https://phys.org/news/2025-05-climate-coastal-lagoons-salty-soup.html
'The impacts of human activity and climate change are coalescing to make
coastal lagoons saltier, changing the microbial life they support and the
function they play in their ecosystems, according to new University of Adelaide
research published in the journal
Earth-Science Reviews.
Coastal lagoons are critical ecosystems that provide essential habitats and
ecosystem services, including carbon sequestration, nutrient cycling, and
fisheries support.
"Under normal conditions, lagoons act as nurseries for fish and crustaceans,
they are internationally important feeding grounds for migratory birds, and
they protect coasts from storm surges," says the university's Dr. Chris
Keneally. "Their microbial makeup is what makes this happen, recycling
nutrients and fostering this high productivity, allowing diverse plant and
animal life to flourish.
"However, a single hot, dry summer, like the one we have recently experienced,
can completely shift this important habitat into a salty, green soup, leading
to the microbes becoming less diverse and those that are salt-tolerant becoming
more dominant. Key processes, such as nitrification, denitrification, and
carbon cycling are then disrupted, altering nutrient retention, organic matter
decomposition, and greenhouse gas emissions."
The trend of hypersalinity in coastal lagoons is global, occurring most often
in arid and semi-arid coastal lagoons, such as those in Australia, the
Mediterranean and the Persian Gulf. The phenomenon has accelerated in Australia
over the last 40 years.
"The rise in salinity can be attributed to elevated temperatures, enhanced
evaporation, reduced rain and freshwater inputs, and rising sea levels," says
Dr. Keneally. "Human factors such as upstream water diversions, urbanization
and development, and groundwater depletion also reduce freshwater inflow to
coastal lagoons.
"We can mitigate the impacts of these activities by restoring environmental
flows. Allocating water for the environment can maintain lagoon flushing, and
nutrient runoff can be reduced by upgrading wastewater plants, reestablishing
wetlands, and increasing efforts to retain nutrients in our agricultural lands
throughout catchments worldwide.
"To buffer the effects of drought or sea‑level rise, we could also reopen
closed tidal inlets to improve mixing, or improve salt-tolerant vegetation
coverage to trap sediment and slow evaporation."'
Via Susan ****
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
