Using temperature & light data loggers to manage a healthy lake and combat algae blooms

A

lgae blooms in inland and marine waters are becoming more and more frequent as climate change disrupts the different ecosystems around the world. This leads to an increasing effort to predict and manage cyanobacteria blooms and minimize its potentially fatal impacts on living organisms.


Exposure to these blooms can lead to serious health issues such as, skin irritation, gastrointestinal illness, even liver damage and certain cancers. They can sometimes also deplete dissolved oxygen which causes fish mortality.


These blooms are usually detected by analysing the way phycocyanin (a pigment native to the cyanobacterium) absorbs and reflects light. You must also consider the water temperature, as this parameter can give you a head start on when these blooms will arise.

Using temperature & light data loggers to manage a healthy lake and combat algae blooms

Measuring PAR

Solar radiation falling between 400 and 700 nm is called “photosynthetically active radiation” or PAR for short. This parameter is very helpful in freshwater lake environments, as it is the determining factor of aquatic productivity. This is true for plants who rely on PAR for there growth cycle, but a number of other organisms do as well.

Measuring water turbidity

Turbidity is a measurement of water clarity. Turbidity can be influenced by several factors present in waterbodies, including the presence of mud, silt, algae, or chemicals in the water. The significance of turbidity in a lake depends on the season and the ecosystem within. turbid waters prevent the passage of light necessary for plant growth. Algae-related turbidity is often associated with eutrophication and hypoxia (the over enrichment of waters by nutrients and oxygen depletion). Very high turbidity can actually cause fish and other organisms to suffocate.

Measuring thermal stratification

Stratification is the relationship between water density and temperature. In the summer, solar radiation heats the top layer of the lake, thus becoming less dense. The lower level (hypolimnion) gets less light and remains colder and denser. Because of this phenomenon, both parts do not mix, forming an interstice layer called the thermocline. Algae and zooplankton in this layer during the hot summer months, but when they die, they are decomposed in the sediments., using up large amounts of dissolved oxygen in the process. Because the body of water does not mix in the summer, the top layer (hypolimnion) can become anoxic.

Conclusion

The use of small temperature and light data loggers is an inexpensive and compact way to monitor the health of your lake and predict the rise of algae blooms before they become a problem. You must make sure that the logger used is well calibrated and that it has the full spectral breakdown (RBG and IFR) and a PAR conversion.