New water tanks help douse Los Gatos community’s wildfire fears

http://www.sandiegouniontribune.com/business/biotech/sd-me-toxic-algae-bloom-ucsd-jcvi-20180927-story.html

When normally harmless algae found off the West Coast make a deadly neurotoxin called domoic acid, casualties rocket up the food chain.

Fish and shellfish accumulate the neurotoxin, sickening those who eat them, including birds, marine mammals, and people. High levels of ingestion lead to amnesic shellfish poisoning, a potentially fatal illness causing seizures and short-term memory loss.

During a particularly intense domoic algal bloom in 2015, a sea lion female was found disoriented in Oceanside Harbor with a prematurely born pup. Mother and pup were taken to SeaWorld San Diego. The mother survived being poisoned; the pup did not.

A team led by scientists at UC San Diego’s Scripps Institution of Oceanography and the J. Craig Venter Institute report discovering the genes that causes domoic acid production. Their discovery may help provide early warning of these harmful blooms of algae in the genus Pseudo-nitzschia.

The study was published Thursday in the journal Science. It can be found at j.mp/domoicacid.

Monitoring for the activated genes could provide early warning of incipient algae blooms, said Frances Gulland, senior scientist at The Marine Mammal Center in Sausalito. In 1998, the center discovered the role of domoic acid in poisoning marine mammals.

“We could monitor water samples for domoic acid production by screening for the genes instead of the actual toxin,” said Gulland, who was not involved in the study. “It might be more sensitive and it might also help anticipate when the toxin is going to get produced.”

These harmful algal blooms, unrelated to the so-called “red tides,” have grown more frequent and extensive over the last two decades, Gulland said.

“The big one in 2015 extended from Baja right up to Alaska,” she said. “The earlier ones, 20 years ago, were just off Monterey Bay. So now every summer, all summer along most of the West Coast, there’ll be some bloom somewhere.”

The work builds on a 2011 study that found limited levels of phosphate and increased levels of carbon dioxide induce domoic acid production. That study was led by David Hutchins of the University of Southern California, also a co-author of the new study.

With that knowledge, the research team examined which genes were turned on during production, said Andrew Allen, a study author with joint appointments at Scripps Institution of Oceanography and the J. Craig Venter Institute. The two institutes contributed their respective expertises in marine biology and genomics to crack the code.

Such a genetic test could be done remotely, such as on a buoy or an underwater rover, Gulland said.

“It offers an opportunity to sample offshore and to get more information about what’s happening away from coastal sampling sites,” she said.

“For example, in San Diego, the main sampling is done from Scripps Pier, and that’s a fantastic long-term data series on algal species. But we know nothing about what’s happening 200 miles offshore.”

The work began five years ago, the brainchild of John K. “Patrick” Brunson, a graduate student and one of the study’s lead authors, Allen said.

It was a daunting challenge, he said, because the genetics of these algae are extremely complex.

“He hadn’t been around long enough to know just how hard the problem is,” Allen said. “I warned him, we need to plan the research because a lot of people have tried to tackle domoic acid and not made a lot of progress.”

But Brunson was temperamentally suited to the task because of his interest in medicine, Allen said. And Allen’s USC colleague, Dave Hutchinson, had recently published research on conditions that cause domoic acid production.

“Dave already done those experiments and you know, published this paper just on the physiology and amount of domoic acid,”Allen said. “He had samples in the freezer, you know, from those experiments.

“Dave and I were talking one day and said, maybe we should sequence those samples. We were kind of thinking it was a needle in the haystack.”

They sent Brunson the sequence data, and he went to work.

“He went away for about a month, and sent me an email that said, we’ve really got to talk about this. I think there’s something here,” Allen said.

“I was skeptical and we sat down and looked at it,” Allen said. “Lo and behold, the kinds of genes that we thought should be activated under domoic acid synthesis conditions were much higher than anything else.”

Other study authors included Shaun McKinnie and Bradley Moore of UCSD.

Study funders included the National Science Foundation, the National Institutes of Health, the Gordon and Betty Moore Foundation, and the U.S. Department of Energy.

