Description

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Context:

Nearly 20 per cent of species found in 21 of 51 UNESCO World Heritage marine sites have reached or exceeded their living thermal limits.

Key Findings:

Affected Species	Total Threatened Species: 881 out of 4,406 mapped.
	Fish: 342 species.
	Algae: 135 species.
	Molluscs: 76 species.
	Mammals: Bottlenose dolphin, West Indian manatee, elephant seal, right whale, crabeater seal.
	Sharks: Sandbar shark, whitetip stingray, Caribbean reef shark, southern stingray, Krefft's stingray, lemon shark, yellow stingray.
Temperature Limit Hotspots	Belize Barrier Reef: 53% of species live near their temperature limits.
	Coiba National Park (Panama): 26.6% of threatened species.
	Everglades National Park (USA): 24.4% of endangered species.
	Banc d'Arguin National Park (Mauritania): 23.9% of threatened species.
	Sundarbans (Bay of Bengal): 19.8% of species living beyond temperature limits.
Ocean Heat Trends	Global SST Increase: 1°C higher than 140 years ago.
	Ocean Heat Content: All six major oceans have been affected since 1998.
	Southern Ocean: Most significant warming observed since 1998.
Consequences of Ocean Warming
Adaptation or Migration	Species may migrate to colder waters but may struggle to adapt effectively.
	Tropical species are particularly vulnerable due to limited exposure to high temperatures.
Reproductive Stress	Warm waters impair reproductive rates (e.g., female sperm whales struggle to conceive).
	Rising stress levels in marine mammals reduce survival rates.
Food Chain Disruption	Species like North Atlantic right whales face food shortages as prey migrates.
	Key habitats for fish, lobsters, oysters, and crabs are changing.
Oxygen and Nutrient Cycle	Changes in water movement reduce oxygen levels and nutrient circulation.
	Altered bacterial behavior affects water and atmospheric properties.
Pathogen Vulnerability	Migrating species face exposure to new pathogens, increasing disease risks.

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PRACTICE QUESTION

Q.Discuss the implications of this phenomenon on marine biodiversity and the effectiveness of global conservation efforts. Also, evaluate the role of international agreements like the Paris Climate Accord in addressing the threats posed to marine ecosystems. (250 words)