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.

Friday, August 16, 2019

Biodiversity Walk at Kaikondrahalli Lake

As part of the Citizen Science and Lakes Initiative another Biodiversity Walk was held at Kaikondrahalli lake on Sunday, August 11th 2019. The walk was led by Aswathy Joseph and started near the Kalyani entrance. Aswathy started by explaining the importance of mutualism in nature. In the case of ficus trees, each variety of ficus trees has a certain species of wasp essential for its pollination. The wasps in turn depend on the figs for a safe haven to lay their eggs. Image 2 below is of a ficus tree being worshipped near the Northwestern Entrance.

Image 1: Aswathy leading the Biodiversity Walk at Kaikondrahalli lake
Image 2: A ficus tree being worshipped at the lake
Aswathy mentioned that a week ago the tree was blooming with red figs but a week later we could only spot a couple on the entire tree. An interesting story she shared was that since so many birds, insects and mammals depend on ficus trees throughout the year, one of the ficus trees in the area always has figs growing on it. She also stated that figs were one of the first plants domesticated for human consumption. Another species we came across was the Babul tree as shown in Image 3, it’s a thorny tree with yellow flowers. The same Babul species in Jakkur lake was more like a shrub while the one we saw in Kaikondrahalli lake was a surprisingly large tree. 

Image 3: Participants observing the large Babul tree
Throughout the walk all the participants were really engaged and shared any additional knowledge they had on the biodiversity of plants and insects around the lake. What was supposed to be a one and a half hour walk lasted for over two and a half hours due to the enthusiasm of the participants. 

Venkatesh Peedhanna - one of the younger well diggers was also a participant

To learn more about the previous walks we have had, please refer to the following links:

Monday, June 24, 2019

Varthur Lake Wetland Workshop

Sensing Local along with Biome Environmental Trust, Whitefield Rising and Varthur Rising organised a public participatory planning workshop to develop a Wetland for Varthur Lake as part of its rejuvenation project on 5th January, 2019.  Various stakeholders were brought together to discuss and arrive at an appropriate guidelines for designing the Varthur Lake Wetland


A link to a report of the event -  in the Hindu

Friday, June 21, 2019

In-Stream Decontamination System at Saul Kere

In-Stream Decontamination system is a small-scale collaborative project constructed near the southern inlet of Sowl Kere.  This intervention is part of an ongoing collaboration which includes diverse partners spanning Design, Engineering, Civil Society, and Science perspectives. The six-fold partnership includes input from Biome Environmental Trust (project management, collaboration, coordination), MAPSAS (community engagement), Eco Paradigm (engineering & construction), Commonstudio (design), ATREE (monitoring), and Wipro (fiscal sponsorship).  

This small scale intervention “model Nallah”, approximately 2M Wide and 8M long has been constructed next to the STP at Saul Kere.
Within this space, we will run a series of experiments with jelly stones and terracotta rubble metarials. The first treatment will test the removal of organic contaminants by means of jelly and Terracotta rubble material. Terracotta has properties which makes it a viable biofilter media for urban wastewater. We plan to test the system for flows between 2.4 and 9.6 KLD.


The ultimate aim is to use the insights of the Sowl Kere studies to develop a series of larger interventions which can be placed directly within nallahs to prevent the contamination and eutrophication of urban lakes. We call this larger approach “Strategic In-stream Systems” or “STRAINS”— decentralized, frugal, flexible, and inclusive.

Sunday, June 16, 2019

Biodiversity Walk at Rachenahalli Lake

After an excellent walk at Jakkur our next walk was at Rachenahalli on the 9th June 2019 as part of the Citizen Science and Lakes initiative.  About 25 people joined us for the walk of which 15 were children. Aswathy led the walk and started with the tree we were standing under, The Jamican Cherry tree also called Singapore cherry or Kaskase tree.  She spoke about how the small birds love the berries of this tree and that the red berries are very sweet and can be consumed by humans too.
Under the Singapore Cherry tree

Further we came across Black Babul tree or the Karijali tree

Black Babul or the Karijali tree

and  the Sacred fig tree.  

                                                        Sacred fig or The People Tree

Fig fruit

For more information on the ficus and the Black Babul tree please refer to our Biodiversity walk at Jakkur lake   

As we moved towards the Wetlands area children got to observe the behaviour of Purple moorhen which was hopping on the wetland reeds.  Purple moorhens nest and roost in the wetlands.

