Rising temperatures, melting ice, and increased carbon dioxide in the atmosphere caused by climate change all have great effects on the ocean and its inhabitants. Even slight changes in ocean conditions can have a massive impact on oceanic ecosystems, from changing migration patterns to the possible extinction of many species. Even plant life, including toxin-producing algae, will be affected by these changes. In recent years, the frequency of toxic algal blooms has increased, possibly due to changing ocean conditions such as warmer waters, higher acidity, altered salinity, or other such changes (Guanyong, 2017).

The Pseudo-nitzschia genus is one of the algae responsible for these toxic blooms. Twenty six species of Pseudo-nitzschia can produce the toxin domoic acid (Lewis, 2018). This neurotoxin causes digestion issues in minor cases, and neurological issues such as memory loss, seizures, coma, and death when extremely high concentrations are consumed. There is no antidote or treatment for amnesic shellfish poisoning (Washington State Department of Health). Filter feeders such as shellfish store high concentrations of this toxin in their tissues, which can be passed on to humans and marine life when they consume this shellfish (Thessen, 2008). Pseudo-nitzschia does not always produce domoic acid, and a toxic bloom is caused when some change in ocean conditions allows Pseudo-nitzschia to grow in large numbers and prompts the algae to begin synthesising domoic acid. Further understanding of pseudo-nitzschia and domoic acid are necessary to determine what causes algae to produce toxins, and how to predict and prevent toxic blooms. Research on optimal growing conditions of Pseudo-nitzschia and the most efficient method to grow it using mass manufactured materials, such as the Brite-Box photobioreactor, also being done, as large amounts of domoic acid are necessary for the study of the toxin (Lewis, 2018).

Until recently, not much has been known about the production of domoic acid by Pseudo-nitzschia. In September 2018, a study was published in Science Magazine detailing the molecular basis for biosynthesis of domoic acid (Brunson, 2018). This new discovery provides information on the cellular pathways involved in Pseudo-nitzschia’s production of domoic acid, but not what causes blooms to become toxic.

Several studies have been done on the correlation between ocean conditions and toxicity and growth of pseudo-nitzschia, but no strong, consistent correlation has been found. A study of Pseudo-nitzschia was completed in the Chesapeake Bay by collecting samples at different times of year and recording the salinity and temperature of the water. This study found a correlation between salinity, temperature, and amount of Pseudo-nitzschia present in each sample, but no correlation between ocean conditions and domoic acid production (Thessen, 2008). Because this study used samples collected from the ocean, the domoic acid production could have been controlled by a different ocean condition not included in the study, such as acidity or nutrient presence.

Another study sought to clarify unclear and contradicting results received by other studies on the effect of pH on algae by completing the study in a more controlled environment. This study used samples of Akashiwo sanguinea collected from the East China Sea and grown in tanks with controlled pH. This study found that algae grown in lower pH had the greatest growth rate (Guanyong, 2017). This study researched different algae and did not look into the toxicity of the algae but it suggests that pH has a significant effect on algae and prompts further research on the subject.