Despite the ongoing marine heat waves, coral bleaching was only observed in May this year, prompting experts from KUFOS to conduct a detailed field study. If the current high heat levels persist in the months ahead, the bleaching could eventually lead to the death of the corals. According to the study, this would significantly jeopardise the delicate ecological balance of Lakshadweep, underscoring the urgent need for immediate conservation efforts.

Under the leadership of Anu Gopinath, head of Chemical Oceanography in the Department of Aquatic Environment Management, the team said the coral bleaching event in the Lakshadweep Sea is unprecedented. Previous coral bleaching events occurred in 1998, 2010, and 2015.

Coral reefs in Lakshadweep are vital for several reasons. They support diverse marine life, including fish, invertebrates, and algae. The reefs act as natural barriers, protecting shorelines from erosion and storm surges. Local communities rely on reef-associated fish for sustenance and livelihood. Furthermore, the reefs attract tourists, contributing to the local economy.

Kavaratti-based scientist Idrees Babu KK, who works with the science and technology department in the union territory, ratified the study's findings. His department's latest survey conducted at Kavaratti atoll found that the extent of bleaching was 84.6 %, with mass bleaching observed in and around the atolls. "The recent event is considered one of the worst compared to previous years (1998: 81%, 2010: 65%, 2020: 41.9%)," he said.

Gopinath explained that rising sea surface temperatures, attributed to global warming, have worsened the frequency and severity of bleaching events in this area. She also mentioned that the areas most affected are the coral reefs of atolls and lagoons, followed by outer reef flats and slopes.

Tiny organisms that congregate to form reefs and islands create coral reefs.

"Many corals live in large colonies and have a symbiotic relationship with microscopic algae called zooxanthellae, which live in their tissues. When the water temperature rises, the corals expel the zooxanthellae, leading to bleaching. A change in the coral reef's colour to yellow is a visual representation of this, and it can cause widespread coral die-offs," Gopinath explained.

Coral reefs worldwide are dying due to global warming. When sea surface temperatures rise 1 degree Celsius above the average, corals experience thermal stress, which becomes more severe with prolonged exposure to high temperatures.

Most of Lakshadweep's islands are coral atolls. Since the coral islands are inhabited, the destruction will impact their lives and livelihoods. In addition, the rising sea levels caused by climate change pose another threat to the communities.

When the water is too warm, corals expel the microscopic algae (zooxanthellae) in their tissues. These algae produce food for the corals. Without the algae, the corals' tissues become transparent, exposing their white skeleton. This is known as coral bleaching.

"Most coral reefs appear in shades of brown. The fluorescent pink colour on their tips adds to their magical charm. It's a spectacular sight to behold the vast colonies of corals in the pristine waters in the company of psychedelic-coloured marine fishes that swish and sway through them," said Gopinath.

White, according to Gopinath, is the colour of death for corals. When they bleach, they turn white. They slowly break apart from clusters and disintegrate into small pieces to be washed ashore. The team surveyed five islands and found huge quantities of dead corals washed ashore on all of them, Gopinath said.

A 2022 study by the Indian Institute of Tropical Meteorology (IITM) in Pune, said marine heatwaves are rising in the Indian Ocean. The study, which Roxy Mathew Koll led and appeared in the journal JGR Oceans, showed a significant increase due to the Indian Ocean's rapid warming and powerful El Nio events.

Heat waves are threatening the livelihoods of coastal communities, tourism and fisheries sectors, and critical marine habitats, including seagrass meadows. Similar to corals, seagrass meadows and kelp forests have also experienced harmful impacts from the heat waves, such as impaired photosynthesis, reduced growth, and hindered reproductive functions.

Arya P. Kumar, a member of the KUFOS research team, reported that nearly 70% of the coral reef area in the Lakshadweep islands has experienced bleaching. The total coral area of the islands is estimated to be around 30,000 sq. km. Kumar mentioned that fast-growing and branching corals such as Acropora and Pocillopora are particularly susceptible to bleaching in the Lakshadweep seas. Widespread bleaching was observed around the Kavarathi and Suheli islands.

Researchers have identified 178 species of corals in the waters of Lakshadweep. The most notable are the Pocillopora, also known as cauliflower corals due to their resemblance to the vegetable. They stand out with striking colours, ranging from green, pink, and yellowish-brown to pale brown.

R. Dhinesh, a researcher, stated that anthropogenic activities also contribute to coral bleaching. Large amounts of plastic waste have been observed on the shores of the uninhabited island of Suheli. Additionally, microplastics were found in the water and sediment samples, and traces of pesticides were detected.

Gopinath said El Nino, the climatic process that leads to an increase in sea surface temperatures in the central and eastern tropical Pacific, is the major villain behind coral bleaching.

"The death of the corals could have a disastrous effect, potentially leading to the collapse of the marine ecosystem," she warned. It may take several years for the corals to recover.