Death in the tide pools: Rapid die-off of urchins and sea stars a grim warning of climate change

By Kat Kerlin

In August 2011, scientists at the UC Davis Bodega Marine Laboratory walked into their labs to a strange, disturbing sight: Thousands of purple sea urchins and other marine invertebrates were dead in their tanks, which are fed directly by seawater. Outside, the tea-colored ocean washed up carcasses of red abalone, large sea stars, and football-sized, snail-like chitons.

Less conspicuous—but even more heavily impacted as a population—were the millions of purple sea urchins and tiny sea stars that died along a 62-mile stretch of coast in Northern California, according to a UC Davis-led study published in the journal PLOS ONE that documents the die-off.

“We might not have known urchins and six-armed sea stars were affected if lab-held animals hadn’t died right in front of us,” said the study’s lead author Laura Jurgens, a graduate student at UC Davis Bodega Marine Laboratory who earned her doctorate in May.

Long-term consequences

The scientists documented almost 100 percent mortality of purple sea urchins and six-armed sea stars over the study area, which stretched from southern Mendocino County to Bodega Bay in Sonoma County. Intertidal zones that once looked like pools of purple held only burrows in the bedrock—telltale markers that purple sea urchins were once there. Only 10 purple urchins were found in an area once home to millions of them.

Tidepools before (left) and after (right) the 2011 die off. Only burrows in the rock remained. Laura Jurgens/UC Davis Bodega Marine Laboratory

Tidepools before (left) and after (right) the 2011 die off. Only burrows in the rock remained. Laura Jurgens/UC Davis Bodega Marine Laboratory

The disappearance of these species to the area suggests long-term population and ecosystem consequences, the study said.

“We’re expecting real ecological changes in how these tide pools operate,” Jurgens said.

The silver-dollar-sized, six-armed sea star is a key tide-pool predator, and purple sea urchins serve as cleanup crews and recyclers for kelp detritus that washes ashore, processing the kelp into nutrients. Purple sea urchins also provide food for shorebirds and some mammals living along the coast.

 Algal bloom likely culprit

Unlike sea star wasting syndrome, a disease that has progressed over years as sea stars literally waste away, this die-off was fast, wiping out these two species in as little as a few days. The die-off also occurred about two years before recent incidences of sea star wasting syndrome were observed along the West Coast.

Six-armed sea stars like this one experienced almost 100 percent mortality across a 62-mile stretch of coast in Northern California in 2011. Credit: Laura Jurgens/UC Davis Bodega Marine Laboratory

Six-armed sea stars like this one experienced almost 100 percent mortality across a 62-mile stretch of coast in Northern California in 2011. Credit: Laura Jurgens/UC Davis Bodega Marine Laboratory

Instead, the study said the mass mortality was likely caused by a harmful algal bloom. Such blooms are expected to occur more often due to the combination of global warming, ocean acidification, and land-use changes.

Jurgens said that is all the more reason why documenting such mass mortality events is important to better understand — and prepare for –trends happening to ocean ecosystems.

‘We might forget’

Purple sea urchins have begun to recolonize the area. But it might be decades before the more home-bodied six-armed sea stars return to the area, since their babies can only crawl small distances away from their mothers. Males and females would need to arrive on floating debris to begin to repopulate the species here, which Jurgens said is unlikely to happen very often.

“If someone were to come to this area, they wouldn’t know these six-armed sea stars existed here, even though this has been a main part of their species range,” Jurgens said. “If something disappears and we don’t document it, we might not ever know it was there, and we might forget.”

Study support

The study was primarily funded by the National Science Foundation. It also received financial support from the Monitoring Enterprise, California Ocean Sciences Trust, Partnership for Interdisciplinary Studies of Coastal Oceans, the David and Lucile Packard Foundation and the California Department of Fish and Wildlife.

Co-authors from UC Davis Bodega Marine Laboratory and the UC Davis Coastal Marine Sciences Institute include evolution and ecology professors Brian Gaylord and Rick Grosberg, as well as Laura Rogers-Bennett from BML, UC Davis Wildlife Health Center, and the California Department of Fish and Wildlife. Other co-authors include UC Santa Cruz professor Peter Raimondi, and graduate student Lauren Schiebelhut and associate professor Michael Dawson from UC Merced.

