May 4, 2024

Lukmaan IAS

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RESILIENCE OF CORAL REEFS IN THE FACE OF CLIMATE CHANGE

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TAG: GS 3: ECOLOGY AND ENVIRONMENT

THE CONTEXT: The study conducted by the Australian Institute of Marine Science (AIMS) sheds light on the remarkable resilience of coral reefs, particularly focusing on the remote Scott Reefs in northwest Australia.

EXPLANATION:

  • Spanning over three decades, the research encompasses various disturbances including cyclones and mass bleaching events triggered by marine heatwaves.
  • By analyzing long-term data, researchers delineate cycles of collapse and recovery within coral populations, elucidating the critical role of time in facilitating reef regeneration.

Resilience and Recovery Dynamics

  • Findings from the study underscore the intrinsic capacity of coral ecosystems to rebound from disturbances, exemplified by the observed patterns of coral regeneration following bleaching events.
  • An Australian Institute of Marine Science (AIMS) coral scientist emphasizes the importance of temporal intervals between disturbances for facilitating recovery.
  • However, the study warns that recurrent and frequent disturbances, as projected in future climate scenarios, pose a grave threat to coral resilience, potentially leading to ecosystem collapse.

Genetic Diversity as a Buffer

  • Genetic analyses conducted as part of the research reveal that coral diversity remains intact over time, a crucial factor in bolstering resilience against climate change.
  • The significance of genetic diversity in fueling adaptation and enhancing the ability of coral reefs to withstand environmental stressors has been highlighted.
  • The study underscores the importance of preserving genetic diversity, especially in remote reef systems like Scott Reefs, to sustain healthy coral populations and promote long-term resilience.

Implications for Larger Reef Systems

  • The insights gleaned from the study hold broader implications for coral reef ecosystems worldwide, including the iconic Great Barrier Reef.
  • By elucidating fundamental ecological processes and evolutionary dynamics, the research offers valuable lessons that can inform conservation and management strategies for larger reef systems.
  • The relevance of understanding resilience mechanisms in isolated reef ecosystems like Scott Reefs has been emphasized, which serve as microcosms for studying broader reef dynamics and informing conservation efforts.

Challenges and Future Projections

  • Despite the current resilience demonstrated by coral reefs, the study underscores the looming threat posed by climate change-induced disturbances.
  • There are challenges posed by recurrent mass bleaching events, exacerbated by factors such as El Niño conditions and climate change.
  • While Western Australia’s coral reefs presently exhibit robust health, the long-term prognosis remains uncertain in the face of escalating climate-related pressures.

Corals and Coral Bleaching

  • Coral reefs are vital ecosystems built by coral polyps, which have a symbiotic relationship with zooxanthellae algae.
  • When water temperatures rise, corals expel these algae, leading to bleaching—a phenomenon where corals lose their vibrant colors and eventually die.
  • Ocean acidification exacerbates bleaching by reducing calcium mineral availability for coral exoskeletons.

Types of coral reefs in India:

  • Fringing reefs
    • Fringing reefs evolve and develop near the continent and remain close to the coastline. These reefs are separated from the coastline by small, shallow lagoons. They are the most commonly found reefs in the world.
  • Barrier reefs
    • Barrier reefs are found offshore on the continental shelf. They usually run parallel to the coastline at some distance. A deep and wide lagoon is located between the coastline and the barrier reef.
  • Atolls
    • Atolls are formed on mid-oceanic ridges. They are shaped circularly or elliptically and are surrounded by seas on all four sides and have shallow waters in the center called a lagoon.
  • All the three major reef types occur in India. The mainland coast of India has two widely separated areas containing reefs: the Gulf of Kachchh in the northwest, which has some of the most northerly reefs in the world, and Palk Bay and Gulf of Mannar in the southeast.
  • In addition to these, there are patches of reef growth on the West Coast, for example, coral reefs at Malvan.
  • The Andaman and Nicobar Islands have fringing reefs around many islands, and a long barrier reef (329 km) on the west coast.
  • Little is known about these reefs, which may be the most diverse and pristine reefs in India. The Lakshadweep also has extensive reefs but these are also poorly explored.

Impact of Climate Change on Coral Reefs

  • Global warming has resulted in widespread coral bleaching events, causing significant damage to coral reefs worldwide.
  • The loss of coral reefs has severe repercussions for coastal communities, including those inhabiting coral islands like Lakshadweep, who rely on these ecosystems for livelihoods and protection from rising sea levels.

SOURCE: https://phys.org/news/2024-04-corals.html#google_vignette

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