The many (scientific) uses of penguin poop (Part II)

Tracking penguins in time

Having established where these awesome, possibly cuddly, penguins are, it is time to turn out attention to their history. This is going to be a relatively short post based on a very short article.  

Gentoo penguins (from Encyclopaedia Britannica) 

Historical records are limited especially concerning animals in remote habitats. If we want to know how many of them there where at a specific point in time, we’re going to have to resort to different measures. That’s what some researchers from the University of Science and Technology in China did.

The location they investigated is the Ardley Penisula in Antarctica. This is actually an island with a lake on it. Penguins roost around the lake and their droppings can be found on the surrounding rocks as well as in the lake where they are either deposited directly or indirectly by water flow into the lake. The map below (from the Australian Antarctic Data Centre) shows the location.

I have mentioned previously that penguin guano is high in phosphorous, nitrogen and other elements not regularly found in the environment in these concentrations. So these are the elements to test for. The researchers took a sediment core sample spanning around 3 000 years according to C13 dating. Then they measured that concentrations of certain elements in different sections:

We found that the concentration of elements such as sulphur, phosphorus (represented by P₂O₅), calcium (represented by CaO), copper, zinc, selenium, strontium, barium and fluorine in Y2 was much higher than in other lake sediments in the maritime Antarctic.

The relative concentrations of the elements stayed the same, indicating a common source – penguin droppings from the nearby colony. The concentrations in this lake where significantly higher than in surrounding lakes (that are presumably without penguin colonies).

The total concentrations varied however. They peaked between 1800 and 2300 years BP (before present = before 1950). This was a period with higher rainfall.

One thing I noticed was that the article does not mention penguin species. Of course, I would assume that it is relatively difficult if not impossible to distinguish between the droppings of different species, especially if they are all mixed up in the sediment! Still, it shouldn’t be a problem to mention the species currently living there.

Despite this being relatively unimportant to the point made by this study, I looked up the species living on the Ardley Penisula today at the Australian Antarctic Data Centre and they are Gentoo Penguin (depicted above), Chinstrap Penguin, Adelie Penguin and Macaroni Penguin. The first three are members of the Pygoscelis genus meaning they are presumably quite similar, especially in their droppings. The Macaroni Penguin is distinctively marked and warrants an extra image for this post (‘cause they’re cool!):

Macaroni Penguin (image from Wikipedia)

Now that we’ve established that penguin droppings can alter the sediment in the long run, keep your eyes peeled for the next instalment of The many (scientific) uses of penguin poop.

Links to the other parts: (further links to be edited)

Part I – Tracking penguins in (& from) space
Part III – How hard to penguins push? (20/8/2010)

Other links of possible interest:

March of the fossil penguins – a blog on fossil penguins for those interested in fossils and/or the history of penguins

Sun L, Xie Z, & Zhao J (2000). A 3,000-year record of penguin populations. Nature, 407 (6806) PMID: 11057656