The rising of heatwaves has caused a concern for the marine ecosystem (Photo for representation: AI generated)
What is a heatwave?
A heatwave is a long period of hot weather.
Heatwaves can occur with or without humidity.
It has the capability to engulf a large area.
What is a marine heatwave?
A marine heatwave is a period of unusually high ocean temperature.
It is defined through its duration and intensity.
It occurs when the surface temperature rises remarkably over the average.
Scientists measure the Earth’s surface through the temperature of the ocean’s surface.
The marine heatwaves
A few decades back, marine heatwaves were a very rare phenomenon. But in recent decades, the ocean has warmed up quite a bit and heatwaves have been very common.
In January 2000 4.2% of ocean surface was experiencing heatwaves.
In January 2004, the percentage increased by 0.1%, 4.3% of the ocean’s surface was experiencing heatwaves.
Ten years later, in January 2014, the number had increased to 8.4%.
In January 2024, 40.9%, almost 41%, share of the ocean’s surface faced heatwaves.
Unusual marine heatwaves have occurred all over the planet in recent years. Scientists have even coined a new term ‘super marine heat waves’ because of how severe some of these events have been.
The coasts of the United Kingdom and Ireland experienced unexpectedly fierce heatwaves. It started in April, and the rise in temperature was much earlier than usual. Australia got hit by heatwaves in two coasts.
The Marine Ecosystem
The change in temperature has also caused trouble for marine life, and caused changes in sea surface levels and weather dynamics.
Marine Life
Coral reefs are underwater ecosystems formed over time.
They can bleach and die if the water temperature increases too much. According to a recent report, 84% of coral reefs experienced a bleaching level of heat from January 2023 and March 2025.
Change in sea surface levels
Last year in 2024, sea levels rose faster than expected.
It came from sea water as it expanded due to heat, unlike the melting of glaciers which were bigger reasons a few years before.
Change in weather dynamics
Marine heatwaves can also lead to intense and more destructive hurricanes.
Last year, the Philippines faced numerous cyclones due to the same reason.
The troubles faced
The northern shrimps are species of cold-water shrimp found in the northern Atlantic and northern Pacific Oceans. Their estimated population in 2010 was 27.25 billion. But two years later in 2012, the population decreased to 8.2 billion. By 2023, the population went down to 200 million.
There are some regions around the world where monitoring of marine life isn’t as good as other places, hence scientists and researchers find it hard to know exactly what is happening.
The heat wave known as “The Blob” reduced waves which meant fewer nutrients on the sea surface. Less nutrients would mean less phytoplankton (microscopic marine algae), which would mean less zooplankton (animal-like microscopic organisms) which feed on phytoplankton, and that would lead to fewer fish.
There was a drop in whale sightings in 2021.
