Corsica mission: methodology

Wednesday 5 November 2014
popularity : 11%

Table of contents:

1. Context of the project
2. Objective
3. Partners and participants
4. Summary of the mission
5. Timing of the mission
6. Methodology
7. Sites description (one plan for each site)
8. List of participants
9. Sampling results for each site
10. Bibliography

Material list:
• Sampling material:
-  Zipped plastic bags,
-  2 elastic bracelet (to hang bags in the wrist) (Figure 4),
-  1 portable fridge (to transport samples),
-  Usual diving and safety gear.

Figure 4: plastic bags hanging on the wrist thanks to the elastic bracelet

• Conditioning material :
-  Falcon tubes of 50 ml (for the conditioning of M. truncata and C. inornata),
-  Zipped plastic bags (for the conditioning of L. cabiochiae/stictaeforme),
-  Tweezers,
-  Gloves,
-  Alcohol 95 %,
-  Pencil,
-  Permanent markers,
-  Paper towel,
-  Scotch tape,
-  Tracing paper,
-  Silica gel,
-  Boxes or bags to transport the samples.

In order to easily trace the samples’ origin, plastic bags must be previously identified, using permanent marker pen. This should be done in two locations of the bags in order to avoid erasure risk. During dives, 30 samples of the 3 species must be collected, and samples should be about 2 cm high. This should be done as followed: (i) for M. truncata breaking carefully a piece at the top of the colonies, (ii) breaking carefully a piece at the edge of the thallus for L. cabiochiae/stictaeforme, (iii) the whole individual must be taken for C. inornata.
Samples of M. truncata and L. cabiochiae/stictaeforme must be separated by at least 1 cm. Individuals of C. inornata collected must be separated by 50 cm.

Samples conditioning:
At the end of the sampling, the specimens are placed directly into a portable fridge for their protection until the arrival to the laboratory. Handling of samples is done with tweezers on a clean surface. Epibionts and epiphytes are removed in order to reduce ADN pollution that could bias the results of genetic analysis.
Samples of M. truncata are then put individually into Falcon tubes of 50 ml filled with enough « 95% ethanol » to cover the whole sample (10 ml is enough for small samples). After 1 to 24 h, this alcohol, is replaced by 25 ml of pure 95% ethanol (Figure 5).

Figure 5: conditioning of M. truncata in tubes of 50 mL

C. inornata samples are placed into Falcon tubes in a way to regroup samples for same site? in one tube. Tubes are prefilled with « 95% ethanol ». After at least 1 h (or the day after), the alcohol must be replace by some clean and pure alcohol.

Samples of L. cabiochiae/stictaeforme are placed individually in zipped plastic bags. Then those bags are filled with a desiccant « Silica gel » (silicon dioxide) in a way to cover the sample.

Figure 6: conditioning of L. stictaeforme/cabiochiae

Each bag or tube must be properly named on the outside (using a permanent marker, and covering the writing by adhesive tape to protect it). Moreover the name of the sample is written on a tracing paper using a pencil, and put inside the bag or tub. Sample’s name should respect the following model:

[program_code]_[site_code]_[date]_ D[depth]_[average depth]m_[species]_R[n°réplicate]_[name of the operato]

Example: CIGESMED_IRB_20141007_D1_28m_M.truncata_R07_RDDG

5. Timing of the mission ← o → 7. Sites description










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