Large areas of open ocean starved of oxygen

 

Vancouver

Large regions of the open ocean are being starved of oxygen because of warmer sea temperatures according to studies showing that fish and other marine creatures are moving into narrower habitats to avoid suffocation.

Marine researchers said they have discovered growing areas of the ocean that suffer from hypoxia - oxygen depletion - which they believe is the result of warmer sea temperature caused by global warming.

Warmer sea temperatures increase stratification, where warm, stagnant bodies of surface water sit on top of cooler water and prevent the normal mixing that results from the vertical circulation currents of the ocean, said Professor Lisa Levin of the Scripps Institution of Oceanography in La Jolla, California.

Warmer water also holds less dissolved oxygen than cold water. This means that the stable regions of the deep ocean are also beginning to experience temperature rises that affect concentrations of dissolved oxygen, Professor Levin said.

“The water is getting warmer, and warm water holds substantially less oxygen than cold water - water at 2C holds 20 per cent more oxygen than 20C water....Off southern California over the past 22 years we’ve lost about 30 per cent of the oxygen at depths of around 200 to 300 metres,” Professor Levin said.

“It’s a big effect, but also the stratification of the ocean is reducing the amount of vertical mixing of the ocean which prevents surface layers which are rich in oxygen being carried to deeper layers of the ocean,” she said.

“We believe it is linked to atmospheric warming and ocean warming in as much as CO2 has come from fossil fuel burning, it is linked to humans,” she added.

At the same time, the oceans are becoming more acidic - with lower pH values - as they absorb more carbon dioxide from the atmosphere, she said.

“These low oxygen zones are also low pH [more acidic] zones because the same process that reduces oxygen, that is respiration, also produces carbon dioxide which reduces pH,” Professor Levin said.

“A key feature of these low oxygen, low pH zones is their narrow biodiversity and although these areas do occur naturally, they are expanding with low-oxygen areas moving up into shallow water,” she told the American Association for the Advancement of Science.

“The vertical distribution of deep-ocean species is shifted upwards. They have to move to avoid the low-oxygen waters. At the same time, the surface waters are getting warmer and more acidic and creating less suitable habitat from above,” she said.

“The appropriate habitat for many ocean animals is being compressed causing many animals to live in a smaller area at higher densities in waters that may be shallower than normal.

“This changes their interactions with other species, with predators and competitors and it also makes them much easier targets for fishermen,” Professor Levin told the meeting.

Deep-water temperature gauges off Spitsbergen in the Arctic and in the Southern Ocean near the Antarctic have recorded temperature increases of between 0.03C and 0.5C, and as much as 1C, which is highly significant for a a stable environment that does not change at all from one century to the next, she said.

“Those are significant numbers. The warming is more intense at the sea surface but it reaching the deep water,” Professor Levin said.

“Although we think of the deep sea as pristine, over the past 30 years since I’ve been studying the deep oceans they have become increasingly susceptible to human disturbance,” she said.

PROMOTED VIDEO
Arts and Entertainment
tv
News
Katie Hopkins appearing on 'This Morning' after she purposefully put on 4 stone.
peopleKatie Hopkins breaks down in tears over weight gain challenge
Life and Style
fashionModel of the moment shoots for first time with catwalk veteran
Life and Style
fashionAngelina Jolie's wedding dressed revealed
Sport
Alexis Sanchez, Radamel Falcao, Diego Costa and Mario Balotelli
footballRadamel Falcao and Diego Costa head record £835m influx
News
i100
News
ebooksAn unforgettable anthology of contemporary reportage
Arts and Entertainment
Madame Vastra and Jenny Flint kiss in Doctor Who episode 'Deep Breath'
tv
Arts and Entertainment
Olivia Colman topped the list of the 30 most influential females in broadcasting
tv
Life and Style
techIf those brochure kitchens look a little too perfect to be true, well, that’s probably because they are
Arts and Entertainment
Danish director Lars von Trier
tvEnglish-language series with 'huge' international cast set for 2016
Life and Style
tech
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Executive Assistant/Events Coordinator - Old Street, London

£35000 - £38000 per annum + benefits: Ashdown Group: Executive Assistant/Event...

Female PE Teacher

£23760 - £33600 per annum + pre 12 week AWR : Randstad Education Manchester Se...

Secondary supply teachers needed in Peterborough

£21000 - £35000 per annum: Randstad Education Cambridge: The JobAre you a trai...

Year 3 Teacher Cornwall

£23500 - £40000 per annum: Randstad Education Plymouth: Year 3 Primary Teacher...

Day In a Page

'I’ll tell you what I would not serve - lamb and potatoes': US ambassador hits out at stodgy British food served at diplomatic dinners

'I’ll tell you what I would not serve - lamb and potatoes'

US ambassador hits out at stodgy British food
Radio Times female powerlist: A 'revolution' in TV gender roles

A 'revolution' in TV gender roles

Inside the Radio Times female powerlist
Endgame: James Frey's literary treasure hunt

James Frey's literary treasure hunt

Riddling trilogy could net you $3m
Fitbit: Because the tingle feels so good

Fitbit: Because the tingle feels so good

What David Sedaris learnt about the world from his fitness tracker
Saudis risk new Muslim division with proposal to move Mohamed’s tomb

Saudis risk new Muslim division with proposal to move Mohamed’s tomb

Second-holiest site in Islam attracts millions of pilgrims each year
Alexander Fury: The designer names to look for at fashion week this season

The big names to look for this fashion week

This week, designers begin to show their spring 2015 collections in New York
Will Self: 'I like Orwell's writing as much as the next talented mediocrity'

'I like Orwell's writing as much as the next talented mediocrity'

Will Self takes aim at Orwell's rules for writing plain English
Meet Afghanistan's middle-class paint-ballers

Meet Afghanistan's middle-class paint-ballers

Toy guns proving a popular diversion in a country flooded with the real thing
Al Pacino wows Venice

Al Pacino wows Venice

Ham among the brilliance as actor premieres two films at festival
Neil Lawson Baker interview: ‘I’ve gained so much from art. It’s only right to give something back’.

Neil Lawson Baker interview

‘I’ve gained so much from art. It’s only right to give something back’.
The other Mugabe who is lining up for the Zimbabwean presidency

The other Mugabe who is lining up for the Zimbabwean presidency

Wife of President Robert Mugabe appears to have her sights set on succeeding her husband
The model of a gadget launch: Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed

The model for a gadget launch

Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed
Alice Roberts: She's done pretty well, for a boffin without a beard

She's done pretty well, for a boffin without a beard

Alice Roberts talks about her new book on evolution - and why her early TV work drew flak from (mostly male) colleagues
Get well soon, Joan Rivers - an inspiration, whether she likes it or not

Get well soon, Joan Rivers

She is awful. But she's also wonderful, not in spite of but because of the fact she's forever saying appalling things, argues Ellen E Jones
Doctor Who Into the Dalek review: A classic sci-fi adventure with all the spectacle of a blockbuster

A fresh take on an old foe

Doctor Who Into the Dalek more than compensated for last week's nonsensical offering