Details:

Journal Title:
Harmful Algae
Personal Author:
Louw, Deon C. ; Doucette, Gregory J. ; Lundholm, Nina
Louw, Deon C. ; Doucette, Gregory J. ; Lundholm, Nina Less -
NOAA Program & Office:
NOS (National Ocean Service) ; NCCOS (National Centers for Coastal Ocean Science)
NOS (National Ocean Service) ; NCCOS (National Centers for Coastal Ocean Science) Less -
Description:
The Benguela upwelling system, considered the world’s most productive marine ecosystem, has a long record of potentially toxic diatoms belonging to the genus Pseudo-nitzschia. Species of Pseudo-nitzschia were reported as early as 1936 from the northern Benguela upwelling system (nBUS). For the current study, long-term phytoplankton monitoring data (2004–2011) for the Namibian coast were analysed to examine inshore and offshore temporal distribution of Pseudo-nitzschia species, their diversity and ultrastructure. The potentially toxigenic P. pungens and P. australis were the dominant inshore species, whereas offshore Pseudo-nitzschia showed a higher diversity that also included potentially toxic species. During a warming event, a community shift from P. pungens and P. australis dominance to P. fraudulenta and P. multiseries was documented in the central nBUS.

A case study of a toxic event (August 2004) revealed that P. australis and P. pungens were present at multiple inshore and offshore stations, coincident with fish (pilchard) and bird mortalities reported from the central part of Namibia. Toxin analyses (LC–MS/MS) of samples collected from June to August 2004 revealed the presence of particulate domoic acid (DA) in seawater at multiple stations (maximum ∼180 ng DA/L) in the >0.45 μm size-fraction, as well as detectable DA (0.12 μg DA/g) in the gut of one of two pilchard samples tested. These findings indicate that DA may have been associated with the fish and bird mortalities reported from this event in the nBUS. However, the co-occurrence of very high biomass phytoplankton blooms suggests that other explanations may be possible.


Keywords:
[+]
Mortality Pseudo-nitzschia Species Sea Birds Shellfishes
Source:
Harmful Algae, 75, 118-128
DOI:
https://doi.org/10.1016/j.hal.2018.04.008
ISSN:
1568-9883
Publisher:
Elsevier BV
Document Type:
Journal Article
Rights Information:
Accepted Manuscript
Rights Statement:
This manuscript is made available under the Elsevier user license https://www.elsevier.com/open-access/userlicense/1.0/
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:3a8c448d912b6415b4cd21027448073661849b46e230fbb7fd2f9c1a9d19c846
Download URL:
https://repository.library.noaa.gov/view/noaa/50826/noaa_50826_DS1.pdf
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