Water & Enviro Week 5

Producers

Utilise solar/chemical energy to synthesis their own organic requirements from organic matter

Consumers

Incapable of synthesizing their own food - feed on organic compounds

Decomposers

Breakdown organic matter for their requirements or release inorganic compounds to be utilised by producers

Ecological equilibrium

Balance between living organism productivity & death/decomposition

High biodiversity

Unpolluted ecosystems inhabited by wide variety of organisms

Assimilative capacity

Extent to which a waterbody can receive pollution without significant deterioration

Assimilative capacity varies on

Self purification capacity

Dilution

Polluted river joined by less polluted tributaries/during rains, water volume increase reduces pollutant concentration

Sedimentation

River reaches flat lands - spreads, reducing velocity and suspended matters settle out

Aeration

Turbulence mixes air into water increasing dissolved oxygen - facilitates chemical/microbiological processes

Adsorption

Pollutants adsorb onto surfaces reducing aquatic concentration

Phyto-remediation

Aquatic plants/vegetation absorb nutrients and remove pesticides/heavy metals

Floatation

Turbulent water bubbles lift pollutants to surface forming froth

Microbial degradation

Microbes utilise pollutants as energy source

Bacterial decay

Enteric & pathogenic organisms die due to inhospitable environment

Ecological sampling

Field tests - response of aquatic organisms to pollution & effect on habitat

Physiological & biochemical sampling

Lab tests showing response of organisms to variations of water quality

Bioassays & toxicity test

Rapid determination of acute toxicity of water using test organisms

Chemical analysis of biota

Organisms to be able to bioaccumulate contaminants or exposed to polluted water - level of contamination measured

Historical & morphological

Examination of organisms for morphological indications of environmental stress

Microbiological sampling

Typically microbiological examination of water for presence of microorganisms indicative of faecal pollution

Most biological monitoring of waters is

Ecologically based using benthic macroinvertebrates

Why are benthic macroinvertebrates used to assess river quality

1. Found in all fresh water

2. Stay in one location

3. Respond to physical damage to their habitat & pollutants in water

Kick sample

Standard hand-net procedure used for sampling benthic macroinvertebrates

Surber sampler

Standard hand net with a 300mm square frame

Artificial substrate sampling

Substrate material in a mesh bag placed on riverbed

Mayflies, stoneflies and caddis flies are indicative of

Good water quality - intolerant of pollution

Dragonflies, craneflies and alderflies are indicative of

Fair water quality

Leeches, worms and snails are indicative of

Poor water quality

Infectious disease needs what to spread

1. Source

2. Route of transmission

3. Exposure of a susceptible living organism

Control of infectious disease is based on

Curing and breaking route of transmission

Water associated infectious diseases are classified into

1. Water borne

2. Water washed

3. Water based

4. Water related