GE1101E BIOSPHERE
BIOGEOGRAPHY
Features and processes
How soils and vegetation are generated
Anthropogenic impacts to the biosphere
BIOMES
inland tropical forests and mangroves
How are they managed in a singaporean context?
BIOSPHERE
Sum of all soils, biomes, flora and fauna
Interactions with other components of the Earth
Plants and animal distribution and patterns
ECOLOGY = relationships between organisms and their environments
Ecosystems = complex of many variables
complicated flows of energy and matter
an open system
biotic and abiotic components
Habitats = physical environments where species live
climate and topography
Ecological niches = specific functions for an organism in that ecosystem
COMPETITIVE EXCLUSION PRINCIPLE
Apex predator concept
TRANSFER OF ENERGY IS CRITICAL in ecosystems
NPP: total photosyn - total respir FOR A PLANT COMMUNITY
Photosyn, respir, transpir
Elemental processes through C, O, N, H20
PROCESSES
BIOTIC
ABIOTIC
Food chains and trophic levels
energy is transferred through consumption and decomposition
Loss of energy between trophic levels
Possible push towards vegan/vegetarianism
Energy flows can go both ways = TROPHIC CASCADE
Pri --> tertiary or VICE VERSA
Can affect phy geo in profound ways
Elements recycled in biosphere through gaseous or sedimentary cycles
C and O cycles linked by Photosyn and Respir
Mobile reservoir of C and O in atmosphere
Nitrogen cycle
Needed for protein makeup in plants
Lightning fuses N to soils
Bacteria fixes N to N03s and NH4s
Natural N vs human fertilizers
SOILS AND VEGETATION
Soils = unconsolidated regolith
50% mineral and solid matter
other half
1/4 air
1/4 humerus
1/4 water
Dynamic zone of interaction between rock and atmosphere
Medium for vegetation growth
Develop into horizons from interactions with air, organic matter, water, minerals
distinguished by colour
Different horizons = diff soil profiles
O horizon = ORGANIC MATERIAL
A horizon = Minerals + dark-coloured organic material, seed germination
Elluviation --> downward gravitational movement of material through soil layers
B horizon = Where material from A is ILLUVIATED
C horizon = unconsolidated regolith
R horizon = bedrock
Texture
Clay <0.02mm
silt <0.2mm
Sands <2mm
Used to classify soils
Can affect porosity and permeability
Structure
bulk density (mass/vol)
Platey, blocky, prismatic
Chemical structure
pH?
mineral structure
How does Geography affect soil formation
Climate
T affects chemistry and organic matter
P affects E and I height
relief/topography
Parent material
impacts vegetation growth on soil
Organic activity and matter
Affect decomposition and recycling of O layer via earthworms, bacteria
Time
Affects horizon development
GEOGRAPHY OF SOILS
Pedogenesis and pedogenic regimes
Distinct soil processes lead to soil orders
Tropical = iron rich, highly weathered from strong leaching and clay-rich B layer
Most nutrients stored in vegetation, not soil
Why care?
SUSTAINABLE SOIL MANAGEMENT FOR AGRICULTURE
Mismanagement causes land degradation
Lucrative business
Carbon sinks
Absorb a lot of CO2, possible mitigation to global warming
bad farming and land clearance
affects yields
VEGETATION
Combination of plant and floral species and the land they cover
Primary producers
base of the ecosystem
Adapt according to bgeog of the area
Plant succession
Evolution of pioneer communities to climax communities
Increased complexity
Stable system at climax = MICROCLIMATES FORM
ECOTONES
Where 2 distinct ecosystems meet
can be gradual or sharp
occurs along elevation changes
BIOMES
large scale communities of plants and animals
Determined by principle of limiting factors
factor least in supply determines growth
5 Major types
Forest
Savanna
grassland
Desert
Tundra
Different ways of adaptation
ANTHROPOCENE and human impacts
New geological era, epoch of humans
Impacts
Env pollution
Habitat removal and damage
Changing structure of soils and ecosystems
Altering species composition
Overexploiting resources
introducing exotic organisms
elimination of biological pests
Improper waste disposal
Large ecological footprints
DISTURBING EQUILIBRIUM
Annoying other biotic species
enroachment, fragmentation and destruction
implications at all scales
feedback from micro to macro scales
Primarily tropical rainforests
Affect processes in spheres
Biodiversity loss
-ve impacts on atmosphere
humans destroy habitats --> impacts env --> impacts humans
EXTINCTION
Permanent loss of species from an area
Reduces biodiversity and drives evolution
Caused via human habitat destruction, over-harvesting, species INTRODUCTION
SINGAPORE'S BIOMES
Coastal and lowland dipterocarp
Trees <50m
Evergreen w/ buttress roots
10k plus fauna species
Nutrient-poor soils
Primary (old growth) + Secondary (succession from abandoned/disturbed land
Left with 0.2% primary at BoGa and Bukit Timah nat res
signs of enroachment and fragmentation
role as green lungs
Land loss due to increased urbanisation
need for habitat preservation
Park spaces, recreation and education
ultimately how sustainable is it?
MANGROVES
Salt-tolerant vegetation
Salt exclusion via leaves and roots
BRA --> breathing and anchorage via pneumatopores
PROVIDE HABITAT FOR ESTUARINE SPECIES
TIDAL PROTECTION DUE TO REDUCTION OF WAVE ENERGY
Carbon sink
Government conservation
Mangrove engineering
combining human knowledge with natural ecosystems