What's Troubling Coral Reefs?

This is a small portion of a coral with a white growth anomaly that is like a tumor. Diseases like this can spread over coral tissue, either making it more vulnerable to other threats or increasing coral mortality.

Corals thrive under very specific conditions. For this reason climate change and ocean acidification threaten coral fitness and health. Coastal development also introduces stresses to the coral reef environment. These include pollution, destructive fishing and boating practices, and over fishing. The confluence of these many factors makes corals less fit and more susceptible to disease. One of the research goals of this expedition is to better characterize disease in healthy populations in order to better understand disease in stressed populations. 

Disease is present in all populations of animals, but as you might expect, when a population is already stressed an opportunity is created for disease to gain a stronger foothold and destroy that population. One example is that of the Caribbean.

Before the 1970’s the Caribbean coral reef was flourishing. However, overfishing removed almost all the herbivorous (vegetarian) fish.  The lack of herbivorous fish to crop back algae (like seaweed) creates an opportunity for algae to outcompete the coral for space. At the time, there were still lots of urchins around to eat the algae. Unfortunately, as coastal development continued and additional stresses accumulated, a disease outbreak devastated the urchin population. This tipped the balance in favor of algae, and the algae progressively smothered the corals.  If you visit the Caribbean today, most of what you see is algae and dead coral. There are still some live corals, but they are very different from the types of coral than once lived there.

Although the general story of the Caribbean is a sad one, we do find hope for Caribbean corals in the reserves. These small reserves demonstrate that, with proper management and conservation, the coral reefs can recover to some extent.

The next goal is to create measures to also protect Hawaiian coral reefs, which are presently following the destructive path that we saw in the Caribbean.  These measures include managing fishing and pollution, and monitoring and treating coral disease. Fortunately, scientists, like those on this ship, are discovering more about what diseases are present in healthy and stressed populations, and are developing ways to treat them. Their research will go toward preserving coral reefs in US waters and worldwide.

Village Tour

The children of Kapinga followed along with us as we toured the island. I have my new woven purse and coconut water to-go. Note the architecture of the dwelling in the background. (Photo by A. R. Dona)

Whenever we arrive at a new atoll, Konrad goes ashore to request permission from the chief to study their reefs.  This is always a delightful experience for the few scientists and crew who are able to accompany him and glimpse the island lifestyle that is so different from our own.  At Kapingamarangi, I was thrilled to join Konrad for the initial visit to gain permission, and again two days later, for a longer visit to tour the village.

The people of Kapinga were quite modest but also very friendly and welcoming, generously offering us coconuts upon our arrival and allowing us to tour their village. On one atoll, they gifted Konrad with a beautiful sarong, and they piled our boats with coconuts and bananas. On Kapinga, they offered woven palm purses and wood carvings for purchase.  We brought a heap of toys, games, t-shirts, DVD’s, school supplies and non-perishable foods to thank them for their hospitality.  

I especially enjoyed giving them my hula hoop.  I demonstrated before a crowd of children, but they were too shy to try immediately. So I asked another scientist to be the sacrificial jester and demonstrate his not-so-good skills.  This broke the ice and a brave young girl mustered up the nerve to try. She was great! I wonder if they already have hula hoops here and the joke is on me!

The village layout reminds me of a campground, with a looped walking path and plots of land on either side.  Each plot has structures made of tree trunks propping up thatched roofs under which people lounged in hammocks or sat on stumps preparing food. If there are walls, they are of woven palm.  Each family owns pigs and chickens, which they reserve for special occasions.  They also have plots of land for growing taro, and they harvest bananas, bread fruit and coconuts from the trees. Each family also has a simply water distillation system that they use for drinking water if there is not sufficient rain. 

Each atoll has a small elementary school.  For high school and college, the students must go to the larger islands. The only transportation between the islands is the supply ship that comes three times per year. This means that students might not see their families for several years at a time.

The school is a concrete structure with desks and chairs in the class rooms as we would have. There is a tall pile of well-worn text books in a room that they hope to turn into a library. They learn English from a very young age.  Although some are too shy to speak, they understand very well. There is a basketball court in front of the school that is converted to a volleyball court by setting up a handmade net on wooden posts. The school has solar panels donated by the EU development funds. These give the people some independence from the delivery of batteries and generator fuel by the supply boat. However, when the system breaks, it requires either creative engineering to fix it with limited resources, or patience to wait for the resources to arrive.

The people generally seem happy, healthy and strong. Those with whom I spoke said they do not feel want for food or water. I imagine the biggest stresses derive from the failure of radios and solar panels or the lack the medicine to treat an illness or medical emergency.  

