Sub-tropical benthic/epiphytic dinoflagellates of Aotearoa New Zealand and Rangitāhua Kermadec Islands

Lesley L Rhodes; Kirsty F Smith; J Sam Murray; Emillie M F Passfield; Roberta D'Archino; Wendy Nelson; Tomohiro Nishimura; Lucy Thompson; Tom Trnski

doi:10.1016/j.hal.2023.102494

Sub-tropical benthic/epiphytic dinoflagellates of Aotearoa New Zealand and Rangitāhua Kermadec Islands

Harmful Algae. 2023 Oct:128:102494. doi: 10.1016/j.hal.2023.102494. Epub 2023 Sep 4.

Authors

Lesley L Rhodes¹, Kirsty F Smith², J Sam Murray², Emillie M F Passfield², Roberta D'Archino³, Wendy Nelson⁴, Tomohiro Nishimura⁵, Lucy Thompson², Tom Trnski⁶

Affiliations

¹ Cawthron Institute, 98 Halifax St East, PB 2, The Wood, Nelson 7010, New Zealand. Electronic address: Lesley.rhodes@cawthron.org.nz.
² Cawthron Institute, 98 Halifax St East, PB 2, The Wood, Nelson 7010, New Zealand.
³ National Institute of Water and Atmospheric Research Ltd, PB 14-901, Wellington 6241, New Zealand.
⁴ National Institute of Water and Atmospheric Research Ltd, PB 14-901, Wellington 6241, New Zealand; School of Biological Sciences, University of Auckland, Auckland 1014, New Zealand.
⁵ Cawthron Institute, 98 Halifax St East, PB 2, The Wood, Nelson 7010, New Zealand; Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture and Marine Science, Kochi University, 200 Otsu, Monobe, Nankoku, Kochi 783-8502, Japan.
⁶ Auckland War Memorial Museum, PB 92018, Victoria Street West, Auckland 1010, New Zealand.

PMID: 37714580
DOI: 10.1016/j.hal.2023.102494

Abstract

Temperatures and temperature anomalies have been increasing in the sub-tropical regions of Aotearoa New Zealand and these changes may impact on harmful algal bloom (HAB) events. Benthic and epiphytic dinoflagellates, particularly the toxin producers, are the focus of this study as it is predicted that under future climate conditions they may produce more toxins or marine animals may become more susceptible to them. The results of past expeditions to Rangitāhua Kermadec Islands and sampling trips to Northland, Aotearoa New Zealand, are summarised and the results of the most recent trips to both regions are presented. The macroalgal habitats of the dinoflagellates are also characterised. Dinoflagellate species not previously identified in Rangitāhua include Coolia canariensis, C. palmyrensis, and C. tropicalis, all identified by DNA sequencing of the large subunit ribosomal RNA region. Gambierdiscus polynesiensis was again isolated and produced 44-methylgambierone and gambierone, and one isolate produced ciguatoxins, the cause of Ciguatera Poisoning. An Ostreopsis tairoto isolate, as analysed by the oxidative cleavage method, produced a palytoxin (PLTX)-like amine oxidation fragment, but when analysed for PLTX-like analogues using a new intact method none were detected indicating an 'unknown' PLTX-like compound is produced by this isolate. Isolates of O. cf. siamensis (Ostreopsis sp. 9), collected in Northland, were also analysed using the oxidative cleavage method, with the common PLTX-like amine fragment and the amide fragment corresponding to bishomoPLTX detected in all isolates. Again, the intact method indicated no detections in the isolates, again suggesting an unknown compound was being produced by these isolates. Prorocentrum hoffmannianum isolates produced okadaic acid (OA) and isoDTX-1 and P. lima isolates produced OA, DTX-1, and isoDTX-1. It is expected that new species of potentially harmful, benthic dinoflagellates will continue to be recorded in Aotearoa New Zealand and the results from Rangitāhua provide a guide to the HAB species to expect in sub-tropical Northland as the oceans continue to warm.

Keywords: Aotearoa New Zealand; Biotoxins; Epiphytic/benthic dinoflagellates; High-throughput sequencing metabarcoding; Rangitāhua Kermadec Islands.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amines
Animals
Dinoflagellida*
Harmful Algal Bloom
Islands
New Zealand

Substances

palytoxin
Amines