Harmful algal blooms, often referred to as HABs, emerge when algae proliferate excessively. These photosynthetic organisms primarily inhabit aquatic environments and depend on sunlight for their energy needs. Due to climate change, the occurrence and severity of harmful algal blooms are increasing worldwide. A team of researchers from Hiroshima University has provided new insights into the interactions among algal species and their environmental conditions in coastal regions.
This research was published in Marine Pollution Bulletin on December 15.
“The goal of this study was to explore how harmful algal species interact with other phytoplankton and environmental factors such as temperature and salinity. This understanding is vital, as harmful algal blooms have been rising in Chile, significantly affecting the aquaculture sector, particularly salmon farming, which is crucial for Chile’s economy as it ranks as the world’s second-largest salmon producer,” stated So Fujiyoshi, an assistant professor at Hiroshima University’s The IDEC Institute in Hiroshima, Japan.
The investigation employed a statistical technique known as empirical dynamic modeling to analyze the interactions among different algal species, utilizing long-term data. By examining phytoplankton monitoring information gathered over 28 years, researchers sought to determine whether temperature, salinity, or the presence of other phytoplankton species influenced the proliferation of Pseudo-nitzschia, a prominent algal species group associated with harmful algal blooms. This group is recognized for producing a neurotoxin called domoic acid, which contaminates shellfish and fish and can lead to a rare illness known as amnesic shellfish poisoning (ASP) when ingested. Symptoms of ASP include vomiting, nausea, diarrhea, headaches, confusion, short-term memory loss, seizures, and, in rare instances, even fatalities.
“Our research revealed that Pseudo-nitzschia interacts in complex ways with other algal species. We also discovered that salinity could play a more critical role than temperature, which was previously viewed as a major factor. This finding may enhance our capacity to anticipate harmful algal blooms,” Fujiyoshi remarked.
The researchers pointed out that the empirical dynamic modeling approach is merely the initial step in comprehending the interactions between Pseudo-nitzschia and other algal groups. The subsequent phase will involve practical ecological observations.
Looking to the future, the research team aims to apply their findings to develop a biological model for predicting harmful algal blooms. “Next steps will encompass incorporating additional environmental variables, especially nutrient fluctuations due to upwelling, examining the specific mechanisms through which different phytoplankton species affect Pseudo-nitzschia, and turning these discoveries into a useful prediction model that could safeguard the aquaculture industry,” Fujiyoshi added.
Other contributors to this research include Ishara Uhanie Perera from Yamaguchi University; Daiki Kumakura and Shinji Nakaoka from Hokkaido University; Carolina Medel, Oscar Espinoza-González, and Leonardo Guzmán from Instituto de Fomento Pesquero; Kyoko Yarimizu, Fumito Maruyama, Milko A. Jorquera, and Hansoo Lee from Hiroshima University; Felipe Tucca and Alexander Jaramillo-Torres from Instituto Tecnológico del Salmón; Yukako Tohsato from Ritsumeikan University; and Jacquelinne J. Acuña from Universidad de la Frontera.
This research was supported by the Science and Technology Research Partnership for Sustainable Development, JSPS KAKENHI Fostering Joint International Research, and the JSPS Bilateral Program.
