Details:

Journal Title:
Harmful Algae
Personal Author:
Kramer, Benjamin J. ; Hem, Ronojoy ; Gobler, Christopher J.
Kramer, Benjamin J. ; Hem, Ronojoy ; Gobler, Christopher J. Less -
NOAA Program & Office:
NOS (National Ocean Service)
Description:
The effect of rising CO2 levels on cyanobacterial harmful algal blooms (CHABs) is an emerging concern, particularly within eutrophic ecosystems. While elevated pCO2 has been associated with enhanced growth rates of some cyanobacteria, few studies have explored the effect of CO2 and nitrogen availability on diazotrophic (N2-fixing) cyanobacteria that produce cyanotoxins. Here, the effects of elevated CO2 and fixed nitrogen (NO3−) availability on the growth rates, toxin production, and N2 fixation of microcystin, saxitoxin, and anatoxin-a - producing strains of the genus Dolichospermum were quantified. Growth rates of all Dolichospermum spp. were significantly increased by CO2 or both CO2 and NO3− with rates being highest in treatments with the highest levels of CO2 and NO3−for all strains. While NO3− suppressed N2 fixation, diazotrophy significantly increased when NO3−-enriched Dolichospermum spp. were supplied with higher CO2 compared to cultures grown under lower CO2 levels. This suggests that diazotrophy will play an increasingly important role in N cycling in CO2-enriched, eutrophic lentic systems. NO3− significantly increased quotas of the N-rich cyanotoxins, microcystin and saxitoxin, at ambient and enriched CO2 levels, respectively. In contrast, elevated CO2 significantly decreased cell quotas of microcystin and saxitoxin, but significantly increased cell quotas of the N-poor cyanotoxin, anatoxin. N2 fixation was significantly negatively and positively correlated with quotas of N-rich and N-poor cyanotoxins, respectively. Findings suggest cellular quotas of N-rich toxins (microcystin and saxitoxin) may be significantly reduced, or cellular quotas of N-poor toxins (anatoxin) may be significantly enhanced, under elevated CO2 conditions during diazotrophic cyanobacterial blooms. Finally, in the future, ecosystems that experience combinations of excessive N loading and CO2 enrichment may become more prone to toxic blooms of Dolichospermum.
Keywords:
[+]
Aquatic Science Plant Science
Source:
Harmful Algae, 120, 102354
DOI:
https://doi.org/10.1016/j.hal.2022.102354
ISSN:
1568-9883
Format:
PDF
Publisher:
Elsevier BV
Document Type:
Journal Article
Funding:
Grant no. NA19NOS4780186
License:
https://creativecommons.org/licenses/by-nc-nd/4.0/
Rights Information:
CC BY-NC-ND
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:2fa0a7d91c138a528aa1e3b2f0cc80b95e5cd6d0dcc16a0b415263daba132fb7
Download URL:
https://repository.library.noaa.gov/view/noaa/59455/noaa_59455_DS1.pdf
File Type:

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