Abstract Title

Session S-08A: Harmful Algal Blooms, Climate, Shellfish, and Public Health - Emerging Issues in a Changing World

Proposed Abstract Title

Environmental Controls on the Growth and Toxicity of Alexandrium Catenella from Puget Sound

Presenter/Author Information

Brian BillFollow

Keywords

Harmful Algal Blooms and Shellfish

Location

Room 6C

Start Date

1-5-2014 5:00 PM

End Date

1-5-2014 6:30 PM

Description

The dinoflagellate Alexandrium catenella produces a suite of potent neurotoxins that can cause the potentially fatal illness paralytic shellfish poisoning in humans who consume contaminated shellfish. Specific growth rates and toxicity of A. catenella were examined here in relation to two environmental factors; temperature and salinity. Two strains of A. catenella were isolated from Puget Sound; NWFSC 439 from the north in Guemes Channel and NWFSC 445 from the south in Quartermaster Harbor. After acclimating to the experimental conditions for 2 weeks, growth was recorded daily using a fluorometer at 19 temperatures ranging from 5-28°C and 6 salinities ranging from 10-35 psu. The maximum specific growth rate was 0.55 µ d-1 with optimal growth (i.e., >0.20 µ d-1) observed for temperatures between 8.9-25.5°C and salinities between 15-35 psu. No significant growth was observed at temperatures below 7.7°C or at 10 psu. Cellular toxicity ranged from 0.2 to 109.9 pg saxitoxin cell-1, with the highest toxicity occurring for environmental conditions that promoted slower growth. This may indicate an accumulation of toxin within the fewer numbers of cells growing at the lower temperatures. Experimental results were used to create a growth response surface for A. catenella in Puget Sound as a function of temperature and salinity. Modeling efforts combine this growth response with data on cyst distributions and germination rates (see presentation at this conference by C.L. Greengrove) to map favorable habitat for A. catenella in Puget Sound, both for the present-day and in a future Puget Sound influenced by climate change (see presentation at this conference by S.K. Moore). Modeling results suggest that future environmental conditions in Puget Sound may promote a longer bloom season for A. catenella, rather than increasing the growth rate.

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May 1st, 5:00 PM May 1st, 6:30 PM

Environmental Controls on the Growth and Toxicity of Alexandrium Catenella from Puget Sound

Room 6C

The dinoflagellate Alexandrium catenella produces a suite of potent neurotoxins that can cause the potentially fatal illness paralytic shellfish poisoning in humans who consume contaminated shellfish. Specific growth rates and toxicity of A. catenella were examined here in relation to two environmental factors; temperature and salinity. Two strains of A. catenella were isolated from Puget Sound; NWFSC 439 from the north in Guemes Channel and NWFSC 445 from the south in Quartermaster Harbor. After acclimating to the experimental conditions for 2 weeks, growth was recorded daily using a fluorometer at 19 temperatures ranging from 5-28°C and 6 salinities ranging from 10-35 psu. The maximum specific growth rate was 0.55 µ d-1 with optimal growth (i.e., >0.20 µ d-1) observed for temperatures between 8.9-25.5°C and salinities between 15-35 psu. No significant growth was observed at temperatures below 7.7°C or at 10 psu. Cellular toxicity ranged from 0.2 to 109.9 pg saxitoxin cell-1, with the highest toxicity occurring for environmental conditions that promoted slower growth. This may indicate an accumulation of toxin within the fewer numbers of cells growing at the lower temperatures. Experimental results were used to create a growth response surface for A. catenella in Puget Sound as a function of temperature and salinity. Modeling efforts combine this growth response with data on cyst distributions and germination rates (see presentation at this conference by C.L. Greengrove) to map favorable habitat for A. catenella in Puget Sound, both for the present-day and in a future Puget Sound influenced by climate change (see presentation at this conference by S.K. Moore). Modeling results suggest that future environmental conditions in Puget Sound may promote a longer bloom season for A. catenella, rather than increasing the growth rate.