Using Isotopes to Understand the Effect of Global Climate Change

Dr. Maite Maldonado wants to take you on a journey to the Arctic. The University of British Columbia professor, Canadian Research Chair II member, and IsoSiM supervisor extraordinaire is using isotopes and phytoplankton (microscopic algae) to better understand global climate change. If you are a problem solver, can embrace the cold and you don’t get seasick, you may be just the type of student Maite is looking for.

Maite’s research hinges on the unique location and composition of the Arctic Ocean. Indeed, Arctic waters are experiencing the greatest increase in acidity in the global ocean “What makes the Arctic ideal to study the effects of global climate change is that it is a land locked ocean with many rivers draining into it.” These rivers carry lots of freshwater, which has low alkalinity. Alkalinity is what controls the buffering capacity of seawater (the ability of seawater to deal with acids; like when CO2dissolves in H2O, and becomes carbonic acid, it is the seawater alkalinity that neutralizes this acid). In the Arctic, due to large river inputs, the seawater alkalinity is being diluted, as it is mixing with large quantities of low alkalinity freshwater. This means that when you dissolved atmospheric CO2 into the Arctic Ocean, the pH of the water drops much more significantly than in other oceans. This low pH in turn affects the bioavailability of trace metals in seawater – metals that are essential to phytoplankton, the primary producers of the ocean.

Isotopes for Science and Medicine | IsoSiM | TRIUMF | UBC | Earth Ocean Sciences

Phytoplankton are not only at the bottom of the ocean food web, but they are also an atmosphere balancing powerhouse, responsible for 50% of the global photosynthesis, and sequestering annually  ~45 Gigatons (1 GT = 1012 kg) of atmospheric carbon dioxide (CO2) to organic carbon. “If all the phytoplankton in the ocean die, the concentration of CO2 will skyrocket” Maite notes. Her work in the Arctic seeks to address questions about the physiology of phytoplankton, particularly the mechanisms they use to cope with low iron levels in the ocean. Iron is an essential nutrient for phytoplankton. The concentration of dissolved iron in the ocean is akin to a single paperclip in 130 Olympic sized swimming pools. Luckily, phytoplankton are efficient in their metal uptake; if dissolved iron was a paperclip, phytoplankton would be able to collect enough of these paperclips to make up an entire compact car.

As the acidity of the ocean increases, the bioavailability of trace metals is affected. This has huge implications for phytoplankton growth, as they need a careful balance of iron and other metals in order to survive. Phytoplankton in the Arctic are being hit with a “double whammy”, as Maite puts it, because the change in ocean pH might lead to low levels of iron and high levels of copper, a metal that is toxic to phytoplankton in too high concentrations. While doing research in the Arctic, she and her team used an isotope of iron, iron-55, to see exactly how trace metal intake by phytoplankton is affected by lower pH. What do you need to join Maite on one of these research trips? A passion for research, a creative mind and, Maite notes, a positive attitude.

Jingxuan Li, an IsoSiM masters student who, after receiving his bachelor’s degree in Marine Science from Xiamen University in northeast China, jumped at the opportunity to participate in Arctic fieldwork. IsoSiM is a joint program between UBC and TRIUMF that addresses the growing need for applications of isotopes in science and medicine. For Jingxuan, IsoSiM was an opportunity to participate in international conferences and exchanges. Maite and Jingxuan have participated in two legs of the Canadian GEOTRACES Arctic Expedition together travelling from Québec City, Québec, to Resolute, Nunavut, a small community with a latitude close to 75º North. Of course, the fieldwork for this trip came with its own set of challenges. 

Isotopes for Science and Medicine | IsoSiM | TRIUMF | UBC | Earth Ocean Sciences

An array of water sampling bottles, called a rosette, would be sent down 50 metres into the ocean to collect water samples at several different locations in order to observe the phytoplankton’s ability to take in iron. The boat operated for science 24 hours a day; exhaustion was inevitable. “All the professors and scientists had to endure the tiredness,” Jingxuan admits, but their optimism and enthusiasm for the work inspired him to push himself. It wasn’t without its moments of beauty either. “After every period of work, I made a coffee and enjoyed the beautiful scenery of icebergs, sunsets or even polar bears.” The final outcome is rewarding, says Maite “With each voyage you can easily get two research papers out of it.”

Isotopes for Science and Medicine | IsoSiM | TRIUMF | UBC | Earth Ocean Sciences

The research that she and Jingxuan are doing will contribute to a better understanding of how climate change is affecting the ocean's primary producers. In the past, people have suggested adding iron to the ocean in the hopes of manipulating phytoplankton's carbon-fixing ability to cool the earth. Mate is strongly against the idea. "We don't properly understand the ocean and the effects dumping lots of iron could have," she argues. "Out best hope is to continue to do research to understand the problem, and in the meantime, look at our own daily consumption to reduce our carbon footprint."

Isotopes for Science and Medicine | IsoSiM | TRIUMF | UBC | Earth Ocean Sciences

For those with a passion for the environment and a hunger for adventure, the IsoSiM program offers the ultimate balance between science and social change. Jingxuan encourages all students to get involved. "The IsoSiM program gave me access to experiences, challenges, and friends, which you would not get from other graduate programs." Maite adds that, "You learn so much from your peers through the interdisciplinary nature of the program. The flexibility and workshops offered set the program apart from any other graduate program." If you have the stomach for life at sea, get involved with Maite and start your IsoSiM story with a journey to the Arctic.

Isotopes for Science and Medicine | IsoSiM | TRIUMF | UBC | Earth Ocean Sciences
Nic Zdunich