Presentation Abstract

Preliminary results from a newly funded NOAA NCCOS MERHAB project developing new molecular methods for detecting Alexandrium catenella cyst concentrations in marine sediments will be presented. A. catenella is a dinoflagellate that produces saxitoxin, a powerful neurotoxin, that can be concentrated in filter feeding shellfish which, if ingested by humans, can lead to paralytic shellfish poisoning and potentially death. A. catenella overwinters as a cyst in the sediment and when environmental conditions are right, in the spring and summer, germinates into the water column as a vegetative cell. Previous studies have mapped the winter distribution of A. catenella cysts in Puget Sound sediments as a way of providing shellfish growers with an early warning system of potential hotspots for blooms of this harmful alga (HABs). The standard method for cyst detection in sediments depends on collecting sediment samples in winter, sieving, preserving, and staining the samples and manually enumerating the cysts using epifluorescence microscopy. This method is very labor intensive and requires extensive training to accurately identify the cysts. This new MERHAB project aims to develop new quantitative molecular assays (qPCR and FISH – fluorescent in situ hybridization) that will be compared with the existing standard microscopy protocol using surface sediment samples from Puget Sound, the Gulf of Maine, and Alaska to see if these new molecular techniques represent a viable alternative to the existing standard microscopy method. Preliminary maps of A. catenella surface sediment cyst distribution from winter 2020 in Puget Sound will be presented, as well as initial comparisons of cyst concentrations determined using both the molecular and microscopy methods.

Session Title

Track: Trophic Interactions - Zooplankton, Phytoplankton, Salmon, Forage Fish & Invasive Species – Posters

Conference Track

Trophic Interactions - Zooplankton, Phytoplankton, Salmon, Forage Fish & Invasive Species

Conference Name

Salish Sea Ecosystem Conference (2020 : Online)

Document Type

Event

SSEC Identifier

2020_abstractID_5455

Start Date

21-4-2020 9:00 AM

End Date

22-4-2020 4:45 PM

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Language

English

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Apr 21st, 9:00 AM Apr 22nd, 4:45 PM

Mapping the cysts of Alexandrium catenella in the surface sediments of Puget Sound: A comparison of microscopy and molecular methods for enumeration

Preliminary results from a newly funded NOAA NCCOS MERHAB project developing new molecular methods for detecting Alexandrium catenella cyst concentrations in marine sediments will be presented. A. catenella is a dinoflagellate that produces saxitoxin, a powerful neurotoxin, that can be concentrated in filter feeding shellfish which, if ingested by humans, can lead to paralytic shellfish poisoning and potentially death. A. catenella overwinters as a cyst in the sediment and when environmental conditions are right, in the spring and summer, germinates into the water column as a vegetative cell. Previous studies have mapped the winter distribution of A. catenella cysts in Puget Sound sediments as a way of providing shellfish growers with an early warning system of potential hotspots for blooms of this harmful alga (HABs). The standard method for cyst detection in sediments depends on collecting sediment samples in winter, sieving, preserving, and staining the samples and manually enumerating the cysts using epifluorescence microscopy. This method is very labor intensive and requires extensive training to accurately identify the cysts. This new MERHAB project aims to develop new quantitative molecular assays (qPCR and FISH – fluorescent in situ hybridization) that will be compared with the existing standard microscopy protocol using surface sediment samples from Puget Sound, the Gulf of Maine, and Alaska to see if these new molecular techniques represent a viable alternative to the existing standard microscopy method. Preliminary maps of A. catenella surface sediment cyst distribution from winter 2020 in Puget Sound will be presented, as well as initial comparisons of cyst concentrations determined using both the molecular and microscopy methods.