CHANGE IN MONSOON AFFECTS
MARINE LIFE : ENVIRONMENT
NEWS: Changes in monsoon affect marine productivity
in Bay of Bengal
WHAT’S IN THE NEWS?
A 22,000-year study shows that
extreme Indian Summer Monsoon events disrupt nutrient upwelling in the Bay of
Bengal, cutting plankton productivity by up to 50%. This poses a serious threat
to food security and marine biodiversity in one of the world’s most
fishery-rich yet vulnerable ocean zones.
Introduction to the Study
- Published
in: Nature Geoscience – a prestigious
peer-reviewed journal.
- Research
Collaboration: Conducted by an international team including
scientists from India, China, Europe, and the U.S., with major
contributions from the University of Texas at Austin and Rutgers
University.
- Focus
of Study: Reconstructs 22,000 years of Indian Summer
Monsoon variability and its direct impact on plankton growth in
the Bay of Bengal (BoB).
- Significance:
Establishes a link between climate variability and marine ecosystem
health, providing long-term insight into oceanic productivity.
- Relevance
for UPSC GS3: Environment, Climate Change, and Food Security.
Key Scientific Findings
- Monsoon-Driven
Marine Productivity:
- The intensity
of the Indian Summer Monsoon has a direct influence on plankton
productivity.
- Plankton
(especially phytoplankton) is a foundational part of the marine food web
and crucial for fisheries and ocean biodiversity.
- Disruption
by Monsoon Extremes:
- Both very
strong and very weak monsoons negatively impact vertical mixing of
ocean water.
- Nutrient
upwelling from deeper layers gets suppressed, reducing the
availability of nutrients in the upper layers where plankton thrive.
- Result:
Up to 50% decline in plankton availability, affecting the entire
marine ecosystem.
- Sediment-Based
Climate Reconstruction:
- Researchers
analysed marine sediment cores for chemical signatures to
reconstruct past ocean temperatures, monsoon strength, and biological
productivity.
- Provides
a paleo-climatic timeline of changes in BoB’s marine ecosystem
over the past 22,000 years.
- Modern
Parallels and Climate Change Risk:
- Present-day
climate data mirrors patterns of disruption seen in the past.
- Suggests
that human-induced climate change (e.g., global warming, altered
monsoon patterns) may destabilize BoB’s ecosystem in the near
future.
- Warns
of a potential climate tipping point for fisheries and marine
health.
Ecological and Socio-Economic
Implications
- Millions
of coastal communities in India, Bangladesh, Myanmar, and Sri Lanka
depend on BoB fisheries for dietary protein and livelihoods.
- A
decline in plankton affects fish populations, directly impacting nutrition
and employment.
- High
Output, High Vulnerability Zone:
- Although
BoB makes up <1% of global ocean area, it contributes ~8% of
the world’s fishery output.
- This
makes it disproportionately productive but also highly
sensitive to environmental changes.
- Impact
on Biodiversity and Trophic Levels:
- Disruption
in plankton growth affects higher trophic levels (zooplankton,
fish, marine mammals).
- Potential
to trigger cascading effects across the food chain.
- The
findings underscore the need for climate-resilient marine policies,
adaptive fisheries management, and sustainable coastal
development.
- It
also calls for integrating climate modeling into marine
ecosystem governance.
Source: https://www.thehindu.com/sci-tech/energy-and-environment/changes-in-monsoon-strength-affects-marine-productivity-in-bay-of-bengal/article69503841.ece