standardization of environmental data and information - International ...

e applied. Please remember that they have to be adjusted, e.g. to the
ships manoeuvrability.
4.3. Size of the sampling area
You have to sample the total 2500-cm² area of the box corer.
Otherwise, you will have problems in complying with standard statistical
requirements.
4.4. Sediment horizons
Suck up the top water with a flexible hose and sieve it with a 250-
µm mesh. Any remaining water should be sucked up with, e.g., a turkey
baster and passed through the same 250-µm mesh size used for the top
water. Store this sample in a separate labelled container.
Three sediment horizons should then be separated, as follows:
a. Top sediment layer – depending on the sediment properties,
take off the top 1-2 cm;
b. 1-5 cm (2-5 cm) horizon, and
c. 5-10 cm horizon.
Measure with a ruler from the upper sediment edges for b and c.
Use a spoon or ladle to remove the sediment from the box carefully.
4.5. Mesh sizes of sieves
Use only 250-µm mesh-size sieves for all sediment horizons. In
case you need different size classes, you can again sieve the residue from
the 250-µm sieving according to your requirements. From our experience,
we learned that 500 µm is too large and resulted in a loss of about 45% of
the macrofauna 40 .
4.6. Sediment treatment during sieving
Use a good stainless steel table for a proper stand, and filtered
seawater. Use filters with changeable pore size so that they can be
employed also for meiofauna or plankton samples. Macrofauna samples
INTERNATIONAL SEABED AUTHORITY 349