Relevant parameters for OxyQuant calibration sediment cores:
| Parameter | Importance |
|---|---|
| environmental setting | The sediment cores should be located in a pelagic environment, meaning open and deep marine conditions as far as possible. Settings on continental margins are acceptable as long as they are not located in restricted environments surrounded by continents. Water depths should be below at least 500 m, better even below 1000 meters. |
| pore water data available? | Pore water analyses such as dissolved O2 are very helpful, but not required. |
| redox front known? | Knowledge about the depth of the redox front (zero O2) is currently not essential. However, if it is not known it must at least be likely that the redox front lies within the Holocene sediment layer. If the depth of the redox front is not yet established I will try to determine it with the help of the abundance of redox sensitive metals. |
| redox front in Holocene layer? | If the depth of the redox front is known it must be well within the Holocene layer. If it is not known, then it must at least be likely within the Holocene layer. |
| ancillary measurements? | Further existing or planned sediment analyses are desirable, but not essential. A sediment core description is essential, and a cruise report desirable. |
| specific BWO or productivity range? | At the moment I require sediment cores from all ranges of BWO and biological productivity, but particularly in the low BWO range. |
| other parameters? | At the moment I have no constraints on further sediment parameters such as sedimentology or sedimentation rates. However, a presence of foraminifera tests (both planktic and benthic) and fish debris is desirable. |
| sample size? | For the planned detailed investigations it is important that a certain amount of sediment is available from each site. Ideally, I would have one sample every 2-5 cm (maximum 10 - 15 samples) per core. Each sample should ideally contain 10-20 cm³ of sediment, but 1-2 cm³ may already be enough for the more sample efficient investigations. |
In summary, the ideal sediment core would be, for example, a 50 cm long Multi or Kasten core from a location with intermediate bottom water oxygen concentrations, with available pore fluid O2 concentrations falling to zero within the core, and with some age control showing that the whole core is of Holocene age.
Other sediment cores are acceptable if they fulfil most of the above criteria.