The sudden color change of Manila Bay’s waters from dark blue to turquoise blue in 2020 was caused by increased pollution emanating from Bacoor Bay and Pasig River, the Philippine Space Agency (PhilSA) disclosed, Thursday, Nov. 18.

On its official page, the Philippine Space Agency looked back on the discoloration of Manila Bay’s waters that took place on March 25, 2020, a week after the Luzon-wide enhanced community quarantine (ECQ) took place.

The bright turquoise waters of Manila Bay stirred the news and social media last year, leaving unanswered queries.

PhilSA recalled the reason behind the phenomenon during the observance of the Environmental Awareness Month.

"Using spaceborne images, researchers were able to estimate the chlorophyll-a concentration and water turbidity in the area from March 13 to March 28. High water turbidity could indicate high water pollution while chlorophyll-a suggests algal abundance," the agency said.

PhilSA also said that based on satellite images, high chlorophyll-a and turbidity values were already observed as early as March 23, with turbidity levels doubling up by March 25, suggesting that the discoloration of Manila Bay may have been caused by high water pollution.

"However, since chlorophyll-a levels did not increase significantly around Manila Bay, the change could not be attributed to algal bloom," it added.

The agency explained that the main "hotspots" were Pasig River and Bacoor Bay. Depending on the wind direction and water circulation, the waters from the aforementioned areas may have influenced the waters in Manila Bay.

The pollutants from Bacoor Bay were mainly from the aquaculture industry and commercial establishments while those from Pasig River were collective wastes from commercial, industrial, and residential activities, it also pointed.

"Significant decline in chlorophyll-a and turbidity was already observed by March 28,," PhilSA assured the public. (Charie Mae F. Abarca)