Scientists are making headlines with a startling revelation: they've pinpointed a lesser-known algal species, known as Karenia cristata, as the potential source of the toxic brevetoxins found in the troubling algal bloom affecting South Australia. This discovery, which is currently under academic scrutiny, highlights that Karenia cristata was the prevailing species throughout much of the bloom's duration, alongside four other identified Karenia species.
Karenia cristata stands out as the only species among these that is known to produce the hazardous brevetoxins that have raised health concerns.
Leading the research is Professor Shauna Murray from the University of Technology Sydney (UTS), who has spearheaded efforts to track down the species responsible for these toxins. Her team's investigation commenced after alarming reports in March indicated that substantial sea foam, marine life fatalities, and adverse health effects among beachgoers near Victor Harbor were surfacing.
Interestingly, Karenia cristata had not been documented in Australian waters until now; it has only been found previously in two instances off the coast of South Africa and once near Newfoundland, Canada. The study raises the alarming prospect that Karenia cristata could be an emerging global threat, especially in the context of evolving oceanic conditions.
Professor Murray noted that surfers in the Victor Harbor area were exhibiting respiratory issues in March, hinting at the existence of a brevetoxin-producing species beyond the initial suspicion of Karenia mikimotoi. This assumption gained traction in early May when the South Australia Shellfish Quality Program confirmed the detection of brevetoxins in local waters, marking a significant turning point in their research journey.
"At that point, we definitely realized we had to seek out another species of Karenia relating to this bloom," Professor Murray stated, highlighting the urgency of their investigation.
The race to find answers has been intense. Professor Murray remarked that identifying these algal species was a monumental task, yet they achieved remarkable results in what can only be described as a rapid timeframe. Typically, such research can span several years, but this team accomplished their findings in mere months through diligent teamwork and coordination.
Regular samples were collected from 39 different locations, revealing that algal blooms typically comprise multiple species rather than a singular type. "These species often coexist," she explained, indicating that the dominant type can shift over time and vary from one location to another.
A pressing question remains: how did Karenia cristata find its way into Australian waters? Professor Murray pointed to the gap in historical research, which leaves the origins of this species unclear. She speculated that it might have been present all along, as evidenced by the species’ prior detections in such disparate locations as Canada and South Africa.
Describing it as part of the 'hidden flora', she emphasized these are species that may exist but aren't very populous and have often escaped rigorous investigation. Although much remains unknown about Karenia cristata, Professor Murray noted previous blooms in South Africa suggested it thrives in water temperatures between 14 and 18 degrees Celsius. Observational evidence seems to indicate a similar trend in South Australia, with growth rates of this algae appearing to spike during the cooler months starting around May. However, she warned that more comprehensive studies are necessary to understand the environmental conditions favoring this species’ proliferation.
Professor Murray voiced concern over the broader misunderstanding and misrepresentation of the algal bloom since its onset. Identifying the additional species of Karenia is just the first step; there’s still a wealth of research to be undertaken. It's crucial not only for South Australia but for the entire nation to monitor these species, particularly when considering the potential human health implications linked to brevetoxins.
The brevetoxins produced by Karenia cristata share similarities with those generated by Karenia brevis, a species known for its frequent blooms along the coast of Florida in the United States. The noteworthy distinction is that the Australian variant does not produce one particular analogue, named BTX-1, which is commonly found in the US; instead, it creates different chemical forms of brevetoxins.
As far as Professor Murray is aware, there hasn’t been extensive research comparing the toxicity levels of these various chemical forms, but she anticipates that they might exhibit comparable toxicological effects.
This finding could prompt a significant debate: what exactly do we know about algal blooms and their impacts on human and marine life? As the scientific community and the public alike ponder these questions, your thoughts are welcome. Do you agree with the findings related to Karenia cristata, or do you think there could be more factors at play? Let's discuss!
