Amazing stuff!
More examples how little we still know about our oceans, but many charlatans (incl. scientists) claim anthropogenic global warming!
It seems marine heatwaves were unknown until the 1980s (see e.g. Wikipedia).
According to Google: "The earliest widespread marine heatwave events identifiable in compiled global records date back to the 1920s, with major studies creating datasets that track these events from around 1925 onwards, revealing significant increases in frequency and duration over the 20th century, though specific large events like "The Blob" (2014-2016) are more famous." Google did not say when these data was compiled, I suspect after 1980.
"... A team of researchers has discovered that a single, large-scale heat wave has affected ecosystems and trophic interactions in the subpolar North Atlantic, and the effects are still felt today. ..."
"... From unicellular algae to whales – all organisms were affected by the unexpected heat. Capelin, a cold-water fish species started to suffer, while warmer water loving species, such as cod and haddock expanded their distribution northwards. Capelin is the most important subpolar forage fish species in the North Atlantic and moved its spawning areas northwards from south-western Iceland. This had far-reaching consequences: Eggs and larvae started drifting to unfavorable habitats close to the coast off East Greenland, where they have a lower probability of survival because they are not adapted to the local conditions. Species, such as humpback whales, benefit from these changes, follows capelin and is much more regularly seen in South-East Greenland than it historically used to be. ..."
From the abstract:
"Marine heat waves (MHWs) are increasing in frequency and intensity, but wider effects are unexamined in the North Atlantic, and there are uncertainties regarding the spatial scale, magnitude, and persistence of MHWs’ impacts on ecosystems.
We show that a sudden and strong increase in the frequency of MHWs in and after 2003 was linked to widespread and abrupt ecological changes. This upheaval spanned multiple trophic levels, from unicellular protists to whales.
Every examined region showed a reorganization from species adapted to colder, ice-prone environments to those favoring warmer waters and the event’s impacts altered socioecological dynamics.
This review provides evidence for large-scale connectivity across ocean basins. However, it reveals that the magnitude of ecological impacts seems to vary among events highlighting key knowledge gaps for predicting ecosystem responses to MHWs.
Understanding the importance of the subpolar gyre and air-sea heat exchange will be crucial for forecasting MHWs and their cascading effects."
How a heat wave in 2003 has changed the North Atlantic until today (original news release) "Extreme events change the ecology of oceans abruptly: For example, a marine heat wave in 2003 had such strong effects on species composition and trophic interactions of the subpolar North Atlantic that these impacts last until today. Researchers led by the Thünen Institute of Sea Fisheries in Bremerhaven just described this. The study has recently been published in Science Advances."
Major heat wave in the North Atlantic had widespread and lasting impacts on marine life (open access)
Fig. 1. Major currents in the North Atlantic. Case study areas highlighted in green.
Fig. 3. Major heat wave in the North Atlantic had widespread and lasting impacts on marine life. [How many MHWs were missed? What about MHWs in other oceans?]
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