Buried waterlogged environments provide unique conditions for organic materials such as wood, bone, antler, textile, skin and plant remains to be preserved for millennia, partly due to the low oxygen levels. Conditions in open seawater can, in the absence of wood boring organisms (see wreckprotect.eu) also preserve these materials for many hundreds of years. However, deterioration of organic material can occur in oxygen free (anoxic) environments due to the activity of anaerobic bacteria. Research into the reburial of archaeological materials in the marine environment has shown that the rates of organic turnover (deterioration) are dependent on sediment type and their pore water composition (http://www9.vgregion.se/vastarvet/svk/reburial/index.htm). The project will develop tools and methods to:

•    improve sampling techniques for sediments, not only for the purposes of this project, but archaeology in general (dating, pollen and other environmental analyses). Currently available diver operated coring devices can be notoriously difficult to use in terms of deployment, retrieval and obtaining deep and undisturbed sediment cores. A diver deployable vibrocore-type coring system, will be constructed and tested by AKUT and NM, which can sample sediments down to a maximum sediment depth of 50 cm and without disturbing the surface layers of sediment which are very difficult to sample due to their often mobile nature. The corer will be constructed in such a way that discrete layers within sediments (taken both vertically and horizontally) can be easily sub sampled in order to characterize both sediment type and porewater composition in the laboratory. The device will be used for ground truthing other elements of this and other work packages.

•    develop a data logging system which can be deployed for periods of up to six months to assess pore water composition of sediments in situ to a maximum sediment depth of 50 cm. Proposed parameters to be measured are dissolved oxygen, sulphide content, pH, redox potential and methane, which in combination provide information on the biogeochemical process on going in the sediment and their effect on organic material turnover. This data logger will be developed by partner 3 (UNI), who are world leaders in development of microsensor technology for use in underwater and marine environments

The developed tools will be used to obtain sediment samples and monitor conditions on the test sites in order to better understand why artefacts are so well preserved, archaeologically speaking, and determine which sediment types offer the optimal conditions for preservation should sites be preserved either in situ or through re-burial. The results of this environmental monitoring will also be compared and contrasted with microscopic analysis of representative samples of archaeological wood, carried out by partner 8 (UGOT) from the sites in order to contribute to our understanding of the effects of the environment and deterioration process of waterlogged archaeological wood. Similarly the results will be compared and contrasted with the data obtained by the 3D sub bottom profiler. The EU financed project Baltic Gas (http://balticgas.au.dk/balticgasaudk/) has shown the possibility of monitoring methane development with similar equipment. In this manner it may be possible to use this tool not only to localise artefacts but also characterise the biogeochemical processes on-going in the sediment to assess the preservation capabilities of sediments.