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LU8: Landuse & Its Impact on Inland Water (Physical (Wetland…
LU8: Landuse & Its Impact on Inland Water
Physical
Wetland destruction
Forestry/ Clear cutting
Agriculture
Urban development
Highway construction
Diversion of stormwater & wastewater
Global warming :fire:
Due to
Greenhouse gases (CO2 & CH4) :
Effects :!:
c) streams become too warm
d) Long dry periods for small streams
e) Longer ice-free periods for lakes, warmer water, deeper thermocline
b) reduction in water flows
a) high evapotranspiration
Dam & Impoundment building
Effects :!:
b) Changes in downstream sediment balance > delta become smaller
c) Hydraulic modification > loss of habitat & wetland areas
d) Increase of mercury level in fish
e) Release greenhouse gases due to decomposition (flooding)
a) Cold downstream water & low DO affect the native aquatic organisms
Purpose
Hydroelectric power, control flood, water storage
Chemical
Sources of pollution
Point
Municipal & industrial discharge (e.g. dioxins & PCBs)
Non-point
Agricultural & urban runoff (e.g. DDT, toxaphene, pesticides)
3 major impacts
Cultural eutrophication
Accumulation of toxic pollutants
Loss of DO
Acid rain, air pollution, stream acidity
AIR POLLUTION
Natural rain: pH 5.6; acid rain: pH 5 - 5.5, gases from burning fuel (S & N)
Acidity in natural rain: H2 CO3, SO4 2- (volcano), sulfide ore smelter & NO2 (lighting)
Power stations (SO) > dissolved in rainwater (H2 SO4) > falls on lake & streams (acidified) > :fish: :skull:
STREAM ACIDITY
Acid rain + low buffering capacity in soil= acid lakes (pH 4.5 - 6)
Normal lake (pH 6.5 - 9) higher than natural rain, buffering of H+ by soils/ limestone (CaCO3)
Free H+ can replace other cations in soil, release free ions of Cu, Zn, Al, heavy metal > high conc. are toxic aquatic organisms & algae
ACID RAIN
metal+lake acidity= toxic to :fish: (precipitate/ produce mucus on gills) > interfere Ca & Na transfer, prevent O2 transfer
xtra Al precipitate with soluble PO4 3- > phyto & zooplankton decline > oligotrophic lake
pH< 5&6 caused reduction in animal & plts diversity
Biological
Direct changes by human
Introducing exotic sp. (intentionally)
Accidentally introduced sp.
RAMSAR Convention :tanabata_tree:
RAMSAR site
Protected area
site containing rare/unique wetland types
site o f international importance; conserving biological biodiversity
6 sites
Tasik Bera, Pahang
Tanjung Piai State Park, Johor
Pulau Kukup State Park, Johor
Sungai Pulai Wetland, Johor
Kuching Wetland National Park, Sarawak
Lower Kinabatangan-Segama Wetland, Sabah
Convention of Wetlands of International Importance
Maintenance of ecological character, achieved via implementation of ecosystem approaches
Focus on conservation & sustanable
WETLANDS
Values :
Aquaculture
Timber/ Fibre Production
Fuel
Aesthetics, Education, Recreation
Food
Functions
Physical/ Hydrological
Coastal protection
Ground water recharge
Sediment traps
Atmospheric equilibrium
Flood control
Chemical
Waste treatment/ Pollution interception
Biogeochemical cycling
Biological
Habitat
Migration
Nursery