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VOL. 76 (2), 189-208, 2010 THE IGNORED STOWAWAYS: WORLDWIDE...

s = 1- (mTBT r/mTBTs)

where mr and ms are the Malthusian fitness of TBT-resistant
TBT TBT

and TBT-sensitive cells measured in non-selective conditions (i.e.

BG-11 medium), respectively.

2.5. Growth of TBT-sensitive and TBT-resistant cells
2.5. on antifouling paint

Bottom of 6 wells-dish plates (Nunclon Delta Surface, Danmark)
was painted with TBT- antifouling paint (Hempel, Polinya, Barcelona,
Spain). Twenty-four hours latter, cell inoculums of 5 × 105 wild type
TBT-sensitive cells or TBT-resistant mutants were respectively
transferred to antifouling-painted plates with 10 ml of BG-11 fresh
medium. Three plates of sensitive and three plates of resistant cells
were maintained at 20º C under continuous light of 60 mol photom
m–2 s–1 over the waveband 400-700 nm. Cultures were observed for 15
days and the final number of cells was counted using a Uriglass
chambers and an inverted microscope (Zeiss Axiovert 35).

3. RESULTS

3.1. Microalgae of biofouling recovering the underwater
3.1. body of ships

Numerous coastal and oceanic microalgae species proliferates on
bottoms of ships directly on TBT antifouling paint (Figure 2). Most
abundant species were: i) diatoms (Bacillariophyta) from genus
Navicula, Nitzschia, Asterionella, Amphora, Chaetoceros, Thalassiosi-
ras and Rhizosolenia; ii) Dinoflagellates from genus Prorocentrum,
Scrippsiella and Amphidinium; iii) Haptophyta from genus Prim-
nesium and Chrysochromulina; iv) Chlorophyta from genus Tetra-
selmis and Dunaliella; v) cyanobacteria (Cyanophyta) from genus
Synechococcus; vi) Cloroxibacteria from genus Prochloron. These mi-
croalgae were viable in spite of their contact with the antifouling
paint. In addition, resting phases (i.e. dinoflagellates cyst, diatom
spores) and early stages of macroalgae (i.e. Fucus, Laminaria, Chon-
drus, Codium and others) were also observed.

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