01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-04-0340 |
| Title of Abstract | Influence of Subsurface Heat Storage on Coral Thermal Stress Across ENSO Phases in the Lakshadweep Sea |
| Authors | Nanda Kishore*, Shelton Padua, Vineetha Gopinath, Ratheesh Kumar R, Grinson George |
| Organisation | ICAR-Central Marine Fisheries Research Institute |
| Address | Mannarkunnumel(H), Kanjirakkad, Perumbavoor Ernakulam, Kerala, India Pincode: 683543 E-mail: nandakishoree1995@gmail.com |
| Country | India |
| Presentation | Poster |
| Abstract | Coral reef ecosystems are highly vulnerable to thermal stress, which often leads to widespread bleaching events. While surface temperature-based metrics such as Degree Heating Weeks (DHW) are commonly used to assess bleaching risk, subsurface heat storage within the upper ocean can significantly influence the persistence of thermal stress. Understanding the interaction between these components, particularly under climate variability drivers like the El Niño⿿Southern Oscillation (ENSO), is essential for improving risk assessments. In this study, we investigate the relationship between DHW, maximum Sea Surface Temperature (SST), and upper 50 m Ocean Heat Content (OHC) in the Lakshadweep region over a 20-year period (2000⿿2020), focusing on their variability across ENSO phases. Results indicate that severe thermal stress (DHW > 4 °C-weeks) predominantly occurred during La Niña events, the cool phase of ENSO. On the other hand, El Niño years the warm phase of ENSO usually has high SST maxima but comparatively lower DHW values. Ongoing analysis of OHC anomalies suggests that prolonged subsurface heat accumulation may significantly influence the persistence of thermal stress during El Niño events, even when surface warming is short-lived. These findings demonstrate that DHW variability is not solely governed by SST maxima but is also modulated by subsurface thermal dynamics, which vary across ENSO phases. Understanding these interactions provides critical insights into the mechanisms driving coral heat stress and highlights the need to integrate subsurface ocean processes into predictive frameworks for coral reef resilience under a changing climate. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Coral bleaching, Degree Heating Weeks (DHW), Sea Surface Temperature (SST), Ocean Heat Content (OHC), ENSO phases, La Niña, El Niño |
| For Awards | no |