
Photo taken on March 29, 2021 shows red tide at a beach in Pula, Croatia. Red tide is a burst of harmful algae growth which can turn ocean water red, brown or green. (Srecko Niketic/Pixsell via Xinhua)

Photo taken on March 29, 2021 shows red tide at a beach in Pula, Croatia. Red tide is a burst of harmful algae growth which can turn ocean water red, brown or green. (Srecko Niketic/Pixsell via Xinhua)

Photo taken on March 29, 2021 shows red tide at a beach in Pula, Croatia. Red tide is a burst of harmful algae growth which can turn ocean water red, brown or green. (Srecko Niketic/Pixsell via Xinhua)