Blue and Green Algae in Missouri

            Cyanobacteria, commonly known as Blue-green algae, are microscopic organisms that are naturally present in lake and steams.  Under the normal conditions, they will be present in low numbers.  But blue-green algae can become very abundant in warm, shallow, undisturbed surface water that receives a lot of sunlight.  When this kind of situation occurs in water, blue-green algae can form blooms that looks like scums or floating rafts that occupies the surface of the water.  Some of the blue-green algae are harmless but some could produce toxins that could pose a serious health risk to people and animals when they are exposed to them in large enough quantities.  People’s health could be in danger when water containing high levels of blue-green algal toxins is swallowed, through contact with the skin or even when airborne droplets containing toxins are inhaled while swimming, bathing or showering.  Over exposure to these toxins could cause irritation of the skin, eyes, nose and throat and inflammation in the respiratory tract.  Although recreational contact to such toxins, such as swimming and household contact is not expected to cause health effects, individuals who are especially sensitive could experience mild symptoms such as skin, eye or throat irritation or allergic reactions.   Even though the potential health effect of long –term exposure to low levels of blue-green algal toxins has not been studied, knowing and understanding the serious health and environmental effect of the blue-green algae could be very useful when time presents itself. 

            In order to control the over growth of blue-green algae in Missouri waters, one must first obtained the scientific knowledge of such organism.  As mentioned before, blue-green algae are very primitive cyanobacteria.  Even though they carry the name of algae, they are truly bacteria.  The word cyano means blue, hence the fact that these organisms often appear blue-green in color.  So why do we still call them blue-green algae?  Because cyanobacteria photosynthesizes like algae, which explains why they are very abundant in warm, shallow, undisturbed surface water that receives a lot of sunlight. 

            There are mainly two groups of blue-green algae:  the planktonics and the mat-formers.  The first type, planktonics blue-greens are microscopic organisms we often see in typical pea-soup green color waters.  Of this type of blue-green algae, the most common types of planktonics are Anabaena, Aphanizomenon, and Microcystis. (Purdue, Lembi) The abundance of such bacteria causes the water to appear green and turbid.  And when these blue-green algae rise to the surface of somewhat static waters, they could bind with each other to form a yellowish-green scum.  This kind of formation is very typical of most planktonic blue-green algae.  The planktonics form surface scums in order to deflect and block sunlight to other types of algae and aquatic plants that live in deeper part of the water column.  By doing so, blue-green algae can cut off the proton supplies that the sunlight provided in order to starve the other competitors in the water to death.  Because of the fact that cyanobacteria feed on nitrogen and phosphorus, runoff of fertilizers, organic waste compounds and other sources of Nitrogen and Phosphorus into surface waters could stimulate the growth of blue-green algae, causing heavy infestations or blooms.  These mats are not only toxic but odorous as well. 

            The toxicity among these cyanobacteria in general is well researched and characterized.   There are reports of cyanobacteria in water consumed by livestock causing deaths, bacterial infections among them.

References:

http://www.archwaterworks.com/Docs/ManagmentofBlueGreenAlgae.pdf

http://www.btny.purdue.edu/pubs/APM/blue-green_factsheet.pdf