[Animals] How do fish live in almost oxygen-free depths?

[SnO]

 

Mohammad ALHADDAD
Although oxygen is an essential element for human and animal life, marine biologists say otherwise. Researchers recently revealed the existence of large fish populations living in the depths of the Gulf of California, where there is almost no oxygen.

 

 

The researchers used robotic devices to access the area where these fish exist and monitor life in it, and noticed that species of sharks, grenadiers fish, and cusk eel grow and thrive in conditions of low oxygen, which would be fatal to most other fish.

This discovery could help scientists understand how other marine animals deal with constant changes in ocean chemistry, according to the results of the study, published in the journal Ecology, by researchers from the Scripps Institution of Marine Sciences at the University of California, Santiago, USA.

Field studies
The research was led by biologist James Barry of the University of California, and the field studies were conducted in 2015, when the research team - consisting of nine researchers - carried out a series of dives into several deep ocean basins in the Gulf of California using a remotely operated vehicle belonging to the Gulf Aquarium Research Institute. monterey.

The deep waters of the Gulf of California contain some of the most oxygen-poor marine habitats in the world.

Sensor readings on board indicated that oxygen concentrations in this environment were 1-10 to 1-40 lower than environments tolerated by other fish that can adapt to lower oxygen levels.

The authors of the study hypothesized that the enlarged gills enabled the fish that take the bottom of the Gulf of California as their habitat to increase the absorption of oxygen, in addition to the smoothness and smoothness of the bodies of these species.

 

 

Little oxygen lover
The study warned that the continuation of the current rates of ocean temperature rise may lead many marine species to extinction, or at best adopt habitats characterized by harsh conditions such as very deep areas with little oxygen.

And because what the research team found is unprecedented, they proposed naming this species that lives with a minimum amount of oxygen, as ligooxyphile, which means in the Greek language "little oxygen lover".

The study was based on observations of 60 hours of video footage that enabled the research team to correlate observations of these fish species (sharks, pitcher fish, and clover eel) with the oxygen conditions in the study area.

Types of sharks, grenade throwers and clover eels grow and flourish in low oxygen conditions (the island)
Types of sharks, grenade throwers and clover eels grow and flourish in low oxygen conditions (the island)
Amazing results
The lead researcher in the study, Natalia Gallo, explained in a statement to Al-Jazeera Net that the study adopted the latest technologies to explore and study the deep seas, and included a comparison of deep-sea communities in the northern, central and southern Gulf of California as a way to understand environmental variables such as oxygen and temperature that change with climate change and affect deep-sea communities. seas.

And Gallo indicated that the importance of this discovery is that it challenges current assumptions, and suggests that fish have a much greater possibility of adapting to anoxia, and the researchers' observations indicate that these fish show a higher tolerance for hypoxia than most large invertebrates in the region.

The researcher indicated that the team that completed the study is not yet sure of the ecological role played by these fish, or what adaptation factors allow them to survive under these conditions, and stressed the need to do more work to study these species.

 

https://www.aljazeera.net/news/science/2019/1/24/أسمالك-محيط-أكسجين