Question

Cyanobacteria are
(a)Saprotrophs
(b)Photoautotrophs
(c)Chemotrophs
(d)Chemoheterotrophs

Answer 1

Hint: Cyanobacteria are believed to be the ancestors of green plants. They were fundamentally important in Earth history, as primary producers, and on the progressive atmospheric oxygenation. They comprise around 2000 species, with a wide variety of shapes and sizes, in 150 genera.

Complete answer:
-Oxygen-evolving, plant-like photosynthesis is carried out by Cyanobacteria.
-The two main evolutionary contributions made by cyanobacteria are the oxygen-rich atmosphere of the Earth and the cyanobacterial origin of plastids in plants.
-In most inland waters, cyanobacteria (also called blue-green algae) are an ancient group of photosynthetic microbes that can have a significant influence on the quality of water and the functioning of aquatic ecosystems.

Additional Information: -Ecologically, mat-formers that form polysaccharide-rich crusts, films, and thicker layers over rocks, sediments, and these are the three most critical classes of cyanobacteria found in inland waters; bloom-formers that occur in eutrophic lakes and cause disturbance of the food web as well as develop toxins and surface scums; and picocyanobacteria, minute organisms that are often the main photosynthetic organisms.
-BGA monitoring is critical because it poses a significant threat to the quality of water, the stability of the environment, the availability of surface drinking water, and public health by generating toxins and the large biomass produced in algal blooms.
-They have specialized cells for nitrogen fixation (heterocysts) and resting cells able to endure environmental stress (akinetes).
So, the correct answer is ‘Photoautotrophs’.

Note: -Several species of cyanobacteria in inland water are harvested or grown as food sources, animal feed, fertilizers, and health items.
-Excess nitrogen and carbon in water can be reduced by BGA, but dissolved oxygen can also be depleted when overabundant.