Cyanobacteria, blue-green algae in water and their treatment
What are blue-green algae?
Blue-green algae, also known as smear algae, are actually bacteria and not algae. Scientifically the name is Cyanobacteria and there are about 2000 species, such as Anabaena, Microcystis, Oscillatoria, Spirulina, Stigonema, Tychonema.
In the picture you can see: oscillating movements of the cyanobacteria "Oscillatoria" towards the light, together with the "Gloeocapsa" blue-green algae.
Recording Berkshire Community College Bioscience Image Library
The name "blue-green algae" comes from the pigment phycocyanin, together chlorophyll and carotenoids. This results in a blue-green coloration of the "blue green algae" as it is also called. The Latin name of the blue algae is "cyanobacteria". Cyano comes from the Greek from κυανός kyanós, "blue" and bacterium because it has no cell nucleus and is classified as prokaryotic algae.
The history of blue-green algae
The earth is about 4.5 billion years old and the blue-green algae about 3 billion years. Before that the earth was a dead planet, no living being was present, not even a bacterium.
But about 3 billion years ago the time had finally come. Evolution had invented photosynthesis, and in the still hot ocean the first cyanobacteria set to work. Driven by the energy of solar radiation, they released oxygen. The concentration of the gas in the atmosphere rose gradually in three stages over a period of 2 billion years.
The blue-green algae covered the earth about 3 billion years ago and is therefore one of the oldest life forms on earth. Cyanobacteria produce energy from sunlight by converting carbon dioxide into oxygen (O2), the first photosynthesis on planet Earth.
The picture shows a stromatolite from the Paleoarchaic (geological era about 3200 to 3600 million years ago) in Western Australia. Stromatolites are sedimentary rocks with embedded sedimentary particles and microorganisms in layered structures, e.g. mats of cyanobacteria (red field).
Picture credits: Stromatolites with cyanobacteria by James St. John, Flickr.com
At that time oxygen was a waste product. The increase of oxygen in the atmosphere led to a massive cooling, climate catastrophe of the earth, called the «Great Oxygen Catastrophe».
In the course of evolution, unicellular organisms, which had a cell nucleus, developed and entered into a symbiosis with cyanobacteria. From this, the first unicellular algae developed about 2.5 billion years ago, they were the only plants on earth. Higher plants developed from the green algae about 500 million years ago until they settled on the land areas of the world.
The consequences of global warming lead to increased algae blooms, especially toxic algae blooms, which multiply explosively. Among other things also the blue-green algae in more extensive regions at the sea coasts, bathing lakes, rivers etc. The rising temperature and increased nutrient inputs from agriculture lead to oxygen depletion in lakes and rivers.
How are blue-green algae formed?
Climate change and the associated global warming with the increase in heat waves will spark the growth of algae in waters. Blue-green algae in particular are much more common in rivers and lakes worldwide. Blue-green algae are present in small quantities in almost every body of water. In most cases they are harmless and are not noticed. However, when it gets nice and hot and sunny, the summer weather offers ideal conditions for the cyanobacteria to multiply.
The increase of nutrients (phosphorus, nitrogen) in the water by sewage treatment plants, fertilizers from agriculture favors the growth of algae and aquatic plants.
As survival artists, blue-green algae have the advantage of being able to store nitrogen in order to survive in the event of a nitrogen deficiency in the water, e.g. at the height of summer when there are also quite a lot of green algae in the water.
Picture credits: Blue-green algae on the water surface by Bobby McKay, Flickr.com
Which blue-green algae (cyanobacteria) are dangerous, toxic?
Which blue-green algae (cyanobacteria) are dangerous, toxic?
In summer, swimming is prohibited at many lakes because of the harmful toxins of blue-green algae.
With its fine stems, the Tychonema bornetii colonizes lake bottoms and spreads relatively easily in the sediments with other filaments of green algae and diatoms, which take advantage of the high concentration of nutrients resting on the lake bottom. The filaments vary in length from 50 or 60 microns to 5 mm. They are threads that move slowly gliding through the water. The image was taken at 400x magnification.
Picture credits: Blue-green algae Tychonema bornetii from Proyecto Agua, Flickr.com
Blue-green algae in water: how dangerous, how to recognize them?
