Baseline Survey on Coral Diseases, Stress Factors and New Threats in Coral Reefs of Gulf of Mannar Marine Biosphere, India

Gulf of Mannar Marine Biosphere Reserve (GOMMBRE) is the first marine biosphere reserve in India and Southeast Asia. It has a rich marine biodiversity including coral reefs, but now facing threats from different environmental factors and anthropogenic interferences. Particularly, coral reefs distributed in the 21 islands under the Gulf of Mannar (GoM) region are facing critical threats. Although several institutions and authors have studied various aspects on corals, direct and indirect influences of natural and anthropogenic catastrophes on corals have been poorly understood. Therefore, the main objective of this study was to identify the anthropogenic disturbances, biological stress factors and diseases on fringing reefs of GoM. The present study reveals that dead coral reefs are being replaced by assemblage of marine algae. Although several diseases were recorded during this study, pink line disease is wide spread in all the islands. Porites sp. and Acropora sp. were the more affected corals. This baseline data lays foundations to survey and to assess the rapid changes that occur over a period of time in coral reefs of GoM.

Exhibition of Bleaching Resistance Via Adaptive Bleaching Pattern by Coral Reefs of the Gulf of Mannar during Massive Bleaching Event 2019

Coral reefs in the Gulf of Mannar(GoM)and Palk Bay regions are facing potential threats from climate change,sedimentation and anthropogenic activities.Considerably,coral reefs in these two regions are highly damaged due to frequent bleaching events caused by increased sea surface temperature(SST)recorded over the past two decades.Recently,during February to May 2019,mass bleaching event of corals was documented again in GoM and Palk Bay regions due to increased sea surface temperatures ranged between 32°C to 36°C.Despite of completely bleached corals,some coral colonies of the same bleached coral species have displayed adaptive bleaching pattern(ABP)for survival.This incidence is displayed by the symbiotic zooxanthellae to protect coral polyps from environmental stress such as elevated temperatures.These observations infer that coral colonies with preferential bleaching pattern ability would serve as environmental stress resisting coral colonies which can be used for restoration activities and cryopreservation.Further studies are needed to explain the potential mechanisms or specific environmental drivers responsible for ABP.