Unit 2 AoS 2 - water quality Flashcards
What is turbidity?
Measure of suspended fine particles in water
What is biological oxygen demand?
amount of organic material (e.g waste) in the water
What is salinity?
Salt levels (measured in mg/L)
Describe the term ‘nutrient levels’
Chemicals that are essential to metabolism and growth in organisms
What does ‘light intensity’ mean?
Measure of the amount of sunlight reaching a surface
What is pH?
The measure of acidity or alkalinity (basic) of water or soil
Describe the term ‘dissolved oxygen’
a measure of how much oxygen is dissolved in the water - the amount of oxygen available to living aquatic organisms.
Describe the term ‘temperature’ regarding water quality
Temperature of the water
What is an environmental indicator?
Factors of the environment identified and used as a way of assessing the overall condition of an environment.
What does ‘ecological niche’ mean?
The description of an organisms structural and functional role in an ecosystem
What does ‘range of tolerance’ mean?
tolerance to chemical and physical conditions within which an organism will live, grow, and function normally
What is a generalist?
A species that occupies a broad ecological niche and feeds on many kind of food
What is a specialist?
Organisms which have very specialised niches and feed on very few types of food
What does ‘tolerance limit’ mean?
The point where physical and chemical conditions become harmful to an organism
What does threshold mean?
The point at which a level or concentration is reached at which an effect is observed
What does the term ‘limiting factors’ mean?
Any condition that approaches or exceeds an organisms limits of tolerance.
Why are environmental indicators useful?
- Helps assess human impacts
- Can be used as early warning signs
- Can be used in rehabilitation or restoration projects
How is data from indicators collected?
- Field observation
- Field sampling
- Remote sensing
- Existing data
What are the different types of indicators?
- Physical
- Chemical
- Biological
- Socio-economic
Physical indicator
(Physical feature)
Chemical indicator
(Chemical factor)
Biological indicator
Effects on a plant or animal)
Socio-economic indicator
(effects on people)
What are indicators used for?
Management
Monitoring
reporting
How is turbidity measured?
Can be measured using a Secchi disk
How is light intensity measured?
Measured with a datalogger probe, light probe, Secchi disk
How is pH measured?
Can be measured using pH strips, liquid indicator, or pH meter
How is the level of dissolved oxygen measured?
Measured using a certain device
How is biological oxygen demand measured?
uses a device specific for this use
How is salinity measured?
Measured by conductivity - measures the number of inorganic salt materials dissolved in a soil or water sample (Conductivity probe)
What are impacts of turbidity in the environment
- Influences penetration of sunlight, reducing light ∴ reducing photosynthesis
- Make it difficult for organisms relying on sight for food
- Higher than normal levels could indicate soil erosion
What are impacts of different light intensities in the environment
A decrease in light intensity may reduce the rate of photosynthesis reducing growth & potentially affecting animals that rely on plants for food/habitat
How does pH impact the environment
Can impact the number and type of organisms present in soil or water
How does the level of dissolved oxygen impact the environment?
Oxygen is essential for life in the water (plants and animals)
- DO levels b/w 1-5 some living things
- DO levels below 1 – no life in the water
How does biological oxygen demand impact the environment?
- Waste is broken down by bacteria, which need oxygen for that process.
- Release of waste into water will increase the activity of bacteria that break down organic material, and increase BOD of the water
- BOD is a measure of cleanliness
- BOD below 1ppm – extremely clean water
- BOD 2 or more – indicated organic pollution of the water
How do different levels of salinity impact the environment?
Many species only survive within certain salinity ranges
How do different nutrient levels impact the environment?
Excess amounts of nitrogen or phosphorus in an environment can increase algae and water plants choking waterways and causing decreases in Oxygen levels
How does temperature impact the environment?
- Increase in temp reduces conc. of DO, increases the rate of photosynthesis and increases the demand for oxygen (BOD)
- All species have different temperature tolerances
What are some examples of biological indicators
- Frogs
- Fish
- Algae
- Aquatic macroinvertebrates
- Introduced species
- Soil biota
- Bacteria
What are some examples of both physical and chemical indicators?
- Turbidity
- Biological oxygen demand
- Salinity
- Nutrient levels
- Light intensity
- pH
- Dissolved oxygen
- Temperature
What threats to humans pose to fish?
- Over fishing
- competition from introduced fish and diseases
- Siltation
- Clearing of riverbank and floodplain vegetation
What are some benefits of using fish as an environmental indicator?
they are easy to identify and live for long periods
What are some disadvantages of using fish as an environmental indicator?
- Fish can swim away from poor environmental conditions
- Water tolerances for many Australian Fish are not yet known
How can algae be used as an environmental indicator?
Indicates nutrient levels in water
What are some benefits of nematodes as environmental indicators?
- Have a permeable skin
- Easy to capture
- Are small and widespread
- Have stable populations
- Important position in detritus food web
- Inexpensive to sample
How can bacteria be used as environmental indicators? (E. Coli)
- Presence is a measure of faecal contamination
- Presence may indicate the presence of other pathogens
What is a biomarker species?
Species which have a low threshold for a particular contaminant
What is a bioassay?
Exposing an indicator organism to a test material & measure the response
What is siltation?
pollution of water by fine particulate
Why is the lifespan of a fish beneficial as an environmental indicator
allows us to evaluate extinction risk and whether a pest fish species could become invasive
How do different types of algae indicate water nutrients?
Desmids live in low nutrient water
Diatoms replace desmids in as water nutrients increases
At higher nutrient levels Green algae & blue-green algae become the most abundant
What is the process of eutrophication?
- Increase algae
- Increase in organisms that feed on algae
- Increase in BOD
- Overnight oxygen levels fall
- Organisms die
- Decomposers break down remains
- Increased nutrients
- Stimulates algal bloom
Why are aquatic macro-invertebrates beneficial environmental indicators?
- Always in the water & using it
- Constantly affected by its quality
- Small and relatively easy to find
- Live in water for long periods of their life
- Exhibit predictable & detectible responses to changes in water conditions
- They form the bottom of the aquatic food chain, what affects them changes the whole system.
What is SIGNAL
index of water pollution developed for eastern Australia.
What is SIGNAL short for?
stream invertebrate grade number – average level
How is SIGNAL score calculated?
calculated by combining the grades for pollution sensitivity for all the aquatic macroinvertebrate taxa present at the site with the numbers of each taxon that are present.
How can introduced species be used as environmental indicators?
- Can affect food chains & habitat structure
- Absence of introduced species indicates good health of ecosystem
- Large numbers indicates ecosystem is under stress
What is a disadvantage of using introduced species as an environmental indicator?
Difficult to monitor distribution & abundance of all introduced species
What are some examples of introduced species?
Cane Toad
Rabbit
Fox
Feral pig
Feral goat
Carp
European wasp
Northern Pacific Sea star
Gorse
Phytophthora [soil borne water mould]
Blackberry
Serrated tussock
Why is soil biota beneficial as an environmental indicator?
Sensitive to changes in soil conditions
