NOAA Teacher at Sea
Aboard NOAA Ship Bell M. Shimada
March 13-18, 2015
Mission: Channel Islands Deep-Sea Coral Study
Geographic Area: Channel Islands, California
Date: March 14-15, 2015
Day 2: Saturday 3/14/15
Happy Pi Day everyone! The second day on the ship was productive and incredible. The weather was fantastic throughout the entire day, with hardly any wind and a sheet glass ocean. The stillness of the water made it easy to spot wildlife, and during the day we saw multiple pods of dolphins, sea lions, and a variety of sea birds such as cormorants and brown pelicans.
The beautiful weather also made for smooth conditions to launch the ROV. The ROV took three dives today at different locations and depths each time. Peter and his team picked the locations around the Islands, staying true to spots they had visited in previous years. Part of their research involves looking at the same coral beds over the course of many years and recording what they observe and noting any changes that may have occurred. They are observing how the coral, specifically the species Lophelia pertusa, reacts to changes in pH levels and temperature. This information is important in finding indicators for how our ocean is being affected by warmer temperatures and ocean acidification.
So what exactly is ocean acidification?
As humans, we release carbon dioxide (CO2) into the atmosphere and have been doing so in large quantities since the Industrial Revolution. Carbon dioxide is released during combustion, when we drive our cars, power our houses and factories, use electricity, burn things, cut down trees, etc.
The ocean acts as a sponge and absorbs about 30 percent of the carbon dioxide from the atmosphere. However, as levels of CO2 rise in the atmosphere, so do the levels of CO2 in the ocean. This is not great news for our ocean or the organisms that make their home there. When CO2 mixes with seawater, a chemical reaction occurs that causes the pH of the seawater to lower and become more acidic. This process is called ocean acidification.
Even slight changes in pH levels can have large affects on marine organisms, such as fish and plankton. Ocean acidification also reduces the amounts of calcium carbonate minerals that are needed by shell-building organisms to build their shells and skeletons. The damage to these shell-building organisms, including many types of plankton, oysters, coral, and sea urchins, can have a negative ripple effect throughout the entire ocean food web. An important part of the mission of this trip is to see how ocean acidification is affecting different types of deep-sea coral, such as Lophelia pertusa, that use calcium carbonate minerals to build their skeletons.
The scientists and the MARE team conducted three ROV dives throughout the day. The first dive brought up an outstanding Lophelia sample, and along with it a bizarre deep-sea creature called a basket star. Basket stars are a type of invertebrate that are related to brittle stars. Even though they feed mostly on zooplankton, they have long spindly arms that can reach to over a meter in length. It was astonishing to be able to see this alien looking creature alive and moving!
Day 3: Sunday 3/15/15
After long hours and a late night, the MARE team was able to get the manipulator arm on the ROV up and running, after having technical difficulties with it during the first half of our trip. This was perfect timing for the first ROV dive of the day in the waters between Santa Cruz and Anacapa Islands. The goal of this dive was to find scientist Branwen Williams a type coral known as Acanthogorgia. This coral is incredibly beautiful; tall, fan-like and golden in color.
Bombs Away: Branwen hoped to collect samples of this coral to take back to her lab for testing. She and her team of students and scientists will use these samples to ascertain how old the corals are, how fast they grow and what are they eating. Branwen explained to me that coral, similar to trees, have growth rings that can be used to determine age as well as other factors. She mentioned that when looking at age, she looks for the pattern of the “bomb curve” within the coral rings and that provides scientists with a relative date of how old the corals are. The “bomb curve” is a concentration of radiocarbon (14C) that is found in corals in every ocean in the world. The concentration of radiocarbon is a direct product of the bomb testing that took place starting in the 1950’s and produced large amounts of this radiocarbon into the atmosphere. The ocean absorbed that particular type of carbon, and in turn it was absorbed by the corals, who are suspension feeders. Suspension feeding means that corals eat by stretching their tentacles out to catch tiny particles that are floating by. So scientists identify the start and peak of the bomb testing in the radiocarbon stored in the coral skeleton to determine growth rates and then the ages of the corals. This was very shocking to me that corals in every ocean have this radiocarbon in their bodies, and clear evidence of how much human actions impact the entire globe.
Diving Deep: The ROV was dispatched into the water and soon sunk to around 200 meters. As it cruised along the ocean floor the team watched as a variety of rockfish scuttled by. The ROV has two sets of lasers that shoot out in front of it, each spaced 10 centimeters apart. This gives the scientists an idea of the size of objects or organisms that pass in front of the camera.
The team located the Acanthogorgia habitat and got to work collecting samples using the manipulator arm. The manipulator arm reminds me of the claw game found in most arcades. Andy remotely operated the arm, while Dirk worked simultaneously to control the ROV. Together they were able to collect three exceptional samples, including two Acanthogorgia corals attached to hefty rocks. Each time the manipulator arm reached towards a coral, the whole crew of the Shimada held in their breath in suspense. Would the arm be able to grasp its target? The live footage from the ROV is now being streamed throughout the entire ship; in the lounges and staterooms too, so Andy and Dirk had a quite an audience cheering them on!
The samples made it back to the ship safely. Branwen prepared the coral to take back to the Keck Science Department of the Claremont College where she and her students will conduct their research about this little known species of coral.
Thinking about the effort it takes to research deep-sea coral, involving ROVs and commissioning ships to reach their remote locations, it’s no wonder we know little about them and so much more about their shallow water relatives.