Image Credit: Glasgow Digital Library, University of Strathclyde
It's not like there's a shortage of evidence supporting the scientific consensus that greenhouse gases are warming the planet, but further support for climate change keeps rolling in anyways. And sometimes, it comes from rather unexpected places -- like from samples collected from a 1901 Antarctic expedition, for example. The turn-of-the-century explorer took marine samples from his expeditions to Antarctica, and after analyzing them, scientists have found that they provide further evidence of man-caused climate change. Famous explorers like Shackleton and Captain Robert Falcon Scott brought back ample marine samples from their expeditions to Antarctica from 1901-1904. One of the smallest animals they preserved, a twig-like bryozoan, is turning out to be a valuable indicator of the levels of carbon dioxide in oceans.
Image: British Arctic Survey
Here's BBC Science:
The expeditions in the early 1900s brought back many finds including samples of life from the sea floor. Comparing these samples with modern ones, scientists have now shown that the growth of a bryozoan, a tiny animal, has increased in recent years. They say this means more carbon dioxide is being locked away on the ocean bed.The growth rates have been published in a study in the journal Current Biology, by researchers from the British Antarctic Survey.
The tiny bryozoan, Cellarinella nutti, looks like a branching twig that has been stuck into the sea floor. It grows during the period in the year when it can feed, drawing plankton from the water with its tentacles. The length of the feeding season is reflected in the size of the annual growth band - just as with tree rings.
The findings make complete sense -- there's really no doubt that the oceans are becoming increasingly saturated with carbon dioxide. The oceans are absorbing more and more CO2 from the atmosphere as we humans pump more and more into it -- which is why pH levels are decreasing and the oceans at large are acidifying. And these little twiggy creatures collected at the turn of the last century are yet another indicator that this process is indeed occurring.