Most cyanobacteria float on the water surface and form green, blue-green, brown or reddish shimmering streaks, depending on the blue-green algae genus. In contrast to green algae, filamentous algae, cyanobacteria are tiny, microscopic and not visible to the eye. Cyanobacteria produce toxins, so-called toxins, which spread in water./p>
Identification characteristics of blue-green algae:
- streaks on the water
- Low water visibility of less than 50cm (no visibility of hands or feet)
- High PH Wert > 9 and oxygensaturation
- Oily green, blue founder coating on the skin
- If swallowed: nausea, respiratory disease, vomiting, diarrhea or limb pain
- Paralysis of the lungs, death by suffocation when swallowing large quantities
- liver damage due to bile acid transport in the liver cells
- On contact with the skin: skin irritation (itching), skin rashes, conjunctivitis and inflammation of the mucous membranes, earache
Ban on bathing with blue-green algae
In order to protect people and animals, general bathing bans and warnings for swimmers, water sports enthusiasts and dog owners due to high concentrations of blue-green algae in infested bathing lakes are increasingly being issued in summer. Warning signs warn against swimming and skin contact with the water, which must be avoided urgently.
Extensive water samples are taken during the bathing season and sent for examination. Only if very low, harmless toxin concentrations are detected in the samples, the bathing bans will be lifted by the environmental office.
General guide and guideline values for the protection of bathers are 2'000 cells per mL as alarm value.
Attracted by the smell of the algae mats, dogs die torturously every year from drinking the water. Especially dogs that enjoy swimming and swallowing water are affected by blue-green algae poisoning. Most poisonings can be treated well if you react quickly and go to the vet. Picture credits W.R.Wagner, Pixelio.
Health problems with blue-green algae
Many of the blue-green algae are harmless to humans, but some produce toxins that are toxic to humans. If swallowed, the toxins enter the body and often cause nausea, diarrhoea and even vomiting.
In case of skin contact, especially with the mucous membrane, inflammations and allergic reactions can be typical characteristics. Neurotoxic effects such as tinnitus, deafness & blindness can occur, as well as neuromuscular blockages up to death by respiratory arrest. Cyanobacterial toxins of microcystins are the most common and damage liver cells as well as the small intestine.
If you repeatedly go into the water, the risk is higher because the body comes into contact with the toxins several times. If the symptoms do not subside, you should not wait any longer and go to the doctor urgently.
Blue-green algae alarm warning signs
The Microcystis, Planktothrix agardhii and Pseudomonas rubescens, Limnothrix redekei, Aphanizomenon f.a. and Anabaena spp. genus of cyanobacteria species form toxins that are dangerous to humans and have led to poisoning and death. (Carmichael & Falconer 1993, Falconer 1993, Kuiper- Goodmann 1997, Pouria et al. 1998).
Causes of blue-green algae, cyanobacteria
Blue-green algae and cyanobacteria are found in small quantities in almost all waters. It becomes problematic when a lot of sunlight and high temperatures warm up the water and the blue-green algae bacteria feel really good and multiply quickly. If nutrients nitrate & phosphates are added, the blue-green algae can multiply explosively. Many bathing lakes are closed in the summer during large heat waves and a blue-green algae alarm is sounded. The water balance or water chemistry is out of balance and excess nutrients are absorbed by the blue-green algae
Why does the water quality tilt in a pond, bathing lake?
The reasons are so varied, here are the most common errors listed:
- Inadequate maintenance and silting up of the pond, water object
- Due to the high solar radiation the water evaporates and warms up quickly
- Fertilisation by fish and feeding
- Nutrients (phosphates, nitrates) from rivers, groundwater (a consequence of eutrophication from agriculture)
Remedy against blue-green algae, cyanobacteria
Avoidance of eutrophication processes such as
- Reduction of nutrient input from diffuse sources
- Fish stocking
- Urine entries
- Spraying lawn fertilizer
- nutrients in groundwater, rivers
- Feeding the waterfowl
- Sediment removal of the sludge layer
Use of the clicking sound technology
With high-precision clicks underwater blue-green algae are put under stress. Successive clicks cause the hollow bodies of the bacterial cell to vibrate permanently.
The resonance oscillations damage the cell walls and hollow bodies of the algae cell and the blue-green algae or cyanobacteria die quite naturally.
A natural, successful blue-green algae control is achieved with the G-Sonic Algenfrei device. The devices combat all types of algae brown algae, green algae, floating algae, thread algae in fresh water effectively and in the long term.