in river discharge throughout the course of a year in response to precipitation, temp, evapotranspiration and drainage basin characteristics

how are river regimes plotted?

discharge on y axis and months on x axis

what is the dominant source of fresh water in many areas of Europe?

groundwater

how is the water balance/budget graph plotted?

ET and precipitation on y axis and months on x axis

why does too much water abstraction cause groundwater degradation?

saltwater from sea intrudes

what is an example of saltwater intrusion?

Malta

has resorted to expensive desalination plans

why can sinking water tables also make rivers less reliable?

many river flows maintained by springs in dry seasons - these dry up if water tables fall

what is the main cause of groundwater exploitation?

irrigation

what is an example of groundwater exploitation leading to falling water tables?

Italy - Milan aquifer fallen 25-40 m in 80 years

where has groundwater been abstracted from in southern England?

South Downs/Chilterns - chalk aquifers

what is the impact of groundwater abstraction in southern England?

seasonal springs drying up, impacting stream systems - lack of fishing, tourism and recreation

when was water from the chalk aquifers below London over-exploited?

Industrial Revolution due to growth of brewing industry

how low did London water levels drop during the Industrial Revolution?

88 m

what is happening to the London water levels now?

recovering due to industry relocation

but rising water levels threaten underground system e.g. Tube

how much of tropical South America has been cleared to cattle pasture and agriculture?

10%

what are tiles?

networks of perforated tubes 60-120 cm below soil surface to remove excess water

originally made of clay pipes - now plastic

how do tiles work?

if water table is higher than tiles it flows into the pipes and drains away to bring it down to the level of the tiles

increases field productivity

what is controlled drainage?

water table kept high in off-season when crops not growing

what 8 human activities impact the water cycle?

cloud seeding

flood management

afforestation

dams and reservoirs

deforestation

urbanisation

climate change

agriculture

how does cloud seeding work?

condensation nuclei released into atmosphere - usually silver iodine particles

water vapour accumulates around until heavy enough to fall as raindrops

what is an example of cloud seeding?

Boise, Idaho

local farmers rely on snowmelt from mountains for irrigation - enlarging snowpack volume hoped to stabilise water supply

how has Houston's (Texas) population changed?

nearly doubled in 50 years

2 impacts of Houston urbanisation

loss of 100,000 ha of wetland and 7,000 homes built on floodplains

what is an example of deforestation impacting the water cycle?

Freetown, Sierra Leone

Aug 2017 mudslide from deforested Central Highlands killed 1,141 and exacerbated flooding

What is an example of flood management in Pickering, UK?

Slowing the flow

What flood management techniques are used in Pickering, UK?

Soil embankments, afforestation, wood debris in streams

impacts of flood management techniques in Pickering, UK

They increase interception, infiltration, water storage in tributaries, and improve river flow through town

what is an example of a dam and reservoir?

Grand Ethiopian Renaissance Dam - finished in 2020

where does the GERD's hydroelectricity go?

Ethiopian national grid

where does the GERD's water surplus go?

Sudan

why are Sudan and Egypt worried about the GERD?

reduced sediment supply - erosion, affects depositional features e.g. deltas

impacts farmers and ecology

how do tree roots help drainage?

create network of channels through which water can infiltrate

what is an example of afforestation?

county Leitrim, in north of Ireland

how has Ireland's forest cover changed?

1% 1900

11% now

why might Leitrim have planted the wrong type of tree?

Sitka spruce - evergreen so less decomposition and shallow roots so less infiltration

?% of the USA's irrigation groundwater comes from the ? aquifer

30% comes from Ogallala Aquifer

what has caused the Ogallala Aquifer's table to drop so much?

advances in automatic irrigation e.g. centre pivot method

how much has the Ogallala Aquifer dropped?

up to 150 ft in places

put these in order of carbon content

atmospheric CO2

permafrost

sedimentary rocks

oceans

living biomass

soils

sedimentary rocks

oceans

soils

permafrost

atmospheric CO2

living biomass

what is carbon transfer within the cycle measured as?

gigatonnes per year (GtC/year)

which ecosystem stores the most carbon? How much?

boreal forest 26% (e.g. in Russia)