learn only 3 things about them ...
They can undergo photosynthesis, but are more similar
to bacteria than algae.
They include some of the oldest living fossils: those
are the reason why wild flamingos are pink!
are cyanobacteria? Cyanobacteria
are microscopic organisms that live in water and can undergo photosynthesis.
Although they are sometimes called blue-green algae, they are not
related to algae. They are classified with bacteria because these
organisms share similar features with bacteria.
Cyanobacteria are more abundant in the intertidal zone than in the
open ocean. They are also found in soil and freshwater, and some even
live inside rocks. They are also found in extreme conditions such
as hot springs and snowfields.
Where seen? On our shores, cyanobacteria
can be seen growing on rocks as well as on sandy shores among seagrasses
and seaweeds. 90 species of cyanobacteria are recorded for Singapore
by Pham (link below). Some live inside other animals such as sponges
like Lamellodysidea herbacea.
Features: They have a bluish pigment
phycocyanin that is used to capture light for photosynthesis. They
also contain chlorophyll.
Big bacteria: These microscopic organisms sometimes can
aggregate to produce structures large enough for us to see and feel.
These can appear as blobs on rocks, or fine hair-like filaments on
rocks and among seaweeds and seagrasses, sometimes forming mats. On
land, they may look like slime or scum. They are not always blue or
green. Some can be black, brown or red.
Bacteria reefs: Although tiny,
these organisms can have a large impact on the environment. Cyanobacteria
produced stromatolites, the oldest living fossils, dating 3 billion
years. Stromatolites are large, hard structures of laminated calcium
or silica. Some cyanobacteria continue to produce stromatolites today
in tropical Australia and the Bahamas. These large structures are
produced by microscopic animals so a stromatolite 1m tall may be 2,000
years old! The chloroplast which plants use to undergo photosynthesis
and make food, is actually a cyanobacterium living inside the plant's
cell! It is believed that the oxygen atmosphere we breathe was generated
by cyanobacteria in prehistoric times. Cyanobacteria were the dominant
lifeform on Earth 2 billion years ago.
Today, cyanobacteria continue to have an impact. The Red Sea is named
for the red colour of cyanobacteria Oscillatoria that produce
dense blooms in that body of water. African flamingos are pink from
eating a kind of red cyanobacteria Sirulina. Some species of
cyanobacteria can fix atmospheric nitrogen for their own needs. Some
of these are believed to benefit seagrasses by fixing nitrogen for
Role in the habitat: Cyanobacteria
are eaten by a wide range of animals. Among the common animals believed
to eat cyanobacteria are sea slugs like the Hairy
sea hare (Bursatella leachii) and Long-tailed
hairy sea hare (Styloceilus sp.)
Human uses: Some species of cyanobacteria
are able to breakdown heavy hydrocarbons and may thus have a practical
use in cleaning up oil spills. The nitrogen-fixing properties of cyanobacteria
are believed to be important to the fertility of ride padi fields.
On the other hand, blooms of cyanobacteria in nutrient rich waters
(e.g., polluted by agricultural drainage or sewage) can produce toxins
that poison the water.
St. John's Island, May 05
Lazarus Island, Dec 06
Growing among and on seagrasses
Cyrene Reef, Aug 10
Pulau Semakau, Apr 08
Sentosa, Jul 08
Sisters Island, Feb 08
Lazarus Island, Aug 12
Changi, Jun 10
Pulau Senang, Jun 10
|Cyanobacteria on Singapore shores
- Lee Ai Chin, Iris U. Baula, Lilibeth N. Miranda and Sin Tsai Min ; editors: Sin Tsai Min and Wang Luan Keng, A photographic guide to the marine algae of Singapore, 2015. Tropical Marine Science Institute, 201 pp.
- Pham, M.
N., H. T. W. Tan, S. Mitrovic & H. H. T. Yeo, 2011. A
Checklist of the Algae of Singapore, 2nd Edition. Lee Kong Chian Natural History Museum, National University of Singapore,
Singapore. 99 pp. Uploaded 1 October 2011. [PDF, 1.58 MB].
- Lim, S.,
P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The
Life and Times of Labrador Beach. Division of Biology, School
of Science, Nanyang Technological University & Department
of Zoology, the National University of Singapore. 160 pp.
- Sumich, James
L. 1999. An
Introduction to the Biology of Marine Life
7th ed., WCB/McGraw-Hill. 484 pp.
- Bell, Peter
R. and Hemsley, Alan R. 2000. Green
Plants: Their Origin and Diversity
2nd edition. Cambridge University Press. 349 pp.