Diapositiva 1

1
An example of proliferation of marine
phytoplankton (Article 9, Directive 2006/7/EC)
Discolorations caused by accumulation of the
surf-diatom Attheya armatus observed in several
sandy beaches in Gran Canaria (Canary Islands)
during 2000-2004.
Macroscopical appearance of discolorations of
Attheya armatus
Discolorations of Attheya armatus at low tide.
2

• Investigations were undertaken in order to
  determine the identity of discolorations.
  Adequate Management Measures were implemented,
  according to the Directive 2006/7/EC
• Sampling and microscopical observation of
  discolorations.
• 2. Taxonomic identification of samples.
  Surf-diatom Attheya armatus (T. West) Crawford
  was the only species responsible of the
  discolorations. As A. armatus is a harmless
  species for human health, bathing prohibition was
  not necessary.
• 3. A preliminary report was submitted to Local
  Authorities.
• A long-term study was carried out for five years.
  
• 5. Results were reported in a published paper by
  Ojeda O Shanahan (2005) (1)

Discoloraciones por acumulaciones de la diatomea
bentónica epipsámica Attheya armatus (Centrales,
Bacillariophyta) en playas de arena del S y SW de
Gran Canaria (Canarias, España). Alicia Ojeda
Rodríguez1 Leopoldo O' Shanahan Roca1 1
Instituto Canario de Ciencias Marinas. Gobierno
de Canarias. P.O. Box 56. TELDE. 35200 LAS
PALMAS (CANARIAS, ESPAÑA). aojeda_at_iccm.rcanaria.e
s loshanan_at_iccm.rcanaria.es
3
RESULTS. Microscopic Observations and Taxonomic
identification Discolorations comprised huge
aggregation of cells. Cells were rectangular in
girdle view and elliptical or oval in valve view,
with two lobed plates plastids, forming chains of
7 to 14 cells, with an average of 10 cells.
Valves faces were a little elevated in the centre
and at margins. Apical axes ranged from 23 to 32
µm and the transapical axis from 11 to 15 µm.
2
1
1. Attheya armatus. Scale bar 10 µm. Girdle
view with two plastids in each cell of the chains
and a single cell in valve view (black arrow)
2. Chains of cells forming aggregates. 3. A
single cell in valve view showing the typical
spines (black arrows)
3
Olympus BX41 light microscope at 40X, 60X and
100X. Identification was based on Round et
al. (1990) and Crawford et al., 2000).
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• Alicia Ojeda Rodrígueza Leopoldo O Shanahan
  Rocaa,b . 2005. Discolorations of the surf zone
  diatom Attheya armatus (Centrales,
  Bacillariophyta) on sandy beaches in Gran Canaria
  (Canary Islands, Spain). (Discoloraciones por
  acumulaciones de la diatomea bentónica epipsámica
  Attheya armatus (Centrales, Bacillariophyta) en
  playas de arena del S y SW de Gran Canaria
  (Canarias, España)). VIERAEA Vol. 3351-58.
• a Canary Islands Institute for Marine Sciences
  (Instituto Canario de Ciencias Marinas) Gobierno
  de Canarias. P.O. Box 56. TELDE. 35200 LAS PALMAS
  (CANARIAS, ESPAÑA).
• b  corrresponding author loshanan_at_iccm.rcanaria.e
  s