ADaM is short for "Aachener Daphnien-Medium" and is an easy to prepare, well-established medium for a variety of Daphnia and other limnic zooplankton species. Internal analysis in the AQUA laboratory has revealed the medium is virtually free from dissolved organic carbon (DOC), nitrogen (N), and phosphorus (P); it is therefore also suited for stoichiometric studies. The following recipe is based on the original publication by Klüttgen et al., with a modified selenium content first mentioned in Ebert et al..
To prepare ADaM, a high quality sea salt for scientific purposes is needed. Specifically, two sea salts have been frequently used in laboratories all over the world to prepare ADaM (this section will be updated soon to accommodate purchase links):
- Crystal Sea® Bioassay Laboratory Formula (Marine Enterprises International; Baltimore, MD, USA)
- hw-Marinemix® professional (Wiegandt; Krefeld, Germany)
To complete the medium, three stock solutions are needed. They should be prepared in quartz glass bottles using Type I purified water (e.g. Milli-Q water) and autoclaved after visible solution of the compounds. Stock solutions A and B can be prepared as 1 litre, while for stock solution C, 100 mL suffice.
|A||CaCl2 • H2O||117.60|
The medium itself is prepared by first dissolving sea salt in distilled water using a magnetic stirrer for at least 15 minutes and subsequently adding stock solutions A, B, and C (in this order).
|Final volume (L)||Sea salt (g)||Stock solution A (mL)||Stock solution B (mL)||Stock solution C (mL)|
The finished medium should be aerated through a 0.22 μm polystyrene filter for at least a day before use and kept in darkness (e.g. by covering it with aluminium foil) to minimize bacterial growth.
- Klüttgen, B., Dülmer, U., Engels, M. & Ratte, H.T. (1994) ADaM, an artificial freshwater for the culture of zooplankton. Water Research, 28:3, 743–746. DOI: 10.1016/0043-1354(94)90157-0
- Ebert, D., Zschokke-Rohringer, C.D. & Carius, H.J. (1998) Within- and between-population variation for resistance of Daphnia magna to the bacterial endoparasite Pasteuria ramosa. Proceedings of the Royal Society B, 265:1410, 2127–2134. DOI: 10.1098/rspb.1998.0549