Microfauna (Ciliates) in sediments.

The sediment core is obtained by inserting 36 x 297 mm plastic core into the sand, closing with a rubber corks. The core is placed in the lab 30 minutes after collection, and sliced in 2 cm sections to 20 cm sediment depth. Subsamples for examination are chosen by inserting into each sediment slice a 12 x 20 mm plastic mini-core, giving a subsample volume of 2,26 ml. The subsamples are fixed in 10 ml 1% glutaraldehyde solution (diluted with filtered water from the sampling location). The samples are then stored in refregirator in 50 ml plastic containers at 4°C.
Within two days from subsamples separation, the sediment slices are washed, by shaking and then allowed to stand for approximately 5 s. A 5 ml sample of water is removed with an Eppendorf pipette. The remaining sample is then supplemented with adding 5 ml 1% glutaraldehyde solution, and after shaking another 5 ml of supernatant is removed. The procedure is repeated 5 times, resulting in 25 ml of material from the washed sample. Assuming that ciliates were randomly distributed in the solution immediately after shaking, 5 rinses removed 97% of the ciliates present in the initial sample, because 0,55 x 100 = 3,1% of the original sample remaining.
After shaking the obtained supernatant 10 ml is placed into plexi glass sedimentation column for at least 6h. After this time settled ciliates are counted using light microscopy at a magnification of 200x and 400x. Then cells are photographed, measured and identificated to the lowest taxonomic level. Abundance is presented in number of specimens per 2,26ml of sample. The biomass is calculated using the conversion factors from the literature: 0,11 (ed. Edler 1979) and presented in ľg C/cm3.
For the examination of living material, two sediment cores are extracted and sliced as described above, but not fixed. Sediment sections from cores were slipped with minimal disturbance to a 50 ml plastic recipient and were immediately carried to the laboratory. Extraction of the ciliates was made by the sea-water ice method (Uhlig 1965). The cells were counted by removing them one by one with a pipette under the dissection microscope and individual ciliates were photographed using light microscopy at a magnification of 200x or 400x. Selected ciliates were stained with protargol according to the method of Wilbert (1975.) (Foissner et al.1999). A mixture of Bouin's fluid with saturated mercuric chloride (1:1) was used as fixative. Photos and durable slides have been used to identify species.
Literature:
Carey P.G. (1992) Marine Interstitial Ciliates. Chapman & Hall. 1-351.
Edler L.(ed.) (1979) Recommendations on methods for marine biological studies in the Baltic Sea. Phytoplankton and chlorophyll. National Swedish Environment Protection Board. 1-38.
Foissner W., Berger H., Schaumburg J. (1999) Identification and Ecology of Limnetic Plankton Ciliates. Bavarian State Office for Water Management. 1-793.
Uhlig G. (1965) Untersuchungen zur Extraktion der vagilen Mikrofauna aus marinen Sedimenten. Akademische Verlagsgesellschaft Geest &Portig K.-G..151-157.