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
These days it is extraordinary to discover even a single species of bird that is new to science, but a recent study has identified not just one, but two new species of owls endemic to the Philippines. The Cebu hawk-owl (Ninox rumseyi) (top) and Camiguin hawk-owl (Ninox leventisi) (bottom) first sparked ideas that they were not simply subspecies of other Ninox hawk-owls found across Asia and Australasia, as was once thought, when researchers heard their highly distinctive calls (both of which can be heard free on AVoCet). Owls do not learn their songs from relatives or other members of their species, but instead they are encoded in their DNA - so researchers were lead to believe that these unique songs must reflect significant genetic differences between the birds in question, suggesting they were separate species. Many years of supporting study have finally culminated in the formal identification of these birds as species new to science. The Camiguin hawk-owl, interestingly, is the first and only owl species known to have blue-grey eyes.
Ref: Cameron L., 2012. Two new owls discovered in the Philippines. Michigan State University News [link]