Read the following passage and answer the questions given after it.

First, thousands of flamingos coloured the Talawe wetlands near NRI Complex in Navi Mumbai pink during the lockdown, their numbers bolstered by the sheer lack of human activity. Now, the water in part of the wetland itself has turned pink, probably due to an explosive blooming of red algae that thrives in saline water, especially as the summer picks up and the wetland loses water.

The deep pink water, located towards the south-eastern end of the wetland, was spotted on 14 May 2020. The pink water was not there till late last week. The bloom has been identified as a rare and first-of-its-kind occurrence for Mumbai Metropolitan Region by Bombay Natural History Society (BNHS) that plans to take samples of the water for study. However, a local resident, Seema Tania from NRI Complex, Seawoods, said she had spotted the pink wash across a much larger area at the same creek in 2016.“Almost 500-600m patch of the creek turned bright pink and we thought chemicals had been dumped in the creek,” she said.

BNHS and independent microbiologists presume that the colour is from microscopic algae. “Owing to high salinity in the area, it looks like an algal bloom. Our researchers have never witnessed something like this along Mumbai’s creeks,” said Deepak Apte, director, BNHS. “Around the world, such a phenomena has been observed regularly with red algae but it has to be investigated how it has appeared along the Mumbai creek.”

Flamingos are known to feed on this algae, crustaceans, shrimp, and aquatic plants, which gives them the pink colour, said Apte. Dr P Sathiyaselvam, assistant director (wetland conservation), BNHS said, “This is clearly an algal bloom. We have observed the same at the northern portion of Chilika Lake (in Odisha) during early winter months over the years, and also towards the northern end of wetlands in Thoothukudi in Tamil Nadu.” “This is a natural phenomenon. Vigorous growth of algae or bacteria having beta-carotene gives this type of characteristic colouration to the water. It is also related to increased evaporation, salinity, and the current hot and humid weather conditions,” said Rahul Khot, assistant director (in-charge of the flamingo monitoring program).

Ornithologist, naturalist and writer Sunjoy Monga said a similar discolouration of water with a pink hue was witnessed at a flamingo habitat in Porbandar in May 2007. “This happened at the edges of the creek cramped with flamingos with high salinity displaying a pinkish maroon wash to it.” A similar example of what has been observed in Navi Mumbai was recently witnessed across a massive stretch at the Edgars Creek in Melbourne, Australia, that started on 10 Mayand intensified subsequently. The source of the pink water is being investigated, the Epoch Times reported. Other examples of changing water colour to pink across a much larger area has been observed at Cameron Falls in Waterton Lakes National Park, Canada and the Dead Sea, a salt lake between Israel and Jordan, to name a few.

The main theme of the passage is:

why the water in some parts of Mumbai wetland has turned pink