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https://theconversation.com/ocean-heat-is-changing-marine-food-webs-with-far-reaching-consequences-for-nz-fisheries-and-sea-life-236427>
"The global ocean continues to warm at a concerning rate.
Satellite measurements of average sea surface temperatures show February this
year was the highest for any month in the 45-year dataset, and the warming
trend continued in May.
New Zealand’s sea temperatures are also hitting record highs. Between 2022 and
2023, oceanic and coastal waters reached their warmest annual temperatures
since measurements began in 1982, according to Stats NZ data.
This warming is already threatening coral reefs – the Great Barrier Reef is the
hottest it’s been in 400 years – and marine life. But it is also reshaping
ecosystems at the very basis of ocean food webs.
Microscopic algae, or phytoplankton, are ubiquitous in the surface layers of
the ocean. They represent the foundation of the marine food web and serve as a
substantial carbon sink.
Each day, they take up more than a hundred million tonnes of carbon dioxide
through photosynthesis. The carbon then either sinks to the bottom of the ocean
as the microalgae dies off or is “fixed” in tiny animals that graze on the
plants.
Already, scientists are observing a downward trend in this ocean production,
leading to expanding “ocean deserts” and the depletion of beneficial microalgae
in favour of harmful algal blooms.
Unless we act to cut emissions, these shifts in microalgal composition are
projected to get worse as ocean temperatures continue to rise, globally and
regionally in the waters off Aotearoa New Zealand."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
