New research has shown a surprising connection between sun spot activity and whale strandings, which suggests magnetic navigation could be far more important to whales than previously thought.
It is hard to imagine that the changing surface of the sun, over 93 million miles away, could have any impact on whales swimming around in our oceans. However a new paper produced by marine biologists, with help from an astronomer, suggests it may actually be directly altering the animals behaviour in a big way. The team, from Duke University and the Adler Planetarium, have highlighted a strong correlation between sunspot activity and cetacean strandings that suggests magnetic navigation may be far more important to whales than previously believed. But just how are the two things related? And how much can we really make of the connection?
If you have ever seen a close up image of the sun taken from space, you are likely to have noticed the odd black spots on its fiery surface. Those dark patches are what are known as sun spots and when they appear on the star’s surface it is the result of increased solar activity. This increase in activity, commonly referred to as solar storms, results in the release massive amounts of high-energy particles that are bombarded towards Earth. Fortunately we have a strong magnetic field (ionosphere), created by the planet’s molten iron core, which deflects these particles around us. Something which you can see visually with the aurora borealis in the north hemisphere and aurora australis in the south. However the strong solar storms that cause sun spots do disrupt our magnetic field in subtle yet important ways.
It has long been suspected that several species of cetaceans are capable of using the Earth’s magnetic field to help navigate over long journeys, often referred to by researchers as geomagnetism. Many species of animal have been shown to have such an ‘internal compass’, like most birds that must make precise annual migrations over thousands of miles every year. It is easy to test for this sense in birds by simply placing them in a box and artificially flipping the magnetic field surrounding it. However it is decidedly harder to trap a whale in a box (although that hasn’t stopped marine life parks from trying in the past). Therefore the extent to which they rely on geomagnetism has very much been left to theoretical debate, with researchers arguing whether their extensive migrations are a result of magnetic fields or their much more well documented acoustic navigation.
A bizarre connection
Whilst it may not be possible to test a whale’s sense of magnetism in a laboratory, a new mulit-discipline study has now given us a pretty definitive answer based on observations in the wild. This discovery was made after marine researchers from Duke University discovered an unusual pattern between beached whales and sun spot activity. Looking at a 31 year data set of gray whale strandings collected by NOAA (National Oceanic and Atmospheric Administration, US) lead author Dr Jesse Granger isolated incidents where the animals beached themselves in perfectly good condition with no sign of ill health or hearing damage. After searching for a reason behind these strandings she eventually discovered a strong overlap between these strandings and sun spots.
Realising that solar activity might play a role in this behaviour fellow researcher Sönke Johnsen got in contact with Dr Lucianne Walkowicz from Chicago’s Adler Planetarium to confirm their theory. As fate would have it Dr Walkowicz once dreamed of becoming a marine biologist before pursuing a career in Astronomy, so jumped at the chance to help. Collaborating together the team proved that there was in deed a strong statistical link between the two otherwise alien occurrences. Just like sun spot activity which waxes and wanes over 11 year cycles, the strandings also increased and decreased accordingly. Talking to the New York Times Dr Granger even went as far as saying “they showed the exact same cycle as the sunspots”.
Gray whales have one of the longest annual migration of any cetacean travelling an incredible 10,000 km a year. It now appears that this is in part due to their sense of geomagnetism which can obviously be impacted by solar activity. Initially Dr Granger assumed that the high energy particles resulting from sun spots were disrupting the ionosphere, which subsequently threw off the whale’s ability to read magnetic lines and get pushed off course. However she now believes that the storms might be directly influencing the whales’ magnetic sensors, by releasing huge bursts of radio-frequency radiation. Something that was also proved by further statistical analysis of the data.
A questionable correlation?
Whilst the statistical analysis used by the team is not under any question and does show a clear link between sunspot activity and strandings, some researchers are cautiously questioning the correlation. The main issue researchers have with the paper is that it makes some rather bold claims about the complex nature of cetacean strandings. After all it is the type of research that drilling and shipping companies latch onto to argue that their sound pollution doesn’t cause whales to beach, even though it definitely does. It is therefore important to remember that although this does prove some whales can use geomagnetism to navigate and can be run aground by solar activity, it is not the main reason most cetaceans get stranded.
Everything is connected
Regardless to the extent of which this study supports the role of geomagnetism in cetacean strandings, one thing it does confirm is that life on Earth is much more connected to cosmic forces in our solar system than we realise. Not only does the sun’s activity alter whale behaviour, it is also essential to all life on Earth providing us with the energy needed to sustain every living thing on the planet. Without the gravitational pull of the sun and moon we would also be left without the tides that have played a crucial role in the development of not just our planet, but also our civilisation. So next time you look up at the sun, just take a moment to think about the important impacts it is having on you, the ocean and even migrating whales.