Amazing new research has shown that we can detect what species of fish are found in different parts of our seas simply by collecting samples of the local seawater. The key to identifying which species are present is in traces of DNA - known as environmental DNA (eDNA) - which are left in the surrounding water by fish that pass through. Just half a litre of seawater from a temperate marine ecosystem in Denmark provided DNA fragments from 15 different fish species, including some that were rarely recorded by more invasive conventional methods, as well as 4 bird species. Experiments show that even small fragments of eDNA degrade to the point that they are no longer detectable within days, suggesting that the method gives an up-to-date and accurate recording of the species that inhabit the area at that point in time. A further study looking into the possibility of marine mammal detection using the eDNA method suggests that greater volumes of seawater are needed to be analysed in order to detect them, but that eDNA has the potential to support current visual and acoustic methods of species detection for marine mammals as well as fish.
Ref: Thomsen P. F. et al., 2012. Detection of a diverse marine fish fauna using environmental DNA from seawater samples. PLOS One [link]
Foote A. D. et al., 2012. Investigating the potential use of environmental DNA (eDNA) for genetic monitoring of marine mammals. PLOS One [link]
Incredible new findings show that the organs of the Burmese python (Python molurus bivittatus), including the heart, grow up to twice their normal size each time a snake consumes a meal - the bigger the prey, the bigger the organs become in order to digest it. By just 12 hours after the kill is made, the organs have begun to grow, and they peak at their maximum size at around 76 hours, before returning to normal at around ten days. Whilst the organs are enlarged, metabolic rate is boosted to an astounding 40 times greater than normal - the equivalent of the increase seen in a racehorse when galloping compared to at rest - except in the Burmese python, this lasts for days on end, rather than just minutes. Studying the physiological basis of this amazing rapid addition and removal of tissue to the body’s organs could prove clinically useful, including in learning to treat atrophy-based heart disease in cancer patients and astronauts as well as in reducing size in disease-enlarged hearts.
Ref: Rizzo J., 2012. Gross Anatomy. National Geographic Magazine August 2012
Set against the consuming blackness of space, the earth is a beguiling blue-green ball. Barely two dozen people have ever experienced the emotion of seeing our planet from the moon and beyond, yet the fragile beauty of the pictures they sent back home is engraved in the minds of a generation. Nothing compares. Petty human squabbles over borders and oil and creed vanish in the knowledge that this living marble surrounded by infinite emptiness is our shared home, and more, a home we share with, and owe to, the most wonderful inventions of life.