Download Algal toxins in Scottish waters: the first association of domoic acid

Algal toxins in Scottish waters: the first association of domoic acid
with the diatom Pseudo-nitzschia pseudodelicatissima complex in
the North East of Scotland
Eileen Bresnan, Jean-Pierre Lacaze, Sheila Fraser, Lyndsay Brown, Ana-Luisa Amorim and Kathryn Cook
Marine Scotland Science, Marine Laboratory, 375 Victoria Road, Aberdeen AB11 9DB
E-mail: [email protected]
Introduction
How to identify Pseudo-nitzschia?
•
Diatom genus Pseudo-nitzschia (Peragallo)
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Light microscopy (LM) cannot identify Pseudonitzschia cells to species level
•
Routinely observed in Scottish waters
•
•
Two species within genus (P. australis and P.
seriata) confirmed as producers of domoic acid
(DA)1
LM can only separate cells into two different
size classes (</> 5µm diameter)
•
Electron microscopy or molecular methods
required to confirm identification
•
DA toxin
poisoning
•
High concentrations of DA closed offshore scallop
fisheries from 1998 – 20051
•
DA detected in faeces and urine of seals along the
east coast of Scotland 2
•
2008 – Study at Stonehaven ecosystem monitoring
site considered if zooplankton could act as a
vector for DA in Scottish waters
responsible
for
amnesic
shellfish
Light micrograph of Pseudo-nitzschia cells
Enlarged central portions of
Pseudo-nitzschia cells
P. seriata
Transmission electron micrograph
of Pseudo-nitzschia cells
P. australis
Algal toxins in Scottish waters: the first association of domoic acid
with the diatom Pseudo-nitzschia pseudodelicatissima complex in
the North East of Scotland
Study site
•
Stonehaven monitoring site
sampled weekly since 1997
•
Temperature, salinity,
and plankton measured
•
Calanus was sampled during 2008
for DA analysis
•
Liquid chromatography – mass
spectrometry – mass spectrometry
(LC-MS-MS) was used
Toxin data
is
nutrients
Latitude
60N
58N
Stonehaven
The copepod Calanus
Pseudo-nitzschia cells counts and DA concentrations in Calanus at the
Stonehaven monitoring site in 2008.
56N
54N
-8W
-4W
Longitude
•
DA does accumulate in copepods at Stonehaven
•
A maximum concentration of 11 ρg DA. copepod-1 was recorded in July
•
Diversity of the Pseudo-nitzschia bloom during July was examined
0W
Algal toxins in Scottish waters: the first association of domoic acid
with the diatom Pseudo-nitzschia pseudodelicatissima complex in
the North East of Scotland
Structure of Pseudo-nitzschia cells from July bloom
Identification of Pseudo-nitzschia cells
Whole Pseudo-nitzschia cell
•
A JEOL JEM 1400 Plus TEM was used to examine cells
•
Morphological structures on Pseudo-nitzschia were measured
•
Cells were identified as the recently described
plurisecta3
•
This is a species within the P. pseudodelicatissima species complex
•
Blooms of this species were previously observed in Scottish waters
following an extensive Karenia mikimotoi bloom.
•
This is the first association of this species with DA accumulation in
Scottish waters
Pseudo-nitzschia
Acknowledgements
Central Interspace
(CI)
Poroids
Fibulae
•
The authors would like to thank Mr. Kevin McKenzie at the Electron Microscopy
Unit, Institute of Medical Sciences, University of Aberdeen for his assistance.
•
This project was funded as part of the Scottish Government’s schedule of service
ST03p and ROAME AE1198.
Striae
Morphological measurements
Length
(µm)
Width
(µm)
CI
68
1.2 – 1.5
Y
Fibulae
(in 10µm)
Striae
(in 10µm)
Poroids
(in 1µm)
23-25
39 – 43
5-6
References
•
•
•
J., Green D., Davidson K., Bolch C. and Bates S. (2004) J. Phycol., 40, 622 – 630.
A. and Frame E. (2010), Harmful Algae, 9, 489 – 493.
3Orive E., David H. and Miguel I. (2013), J. Phycol. 49, 1192 - 1206
1Fehling
2Hall