Tag Archives: Nature

Ancient Water, Deep Life

18 Dec

I haven’t posted here as much as I have wanted to recently due to a combination of factors.  Firstly my laptop broke, secondly I’ve been busy at work now that the arm has healed up (x-rays of the fracture here), and thirdly I’ve also been conducting an osteoarchaeological side project.  (I’m also expertly, somewhat even academically, ignoring a slew of deadlines which are fast approaching for a few writing projects).  However this is just a quick post to say that there should be a few posts over the next month or so.  A few of these posts have been drafted earlier in the year and are half-finished, but it is hoped they’ll be finished shortly.

In the meantime, and in non-osteo news, I couldn’t help but notice two particularly interesting science articles on the BBC news website earlier today.  Both news articles are probably not new to geologists, oceanographers or geophysicists, but they have certainly piqued my interest.  There is evidence that biological life, in the form of microbes, have been found living at a depth of 2400m beneath the seabed off the coast of Japan.  Although the organisms are single-celled they do seem to manage to survive on a diet of hydrocarbon compounds whilst only expending low amounts of energy.  The microbes have been found in coring samples from an ancient coal bed system, which was drilled by the International Ocean Discovery program in 2012 in the Shimokita Peninsula, Japan.  Amazingly the drill was sent down through 1000m of seawater and through 2446m of rock under the seabed itself.  At such depths there is little water, limited nutrients, no light and no oxygen, yet life still survives.  Tantalizingly research still remains to be conducted on how the microbes came to be at this location and at this great depth.  Read the article here on the BBC.

The other science news article deals with water of a different order.  The world’s oldest deep water is present in a much greater volume than previously estimated.  Located within the Earth’s crust, where some of the oldest rock can also be found, ancient water has been sampled through boreholes and mines and the revised estimate of the volume suggests there is around 11 million cubic kilometres present in the crust.  The world’s oldest dated water has been located in present day Canada in a mine located 2.4km down into the crust, estimates put the water at around 1 billion to 2.5 billion years old (yup billion!).  The fact that the water is so old, and preserved so well, has surprised many and also revises the estimates of hydrogen produced on earth.  Previously it was thought that continental crust produced almost zero hydrogen compared to ocean crusts.  Again, the full article can be found here on the BBC (1).

Both news articles are the result of research coming from the currently ongoing 47th American Geophysical Union Fall Meeting in San Francisco (15th-19th December with a whooping 24,000 delegates!), which covers Earth and space science topics.  I’ll certainly be keeping an eye out for further news as this is incredibly interesting as scientific research continues to extend our knowledge of where, and how, life not only survives but seemingly thrives.

Notes

(1).  The scientific literature has not been referenced in this post but I will update once this becomes either available and/or when I have the time.

19/12/15 Update

In other extreme life news the New Scientist magazine has reported the filming of a fish (a possible snailfish) at the depth of 8143m below the surface at the Marianas Trench, in the Pacific Ocean.  The Marianas Trench is the deepest part of the world’s oceans, and the filmed footage of the snailfish at this extreme depth highlights once again how life can survive in hostile environments.  The intense pressure at this depth places severe limitations on the function of muscle and nerve tissues, however snailfish are known to survive in such intense pressure environments with another species, Pseudoliparis amblystomopsis, having been studied and recorded at depths of 7703m before.

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Ungulates Gnawing: Osteophagia & Bone Modifications

24 Oct

Osteophagia: Osteophagia is the act of ungulates (including giraffes, camels, cattle, etc.) chewing on another species skeletal remains to gain nutrition (particularly minerals such as phosphorus and calcium) that may be lacking in other parts of their largely vegetarian diets.  This includes the chewing of antlers, horns and ivory, as well as skeletal elements.  It is a relatively well documented animal behaviour that occurs across numerous taxa and across continents.

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I’ve been meaning to highlight this article by Hutson et al. (2013) for a while as it nicely illustrates the actions of animals in the archaeological record that can sometimes be interpreted, or mistaken, for a human or taphonomic origin.  Hutson et al. (2013) discusses the impact that ostephagia can have on archaeological contexts and carefully identifies the differences between large and small ungulate osteophagia-based actions.  Taking 12 individual and observed case studies of osteophagia examples recovered from modern field contexts in Australia, North America and Africa, the study highlights the different styles of bone modifications made by each species to help identify the often distinct bone modifications that they leave in their wake.  The case studies include examples of wildebeest (C. taurinus) bones having been gnawed by giraffes, elephant (Loxodonta africana) ivory gnawed by kudu or sable antelope, and a camel (C. dromedarius) radius fragment having been gnawed by a camel.

