1.1-c) Measuring Abiotic Factors

• Terrestrial abiotic factors ➞ nonliving factors that relate to a land-based ecosystem

• Temperature: ➞ a measure of heat energy (°C) • It is measured through: ➞ soil temperature (temperature probe) ➞ air temperature (thermometer) ➞ wait until the reading adjusts ➞ take several samples (increases reliability)

• Light intensity: ➞ a measure of brightness of light • It is measured through: ➞ a light meter ➞ hold at soil surface ➞ avoid casting a shadow over the meter

• Edaphic factors: ➞ factors affecting soil (e.g. moisture, pH and nutrients) • It is measured through: ➞ a moisture or pH meter ➞ insert the probe into the soil ➞ wipe probe between samples

• Wind velocity: ➞ is speed and direction of wind (N, E, S, W) • It is measured through: ➞ anemometer (for wind speed) ➞ weather vane (for wind direction)

• Precipitation: ➞ is a measure of rainfall • It is measured through: ➞ a rain gauge ➞ take readings from the scale

• Slope: ➞ is how steep a slope is • It is measured through: ➞ a clinometer ➞ Rise = difference between the highest and lowest point on the slope ➞ Run = horizontal distance ➞ Slope = Run/Rise

• Light intensity: ➞ Different species of plants have varying requirements for light intensity for photosynthesis. ↳ Some plants thrive in direct sunlight, while other plant species prefer more shaded conditions. This can influence the type of plants that can grow in a particular area, affecting the entire food web and ecosystem structure. • Edaphic factors: ➞ The availability of nutrients for plant growth is determined through the composition of the soil. ↳ Many plant species may require more nutrient-rich soils whilst some plant species are able to adapt to nutrient-poor soils in dry and arid ecosystems (i.e. cacti in deserts) • Wind velocity: ➞ Wind velocity has a major impact on seed dispersal, with the speed and direction of the wind determining where and how far the seeds are dispersed - impacting the distribution of plant species.

• Aquatic abiotic factors ➞ nonliving factors that relate to an aqautic ecosystem

• Water temperature: ➞ a measure of the heat of the water (°C) • It is measured through: ➞ a thermometer ➞ allow the reading to adjust

• Water flow rate ➞ is the volume of water that moves in a certain amount of time • It is measured through: ➞ a flow probe/current meter ➞ carry out the float method

• pH: ➞ is how acidic or alkaline the water is • It is measured through: ➞ a pH probe or chemical test ➞ allow the reading to adjust

• Salinity: ➞ is a concentration of salt dissolved in a body of water • It is measured through: ➞ a salinity meter ➞ which gives an Electrical Conductivity (EV) value ➞ high value = high salinity

• Tidal effects: ➞ is how high tide and low tide affect the ecosystem • It is measured through: ➞ a tide guage ➞ to compare the rising and falling tide to a ‘benchmark’ level.

• Water temprature: ➞ The temperature of the water affects photosynthesis rates in plants. ➞ Lower water temperatures indicated typically higher dissolved oxygen. • Water flow rate: ➞ Many organisms can only survive at certain water flow rates, and struggle when rates are too high or too low. ➞ The flow of water is responsible for moving oxygen to some organisms’ gills, and even helps food like plankton flow into the mouths of other aquatic animals. • Tidal effects: ➞ Organisms in coastal areas can be threatened by wave action, light exposure, and drying out.

• Dissolved oxygen content: ➞ a measure of the amount of free oxygen dissolved in water, which can be used to determine the quality of water and assess its ability to support life.

• Biological Oxygen Demand (BOD): ➞ a measure of the amount of dissolved oxygen used by aerobic micro-organisms when decomposing organic matter in water ↳ (BOD is measured in mg l-1 of oxygen consumed over a 5 day period of 20°C)

• Abiotic factors will affect the frequency and distribution of organisms. • The kite diagram shows the distribution of organisms on a rocky shore. Sampling station 0 is at high tide, sampling station 20 is at low tide.