New Zealand's oceanic, coastal water temperatures highest since 1982-Xinhua

New Zealand's oceanic, coastal water temperatures highest since 1982

Source: Xinhua

Editor: huaxia

2024-07-09 10:41:01

WELLINGTON, July 9 (Xinhua) -- Oceanic and coastal waters around New Zealand reached the warmest annual temperatures between 2022 and 2023, since the statistics department Stats NZ started to collect data for the series in 1982.

Each oceanic and coastal region in New Zealand experienced their hottest years ever recorded in either 2022 or 2023, Stats NZ said on Tuesday.

"Even small rises in temperature can disrupt marine ecosystems, cause some species to relocate, and increase disease risks," Stats NZ environment and agricultural statistics senior manager Stuart Jones said.

It also contributed to sea-level rise as the warmer water expands, Jones said.

Since 1982, sea-surface temperatures increased by 0.63 to 1.05 degree Celsius during the recorded period across New Zealand's oceanic regions, with the Tasman Sea having the highest average rate, Stats NZ said.

Coastal regions warmed by 0.74 to 1.35 degrees Celsius during the recorded period, with East Coast South Island having the highest average rate, Jones said, adding measuring sea-surface temperature shows how rapidly the ocean's uppermost productive layers are warming.

Marine heatwaves, which means prolonged periods of unusual seawater warmth, also reached new levels, Stats NZ said.

The Tasman Sea spent 61 percent of the 2022 year in a marine heatwave, the highest among oceanic regions, Jones said, adding Western North Island experienced heatwave conditions for 89 percent of the year, the highest among coastal regions.

Warming seas can influence primary production through the generation of organic matter by phytoplankton, or microscopic algae, which supports the marine food chain, he said.

In the ocean surrounding New Zealand, between 1998 and 2022, marine primary productivity has tended to decrease with rising sea temperature in the warmer northern waters, while increasing with rising sea temperature in the cooler southern waters, he added.