Young Voices

Traveling Around the World to Study the Future of the Ocean

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It takes three days of traveling to reach the islands of Papua New Guinea (PNG) from the Smithsonian’s National Museum of Natural History in Washington, D.C. Laetitia Plaisance, a researcher at the Museum, has made the trip three times. After five planes, she goes on a 12-hour boat ride to a small island inhabited by a few thousand people where she spends 21 days working 15 to 17 hours each day on a boat processing samples. 

But why does she do all this? She and other Smithsonian scientists, in collaboration with scientists from the Australian Institute of Marine Science, along with the help of interns and volunteers, are working on a project that will give us a glimpse into the future of coral reefs, which are being affected by ocean acidification

Ocean acidification is the decrease in the ocean’s pH level, making the water more acidic. Carbon dioxide (CO2) and other greenhouse gasses are emitted into the atmosphere by humans driving cars and producing electricity with coal, oil and natural gas. The ocean has absorbed one-third of these excess CO2 emissions. Over the past 200 years oceans have become 30 percent more acidic; this is the fastest recorded change of the ocean's chemistry over the past 50 million years. These changes impact many ecosystems, including coral reefs and the animals that rely on them. Most corals struggle to build their calcium-carbonate structures in a more acidic environment, and so do other shelled organisms (like snails). 

The first step in the study began in 2012 when the ARMS, or Autonomous Reef Monitoring Structures, were deployed. These plastic structures mimic small crevices of coral reefs and allow small organisms to live there. The ARMS were deployed on the small island they travel to for two main reasons. The first is the great variety and diversity of species found there, even some that have yet to be discovered and named by scientists. The second is the village Ili Ili Bua Bua (it means “water water bubble bubble” in the local language), which sits next to reefs that have naturally occurring volcanic seeps of carbon dioxide, causing the water to be more acidic than normal ocean water.

Tiny organisms found on ARMS
A diversity of organisms are found in ARMS. (Sarah Leinbach, Smithsonian)

By placing the ARMS and observing which organisms colonized the structures at both normal waters and waters with low pH near CO2 seeps, scientists can compare the diversity of the community and the genetic diversity of organisms living in coral reefs in different pH levels. Biodiversity can be assessed at different scales: the morphological diversity as seen by the naked eye or under the microscope and the genetic diversity that can tell apart twin species that look very much alike but that have differences in their DNA. 

After the scientists collect the samples in PNG they are moved to a lab in Washington, D.C. where the analysis can begin. The data from this project will be used to identify and compare invertebrates collected in both coral reef environments: normal and naturally acidified. The results will show which specific animals are being affected by ocean acidification—by just looking at the animals through a microscope you can see a clear decrease in diversity of animals living in low pH waters as compared to the diversity of those living in normal pH levels. This is the work I conducted as a YES! Intern at the National Museum of Natural History in the summer of 2017. 

Even though these organisms are very tiny—some smaller than a grain of rice—they are an important component of the whole ecosystem. When ocean acidification negatively impacts small invertebrates, the animals further up the food chain are also affected, including people--especially those who rely heavily on fish as their main food source. The data will help scientists further understand all the consequences of ocean acidification and predict the effects that ocean acidification will have on coral reef ecosystems. 

October 2017