Regardless of the sampling device used, samples may be initially processed in the field or returned to the laboratory.
Standard benthic techniques should be followed (Holme and McIntyre 1984, Mudroch and MacKnight 1994). samples are initially washed on a 0.5 or 1.0 mm mesh sieve that retains the infauna.
The sieve contents (infauna, seagrass material detritus, etc.) are placed in a plastic bag or jar and a 5% solution of buffered formalin (= 5 parts full-strength formaldehyde [37%] to 95 parts water) is added to fix the invertebrates.
Rose bengal stain typically is added to the full-strength formaldehyde at 4 g stain per liter of formaldehyde before it is diluted.
This stains the invertebrates a bright pink color and facilitates the sorting process.
In most cases, we recommend that the seagrasses and as much as is practical of the other extraneous material retained on the sieve be carefully removed, cleaned by hand of any infauna, and discarded.
In some cses, it may be desirable to retain the seagrass parts for estimation of seagrass habitat structure.
The removal of unneeded material minimizes the amount of formalin needed to fix the sample.
Thesample will be properly fixed after 2 or 3 days in formalin if it has been well mixed, and can then be further processed.