First Evidence of the Toxin Domoic Acid in Antarctic Diatom Species

Abstract

The Southern Ocean is one of the most productive ecosystems in the world. It is an area heavily dependent on marine primary production and serving as a feeding ground for numerous seabirds and marine mammals. Therefore, the phytoplankton composition and presence of toxic species are of crucial importance. Fifteen monoclonal strains of Pseudo-nitzschia subcurvata, a diatom species endemic to the Southern Ocean, were established, which were characterized by morphological and molecular data and then analysed for toxin content. The neurotoxins domoic acid and iso-domoic acid C were present in three of the strains, which is a finding that represents the first evidence of these toxins in strains from Antarctic waters. Toxic phytoplankton in Antarctic waters are still largely unexplored, and their effects on the ecosystem are not well understood. Considering P. subcurvata’s prevalence throughout the Southern Ocean, these results highlight the need for further investigations of the harmful properties on the Antarctic phytoplankton community as well as the presence of the toxins in the Antarctic food web, especially in the light of a changing climate.

In contrast to diatoms, cryptophytes are susceptible to iron limitation, but not to ocean acidification

“…Hence, we collected samples for DA (dissolved and particulate forms) measurements as described in Geuer et al (2020). In contrast to the study by Olesen et al (2021), which reported the presence of DA in several P. subcurvata strains, no DA was extracted from the cells and the culture medium of all our treatments, indicating that our P. subcurvata strain was unable to produce DA (data not shown).…”

Update of the Planktonic Diatom Genus Pseudo-nitzschia in Aotearoa New Zealand Coastal Waters: Genetic Diversity and Toxin Production

“…Domoic acid is the primary ASP-causing toxin, with multiple studies assessing DA production by Pseudo-nitzschia . In contrast, there are only a few studies which assess DA isomer production by Pseudo-nitzschia strains: iso-DAs A and B from P. delicatissima , P. multiseries [ 48 ], and P seudo-nitzschia seriata [ 49 ], iso-DA C from P. australis [ 50 , 51 ] and P. subcurvata [ 52 ], and epi-DA and iso-DAs A and D from P. plurisecta [ 53 ]. This is the first study to screen, and report, iso-DA E production by Pseudo-nitzschia strains.…”

“…Apart from DA, the present study detected all, or a combination of, the tested DA isomers (epi-DA and iso-DA A–E) from all P. australis and P. multiseries strains analysed. Recently, Olesen et al (2021) [ 52 ] reported relative amounts of DA and iso-DA C in three P. subcurvata strains. The authors reported that the proportion of DA tended to be lower than that of iso-DA C (DA:iso-DA C = 34–49%:51–66%) [ 52 ].…”

“…Recently, Olesen et al (2021) [ 52 ] reported relative amounts of DA and iso-DA C in three P. subcurvata strains. The authors reported that the proportion of DA tended to be lower than that of iso-DA C (DA:iso-DA C = 34–49%:51–66%) [ 52 ]. Unlike the results for P. subcurvata strains [ 52 ], the present study found that the proportions of DA of P. australis and P. multiseries strains tended to be higher than those of iso-DA C [ P. australis , DA:iso-DA C = 44.4–91.5%:4.8–54.1%; P. multiseries , 93.9–96.5%:2.3–3.1%], suggesting that the ratio of DA to DA isomers varies among species.…”

“…The authors reported that the proportion of DA tended to be lower than that of iso-DA C (DA:iso-DA C = 34–49%:51–66%) [ 52 ]. Unlike the results for P. subcurvata strains [ 52 ], the present study found that the proportions of DA of P. australis and P. multiseries strains tended to be higher than those of iso-DA C [ P. australis , DA:iso-DA C = 44.4–91.5%:4.8–54.1%; P. multiseries , 93.9–96.5%:2.3–3.1%], suggesting that the ratio of DA to DA isomers varies among species. In addition to this, Rhodes et al (2004, 2006) [ 54 , 61 ] reported that increased trace metal conditions (e.g., zinc, cobalt, copper, or selenium) in f/2−Si medium enhanced the iso-DA C production in a New Zealand P. australis strain.…”