Related reading

Southern California’s coast emerges as a toxic algae hot spot

Premature sea lion pup born at SeaWorld to rescued mom has died

SeaWorld caring for sea lion pup born to rescued, sickly mother

Sonoma Coast commercial crab season starts

Deaths of dolphins linked to natural neurotoxin

State mussel bans comes early after toxins found

State issues warning on Channel Islands seafood

Red Tides and Domoic Acid Toxicity

Climatic regulation of the neurotoxin domoic acid

https://phys.org/news/2018-09-killer-whales-world-orcas-threatened.html

Polychlorinated biphenyls (PCBs) are a ghost from the past. These chemicals were produced in immense quantities from the 1930s onwards and were broadly phased out in the 1970s/1980s as environmental concerns grew.

As they were very stable and were unable to conduct an electrical current (and therefore excellent insulators), they were mainly used in the electrical supply industry. These same properties also saw them being used in a whole array of miscellaneous applications including as sealants and additives in construction.

It is this chemical stability that means PCBs stubbornly refuse to degrade in the environment and I have spent the past 25 years studying how these and other contaminants end up accumulating in the Arctic, for instance. However, there are two other properties that make these particular chemicals uniquely problematic, unlike, say, common air pollutants or most heavy metals.

The first is that PCBs are semi-volatile, which means that over time they can evaporate into the atmosphere but then later deposit on surfaces when encountering cooler temperatures or with rainfall or attached to particles. Over decades this continued evaporation and deposition (termed “cycling”) has ensured that they’re smeared around the entire planet. PCBs are just as likely to be found deep in the ocean or in Arctic snow as they are in neighbourhood soils, although the concentrations in soil close to “primary sources” such as cities may be orders of magnitude higher.

The second problem is that PCBs tend to work their way up the food web, accumulating in ever higher concentrations as tiny animals (and their unwanted chemicals) are eaten by small animals, who are eaten by larger animals (who take on those same chemicals), and so on. This process of “biomagnification” is most evident in marine food webs where fatty tissue like blubber (a home for PCBs) is an important feature of animals at the top of the food web such as killer whales.

New diets mean new exposure

So, if the chemicals were largely phased out in the early 1980s, why are they continuing to cause a problem? It’s true that background concentrations have declined over the past 20 years or so, based on measurements of PCBs in the air in animals such as seabirds and even in human breastmilk. But the trend varies from place to place and between different species, and there is evidence that climate change is disturbing the “cycling” of these chemicals, potentially slowing the rate of environmental decline.

Furthermore, complex foodwebs in northern oceans, particularly around Europe and North America (where most PCBs were produced and used) are undergoing subtle alterations. Predators like sharks, large fish or killer whales are changing their diets and exploiting new prey, which in turn alters their exposure to PCBs and other contaminants.

PCBs are here for some time to come

What can be done? Unfortunately, the horse has bolted as such and it would implausible to remove “background levels” of PCBs from the world’s oceans.

The key objective now is to maintain surveillance of these chemicals, whether they be in air, water, soil or animals. In most developed countries, end-of-life action ensures that old industrial materials with PCBs are subject to high temperature incineration (an effective way of ensuring complete destruction). Similarly, grossly contaminated industrial sites or dumps are subject to expensive clean-up and incineration activities.

But, while this is effective and safe at a local level, such measures will account for only a very small fraction of the total PCB inventory, most of which is out in the wild. International efforts by organisations like the UN Environment Programme (UNEP) are ensuring that member states are undertaking “stocktaking” activities, containing old storage or dump sites, and undertaking monitoring programmes. This is particularly important across parts of Asia and key states of the former Soviet Union, where PCB production and use was also high.

The legacy of PCBs will continue to haunt us for some while to come. Scientists estimate that the final resting place or “sink” for PCBs is likely to be organic rich soils across the Northern Hemisphere or even ocean sediments. However, in the meantime, PCBs continue to cycle around the environment and are still present in mother’s milk. Maternal transfer from adult female to calf is the key exposure route for most marine mammals and this chemical stress (supplemented by an array of chemical pollutants other than PCBs), alongside climate change induced stress, is a major concern.

Read more at: https://phys.org/news/2018-09-killer-whales-world-orcas-threatened.html#jCp