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National Analytical Response to Harmful Algal Bloom–Related Marine Animal Mortality Events

This project began in January 2000 and is Ongoing

We use extreme events to research new or changing impacts of harmful algal blooms in coastal waters. The NOAA Analytical Response Team leverages cutting-edge analytical methods and collaborative relationships with wildlife biologists to document the impacts of harmful algal blooms on coastal ecosystems. Also, we assist coastal managers and the scientific community in their investigations of harmful algal bloom–related marine animal mortality events.

Why We Care
Science considers many organisms in our coastal waters as “marine sentinel species” acting as a barometer of ocean health and ultimately indicating possible threats to human health. Research from recent decades has proven marine animal die-offs are related to toxic harmful algal bloom (HAB) events. Because HABs are episodic events, the presence of HAB toxins in a given region often show up only when a catastrophic toxic event takes place. For example, a massive die-off of sea lions in California in 1998 was the first evidence that HAB toxins have extensive impacts to marine animals in that region.

Prior to the formal establishment of the NOAA Analytical Response Team (ART), little support existed for investigations and analysis of suspected HAB-related die-offs, and data on the role of HABs in marine animal mortality events was sparse and inconsistent.

What We Are Doing
ART maintains communication with a network of “early event listeners” such as scientists, coastal managers, volunteers and other stakeholders in order to be appraised of HAB-related events as they occur. This "eyes and ears" framework, consisting of our expert scientists from a wide variety of fields, including algal taxonomy, marine genomics (study of all DNA within a cell), toxicology, wildlife ecology, oceanography and chemistry, allows ART to respond to each mortality event with an event-specific solution. We often advise the network on which samples and data are most important to collect for toxin analyses, and we work closely with them on their own investigations into determining the causes of a particular mortality event.

After receiving samples from dead or dying marine animals collected by biologists in the field we use a two-step approach to analysis:

      1. We screen samples using fast, toxin-specific detection methods and then confirm the presence of individual toxins using sophisticated analytical instruments.
      2. We provide a brief but detailed report of our findings to our collaborators for knowledge of possible HAB contributors to the mortality investigation.

Ultimately, our extended efforts in responding to these isolated events help us better understand long-term trends in HAB impact across seasons, years, and geographical regions. Through publishing our most interesting findings in peer-reviewed scientific literature, we assist the general scientific community in understanding the effects of HABs on marine animals throughout the entire US coast as well as internationally.

Benefits of Our Work
Since the creation of ART we have responded to a large number of events related or suspected to be related to toxin-producing HABs. Many have occurred along Florida’s Gulf coast, involving massive die-offs of bottlenose dolphins, manatees, seabirds and finfish. Our work in this region has shown that exposure to brevetoxin, a neurotoxin naturally produced by a species of marine alga known as Karenia brevis, has caused many of these mortality events. We have shown that brevetoxins and another HAB toxin known as domoic acid (produced by the marine algae in the genus Pseudo-nitzschia) frequently contaminate the coastal food web, and can frequently be detected in both live and dead animals.

      • We documented the presence of high levels of domoic acid in California waters during various mortality events.
      • We confirmed the presence of saxitoxin in the stomachs of several endangered fish along the coast of New England and detected domoic acid associated with a humpback whale die-off.
      • In Texas waters we identified toxic acids in deceased dolphins and reported the first occurrence of okadaic acid in marine mammals anywhere.
      • Routine strandings of marine mammals in the Southeast Atlantic coast helped us discover new trends in HAB distribution in pygmy and dwarf sperm whales.

Next Steps
Our work continues to investigate mortality events suspicious of HAB association. However, our current efforts also include seeking to understand what levels of toxins exist in current ecosystem without HAB presence. We expect this information to explain the “baseline” toxin values in a given region’s animals in order to provide some context to compare toxin values for past or future HABs. We also have begun efforts to understand the impact of HAB toxins on marine animals outside of the U.S., particularly in regions where such data does not exist or in regions where HABs could have large but undocumented impacts.

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