Why we monitor air temperature: Air temperature influences the temperature of the water.
What influences air temperature: Air temperature is influenced by the energy from the sun, weather patterns, and the
1. Turn on the thermometer and make sure it is set in Celcius (°C).
2. Measure the air temperature first by holding the thermometer in a shady location
and let the thermometer adjust to the ambient conditions for at least 1 minute before
Why we monitor water temperature: Water temperature influences the rates of chemical and biological processes and affects
other measured parameters (e.g. as temperature increases, the maximum amount of dissolved
oxygen decreases). Water temperature is one of the most important parameters for aquatic
organisms. Many animals have adapted to a specific range of temperatures and temperatures
warmer than these can cause stress or even death. For example, trout are cold water
fish that have trouble surviving when the water temperature is above 20 °C.
What influences water temperature: Water temperature is determined by the climate of the watershed, seasonal patterns
and local influences. During the summer, lakes and reservoirs generally have a layer
of warm and less dense water that floats above colder, denser water at the bottom
of the reservoir. The density difference between these two layers creates a surprising
amount of resistance to mixing, so the two layers stay separate for much of the summer.
In the fall, the temperatures cool at the surface and the lake eventually mixes from
top to bottom. A winter lake, especially one with ice cover, may have “reverse stratification”
where slightly warmer water floats above the most dense water, which occurs at about
4.5 °C. In the spring, the lake mixes from top to bottom. The warming of the late spring
and summer sun creates the warm later again.
Local influences on lake temperatures include upstream discharges of warmer water
from natural springs or cooling water from power plants, shading provided by the littoral
zone (the vegetation along the edge of the lake), lake depth, and the amount of suspended
material in the water. recording the temperature.
1. Measure the water temperature by submerging the thermometer two-thirds below the
surface of the water.
2. Take the measurement in a central flowing location.
3. Let the thermometer adjust to the water temperature for at least 1 minute before
removing the thermometer from the water and quickly.