The ocean’s falling oxygen levels are putting fish species at risk: report
Well the world’s deep oceans are in deep
trouble. This according to a new report presented at the UN climate conference
in Madrid today. The International Union for the Conservation of Nature says
there are many reasons for that but a big one is the steady fall in oxygen
levels. Now fish need oxygen just as much as land animals but the number of
so-called dead zones, which are places with little or no oxygen, is growing
quickly. When research began in the 1960s scientists counted 45 dead zones but
today there are more than 700. The lower oxygen levels are especially hard on
larger species like sharks. Minna Epps is the director of the Global
Marine and Polar Program with the International Union for the Conservation
of Nature and she joins us right now from Madrid. Minna thank you for joining
us today. Thank you for having me. Listen I want to begin first and foremost with
impact. What does a lower oxygen level in oceans actually translate to? Well the
concrete things that it translates to on a general scale would be the loss of
biodiversity, loss of biomass. Loss of habitats as these are shrinking or it
could be also alternate of alteration of the energy and the biochemical cycling.
So what is causing this lower oxygen level that’s now being tracked around
the world? Well the primary cause of deoxygenation
which has occurred far most in the coastal areas what’s been 30 to 40
kilometers offshore like you would have seen and then lower the Gulf of St.
Lawrence. That is caused mainly by nutrient pollution so that’s a primary
course in general what we’re seeing now is also the linkages to climate change
as increased CO2 levels emissions has resulted in ocean warming. So warmer
water contains less diesel – less oxygen – which means that the oceans due to
climate change are becoming warmer more sour and ultimately breathless.
Breathless but I do wonder what is the impact on that on humans?
Well it’s it’s all connected so from the oceans you know we get food, it’s
it’s a carbon storage, it generates oxygen, it’s part regulates,
heat, excess heat so it’s part of a regulatory system and we all need oxygen
as well to breathe. But what climate change does is weaken this ability, the
support system, of of the ocean and you mentioned in the 700 sites, I mean the
this two per cent decline in oxygen levels is an average within that you have massive
huge regional variations. So this could be some areas up to 30 per cent etc but we’re
also seeing that the future projections is another three to four percent both
under high and a lower emission targets. So it makes it harder to actually regulate
oxygen and global temperatures you’re saying and talk about the economic
impact of this because I think for many people this is part of the picture as
they try to understand the impacts of climate change. Yeah so I think that now
they’re talking about or looking at the ocean saying, well if the ocean was a
state it would be in in terms of GDP it would be the seven largest. So because
we’re looking at all the benefits that we are getting for the ocean and its
services and the potential that’s there so we really need to think about this
and a concrete thing would be commercial fishing which is important for the socio-economics. So look at the tuna fisheries for example they need a lot of oxygen-rich waters and so we’re seeing migration to more nutrient and ocean
and rich waters but so it’s it could be habitat loss but it can also affect us
in the way that’s important commercial species which is like code for example.
It can actually hamper their growth as well because they don’t have oxygen
enough oxygen they have enough to sustain but they might not grow or
reproduce as much as they would under more optimal conditions.
Well of course cod is a species of fish that Canada is very familiar with. This
deoxygenation as you say happening all around the world,
can you pinpoint the kind of effect this will have on Canada in particular? Well I
mean this report that’s been put together it’s from 67 scientists around
the world and there’s different geographical studies. So it’s 600 pages
of these different sites. There are studies looking at the Gulf of St.
Lawrence and looking at cod but also in some areas where they have actually
found deoxygenation has half since the 1930s in those areas.
So it’s an area I think 1,300 square kilometers of deoxygenation so so that’s
something that’s very close to home for you and as you mentioned before the cod
fishery. So can this be stopped are there things on a practical level
the people can do to stop this from happening? I mean there is a solution. I
mean the primary cost which is nutrient pollution of course there’s action that
that can be taken there but we need to ultimately cut emissions or have much
more ambitious targets towards cutting emissions. We need to invest in nature
based solutions so that’s in protecting and restoring ecosystems both from
mitigation and for adaptation but we also need to reduce other non climate
change stressors such as overfishing. We need to have sustainable fisheries that
can sustain and be more resilient to these changes that are occurring and so
that’s really here I think the decisions being made at the COP here in Madrid
will actually determine the future of our oceans whether there will be
thriving and marine biodiversity and oxygen-rich environment or whether they
will be damaged and irreversibly lost so I think that has an impact and then as
we said on a personal level we you know we can engage we can put public pressure
and we can make sure that we source sustain from sustainable sources.