I spoke with two young men who were schooled in Pohnpei, the capitol. One wishes to go back to Pohnpei for work or to join the US Army. The other returned to his small atoll because he prefers the lifestyle there and believes it is better to raise his children on the atoll rather than the capitol city. 

Kapinga children hula hooping. (Photo by A.R. Dona)

Why I do the Drifter Deployments: Ocean Acidification

This figure shows the increase in the concentration of carbon dioxide in the atmosphere over several decades (red line). It also shows how this leads to an increase in carbon dioxide in the ocean (dark blue line), which in turn causes the pH to decline (light blue line). Lower pH means more acidic.

The primary reason that I do my research is to understand how the chemistry of the ocean affects coral reefs. I am hoping that my research will help scientists predict how corals will respond to ocean acidification in coming decades.

Ocean Acidification is the process by which the ocean becomes more acidic. The root cause of ocean acidification is the burning of fossil fuels, which adds vast amounts of CO₂ to the atmosphere.  The ocean absorbs one-third of this carbon dioxide from the atmosphere. The combination of CO_2­­­ and water results in the production of carbonic acid – keyword: acid. 

Organisms tend to be very sensitive to changes in the chemical environment around them.  The acidification of the ocean is affecting marine organisms by disrupting their metabolic processes and behavior and thereby rendering them less fit. By extension it is also disrupting entire marine ecosystems.  Global change is happening too quickly for organisms to adapt. 

Corals are especially sensitive to ocean acidification, because their skeletons are made of limestone – a mineral that is easily dissolved by acid. I am studying how the chemistry of seawater affects corals in the natural environment, within the context of their diverse community and fluctuating conditions.  I hope that by better understanding the impacts of ocean acidification on coral reefs, we will be better equipped to mitigate detrimental effects.

Why we care about coral reefs.

The boulder-like corals build the foundation of the reef, and the branching and plating corals create the spatial complexity that harbors the tremendous diversity of life in coral reef ecosystems.

The diversity and complexity of coral reefs makes them on of the most valuable ecosystems on earth. The net benefit of coral reefs amounts to roughly $29.8 billion and includes benefits from tourism, fisheries and coastal protection. However, reefs also provide numerous benefits to which a dollar amount cannot be easily assigned. 

Yesterday, I spoke with an islander from a village of 300 people.  He raises some pigs for their meat, but, like his neighbors, saves them for special occasions. A supply ship comes three times per year to deliver non-perishable staples like rice. But his primary food is fish, which he eats almost every day. This makes him one of the almost one billion people worldwide who rely on the ocean for their primary source of protein.

Although most Americans do not rely on sustenance fishing as do these islanders, our fish consumption is also affected by the health of coral reefs. About half of federally managed US fisheries depend on healthy reefs. This is because coral reefs serve as spawning, nursery, breeding, and feeding grounds for a wide variety of fish and marine animals. 

This diversity of coral reefs attracts people who simply want enjoy their beauty. Coral reefs are the principle asset of many tourist-based economies, such as those of Hawaii, Florida, the Caribbean, and Southeast Asia. The reef-based tourist industry brings revenue to local businesses such as dive and recreational fishing operations, and hotels and restaurants, and it brings revenue to the state through visitation fees and permits.

Coral reefs also act as natural buffers against waves and storms. This helps prevent loss of life, property damage and coastal erosion. Each meter of reef in the U.S. protects a about $47,000 of property value.  As reefs decline to rubble due to anthropogenic stressors, it becomes necessary to build costly infrastructure in an attempt to replace their buffering functionality.  

Chemicals produced naturally by organisms found in coral reef ecosystems are important sources of new medicines and cosmetics. These include medicines that induce and ease labor and that treat cancer, arthritis, asthma, ulcers, and a wide variety of viruses and diseases.  We have only just begun to explore the natural chemical products of these organisms, and our opportunities to discover new medicines are presently dwindling, as coral reefs, the “medicine cabinets of the 21st century,” are continually damaged and degraded.

Finally, there are the cultural and spiritual values of coral reefs. Many people who live near coral reefs include them in their way of life.  In our attempts to preserve the diversity of culture within our global community, we must also preserve the ecosystems that are central to those cultures. 

While diving today, I was reflecting on how I am completely captivated by the color, complexity and activity of coral reefs. These underwater "cities" of fish and coral, crabs and clams are like a wonderland with thousands of surprises to discover. The enjoyment I get from these reefs is invaluable, and I hope that the reefs survive for other generations to enjoy them as well.