HABs and Climate
Increased water temperatures from climate change can cause higher occurrence of harmful algal blooms (HABs), increasing intensity, frequency and distribution. Warming waters coupled with increased nutrient addition can favor cyanobacteria.
Not all HABs are formed of cyanobacteria; a HAB is any excessive amount of algae that causes negative impacts on other organisms, water quality, recreation or the economy. There are many forms of algae that can form nuisance conditions and create a HAB. Some forms of Chlorophyta (green algae) produce taste and odor causing issues in drinking water and can form extensive thick mats of algae within littoral zones of lakes and within streams smothering substrate and fish breeding habitat. The foremost concern with HABs is toxic conditions, Cyanobacteria are the main perpetrator, however some forms of diatoms and dinoflagellates can create toxic conditions that are harmful to other organisms and humans.
Bodies of water with increased acidification are more susceptible to HABs. The carbonic balance, which is linked to the increased Co2 concentrations, can also increase the growth rate of all forms of algae while reducing the overall nutritional value, thereby causing a trophic imbalance. Recent studies have shown that bodies of water with reduced calcium levels can also lead to trophic impaction. Large bodied zooplankton need adequate calcium levels to reproduce, without it smaller bodied zooplankton can dominate causing a trophic cascade effect. The trophic cascade can be amplified by invasive and introduced species.
Invasive mussels such as Zebra Mussels and Quagga Mussels will feed on Chlorophyta and other forms of algae while leaving the Cyanobacteria behind. This will allow for increased Cyanobacteria blooms with the potential of toxic conditions.
Increased temperatures coupled with increased runoff and biologically available nutrients will mean an increase in HABs this August/September. All suspected HABs should be analyzed for potential toxic conditions.
