THE LATEST: Marine Biologist Maggie Johnson Weighs in on Coral & Climate Change

We got to speak with second year PhD student Maggie Johnson, who works with Dr. Jennifer Smith at the Smith Lab at Scripps Institution of Oceanography. She started studying marine biology at James Cook University in Townsville, Australia, where she first encountered the Great Barrier Reef.

Her primary areas of study involve the effects of climate change on coral reef systems. She is currently conducting research on how CO2 pollution affects the physiology and ecology of coral reef seaweeds.

To learn more about Maggie’s research, read here. Check out Maggie’s photos from the Palmyra reef.

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Name: Maggie Johnson

Profession: Marine Biologist

Favorite Coral Type: Fungia, solitary coral that can MOVE! It can flip itself over and even travel (very slowly…)

Aversion to Sushi?: Yes, as much as I love studying seaweeds… I can not stomach eating them! On top of that, it is important to eat sustainably harvested sushi. The Monterey Bay Aquarium produces cards to help people know what species are sustainable.

As a child, I wanted To Be A: An Astronaut

World’s Best Dive Spot: Palmyra Atoll

Have You Ever Been to the GBR?:  Yes! I went to the GBR when I was a Junior at Colby College

What does your research entail? What are you finding about climate change in relation to coral reefs?

My research involves traveling to remote islands in the central Pacific to study global change effects on coral reef algae.  I am interested in learning how CO2 pollution (ocean acidification) effects the ability of algae to grow, calcify, and photosynthesize.

Remote and uninhabited islands provide a unique opportunity to study the effects of global change on coral reefs in the absence of point source local stressors such as overfishing and nutrient pollution.  I am finding that ocean acidification has a negative effect on calcified algae, such as CCA and the green alga Halimeda, and has positive effects on fleshy macroalgae.  In previous work, I found that the combination of ocean acidification and warming temperatures decreased the rates of calcification of CCA in Hawaii.

Decreased calcification rates has important implications for overall reef health, because CCA are an important reef builder and produce settlement cues for coral larvae.  If calcification is reduced in the coming years, this may have repercussions for coral reef stability and the growth and development of corals. Coral reefs have many important ecosystems services to human populations, including acting as a natural barrier to storm surge and wave energy.  If calcified algae and corals on reefs are not able to calcify, and instead are more likely to dissolve, this may influence the ability of coral reefs to act as protection against storms and waves.  In turn, this could results in extensive damage to coastal properties.

How are coral reefs being affected by warmer waters?

Warmer waters increase the incidence of coral bleaching, which is happens when coral expel their symbiotic zooxanthellae. Coral bleaching events are increasing in both frequency and severity with warming ocean temperatures, along with massive coral death.  Corals are the critical framework builder and ecosystem engineer for coral reefs, and warming temperatures and ocean acidification have drastic negative effects on corals.

What is causing the water temperature to increase? Do we have a great hand in this?

Anthropogenic CO2 pollution is causing the increase in ocean temperatures.  Although the climate change debate seems to be mostly political, the scientific community accepts that CO2 pollution is causing the increase in global temperatures. The IPCC reports (2007) and the representative carbon pathways (Meinshausen et al. 2011) show trends of increasing atmospheric CO2. We know that greenhouse gases get trapped in the atmosphere, and result in increases to climate and ocean temperatures.  We also know that CO2 emissions have increased steadily and drastically since the Industrial Revolution.

Long-term data sets from the Mauna Loa observatory, the Hawaii Ocean Time Series (HOTS) and the Bermuda Atlantic Time Series (BATS), without question show increases in atmospheric CO2, increases in ocean CO2, decreases in ocean pH, and increases in ocean temperature.

How detrimental is ground pollution to the ocean’s reefs?

I know less about the effects of ground pollution on coral reefs. I do know that nutrient pollution (eutrophication) can drastically change coastal ecosystems by essentially fertilizing coral reef algae.  In ambient conditions some algae are nutrient limited, and the increase in nutrients from runoff and sewage outfall can release some species from limitation and allow them to thrive. This can be especially problematic when one species is able to out compete and overgrow others, thereby creating a much less diverse and healthy ecosystem.

How important is it that reefs survive? What is their overall place in the ocean’s vast ecosystem?

Coral reefs are an incredibly important ecosystem, not only for their cultural value and aesthetic beauty, but also for the ecosystem services they provide.  Coral reefs provide protection of coastal communities and land from wave and storm damage, they nurture and support fish population that provide an essential source of protein to island and coastal nations, and they contain a large proportion of the ocean’s biodiversity.  Coral reefs are essentially akin to rain forests, and it is extremely troubling that they are threatened by human activities such as pollution and over-fishing.

Do you foresee national or international policy reinstating stricter laws on pollution?

Yes. I think that national and international policy controlling pollution are inevitable.  The evidence is mounting that pollution is harmful to all ecosystems and to human populations. It is only a matter of time before this is more accepted and people are able to convince their politicians to take action.

Already steps are being take to protect coral reefs. Some coral species are even protected under the endangered species act. I am hopeful that policy will be enacted to control and mitigate CO2 pollution.

What would you suggest that every day people do to help save the world’s reefs?

Everyday people can make an effort to reduce their carbon footprint and reduce waste production.  Use green products, energy efficient light bulbs for example.  Travel to school or work using bicycles or carpooling.  It is only by changing every day practices that collectively we can make a difference. If every person makes some small changes, this adds up.  Hopefully we can make these changes in time to save our reefs!


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