1. Topic 2.2
Measuring Abiotic Factors

2. Abiotic Factors
– Temperature
– Rainfall
– Light
Climatic Factors
– pH
– Salinity
– Nutrients
– Availability of water
Edaphic Factors
(soil)

3. Measuring Abiotic Components
• There are 3 main types of ecosystem where
you might need to measure abiotic
components:
1. Marine (sea, estuary, salt marsh, mangrove
2. Freshwater (river, lake, wetland)
3. Terrestrial
Bozeman Science – what are abiotic factors

4. 1. Marine Ecosystems

5. 2. Freshwater Ecosystems

6. 3. Terrestrial Ecosystems

7. Distribution of Earth’s Water

8. Examples of Abiotic Components
• Marine
Ecosystem
–
–
–
–
Salinity
pH
Temperature
Dissolved
oxygen
– Wave action
• Freshwater
Ecosystem
–
–
–
–
–
Turbidity
pH
Flow
Temperature
Dissolved
oxygen
• Terrestrial
Ecosystem
–
–
–
–
–
–
Temperature
Light intensity
Wind speed
Soil particle size
Slope
Soil moisture
content
– Drainage
– Soil mineral
content

9. Measuring Abiotic Factors
• Light
– Use a light meter
– Use a standard and fixed height
– Avoid shade
– Take readings at the same time of day
– Standardise the direction it points

10. Measuring Abiotic Factors
• Temperature
– Use an electronic probe with a datalogger
– Use a standard height above ground or a standard
depth

11. Measuring Abiotic Factors
• pH
– Use an electronic probe with a datalogger
– Use a standard depth
– Make sure the probe is clean
– Make sure it is calibrated properly

12. Measuring Abiotic Factors
• Soil Particle Size
– Large (stone-sized) particles can be measured
individually
– The volume of smaller particles can be measured
using a series of successively finer sieves
– Even smaller particles can be separated by
sedimentation

13. Measuring Abiotic Factors
• Windspeed
– Use a digital anemometer if possible
– A homemade propeller could be made
– Indirect measurements can be made using the
Beaufort scale

14. Measuring Abiotic Factors
• Slope
– Use a clinometer
For a slope of x◦:
Percentage slope
= tan(x) x 100

15. Measuring Abiotic Factors
• Soil moisture content
– Weigh soil sample before and after heating and
calculated the mass of water evaporated off
– Repeated readings taken until there is no further
change

16. Measuring Abiotic Factors
• Water flow velocity
– Time how long it takes a floating object to travel a
fixed distance, i.e. Pooh Sticks
– Alternatively a probe with a propeller attachment
may be used

17. Measuring Abiotic Factors
• Mineral Content
– Minerals are non-volatile
– If you have an oven which heats a sample safely to
500 – 1000oC for a number of hours, the
remaining mass will be the mineral content

18. Measuring Abiotic Factors
• Salinity
– Salinity can be measured indirectly by measuring
electrical conductivity (using a conductivity probe
with a datalogger)
– Conductivity is a measurement if the ion content
of a sample of water (in parts per thousand, ppt,
%o)

19. Measuring Abiotic Factors
• Dissolved oxygen content
– Use a dissolved oxygen probe connected to a
datalogger

20. Measuring Abiotic Factors
• Wave action
– Use a dynamometer – an instrument which
measures the force of waves

21. Measuring Abiotic Factors
• Turbidity
– This is a measure of the cloudiness of a water
sample
– It can be measured using a Secchi disc. The depth
to which it must be lowered into the water in
order to just become invisible is measured
– Alternatively a turbidy meter can be used. This
shines light through a sample and records its
absorbance by the sample
List whether each of these methods is suitable for marine, freshwater or terrestrial ecosystems