Moss Landing Marine Labs Assistant Professor Scott Hamilton tends to his research subjects — hundreds of captured, juvenile rockfish he’s studying with a 330,000 National Science Foundation grant to find the impact of carbon dioxide and acidification of seawater on rockfish. (Dan Coyro — Santa Cruz Sentinel)

 

MOSS LANDING >> Scott Hamilton peers into tanks filled with tiny juvenile rockfish, looking for answers.

The oceans are growing more acidic and oxygen levels are dropping, consequences, along with climate change, of carbon emissions.

Hamilton, a researcher at Moss Landing Marine Laboratories, has received a $330,000 National Science Foundation grant to study the impact on the young rockfish.

Will there be significant changes in their swimming ability or respiratory function? Will their neurological operations be impaired? Will some species tolerate the acidity and lowered oxygen levels better than others? Will any be able to adapt? The answers to these questions can help guide policy-makers and fisheries managers in years to come, Hamilton said.

“We want to understand how fish communities are going to change,” he said.

There’s little doubt they’ll change. About half of carbon emissions and other greenhouses gases released into the atmosphere have been absorbed by the ocean, scientists say. That’s slowed the progress of climate change, but during the past decade, scientists have become more aware of the negative impact on marine life from the resulting rise in acidity.

The problem is worsening. Since the start of the Industrial Revolution in the late 18th century, ocean acidity has increased 30 percent, and it’s expected to rise exponentially in coming years. By the end of the century, the National Oceanic and Atmospheric Administration says the surface waters of oceans could be 150 times more acidic.

Hamilton’s grant is part of $11.4 million in recently awarded National Science Foundation funding to study the issue. Hamilton’s research partners at Cal State Monterey Bay and Humboldt State received similar grants for a total of $900,000.

Hamilton’s research will build on a two-year study he and his students are wrapping up in a lab at the nearby Monterey Bay Aquarium Research Institute. The study found blue rockfish were more tolerant of acidic waters than copper rockfish.

The new study will examine additional rockfish species collected from the kelp forests of Carmel Bay for behavioral, physiological and molecular changes.

To complete the work, the fish are tattooed with a fluorescent dye for individual identification and then placed in tanks with seawater collected 60 feet off the Moss Landing shore and made acidic at varying levels based on projections for future conditions. The fish are then run through a series of tests, such as an underwater “treadmill” that uses variable currents to measure swimming speeds and aerobic capacity. In another test, they are placed in a tank infused with the odor of predatory fish and given a choice in direction to evaluate their olfactory keenness.

Humboldt State researchers will conduct the same experiments with fish gathered off the Northern California coast to analyze regional differences.

Afterward, the fish will be dissected and their tissues examined. Scientists from CSUMB and UC Santa Cruz will take the study down to the level of genes.

Rockfish were chosen as experimental subjects because of the diversity of species, their importance to sport and commercial fisheries and the critical role they play in the ecosystem, Hamilton said.

Juveniles, he said, besides being easy to work with due to their small size, provide clues to the future.

“It’s a critical life stage,” Hamilton said. “The survival and success of the juveniles is what’s going to determine the success of the fisheries later.”

Rockfish research

What: A study of the impact of growing ocean acidity on fish populations.

Why: Acidity, caused by carbon emissions, is increasing and is expected to affect marine life and recreational and commercial fisheries.

Where: Studies at Moss Landing Marine Laboratories and Humboldt State.

When: 2014-2017.

Who: Scott Hamilton, Moss Landing Marine Labs and San Jose State; Cheryl Logan, Cal State Monterey Bay; Eric Bjorkstedt and Brian Tissot, Humboldt State; Giacomo Bernardi, UC Santa Cruz; Susan Sogard, National Oceanic and Atmospheric Administration National Marine Fisheries Service in Santa Cruz.

Funding: $900,000 in National Science Foundation grants.

 

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