Context:
2014-2016 Pacific marine heatwave wiped out four million of Alaska’s seabirds.
Marine Heat Waves (MHWs):
- Extreme weather events where the sea surface temperature in a specific region rises 3-4°C above the average for at least 5 days.
- Last from weeks to years.
- Main Drivers –
- Surface Heat Flux – Caused by atmospheric heating, often due to prolonged high-pressure systems over a water region.
- Advection – Movement of warmer waters into the region by ocean currents.
- Impacts –
- Ecosystem Disruption – Mass mortality of habitat-forming species like kelps and corals, affecting ecosystem productivity.
- Species Impact – Reduced reproductive success, increased mortality, and mass die-offs in upper-trophic-level species.
- Shifting Species – Native species migrate to cooler waters, while invasive species like sea urchins and jellyfish thrive.
- Toxic Blooms – Higher temperatures and deoxygenation can lead to toxic algal blooms.
- Extreme Weather – Contribute to extreme weather events like tropical storms and hurricanes.
Read more about Heat Waves in India, Heat Action Plan, Heat Index
Source: TH
Previous Year Question
Consider the following statements:
Statement-I: The temperature contrast between continents and oceans is greater during summer than in winter.
Statement-II: The specific heat of water is more than that of land surface.
Which one of the following is correct in respect of the above statements?
[UPSC Civil Services Exam – 2023 Prelims]
(a) Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I
(b) Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I
(c) Statement-I is correct but Statement-II is incorrect
(d) Statement-I is incorrect but Statement-II is correct
Answer: (a)