Hutson et al. (2013: 4140) notes that ‘previous studies have shown that ungulates gnaw both cortical and cancellous bone and elements in almost any state, from fresh to completely bleached, desiccated, and weathered”.  The favoured bones to gnaw during scavenging among ungulates are elements of the long bones, vertebrae, scapulae, skulls and ribs, and, if munching on long bones, the larger ungulates often position the axis of the bone ‘like a cigar held in a human mouth’ (Hutson 2013: 4140).

ostephagia 111 hutson etal13

This diagram shows porcupine gnawed B. taurus limb elements, where a) is the right tibia and b) is the left femur. Notice the what look like long striations, which are in fact gnawing lines (click to enlarge). Image credit: Fig 8 from Hutson et al. 2013: 4147.

Importantly, the authors differentiate the classes of ostephagia-based bone damage caused by large ungulates and compare it to the typical bone damage caused by carnivores and other primarily meat-eating scavengers, such as lions, panthers and tigers.  This comparative approach takes into account 10 separate features of bone damage often found on gnawed skeletal remains (including evidence of prey selection, bone selection, bone state, bone transport, tooth mark type and general morphology amongst others) and highlights the varied differences between the two behaviours of ungulates and carnivores (Hutson et al. 2013: 4148).  Perhaps of primary importance in this article is that fact that tooth morphology varies according to species and purpose, as such the authors explicitly highlight that, alongside this, the age of the individual animal, and thus the state of its teeth, gnawing the bone can affect the patterning expected (Hutson et al. 2013: 4147).

ostephagia hutson etal13

This rib was found at the fringe of a scatter of skeletal elements from one individual. Showing the distinctive forking and crushing of ungulate gnawing, this B. taurus rib was likely gnawed by cattle whilst still relatively fresh. Image credit: Fig 6. in Hutson et al. 2013: 4145.

Of course care should always be taken in the recording of gnawing evidence, as teeth in both humans and non-humans can wear down and gouging styles can vary.  However, the distinguishing marks made between ungulates during the act of osteophagia and the selectivity of active carnivores and scavengers is vital for the archaeologist as it can infer on the context of the gnawed skeletal remains.  This can help identify the fauna previously present on-site and the actions that took place based on replicating the known evidence.  The analysis of faunal bones at archaeological and palaeoanthropological sites should, of course, be used in conjunction with other taphonomy techniques to fully understand site formation.

All in all, this is an interesting paper that adds real depth to the taphonomic literature and should be of note to both archaeologists and palaeoanthropologists in interpreting the actions of both humans and non-humans during site formation.

Update 26/10/14

Osteophagia is just one method that mammals use to gain extra nutrients in their diet, another method is mineral lick.  As with osteophagia it has long been noted that animals will exploit their environments by eating or otherwise digesting natural soils, clays and rocks to gain elements (particularly salt) that may be missing in nutrient poor ecosystems (Lundquist & Varnedoe Jr 2006).  Mineral lick is particularly prevalent among giraffes, elephants, moose, cattle and tapirs (and other mammals) as a way to increase the amounts of minerals, such as potassium, calcium, sulfur, phosphorus, and sodium, in their diets.  Although the knowledge of so-called salt caves and their origin with animal behaviour is well know, it is thought that they are under-estimated in current estimates of their prevalence (Lundquist & Varnedoe Jr 2006: 18).  As such these natural landscape features should also be taken into account when understanding the formation and duration of palaeoanthropological and archaeological sites.

Bibliography

Hutson, J. M., Burke, C. C. & Haynes, G. 2013. Osteophagia and Bone Modifications by Giraffe and Other Large Ungulates. Journal of Archaeological Science. 40 (12): 4139-4149.

Lundquist, C. A. & Varnedoe Jr, W. W. 2006. Salt Ingestion Caves. International Journal of Speleology. 35 (1): 13-18. (Open Access).