Access
This article is part of Nature's premium content.
Published online 1 May 2008 | Nature | doi:10.1038/news.2008.795
News
'Ocean deserts' are growing
Low-oxygen regions have expanded over the past half-century.
Low-oxygen 'underwater deserts' in the tropical oceans have expanded over the past 50 years, according to new measurements. The most likely cause of the change is global warming, and climate models predict that the trend will continue, potentially threatening marine ecosystems.
To read this story in full you will need to login or make a payment (see right).
Comments
Reader comments are usually moderated after posting. If you find something offensive or inappropriate, you can speed this process by clicking 'Report this comment' (or, if that doesn't work for you, email redesign@nature.com). For more controversial topics, we reserve the right to moderate before comments are published.
It has been shown that, as CO2 levels in the atmosphere increase, oxygen levels are decreasing. Expecting the oceans to act as a carbon sink may have the same outcome. This article doesn't mention the effect of increasing CO2 levels in the ocean in relation to oxygen depletion but I think that it would make an interesting if not necessary addition to this research based on current conditions.
Although fisheries are uncommon under 300 m depth, the effect on fish populations can occur up to 2500 m. In fact, commercial fish depletion at shallower depths can be correlated with fish reduction from much lower ones. It should be payed attention to the vertical ecosystems range on any issue that concerns marine policies.
It is amazing to me that there are still people who do not believe in Global Warming! (i.e. Also amazing that some people do not believe the holocaust, moon landing, the world is round, etc... ad nauseam) How but some images and maps showing the areas. It would be great if some scientific body, agency, person could take images with the 'right' kinds of satellites to show these regions over time; and from one year to the next. (If the images already exist, why no links to them with the article? There has to be something!) We might not have images for as far back as we might like to go, but we should be cataloging these changes over time for future generations. Even correlating the images with Nasa images of the planet; Sun Spot activity; Magnetic Field variation; CO2 levels and of course Ice Core Samples, etc.... Than perhaps the many hypothesis that come from this and other similar news worthy events might be more significant. Perhaps even significant enough to make the correct changes and improve everyone's future. Just a thought!
maybe the water isnt heating up because of global warming at all. {Remember when} The tsunami hit? At that time some people beleived that Some sort of nuclear explosion or something real big caused that tsunami and it gave off radiation and killed alot of animalsm. It also made certain animals such as whales and dolphins come up from the depths and travel down rivers to get away from the unlivable water. I dont know this for a fact But I think I remember coast to coast am having an hour or so discussion about this. And I am not sure who the interview was with. That didnt sound like a global warming to me.
before rivers were restricted by dams the fresh water that flowed into the oceans added oxygen and lowered salinity of the coastal water,the colorado river for instance no longer reaches the gulf which i believe has caused the depleation of the marine life in that area as for global warming why doesnt anyone mention the fact that many of earths glaciers are growing? we only hear about the ones that are melting until we have the WHOLE TRUTH the problem will remain a political one...
I'm not certain what the tsunami has to do with the oceans heating up; very different geophysical events. It takes a lot of energy to change the temperature of a body of water (just think of how long it takes your kettle to boil), yet we can already measure the temperature changes in the ocean. All the nuclear arsenals on the planet could not do this, unless they generated a nuclear winter scenario, in which case, the waters would cool a bit. The damming of rivers, and the loss of their oxygen contributions is indeed a problem in coastal areas, but rivers are not large contributors to oxygen at depth, or to the overall oxygen concentration of the oceans. Most of the oxygen comes from mixing at the surface. Damming the Colorado River did indeed have profound effects on the biological community of the northern Gulf of California, but our work has shown that (1) the effect is relatively local because the Gulf is so well and rapidly mixed by tidal fluxes, and (2) while the effect was negative for some animals, and their numbers have declined drastically, the increasing salinity has lead to the increase of other animals more used to normal marine conditions. I'm definitely not advocating damming or excusing the abuse of the Colorado, but things are not always as straightforward as they first seem to be.
It is fairly well established that global warming leads to increase in sea-surface temperatures which will in turn impact on ocean vertical water circulation and oxygen distribution in the waters at dephths,actually causing a fall in oxygen levels. Presence of incresed levels of carbon dioxide in the waters may accelerate this process of anoxic conditions at ocean depths due to presence and migration of organisms to those regions which thrive in acidic and anoxic conditions. This aspect needs to be studied further ,since this can have its effects in reducing or altering the fish population distribution in shallow coastal waters of the oceans in due course.This coupled with nitrogen from fertilisers can spell disaster for coastal zone fishing community. SURESHKUMAR,SCIENTIST AND HEAD,PME,NIIST,TRIVANDRUM
Rubbish with a sensationalizing, asinine title ! Pray tell what kind of serious research was going into this 50 years ago ?? Just like many other aspects in the planets life, it is cyclical. Folks, the universe wobbles ;-)