Our Oceans Are Significantly Losing Oxygen, Threatening Marine Life and Fisheries

The IUCN ran the largest report of its kind on the topic, releasing the worrying information.
Fabienne Lang

Marine life and many fish species are in grave danger as our oceans are losing oxygen due to climate change and nutrient pollution.

The IUCN carried out the biggest report of its kind on the matter, shedding worrying light on the subject.

It's no new topic, as nutrient pollution has been occurring for many years, however, climate change is making the lack of oxygen much worse as time goes by.


What happens when oceans lose oxygen?

The numbers are worrying. Approximately 700 ocean sites have low oxygen at the moment, a stark comparison to 'just' 45 in the 1960s.

This lowering of oxygen is threatening many marine species such as tuna, marlin, and sharks according to researchers.

The primary factor for this lack of oxygen is still nutrient run-off of chemicals from farms and industries, however, climate change is now playing a big part as well. 

Our oceans absorb much of the heat in our atmosphere, and as this has been increasing due to higher levels of carbon dioxide because of the greenhouse effect, our oceans are suffering.

Warmer waters can hold less oxygen. 

In turn, waters with warmer temperatures house more species such as jellyfish, but aren't as good for bigger fish species such as tuna. For these species, including marlin and sharks, this is very bad news.

"We have known about de-oxygenation but we haven't known the linkages to climate change and this is really worrying," said Minna Epps from IUCN.

"Not only has the decline of oxygen quadrupled in the past 50 years but even in the best-case emissions scenario, oxygen is still going to decline in the oceans."

Tropical regions in the world will suffer the most according to researchers.

If we carry on as we are currently, by 2100 our oceans will lose between three to four percent of their oxygen. This may not sound like a lot, but even small changes can have a massive impact on marine life.

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Epps warned that "If we run out of oxygen it will mean habitat loss and biodiversity loss and a slippery slope down to slime and more jellyfish."

"It will also change the energy and the biochemical cycling in the oceans and we don't know what these biological and chemical shifts in the oceans can actually do."

Not a promising future for our oceans if changes don't happen right now.

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