Increasing ocean temperatures are having a profound effect on a particular species of sea creature.
Populations of Antarctic Krill, a tiny species of crustacean, are moving closer to the Antarctic circle, as a result of warming seas.
Data about the population distribution of the krill has been collected over the past 90 years. The data was published in the journal Nature Climate Change this week.
It shows a clear shift in distribution in recent years. The krill are moving south towards the Antarctic circle where the sea temperature is lower. Not only has the distribution changed, but the total quantity of krill decreased too.
“Our results suggest that over the past 40 years, the amount of krill has, on average, gone down, and also the location of the krill has contracted to much less of the habitat. That suggests all these other animals that eat krill will face much more intense competition with each other for this important food resource,” Simeon Hill from the British Antarctic Survey told BBC News.
Krill are a staple food source of animals such as whales, seals and penguins. If this trend continues, it is likely that populations of these animals will begin to decline too.
New development in Alzheimer’s research
A protein has been identified which accurately predicts the onset and progression of Alzheimer’s disease.
The research was published in Nature Medicine. Mathias Jucker, who headed up the study, reports that the protein, called ‘Neurofilament [light chain]’, can be detected up to 16 years before the onset of symptoms.
Alzheimer’s is a brain disorder that causes memory problems which worsen over time. At present, there are no effective treatments for the disease. This is because once symptoms appear, the extent of cell death in the brain is too great to be repaired.
When cells die, their contents are released, and can be found in the blood. Normally such molecules quickly breakdown, however the protein in question, Neurofilament, is resistant to breakdown. The study showed that Neurofilament builds up in the blood before any symptoms occur, and can be detected many years before the first signs of the disease appear. Neurofilament can accurately predict the course of the disease when monitored over time.
“It is not the absolute neurofilament concentration, but its temporal evolution, which is meaningful and allows predictions about the future progression of the disease,” says Jucker.
This is an important discovery, as it can be used to test the effect of new drugs on disease progression.
Cerebellum gets social
A brain area originally thought to be responsible for movement alone, has another important function. The cerebellum, an area at the back of the brain, has been found to play a role in social interaction.
New research suggests that the cerebellum is linked to another brain area called the Ventral Tegmental Area (VTA), which is known to be involved in reward and reinforcement.
The experiment, published in Science journal, was carried out using mice. Electrodes in the brains of the mice were used to record activity from brain cells in the cerebellum which were linked to brain cells in the VTA.
Researchers noticed that these particular cells were active when the mice were interacting with other mice. When the cells were artificially turned off using lasers, the mice no longer preferred to spend time with other mice rather than spend time alone. This strongly suggests the cells play a role in social behaviours.
Brain disorders such as Autism have been associated with damage to the cerebellum. Social deficits observed in individuals with autism might be explained through this link between the cerebellum, VTA and social behaviours.