Warming Seas Cut Dissolved Oxygen Content, 6 Decades Of CA Records Show - 20% O Loss = 60% Fish Loss

[hatrack]

Seafood could be going off a lot of menus as the world warms. More than half of a group of fish crucial for the marine food web might die if, as predicted, global warming reduces the amount of oxygen dissolved in some critical areas of the ocean – including some of our richest fisheries.

The prediction is based on a unique set of records that goes back to 1951. California has regularly surveyed its marine plankton and baby fish to support the sardine fishery. "There is almost no other dataset going back so far that includes every kind of fish," says Tony Koslow of the Scripps Institution of Oceanography in La Jolla, California, who heads the survey. The survey records also include information on water temperature, salinity and the dissolved oxygen content.

Koslow's team studied records of 86 fish species found consistently in the samples and discovered that the abundance of 27 of them correlated strongly with the amount of oxygen 200 to 400 metres down: a 20 per cent drop in oxygen meant a 63 per cent drop in the fish. There have been several episodes of low oxygen during the period in question, mainly in the 1950s and since 1984.

Global climate models predict that 20 to 40 per cent of the oxygen at these depths will disappear over the next century due to warming, says Koslow – mainly because these waters get oxygen by mixing with surface waters. Warmer, lighter surface waters are less likely to mix with the colder, denser waters beneath. Of the 27 species most affected by low oxygen, says Koslow, 24 were "mesopelagic": fish that spend the daytime in deep, dark waters below 200 metres to avoid predators such as squid that hunt by sight. There are 10 billion tonnes of mesopelagic fish globally – 10 times the annual global commercial catch – and they are a vital food for other fish and marine birds and mammals.

EDIT

http://www.newscientist.com/article/dn20882-warming-seas-could-smother-seafood.html

[jpbollma]

1. The environment is THE issue

jobs pales in comparison. We have only ONE planet, after we ruin that we will all be unemployed (and dead).

[villager]

2. "There are no jobs on a dead planet"

We used to say that back in the 80's. You can tell how well people listened.

[Vincardog]

3. Welcome to DU. We can not kill the planet. We can however make it uninhabitable for US. Give it a

few million years without the human infection and the earth will be fine.