x Abu Dhabi, UAEThursday 27 July 2017

6,000-year-old skeleton key to Abu Dhabi’s past

The 6,000-year-old remains of a humpback whale were found in Mussaffah in 2006 and the near-complete skeleton has offered scientists important clues as to the climate then – and the sea level. The full results of their research are about to be made public, reports Daniel Bardsby

A humpback whale skeleton found in Abu Dhabi in 2006 sheds light on the climate and sea level during that time. Photo courtesy Dr John Stewart
A humpback whale skeleton found in Abu Dhabi in 2006 sheds light on the climate and sea level during that time. Photo courtesy Dr John Stewart
For fossil hunters, there are not many tasks more challenging than removing the 6,000 year-old bones of a humpbacked whale from the ground without damaging them.
That was exactly what a team of researchers had to do when a whale skeleton was discovered in Abu Dhabi several years ago.
It was found, in 2006, by oil industry geologists in what is now the Musaffah industrial area.
“One of the more exciting parts was removing it from the ground,” recalls Dr John Stewart, one of the scientists involved. “It involved a crane and the skull was over one-and-a-half metres wide and two-and-a-half to three metres long.
“It was covered in plaster of Paris and it was a bit of an engineering challenge getting the whole thing out of the ground.”
Seven years on, full details of that remarkable find will soon be presented to the scientific community.
Dr Stewart, a senior lecturer in palaeoenvironmental reconstruction and environmental change at Bournemouth University in England, is preparing a detailed study of the massive skeleton for publication, a follow-up to the 2011 initial description of the find he co-wrote with 14 other researchers.
“We’re describing it more fully – all the anatomical bits. It’s all there – the skull, the two jaw bones, the two forelimbs – what you might call the flippers, the ear bones, the vertebrae, the ribs,” he said.
Disappointingly, the UAE’s searing heat had long since destroyed creature’s DNA, making genetic analysis impossible. Instead, the researchers are looking for diatoms, microscopic algae that could yield further information about the natural history of the time. In earlier studies, barnacles were found around the face, jaws and flippers of the mammoth creature.
The dead creature came to rest after its body was blown into an ancient lagoon, with decomposition gases in its stomach having caused it to float in upside down.
Of key interest were the microfossils of tiny creatures found with the bones, as these indicated the lagoon was far saltier than similar present-day areas of water in the emirate.
“When you get very saline water, you get a lot less species. When you have harsh conditions, there’s a lot less things that like it. We had a very impoverished fauna. The easiest way to explain that is higher salinity.”
This confirmed scientists’ existing belief that the Abu Dhabi of six millennia ago was more arid than now – and suggested that at that time the deserts that characterise modern-day Arabia were just developing.
“It was getting pretty dry. It coincides with a high sea level, a little bit [higher than at present],” said Dr Stewart.
Indeed according to Dr Mark Beech, one of Dr Stewart’s co-researchers on the whale project and cultural landscapes manager in the Historic Environment Department at Abu Dhabi Tourism and Culture Authority, this higher sea level – about 1.3 to 1.4 metres higher than at present – is one of the most interesting aspects of the whale study.
It indicates what might happen if global warming causes further melting of the polar ice caps and significant sea level rises.
“It’s something to think about when planning future settlements by the sea,” said Dr Beech. He hopes that ultimately the whale bones will be put on public display.
Turn the clock back about two millennia further and what is now Abu Dhabi, along with other parts of Arabia, was quite different. In the early Holocene, 7,000 to 8,000 years ago, the area was much wetter.
“We’re talking about the time when there were a lot of humans all over Arabia. In the Empty Quarter, you find a lot of archaeology that’s probably from the early Holocene when there was a lot more human activity,” said Dr Stewart.
So what caused Abu Dhabi’s climate to heat up thousands of years before human activity would start to have an appreciable impact on world temperatures? That, concedes Dr Stewart, is a tricky question.
“I don’t know is the straight answer,” he says, adding that “it’s hard to believe it’s not related to something much bigger in scale.”
Changes in ocean currents and monsoon patterns are likely to have been key factors.
Dr Stewart and others have also written about Abu Dhabi’s natural history much, much further back, and this earlier research vividly demonstrates how dramatic have been the changes in the Emirate’s climate and natural history over the ages.
Much of the knowledge is based on fossils from about eight million years ago – the late part of what is known as the Miocene era, which ran from 23.8 to 5.3 million years ago. At that time, the climate was also a lot wetter than now and large beasts, similar to those now found in East Africa, still roamed the Arabian peninsula. There were four-tusked elephants, ostriches, hyenas, crocodiles and a long-necked cormorant-like bird, to name but a few.
“Back in the Miocene this was to do with the rainfall patterns of the time. It was pre-ice age, so it was wetter,” said Dr Stewart.
They are just a snapshot, but the building evidence about Abu Dhabi’s wetter past demonstrates how much conditions can change – and how that depends in large part upon whether the planet is in the grip of an ice age or not. Ice ages tend to be drier because of the large amount of water tied up in polar ice caps.
“We saw the initiation of the deserts on the whale site, and prior to that it was a lot wetter.
“Prior to that, it was probably drier in the ice ages. Much further back, 10 million years ago, it was wetter.
“The take-home message from these two projects is that there’s a lot of climate change recorded in the sediments of Abu Dhabi.”
newsdesk@thenational.ae