                                       Children observing purple moorhen in the wetland

                                                                Purple moorhen

As we were observing the moorhens a plant in front of us had these strange leaves.  These are leaf gall an abnormal growth of the leaves caused by insects. Different insect creates different shaped galls. These are not harmful to the plants/trees

                                                                  Galls on the leaves

Children were fascinated to observe Indian Shag or Indian Cormorant. It diving into the water to catch fish and then surfacing out, sitting on a nearby stump and drying its wings.

Indian Cormorant drying its wings

The walk ended at the gazebo with children seeing some pictures of butterflies. They tried to identify the butterflies that they have seen.

Wednesday, June 12, 2019

Testing for Lake Water Quality: What are the parameters that we should check for

If you are trying to rejuvenate a lake and want to know more about what parameters to test for, you can use this blog as a reference. Lakes in Bangalore are often polluted with sewage inflows, industrial effluents and catchment runoffs. To better understand the water quality of the lake is, we have created 4 categories
(A) The basic parameters
(B) Industrial effluents
(C) Pesticides
(D) Testing for the first time

(A) The basic parameters that need to be tested for in a lake area:
  1. pH
  2. BOD
  3. DO
  4. TDS
  5. TSS
  6. Nitrates
  7. Phosphates
  8. Total Coliform Bacteria
  9. Free Ammonia
(B) If industrial effluents are being discharged into the lake, the additional parameters that need to be tested for are listed below. The general standards for discharge of effluents, can be accessed through the following link: http://cpcb.nic.in/industry-effluent-standards/
  1. Arsenic
  2. Cadmium
  3. Mercury
  4. Zinc
  5. Chromium
  6. Lead
  7. Nickel
  8. Iron
  9. Copper
(C) If there is possible contamination from pesticides, the additional parameters that need to be tested for are:
  1. Alpha BHC
  2. Beta BHC
  3. Gamma BHC
  4. OP-DDT
  5. PP-DDT
  6. Alpha Endosulphan
  7. Beta Endosulphan
  8. Aldrin
  9. Dieldrin
  10. 2,4-D
  11. Carbonyl
  12. Malathion
  13. Methyl Parathion
  14. Anilophos
  15. Chloropyriphos
(D) If you are testing the water quality for the first time 
We recommend doing a complete potability test according to the drinking water standards set by the Bureau of Indian Standards (BIS 10500) It can be accessed through the following link: http://cgwb.gov.in/Documents/WQ-standards.pdf

Testing Labs in Bangalore

The cost for water quality testing could vary anywhere from Rs 1,500 to Rs 15,000 depending on the parameters being tested. For more accurate information contact a water quality testing lab and mention you want to test lake water quality, they will send you the list of parameters that they can test in their lab and the respective quotation. Listed below are some of the testing labs in Bangalore along with its links and contact information.

Lab Name
Contact Information
New BEL road
98441 68829
74114 39839
JP Nagar
080 2658 9777
96869 77009
080 2350 2684
Kempegowda Layout
91523 22165
95388 88098
080- 23356415
080- 2839 2230

Surface Water Quality Standards

Testing the above mentioned parameters will tell you what the quality of the lake water is but to know what standard it needs to meet depends on the end use of the water. The Central Pollution Control Board (CPCB) of India defines water quality from the users point of view as ‘the physical, biological and chemical characteristics of water by which the user evaluates the acceptability of water’. Based on the primary water quality criteria CPCB has classified surface water into 5 classes (based on the expected end use), as shown below in Image 1.

Image 1: Classes of Surface Water

To use the lake water as a source of drinking water it needs to meet Class A or C standards, similarly to use the lake water for propagation of wildlife and fisheries it needs to meet Class D standards. As per data collected by the Karnataka State Pollution Control Board, most lakes in Bangalore are classified as D or E. To know more about the different standards as per IS-2296 refer to Table 9.1 in the following link https://elibrarywcl.files.wordpress.com/2015/02/surface-water-quality-standards-as-per-is-2296.pdf


Lakes Water Samples Classification by the Karnataka State Pollution Control Board

Water quality parameters and the importance of each