I already described the generalities of my palaeontological work in Cyprus in this post. Here, I want to outline one of the main research projects – although it is stalled due to lack of funding and the related lack of free time, as with all my research projects.
The locality is in the Kakkaristra Formation in Nicosia. As you can see from the picture above, there is an enormous amount of shells there. You’re forced for a couple hundred meters to walk on all these shells, all dating back to the Pliocene. In palaeontology, we refer to this sort of locality as a Konzentrat Lagerstätte – an outcrop with an abonormally high concentration of fossils (contrast with a Konservat Lagerstätte, an outcrop with exceptionally preserved fossils).
In this case, the concentration is due to this locality representing the mouth of a fan delta. Back in the Pliocene, the Troodos Mountains had already risen above sea level (see my outline of Cyprus’s geological history). The Mesaoria Plain, between Troodos and the northern Kyrenia Mountains, and where Nicosia is located, was still underwater, although pretty shallow. A river, the Kakkaristra River, flowed down Troodos and into the shallow ocean beneath Troodos, where a rich marine community flourished. The community was marked by a high concentration of oysters, typical for a sediment-rich delta. When the latest uplift phase of Troodos happened, this community was uplifted as well, and left preserved for us to find.
One afternoon, I went with a couple of friends and collected two large garbage bags of shells from here. Only complete shells were collected. At home, I sorted them out to weed out any shells that have broken-off pieces, and the end result is a total of 473 perfectly analysable samples – this far surpasses the sample size any other studies I’ve read so far on this kind of research.
What exactly is this research? Species interactions. Over half of the shells collected have at least one sort of interaction preserved on them. Some example below.
I am catalogging all of these, but the bulk of the work involves the statistical analysis and interpretation of the interactions. The shells were all photographed against graph paper, used to calibrate the program to be able to measure the area of bryozoan and sponge encrustation. Barnacles, drill holes, and tubeworms are counted. In addition, the shell is treated as a geographical area and I am logging the spatial distribution of all the interactions, to see if there is any significant preferences in where the encrustations and predations occur. These would be indicative of palaeoenvironmental conditions or even of whether the encrustation happened pre- or post-mortem.
As I said, it’s a stalled project like the rest of them, but once I get the opportunity to get to work on it more, there are several additional avenues for the research to go down.
- The mass of shells these were collected from suffer from several taphonomic biases. For one thing, only large and heavy benthic molluscs are preserved, leading to 97% of the collected shells being one oyster species, Ostrea edulis, because anything smaller was swept away further by the current that deposited these shells. In addition, these shells are time-averaged, i.e. they don’t come from a single slice of time but are a jumbled-up mix of several communities that got swept together. Luckily, across a small prairie from this outcrop, lies a wall that goes on for 400 meters and that has all the stratigraphic layers and is relatively unaffected by these biases. Collecting systematically from here would give us an unbiased look at the encrustation rates, and would allow me to investigate encrustations on smaller organisms.
This research is done in collaboration not with other palaeontologists, but with my close marine biologist colleague who is working on characterising the coral and general marine communities around Cyprus, including the patterns exhibited by bryozoans and other encrustating organisms. My research gives him a deep-time perspective on these, in some cases even allowing a direct comparison of encrustation rates and patterns. There is another locality from archaeological time that gives us a higher resolution on this, but I’m not allowed to give any more details on that one because we still haven’t published it…