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15 responses to “Death in the tide pools: Rapid die-off of urchins and sea stars a grim warning of climate change

  1. So they withheld this information for four years, despite the mass die-offs? These scientists should be charged with crimes against humanity for lying about this. Withholding information is lying, especially when it involves all life on this planet. How f-ing arrogant those scientists are, not sharing the info with the public lest it offend their masters. They sold their souls for a mortgage and an SUV.

    Who tested the radiation levels of the seawater? It doesn’t take a PhD to logically assume that the three melt outs in Japan have contaminated the ground, air and water (200,000 tons of radioactive water dumped into the ocean daily for 4 1/2 years) and that is the reason for these unprecedented die-offs. They all occurred post 3/11. Coincidence? Who in their right mind wouldn’t test for radiation, as it is the most likely source. Uranium isotopes from Fukushima were found in Hawaii within a week, and in heavy concentrations. That, of course, has been scrubbed by the EPA, but the cached reports are still online. Within three weeks of 3/11, strawberries, kelp, milk, arugula and spinach in California tested positive for Fukushima radiation. Currently, they are still finding radioactive Iodine with a half life of eight days, which means the fission process has never ended.

    It is not a virus. When a virus juts, it loses strength. Furthermore, viruses don’t have 100 percent kill ratios on every species or it would not have a host. Domoic acid becomes unstable in water after two days. No baby whale calf in the North Pacific has survived more than a year post 3/11. The washed up animals have lesions, bleeding and hemorrhaging and other indications of radiation poisoning.

    Why is everyone afraid to admit the F word, Fukushima?

  2. And this has nothing to do with climate change! These organisms have survived hundreds of millions of years of ocean temperature, salinity, and acidification changes.

    But if you care about climate change, then call up the officials at HAARP and tell them to stop manipulating the weather. Look up at the skies and you will see the weather modification program right in front of you. Those are not contrails. Contrails disappear after a few minutes. These turn into metallic clouds that inhibit rain from passing storms.

  3. Kelly,
    Thank you so much for your input. SO well said. every bit of it the truth. We have let a Genie out of a bottle, that no one in mankind knows how to clean up after. It is so bizarre how “scientists” can choose to overlook something as serious as radiation, when its tangible, measurable, and most of the public continues to eat sushi. You mention the possibility of radioactive contamination of ocean fish, and they look at you like you are wearing a tin foil hat. It’s the other way around, nearly everyone is in denial. A real life episode of the Twilight Zone. Hey scientists out there, can we try scientific method!

  4. I doubt this is Fukushima related – the proportion of micron-sized Chemtrail material being dumped is far far greater than however many rods are in Fukushima. Also, there are a lot of HAARP/EMR things going on in the ocean with the military. Remember than ocean creatures breathe too – and all this HAARP/Chemtrail stuff is heating waters and causing a massive amount of cardiovascular disease and strokes to land animals and humans, so … just do a search for example on Alaska Fish Hatchery … and see how they are trying to keep the illusion of fish alive, when they are naturally extinct. Search your weather/temperature history records – you will see …

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  6. This is not chemtrails or algea or from a temp change. The fact is the temp aroung the world has changed up and down throughtout the years. It changes every season. This is the mixture of everything we have been dumping into the ocean and now on too of that we ha e fukushima. The jet syream and the oceans currents move from west to east and that is why we are seeing the dieoffs on a mass scale never seen before. Fukushima is uncharted territory. It has never happened before nor have they even so much as made attemps to ask the qurstion what if this happens. Which means now there is not one single definative person that can be the expert and know what will happen. No experts and even the experts dont want to touch it. No make no mistake this is due to fukushima

  7. People!! Maybe it would be fukishima, or other chemicals, BUT it’s always only one or 2 specific species at a time and it’s happening all around the world including birds! Mass die offs happening everywhere!! Birds literally falling out of sky to their deaths!!! Scientists say it’s a mystery but they think it’ could have been fire works! It affected 1 species at a time, and who would believe fireworks!!?? Why hasn’t it ever happens before, and what about all the other birds?
    It’s startling when u see 15 pilot whales dead on shore, and birds dying, tons and tons of sea life in staggering proportions! Google has created a map for all the mass animal deaths!!

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