CODENET - Notes on collection/sending of water samples for culture isolation

Collection

• It is best to send samples as soon as possible after collection - if sampling is conducted on a cruise, it may be best to leave collection as late as possible;
• Collection methods need not be technologically advanced - dipping a bucket over the side is acceptable;
• If facilities are available to determine cell densities/chlorophyll maxima in situ, samples should be collected at the highest possible cell concentration, if not, guess;
• Any information about sampling is useful - location, date, depth, water temperature, etc.;
• Observations of species assemblages made prior to sending would give us an idea of what to expect in the sample, and would help identify those species which do not survive in the post.

• Whenever possible, store samples prior to sending in glass/clear plastic vessels in the light, and leave the lid at least partly open to allow gaseous exchange. Store at a temperature as close as possible to sampling temperature - room temperature is usually OK.

• Small volumes of water are easier and cheaper to send, but high cell numbers increase the chances of survival, so concentration of cells in the water samples, particularly when cell density is very low, may prove useful;
• Filtration must be gentle to avoid damaging cells. 10µm nylon mesh is probably best (we can provide this if necessary).

• Send samples in a strong plastic container - small mineral water bottle, centrifuge tube, plastic culture flask, etc. Ensure the lid is well sealed with tape. It is probably best to fill containers completely - this may help reduce mechanical agitation during postage. Wrap containers in lots of padding and send in padded envelope/small box.
• If possible, send by express courrier delivery - we can refund any expenses incurred. Please let us know when samples have been sent, so we know when to expect delivery.