Before our second visit to the MBRS we encountered some local fishermen, who told us of crabs they’d caught with pitted and damaged carapaces. Hmmmmm, we thought. A potential symptom of acidification! But how could the crabs have been exposed to low pH waters like those predicted to occur 50 to 100 years into the future?
A day of detective work followed at the site of one of Straddie’s mysterious forest springs, which injects acid spring water onto the local seagrass meadows. Some water chemistry analyses and clever calculations by our GS students indicated that this site could be the source of the acidified seawater. And so we had discovered a wonderful field site – a natural simulation of our future oceans.
Of course, this meant that there was no need to deploy our portable Free Ocean Carbon Enrichment system to inject carbon dioxide into local waters. Instead, we spent time in the mangrove forest, tracing the path of the acidified water out to the shore and designing our new experiments.
Our goal was to first determine if the seagrasses growing near the spring were altered. We started by testing their value as food for local grazers….starting with the rabbitfish, an important seagrass herbivore also know as the “happy moment” fish. (It’s a cute fish, but like everything else here, it is venomous.)
Papers, papers, and more papers
The University of Queensland is home so many expert’s on climate change, and particularly the phenomenon of ocean acidification. Acidification is the result of carbon dioxide entering the oceans from the atmosphere and being converted first into carbonic acid, then lowering the pH of seawater. These chemical changes trigger others, making it difficult for calcifying organisms – such as shellfish and corals – to form their shells and skeletons. It’s a global issue, sometimes called the “other CO2″ problem, which affects plankton at the base of the food chain, corals, clams, and fish. Coral reefs are particularly affected, as are shellfish. Coral growth slows dramatically at low pH, then stops. And many aquaculture facilities find it difficult to operate using low pH seawater they pump from the oceans.
And this is why we’re here this semester. The challenge posed to the students was this: tell us how future acidified waters will affect Moreton Bay’s primary habitat: seagrass meadows.
Step one, was to read, read, read. And learn from a variety of guests who visited to tell us about their work on our changing oceans. Thanks to Profs. Sophie Dove, Sharon Strauss, and others who took time to visit with us. And a special thanks to Prof. Ian Tibbetts, our collaborator in Brisbane!
Good on ya, Global Scholars!
Seventeen Dickinson students participating in a new research-intensive course, arrived in Brisbane in January at the height of summer and immediately dove into the new Global Scholars program with Prof. Tom Arnold. Before they were over their jet lag and well before regular courses began at the University of Queensland, these students found themselves transported to North Stradbroke Island, the world’s second largest sand island. On “Straddie” they lived and worked at the Moreton Bay Research Station to study the potential impacts of climate change on Moreton Bay, home to vast meadows of seagrasses, fish, turtles, dugongs, and at times hundreds of migrating whales.
Starting out on Moreton Bay
There are more venomous and deadly sea creatures in Australia than anywhere else. So the course started with a critical creature identification quiz – including the deadly blue ring octopus, the cone snails, and the nearly invisible stone fish, all of which inhabit the waters of Moreton Bay. Next we visited each of the island’s habitats such as seagrass meadows, sand flats, the rocky gorge at Point Lookout, and some mysterious acid springs flowing through mangrove forests – all carrying our Wild Guides to Moreton Bay supplied by the Queensland Museum. Our species lists grew longer on each trip as we spied guitar sharks, soldier crabs, and tiger cowries, among many other creatures. Then it was one class after another – the Earth’s geologic history, climate science, ocean acidification, and marine ecology – through to the evenings. We ate and slept at the station. It was a good start for the Global Scholars program, and all before orientation week at the University of Queensland!
Our dining room. With a nice view of Moreton Bay!
The Global Scholars program is an initiative to promote student scholarship at our partner institutions abroad. This program allows select Dickinson students to join a faculty-led student research team to study issues of global significance while participating on a Dickinson study abroad program.
In spring 2012, the Global Scholars program will be based at the University of Queensland, Brisbane, and at the Moreton Bay Research Station, Stradbroke Island, with Dickinson professor, Dr. Tom Arnold.
Our oceans have absorbed about a third of the carbon dioxide emitted since the dawn of the industrial revolution, slowing climate change. Unfortunately, this absorbed CO2 changes our ocean’s chemistry – it carbonates seawater much like CO2 carbonates fountain drinks. In what is commonly called “ocean acidification” carbonic acid is produced and lowers seawater pH. Sodas become acidic enough, with a pH near 3, to break down the surface layers of your teeth! The pH of carbonated seawater doesn’t change nearly this much – but the changes still are enough to boost CO2 levels over a hundred times and destroy important ions called carbonates, from which corals make their skeletons and oysters, mussels, and snails make their shells. Ocean acidification disrupts the growth of most organisms that make these calcium carbonate skeletons or shells – often they grow more slowly or not at all; sometimes they die. It disrupts the ability of clown fish to locate their host corals. It also alters the transmission of sound underwater.
Government agencies and scientific groups are urgently calling for new studies to discover how ocean acidification will impact marine organisms and communities.
One challenge has been- how can we mimic ocean acidification to study it?
On land, scientists use systems called Free Air Carbon Enrichment (FACE) systems that emit extra CO2 into the air over forests or farmlands.
But dissolving CO2 into seawater to accurately mimic acidification is a tougher challenge.
Prof. Arnold’s lab is one of the few groups to have developed a working system – called a Free Ocean Carbon Enrichment (FOCE) system – that allow scientists to observe the response of organisms in ‘acidified’ waters. For three years he has been testing and operating the FOCE system in the Gulf of Mexico and the Chesapeake Bay, and working with scientists from the Smithsonian Institution to explore the impact of acidification on estuaries.
Now he is taking the FOCE down under! From January to June 2012 he will be observing the impact of acidification on the seagrasses, urchins, fish, and dugongs of Moreton Bay, Australia. He is searching for a group of dedicated students – from all departments and divisions across the Dickinson campus – to join his team. Students with an interest in the marine biology, the environment, technology, policy, communication, and education are encouraged to join in to study this global issue.