Carbon And Water Cycle-CS Flashcards
Carbon cycle on the tropical rainforest:
-during photosynthesis, a plant absorbs carbon dioxide from the atmosphere. Carbon is used to form the organic body of the plant, while oxygen is released back into the atmosphere
-when a plant respires dies or burns, the carbon within the plant is released
-the carbon gets released into the ground where it stored sediment underneath water
- the sediment becomes fossil fuels over millions of years
Rainforest Carbon storage and flows:
-the soil carbon store averages around 100 tons per hectare
-warm, humid conditions leads to the short rapid decomposition of dead organic matter and the quick release of CO2
-as a result, the letter store is proportionately small in this biome
- heavy rainfall means that soils are leeched and only retain limited amounts of organic carbon in the form of hummus
Deforestation in the Amazon
- oil palm cultivation takes place at the expense of tropical rainforest cover
-Clearance of tropical forest for settlement and agriculture has led to increase carbon emissions
-major crops such as Soya beans are grown on old rainforest soils in Brazil. The biomass of soya crop cover is 2.7 tons per hectare compared with 180 x per hectare for Virgin rainforest
Aforestaion in the Amazon
-new trees act as carbon sinks and can help with climate change mitigation
-UK forestry commission which was established in 1919 to increase timber supplies
- In recent years, the forestry commission has used sequestration as justification
- New mono culture of commercial trees such as Coniferous plantations in the UK can increase carbon storage if it replaces grassland
- however, plantations store less carbon than natural rainforest because monoculture forest lack biodiversity and provides few habitats for other species
carbon offsetting is a weight of compensating for your emissions by funding and equivalent carbon dioxide saving somewhere
Soil and wind erosion in the Amazon
- In the Great plains wind erosion striped the topsoil from 65 hectares of over cultivated land leading to an enormous loss of soil carbon storage capacity
- positive changes in carbon storage result from use of manual and composite plant debris and bio soils from sewage to agricultural soils
Carbon-Amazon
-UFZ estimated that the Amazon stored 76 billion tons of carbon in 2019.
-Studies have shown that these forests have been increasing in above-ground biomass by 0.3-0.5 per cent per year and that the rising productivity of tropical forests is due to increasing CO2 concentrations in the atmosphere. The resulting negative feedback seems to offset any rising atmospheric levels of CO
-It appears that an increase in atmospheric CO led to a growth spurt for the Amazon basin’s trees, overtime, however, the growth stimulation feeds through the system, causing trees to live faster and die younger.
-This has led to a surge in the rate of trees that are dying across the Amazon.
Water in the Amazon
- Up to half of rainfall may never reach the ground, It is intercepted by the forest canopy and re-evaporated into the atmosphere.
- Additional water evaporates from the ground and rivers or is released into the atmosphere by transpiration from plant leaves
Climate change in the Amazon
- a mean temperature increase of 0.26°C every ten years since the mid-1970s and predict that by the year 2050, temperatures in the Amazon will increase by 2-3°C.
-Amazonia experienced falling amounts of rainfall between the 1920s and the 1970s but since then it appears there has been no significant change.
Vegetation changes in the Amazon
-There has been a massive net loss of forests in the Amazon Basin.
-WWF estimates that 20 percent of the Amazon forest has already been lost and that will rise to 27 per cent by 2030 if the current rate of deforestation continues.
-Some species are limited by their tolerance to temperature change, drought and seasonality.
- Climate change can affect species sustainability by directly altering the conditions needed and unusually high to grow and survive, Droughts temperatures in the Amazon in recent years may also be playing a role in killing millions of trees although the tree mortality increases began well before an intense drought in 2005.
Soil changes in the Amazon
-Amazonian soils contain from 4 to 9 kg of carbon in the upper 50 cm of the soil layer, while pasturelands contain only about 1 kg/m².
-When forests are cleared and burned, 30-60 per cent of the carbon is lost to the atmosphere, unburned vegetation decays and is lost within ten years.
-The soil fungi and bacteria that used to recycle the dead vegetation die off When forest clearance first occurs, the soils are exposed to the heavy tropical rainfall. -This rapidly washes away the topsoil and attacks the deep weathered layer below.
-Most of the soil is washed into rivers before the forest clearance has caused a reduction in the rainfall
Tell me about the 1976 drought
Background: 1975+1976 where exceptionally hot and dry
•summer of 1976 went 36 days without rain
Causes:
•low rainfall caused by a northwards shift of jet stream which persisted for 18 months
•The weather systems that generate frontal rain follow the jet stream, so much of the UK’s normal expected rainfall was delivered northwards throughout much of 1975+76
Coping techniques: •a public campaign was set up to promote ‘bath with friends’
Positives: •Insect-feeding birds were well supplied with food as warmth living insects thrived
Negatives: •farmers struggled- The grass stopped growing, then browned off so that farmers had to feed barley straw and hay to hungry stock, while providing thirsty animals with water became increasingly nightmarish.
Aral sea -water store changes
- Global hydrological stores change in size over time by both human and physical factors
- for instance, water stores in the aral sea has declined since a 1990s
-was once the fourth largest lake in the world
-sources of water are precipitation and snow melt from far away Mountains
Causes:
- Soviet Union diverted two major rivers to irrigate farmland from 1960s so started to decline and by 2014 most of the lake had dried up
effects: fisheries decline
solutions: 2015 a dam was constructed to increase flows to the southern basin -water levels in the North started to increase
-seasonal rains wasn’t enough to refill the sea
-the lake is only 1/10 of its original size
Ogallala aquifer, USA
•is a giant underground sponge, made up of gravel, silt, clay and sand
•all the water is contained in the crevices of the sponge
•Groundwater levels have dropped 150 feet, forcing farmers to abandon their wells
Causes:high plains farmers were unaware a generation ago that the dilemma was already unfolding. Early 1950s everyone believed the water was inexhaustible.
•overuse
•yearly groundwater withdrawals quintupled. between 1949 and 1974
Solutions:
•evapotranspiration
•plants can communicate with high-tech irrigation systems
•researches are designing equipment that uses lasers to measure the turbulence caused by heat waves above crops. The more turbulence, the more water plants need
•this equipment will estimate daily evapotranspiration rates on a regional scale.
•The Ogallala initiative
-its a us department of agriculture project that funds studies designed to make the agricultural industry more sustainable
-an annual $3.6 m supports the research tanging from irrigation techniques and precipitation management
•alternative uses of farms
-grasslands would be grazed by cattle- many farmers look to turn their fields into grasslands instead of planting crops which uses more water
Northan Pennines background
-has blocked over 1000 km of moorland drains since 2006
-once blocked, the ditches fill with water and begin to revegetate slowing restoring to the moorland vegetation
-lack of nutrients and oxygen, low temperature, high acidity and water logging forms peatlands
-Northern Pennines are a blanket bog which is a type of peat that is fed primarily by rainfall
-The common finding is that peatlands are the single most important soil type for carbon storage, containing more than half of total UK total soil carbon.
Restoration techniques in northan Pennines
-Fence. used to exclude factors that limit the recovery of vegetation on bare peat sites. This includes grazing, burning and vehicle traffic
-Heather brash. all of the bare peat is covered with heather brash. This prevents frost heave, the subsequent drying, erosion and the wind
-revegetation techniques• to encourage and speed up the re-vegetation of bare peat. These can include adding small amounts of fertiliser and moorand seed.
