JoNova

A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).


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Life adapts — fish evolved from salt to fresh water in just fifty years

In 1964 an earthquake made some parts of the Pacific into ponds on a few islands. Fifty years later and the fish in those ponds are now freshwater fish. Apparently the genes for dealing with that sort of wild extreme change are held by some of the fish in the crowd and natural selection can work its wonders in a decade.

In terms of ocean acidification, this is as catastrophic as it gets, not only did the ocean become “more acidic” but it stopped being an ocean.

I can’t get much worse than this for a fish, and yet somehow life on Earth had the answer.

What’s the pH of those ponds — The ocean pH is 8.1, rain is 5.5. Those ponds will be somewhere in between.

And some people think a man-made “ocean acidication” that’s smaller than this and slower, will devastate the ocean.

 

Science Daily

Evolution is usually thought of as occurring over long time periods, but it also can happen quickly. Consider a tiny fish whose transformation after the 1964 Alaskan earthquake was uncovered by University of Oregon scientists and their University of Alaska collaborators.

The fish, [...]

Global Warming to destroy sea-food as well

It’s a disaster for fish and chip shops. Children won’t know what a sea-food restaurant is.

Our oceans are warming by 0.005 °C per year (if you believe a thermometer system with a 0.5 °C error). But fish that cope with five degrees of natural variation will apparently be devastated by an average rise of five thousands of a degree per year. Who knew?

Earth’s oceans vary from 0 – 30° C. Warm and cold currents wander, eddy currents swirl. Very little of the ocean’s surface is actually at the exact “average” temperature. In any one spot, temperatures can be a full five degrees above or below average (as in this NOAA graph, below).

The sea surface temperature varies by up to five degrees from average every day

Humans may well be changing global fish stocks, but why toss in the unscientific advertising for “climate change”? As for the acidification scare, ocean pH changes on a daily basis, and hundreds of studies show that marine life might even benefit from a slight increase in “acidification”.

ScienceDaily

Seafood supply altered by climate change

The global supply of seafood is set to change substantially and many people will not [...]

Salmon quite happy to adapt to warmer world

You will never guess, but salmon that survived the hot Holocene period, and the even hotter Eemian, will probably be OK in a slightly warmer world. Expert researchers found this surprising.

Given the broad spread of Salmon in the Northern Hemisphere, and their past survival through every single interglacial warm period of the Pleistocene, I would have thought that they could cope with quite a bit of  climate change. As it turns out, they cope so well, that even salmon eggs that come from a 12C environment can be raised in an environment a whopping 8C warmer, and they were not noticeably any worse off.

Part of the concern with salmon was the spawning and eggs, and the problem with getting the salmon to shift their maternity wards and childcare arrangements (which they seem very attached too). But presumably those breeding grounds have varied before in temperature, and salmon didn’t die out, so — at least with this problem — nature has it figured out.

Map: Salmon and Climate Change, Fish in hot water, Red List.

Atlantic salmon also show capacity to adapt to warmer waters

Populations of Atlantic salmon have a surprisingly good capacity to adjust [...]

Climate change could stop fish finding their friends

Filed under: Light relief (for a moment til we get back to The solar model)

Not only will your air conditioner make little fish more reckless, but other fish might seriously not be able to find their friends for coffee. I did not make up that headline. Your taxes did.

Note the carefully phrased results:

“Whilst fish kept under normal conditions consistently chose the familiar school, fish reared under high CO2 conditions showed no preference for either the unfamiliar or familiar school.”

If increasing CO2 was a politically-correct achievement, would that same result carry a headline telling us that “Climate Change makes Fish More Confident with Strangers”?

[...]

Look out! Climate change makes fish reckless

AIMS researchers found that fish near a natural CO2 vent were not as scared of predators as their colleagues from more alkaline water: “Ocean Acidification robs reef fish of their fear of predators”.

They compared populations in reefs with normal pH levels with those near the vent. I note this line in the abstract didn’t make it to the press release:

“Contrary to expectations, fish diversity and community structure differed little between CO2 seeps and nearby control reefs.”

So the natural laboratory of the vent has biodiversity and a community, despite the “acid” (which is not acidic of course). Milne Bay, I gather, has pH of 7.7.

The abstract points out that there might be a reason why fish are bolder:

“Our results suggest that recruitment of juvenile fish from outside the seeps, along with fewer predators within the seeps, is currently sufficient to offset any negative effects of high CO2 within the seeps.”

Less predators, anyone?

So these might be well adapted little fish that suit the natural environment around them? Call the press…

If warming were politically correct, then people might say the fish became more confident. : -)

Indeed shouldn’t we worry that fish in higher [...]

Zebra Fish like it warm – they swim faster and adapt even better to climate change

Experiments with Zebra Fish show that if their embryo’s develop in warmer water, they not only are able to swim faster but they cope better in both warmer and colder water. (How catastrophic can that be, I ask you?)

ScienceDaily (Aug. 14, 2012) — New research by McMaster University biologist Graham Scott suggests that growing up at warmer temperatures helps some aquatic animals cope with climate change, raising questions about the limits of adaptation.

Scott and Johnston found that when embryos raised in warm water experienced temperature variation as adults, they could swim faster, their muscle was better suited for aerobic exercise, and they expressed at higher levels many of the genes that contribute to exercise performance.

The improvements were true for the adult fish in warmer and colder water alike — a finding that surprised the researchers.

“We thought that they might do better under warmer conditions because they grew up in warmer conditions. We didn’t think they’d also do better under colder conditions, but they did.

Their research shows the fish are hardier after being raised in a warm-water nursery, and raises the question of how far the temperature [...]