Tuesday, September 24, 2019

Algae and Algal Blooms

What are Algae?

Algae (one alga, but several algae) are type of plant-like living thing that can make food from sunlight by photosynthesis. Algae are unicellular or multicellular organisms.  They are mostly found in rivers, lakes and sometimes in seas too. Algae are very important because much of the Earth’s oxygen is generated by algae.

Algae can be classified into 7 major types

- Euglenophyta (Euglenoids)
- Chrysophyta (Golden-brown algae and Diatoms)
- Pyrrophyta (Fire algae)
- Chlorophyta (Green algae)
- Rhodophyta (Red algae)
- Paeophyta (Brown algae)
- Xanthophyta (Yellow-green algae)
Blue-green algae is not an algae but a kind of bacteria and hence does not come under the different types of algae listed above.
What is the difference between Algae and Blue-green algae/Cyanobacteria ? 

The main difference between algae and cyanobacteria is that algae contain chloroplasts (eukaryotes) whereas cyanobacteria do not contain chloroplasts in their cells ( prokaryotes). However, both algae and  cyanobacteria derive their energy through photosynthesis.

Cyanobacteria are also commonly referred to as Blue-green algae , even though they are actually bacteria(prokaryotic),.

There are over 2000 species of blue-green algae.  

Is blue-green algae (same as cyanobacteria) Useful or Harmful ?  
Some types of blue-green algae are used for treating precancerous growths inside the mouth, boosting the immune system, improving memory, increasing energy and metabolism, lowering cholesterol, preventing heart disease, healing wounds, and improving digestion and bowel health.

Wild or cultivated algae Spirulina, Chlorella and Klamath are all blue-green algae (or cyanobacteria), known for their health benefits. Klamath can only be found in one place on earth, Lake Klamath in Oregon, United States. Spirulina is also cultivated in open-channel, ponds.

Some species of blue-green algae produce harmful toxins which take effect when eaten, inhaled or skin contact is made. Ingesting toxins can also cause gastroenteritis symptoms, such as vomiting, diarrhoea, fever and headaches. Toxins can also have an effect on the liver and the nervous system.

A series of tests has to be done to identify the type of blue green algae and to establish if they are useful or harmful. Visually this difference cannot be identified

What are algal blooms?

An algal bloom is a rapid increase or accumulation in the population of algae. This results in a dense layers of tiny green plants that occur on the surface of the water.  These blooms occur when a lake/water body has a high concentration of nutrients (especially phosphorus). High levels of nutrients are often caused by human pollution, such wastewater, sewage, manure and fertilizer runoff from agriculture.

PC: Google
The harmful effects from such blooms is due to the toxins they produce as well as due to the reduced level of oxygen in the water as these algae use up the oxygen in the water. This can then lead to fish kills. Bird kills are caused when birds eat contaminated fish.

Not all algal blooms are harmful. In some cases algal blooms only discolor water, or produce a smelly odor, or add a bad taste to the water. 

What are the precautions that I need to take when I see a water body with algal blooms ? 

- Do not swim or boat in areas where the water is discolored  or where you see algae on the water.
- If you get in contact with the algae rinse off with fresh water as soon as possible.
- Do not let pets or livestock swim in or drink if the water is discolored  or where you see algae on the water.
- Do not use the water for irrigation or watering lawn with algal growth
- Report any smell or taste in wells/borewells.

 How can we prevent algal blooms?

Algae need light, nutrients and high temperatures for optimal growth. Lowering any of the three will help reduce algal growth.  Stagnant waters see rapid growth of algae. Algal blooms are less frequent in flowing/moving water. Preventing fertilizers and pesticides runoff, waste water, sewage entering into the water body can prevent algal blooms.

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