Sunday, March 8, 2015

Expanding into hostile environments by using less oxygen

we're just coming over to say hi!
photo: Monterrey Bay Aquatic Research Inst.
Last week's post on the Humboldt, or jumbo, squid, taught me (and perhaps you too?) how these red devils of the deep change color and flash each other to communicate. Plus they beat up the people that try to film them doing it.

There's more to this crabby monster than just producing pretty color and light.

Humboldt squid have another mysterious ability that may be enabling them to succeed in more and more places: they thrive in low oxygen environments that most other big critters tend to avoid.

Some background: these beasts already contribute to the ocean environments, both as a predator on crustaceans and as prey for even bigger critters – sperm whales, bill-fishes, tunas, sharks – and people.

In fact, they are key sources of income for whole communities: jumbo squid is now the third largest fishery in Mexico.

big catch
photo: FishGuy, Wikipedia
What's curious and impressive is that Humboldt squid can survive for hours in waters hundreds of meters deep that have very little oxygen, about 10% of the oxygen concentration at the surface.

Sharks, tunas, and whales all dive to these depths, but can't stay long because they need to either breathe (whales) or take in more O2 from the water. Meanwhile, the jumbo squid can not only stay down there for long periods but swim fast enough to hunt for food and avoid becoming food themselves.

Scientists don't yet know why or how the squid can survive so well in the low-oxygen depths, but they've found that squid can shut down non-essential body processes, such as protein synthesis, in those conditions, which helps them conserve energy and continue to function.

Brad Seibel, a comparative animal physiologist at the University of Rhode Island, explained:“When oxygen drops too low, these squids are able to suppress metabolism, that is, shut down expensive cellular processes."

where jumbo squids thrive!
Plus, jumbo squid can extract oxygen even from hypoxic (low oxygen) waters, giving them a competitive advantage over other active predators.

Jumbo squid live only about 2 years, so they really have to chow down and make the most of their time in order to grow and remain active.

Nevertheless, this ability may enable the species to expand its geographic range, moving from the waters off South and Central America into into the colder zones of California and farther north.

It may be spending more time and outcompeting other predators in waters in low oxygen zones, which may be expanding with climate change, said Seibel.

squids and studs share some basic principles
image: TattooPinners
It's as if the squid are successfully following the low-oxygen zones – and they are starting to eat fish that people care about.

So maybe you can match the strategy of the Humboldt squid -- eat well, grow fast, and die young.

And function just fine with almost no oxygen by shutting parts of yourself down when needed.

What process would you shut down if you could?

something completely different -- squid friends?
image: AlgosAndBlues

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