Southern Ocean Marine Heat Waves Disrupt Whale and Seabird Movements
UPSC / SSC current affairs note · IR
Why in news
Recent reports indicate a 60% drop in humpback whale sightings off Western Australia and the appearance of weakened Southern Ocean seabirds on Australia's east coast, suggesting that marine heat waves are disrupting ocean ecosystems. These events highlight the urgent need for better monitoring of changing ocean conditions.
Background
The Southern Ocean is typically one of the coldest marine environments, but it is experiencing warming. Marine heat waves, such as 'the Blob' in the North Pacific (2014-2016), have previously caused major ecological damage. The current heat waves around Heard Island and McDonald Islands and in the southern Tasman Sea are among the fastest-warming regions.
Key facts
In late June, humpback whale sightings in southwest Western Australia fell by about 60% below normal during their migration north.
A week later, rare albatrosses and petrels appeared on Australia's east coast, thousands of kilometres from their usual Southern Ocean feeding grounds, many in poor condition.
A persistent marine heat wave has affected waters around Heard Island and McDonald Islands since February, extending to Antarctica's sea ice edge.
Another marine heat wave has lingered in the southern Tasman Sea since at least April.
These regions are among the fastest-warming ocean areas on the planet.
Marine heat waves can disrupt food webs and cause predators to follow prey or move to unusual areas.
The events suggest changing ocean conditions may be pushing marine life off course.
Limited monitoring hinders understanding of these significant ecosystem shifts.
Better long-term data is needed to track accelerating changes in the Southern Ocean.
Prelims pointers
- Southern Ocean: surrounds Antarctica, coldest marine environment.
- Marine heat wave: prolonged period of unusually warm ocean temperatures.
- Heard Island and McDonald Islands: Australian external territory, sub-Antarctic.
- Tasman Sea: between Australia and New Zealand.
- Humpback whale: a species of baleen whale known for migration.
- Albatrosses and petrels: seabirds that forage in Southern Ocean.
- The Blob: marine heat wave in North Pacific (2014-2016).
Mains angles
- Discuss the impact of marine heat waves on marine ecosystems and biodiversity.
- Examine the role of ocean monitoring and data collection in understanding climate change effects.
- Analyse the implications of changing marine species distribution for conservation and fisheries.